Name of pattern types 1 Process control patterns 2 Logic architectural patterns 3 Organizational patterns 4 Analytic patterns 5 Design patterns 6

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1 The Researches on Unified Pattern of Information System Deng Zhonghua,Guo Liang,Xia Yanping School of Information Management, Wuhan University Wuhan, Hubei, China Abstract: This paper discusses the unified pattern of the information system mainly. Patterning can reduce the uncertain factors in the project of information system and improve the success ratio of the system development effectively. Unified pattern attempts to set up a set of unified frames, makes the fields that correlated to the information system can all be patterned. Key words: Information system, Unified Pattern, Design patterns, Organizational patterns 1 Introduction One of the most difficulties in the project of information system development is the catching and confirmation of the requirements. This opinion is very popular. Based on this common understanding, people have carried on deep researches to the requirements and relevant propositions all the time. Not merely have summarized the methods of gaining the requirements (in technology aspect), managing change requirements (in management aspect), but even formed a whole set of requirement engineering. However, practices in recent years indicate, these have not brought obvious improvement to the state of the project of information system. Based on the census figures, success ratio is not high yet. Therefore, the obstacle of the information system development is not confining to some one or some several working contents, that is, all the processes of information system development are challenging. That is to say that each process and each level is the activity worthy being researched instead of an engineering project. Just because all activities in the information system development are creative (which proves there are many uncertain factors in the information system), which makes the information system development become to be high risk. According to practices for many years, an effective way to reduce the number of explorative items in project of information system development and advance engineering is the pattern (or patterning) and the result is remarkable. Design Patterns published by Erich Gamma etc in 1995 is a outstanding achievement which applied the pattern to the software development, later Martin Fowler published Analysis Patterns, applied the pattern to system analysis. These (mainly program designs) are helpful in system implementation and analyses. But information system is a system engineering, which makes majorities of developer are still at sea at the beginning of project (or at a new stage of project). The Unified Pattern this paper studies is to build a whole set of reference models, in the hope of making the developer " has regulations to abide by " no matter on any stage or any level of the project, enable the process being full of studying nature becomes a kind of " guide type ". 2 The Unified Pattern of information system Actually, the information system is still a kind of project with the quality of research at present. Except that the database technology has the standard processing mode, regular handling instruments and methods have not been formulated in the engineering of information system; the project developers have to probe and try every now of then. The goal of the researches on the unified pattern is to make the information system have more engineering nature (opposite to explorative nature). It gives many ready solutions that can be applied mechanically on any stage and any aspect to develop the system, thus dispel the uncertain factors, raising the success rate of the systematic development. The technology and management methods concerned in the development of information system are multidimensional and they have multi-level architecture, so whatever the organization or the description of patterns can't be treated in a single way. If we, however, design the handling methods of patterns in the light of concrete objects, the technical architecture will be complex and we will find it hard to operate. In this thought, in the practice of our researches to unified patterns we highlight the consolidation of operation, which includes the consolidation of operation method, the consolidation of

2 operation process, the consolidation of operation style. Under the support of unified pattern, systematic development is the activities of a series of pattern selections (certainly, we can create some new schemes according to conditions). Obviously, it has reduced the research in the project effectively. It is because there is pattern available, while setting about a new project (or entering the next stage in a project), you can choose a kind of pattern according to the characteristic. 3 the components and characteristics of the unified pattern 3.1 Types of Unified Patterns The information system is a complex framework, with multi-levels and multi-sides, composed of a series of logic models in terms of developing process, which are transformed into information system (solution domain) from the practical world (question domain). Still, a pattern of every level includes sub-level patterns. The pattern types are decided by such complex structural system. Several pattern types of them are listed in table 1. Table 1 Types of unified patterns Name of pattern types 1 Process control patterns 2 Logic architectural patterns 3 Organizational patterns 4 Analytic patterns 5 Design patterns Description of unified patterns As matters of substance in subject of information system, the method of description proposed in Design Patterns also can be applied expansively into other description of pattern. The method is to describe patterns by means of template. It however, didn t give sufficient explanation for those patterns of system level or patterns of process administrative nature. The example is, logic system architectural pattern of the system has two branches, centralized process patterns and distributed process patterns. The latter still includes C/S pattern, B/S pattern, N-tiers pattern and so on. There is a set of complete technical system in every single pattern. This is the reason why sufficient appendant illustration is necessary in description by means of template. The characters of the pattern need to be stressed in pattern description, such as the applicable occasion and the nature of the pattern. The properties, advantages as well as disadvantages should be elaborated explicitly in order to make it easier for the developers to use in the project. For the special characteristic on definite occasions, some typical indicator will be welcome. Those green hands of the field will benefit a lot of that from this, as well as to those who are somehow poor in background knowledge. They can understand the pattern in a short time and apply them correctly. In this way, the advantage of pattern method stands out. Choice principle is another field that needs to be considered. It helps examining the appropriate pattern from the view of requirements. In this sense, the description of choice principle stops at levels of pattern types, and it does not apply for the specific pattern. In anther word, choice principle targets at some certain pattern types, rather than the concrete pattern. 3.3 the Unified Pattern is Dynamic The unified pattern is a developing system, in accordance with the development of technology (mainly computer technology and software technology) and administration science. The unified patterns of information system has close relation with technology, for example, the Windows Pattern is selectable when designing information system under Windows operating system, which are MDI, SDI, and so on. While the menu pattern is the choice under DOS. With the emergence of the new technology, the unified

