The difference between cascade ais and spiral ais. Life cycle of an automated information system
The stage of physical modeling should provide at the experimental level a verification of the real performance of the created AIS models and their adequacy. To implement this stage, a physical (natural) model of the AIS is being developed. Physical model of AIS- this is a set of structure, methods and means of a reduced full-scale implementation of AIS, designed to test the performance of a future system and the adequacy of its models in real conditions.
In a certain respect, the physical model of AIS has the properties of a real system. For its construction, computers, peripheral devices, documents, files, databases, data processing programs and other components necessary for the creation of AIS are involved. The physical model of AIS is reduced, i.e. this is a reduced representation of it. The reduction here is not mechanical, not arbitrary, but harmonized. It presents only those properties that the developers classified as basic, essential.
3. AIS design
Based on the developed principles, provisions, models, methods and tools for building AIS obtained at the research stage, the system is being designed.
The design stage consists of the following steps:
1) subject survey (PRO) of the existing (traditional) IP;
2) development of technical specifications for the creation of the system;
3) development of a technical project for the creation of the system;
4) development of a working draft for the creation of the system.
Provided that the existing IS is automated, there are two ways of designing: modernization of the existing AIS or its complete replacement with a newly created AIS. With relatively small volumes of design work, stages 2 and 3 can be combined.
PRO stage is carried out in order to study and analyze the features of the object - the existing traditional IS. Collection of materials for design is carried out - the definition of requirements, the study of the design object. The conditions for the functioning of the future AIS are being studied, certain restrictions on the development conditions are being established - the timing of the design stages, the available and missing resources, procedures and measures to ensure the protection of information, etc. Taking into account the preliminary studies, the development and selection of the AIS concept variant is being carried out.
Stage of development of technical specifications- a logical continuation of the missile defense stage. Materials obtained at the ABM stage are used to develop the ToR. Here, the analysis and development of the fundamental requirements for AIS by a particular customer or potential consumer group are carried out. The requirements for hardware, software, information and organizational-legal components of the AIS, etc. are formulated.
On the stage of technical design the search for the most acceptable solutions for all AIS design tasks is carried out. The purpose of this design stage is to concretize general, sometimes fuzzy knowledge about the requirements for the future system. On the this stage are defined:
purpose, tasks, functions of AIS are also considered external conditions functioning of the system, distribution of functions between its components;
AIS system parameters - interfaces and distribution of functions between the operator and the system;
configuration of all AIS subsystems forming its structure - documentary-informational, technical, software-mathematical and organizational-legal components of the system structure;
structure and database management system, linguistic tools, composition of information retrieval languages, classifiers and codifiers, methods for indexing documents and queries;
complex configuration sheet technical means AIS and their specification;
composition and characteristics of mathematical models, algorithms and AIS programs;
AIS operation diagram, technological process data processing, etc.;
job and work instructions for AIS personnel;
refined technical economic justification project.
The main part of the labor intensity of detailed design is the work on the development of algorithms and related programs.
On the detailed design stage the final refinement of those issues that at the stage of technical design for certain reasons could not be fully resolved is carried out. At this stage, a set of programs is being developed based on algorithms compiled at the stage of technical design. The structure of the database is being specified, the unified formats of documents processed in AIS technology are being adjusted.
At this stage, the programs are tested, a series of control tests with the processing of real documents, the results of testing and experimental processing, and the necessary adjustments to the programs are analyzed.
Methods and tools for designing AIS. AIS design can be performed:
third party developer. This firm has a staff of highly qualified professionals. The work is carried out on the basis of an agreement between the developer and the customer;
by staff specialists of the customer company.
A compromise solution is also possible: the customer firm can invite a consultant for the development of AIS on a contract basis.
The specific choice is determined by many factors, in particular financial condition of the customer firm, the availability of full-time specialists of the appropriate profile and level, the timing of the creation of AIS, the presence in the given or nearby region of the corresponding developer firm, specialist consultants, the firm's secrecy regime, etc.
Appropriate methods and tools are used to solve design problems. Among them, one should find such methods that would radically solve the problems of developing AIS. One such method is structural analysis. It is a method of studying a system that considers the system as hierarchical structure from its general level to the required lowest.
At the stage of pre-project survey, methods for studying the actual state of the existing (traditional) IP are used:
oral or written questioning;
written survey;
observation, measurement and evaluation;
discussion of intermediate results;
task analysis;
analysis of production, management and information
processes.
