Sooner or later, modern organizational leaders come to the conclusion that it is necessary to automate various management functions of their business: as a rule, this is caused by the desire to reduce costs by optimizing the production process and optimizing the management of various business processes. In such a case, organizations either purchase ready-made standard information systems available on the IT services market, or attract specialists and develop information systems directly for a given enterprise, taking into account its specifics and field of activity. The first option is more economical, the second is more promising, since specially developed IS take into account the structure of the organization and should be better suited for automating the function of a particular organization.
The basic concept of information systems development methodology is the concept IS life cycle. The life cycle of a system is usually understood as a continuous process that begins from the moment a decision is made about the need to create a system and ends when it is completely removed from service. In other words, IS life cycle is period of creation and use of IP.
The life cycle of an information system covers all stages and phases of its creation, maintenance and development:
· pre-project analysis (including the formation of functional and information models of the object for which the information system is intended);
· system design (including development of technical specifications, preliminary and technical designs);
· system development (including programming and testing of application programs based on design specifications of subsystems identified at the design stage);
· integration and assembly of the system, testing it;
· operation of the system and its maintenance;
· development of the system.
At the stage of pre-design analysis, the subject area for which the system is being developed is studied. Customer requirements for the future system are formed, future functions and parameters of the system are outlined. An approximate estimate of future material and time costs is made.
At the design stage, a system project is developed in the form of diagrams, drawings and calculations, the image of the future system is described, and design solutions are given for all its components. The purpose of the design is the selection of technical and formation of information, mathematical, software and organizational and legal support.
The effective functioning of an IS is primarily determined by the quality of design; it is during design that a detailed image of the system is created, capable of further functioning with its constant improvement. As a result of the design, a set of technical documentation is formed, which serves as the basis for building an IS.
IC design is based on a number of principles:
Principle systematic or a systems approach. The principle of systematicity presupposes consideration of an object as a single whole; identifying connections between structural elements that ensure the integrity of the system; establishing the direction of the production and economic activities of the system and the functions it implements.
Principle development economic information systems (EIS) - provides that when creating an IS, it should be possible to quickly and without large costs for restructuring changes and build-up of IT when changing and developing an object.
- Compatibility- assumes the possibility of interaction between EIS of different levels and types in the process of their joint functioning.
- Standardization and unification- involves the use of standard, unified and standard solutions in the creation and development of electronic information systems (standard software products, unified documentation, equipment).
- Principle of efficiency– a rational relationship between the costs of creation and operation and the effect of the functioning of the created system.
- Integration– this is the integration into a single technological process of procedures for collecting, transmitting, accumulating, storing information and procedures for forming management decisions.
The actual creation of the system occurs at the development stage.
The need for the development stage is due to the fact that over the period of use of the system (about 10 years), the hardware and software become morally and physically obsolete, and therefore it is necessary to periodically modernize the software and hardware base of the IS.
At each stage of the life cycle, a certain set of documents and technical solutions is formed, and for each stage the initial documents and decisions obtained at the previous stage are used.
The progress of the IS creation process (the order of execution of stages, the criteria for moving from stage to stage) depends on the chosen IS life cycle model. Life cycle model- a structure that determines the sequence of execution and relationships between processes, actions and tasks performed throughout the life cycle.
To date, the following two main life cycle models have become most widespread:
· cascade model (70-85);
· spiral model (86-90).
Cascade method- dividing the entire development into stages, and the transition from one stage to the next occurs only after the work on the current one is completely completed (Fig. 1.2.1). You can see the IS development diagram according to the cascade approach in the text file accompanying this lecture.
Positive aspects of using the cascade approach:
· at each stage, a complete set of design documentation is generated that meets the criteria of completeness and consistency;
· stages of work carried out in a logical sequence allow us to plan the completion time of all work and the corresponding costs.
The cascade approach has proven itself well in the construction of information systems, for which all requirements can be quite accurately and completely formulated at the very beginning of development. Complex computational systems, real-time systems, and other similar tasks fall into this category.
The main disadvantage of the cascade approach is the significant delay in obtaining results, since it is often necessary to return to previous stages due to changes that have arisen (for example, due to changed customer requirements).
Spiral model, in contrast to cascade, involves an iterative process of developing an information system. Each iteration represents a complete development cycle, resulting in the release of an internal or external version of a product (or a subset of the final product) that is improved from iteration to iteration to become a complete system. The principle of development using the spiral model becomes clear if you look at the presented figure.
Each turn of the spiral corresponds to the creation of a new fragment or version of the IP; the goals and characteristics of the project are clarified, its quality is determined, and the work of the next turn of the spiral is planned. In this case, one turn of the spiral represents a complete project cycle similar to a cascade scheme. Using the spiral model allows you to move to the next stage of the project without waiting for the current one to be completely completed - unfinished work can be completed at the next iteration.
The spiral model is more common these days. The reasons for this are a lower level of risks compared to the waterfall model, reduced development time, and ease of making changes. In general, the spiral model turns out to be more flexible compared to the cascade model.
The main problem of the spiral cycle is determining the moment of transition to the next stage. The transition proceeds as planned, even if not all planned work is completed.