3 patterns will therefore undergo remarkable changes or be transformed into new mode. The unified patterns also bond with administration science. One typical example is Process Control Patterns. The project of information system can be taken following the sequence pattern; or following the prototype pattern (or spiral pattern) as well. This is the specific feature to organize and to implement information system projects, since other project can only take the pattern of sequence, such as construction project, water and electricity project etc. But the basic sequence pattern or basic spiral pattern does not suit for all the projects of information system. Accordingly, some adjustment is necessary. In addition, some new process control patterns have emerged through the combination of the two patterns in recent years. 4 Case analyses 4.1 the System of Unified Patterns The unified patterns system of information system is developing. The current system is a reflection of the perception level toward the information system. The unified patterns will undergo changes, with the development of technology and deepening apprehension of the human kind. From the visual angle of project, information system is a combination of administration and realization technology. To make it more practical, here we divide the unified patterns of information system into two levels, one is the type of the pattern (Pattern Type), the other the specific pattern. Unified Patterns Process control patterns Logic architectural patterns Organizational patterns sequence pattern spiral pattern RUP pattern Figure 1 the System of Unified Pattern The unified pattern of information system is composed of a few pattern categories (Pattern Types) including some particular patterns in each pattern category (such as the figure 1 show). The following is to list several instances of pattern categories to clarify briefly process control patterns The process control patterns (or process management patterns) means the management and the control patterns of the developing process of information system, it namely as the managing and implementing project pattern of the information system engineering process. Process control patterns contain two kinds of elementary patterns, they are respectively named that the sequence pattern based on waterfall model and the spiral pattern (or prototype pattern) based on spiral model. New patterns are coming out further taking the two elementary patterns as the foundation in the following sequence we list some representative patterns. 1.the sequence pattern It is the organizing and managing pattern to implementing system, which starts from the real world (the question domain) and layer by layer to transform according to the strict order; and finally achieve the aims. 2. the spiral pattern It is a pattern of organization and management. Comparing the sequence pattern, firstly it complete a part of each layer and not adopt the mean finishing all parts of a layer as the beginning of the next one,

4 then enlarge the contents gradually. 3. the RUP pattern The RUP pattern is a kind of process pattern set forth by the Rational. It combines sequence pattern and spiral pattern, according to the stage and process; carry out constitution and management to the system development. 4. the XP pattern It was set forth by Kent Beck in It divided the iterative increment smaller every time. Therefore it even has more adaptability of the variety. Moreover, the XP pattern quite emphasizes the program design Organizational pattern Organizational pattern means the way that systematic constitute. Two typical patterns of it are Structural Pattern and Object Pattern. The structural pattern organizes the system with the hierarchical structure and the module, while the object pattern use the concepts that object, type and packages to organize the system. On the level of program coding, the structural pattern is the Structural Programming and the object pattern is the Object-Oriented Programming Logic Architectural patterns What the logic architectural pattern describes is the distribution of the constitutive parts of the information system. The basic pattern is concentrated processing pattern and distributed processing pattern. C/S pattern is a representative pattern of concentrated processing pattern. C/S pattern has a few sub-patterns, such as the simple C/S pattern, N-tiers pattern, the B/S pattern, etc. 4.2 The instance of pattern description: sequence pattern Templates are used to describe patterns by Design Patterns, it also applicable to describe the logic architectural patterns and process control patterns. This section is to take sequence pattern that we are familiar with as an example, for the description of process control patterns The explanation of sequence pattern The sequence pattern is regarded as an earliest solution of process control. In the case, people were puzzled by the software crisis at that time and looking for a method to realize the software engineering. For avoiding losing control in the software produce, several major logic stages were measured off from project, and fulfilled stage by stage in sequence. It is visually named waterfall model as its diagram looks like the waterfall. The process of sequence pattern refers the whole life cycle to as a circulation. That is that a life cycle is the whole duration of information system, from the feasibility research, the organization implement, etc, to the maintenance and evaluation. Therefore, it is also titled the life cycle method on the engineering. With the waterfall pattern, the software developments with random activities are evolved in the way under control. So sequence pattern is the symbol that marking the software development enters the engineering period Template description of sequence pattern 1. The pattern and classification It is belong to the process control patterns 2. Intent For the sake of the assurance system development under the control, efficiently manage the degree of progress and quantities of the engineering, and evade the risk availably, the system development is needed to set off some stages, and each stage has clearly working contents and the engineering targets. Carry on the systematic programming and organize the implement according to the development stage of the order. 3. Also Known As Life cycle pattern, waterfall pattern 4. Motivation Organizing the systematic development according to orders changed from question domain to solution domain. The priority order of the systematic developing stage is stipulated strictly. This pattern was put forward based on the waterfall model.