Methods for the formation of a given state are associated with the theoretical substantiation of all constituent parts AIS taking into account the goals, requirements and conditions of the customer. These include:
modeling of data processing processes;
structural design;
decomposition;
information technology analysis.
For visual presentation objects and processes of AIS, methods of graphical display of the actual and specified states are used - flowcharts, graphs, drawings, drawings, sketches, diagrams, etc.
4. AIS design automation
Computer-aided design systems - effective remedy improvement of AIS design indicators. In the field of design, a special direction has been formed - software engineering or CASE technologies (Computer-Aided Software / System Engineering - computer development system software). CASE-technologies are a set of methods for analysis, design, development and implementation of AIS, supported by a set of interconnected automation tools. CASE-technologies is a tool for system analysts, developers and programmers that provides automation of AIS design processes of various classes and values.
The main goal of CASE technology is to automate the development process as much as possible and separate the design process from coding software tools AIS.
Structural methods for building enterprise models. It is customary to call a structural method such a method of studying a system or process that begins with a general overview of the object of study, and then involves its consistent detailing. Structural methods have three main features:
The division of a complex system into parts, presented as "black boxes", each "black box" implements a certain function of the control system;
Hierarchical ordering of selected elements of the system with the definition of relationships between them;
Using a graphical representation of the relationship of system elements.
A model built using structural methods is a hierarchical set of diagrams that graphically depict the functions performed by the system and the relationships between them.
As part of the methodologies of structural analysis, the most common include the following:
SADT is a structural analysis and design technology, and its subset is the IDEFO standard.
DFD - Data Flow Diagrams.
ERD - entity-relationship diagrams.
STD - state transition diagrams.
AT IDEFO methodology four basic concepts are used: functional block, interface arc, decomposition, glossary.
The IDEFO model always begins with a process representation of a single functional block with interface arcs extending beyond the considered area. Sometimes such diagrams are provided with context help.
The goal highlights those areas of activity of the enterprise that should be considered first of all. The goal sets the direction and level of decomposition of the developed model.
AT DFD methodology the process under study is divided into subprocesses and presented as a network connected by data flows. Externally, DFD is similar to SADT, but differs in the set of elements used. These include processes, data flows, and storage.
ERD methodology used to build database models, provides a standardized way to describe data and define relationships between them. The main elements of the methodology are the concepts of "essence", "relationship" and "relationship". An entity defines basic information types, and relationships specify how these data types interact with each other. Relationships connect entities and relationships.
STD methodology is most convenient for modeling certain aspects of the system operation, due to time and response to events, for example, to implement a user request to AIPS in real time. The basic elements of STD are the concepts of "state", "initial state", "transition", "condition" and "action". By means of concepts, a description of the functioning of the system in time and depending on events is carried out. The STD model is a graphic representation - a diagram of the system's transitions from one state to another.
Object-oriented methods for constructing control system models. These methods differ from structural methods by a higher level of abstraction. They are based on the representation of the system as a set of objects interacting with each other by exchanging data. As objects subject area concrete objects or abstract entities can serve - an order, a client, etc. The most significant method is G. Buch. This is an object design technique with elements of object analysis, which has four stages:
1) development of a hardware diagram showing processes, devices, networks and their connections;
2) definition of a class structure that describes the relationship between classes and objects;
3) development of diagrams of objects that show the relationship of an object with other objects;
4) development of software architecture that describes the physical design of the system being created.
The vast majority of existing methods of object-oriented analysis and design include both a modeling language and tools for describing modeling processes.
The object-oriented approach is not opposed to the structural approach, but can serve as its complement.
5. Construction and implementation of AIS
After the complete completion of the design work, the stage of building the AIS begins. Building AIS is a set of organizational and technical measures for the implementation of the AIS project. Among such measures are financial, informational, technical, programmatic, legal, organizational measures:
Identification of funding sources and allocation of funds for procurement necessary equipment provided by the project - "AIS equipment specification sheet";
Selection of suppliers and conclusion of contracts for the supply of equipment;
Allocation of premises for deployment of AIS and its preparation for installation of equipment;
Placement, assembly, installation, configuration of AIS equipment in accordance with the project;
Selection, organization and training of categories of regular AIS personnel to perform relevant work to ensure the functioning of AIS;
Performance of work on quality control of equipment (control, testing). If defects are found - registration and presentation of complaints to suppliers;
Software installation and performance of work on testing the AIS software package. Subject to detection of defects - taking measures to eliminate them;
Filling the database, solving test cases for the entire range of AIS tasks in accordance with the project. If deficiencies are found, measures are taken to eliminate them. If no deficiencies are found - preparation of documents for putting the AIS into trial operation.