The increasing complexity of modern automated control systems and increasing requirements for them dictate the need to use effective technologies for creating and maintaining information systems throughout the entire life cycle. Such technologies, focused on supporting the full life cycle of the NPP or its main stages, are called CASE technologies (Computer Aided System Engineering). CASE technology is an IS design methodology, as well as a set of tools that allow you to visually model a subject area, analyze this model at all stages of IS development and maintenance, and develop applications in accordance with the information needs of users. In the last decade, a class of software and technological tools (CASE tools) has emerged that implement the CASE technology for creating and maintaining AIS. Currently, CASE tools (>300) cover the entire process of developing complex AIS as a whole. Now the term CASE tools refers to software tools that support the processes of creating and maintaining AIS, including analysis and formulation of requirements, design of application software and databases, program code generation, testing, documentation, quality assurance, configuration management and project management, as well as other processes .
CASE tools:
Improve the quality of created AIS (AIT) through automatic control means;
They allow you to create a prototype of a future automated information system (AIT) in a short time, which makes it possible to evaluate the expected result at an early stage;
Speed up the process of system design and development;
They free the developer from routine work, allowing him to concentrate entirely on the creative part of development;
Support the development and support of the development of AIS (AIT);
Support technologies for reusing development components.
Modern CASE tools cover a wide range of support for numerous IS design technologies: from simple analysis and documentation tools to full-scale automation tools covering the entire software life cycle.
Typically, CASE tools include any software that automates one or more processes in the software life cycle and has the following main characteristic features:
· powerful graphical tools for describing and documenting IP, providing a convenient interface with the developer and developing his creative capabilities;
· integration of individual components of CASE tools, ensuring controllability of the IS development process;
· use of a specially organized storage of project metadata (repository).
The following types of CASE funds are distinguished:
Local tools that solve small autonomous tasks (tools),
A set of partially integrated tools covering most stages of the IS life cycle (toolkit)
Fully integrated tools (CASE-tool complexes) supporting the entire life cycle of the IS and connected by a common repository.
An integrated CASE tool (or a set of tools that support a complete software life cycle) contains the following components;
· repository, which is the basis of the CASE tool. It should ensure storage of versions of the project and its individual components, synchronization of information received from various developers during group development, control of metadata for completeness and consistency;
· graphical analysis and design tools that provide the creation and editing of hierarchically related diagrams (DFD, ERD, etc.) that form IS models;
· application development tools, including 4GL languages and code generators;
· configuration management tools;
· documentation tools;
· testing tools;
· project management tools;
· reengineering tools.
b) by type:
Analysis tools (Upper CASE) designed for building and analyzing domain models
Analysis and design tools (Middle CASE) that support the most common design methodologies and are used to create design specifications. The output of such tools are specifications of system components and interfaces, system architecture, algorithms and data structures;
Database design tools that provide data modeling and generation of database schemas (usually in SQL language) for the most common DBMS.
Application development tools.
Reengineering tools that provide analysis of program codes and database schemas and the formation of various models and design specifications based on them.
Today, the Russian software market has the following most developed CASE tools:
· CASE.Analyst;
· Rational Rose.
One of the important characteristics of IS development is the development time. Often, the time required to create a full-fledged system takes from several months to a year. It is quite natural that most enterprises are interested in reducing this period. One of the possible solutions to this problem is the development of IS using the RAD (Rapid Application Development) methodology. = Rapid Application Development Methodology.
The basic principles of the RAD methodology can be summarized as follows:
Using an iterative (spiral) development model;
Complete completion of work at each stage of the life cycle is not necessary;
In the process of developing an information system, close interaction with the customer and future users is ensured;
CASE tools and rapid application development tools are used;
Configuration management tools are used to facilitate making changes to the project and maintaining the finished system;
Prototypes are used to better understand and realize the needs of the end user;
Testing and development of the project are carried out simultaneously with development;
Development is carried out by a small and well-managed team of professionals;
Competent management of the system development, clear planning and control of work execution are provided.
When using the rapid application development methodology, the life cycle of an information system consists of four phases:
Requirements analysis and planning;
Design;
Constructions;
Implementations.
The RAD methodology is also not suitable for creating complex calculation programs, operating systems and programs for managing complex engineering and technical objects, that is, programs that require writing a large amount of unique code.
Completely unacceptable methodology RAD for the development of systems on which human safety depends, such as control systems for transport or nuclear power plants.
There are two main design methods: structural and object-oriented design.
The essence of the structural approach to IS development lies in its decomposition (breakdown) into automated functions: the system is divided into functional subsystems, which in turn are divided into subfunctions, subdivided into tasks, and so on. The partitioning process continues down to specific procedures. At the same time, the automated system maintains a holistic view in which all components are interconnected. When developing a system "bottom-up" from individual tasks to the entire system, integrity is lost, and problems arise in the information connection of individual components.
Object-oriented design involves an object-based decomposition of the system. An object is a real-life entity that has an important functional purpose in a given subject area. An object is characterized by structure, state, and clearly defined behavior. The state of an object is defined by a list of all possible (usually static) properties and the current values (usually dynamic) of each of these properties. The properties of an object are characterized by the values of its parameters.
So today we looked at some aspects of the IP development process. In particular, we defined what an IS life cycle is and described its main stages, and characterized the 2 main models of an IS life cycle – cascade and spiral. Then we identified an important tool in the development and maintenance of IS - CASE tools that help analyze, design, develop and effectively use IS, i.e. support the entire life cycle of the IS.
The design of information systems (IS) is a complex multi-stage activity, without the scientific organization of which the creation and use of modern complex IS is unthinkable, including in education, entrepreneurship, management and other areas of society. Along with obtaining the necessary theoretical knowledge for this, the IS designer needs to acquire stable practical skills in this type of activity.
The main feature of design is working with an object that does not yet exist. This is the difference between design and modeling, where an object cannot but exist.