5 5. Applicability The sequence pattern is the development course managing scheme put forward in the earliest stage; it offers the basis for development and management systematically. The sequence pattern is not only suitable for the small-scale software but also suitable for the development of the large-scale information system too. But because sequence pattern emphasizes every strict order of developing stage, that makes for the previous work becoming more important. So, while developing the system according to the sequence pattern, systems analysis is the most important stage in the whole project. The quality of system analysis will be the key to the systematic success or failure. Because the understanding of things by human is a gradual process, it is impossible to understand system clearly in system analysis stage; this is a main weakness in the sequence pattern. 6. Structure The basis of the sequence pattern is the waterfall model, the system exploitation made up of three mainly basic stages, but there can be other division schemes, for example, it could be raised to four stages or five stages, there can be more detailed steps in each stage. 7. Participants Three basic stages that develop systematically in the sequence pattern are: system analysis, system design, and system implement. Some schemes decompose feasibility research and demand analysis from system analysis, and some separate system maintain and appraise from system implement. So there will be four stages or five stages schemes, etc. Say summarily: Systems analysis is such an analysis which aims at requirements and functions of the information system based on the business (operation) analysis, and in order to draw the logic model of the system (analysis model); The system design is designing the system based on the system analysis. This stage solves the problem that how to realize the system and involves all technologies that the system uses, for instance, systematic structure, composition, database, interface, coding, etc.; The system implement mainly refers to how to realize the conversion from one system to another by writing procedure, including systematic maintenance and appraisal. 8. Collaborations The cooperation in the course control pattern mainly refers to the coordination relation for every stage. The sequence pattern requires that organizes systematic implementation according to the orders of every stage strictly, every stage is the foundation of working in the next stage. So, the next stage will never be launched before last stage was immature. Every work of stage should be evaluated, examined and approved, if it does not reach the requirement by evaluating, it should carry on the work at this stage again, if necessary, even return to the work in former stage. 9. Consequences The sequence pattern is one of the bases of the system engineering organization, it enriches planning and implementation of the information system with project nature. According to the technology that the system adopts, there are more adjustments in the project amount of every stage, for example, object-oriented technology makes analysis models carry out the transition to the design model smoothly, the efficiency about structural design improves obviously in the systematic design, while arranging the plan, the project amount in system design could be reduced properly. 10. Implementation Ignored. 11. Related patterns It was basic spiral pattern that corresponded to basic sequence pattern. Spiral pattern can be embedded in the sequence pattern (It is a little more proper to be called as the prototype pattern under the occasion). For example, adopt the prototype pattern to help to obtain the systematic prototype at the system analysis stage. It can also produce the new process control pattern by combining the basic sequence pattern with basic spiral pattern; for example, RUP pattern is a representative one among them.

6 5 Conclusion What the unified pattern of information system study is the method of patterning about the information system. As analyzed above, the unified pattern of information system can reduce the uncertain factors in the project effectively (namely reducing the research character of the project), raise project nature, and then in turn, raise the success rate of the systematic development. The unified pattern of information system has changed the way of the work to some extent, make the activity needing to be creative have more reference models. But the unified pattern of the information system does not limit creativity, because it just supports designing, make the work more easily, but not replace designing. What need to be pointed out is that the unified pattern of information system is about information system engineering, but not only limited in technology. It is the engineering system that the technology combines with management, for instance, the process control pattern among them. In addition, the unified pattern of the information system is an open frame system; it will be developing with the progress of technology and management. Reference [1] Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides. Design Patterns: Elements of Reusable Object-Oriented Software. Addison Wesley Longman, Inc [2] Deng Zhonghua. Analysis and Design for Information System. Science Press. Beijin China, 2003 [3] Kent Beck. Embracing Change with Extreme Programming. IEEE Computer, 1999 [4] Martin Fowler. Analysis Patterns: Reusable Object Models.