The composition of measures and their sequence reflect the main checkpoints in the construction of AIS. The construction of each specific system will have its own specifics both in terms of the nature of the tasks and their sequence. Features of the construction are determined by the nature of the AIS, the organizational level of the AIS application, the mode of operation, the amount of funding, etc.
One of the important conditions for the effectiveness of AIS is the implementation of a complex of works for its implementation. The introduction of AIS begins with the fact that the head of the customer firm issues an order for the implementation of the system indicating the main stages, the timing of their implementation, responsible executors, resource support, the form for presenting the results of implementation, the person responsible for monitoring the execution of the order, etc. The order may contain an implementation plan with indicating the work in the following stages:
1) documenting results of commissioning of equipment, as well as control tests of a set of system tasks;
2) training of personnel in AIS technology and study of relevant sections project documentation;
3) carrying out trial operation of the system, analysis and correction of design errors and execution of documentation based on the results of trial operation;
4) delivery of AIS to production operation with the relevant documentation.
Thus, at the first stage, a program of control tests of the AIS as a whole is being developed. At the second stage, the developer and the customer organize training for personnel involved in the operation of the AIS. At the third stage, the pilot operation of the system is carried out. Depending on the content and scope of AIS tasks, trial operation lasts from three to six months.
The introduction of AIS is a rather difficult task both in organizational and technical aspects. The customer must prepare the implementation of the system. This condition requires certain organizational, professional and psychological efforts on the part of the personnel of the customer company, to some extent involved in the operation of the AIS. The administration of the company must provide such conditions under which the team of the company will have a positive attitude towards the implementation of the system and help its implementation, development and development. Then it will be possible to assume that the goal of introducing and operating AIS at the enterprise will be achieved.
6. The technique for calculating the technical economic efficiency automated information processing
One of the principal sections of the AIS project is the feasibility study of the AIS in general and the processes of automated processing of economic information in particular. This requires appropriate calculations of technical and economic efficiency.
The economic efficiency of automated data processing is ensured by the following main factors:
high speed performing operations for the collection, transmission, processing and issuance of information, the speed of technical means;
Maximum reduction of time to perform individual operations;
Improving the quality of data processing and information received.
The overall efficiency of automated problem solving is directly dependent on the reduction in data processing costs and is a direct economic efficiency. Achieving the effect of system-wide solutions to improve the quality of user information service provides indirect economic efficiency.
Direct economic efficiency indicators are determined by comparing the costs of data processing for several design options. In essence, this is a comparison of two options - basic and designed. The existing system of automated or traditional (manual) data processing is taken as the basic version, and the result of the modernization of the existing system or a newly developed AIS is taken as the designed version.
The absolute indicator of the economic efficiency of the developed AIS project is the reduction in annual cost and labor costs for the technological process of data processing compared to the basic version of the TPOD.
Saving financial costs due to automation of data processing is determined based on the calculation of the difference in costs of the basic and projected data processing options using the formula:
C e \u003d C b - C p (1)
where C e - the amount of cost reduction for data processing;
C b - costs for the base case;
C n - costs for the projected option.
The relative indicator of the economic efficiency of the AIS project is the cost efficiency ratio (K e) and the cost change index (I c).
K e \u003d C e / C b * 100% (2)
The cost efficiency ratio shows what part of the costs will be saved with the projected AIS option, or by how many percent the costs will be reduced.
The value of the cost change index can be determined by the formula:
I s \u003d C e / C b. (3)
This index indicates how many times the cost of data processing will be reduced during the implementation of the AIS project.
When implementing an AIS project, it is necessary to take into account additional capital costs, the value of which (K 3) can be determined by the formula:
K 3 \u003d K p - K b (4)
where K p and K b - capital costs, respectively, of the designed and basic data processing systems.
Efficiency capital costs is determined by the payback period (T) of additional capital costs for the modernization of IS:
T \u003d K 3 / C e (5)
E \u003d C e / K 3 \u003d 1 / T. (6)
Along with the calculation of cost costs, it is useful to obtain indicators of the reduction in labor costs for data processing. The absolute indicator of labor cost reduction (t) is the difference between the annual labor costs of the basic and designed data processing options:
t = T b. – T p (7)
where T b. and T p - the annual labor intensity of operation, respectively, of the basic and designed options for data processing.