IC design covers three main areas:
Design of data objects that will be implemented in the database;
Designing programs, screen forms, reports that will ensure the execution of data queries;
Taking into account the specific environment or technology, namely: network topology, hardware configuration, architecture used (file-server or client-server), parallel processing, distributed data processing, etc.
Information systems design always begins with defining the purpose of the project. In general terms, the goal of the project can be defined as solving a number of interrelated tasks, including ensuring at the time of system launch and throughout the entire period of its operation:
The required functionality of the system and the level of its adaptability to changing operating conditions;
Required system throughput;
Required system response time to a request;
Failure-free operation of the system;
Required level of security;
Ease of operation and system support.
Design technology
AIS design technology is a set of methods and means for AIS design, as well as methods and means for organizing design (managing the process of creating and modernizing an AIS project). The design technology is based on the technological process (TP), which determines the actions, their sequence, the composition of performers, the means and resources required to perform these actions.
TP of AIS design is a set of sequential-parallel, connected and subordinate chains of actions, each of which can have its own subject. The actions that are performed when designing an AIS can be defined as indivisible technological operations or as subprocesses of technological operations.
All actions can be actually designed, which form or modify design results, and evaluative, which are developed according to established criteria for assessing design results.
Thus, the design technology is determined by a regulated sequence of technological operations performed in the process of creating a project based on one or another method.
The subject of the selected design technology should be a reflection of interrelated design processes at all stages of the AIS life cycle.
The main requirements for the selected design technology are as follows:
The project created using this technology must meet the customer’s requirements;
The technology should reflect as much as possible all stages of the project life cycle;
The technology must ensure minimal labor and cost costs for design and project support;
Technology should help increase the productivity of designers;
The technology must ensure the reliability of the design and operation of the project;
Technology should facilitate easy maintenance of project documentation.
AIS design technology implements a specific design methodology. In turn, the design methodology presupposes the presence of a certain concept, design principles and is implemented by a set of methods and tools.
AIS design methods can be classified according to the degree of use of automation tools, standard design solutions, and adaptability to expected changes.
According to the degree of automation there are:
Manual design;
Computer aided design;
Based on the degree of use of standard design solutions, they are distinguished:
Original design;
Standard design;
The following methods differ in the degree of adaptability of design solutions:
Reconstruction - adaptation of design solutions is carried out by processing the relevant components;
Parameterization – design solutions are configured in accordance with specified and changeable parameters;
Model restructuring – the model of the subject area is changed, which leads to automatic reformation of design solutions.
Depending on the complexity of the automation object and the set of tasks that need to be solved when creating a specific AIS, the stages and phases of work may have different labor intensity. It is possible to combine successive stages and exclude some of them at any stage of the project. It is also allowed to begin the work of the next stage before the completion of the previous one.
The main stages of creating an automated information system:
Formation of requirements for AIS;
Development of the AIS concept;
Development of technical specifications;
Development of a project sketch;
Development of the technical part of the project;
Development of working documentation for AIS;
Commissioning;
AIS support.
Design methodology
The basis of information systems design technology is methodology. The methodology is implemented through specific technologies and supporting standards, methods and tools.
IS design methods can be classified according to the degree of use of automation tools, standard design solutions, and adaptability to expected changes. Thus, according to the degree of automation, design methods are divided into:
1. Manual, in which the design of IS components is carried out without the use of special software tools, and programming is done in algorithmic languages;
2. Computer-based, in which design solutions are generated or configured (setup) based on the use of special software tools.
Based on the degree of use of standard design solutions, the following design methods are distinguished:
1. Original (individual), when design solutions are developed “from scratch” in accordance with the requirements for AIS. It is characterized by the fact that all types of design work are focused on creating individual projects for each object, which reflect all its features to the maximum extent;
2. Standard, which involves configuring an IS from ready-made standard design solutions (software modules). Performed on the basis of experience gained in the development of individual projects. Typical projects, as a generalization of experience for certain groups of organizational and economic systems or types of work, in each specific case are associated with many specific features and differ in the degree of coverage of management functions, work performed and project documentation developed.
Based on the degree of adaptability of design solutions, the following methods are distinguished:
1. Reconstruction, when adaptation of design solutions is carried out by processing the relevant components (reprogramming software modules);
2. Parameterization, when design solutions are configured (generated) in accordance with the changed parameters;
3. Model restructuring, when the model of the problem area changes, on the basis of which design solutions are automatically regenerated.
The combination of various characteristics of the classification of methods determines the nature of the IC design technologies used, among which two main classes are distinguished: canonical and industrial technologies. Industrial design technology, in turn, is divided into two subclasses: automated (using CASE technologies) and standard (parameter-oriented or model-oriented) design. The use of industrial technologies does not exclude the use of canonical ones in some cases.
Design is a practical activity, the purpose of which is to find new solutions, presented in the form of a set of documentation. The search process is a sequence of interdependent actions and procedures, which, in turn, involve the use of certain methods. The complexity of the design process (like any other creative activity), the non-standard nature of design (life) situations necessitate knowledge of various methods and the ability to master them.
Design technology is defined as a combination of three components:
A step-by-step procedure that determines the sequence of technological design operations;
Criteria and rules used to evaluate the results of technological operations;
Notations (graphical and textual means) used to describe the system being designed.
Comparative characteristics of design tools
The main purpose of choosing a corporate standard for organizational design is to specify a common and mandatory language of communication for management, developers of organizational and technological processes and executors of these processes. Particular applications of such standards are the synthesis of requirements for created systems, regulations on organizational units, service instructions, etc.
