[Transfer] system analyst paper 12 articles
Papers 1
Application of Enterprise Personnel Information System
【Summary】
This article discusses the demand analysis methods and tools of "Enterprise Personnel Information System" project. The construction goal of the system is to help the company to manage people and personnel within the enterprise. Personnel information management refers to the whole process of enterprise employees from recruitment interviews to retirement, including interviews, report, training, rising Duty, separation or other personnel changes, including electronic attendance, payability, and related records of other company resources (such as dormitories, insurance, documents, etc.). In addition, the system also involves the management of personnel information management across the country, the organization's organizational architecture setting, level and job management, and human application until human demand reports, thereby forming a person's information management application system that is truly useful to the company. In this paper, the main reason and strategy of selecting object-oriented methods and tools is discussed, further illustrating the effects of this method and tools through a special example, and discussing the necessity of using multiple tools and methods in demand analysis, final Briefly summarize the meaning and role of selecting the correct tool and method.
During the project development, I served as a large amount of work such as systematic analysis, system design and database management.
【text】
Personnel Information Management System is a practical system with wide application, however, my country has its own system, mechanism, characteristics and different requirements; when developing such systems, system demand analysis is an extremely important ring. In the entire analysis process, we have adopted object-oriented analysis methods because we have convinced that this approach can be more effectively expressing and describing the real world in recent years. Software should have applicability and scalability, it must be closer to the law of the real world itself.
From a simple example, assume that the design requires a system that introduces talent assessment, according to our past practice, first request to provide us with a relevant introduction talent assessment table, then design the corresponding form in the gourd painting With the interface. In the short term, this is simple and practical, but it does not meet the long-term goals of the real world. This design method does not have scalability because there may be many changes in the structure of any assessment table. Using object-oriented methods, you can extract elements of the table, table structure, score method, and various aspects of the inheritance, so that software can be guaranteed, configurable, and maintainability.
During the selection of tools, we have chosen the Rational series, including Rational Rose, RUP, SODA, etc., why do you choose this series of tools? This is based on our views on the analysis of software requirements. We believe that the analysis should correctly answer several key issues:
(1) Does the user's demand is detailed?
(2) Can users understand or understand what we describe?
(3) Analyze if it will segment with the design,
(4) Can programmers understand our analysis and design requirements? and many more.
The following is a brief description of the above problems one by one.
(1) Acquisition of users in detail.
User needs can be divided into explicit demand and hidden demand, and users' tendency often take into account current and obvious needs. To achieve the comprehensiveness of demand, it is not only to rely on effective user conversations and investigations, because users we face often have some side, using Rational Rose (based on UML), and multiple pictures Union use, you can find out what to miss.
(2) User can fully understand our representation method, can truly understand what we described.
Software demand analysis specifications are usually lengthy and boring, and the general users are not easy to understand, which weakens the correctness of the analysis. By supporting an object-oriented and UML language, it can communicate with users, allowing users to understand the operation of the system and even details of the system. (3) Contact and penetrate the analysis and design of two stages.
This is an important reason why we choose object-oriented methods and Rational Rose tools. The system analysis should describe the user's needs, but also the solution, and the solution should of course include design (program), database and system configuration. We certainly do not want the user to get a software that does not have the same requirements, and it is impossible to request a programmer to complete an indispensable task. However, we often discover such circumstances in the previous many work, as systematic analysis and design are out of the analysis, causing a one-to-analyzer that is related to the design.
Analysis and design is not conducive to the design of the description of the current instructions, because analysis often will be separated from reality, leading to the lack of assessment.
Because it is impossible to successfully complete the design, it will cause huge waste and loss. A good tool allows the analysis and design more closely, even - one correspondence. Object-oriented analytical methods reduce the relative independence between objects, reducing any changes in global changes, avoiding passive waves due to changes in demand.
(4) Let the programmer understand our design.
A good design should make the programmer feel clear, less questions. A lot of designs plus communication is not smooth, and there will be another software that is not needed in the application environment, so design specifications must be clear, image and clear, of course, Rational Rose has sufficient graphics and other forms, energy Make the programmer more clear, even fine to each statement (in fact, if you use VB, the programming architecture can be generated directly).
(5) Selecting UMLs may have more reasons.
For example, the writing of user documents, database design, we need to do continuity, automated support and quality assurance.
Therefore, we choose the above methods and tools.
In the analysis, in the face of the problem of attendance, the user has formed a fixed concept because of the use of a paper card, and many attendance software now use multiple credit cards to form a day record. Object-oriented analysis, it can be found that in fact, it is formed by a number of time-based records, and how much is in various companies, each type of work is not the same, and each time period may have different attributes, time periods The time period combination can be formed as a class, which is more suitable for reality, making it more flexible and more scalable. In fact, there is also a relationship between heavens and days. At this point, we have found that we must add the basic concepts of the period (Periods) similar to the MRP and the salary salary, such as that can be called the attendance period, allowing users to set the intermedial period, It may not be the same as the natural day and the day.
Rational Rose makes us more convenient to implement the above ideas on the class, further designing our high efficiency database.
Of course, it is impossible to use a single tool to complete the demand analysis of a large-scale application system. Because social development, users' demand is also changing, how to grasp the needs of users is time, object-oriented methods, sometimes ignore the external requirements, not only to get critical needs, others Many demands often wait until the user knows after use, but the user is not realistic, as the prototype in the prototype development model is also a class of comparable effective methods and tools that describe user needs, describing and explaining demand. During our development, in order to better let users know our system and our design, let users get more direction and targeted on the meeting, we first use Access to develop prototypes, allowing users to try first. In this way, we can more in line with users in real analysis and design.
In short, the software needs analysis method and tool use, the impact of our software development process is far-reaching, selecting high-efficiency correct methods and tools, allowing our software to more correctly reflecting real demand, more availability, scalable Sex and maintainability; reduce the risk of software projects.
Comment: (1) Write some characteristics and distinct views. (2) Abstract is written, reflecting the contents of the project, and is also summarized. (3) Although the examples mentioned in the article are simple, they are actually practical. (4) A variety of methods and tools are described in the narrative. (5) The content can be more abundant, and more in-depth examples can also increase more, it will be more convincing. (6) There is too little description of the whole process of demand analysis. (This article mainly refers to the papers of Guangdong Yan National Day and others)
Papers 2
Enterprise Group's Information Management System Application
【Summary】
This article is based on the development of an IT product sales company's information system project, discusses the entire process of information system demand analysis, and its important feature is that the project involved is an upgrade version of the original system. Therefore, the demand analysis process is different from the establishment of a new system, which can generally be divided into three phases: () implementing the reverse engineering to obtain a preliminary understanding of the system; (2) Writing basic demand on the basis of step 1, Supplement by the customer review; (3) Develop prototypes on the basis of step 2, using prototype and customer exchange, and finally obtain baseline requirements. In response to the above three stages, this paper discusses the analytical methods and tools used, and some of the typical issues and measures encountered, and finally talk about some of their own preliminary experiences in demand analysis.
【text】
I participated in the development of a large group of corporate information systems from August 1998 to July 2000, which mainly involves the transfer of IT products. I am responsible for systematic analysis in the project, the group company has originally entrusted a computer company to develop a set of IT product management systems, but there are two main issues of the old system: (1) The system is very slow, If the sales list is started, the response time for the customer will not endure from the determination of the response time to the list of 1 to 2 minutes. (2) The system data is not accurate, and the physical inventory and computer inventory have often occurred, so that the statistics of the sales data produces some confusion, and the data on finances can therefore be effectively used, and can only be supplemented by manual entry. In this case, the Group's general manager decides that the original system re-develops a system to solve the above two difficult problems existing in the original system. Note; the original system uses PB6.5 development, the database uses Sybase, the server uses Windows2000Server, the client uses Windows 98, and the program architecture uses the traditional C / S structure. In view of the complexity of the group's business, there are many characteristics, involving many personnel, as well as short-term completion time, limited funds, limited staff limited, and considering the need to avoid structural confusion and difficult to maintain the previous system We decided to make a relatively thorough and practical analysis of the needs of the original system. Since the original system has developed for nearly two years, and the customer has certain experience, the basic process itself is not too big. Change, therefore, we divide the process of demand analysis into three steps: () Analyze the structure of the original system, mainly the database structure and program structure, (2) Write basic needs on the basis of subsection (1) Concert to the customer review complement, (3) Develop prototypes on the basis of step (2), using this prototype with customer, thereby obtaining the result of the final availability. The following three steps are discussed separately.
The first step is to implement the reverse engineering and obtain the basic needs of the original system.
Since the original system can basically basically meet the needs of our customers, many experiences have been accumulated in more than two years of development, and therefore, some useful references can be obtained, or more into the way. At this stage, the main tool we adopted is Power's own Power Designer and Pb documents; the former is mainly used to analyze the database structure, the latter is mainly used to analyze the program structure, which is convenient for developers and advanced users to understand the procedures. The reason for the use of these two tools is that the original system is too large, the module is more, the database mode is much, the table is very large, and it is difficult to obtain a relatively complete, clear system structure and overall. There is a system failed to provide a set of proper and complete and effective design documents, so we can only rely on tool assistance. After using POWER Designer to analyze the database, and after PB Documents analyze the PBL in the original program, we have a preliminary understanding of the structure of the original system, and combined with the use of the original system, basically clear the needs of function and process, and On this basis, the natural language document of the initial demand is produced. Here, it is pointed out that the use of Power Designer is: if there are too many fields in a table, and when you rely on multiple tables, the output form-related graphics is complicated, there are many intersections, and it is difficult to adjust, it is not convenient to read And print. The second step is to perform on the basis of the first step, that is, the basic needs of the system are written, and the customer is reviewed and supplemented.
