The sequence-based specification process is not allowed, and it is strictly forbidden to reprint this column. This paper is reproduced from the Software Engineering expert network www.21cmm.com. Do not reprint without CBS license, thank you for the development of cooperation. Order-based specifications refer to the process of gradually constructing complete, consistent and correct black boxes and status box specifications. This approach is this method. During the sequence-based specification, all possible incentives (historical excitation) sequences are systematically, such as 0, 1, 2 ... arranged in length. Because each sequence is mapped to its correct response, the equivalent sequence can be identified by applying the resort rule, and the system will end after the system is complete and consistently defined. Based on MILLS (1975), Pamas (1992), MAO (1993) DROWELL (1996) and Poore (ProWell and Poore, 1998), the sequence-based specification has a significant problem, and the combination of various situations of software use The number of use is an astronomical figure. Through sequence enumeration, developers consider all arrangements and combinations of system excitation. Each sequence represents a use scenario. During step-by-step, you have to distinguish possible scenarios and impossible scenarios, planned and erroneous uses, which can protected sequences and unsuitable sequences. These indiscriminate sequences (called typical sequences) are the foundation of the precise specifications of software behavior, which is complete, consistency, and trackable correctness in index skills. Sequence written enumeration provides complete direct verification. It is possible to verify all combinations and arrangements that have been mapped to a response from a small to large length (1, 2, 3, ...) one by one. Sequence sequence enumeration guarantees that any place to use only once. Like completeness, consistency is also a direct inference of enumeration. Each element based on the sequence can be traced back to the initial demand. If the correct response of a sequence cannot be found in the demand, you must clarify the desired behavior and modify the demand. The sequence-based specification workflow provides automatic support for the mastery of demand, black box specification, and status box specification in a continuous manner. The steps are made in the following subsections. Black box defines the needs of labels. Plus the demand plus the label serial number to verify the correctness of each element of the subsequent working product. The enumeration process can expose the need for ambiguous or missing place. It is natural to get a clear demand in a sequence-based specification. Define the system boundary. The system boundary determines that the component is internally or external to the system. The entity outside the system is the destination of an incentive source and response. The identification of the excitation and responses begins with the most basic level. Further consideration (may include the initial enumeration), it is often used to simplify the enumeration process. Abstract is used to hide detailed details. Natural division of the problem or a larger element set is set to a smaller element set. There must be a good definition to map the elements in the big collection to the elements in the small collection. The incentive set (or response set) may be mixed by different particle size (with basic, abstract). No matter what granular level, the incentive set (or response) must be mutually exclusive. Order enumeration. The arrangement of all sequences is listed in length. When examining each sequence, complete the following evaluation work: 1. It is impossible sequence (such as incentive before the system starts) labeled "illegal". Any illegal sequence extension is still illegal, so the sequence marked "illegal" is no longer expanded when listed. 2. The archive is recorded corresponding to the correct response of each sequence. If there is no need to correspond to it, you have to record an export requirement. Export requirements represent assumptions or explains, so you must confirm with the original needs. 3. If two sequences are the same for future incentives, they are called equivalents. Since the extension of the two equivalence sequences corresponds to the same behavior, there is no need to expand, just expand short. When all sequences or illegal or illegal or illegal or previous sequences are equivalent, the enumeration is stopped.