There are about 30 technologies for designing organizational and technical systems and several hundred tools designed to automate this process. Therefore, taking into account the time factor, the comparative analysis was limited to the four most popular products on the Russian market: Bpwin/Erwin (Platinum Technology), Rational Rose (Rational Software Corporation), ARIS (Scheer AG) and Oracle Designer (Oracle Developer Suite). Reference data on CASE technologies and design tools are given below in the text and in Table No. 1.
Table 1
Design tools and their comparative characteristics
|
Criteria |
Oracle Designer |
|||
|
Full IP life cycle support | ||||
|
Ensuring Project Integrity | ||||
|
Platform independent |
+ (DoDAF, TeaF/FeaT, Zachman) |
+ (ORACLE, Informix, Sybase) |
+ (ORACLE, Informix, Sybase, Ingres, etc.) | |
|
Simultaneous group development of databases and applications |
*) application developers can start working with the database only after its design has been completed.
CASE technology is an IS design methodology, as well as a set of tools that allow you to visually model a subject area, analyze this model at all stages of IS development and maintenance, and develop applications in accordance with the information needs of users. Most existing CASE tools are based on structural (mostly) or object-oriented analysis and design methodologies, using specifications in the form of diagrams or texts to describe external requirements, relationships between system models, system behavior dynamics, and software architecture.
According to a review of advanced technologies compiled by Systems Development Inc. in 2007, based on the results of a survey of more than 1,000 American companies, CASE technology is currently ranked among the most stable information technologies (half of all surveyed users used it in more than a third of their projects, of which 85% were completed successfully). However, despite all the potential capabilities of CASE tools, there are many examples of their unsuccessful implementation, as a result of which CASE tools become “shelfware”. In this regard, the following should be noted:
1. CASE tools do not necessarily have an immediate effect; it can only be received after some time;
2. The actual costs of implementing CASE tools usually far exceed the costs of purchasing them;
3. CASE tools provide opportunities to obtain significant benefits only after the successful completion of their implementation process.
Due to the varied nature of CASE tools, it would be erroneous to make any blanket statements regarding the actual satisfaction of particular expectations from their implementation. The following factors can be listed that make it difficult to determine the possible effect of using CASE tools:
1. Wide variety of quality and capabilities of CASE tools;
2. Relatively short time of using CASE tools in various organizations and lack of experience in their use;
3. Wide variety in the implementation practices of various organizations;
4. Lack of detailed metrics and data for already completed and ongoing projects;
5. Wide range of subject areas of projects;
6. Varying degrees of integration of CASE tools in different projects.
As a result of these complexities, the available information on actual implementations is extremely limited and inconsistent. It depends on the type of tools, project characteristics, level of support and user experience. Some analysts believe that the real benefits of using some types of CASE tools can only be realized after one or two years of experience. Others believe that the impact may actually occur during the operational phase of the IS life cycle, when technological improvements can lead to lower operating costs.
The SP category includes both relatively cheap systems for personal computers (PCs) with very limited capabilities, and expensive systems for heterogeneous computing platforms and operating environments. Thus, the modern software market includes about 30 different CASE systems, the most powerful of which, one way or another, are used by almost all leading Western companies.
The use of SP requires special preparation and training from potential users. Experience shows that the implementation of SP is slow, however, as practical skills and a general design culture are acquired, the effectiveness of using these tools increases sharply, and the greatest need for using SP is experienced at the initial stages of development, namely at the stages of analysis and specification of requirements. This is explained by the fact that the cost of errors made at the initial stages is several orders of magnitude higher than the cost of errors identified at later stages of development.
Today, the Russian software market has the following most developed joint ventures:
ERWin/BPWin;
Rational Rose;
Oracle Designer.
ARIS - An integrated business process modeling tool that combines a variety of systems modeling and analysis methods. First of all, it is a means of describing, analyzing, optimizing and documenting business processes than a software design tool.
BPWin is a tool for visual modeling of business processes. ERWin is a tool used for modeling and creating databases of arbitrary complexity based on entity-relationship diagrams.
Rational Rose is a tool for modeling object-oriented information systems. Allows you to solve almost any problem in the design of information systems: from business process analysis to code generation in a specific programming language. Allows you to develop both high-level and low-level models, thereby performing either abstract or logical design.
Oracle Designer is a functional tool for describing a subject area. Included in the Oracle9i Developer Suite set of tools for designing software systems and databases that implement CASE technology and Oracle’s own IS development methodology - “CDM”, allowing the development team to carry out a project, starting from business process analysis through modeling to code generation and obtaining prototype, and subsequently the final product. This tool makes sense when targeting the entire Oracle product line that is used to design, develop, and implement a complex software system.
Analysis of the data given in the table shows that of the listed joint ventures, only the ARIS complex most fully satisfies all the criteria accepted as the main ones. For example, in the Rational Rose complex, the integrity of the design database and a unified end-to-end IC design technology is ensured through the use of the Corba interface. It should be noted that each of the two products is itself one of the most powerful in its class.
Thus, the most developed means of developing large-scale IS today, according to the author, is the ARIS complex.
Nowadays, the information industry has become a new branch of technology, bringing great benefits to users. Therefore, in modern conditions, the head of an organization must have knowledge of the methodological foundations of creating an IP. Knowledge of the methodological principles of creating and using information systems is closely related to the development and improvement of management processes.
The founder of cybernetics (science of systems and control methods) is Norbert Wiener (USA). The works of his followers became the foundation of the theory of automatic control. This is the science of the general laws of receiving, storing, transmitting and converting information in complex control systems. The use of computer technology to solve control problems led to the development of information theory, coding theory, and the formation of an independent scientific field of computer science. The results of these studies formed the basis for the development of a methodology for the use of hardware and software to solve problems of various practical purposes.