Through the first step reverse engineering, we have obtained the basic needs of the system. In order to fully record the dependencies between the changes and requirements, we decided to use Rational's Requisite Pro as our demand management tool, Rational Company has a set of tools for demand management, which is very powerful, including Requisite Pro, Clear Quest Wait, these demand analysis tools can be fully managed, including changes in records, dependencies, and more. However, we have considered a comprehensive implementation of Rational's set of tools that will be very expensive and complex. It is necessary to fully implement it. Therefore, we only use the simplest part of the function, that is, record demand changes, record demand The dependency between, and other functions related to RUP are given. The reason why this is mainly considering the project's funding, humanity, and the actual situation of domestic software development. As mentioned earlier, we will make an appropriate supplement according to your own understanding and writing basic needs, and we will make an appropriate supplement to the customer. We will submit the needs of the Requisite Pro as a formal demand as a formal demand, and The needs of each requirement, setting priority, etc. After these work is completed, you can intuitively understand which needs in the database, which needs to be prioritized, which needs must be prioritized, which is difficult to have more difficulties. In this process, we have encountered some problems, such as: users do not understand the demand documents written by our natural language, often spending a long time reading, still do not understand the demand process we describe with them The correspondence between the completed business; in addition, due to the first use of Requisite Pro to perform demand management, some developers have no experience in the type division, attribute value, and there is a lot of repetitions, for the former, our method is If you want to increase some schematic, you will break the big process into small processes, and then repeatedly communicate with our customers, and ultimately meet the same purpose of both parties understand. For the second question, refer to some examples, and then combine the use of the actual properties, give alien or selection. After this stage of work, we have established a basic demand library, which has set a basic demand specification. The third step is based on the second step, and the original type is established, and the prototype is more in-depth communication, and the corresponding needs are modified by exchange.
At this stage, the work is based on the report exchange of the second step. We use PB to develop a prototype system, communicate and communicate with customers, through prototype, customers discover many places we don't coordinate with their understandings, we are in revuration, also in Requisite Pro The modified history is recorded in the demand database. It turns out that the role of this record history is very effective. If there is a customer who has made the opposite demand in two different times, we have confirmed the method of the customer according to the historical record, in There is no need to argue in front of the facts, and we have discovered some contradictions between demands with Requisite Pro. After this phase, we finally got the user-recognized demand baseline, ie, baseline requirements that can be used in the next step.
In this project, we used the reverse engineering tools and Requisite Pro demand management tools such as Power Designer, Pb Documents, which enhanced productivity and played a certain assistive role. However, in terms of demand analysis tools. We feel that domestic application is still too few, this is because the analysis is not valued for demand, and on the other hand, it does not reach the corresponding level because the management level is not reached. Rational's set of demand analysis tools, its function is very powerful, foreign use in general, gradually began to popularize in China, especially those who have reviewed by CMM secondary level, must be used to manage requirements. . In this project, we only use some small aspects of the Requisite Pro feature, which has experienced the benefits of this tool for project management. If a powerful company can fully implement RUP, the problem of managing this old difficult problem will not be so tricky, the quality of the project will also be improved. At present, due to the rise of CMM boom, it has gradually attached importance to demand analysis, and gradually uses demand analysis tools. This is very gratifying, of course, more hope that in the near future, can use domestic demand analysis tools, then our software The industry may really take off. Comment; there are many applications with retrograde tools for re-engineering, and this article gives an actual example. Writing is organized, and it is also very practical. Reasonably define the reality level of demand analysis. The method of demand analysis is relatively reasonable for the needs of the needs. Can express the discussion, experience, patriotic heart and career heart while discussing the project The depth can also improve, and the example should be more abundant. (This article mainly refers to the papers of Guangdong Liu Xiaobo and others.
Papers 3
On Software Demand Analysis Methods and Tools - Paper 3: Application of Communication Industry
【Summary】
This paper is developed as an example with the development of a communications company, and the selection of software requirements analysis tools and methods are discussed. We believe that software demand analysis is an important step in software engineering, directly related to subsequent engineering, and whether the ultimate product can meet the needs of users, so it plays a key role in the entire project. With appropriate tools, it is possible to significantly reduce errors in the demand phase, or greatly improve the quality and work efficiency of demand analysis. Of course, the selection of tools should be combined with the actual items and fully utilize the role of the tool. This article combines the actual experience of our work, briefly discusses the tools and their applications used in the development system and their applications, and the problems encountered. In the text, it also combines a variety of development methods (ie the traditional waterfall law, information engineering method, object-oriented method), pointing out the deficiencies of various methods, explaining the role of the tools we use on software demand analysis. And the effects of the corresponding result.
【text】
I worked in a city communication company as a technical bone, the leadership commissioned, participated in the development of the company's business report system, I served as the system's demand analysis, overall design and partial code preparation.
As a communication operation company, my company is divided into three levels of headquarters, provincial companies and land-level branches, and all levels of companies have data statements. However, every sub-city branch is different from the place where the business environment is different, and the problems faced are different, so it has formed a distinctive data report (except for the provincial companies reported to the provincial company) . The company is divided into many departments, which also require data as the basis for analysis decisions. Therefore, understanding the needs of various departments become the key to the business report system.
In the process of investigation, I chose a tool called Play Case, you can download freely from the Internet, with a strong function. Let's introduce it to how I use this tool during the needs analysis phase. The first step is to understand the business organization structure. The company's internal data is actually flowing between sectors. The business department needs to know the traffic volume of each base station in the area, the traffic volume (ie the time and space distribution of traffic). Finance department needs to know the income income, pre-payment income, pre-payment, and other telecom operators. The planning department needs analysis of various departments. The billing department needs to provide the account statistics of this month, and the statistics distribution of the bill (for example, according to the distribution of base station, time period distribution, and according to user category), the pre-deposit statistics, current distribution of arrears, and pay the situation and many more. These sectors often have a large number of unnecessary controversies for data. When using the Play Case tool, first enter these departments into the "Business Department" of Play Case. The receiving point (or send point) of a source of information is constituted; the Play Case represents the relationship between the sectors by illustrating, and converted into a corresponding software structure. In fact, this is a method of modeling, that is, transforming the individual organizations in the business system into various structures in software functions. In this way, in the demand analysis phase, it is clear which departments need data, thereby ensuring the need to analyze the comprehensiveness of the entire company, without ignoring a certain department, leading to incomplete demand analysis.
Step 2, understand the business processes in each business unit, making it a dynamic modeling method through the Play Case to switch into software. On the previous step, track the behavior of each department, enter the Play Case, and describe the processes in a formal language. For complex processes, the tool also provides a further refined method and forms a business flow chart and a business state diagram. According to these flow charts, the state diagram is compared with the business of the actual business unit, or is more consistent. During this step, dynamic modeling technology is used to make the situation of each department business process reflect the operation of the software, thereby ensuring that the description of the operation process in the demand analysis phase can truly reflect the actual situation and prevent it. During the subsequent programming process, a class of cases that may occur often: the programmer has a "closed door" phenomenon because there is no understanding of the business process, and the software is guaranteed from the software functionality.
In the third step, transform business data into software data, this step is actually the data needed to collect various departments. Analysis of the data needed by each department; and how the data is converted, this can be classified into the "function modeling". This corresponding data is entered into the Play Case, select the department to which you belong. At this time, the DFD map (data flow chart), the data dictionary, and the province have saved the troubles of manual establishment.
In the fourth step, turn the business data relationship into the data relationship in the software. Here, an object-oriented method is used, and the data required by the business unit is used as an entity, and the data relationship between the department is the relationship between the entity. For example, the user information required by the business department, the user's call, actually the relationship between the entity of the user and the entity of the bill. Play Case provides a component (but I think it is more appropriate) to indicate the corresponding data, and provides the relationship between the three components, the assembly relationship, classification relationship and the connected relationship. These three types of relationships basically reflect the relationship between business data in the real world. For example, the user data in the real world is represented in the Play Case, the user component can be represented by a connected relationship with the billing component. This method is actually a concept of objects, gathering, inheritance, packaging, etc. in OOA-oriented analysis methods, can better reflect the real business; at the same time, this step is also the overall design database The concept pattern design lays a good foundation. After experiencing the above four steps, the Play Case tool automatically generates a software demand specifications, a preliminary DFD diagram, and a business flow chart to make the foundation for the next overall design.
With the Play Case tool, the demand analysis can inherit the traditional structured analysis method, and can absorb the advantages of object-oriented design methods. For example, it is reflected in the structure of the business process into a running process, and the business organization is converted into software. During operation, the subdivision and tracking of the complex process reflects the analysis of the analysis of the above-bottom-up decomposition in the traditional approach, which is very helpful for solving the analysis of complex systems.
By using, I think this tool is still very nice. Because it actually combines the following four aspects: software, business, developers and users. For the user, Play Case shows the business process in a graphical manner, enabling the user to understand the operation of the business in the software, provides the basis for the future acceptance software. For developers, developers can make more clear understanding of business processes, and will not happen again. "Because the shutter-made car conditions do not understand the needs of users, the development of products do not meet the needs of users." Therefore, the demand manual provided by Play Case can communicate well between users and developers, so that they can have a common understanding of demand.
After using the Play Case tool, make our demand analysis have achieved good results, not only can automatically provide many results, such as demand instructions, etc. Learning computer, but is very familiar with the company's business); in successive design and maintenance work, we feel a lot of work.