The value of the relative indicator of labor cost reduction can be displayed by the labor cost reduction coefficient (K):
K t \u003d t / T b. (eight)
The index of change in labor costs (I t) characterizes the growth in labor productivity due to the development of a more labor-saving version of the data processing project, it can be determined by the formula:
I t \u003d T b / T p. (9)
The absolute indicator of labor cost reduction (P) is used to determine the potential release of labor resources (performers) from the data processing system:
P \u003d (t / T f) * f (10)
where T f is the annual fund of time of one performer employed in data processing technology;
f is a coefficient reflecting the possibility of a complete release of workers, at the expense of the time fund of which the value of t was calculated.
The definition of direct savings from the implementation of the projected (modernized) data processing system is carried out on the basis of a comparison of indicators that reflect labor and cost costs for operations of both the traditional and the projected data processing system.
Saving labor costs (E tz) in the automated processing of information on the project can be determined by the formula
E tz \u003d T o6sch - T owls (11)
where T o6sh is the complexity of data processing in the traditional way with the base case;
T owls - the complexity of automated data processing in the design version.
The financial cost savings from the implementation of a project data processing option compared to a manual base case can be determined in a similar way.
The collection of initial data for substitution into the above formulas and the performance of calculations to determine the economic efficiency is carried out by registering and measuring the relevant parameters at the stages of the technological process of data processing. In addition, initial data for a long period can be obtained by analyzing the registration (technological) logs of the AIS controller and other forms of registration.
Model life cycle- a structure that determines the sequence of execution and the relationship of processes, actions and tasks performed throughout the life cycle.
There are two main lifecycle models that are most widely used:
cascade model (70-85 years);
· spiral model (86-90).
Cascade model
The cascade method is the division of the entire development into stages, and the transition from one stage to the next occurs only after the work on the current one is fully completed (Fig. 2).
Advantages of using the waterfall approach:
· at each stage, a complete set of project documentation is formed that meets the criteria for completeness and consistency;
· the stages of work performed in a logical sequence allow you to plan the timing of the completion of all work and the corresponding costs.
The cascading approach has proven itself well when building information systems, for which at the very beginning of development it is possible to formulate all the requirements quite accurately and completely. Complex computational systems, real-time systems and other similar tasks fall into this category.
Fig.2 Schematic of the Waterfall Approach
However, in reality, in the process of creating an IS, there is a constant need to return to previous stages, clarify or revise earlier. decisions taken. The actual process of creating an information system takes next view(fig.3):
Fig.3 The real process of creating an IS based on a waterfall model
One of the names used in the Western literature for such a scheme of work organization: "waterfall model" (waterfall model).
The main disadvantage of the cascade approach is a significant delay in obtaining results. Models (both functional and informational) of an automated object may become obsolete simultaneously with their approval. Another drawback is that such an information system design leads to primitive automation (in fact, “mechanization”) of the existing production activities of workers.
In the spiral model of the life cycle (Fig. 4), emphasis is placed on the initial stages of the life cycle: analysis and design. The feasibility of technical solutions is tested by creating prototypes.
Fig 4.
Each turn of the spiral corresponds to the creation of a new fragment or version of the information system, on which the goals and characteristics of the project are specified, its quality is determined, and the work of the next turn of the spiral is planned. One turn of the spiral in this case is a complete project cycle cascade type. This approach was also called "Continuing Design". Later, the project cycle additionally began to include the stages of development and testing of a prototype system. It was called: "rapid prototyping", rapid prototyping approach or "fast-track".
However, the use of such methods, along with a quick effect, reduces the manageability of the project as a whole and the interoperability of various fragments of the information system. The main problem of the spiral cycle is determining the moment of transition to the next stage. The transition proceeds according to plan, even if not all planned work is completed. The plan is drawn up on the basis of statistical data obtained in previous projects, and personal experience developers.
AIS Life Cycle Models - A structure that defines the sequential implementation of processes, actions, tasks performed throughout the life cycle and the relationship between these processes.
cascade model. The transition to the next stage means the complete completion of the work at the previous stage. The requirements defined at the requirements formation stage are strictly documented in the form of terms of reference and fixed for the entire duration of the project development. Each stage culminates in the release of a complete set of documentation sufficient for development to be continued by another development team.