Economic objects began to be viewed as complex systems, and their management was identified with the information process. The intensive development of the capabilities of computer technology and the scope of its application has led to the creation of human-machine information systems in economic objects. The purpose of the IS was not only information support of production and economic processes, solving functional management problems within the organization, but also information interaction between various interconnected organizations in production, economic and information aspects.
The founder of unified methodological approaches in IS design was Academician V.M. Glushkov, who formulated scientific and methodological provisions and practical recommendations for creating an automated information system. The main principles of unified methodological approaches are:
1. The principle of consistency, which is the most important in the creation, operation and development of IP. He considers the economic object under study as a single whole. At the same time, it establishes the directions of the organization’s production and economic activities and the specific functions implemented by it; detects various types of connections between its structural elements ensuring the integrity of the system. The principle of systematicity involves conducting two aspect analysis in the organization, namely macro- and microanalysis. In macroanalysis, the system and (or) its “elements are considered as part of a higher order system. Particular attention is paid to information connections: their directions of movement are established, those connections that are determined by the purpose of functioning and studying the object are identified and analyzed, and then the most preferable ones are selected, taking into account in the process of designing an IS. In macroanalysis, all aspects of the organization's activities are studied, its structural components are analyzed (including activities at each workplace) with a view to their functional characteristics, manifested through connections with other elements and the external environment.
When designing an IS for the organizational structure of managing an economic entity, a multi-level hierarchical structure is most typical. The hierarchical structure for each level of the system allows for various combinations of local optimality criteria with the global optimality criterion for the functioning of the system as a whole; provides relative flexibility of the control system and the ability to adapt to changing conditions; increases reliability due to the possibility of introducing elemental redundancy and streamlining the directions of information flows. The advantages of hierarchical structures contributed to their widespread use in management systems and determined the organizational and functional approach to the creation of information systems. The experience gained during this process influenced the modern process approach to IS design.
The practical significance of the application of the system principle is that it allows, in a form accessible for analysis, not only to identify the interests of the system creators, but also to use computer modeling to study the behavior of the designed system in specific conditions specified by the experimenter. Therefore, the creation of an IS is based on the modeling method, which allows one to find the most acceptable and justified design solutions, options for constructing a system, and thereby ensure the greatest efficiency in the functioning of an economic object.
2. The principle of development, which is that the IS is created taking into account the possibility of constantly replenishing and updating the functions of the system and the types of its support. Its essence is that developing production and management processes are becoming more complex and the organizational structures of economic objects are being rebuilt - this necessitates increasing the computing power of information systems, equipping them with new technical and software tools for constantly replenishing and updating the tasks being solved, expanding the information fund, created in the form databases and data warehouses, knowledge bases.
3. The information principle, which is aimed at a detailed and comprehensive study of information and information processes accompanying management processes in an economic entity. Information is studied in semantic (content), syntactic (sign) and pragmatic (useful) aspects. In addition, the study of information is necessary for the design of automated workstations, systems for transmitting, storing and processing data, and protecting information, where the main ones are knowledge of the volume, content and usefulness of information.
Currently, an object-oriented method for modeling information processes and automating design work for analyzing management processes and designing electronic information flows is based on the information approach.
4. The principle of compatibility, which consists in ensuring the interaction of information systems of various types, purposes, levels in the process of functioning of an economic object. Therefore, in the design process, systemic unity of methodological approaches in solving problems of information, technical, and software compatibility of all information systems used must be ensured. The unity of methodological approaches is reflected in regulatory documents regulating the process of development, documentation, acceptance and operation of information systems. These are international and domestic standards (GOST), industry and departmental regulatory materials, regulations, protocols, and organizational standards.
Standards regulating language means of information processing, communication technologies and computing organizations, object-to-object interaction, and the like are widely used.
5. The principle of standardization and unification, which consists in the need to use standard, unified and standardized elements of the functioning of the IS. This primarily applies to the components of information, technical, software and other IT support subsystems. This principle makes it possible to reduce time, labor and cost costs for creating an IS while making the maximum possible use of the accumulated experience in the formation of design solutions and the introduction of automation of design work, and ensures multi-aspect interaction of the IS.
6. The principle of decomposition, which is based on dividing the system into parts and separating individual sets of work, creates conditions for a more effective analysis of the existing state of management activities, studying the features of solving functional problems for further modeling of specific aspects of management activities and transferring them to automated technology. The principle is used both when studying the features of the properties of elements and the system as a whole, and when creating an IS on a new information technology base.
7. The principle of efficiency, which consists in achieving a rational ratio between the costs of creating an information system and the target effect obtained during its operation.
Description of the life cycle of an information system involves operating with the following concepts:
Process - a chain of works that are carried out sequentially;
Stages are successive periods of time during which work is performed. During the stage, work related to different processes can be performed. The activity of creating and using an automated information system for managing an economic object is based on the concept of its life cycle (LC). The life cycle is a model of the creation and use of an automated information system for managing an economic object, reflecting its various states, starting from the moment of its emergence and need for it and ending with the moment of complete withdrawal from use by all users without exception.
Traditionally, the following main stages of the AIS life cycle are distinguished:
Requirements analysis;
Design;
Programming/implementation;
Testing and debugging;
Operation and maintenance.