Of course, the software tool also has a deficiency, a protruding problem is not flexible, and the entire design has been renewed when the department or organization of one county company changes. Therefore, in the process of improvement, we reserve a number of virtual sectors in the first step to prepare further expansion or changes in the future.
Comment: (1) Some experiences in specific projects do appear to be good. (2) Capture is clearer, compare the process and experience of using Play Case. (3) Define from the tool discussion, the method of demand analysis is not enough. (4) The project is relatively small, and only the reporting system is involved, and the more complex business processes should be analyzed to more fully reflect the role of methods and tools. (This article mainly refers to the paper of Wei Fujian, Guangdong Province)
Papers 4
On Software Demand Analysis Methods and Tools - Paper 4: CAD Application in IC Industry
【Summary】
This article discusses the main features of the project and the work as the work as the work, and focusing on the specific methods and tools used in the project demand analysis process. Due to the particularity of the project's professional field, divided into two types of different needs discuss the problems and solutions encountered in demand analysis; the description of the effects of the specific tools and methods for the selected use are given during this process. Then, some ideas and specific implementation processes for improvements in the use method are discussed herein. Finally, I proposed some views on demand analysis, emphasizing the importance of communicating with customers.
【text】
In recent years, I have been engaged in the development of IT projects in an enterprise. There is a system for computer auxiliary circuit designs, including all processes from the uplift to the downflow design, such as logic gate for designing millions of gates. Circuit. In terms of respecting the path extraction, filtration, and a software development task in the circuit in the circuit to our company, I have been fortunate to have a demand analysis and design of the part.
The part I have designated is a separately canable software, mainly the linkage path in the parsed file, which is displayed in a list view and a histogram, etc., and functions such as finding and filtration can also be performed.
The principal provides a preliminary demand for this, and describes some basic functions and performance requirements. I have two main points in demand analysis: First, detailed demand for the interface of the software must re-analyze the analysis. Second, the required function requires deepening and refinement to form a true and complete demand analysis document.
After receiving the requirements analysis task, I analyzed the work you're done. Found that due to software in the special field, it is quite high in the professional field, so it is ready to divide this project into two parts:
(1) There is almost no impact on the domain of the interface, but because there is no requirement, it will feel that risks and changes may be the largest.
(2) Functional aspects can be called for the corresponding modules due to many of the functions of the principal, and the simple demand for the corresponding written is existing, and it is only deepened. For the interface, I used some RUP ideas and gradual. The functional demand has taken layered refinement, and each layer is required to confirm, modify, and supplement the debt.
First of all, the larger partial part is completed, which is the basic common sense of modern software development. I chose to analyze the demand for the interface. The first step is to extract the logic model according to the functional description, and the logical model corresponds to the interface element and function, which determines the functionality of the interface, and then determines the specific control according to the interface function, at this time, I will refer to the interface layout and control of the principal, which have been initially completed, and then the function of the control is used as needed, and the Windows and UNIX dual platforms must be supported, so the control library uses QT) class library to select the appropriate Control. When extracting and abstract logic models, I use the case map in Rose 2000, that is, the relationship with the outside is described in the Use-Case diagram. The reason why Rose is used, I am based on the following reasons: First, in the developed part, the principal is unified to use ROSE to create design and code generation of class and sequential diagrams. Second, ROSE provides a standard map to describe the relationship between the system and the outside, a standard structure in a global scale. Third, the convenience of use is used. I use rose's use-case graph to clarify the interrelationship between our software window and the principal window and external role (operator).
After determining the interface element, considering the understandability of the document is not very strong, I use Visio 2000 to draw the appearance of the interface, write the basic control role, then give the entrust party review, fortunately, in addition to several The modification of small features, the client basically approves my solution.
The following work is to develop a corresponding state migration diagram for the behavior and status change of the control. I use the tool is still ROSE. I use the status map and timing chart to describe the status of important control status and corresponding sequence, then subsequent A few days, the corresponding DOC document is completed, and basically the interface design is completed. The following needs are for functional requirements. Although the principal's technical department has a preliminary demand document, because of the specialization of the field, I don't know that the complex path extraction relationships and deeper professional terms have always had a difficult feeling. Only the principle of layered refinement, from the initial deeper into a more than ten articles. In this case, it will not encounter too deep professional problems, and you can continue to learn from the entrustment party and the reply, deepen your understanding of the professional field, so that you are always laying in the design, not A professional obstacle that cannot be miser.
In this stage of development, since it has been dealing with your unfamiliar field, I think some auxiliary design tools seem to play the features that should have. During this time, the maximum of me to me is the company's E-mail system, all the unclear issues, and the answers to the problem are turned around. In other words, in the demand analysis phase, it has played an extraction of the exchange of communications and customer needs. So, in this stage, the E-mail system is the tool for me, followed by Excel, I use it to establish a problem tracking chart, and I need to record each of the issues, put the problem result ( It can be divided into clear, not clear, unclear, have not answered), according to these tables, I can understand the core problems in my work, and have a solution to it, improve work efficiency. .
Every refinement of the first layer, I will deliver the issuance of the entrustment party, and when they make it to terminate refinement, after approximately eight layers, the other party believes that the effect has been achieved and confirmed to end. At this point, the analysis work is complete, and the demand analysis of the project is basically successful.
In this analysis, I think the reason for success is mainly the method and tool selection. In interface design, popular auxiliary tools, providing a lot of help in the establishment of demand and logical model, making it more convenient to help yourself clear thinking. The iterative method is selected, and some errors are corrected in the continuous iteration of functional analysis and interface analysis. In the later stage, when the functional demand is mainly, I mainly dependent on communication tools and table tools. This also shows that the auxiliary tool is not the key to the key, demand analysis, should be communicated with customers.
Through this case, I believe that in the demand analysis of software, the importance of the method should far exceed the use of the tool, and should first determine the risk of the analysis, classify the risk, and solve the various risks in different methods, and tools The choice is not only to see influence and fame, but to truly use it for me, you should grasp the essence, that is, what help can help to develop, not only to use it. I think the role of tools in demand analysis is no more than two: First, the actual system and environment model, etc., the second is the demand expression tool. The representatives of the first category are ROSE, and the second type of representative is Word, WPS, Visio et al, in which the communication tool is used in this project, the web browsing and the E-mail service system.
Finally, I still concluded that the tool methods in the demand analysis are just the factors for the success of the auxiliary project, and the real decision factor is still - a "communication with customers".
comments;
(1) The method and tools are discussed more practical. (2) The discussion of the two types of demand is a bit characteristic, and the method of solving the problem is more successful, and it is convincing. (3) Can express their own opinions and opinions, and experience it. (4) This example seems to be a particularly specialty, or to encourage the project to do projects in the business areas you are familiar with, otherwise, sometimes it will be more than half. (5) It is best to list more items or examples, making the method and tool discussions more comprehensive. (This article mainly refers to the papers of Shanghai Xiangliang and others)
On the Application of Java Technology on the Internet Platform - Papers 1: ERP Development Application
【Summary】
According to the urgent needs of a certain type of company, the information technology company organized a corporate resource plan (ERP) project development, hoping to promote the development of ERP applications, and hoped to use Java technology more effectively. The content of the project involves the whole process of enterprise production and operation in a certain type of industry. Its basic goal is to improve the labor productivity of the company, increase the company's profits, and optimize the resources of the company, so that the overall operating level of the company can last. This is an Intranet typical application project based on Java technology.
In the project, I assume important responsibilities of the project leader. For example, in the preparation stage of the project, I have organized training on the business process of the project group; in the project demand analysis and design phase, I am heavy Considering the framework and prototype of architectural system, the next refinement analysis of the project group and other analysts has laid a solid foundation. At the same time, I also organize the overall group of projects to grasp the onset analysis between the modules, and maintain close communication between the individual analysts. In the development phase of the system, do a good job in developing, testing coordination and synchronization, ensuring the reliability of the system, can successfully advance the project in the implementation phase of the system, and the application after the project has been well received by users.
【text】
Compared with the wide application of international ERP projects, my country's ERP application level has a considerable gap. According to the actual urgency of a certain kind of company, our company organized the development of a class of ERP products. I have been fortunate to participate in the analysis and design of the project, and the results of development are a typical Java technology applied to intranet practical projects.
When choosing a specific technical solution, we have conducted serious thinking and research. For platform schemes that choose a universal Microsoft mode, or cross-platform Java solutions, we have played, because Microsoft's VB ASP has become a scheme that everyone is recognized after a longer time. Java has become an important factor in the fear of fear due to the difficulty of high-quality and low-cost efficiency. However, Java's cross-platform features become more concerned, especially many large and medium-sized enterprises, their existing network systems are based on a variety of platforms, and their cross-platform requirements and voices are extremely strong, and for software In the company, the cross-platform characteristics of software may save development costs, reduce maintenance, and get more customers' recognition. Considering many market conditions and industry development factors, and finally decide must use Java. Fortunately, the development of Java is now more convenient for the development of the Internet.
At present, Java's development technologies on the Internet have been released. There are initial Java servlets, SQL-J, with the database, and JSP comparable to ASP and PHP. Especially the rapid development of JSP technology, making Java's network applications are no longer a small number of patents, and JSP has become the first-choice Internet development technology in recent years with its efficiency and convenience of its implementation. JSP is a page. Development technology, which can easily implement the page in combination with Java Script as its client language as Java Script as its client language. Choose a JAVA and front-end JSP of the backend, there is an important task, that is, the front and rear joints. Since JSP is mainly used for page performance, the content that needs to be expressed is to be encapsulated. In this way, in order to ensure the safety of major business logic, we use Java Bean as a bridge, the client JSP through the Java Bean, complete the main business. Logic function. In the background, the bean is constructed, forming a powerful bean library, and then used by the front desk JSP.
