Information technology for building systems
Practical use of information technologies is closely connected with the issues of marketing and management of information resources, technologies and services, the methodology of information systems design, quality management and the standardization of information technologies. At the present time, the ideology and practice of using information technologies has been formed on the whole. However, it is necessary to organize information processes and technologies, as a system, for the construction of which it is expedient to apply a systematic approach.
The most full-system approach was manifested in the design of information systems. The methodology of designing information systems as a collective process is proposed. The main stages and tasks of introduction and maintenance of information technologies on the basis of object-oriented technology, as the basis for creation of open, flexible, multifunctional systems for various subject areas are analyzed. Considerable attention is paid to the formation of the domain model using various means for automation of the design process, analysis of design quality.
A systematic approach to building information systems
The classical design of IP originates in the 70s of the last century. One of the first directions was named "cascade" design schemes. It was widely used in the design of the automated control system and included the following stages of the project: launching, survey, technical task concept, draft design, technical design, working draft, commissioning (implementation). The main feature of this technique is the consistent organization of work when the IS structure is divided into a predetermined number of subsystems: organizational, methodical, informational, software and hardware. In Western literature, this scheme of work organization was called the "waterfall model" (waterfall model) and included additional iterative procedures to refine the requirements for the system and consider design options. The main drawbacks of the cascading design schemes are delay in obtaining final results and low efficiency.
In the process of improvement, a scheme for the continuous development of IP (Figure 7.1), which was used to implement large projects of IBM in 1970-1980, appeared. A characteristic feature of this technique was a continuous spiral process of developing IS with planned points of transfer into operation of new versions and new functional subsystems.
The development of a continuous development scheme is associated with the improvement of cyclic design forms. An example of this approach is the accelerated design method, called "Fast Prototyping". In the project cycle, the stages of prototype development and prototype testing were additionally included. The drawbacks of the continuous development scheme are the rigidity of the design models used and the closedness of the generated IS.
The consequence of the shortcomings of the classical design methods was the transition to system design.
The system approach operates a number of categorical concepts. Its fundamental concept is the concept of a system, giving which it is necessary to pursue a specific goal. If the goal is the cognition of an already existing system, then descriptive definition of the system is quite suitable, which consists in the following: a system is a collection of objects whose properties are determined by the relationship between these objects . Objects are called subsystems or elements of the system. Each object can be considered as a system in case of independent research. The functions of the object are determined by its internal device. Thus, the descriptive definition of the system plays a cognitive role for explanation
Fig. 7.1. Continuous development plan
functions implemented by it. Functions of the system are manifested in the process of its interaction with the external environment. It is important to determine the boundary between the external environment and the system being created. This can be done on the basis of a constructive definition of the system. Of particular importance is the constructive approach for technical systems.
Any technical system is created with a pre-known purpose. The purpose of such a system is usually subjective, as it is proposed by the developer, but this goal must be based on the objective needs of society. Thus, we can assume that the goal is formed in the process of interaction between the phenomena of reality surrounding us. In this case, a situation arises that forces us to build a new system. The situation can become problematic if it is not resolved by available means. New missing means can be created, and in this sense, a clear example is information technology.
The society has long formed the ideology and practice of using various means of collecting, transmitting, storing, processing and presenting information. However, their disparate application or use of their limited aggregate has not yet allowed a significant systemic effect. An approach to information technology as a system is needed. Such an approach is justified in view of the fact that information technology has a single goal, namely, the need to create an information resource in a society, has associated interacting means of its implementation, is characterized by a development trend due to the intensive updating of computer facilities and communication technology. Analysis of information technology as a system should be carried out on the basis of a descriptive definition, the development of information technology should be based on a constructive approach. This approach requires the emergence of a problematic situation for the development of the system. We can assume that the arising problem generates the future system. First of all, the developer must determine the boundaries of the system, believing that the purpose of its functioning is known. It is necessary to include in the structure of the system those elements that, by their functioning, ensure the realization of a given goal, and consequently, a constructive definition of the system is as follows: a system is a finite set of functional elements and relations between them that are distinguished from the environment in accordance with the goal in the framework a certain time interval for its realization . All that is not included in the system is referred to the environment. Obviously, the environment includes other systems that realize their goals of functioning. The inputs and outputs of the system are connected to the external environment. At the model level, the model of the system, the model of the external environment at the input of the system, the model of the external environment at the output of the system and the model of connections between the system and the external environment at the input and output are singled out. The external environment for information technology can be production, scientific research, design, training, etc. The links between information technology and the external environment are purely informative. In the process of interaction with the external environment, the basic functions of information technology are realized. Functions as a manifestation of the properties of a system in time are closely related to its structure. The descriptive approach is realized by studying the function or structure of the system. In accordance with this, functional and structural approaches have been applied in system theory.