Project stages according to the waterfall model:
1. Formation of requirements;
2. Design;
3. Development;
4. Testing;
5. Introduction;
6. Operation and maintenance.
Advantages:
-Full and agreed documentation at each stage;
-Determined order of work sequence;
- Allows you to clearly plan the timing and costs.
Disadvantages:
-Significant delay in obtaining ready-made results;
-Mistakes at any of the stages are detected at subsequent stages, which leads to the need to return and re-register project documentation;
- Difficulty in project management.
spiral model. Each iteration corresponds to the creation of a fragment or version of the software, it clarifies the goals and characteristics of the project, evaluates the quality of the results obtained, and plans the work of the next iteration.
Each iteration - completed development cycles in the form of the 1st version of the AIS.
Iteration steps:
1.Formation of requirements
3.Design
4.Development
5.Integration
At each iteration, the following are evaluated:
The risk of exceeding the terms and cost of the project;
The need to perform another iteration;
The degree of completeness and accuracy of understanding the requirements for the system;
The expediency of terminating the project.
Advantages:
-Simplifies the process of making changes to the project;
- Provides greater flexibility in project management;
- The possibility of obtaining a reliable and stable system, because errors and inconsistencies are found at each iteration;
- Influence of the customer on the work in the process of checking each iteration.
Disadvantages:
-Complexity of planning;
-Intense mode of work for developers;
-Work planning is based on experience and there are not enough metrics to measure the quality of each version.
Requirements for the technology of design, development and maintenance of AIS
Design Technology- defines a combination of three components:
- a step-by-step procedure that determines the sequence of technological design operations;
- rules used to evaluate the results of technological operations;
- submission of design development for examination and approval.
Technological instructions, which make up the main content of the technology, should consist of a description of the sequence of technological operations, the conditions depending on which one or another operation is performed, and descriptions of the operations themselves.
The technology for designing, developing and maintaining IS must meet the following general requirements:
The technology must support the full software lifecycle;
The technology should ensure the guaranteed achievement of the goals of IS development with a given quality and at a specified time;
The technology should provide the possibility of conducting work on the design of individual subsystems in small groups (3-7 people). This is due to the principles of team manageability and productivity increase by minimizing the number of external links;
The technology should provide for the possibility of managing the project configuration, maintaining versions of the project and its components, the possibility of automatically issuing project documentation and synchronizing its versions with project versions;
The use of any technology for the design, development and maintenance of IS in specific organization and a specific project is impossible without the development of a number of standards (rules, agreements) that must be observed by all project participants. To such standards include the following:
- design standard;
- standard for the design of project documentation;
- user interface standard.
Development requirement
- Performing work on the creation of software;
Preparation for the introduction of AIS;
Control, testing of the main indicators of the project.
Accompanying Requirements
Completion of the implementation of CIS should be accompanied by the publication of the system administrative regulations and job descriptions defining the order of functioning of the organization. From the moment the information system is put into operation, operation takes place on the basis of the "Regulations for the functioning of the information system" and a number of regulations. Maintenance of the system and its uninterrupted operation is carried out by a subdivision of the organization authorized by the relevant order. The completion of the information system after commissioning is carried out in accordance with individual projects and terms of reference.
In the process of maintaining CIS, the task is to maintain its viability. The viability of the CIS is largely determined by how it corresponds to the real tasks and needs of the university, which are changing during the life cycle of the CIS.
JCIS- this is the period of creation and use of IS, starting from the moment the need for IS arises and ending with the moment it is completely out of operation.
Information system life cycle stages:
1. Pre-project survey:
collection of materials for design, while highlighting the formulation of requirements, from the study of the automation object, preliminary conclusions of the pre-design version of the IS are given;
· Analysis of materials and development of documentation, a feasibility study with a technical assignment for the design of IS is mandatory.
2. Design:
2.1 preliminary design;
· selection of design solutions on aspects of IS development;
· description of real IS components;
preparation and approval of the technical project (TP).
2.2 detailed design:
selection or development of mathematical methods or program algorithms;
Adjustment of database structures;
Creation of documentation for the delivery and installation of software products;
selection of a complex of technical means with documentation for its installation.
2.3 development of the techno-working project of IP (TRP).
2.4 development of a methodology for the implementation of management functions using IS and a description of the regulations for the actions of the management apparatus.
3. IS development:
Obtaining and installing hardware and software;
testing and fine-tuning of the software package;
· Development of instructions for the operation of software and hardware.