When conducting Java Bean, we will make a big investment under our current project, but it is not only urgent in our current project, but also a strong repository for long-term accumulation in the company. It can achieve a certain degree. Resource sharing and software multiplexing, developing the foundation for other projects. Therefore, the goal of this plan is to form a platform library of Java Bean in Java technology.
We divide these classes into several levels based on the use of the class embodied by Java Bean. The bottom layer is the structure of the parameterized class. The main functions implemented by this layer include universal access mechanisms, and other levels of access interfaces such as databases and public processing systems. The intermediate layer is the structure of the physical class, including the structure related to data information and its processing method, where the focus is to include some important business logic processing. This layer is related to the various parts of the system, and its safety requirements are high, directly affecting the reflection of the main functionality of the system, because the system's main body is handled for some logic, which requires this layer of physical classes to be very serious , Do detail accurate. The uppermost layer can be referred to as an interface class, which is mainly used to achieve the relationship between the underlying class and the front desk. Only this layer can be used by the front desk JSP to use the Java bean call, only this layer has an openness, this layer has an important practical content in addition to the above-described interface function, that is, the front desk. JSP page automatic constructors.
The page automatic constructors herein can be considered as an important feature of the system, and the purpose is to allow users to easily customize the interface without the need to modify the program, which greatly meets the user's requirements. The main contents of the page automatic constitution program include customization and modification of interface elements, modifications, and control of the action of action, and report design and computational summary. The design of the page automatically constitutes the above-mentioned interface class and JSP, using classes to achieve elements customization, control, and association, and save important information, so that the user has repeatedly modified. The automatic constructor provides powerful features that have become our separate products. It can be applied to interface production of various projects, which realizes the goals of our original shared resource.
In the application of the front desk JSP, it is achieved as simpler as possible, so that the system's security can be improved. Of course, in our system, there are still some client control complicated, in order to protect this complicated control script, we take the method of servlet to protect this script, thereby ensuring a certain degree of security.
During the login of the system, we have taken a fairly strict login key check operation. If the user does not have the corresponding key provided by the supplier, it cannot enter the system through verification. Users for trial version provide a valid period constraint. These encryption or security measures, by encapsulating strict and powerful encryption algorithms in Java Beans, they can be passed after the client application is verified. In the process of using this technology program, we have encountered a lot of difficulties. For example, in the previous mention, the requirements for JSP in JSP can be simplified as possible to improve security. Since there is still some of the JSP that is easy to guess the statement and process of processing methods, in order to further improve safety, we have formed a good measures by applying a large number of online information, such as making JSP tags. The library will be probably demonstrated to further planning, and there correspond to generate a set of effective practical tag libraries, which increases a very effective guard, which greatly improves security confidentiality, and makes the page The separation of the structure reached a certain level. Another example: On the processing of data, it always encounters the system operation when the system will become more slower. Finally, the reason is to find out that there is too much data connection, we use data in time. Techniques such as connecting pools solve such problems.
The system adopts Java platform, providing a plan to use Java Bean and JSP, which is quite prominent, and has been well received in the user's real use environment, and running is also relatively stable. Due to the unified and convenient page automatic constructors, the user's interface is very friendly, and can be customized according to user needs to meet the user's adaptive requirements. And in the interior of our company, a set of resource libraries based on this platform has also been established, making it a valuable wealth of the company's future development.
It must be pointed out that in this system, there is still a lot of shortcomings, such as the degree of assembly of the entity class is not satisfactory. According to some common points of the various business logic, it can be further abstract packaging, so that this part of the content can Meet a variety of systems for similar logic. I will further strengthen all aspects of the analytical capabilities in the future work, lead the team to continue to transcend the current level and level, strengthen our team building, hoping to have more excellent software products to write Made in China. (This article mainly refers to Shanghai Chen Lili's thesis)
Papers 6
On the Application of Java Technology on the Internet Platform - Thesis 2: Application of Communication Service Platform
【text】
Data communication is the application field that is currently very active and popular computer and information technology. A large communication company has developed its main support platform, here, we are referred to as "Communication Information Service Platform" for carrying out data business in the country and globally. This platform is a typical Java technology applied to an INTERNET project.
As a technical backbone in the information technology company, I have been fortunate to participate in the analysis and design of the system, and I have a considerable Java application development task. Most of the software part in this system is implemented by Java. In all systems, we use the Java architecture system:
(1) The system can be divided into 4 layers, which is Browser, representing a layer, an intermediate layer, and a data layer.
(2) Indicates the Java Script in Java to implement the page output in Java Script.
(3) The middleware layer uses Java to implement CORBA, which is implemented, which is mainly implemented and reused for business logic.
(4) The data layer is mainly the implementation of the database and stored procedures.
When we apply Java technology, the techniques and strategies used can be generally summarized as the following five aspects:
(1) Make Java Script as simple as possible, because Java Script is placed in the server side in our system, which is performed by an interpreter, relatively slow, we use two HP front machines Run Java Script, but its running speed is still not ideal, so we use the Java Script only to display the data obtained from the middleware layer to generate a dynamic page. In the initial design, a layer (Java Script) has undertaken some business logic processing operations, resulting in efficiency, so we have to reduce the amount of Java Script. (2) When implementing CORBA with Java, sharing and multiplexing should be considered. In this system, the initial design is to make Java when implementing Component, just performing some of the operations of the database table, resulting in a large load of the layer. Later, when we were redesigned, summarize all USE CASE, identify the interfaces that can share and reuse them, and package the same business logic to a interface. Because Java's execution efficiency is higher than Java Script, system efficiency is improved.
(3) In other projects, we have used JSP technology and servlet technology in Java, and the average person may not distinguish between two Java technology. In order to obtain some of the execution rate of the system, we adopted a famous pressure test software - Load Runner to test the difference in these two technologies. Test indicates that the same operation is done with JSP and servlet, and guarantees that the test data obtained in the same test environment (the same server, pressure test workstation and database environment), the test data has a big difference, JSP completes an average of an operation The execution time will eventually be twice as the servlet program. In an enterprise application project, this may be a very critical bottleneck. Therefore, we have concluded that use the servlet as much as possible under possible conditions. Of course, JSP programming is fast and modified compared to servlet, and it is acceptable to applications where access is not very large.
(4) When using Java as an overall solution, try to use the same version of JDK as much as possible. In projects with Java as programming languages, almost mostly encountered "Chinese characters" problem, Java is likely to have garbled when there is no transition. With different versions of JDK, the solution solution is different, such as the V1.2.2 version of JDK and V1.3 version of JDK solutions will be different, put the java program of V1.2.2 in V1.3 In the JDK, the Chinese characters cannot be output smoothly. The root cause is that Java uses Unicode encoding and is different from our national standard coding. Therefore, some people struggled to advocate "one writing, everywhere" seems to be unable to pass all occasions.
(5) When using Java, the software specification should be as follows. There is a concept of JVM in Java, that is, a garbage collector is used in the Java virtual machine, specifically used to recycle memory. But the garbage collector also brought hidden dangers while bringing convenience to programmers. In the programming, the garbage collector cannot be enforced, so developers cannot determine if an object has been released, often let programmers develop bad habits that are automatically collected, so we request: After try, Catch must be clearly required Recycling memory (of course, can only be notified of garbage collector to recycle garbage), which effectively improves system stability. The technical and strategies of these practical properties are some practical experiences in practice, only for developers based on actual conditions.
Of course, when using Java as a solution, there will be a lot of problems that make us headache. These problems have caused concurrent concurrency and the system speed is slow. In summary, the main specific issues we have encountered are:
(1) Use Java to implement Component in CORBA, and sometimes the efficiency will be relatively low.
(2) Establishing a database connection with Java is often slower.
(3) It is easy to lead to the spread of system information when programming with JSP. For example, if there is a hacker attack a server running a JSP program, he can deliberately enter some illegal characters or exception information to the JSP program, so the program execution will appear. At this time, the corresponding error message will be printed on the page. Unfortunately, this information is very likely to expose the version number and path information of the JDK of the server. This is often easy for hackers to organically multiply, and it is possible to seize the loophole of the system.
After discovering these problems, we have carefully studied some solutions. such as:
(1) Since it is relatively slow to implement Component with Java, we try to reduce the amount of business logic executed by Component. Strive for the operation that can be implemented in the stored procedure and implement it as much as possible during the stored procedure. It is well known that the stored procedure operation of the database is much faster than executing database operations in the Java program.
(2) Since it is slow to establish a database connection with Java, we can encapsulate the database connection into a connecting pool, so that system efficiency can be greatly effectively improved. We have also used "Load Runner" for pressure testing, using the connection pool than the speed of the connection pool is 3 to 5 times faster.
(3) In order to deal with the JSP program and the servlet program print out the problem of exception system information. We have annealed a lot of JSP or servlet, eventually no hair. But we can change another idea, that is, do not start from the program, and start from the web server, we can configure the Apache to make such exception information no longer print, but make it only a universal unusual description This problem can be solved very effectively.
Most of them are successful in so many projects we use Java as programming languages. As a fast, stable computer language, it is quite stable and compared to developing Internet applications.
In my personal opinion, Java's application prospects are very bright, which can generally focus on the following:
(1) There will be a wider application on the Internet.