Let's take a closer look at the main stages of the AIS life cycle:
1. Requirements analysis is the first phase of AIS development, at which the customer’s requirements are clarified, formalized and documented. In fact, at this stage the answer to the question is given: “What should the future system do?”, And this is the success of the entire project. In the practice of creating large systems, there are many examples of unsuccessful project implementation precisely because of the incompleteness and unclear definition of system requirements.
The list of requirements for AIS should include:
1) a set of conditions under which it is expected to operate the future system (hardware and software resources provided to the system; external conditions of its functioning, composition of employees and works related to it)
2) description of the functions that the system must perform;
3) restrictions in the development process (directive deadlines for completing individual stages, available resources, organizational procedures and measures to ensure information protection).
The purpose of the analysis is to transform general, fuzzy knowledge about the requirements for the future system into precise (if possible) definitions.
The result of the stage should be a model of system requirements (that is, a system design), which means:
1) the architecture of the system, its functions, external conditions, division of functions between the hardware and software parts;
2) interfaces and separation of functions between humans and the system;
3) requirements for software and information components of the software part: necessary hardware resources, database requirements, physical characteristics of the software components, their interfaces.
The requirements model should include;
1) a complete functional model of the requirements for the future system with processing depth down to the level of each operation of each official;
2) specifications of lower level operations;
3) a package of reports and documents on the functional model, including characteristics of the modeling object, a list of subsystems, requirements for methods and means of communication for information exchange between components, requirements for the characteristics of the system’s relationships with adjacent systems, requirements for system functions;
4) conceptual information model of requirements;
5) a package of reports and documents on the information model;
6) system architecture with reference to the conceptual information model;
7) proposals for organizing a structure to support the system.
Thus, the requirements model contains functional, informational and, possibly, event (if the target system is a real-time system) models. This provides a number of advantages over the traditional model, namely:
1) Traditional development is characterized by the implementation of the initial stages using artisanal, unformalized methods. Therefore, customers and users can see the system for the first time after it has already been largely implemented. Naturally, this system will be different from the one they expected. Therefore, further iterations of its development or modification require additional (and significant) expenditures of money and time. The key to solving this problem is provided by the requirements model, which allows
Describe, “see” and adjust the future system before it is physically implemented;
Reduce the costs of system development and implementation;
Evaluate development in terms of time and results;
Reach mutual understanding between all participants in the work (customers, users, developers, programmers)
Improve the quality of the product being developed, namely: perform its functional decomposition and design the optimal structure of the integrated database.
2) The requirements model is completely independent and separated from specific developers, does not require maintenance by its creators and can be painlessly transferred to others. Moreover, if for some reason the enterprise is not ready to implement a system based on a requirements model, it can be left “on the shelf” until the need arises.
3) The requirements model can be used for independent development or adjustment of software already implemented on its basis by programmers from the enterprise automation department.
4) The requirements model can be used for automated and quick training of new employees in a specific area of the enterprise’s activities, since its technology is contained in the model.
The requirements analysis stage is the most important among all life cycle stages. It significantly influences all subsequent stages, while remaining at the same time the least studied and understood process. At this stage, firstly, you need to understand what exactly needs to be done, and secondly, document it, because if the requirements are not recorded and made available to project participants, then they do not seem to exist. At the same time, the language in which the requirements are formulated should be quite simple and understandable to the customer.
2. The development of technical specifications is carried out after the construction of the model; it contains requirements for the future system. On its basis, a technical specification is being developed to create a system that includes:
Requirements for automated workstations, their composition and structure, as well as methods and schemes of information interaction between them;
Development of requirements for technical means;
Determination of software requirements;
Development of topology, composition and structure of a local computer network;
Requirements for stages and timing of work.
3. Design. This stage provides an answer to the question: “How (in what way) will the system satisfy the requirements for it? The task of this stage
There are studies of the structure of system 1 of the logical relationships of elements, and issues related to implementation on a specific platform are not addressed here. Design is seen as an iterative process of obtaining a logical model of the system along with strictly formulated goals set for it, as well as writing specifications for the physical system that satisfies these requirements. This stage is usually divided into two sub-stages:
System architecture design, including development of the structure and interfaces of components, coordination of functions and technical requirements for components, design methods and standards;
Detailed design, which involves developing specifications for each component, interfaces between components, developing test requirements, and a component integration plan.
In other words, design is the life cycle stage, at which it is determined how the requirements for forestry, generated and recorded at the analysis stage, should be implemented. As a result, an implementation model should be built that demonstrates how the system will satisfy the requirements placed on it (without technical details). In fact, the implementation model is a development and refinement of the requirements model, namely design is the bridge between analysis and implementation.
4. Implementation (programming / adaptation). At this stage, the LES is created as a complex of software and hardware (starting with the design and creation of telecommunications infrastructure and ending with the development and installation of applications).
5. Testing and debugging. The correctness of AIS is its most important property and the main concern of developers. Ideally, 1C correctness means the absence of errors in it. However, this is impossible to achieve for most complex software products (every program contains at least one bug). Therefore, “correct” is usually understood as a software product that works in accordance with the requirements placed on it, that is, a product for which conditions under which it would not work have not yet been found.
Establishing correctness is the main goal of the life cycle stage being considered. It should be noted that the testing and debugging stage is one of the most labor-intensive, tedious and unpredictable stages of IS development. On average, for development using traditional methods, this stage takes from 1/2 to 1/3 of the total development time. On the other hand, testing and debugging pose a serious problem: in some cases, testing and debugging programs require several times more time than programming itself.