4. Putting the IS into operation:
input of technical means;
input of software;
· training and certification of personnel;
trial operation;
Delivery and signing of acts of acceptance and delivery of works.
5. IP operation:
daily operation;
General support of the entire project.
Information system life cycle models:
· waterfall model- proposes the transition to the next stages after the full implementation of the work on the previous stage. The model demonstrates the classical approach in any application areas;
· iterative model- staged model with intermediate control and feedback loops. The advantage of this model is step-by-step adjustments, which provide less labor intensity compared to the cascading one. However, the lifetime of each of the stages is calculated for the entire development period;
· spiral model - this model focuses on the initial stages of analysis and design. This model is an iterative development process, where each iteration (cycle) is a complete development cycle leading to the release of a product version (IS project version), which is improved from iteration to iteration to become a meaningful information system. At the same time, each turn of the spiral corresponds to a step-by-step model for creating an information system. That. the substantiated version of the IS is deepened and consistently concretized, which is subsequently brought to implementation.
The main ways to build an IS:
· development of a system "under itself";
use of prototypes - instead of a complete system, a prototype is created that meets the basic needs of users:
Definition of basic queries;
Creation of a working prototype;
Using a working prototype;
Revision and improvement of the prototype;
Work with the final version of the prototype;
use of services third party organization to transfer the management functions of IS - the organization uses a specialized firm that performs management functions for the functioning and development of the company's IS.
Pros:
· guaranteed quality of service;
· saving Money;
· human resources.
Minuses:
· not cheap;
· information leak;
· addiction;
Loss of control over IT.
The management system of an economic object can be considered as a combination of two interrelated elements (two components): subject of management(SU) and control object(OU).
Subject of management It is a management apparatus that combines employees who develop plans, develop requirements for decisions made, and also control their implementation.
Control object is a direct enterprise that carries out the implementation of the tasks assigned to it. The task of the control object includes the implementation of plans developed by the administrative apparatus, i.e. implementation of the activities for which the management system was created.
The subject of control and the object of control are connected by direct and feedback. The direct connection is expressed by the flow of directive information sent from the administrative apparatus to the control object, and the reverse is the flow of reporting information on the implementation of the decisions made, sent to reverse direction(see fig. 12).
Directive information is generated by the administrative apparatus in accordance with the goals of management and information about the current economic situation, about environment. Reporting information is generated by the control object and reflects the internal economic situation, as well as the degree of influence of the external environment on it (delays in payments, power outages, weather, public political situation in the region, etc.). Thus, external environment affects not only the object of management: it also supplies information to the administrative apparatus, whose decisions depend on external factors(state of the market, presence of competition, interest rates, inflation rate, tax and customs policy).
The relationship of information flows (P and O), means of processing, transmitting and storing data, as well as employees of the administrative apparatus performing data processing operations, constitutes the information system of an economic object.
The need for management arises when it is necessary to coordinate the activities of members labor collective united to achieve their local and global goals. Initially, any goal is of a generalized nature, and only in the process of refinement is it formalized by the administrative apparatus in the form of target functions.
In the process of managing an economic entity, operational , tactical and strategic decisions. In accordance with this, it is usually said that the administrative apparatus consists of three levels of management: operational, middle and higher.
On the highest level management of an economic object managers are located. They define the goals of management, foreign policy, material, financial and labor resources, develops long-term plans and strategies for their implementation. Their competence usually includes conducting an analysis of the market, the level of competition, the conjuncture and the search for alternative strategies for the development of the enterprise in case threatening trends are identified in the area of its interests.
On the middle level of management of an economic entity executive managers are located. At this level, the focus is on developing tactical plans, monitoring their implementation, tracking resources, and developing management directives to bring the enterprise to the level required by the plans.
On the operational level of management of an economic object there are managers structural divisions(departments, services, workshops, etc.). At this level, plans are implemented and progress reports are made. The main task of operational management is to coordinate all elements production process in time and space with the required degree of detail.
At each of the levels of management of an economic object, work is performed that provides management in a complex. These activities are called functions. Depending on the goals, functions of varying degrees of generality can be distinguished. The following functions are typical: planning , accounting and the control , analysis and regulation .
Planning- a function through which the goal of management is realized in an ideal form. Planning occupies a significant place in the activities of top management, less - at the middle and minimal - at the operational level. Planning at the highest level of management concerns future problems and is oriented to the long term. At the middle level, planning is carried out for a shorter period, while the plan of the highest level of management is detailed. The indicators at this level are more accurate. Operational management involves the most detailed study of the plan.