(2) In the embedded device, Java is also useful in Wudi. For example, in the latest Java technology, Java has entered the mobile phone field. (3) Most of the Java program runs with threads, accounting for less resources, will gradually replace ASP and CGI programs. According to third parties, it indicates that the JSP program is more than 2 times faster than the ASP program. Use JSP instead of ASP should be a general trend.
(4) The application in Java in the wireless Internet will be more extensive. Java supports WAP, which can easily develop WAP programs in Java, implement WAP applications.
(5) The seamless connection of Java and XML makes Java have a great advantage in data transfer and heterogeneous network communications.
In someone in person, I will work on the application of Java in the wireless interconnection in a quite period of time, and have developed more excellent practical items for my country's mobile communications..
Comment; have practical experience after participating in a large project. The full text has been used in 1, 2, 3, 4, and the style of the article is monotonous, and it is not very attractive. However, the advantages of this article are; (1) It is very organized. (2) Selection of content is appropriate. (3) The strategy listed, the concerns and discovery issues are realistic. (This article mainly refers to Guangzhou Wang Haibo et al. "
Papers 7
On the Application of Java Technology on the Internet Platform - Thesis 3: Banking Application
【Summary】
The increasing popularity and deepening of Internet applications, providing a broad activity stage for Java technology, and also greatly advised Browser / Server mode of corporate intranet application and network computing.
As a technical backbone in a information company, I have been able to undertake a development task such as a bank credit management and inquiry system, independently completing the system design, class design, partial development and testing.
The entire system is fully designed in accordance with J2EE standards. The front interface applies JSP technology. The control section uses servlet to develop, and the business logic applies EJB technology to encapsulate. The application server uses the WebLogic, which supports J2EE standard BEA's WebLogic. The database is INFORMIX 7.3, the purpose is to Keep consistent with other business system databases in the bank. On the hardware platform, we choose a medium-sized server machine for HP, and the operating system is HP-UX.
The system interface is applied to IE, which is not only compatible, but also is familiar with the majority of users. After the system is running, the various branches are generally reflected in the world's friend, powerful, and the effect is satisfactory.
【text】
Private savings in bank applications, business accounting, international business, credit, financial management are all important, and they constitute a bank's basic business system. The credit business I have developed is an important part of the source of bank profits. Different with savings, business models mainly based on trading matters, although credit is also transaction, but more other auxiliary information is required. Such as the basic information of the customer, in the business situation, credit rating, whether there is overdue loans that fail to return. All branch of relevant business personnel and branch managers want to be able to understand this information in a timely manner. The traditional terminal-based user interface is difficult to pass so much information to the user, so we decided to adopt the user interface based on the beta IE. On the one hand, IE uses easy to use, no special training, and it is bundled with the Windows operating system. It also saves the front desk fee. There is ASP in development technology, and JSP is available.
Since Java technology has developed rapidly on the Internet, J2EE has put forward a new idea to unify platforms, so we decided to adopt J2EE standards and selected JSP. In the design, it is basically a transaction screen corresponding to a JSP program, and gives full play to the strength of the JSP dynamic processing page. In order to make the design have better exparative, flexibility and logic, it can lay a solid foundation for future expansion, I use the MVC design mode of Modelu, View, Controller, and the View is implemented by JSP, while Controller It is a servlet program that is responsible for handling all the requests transmitted by the front desk, and distributes the corresponding JSP program to process according to the predetermined path / program relationship. Since servlet is designed for Java server-side programming, it is quite appropriate by it to be responsible for server-side processing.
When you start design, I use the component technology, and the EJB assumes the Modelu role of the design pattern. Specific loans account, lending, surplus loans, returning loans, etc., there is a specific EJB. In order to separate these processing logic to the corresponding database operation, it is more convenient to maintain, and I will handle the EJB of the service to session beans, and the corresponding Entity bean is used to access the background database. . It is important to inquire, according to the results of demand analysis, and the goal is to increase the speed of the query as much as possible.
In the access to the database, I originally designed the Driver Manager belled in Informix JDBC, so that Driver and Server write Driver and Server in the BEAN in the access database, and later considering that the platform should be used independently. After seeing the instructions of the JDBC part in J2EE, the Data Resource method is changed, so that even if the database is replaced in Oracle or other products, the program does not have to be modified, only need to change when configured.
During the development of this credit management system, Java's platform was unrelated, and it was performed in the activities developed in development. Due to the relatively shortage of funds, our development environment is a HP machine for each project group. Although each development team has built its own environment, there are more projects, especially in the event and bulk test, the machine It is obsessed that the efficiency of development and testing is greatly reduced. Since our team is Java technology, our group can build the same environment on its own NT machine. In this way, everyone usually develops, including JSP, servlet, EJB program, can be done locally, just to put it on the HP development machine to the test or presentation phase.
Web applications we developed before, often applied part of Web technology, such as adopting Apache Web Server, ASP development language, etc. The integration and combination of the entire system is often undesirable. This time because of a complete set of J2EE standards, the synergy and consistency of the entire system are very good. Coupled with an application server that supports J2EE - Bea WebLogic, we have done an unsatisfactory complicated configuration, and the inter-module is not worried, just in the graphical configuration tool, enter The configuration required by the system, such as the relationship between the path and the actual application, EJB reference in the component, Data Resource, etc. After all configuration is complete, WebLogic will complete the deployment of the project for us, and package all the related programs package stand up. It turns out that the documentation task of our development group is very heavy, because the entire system has both transaction section, and there are many management inquiry, transaction, and data and source programs. In order to solve this problem, we directly applied JavaDoc export documents in the Java source, not only the text is beautiful, but also keeps the consistency with the source program, it is a stone two birds.
After the entire project is complete, the user feels friendly and easy to operate. But I know in my heart. There are still many ways that can be improved in this system.
First, based on the development of the Java system requires more funds, the system is limited by the system, only the production machine is applied, so that Web Server, Application Server, DB Server can only be crowded together. Although WebLogic can achieve partial load balancing, such distribution is definitely not the most ideal in future business development. Fortunately, we have considered good scalability while designing, in the later conditional permit, only further deployment between different machines can be made, and the application is generally no longer need to be changed.
Second, in the design, UML products can be used, such as Rational Rose, on the other hand, Rational Rose has automatic code generation functions, or greatly saving costs.
Finally, the current amount of credit management system is not much more than the number of users. When promoting similar systems requires a large number of users, Java-based system-based response time and system distribution will have a more prominent contradiction.
These are all where I need to pay attention in the future system design and development, and it is also the direction in which Java technology should work. (This article mainly refers to the paper of Shanghai Dai Ling Pan.)
Comment: Discuss specific, deeper application, clear expression. The problem is true.
Papers 8
On the Improvement of Web Server Performance - Thesis 1: Banking Application
【Summary】
Web technology-based database applications are a hotspot for current applications, and improve web server performance is an urgent topic in applications where users are large and communication load. This paper has been taken from the author's experience in the development of a bank system project. It describes the performance of the improvement of the performance of the web server should penetrate into project arguments, selection, development, operation and management. Only all aspects can fully consider performance and quality. The need, the performance of the system is truly guaranteed and expandable.
The article from the actual operation of the system and the corresponding experience, the article explains some specific measures in performance improvements.
For example, in this article, the selection consideration of the web server platform is discussed; the configuration management of the web server; the application system itself is optimized and the performance guarantee of expressed performance when designing the system.
Through technical analysis and improvement, multiple types of measures and means are combined, in actual systems, the performance of the web server is guaranteed to be guaranteed. 【text】
My unit is a information technology company that targets the development of IT applications in the financial sector. With the development of financial electronic construction and the intensification of market competition between commercial banks, major commercial banks continue to provide new financial products through information technology, and hope to integrate market channels. For example, the main commercial banks continue to launch a variety of online banking services. In this context, I participated in the development of a new generation of online banking products, involving providing online personal wealth management services, online foreign exchange services, online business services, etc. have market competitive products. As one of the organizers developed by the project and the main technical backbone, it is always in the first line throughout the project development, thereby improving the performance of Web server, improving the overall online platform system performance, briefly discuss this article As far as you want to share your experience with your readers. In terms of Web Server Configuration and Optimization, I have the following main experience:
The first aspect is the web server selection consideration.
At the beginning of the web server selection and online platform, we have fully considered the performance and scalability issues of the entire online platform. This considers a solid foundation for the stability and expanding performance of the system.
Some online products of a bank have been developed earlier, so it is the way to call the old HTTP Server CGI program. At this time, each customer request needs to process the system process of the backend system to run the CGI program. The system's overhead is quite large, the system's extension ability is also very poor, and the performance can no longer meet the needs of business processing, so it is When the banking system is specifically selected, we reject this solution at the beginning.
Through the comparison of similar products on the market, we chose the IBM's Web Sphere Product Series of International Business Machinery Co., Ltd. as the establishment platform of the bank online banking system. This choice is because Web Sphere is based on the overall architecture separated by the HTTP Server and the application server, while supporting the light level thread specification such as JSP, Servlet, and Enterprise Group Java Bean, all requests correspond to processing threads, systems on the application server. The cost is low, the efficiency is very efficient, and the web sphere is equivalent to the entire architecture. It can make different horizontal and longitudinal extensions for adaptation of extended needs, so that the future expansion needs of banks can meet the future of banks.
It is precisely because we have considered future expansion needs, and the entire system in the next several performance improvements, we can generally achieve the expected goals relatively smooth.
The second aspect is the performance configuration of the web server.
When the system is on the first system, since the system's load is not very large, in order to save the system total cost TCO investment, we have put into production of the system on a lower configuration IBM RS6000. The HTTP server, application server, communication server, etc. of the entire system are located on the machine. Since there are not many users in initial production, the performance of the system can basically accept.
