03 "Demand model-software modeling and Analysis"

Demand analysis is a requirement engineering activity which is used to solve the need of obtaining information and developing the software system solution which needs to be established. Demand analysis occupies an important position in demand engineering. In the process of demand analysis, we need to constantly collate, analyze, pay attention to every detail, determine the boundaries of the system. Set up a good model, if you encounter new problems, to timely collation of the records. Comprehensive application of demand analysis technology. Not only do you need to read extensively for each technology, but you need to do a lot of practice. There is no requirement analysis technology that can complete the task of modeling complex problems alone, and it is only through the organic combination and integration of various requirements analysis techniques that the complex applications can be fully described. The specific introduction of demand analysis technology in the book has highlighted the importance of demand analysis, but also let us learn the specific application of demand analysis technology, in the future software development needs, can no longer assume that how how. Demand analysis is both a complex and important process, each of which should be taken seriously, but also to learn the right remedy, so as to make the process more simple, easy to understand and easy to computerization.

"Requirements Engineering-software modeling and analysis" in the requirements of the documentation and verification of the main two parts, respectively, is the requirements specification and requirements validation, in the requirements Specification document is described in the requirements Specification document is a core element of the requirements specification activity, to understand the requirements specification activities, It is necessary to clarify the reasons for the documentation, the type of requirement Specification document, the reader of the requirement Specification document, the descriptive means of the requirement specification document, etc. The reason we write requirements specification documents on the one hand, a clear, clear, structured document can better deliver software requirements information and solutions to all developers. Documents can be consistently repeated to the requirements of the information to the developer, the effect is better, can be more accurate to the developer of information. On the other hand, documents can expand people's knowledge and memory ability. In a complex system, the content of information is not fully mastered by any one person. Written documents can not only be able to remember the ability of the forest people, but also effective records. Many different types of hydrangea specification documents can be produced in the process of requirement development. In the information description language can be divided into non-formal language, semi-formal language, formal language. In the writing requirements Specification, template selection and use is equally important, writing templates to choose carefully, to use the standard template, the developer of the project according to their own development of the standard template for building materials adjustment and customization, organize their own software Requirements Specification template. Requirements Specification document writing should pay attention to the contents of the organization, expression and details of the description. A good demand specification document features to be correct, unambiguous, completeness, consistency, importance-and stability classification, can be verified, modifiable, can be tracked. The specification writing of the requirement document can make the software less detours in the future, can develop the customer's demand according to the document, can make the software development more smoothly. In the requirement analysis, the document writing is an important step, its importance is that the quality of the document can directly affect the development of the project speed and the development of software. So in the document writing, we must standardize the writing, the specification of the requirements of the document can reflect the quality of a developer, good development habits.

Documentation and validation of requirements

Requirements specification. The requirements specification activity is the definition and documentation of requirements and software solutions, and is passed on to the developer's requirements engineering activities. Excellent requirements Specification documentation features: Correctness, ambiguity, completeness, consistency, classification based on importance and stability, verifiable, modifiable, and traceable.

The distinction and detailed definition of the validation and identification of the system and the verification and validation of the requirements:

① Requirements validation is the right form of assurance of demand.

② demand Confirmation. Confirm that each requirement is in accordance with the user's original intention. That is, its purpose is to ensure that the content of the requirements is correct.

③ system Validation. Establish the system correctly to ensure that the system performs the set function correctly in the expected environment.

④ System Confirmation. The established system is correct. Ensure that the system is built to meet system requirements and system design.

The process management of demand engineering: the environmental factors that need to depend on the engineering process are market characteristics, domain characteristics, technical maturity, organizational culture, project characteristics and so on. The establishment of the requirements engineering process includes the establishment of a process framework and the selection of work components in two steps. The requirements engineering process requires specific evaluation criteria and improvement methods. The evaluation can refer to the 66 practices of REGPG. The improved implementation steps include six steps to evaluate the current process, plan for improvement activities, train participants, implement new processes, measure new processes, and identify next actions. Process improvement needs to pay attention to the following matters: The requirements Engineering process in the context of the software process to implement the improvement, the implementation of the improvement should be based on the evaluation of existing processes, process improvement to target, process improvement should be planned, process improvement should be gradual and continuous.

03 "Demand model-software modeling and Analysis"