Given that the structure reflects the links between the elements of the system, taking into account their interaction in space and time, it can be argued that the structural approach is the development of a descriptive approach. It serves to study (cognize) some existing system. The functional approach reflects the functions of the system, implemented in accordance with the goal set before it. Therefore, the functional approach is the development of the constructive. The functions of the system must be specified when constructing it and should be implemented when the system functions.
The structure of the system is described on the conceptual, logical and physical levels. The conceptual level allows to qualitatively define the main subsystems, elements and connections between them. At the logical level, models describing the structure of individual subsystems and interactions between them can be formed. The physical layer means the implementation of the structure on known hardware and software. Since the technical system is created artificially, the purpose of its functioning is preliminarily subjectively known. We can assume that this goal corresponds to a certain list of functions and some optimal structure of the system. This structure was called formal. It is understood as a set of functional elements and the relationships between them, necessary and sufficient to achieve the system a given goal. A formal structure is some ideal structure that does not have physical filling. This structure is realized by various means, therefore it can correspond to a number of real fillings. The external environment, interacting with information technology as a system, can act as a metasystem, setting before it certain tasks and formulating goals. The introduction of information technologies in the life of society over a finite time interval will have an effect if the systems into which information technologies are introduced are typified and the typical structures of the latter are identified. Depending on the system in which information technology is introduced, a different spatial distribution of users and information technology tools is possible. A set of tasks can be different. The nature and timing of the implementation of the objectives of information technology also depend on where it is used: in industry, research, design, training, etc. It is very important to coordinate the structure of information technology with the organizational structure of the system in which it is used. The absence of typical organizational management structures of the enterprise, production processes significantly complicates the possibilities of using information technologies. The task is to create a wide range of specific information technologies that are tuned to the parameters of real systems. Thus, for the system engineer, information technology becomes a mass development object.
When using information technology in a systemic aspect, the following principles should be observed:
1. Presence of the formulated common goal for information technologies within the framework of the system being developed.
For global information technology, such an aim is the formation of an information resource in society. For basic information technology, the goal can be the accumulation of information and the formation of knowledge to create a conceptual model for the production of the final product. For each type of information technology, one must formulate its own local goals, subject to their common goal, a certain metasystem.
2. Harmonization of information technologies on inputs and outputs with the environment.
In information technology as a system, optimal access points for users should be determined, provided they are highly intellectualized, which will facilitate the wide introduction of information technologies in all spheres of human activity. The structure of information technology should fit organically into the organizational structure of the system where it is applied. It is necessary to carry out the optimal distribution of information technology tools with their adaptation to the capabilities of users at all levels of production management, scientific research, design.
3. Typification of information technology structures.
This primarily applies to basic information technology. A typification of the systems into which information technologies are introduced and the typification of the structures of the basic technologies by the areas of their application should be carried out. There are obvious specific features of the structural implementation of technology in production, scientific research, integrated testing, design, training. Particular attention should be paid to specific information technologies with heme, so that they can be adjusted to the real parameters of the system.
4. Standardization and mutual coordination of information technology tools.
The experience of implementing information technologies in various subject areas has shown that only with maximum typing of design solutions and standardization of their implementations is the success in the use of new technology possible.
5. Openness of information technologies as a system.
When developing information technology, the initial goal of its creation in some cases will be incomplete, so the information technology created should be capable of development both vertically and horizontally and cover all levels of management and automation of production. In the process of functioning information technology due to the work of the designer should be supplemented with new solutions of problems. It is necessary to provide for the expansion of the domain model to which the information technologies are configured.