However, as the business development and the increase in user visits, we found that the server's response is slow, and the CPU utilization rate of the system is significantly increased. After tracking, we have found that one of the key reasons is the insufficient memory of the system. Since the online server stores a large number of users' session information to supply the application in memory, when the memory is insufficient, a large SESSION information is forced to switch to the hard disk, and a large number of CPU time consumes the exchange of internal and external, the system efficiency is rapidly decline.
In view of this, we extend the memory of the server from 2GB to 4GB, while adjusting the save time of the user session information, so the efficiency of the entire system returns to the ideal situation.
Since the continuous production of new applications and the increasing database operation, we will gradually monitor the system's database in a busy state, and the system's error log also records the shortcomings of the database connection used by the supplied server. In this context, we believe that the entire system should be horizontally extended due to the hardware configuration, so we separate the database server, configured to another higher performance server, the corresponding database resources have also increased significantly, so The performance of the entire system is in a more ideal condition. The third aspect is the corresponding optimization of the application system to improve performance.
Web server configuration and corresponding hardware expansion is not loses a shortcut to resolve system performance issues, but the optimization of the application system should also be considered, after all, it can improve the system's application efficiency.
In the early days of development, we have a very payment of the utilization efficiency of the system, such as reminding programmers try not to use user session information (session) to pass large objects, and pay attention to recycling for memory. At the same time, through internal communication will promote some small, useful programming skills to improve the level of developers, through the spot check, I hope to find problems in the early days.
During the system run, we found the Java virtual machine based on the application server. The free space of the memory stack has a continuous decline. It will be exhausted every few days, and the new object space cannot be allocated. Restart. In addition to the reasons for the problem of the system itself, we have identified problems with the development of the application system. By monitoring the Java virtual machine from the Internet to detect the Java virtual machine to monitor the JVM, there is finally discovered objects that cannot be recycled in the system, and then find the corresponding program to discover the "annular" object reference in the program. Resulting in the use of the garbage collector after the object is used. Although the resolution process of this problem is very difficult, since this issue cannot be fundamentally resolved by upgrading hardware or increasing resource allocation, it will bring a lot of hidden dangers to the system. Therefore, the analysis and solution of the whole process is completely worthwhile, let alone through the process of finding the cause of the fault, giving a vivid software quality assurance class on the entire project group, has greatly promoted the quality of the quality of the project team.
Therefore, it is said that the performance well of the Web server is not simply system management, it penetrates the development and
A series of steps such as system operation.
The fourth aspect is pre-considered for future expansion and performance needs.
With the development and maturity of the system, considering the continuous rise in user access, in order to reserve the development space of the system, we have recently made a systematic upgrade for the entire system. Improve the entire system throughput and single-point fault over service by introducing multiple HTTP servers and applied server parallel work. Since the need for dynamic load balancing and horizontal expansion of dynamic load balancing and horizontal expansion, this upgrade does not require fundamental changes to the architecture of the entire system, but also caused the application. Any impact.
The entire project lasted for nearly two years, from the system of these two years, the entire system is successful. Based on my personal experience, system performance is not simply issues in system operation and management, but penetrates at various stages of project argumentation, development and operation. Only at all stages can be fully considered in the performance of performance. When actual operation, the performance of the entire system may be truly guaranteed. In terms of technical perspective, a series of means such as selection evaluation, hardware extension, application optimization, and system configuration optimization can be used. For example, in hardware expansion, it can be divided into main components expansion, longitudinal upgrade, lateral upgrade. In our project practice, the various means of the above have been combined. For example, the entire system of a bank is less than 10,000 days of visits from 10,000 to now more than i.0 million, the performance guarantee and improvement plan of the entire system is successful.
Comment: The practice process is more convincing. The advancement of the provision and thinking is quite clear, the advancement of technical measures and management measures is also clear. There are still some limitations discussed, and it is not open enough. (This article mainly refers to the papers of Guangzhou Huangzhou and others)
On the Improvement of Web Server Performance - Thesis 2: Application of Digital Library
【Summary】
A large and medium-sized library information system involves many technical and programs, this paper focuses on some of the content related to the performance of the web server.
I am very fortunate to participate in the design of a large library digital information system and based on the development of Web applications. Since most of the digital index, information, information, image or audio video, etc., have a high demand for web server performance due to most of the digital index, abstracts, full text, image or audio video.
Combined with the experience of actual engineering, this paper will be implemented from hardware implementation (cache server, balanced load equipment, web dual mirroring, CPU and network card upgrade, network bandwidth expansion) and software implementation means (three-layer C / S software structure design, application Two generous discussion of program deployment) How to improve the performance of the web server in order to enable users to use the application system faster, efficient and safely.
【text】
With the development of intranet information technology, the library's digital informationization project is also imperative in order to better exert the functions of its book circulation, data retrieval and academic exchange. A library has launched a part of the digital library project in order to step into the ranks of the World Advanced Library as soon as possible.
The digital library project mainly includes external information web distribution system, interactive search network, background housing information management system, multimedia data acquisition and production, and VOD on demand system. I am fortunate to be one of the project leaders, participated in the overall design of the entire digital information system and participated in the development of some Web-based applications (such as external information distribution systems, images / full-text hybrid retrieval systems, VOD on demand systems).
A library digital information system speaks from a network environment, mainly divided into multiple network segments: (1) Intranet access section, using 2M DDN line; (b) public network segment (non-military zone), mainly including reception release Database server, web server, e-mail / ftp / DNS server, retrieval server, and SAN network area storage device; (3) is an internal local area network, including an intranet web server, a background library database server, an OA server, and more. (4) It is a VOD on-demand network, including audio video on demand servers. Due to the development of strict network-level and application level access, the anti-question reliability is effectively controlled by high-performance switches and security authorization certification systems with three-layer exchange capabilities, ensuring data security and integrity. Considering the quality and future maintenance management operations, the operating system uses a Windows NT platform, the server selects the Dell high-end series, the database uses IBM DB2. The main network is a Gigabit fast swap Ethernet, the local area network is 100 megabytes to the desktop, and the VOD is overcast.
In this network environment, the application is mainly divided into three parts: (1) external Web distribution system, external book auxiliary search system; (2) Background hub information management system and image / full-text hybrid retrieval system; (3) VOD on demand system. Due to the vast majority of the Browser / Server mode structure, end users only need to install IE or Netscape Web browser locally, request and access all kinds of application services through web pages in the support of the background database server. In addition, due to the multimedia information such as index, summary, full text or audio video, which is flowing in the library information system, has higher requirements for web server performance and network bandwidth.
By continuous experimentation and practice, we have found that the Web server performance can be relatively effective from the following aspects; (1) Cache server and balanced load devices can mitigate access bottlenecks, improve network bandwidth, and implement balanced loads.
Cache server is also known as the Cache server, can store Cache static content such as web pages, multimedia on-demand resources, and conference live (compressed, have a format required), etc. In addition, the current US Cashflow cache server can be stored in dynamic content such as Cache databases, ASPs. The Cache server is typically placed outside the firewall. Before the external network web server, the Internet user clicks on the web page no longer directly access the website web server, but an access to the Cache server.
Since the Cache server has multiple CPUs and high-speed large-capacity I / O channels, separate OSs, can greatly alleviate the Internet access bottleneck, and also have a certain ability to attack anti-hand attacks.
At present, a library uses this way, putting the quantity picture, on-demand resources, virtual 3D applications, etc. in the Cache server, even if only 2M Internet access bandwidth, play speed and effect of the above application Can still be satisfied with users.
Another way emphasizes a balanced load device or a web dual mirror image. This method achieves optimal Web access performance through load balancing methods. The web dual-machine mirror is an earlier mode. Although the system reliability can be improved, since the dual-machine is always interrogated to each other, it will affect certain access performance. Balanced load devices are hardware that is independent of the web server, and other servers in the web server and other servers are connected to the same switch. Through the load scheduling program, it can achieve the full use of resources, improve access performance. . Just because a library currently publish resources relatively small, only three web servers are used, so the current balanced load equipment is not significant.
(2) From the configuration of the web server, the number of web servers itself, the number of network cards, the number of webcards, the location of the web server and the firewall will affect the performance of the web server.
From the web server hardware itself, the number of CPUs increases, the number of network cards increases, and the I / O channel extension can undoubtedly improve the web server performance. In addition, since the Gigabit firewall is currently less and the cost is high, if the web server is placed, it will greatly affect the Internet access performance. A library adopts IDS (Intrusion Detection) web server (server firewall, lower end, no traffic) application server database server (firewall, high-end), and hierarchical security mode guarantees the security of the system Sex, improve network access performance.
In addition, a library also uses SAN network area storage to improve server access speed.
(3) The appropriate deployment of the three-layer C / S software structure design and application will also improve the performance of the web server.
Separate business logic, universal access interface, and data, etc., are placed on a web server, application server, and a reasonable deployment of program functions and logic, can also greatly improve Web server performance.
The general principle is that the web server only needs to accept Internet HTTP access requests, so that the Web only has the least task, handle the actual processing to each application server process, and then return the result to browser. A library uses this way to develop search engine application servers and hybrid retrieval applications, and achieve good application results.
In fact, there are still many ways and methods for the performance improvement of the web server, such as the relationship between CPU and storage, and Web switches, etc., which needs to be further practiced, analyzed and discussed. (This article mainly refers to the paper of Shanghai Tong Yin and others). However, the techniques discussed should be more organically combined with examples of the project.