Testing is a set of procedures and actions designed to demonstrate the correct operation of an IS in specified modes and external conditions. The purpose of testing is to identify the presence of errors or convincingly demonstrate their absence, which is possible only in certain trivial cases. It is important to distinguish between testing and the related concept of “debugging”. Debugging is a set of procedures and actions that begin with identifying the very fact of the presence of an error and end with establishing the exact location, nature of this error and ways to eliminate it.
The most important and most often used in practice is the deterministic testing method. In this case, specific initial data are used as test standards, consisting of interconnected input and result values and the correct sequences of their processing. In the process of testing with given initial values, it is necessary to establish that the results of their processing correspond to the reference values.
Complex systems require a large number of tests, and the problem arises of estimating the required number and using methods to reduce them. Therefore, it is advisable to plan testing (like any other type of activity). The test plan should contain:
1) formulation of testing goals;
2) criteria for the quality of testing, allowing to evaluate its results;
3) a testing strategy that ensures the achievement of specified quality criteria;
4) resource requirements to achieve a given quality criterion according to the chosen strategy.
There are automated testing and debugging systems (Satna). They represent a complex set of algorithmic and software tools designed to automate the analysis of AIS, testing, debugging and assessment of its quality, and make it possible to facilitate the modification of AIS components, ensure the detection of errors in the early stages of debugging, and increase the percentage of errors that are automatically detected.
6. Operation and maintenance. The main objectives of this stage are:
Ensuring the stability of the system and saving information - administration;
Timely modernization and repair of individual elements - technical support;
Adaptation of the capabilities of the system, operated with the current business needs of the enterprise - system development.
These works must be included in the operational plan for informatization of the enterprise, which must be formed in compliance with all the conditions of the strategic plan. Otherwise, fragments may appear within the existing system that will make effective operation of the system impossible in the future. Nowadays, it has become common practice abroad to transfer the functions of technical support and partly administration to system suppliers or system integrators. This practice is called "outsourcing". Often, outsourcing also transfers to third parties functions such as the creation and support of backup data storage and execution centers for critical business applications that are used in the event of a natural disaster or other special conditions.
At the operation and maintenance stage, special attention should be paid to personnel training and, accordingly, planning investments in this process.
The life cycle is formed in accordance with the principle of top-down design and usually has an iterative nature: the implemented stages, starting from the very first, are repeated cyclically in accordance with changes in requirements and external conditions, the introduction of restrictions, etc. At each stage of the life cycle, a certain set of documents and technical solutions is generated, Moreover, for each stage, the documents and decisions obtained at the previous stage are the starting points. Each stage ends with verification of the generated documents and solutions in order to verify their compliance with the output.
Existing life cycle models determine the order of stages during development, as well as the criteria for transition from stage to stage. In accordance with this, the following three models ZhShch4] are most widespread:
1. The cascade model (70s - 80s) provides for a transition to the next stage after complete completion of work at the previous stage and is characterized by a clear separation of data and their processing processes (Fig. 2.6).
Rice. 2.6. Cascade IP life cycle model
2. Stage-by-stage model with intermediate control (80-85s) - an iterative development model with feedback cycles between stages. The advantage of this model is that between-stage adjustments provide less labor intensity compared to the cascade model; on the other hand, the lifetime of each stage extends over the entire development period.
3. Spiral model (86 - 90s) - focuses on the initial stages of life cycle: requirements analysis, specification design, previous and detailed design. At these stages, the feasibility of technical solutions is checked and justified by creating prototypes. Each turn of the spiral corresponds to a stage-by-stage model for creating a fragment or version of the system; on it, the goals and characteristics of the project are clarified, its quality is determined, and the work of the next turn of the spiral is planned. In this way, the details of the project are deepened and consistently specified, and as a result, a justified option is selected, which is brought to implementation (Fig. 2.7.).
Rice. 2.7. Spiral IP life cycle model
Experts note the following advantages of the spiral model:
Accumulation and reuse of software, models and prototypes;
Focus on the development and modification of the system during its design;
Risk and cost analysis in the design process.
When using the spiral model, design solutions, design tools, models and prototypes of the information system and information technology are accumulated and reused; there is a focus on the development and modification of systems and technologies in the process of their design; analysis of risks and costs in the process of designing systems and technologies is carried out.
Features of information technology design. Modern information technology is implemented in the conditions of a designed information system.
Aspects of design: technical (hardware and communication complex), software and mathematics (models and programs), methodological (a set of means for implementing management functions), organizational (description of document flow and regulations for the actions of the management apparatus), operational (a set of technological, logical, arithmetic actions, implemented automatically).
Introduction…………………………………………………………………………………..3
1. Theoretical foundations of information systems development
1.1. The concept of IS as a means of automation…………………………….5
1.2. IS information support………………………………………… 7
1.3. Russian market for information systems for recording medicines…………………….12
2. Design and development of an information system for recording medicines in a pharmaceutical organization
2.1. Infological structure of the accounting database at a transport enterprise………………………………………………………………………………………...16
Introduction
The relevance of the course work lies in the fact that all modern warehouse enterprises require automated information systems (IS). The main advantage of automation is the reduction of redundancy of stored data, and therefore saving the amount of memory used, reducing the cost of multiple operations for updating redundant copies and eliminating the possibility of inconsistencies due to storing information about the same object in different places, increasing the degree of reliability of information and increasing information processing speed; excessive number of internal intermediate documents, various journals, folders, applications, etc., repeated entry of the same information into various intermediate documents. Also significantly reducing the time is the automatic search for information, which is carried out from special screen forms in which the object search parameters are indicated.
The object of the study is a transport enterprise (freight transportation).
The subject of the study is accounting automation at a transport enterprise.
The purpose of the work is to develop an information system for vehicle fleet accounting at a transport enterprise.