Papers 10
On the Integration of Real Time Control System and Enterprise Information System - Thesis 1: Communication Industry Application
【Summary】
In recent years, under the powerful driver of application needs, my country's communications industry has made great progress. Many enterprise units in the existing communications industry, such as telecommunications companies or mobile groups, one of the main features of their information systems is that the real-time monitoring requirements of the line are high, the amount of data is huge, how to integrate real-time control and information systems. Become a key part of the system implementation.
After participating in a network management system of a communication company and the design of the decision support system, we analyzed the integration and application of the two, deeply felt that there is a good design strategy and paying attention to the tools selected. . This project is mainly for real-time monitoring of subnet subnets and related links in communication, implementation alarms, routing control, and authorization, etc., the key is to provide a real-time map interface, and the well will summarize data Organization, establish a data warehouse and further implement data mining analysis, thereby supporting business decision analysis. As one of the designers, I focus on discussing the policies of the control system and information system integration herein.
【text】
As we all know, the communication industry needs a means of monitoring the communication network. Its work is characterized by the distribution of each sub-station and base station in geographic location L, more need to provide different sub-link links in higher levels. means. Generally speaking, since the data is massive, how to deal with the data obtained throughout the network system, so as to combine the analysis of the decision-making department, it has become an important topic that urgently needs to be resolved. Briefly, distribution, real-time, and data massiveness are the core issues of the entire system design and integration.
First, let's discuss "NMS monitoring system". Since this system I have participated in design and development is not located in the basement of the base, it is positioned in the host communication data of each sub-station (including data traffic, link load, communication between the host, etc.) Collect, so the underlying operation requirements for specific communication transactions are not high.
Taking into account the above reasons, we use a geographic information system development platform MapInfo and use Delphi programming, with SQL Server database in the background (this is because of Microsoft's OLAP Service). Before analyzing and planning, we have made detailed discussions on ITU801 standards. This is just a standard for subnet and link definitions and layers. After listening to many sub-staff recommendations, MapInfo provides company A related MAP X Active X control is embedded in the Delphi program, using the rich classes and operations provided in Map X, such as Object, Layer, etc., well, and join the concept of subnets and links, The sub-station under the subsection becomes a different subnet, and the enlargement and narrowing function can be enrolled in a map of the entire region in one map, and can be displayed on the screen. At this time, it is only displayed Summary of each sub-station, small to the cabinet of a host, the cabinet is until the plugin board (because these must be monitored in real time). We use layered methods to achieve the above zoom. For some static data, such as sub-station, the position of the host, first use MapInfo's set of geographic information (MAP X is an Active X control provided to programming tools) to place a static hierarchical diagram. In the database.
Our new system is connected to the dedicated lines of each sub-station, can be used in real time, displayed on the map, reflecting the real-time state of each station, each subnet, and each link, and can control Command back the sub-station (such as forced link interrupt, routing conversion, etc.). Now let's discuss the most critical issues, that is to integrate real-time control systems with enterprise information systems, our ideas and architecture can be generally used in a simple map (here.).
In this architecture, detailed data is retained by each sub-station. The network management system will make a sum of data to the data in a certain time interval, and the contents that need to be saved are put into the database, such as traffic, one minute Station and other sub-station communication traffic, load a link in this sub-station (these links may be dynamically assigned, or may be a communication link between fixed slits). Despite this, the data is still massive, so if you want to send these data directly to each decision department, it is unrealistic to give the market sector. Therefore, we have established a data warehouse on the basis of the database, determine the topics of several data warehouses such as customers, time, traffic, billing, and faults, and prepare the original data in the database every other time. Handling work, establish a good data warehouse. The pretreatment here includes a number of aspects, such as data to establish computational time, but no data (accounting value zero), should be considered to establish failure invalid data, need to be rejected; some companies rent It is a special line based on monthly, and the intermediate communications therefore there is no some relevant records that should be excluded.
After pretreatment, the data fusion and summary will be used to use the OLAP Service. According to the needs of the decision-making department, provide corresponding data (such as: market sector requires every sub-station earning, customer distribution, customer cost, etc.). These can be pre-processed by the OLAP Service, and the processing over the process is logically existing in the form of cubes (Cube), and the storage space occupied is significantly reduced, such as 20 million in August 1999. Bar communication record, even if the text as a backup requires 4G space, only 200M left and right space is processed after the OLAP Service, therefore, the processed data is mainly stored in the machine of another relevant department, and cannot be placed with the primary server Together.
Finally, the system used by decision makers will be discussed. Since these departments are not scattered, we do not use OLAP Servce's Web Publishing Plan. Using Delphi, client software that accesses OLAP Service is used, and the Cube Browser control provided by OLAP Service is used, and various operations of data cubes are provided with interface-like interfaces, such as drilling (observation angles) and even the year ), Slice, rotation, etc. In order to facilitate the output print data, it also embeds Microsoft's Excel PivotTable, which can be converted to Excel's form, or converted into pie charts, column charts and graphs, etc. For example, you can observe the distribution graph of 24 hours a day, you can find that there is a reduction in communication flow after 12 o'clock in the night, and the decision-making department can develop certain offers or reduction measures to attract more customers to use the network after 12 o'clock.
In addition, when the data mining function in OLAP Service, the two types of algorithms provided are based on the classification of decision trees and the clustering of decision trees, and the clustering algorithm of the market sector will aggregate according to the cost of fees, and discovery The common characteristics of customers in the same consumer level, facilitating the development of policies, attracting customers. This effort will continue to continue to ensure sufficient massive data and discover the laws. After running throughout the system, a series of work such as data acquisition and data processing is periodically automated, and the system application has been received for a lot of praise. Of course, there are also many problems, such as the capacity problem of the primary server database, the communication efficiency of the primary station and the sub-station, and the determination of the network fault in the network management system is not meticulous, and it is necessary to Confirmation is determined that there is still a lack of direct communication methods between decision systems and network management systems, which have further resolved and improvements.
Real-time control system and enterprise information system integration is an important driving force for enterprises and institutions engaged in manufacturing, measurement and monitoring, etc., and improve work efficiency. If it is a large company, there is a need to have a complete set of systems, support web publishing, intelligent query, automatic identification such as fault prediction and data mining, etc., so that the underlying real-time monitoring with high-level decisions are better integrated together. Looking forward to their prospects, it is undoubtedly very beautiful, but we believe that the corresponding workload is very large, and it is still necessary to improve and break through.
Comment: The topic of integration can be combined, combined with practical discussion. The database and data warehouse technologies discussed in line with the direction of enterprise informationization. Examples of the problems encountered are not enough, and the discussion of real-time control can also be more detailed. (This article mainly refers to the papers of Guangdong Lin Jiayi et al.)
Papers 11
On the Integration of Real Time Control System and Enterprise Information System - Thesis 2: Application of Industrial Automation Reconstruction
【Summary】
This paper discusses the integration of real-time systems and information systems as an example of an information transformation project. I have participated in a medium-sized modern production enterprise digital transformation project, which has four automated continuously working kiln, as well as the kiln of 8 automated clearance, and multiple semi-automatic medium-sized auxiliary machines. The company hopes to realize these devices, and focus on establishing a central surveillance room, can implement two major tasks of the operating status parameters of the equipment, the former is used to prevent accidents, the latter can be used to the company Decision makers and technology development departments provide information.
Through our development group, our development team works with the company, divided into four steps to complete this work. The first step is to realize the digital output of the device status parameter; the second step is to establish a supervision and recording function of the central monitoring room; the third step is to improve the control function of the monitoring room and the output of the corresponding signal; the fourth step is to achieve production equipment automation The digital signal access function is controlled.
I have three aspects in the main work:
(1) Bridges in the company development group and enterprise interlass;
(2) Responsible for determining the division of labor between the parties in the project, making a corresponding specific solution when conflicting or problems;
(3) Help to solve the difficulties and coordination of various difficulties.
【text】
One of the fundamental ways of modernizing the development of production and improving efficiency is the process of accelerating informationization. In the professional production area of all, this company I am involved in the development project can believe that it has been a considerable level of modernization, such as 4 automated continuously working kiln, 8 automatic clearance work Kiln and multiple semi-automatic medium-sized auxiliary machines. However, the automation control of these devices mainly relies mainly in an analog control before transformation, nor does it have records, summary and analysis functions of information and data. On the one hand, on the one hand, for future development needs, I hope to record the changes in the continuous state parameters in the work process, there is a log and history to provide it to its technical development department, as product quality improvement References in the reference; further providing a reference to the corporate management department decision analysis. On the other hand, companies hope to have comprehensive supervision and certain emergency control and strain of emergency control and strategies to prevent accidents, or prevent accidents for operational accidents and unpredictable events. Loss. According to the requirements of the company, combine the funds, time and personnel of the project, we will then consider the business situation of the company, the market and prospects of the product, the risks of the project development, and after careful analysis, draw The following four opinions:
(L) Due to the restrictions of funds, it is quite important to save costs on the respective links, so it is necessary to modify the original facility and conditions, rather than conducting a fundamental substitution;
(2) This company needs "preliminary integration of real-time control systems and enterprise information systems", rather than a systematic and complete system, which does neither the ability and conditions of developing such a system, nor With relevant personnel of management and application advanced integrated systems, the objectives of the project should be engaged in the overall requirements of the enterprise under current conditions. This is advantageous for controlling costs, and it is also conducive to reducing project risks;
(3) Due to the production of the company and the restrictions of funds, the project must be carried out in phases. It is generally divided into the following four phases: 1 Implement the digital output of the device status parameters; 2 Establish the supervision and recording function of the central monitoring room; 3 improve the control functions of the central monitoring and the output of the corresponding signal; 4 to achieve production equipment automation Digital signal access function;
(4) Most of the people involved in the participation of the two sides are not intensive, and therefore, it must be determined to determine the clear division of labor while strengthening each other.
The above four opinions have obtained the agreement of all project participants in both parties. The two sides must understand and follow the criteria in the development process of the project.
In the first phase, we conducted automation transformation of a semi-automatic medium-sized auxiliary machine. In fact, the company has this kind of intend to have the corresponding technical reserves, so this part of the work is fully responsible by the company's own technical personnel. All automated production equipment involved in the project have the ability to control the status parameter analog semaphore, for the collected state parameter simulation, the company has planned to use a class to remotely transmit to the central surveillance room , The scheme of modulus conversion. This program is relatively simple to business, but there is a high cost, and the remote transmission process is prone to interference. With the significant decline and reliability of the analog-to-digital conversion equipment, the company is determined to achieve field analog to digital conversion on the ground of the production equipment, and far away from digital signals to the monitoring room. One work is also implemented by the technical staff familiar with this technology.
The second phase of the work is mainly responsible for the members of our development group. We divide people substantially in 3 groups. The first group is mainly based on the long-term data of the company and the public published technology, including intervals such as data sample records, different production stages. The relevant content of data processing such as mathematical model used in data processing; the second group is responsible for monitoring the input output interface of the record software, the selection and design of the user graphical interface, and the third group, the power is concentrated in writing one Simple and practical, targeted and compact related data records for dedicated databases. This phase is a key stage of control quality and cost. For the consideration of cost, and the traffic is not very high according to the traffic, the real-time processing requirements of the data are not very high (usually, the real-time control of the equipment is still under the actual situation of the original automation system), central monitoring The room uses a server with a dual-machine backup as a server for data processing, and another server is equally two-machine backup servers as a database server, and does not use a price expensive commercial database, and an economy developed by itself. Practical private database. The third stage can be seen as a natural extension of the second phase. On the basis of successful second phase, the data obtained after the second phase of the module is processed, according to various critical indicators of the device, the corresponding judgment is performed, allowed In an emergency, the corresponding alert is issued, and the control signal is issued in accordance with the corresponding emergency treatment of the device itself. The key to this stage is two aspects: a problem is that the data conversion device has a relatively high reliability and usability, and another problem is to pay attention to cooperation with the self-protection function of the original control system of the automation equipment. .
The fourth stage is still implemented by the technical staff of the company. It is mainly to solve the above two key issues encountered in the third phase in the implementation process. For the first question, a better device and component are used to implement digital-to-mode conversion and dynamic control; for the second problem, priority judgment is set in the control device, so that the start-up priority of the self-protection device leaves the center The monitoring room (due to the speed of self-protection is faster, but the function is weak).
From the perspective of the total project implementation, one, four two phases are connected, two or three two phases are connected, and between them can be carried out in parallel, thereby meeting the requirements of time schedule.
In the future, this type of technology used in this project may have to go to fully automate. The amount of data involved in the project will be much larger, and the real-time requirements will be higher. We should pay attention to how the existing mature business systems and products are applied thereto, making it possible to meet the requirements of the enterprise as soon as possible, save costs, and reduce the development of the risk.
Comment: This project initially realized the first phase of production control and information system, and the project realized the target, and the effect is directly. The background of the project is written in the work of the project and the author's work, and the body is clearly listed in the policy, the process and the main technique of the project implementation. (This article mainly refers to the paper of Shanghai Shen Zi respect and others).
Papers 12
On the Integration of Real Time Control System and Enterprise Information System - Thesis 3: General Application of Industrial Control
【Summary】
Through the development of the "Industrial Control Configuration Software" project, this paper focuses on the integration of real-time systems and information systems. In recent years, the configuration software at home and abroad has achieved great development and has been widely used in enterprises. The configuration software uses a real-time database as a core technology, integrated technology such as industrial control, network, graphics processing and database access interface. It is a kind of software product with high technical content, with good application prospects and market potential, there are many Information technology companies are developing industrial configuration software.
I have been fortunate to participate in the project, in which some of the projects are analyzed and designed, the software adopts the Windows 2000 operating system, mainly using VC6.0 development. Hereinafter, from the characteristics of the configuration software I have developed, the software architecture design, real-time database design, expansibility, and maintenance design, and project implementation management are discussed. 【text】
Industrial Control Configuration Software has a wide range of applications in the industry. Such software allows users to control various sampling points, process output points, equipment, production workshops, control loops, documentation, and production reports, and reports under the graphical interface. Control strategies, network devices, and production process screens are defined and configured. When using this class software, users can even form their own control system without writing a program, and some powerful configuration software can provide connection functions such as the network, Internet, database access interfaces, so that the on-site control system can be relatively Conveniently and the company's information management system integrates, a information technology company decided to develop new new industrial configuration software, as a technical backbonate, I actively analyzed some of the tasks of analysis and design in this project, the software adopted The Windows 2000 operating system is mainly developed by VC6.0.
This article will discuss from the basic characteristics of the configuration software we have developed, the software architecture design, real-time database design, expansibility and maintainability design, and project implementation management are discussed.
l. Basic features of the configuration software I have been engaged in
Through analysis of the characteristics of domestic and foreign configuration software and current technology development, I think the configuration software we started to develop should highlight the following three characteristics:
(1) "Real-time and Reliable" is the premise of such software to survive, but there are still many configuration software can't do this.
(2) Good network network network networking capabilities and distribution functions.
(3) Effectively use ODBC (open database connections) to facilitate integration with other information systems.
This project should focus on the design of the architecture of configuration software and the design requirements of real-time databases should focus on the functions of similar software at home and abroad, and the truly excellent software can be generated by comparison and identification.
2. System architecture of configuration software
This software uses a three-layer architecture that has open and good expansion.
(1) The bottom layer of the software is the hardware access control layer. This layer is the OLE for Process Control technology in the previous year. The advantage of using this technology is that OPC is Microsoft's standard interface technology, with numerous hardware manufacturers support, the OLE used Technologies make software good adaptability and expansion capabilities.
(2) The intermediate layer is a real-time database. This layer is the core of the entire system. In addition to the characteristics of the general real-time database, the layer should provide two types of interfaces for the application layer: First, the application programming interface API (such as DLL is implemented), and the other is ODBC. Interface, the interface makes the system good openness for system integration.
(3) The upper layer is the application layer. Access the database via the ODBC interface, you can query the data of the database via the SQL statement.
3, this project involves real-time database design
In design, we focus on the following four aspects:
(1) Basic functions of real-time databases: Real-time database completion of the acquisition, output, alarm file, etc. of real-time databases, and management of historical data.
(2) Real-time design: Since the operating system used in this system is Windows 2000. Its real-time performance, so the task management timer must have good real-time, when designing, we use a high-precision timer that seizes the service to a certain extent, ensuring that the system has good real-time.
(3) Task Scheduling: The goal is mainly to make the system to achieve the equilibration of the ideal load tasks in each time.
(4) ODBC interface design: Development of corresponding drivers, implement ODBC functions, so that it fully complies with SQL conventions, which allows applications to develop means and development tools, allowing VC, VB or Delphi, etc. Language also makes the database have good openness. However, the SQL statement does not implement the selection of data time, affects real-time, so the system automatically adds timestamps to each database, SQL can pass timestamp to perform time control to select (read) data, thereby meeting real-time Basic requirements for sex.
4. Scalability and maintainability design of this system
The configuration software combines a variety of technologies, and its architecture and data structure are more complicated. In addition, we hope that the practical application scenarios we adapt to have complex and variability, so require the system must have good scalability and maintenance. To meet the changing requirements of functionality and performance. In the design technology of the system, we use components techniques such as OPC, COM / DCOM and 3D graphic controls. Component technology has good scalability and maintainability, reducing the complexity of the system. . And it also makes it easier for us to obtain third-party support, for example, please experience the graphics processing controls to write a graphics processing control, you can speed up the progress of the software development.
5. Software project implementation and management in this project
The demand for configuration software is more mature in the current industrial control field. Basically meet the functional requirements of the general user, by comparing a number of configuration software, it can be found that 80% of the functions between them are the same or Lei, due to the late start development, in the field of self-control, we are in a disadvantage, so we propose the idea of "heavy technical analysis, light demand analysis", that is, focus on the implementation of component design and architecture. .
In the equipment of the personnel, according to the technical composition of the configuration software, organize a group of CC masters that have a self-controlled, network, component, real-time system design, and hardware, have a descent and efficient team.
The principle of "quality first, progress second" is repeatedly emphasized on the development schedule.
In our project implementation, reliability as the primary principle of design, requires members of the project group to develop good programming habits, must complete the serious work logs every day, write work summary every week, complete a program code, you should Advance from the inside out, only from the foundation, the quality of the configuration software can be guaranteed.
Through the success of this project, I deeply realized that it is necessary to make the configuration software to play its own role in real-time control and information system integration, and must pay attention to the following points: advanced architecture; support ODBC real-time database; Powerful network function; features increasingly powerful scripting languages, etc. I am looking forward to my hard work through this field, I will overcome more and more abundant IT results.
comments:
This article seized a class of key software in real-time control and information system integration, the development of configuration software projects, which made more organized discussions, and the idea is very clear.
Due to the "versatility" in a certain extent, it is not possible to combine specific application background; however, a disadvantage of this article is that the actual effect example of development and application is not given, and it has not been able to encounter difficulties in development. Problem departure discussion. (This article mainly refers to the papers of Wang Qi floating in Guangdong)