To achieve this goal, it is necessary to solve the following tasks:
1. Study the theoretical foundations of information systems development
2. Design and develop an information system for accounting for a transport enterprise.
The theoretical basis of the course work was the works of domestic scientists in the field of automated information technologies, materials from periodicals, and information resources of the global Internet.
The methodological basis of the work is methods of system analysis: program, dialectical and lexical methods
The goals and objectives of the course work determined its structure. The course work consists of an introduction, two parts, a conclusion and a list of references1. Theoretical foundations of information systems
1.1. The concept of IS as a means of automation
A system is understood as any object that is simultaneously considered both as a single whole and as a collection of heterogeneous elements united in the interests of achieving set goals. Systems differ significantly from each other both in composition and in main goals. In computer science, the concept of “system” is widespread and has many semantic meanings. Most often it is used in relation to a set of technical tools and programs. The hardware of a computer can be called a system. A system can also be considered a set of programs for solving specific applied problems, supplemented by procedures for maintaining documentation and managing calculations. Adding the word “information” to the concept of “system” reflects the purpose of its creation and operation. Information systems provide collection, storage, processing, retrieval, and issuance of information necessary in the decision-making process of problems from any area. They help analyze problems and create new products.
An information system is an interconnected set of means, methods and personnel used to store, process and issue information in order to achieve a given goal.
The modern understanding of an information system involves the use of a computer as the main technical means of processing information. In addition, the technical implementation of the information system in itself will not do anything...
Information system (IS) is an interconnected set of tools, methods and personnel used for storing, processing and issuing information in the interests of achieving a set goal.
Modern information technologies provide a wide range of ways to implement IS, the choice of which is based on the requirements of the intended users, which, as a rule, change during the development process.
By an IS project we mean design and engineering and technological documentation, which provides a description of design solutions for the creation and operation of an IS in a specific software and hardware environment.
IS design is understood as the process of converting input information about an object, methods and experience in designing objects of a similar purpose in accordance with GOST into an IS project. From this point of view, IS design comes down to the consistent formalization of design decisions at various stages of the IS life cycle: planning and analysis of requirements, technical and detailed design, implementation and operation of the IS.
The scale of the systems being developed determines the composition and number of participants in the design process. With a large volume and tight deadlines for completing design work, several design teams (development organizations) may participate in the development of the system. In this case, a parent organization is identified that coordinates the activities of all co-executing organizations.
Carrying out the design of an IC involves the use by designers of a certain design technology that corresponds to the scale and characteristics of the project being developed.
Model (Latin "modulus" - measure) is a substitute object for the original object, providing the study of some properties of the latter; a simplified representation of the system for its analysis and prediction, as well as obtaining qualitative and quantitative results necessary for making the right management decision.
Modeling is the representation of an object by a model to obtain information about it by conducting experiments with its model.
For IC design they use information models, representing objects and processes in the form of pictures, diagrams, drawings, tables, formulas, texts, etc.
Information model is a model of an object, process or phenomenon in which the information aspects of the modeled object, process or phenomenon are presented.
It is the basis for the development of IS models.
The IP creation model has four stages:
1. Project sketch. P a detailed description of the goals and objectives of the project, expected profit, time resources, any restrictions, available resources, etc. It is also worth identifying a "project manager" who is responsible for the implementation of the project, and a project owner in senior management who will be the main person in the business and will support the project manager when necessary and at the very end of the project.
2. Project evaluation. This is the most important part of the project. It is where all the important decisions are made—what the systems will do, how they will operate, what hardware and applications will be used, and how they will be maintained. Most importantly, the possible costs and benefits of various actions are analyzed and the final choice is made. The general rule should be that the system should be as simple as possible. Enormous system projects can result in incredible costs. Changes made later are more expensive.
3. First, prepare a list of requirements for the system - a detailed list of what the system will do for the business and how to manage it. The needs of regular users (and other stakeholders) are studied, since only they really know what they need and how to fit it into existing activities.
4. The list includes data to be entered, main results and reports, number of users, size of information, connections with other existing systems, etc. and must be sufficiently detailed to allow the request to be sent to hardware and software suppliers.
5. At this stage we should not simply computerize existing ways of working. An information technology project is a good opportunity to think again about how best to make an information system.
6. The next stage is to look at the hardware and software requirements. Consult with potential suppliers, review other business decisions and consult with knowledgeable advisors. Some difficult decisions must be carefully evaluated. You should answer, for example, the following questions: whether to use a ready-made package of application programs or order new software. The answers will depend on the level of risk you are willing to take and how your business differs from other typical businesses.
Cost-benefit analysis is the final step before making a final decision. The costs for application programs and hardware are relatively low, especially if you use a standard package. The big costs are the time to install the system and the time to support its operation.
7. Construction and testing. One of the most underrated steps in installing any system is entering all the data into the system before it goes live.
8. Staff should ensure that the system is easy to operate. Nothing kills enthusiasm for a new system faster than a series of technical problems.
9. Project management and risk assessment. Unless the project is completely trivial, there needs to be a project manager who has enough time to work with the project and deal with the host of problems that may arise. A project is not complete until the project manager can demonstrate that the system works reliably and is profitable.
10. An important part of his role is to remain aware of the risk of the project at all times. Risks should be discussed openly, despite the temptation to bury your head in the sand and hope that everything will work out. Risk can be planned: by making alternative decisions, preparing for extreme actions, etc. An example would be software selection, where different decisions can be risky to varying degrees. There is no room for further discussion, but using the following checklist may help highlight some points.