Accounting and control - functions aimed at obtaining information about the progress of the enterprise, checking the compliance of the results achieved with the planned ones. Accounting is divided into operational, accounting and statistical. Accounting, in turn, can be divided into financial and managerial. Accounting is mainly carried out at the operational and middle levels of management. There is no accounting at the highest level of management, however, on its basis, the analysis of the results of production and the regulation of its course are fully carried out.
Analysis and regulation - this is a comparison of actual indicators with normative (directive, planned), determination of deviations that go beyond the permissible parameters, establishing the causes of deviations, identifying reserves, finding ways to correct the situation and making a decision to bring the control object to a planned trajectory. An effective tool for identifying the causes of deviations is factor analysis, and to find ways out of this situation, expert systems.
The relationship between the levels of management and the functions they perform in terms of the amount of work performed is presented in Table 7.
H a fig. 12 shows the relationship between the main stages of the process of managing an economic object.
Canonical AIS Design
Development and design AIS begins with the creation of a conceptual model for using the system. First of all, the feasibility of creating a system, its specific functions and tasks to be automated. An assessment should be made not only of the goals, but also of the possibilities of creating a system. Further, the analysis of requirements for AIS, detailed design, the relationship of stages, programming and testing, minimization of losses during the transition from one level of information presentation to another, integration into the existing system, implementation and support are carried out.
There are three classes of design methodologies AIS:
· conceptual modeling of the subject area;
Identification of requirements and specification of the information system through its prototyping;
· system architecture of software tools supported by CASE-technology tools (CASE - Computer Aided Software Engineering - technology for creating and maintaining software for various systems).
The stage of creating an automated system - part of the AS creation process established normative documents and ending with the release of documentation for the NPP, which should contain a model of the system at the level of this stage, the manufacture of non-serial components or the acceptance of the NPP into operation.
Each stage is singled out for reasons of rational planning and organization of work and must necessarily end with a certain result. The content of the documentation at each stage is determined by the composition and specifics of the work.
GOST 34.601-90 defines eight stages for creating automated systems:
- Formation of requirements for AS.
- Development of the AS concept.
- Technical task.
- Preliminary design.
- Technical project.
- Working documentation.
- Commissioning.
- AC support.
Stages 1, 2, 3 refer to the first period, stages 4, 5, 6 - to the second period, stages 7, 8 - to the third.
In the pre-project period, a feasibility study (FS) is developed and technical task(TOR) for system design. During this period, at the stage of formation of requirements for the NPP, three stages of work are carried out:
- examination of the object of the subject area and justification of the need to create a system;
- formation of user requirements for the system;
- drawing up a report on the work performed and an application for the development of the system.
- study of the object;
- carrying out research work;
- selection of a variant of the system concept from several developed ones;
- preparation of a report on the work performed.
Terms of Reference (TOR) - this is a list of the main operational, technological, economic and other requirements that the designed object must satisfy at all stages of its existence. After the approval of the TOR, the second period of the creation of the NPP begins - the period of system design.
Design - the process of a reasonable choice of system characteristics, the formation of logical-mathematical and economic-mathematical models, the development of documentation.
At the stage of creating a draft design, at the 1st stage, preliminary design solutions for the system and its parts are developed, at the 2nd stage, the documentation for the NPP and its parts.
At the 5th stage, when creating a technical project, development is carried out in four stages:
- design solutions for the system and its parts;
- documentation for the NPP and its parts;
- documentation for the supply of products for the acquisition of nuclear power plants and technical specifications for their development;
- tasks n# design in adjacent parts of the project of the automation object.
At the 7th stage, the system is put into operation in eight stages:
- preparation of the automation object for the input of the AU;
- staff training;
- completing the AU with software, hardware, information tools and products;
- construction and installation works;
- commissioning works;
- preliminary tests;
- trial operation;
- acceptance tests.
In order to improve the management of the design process, each stage is detailed, that is, it is divided into stages.
The stage of creating an automated system is part of the stage of creating the AS, determined by the nature of the work, its result or the specialization of the performers.
Modern system design methodologies should provide a description of automation objects, a description of the functionality of the AIS, a project specification that guarantees the achievement of the specified system characteristics, a detailed plan for creating a system with an assessment of the development time, and a description of the implementation of a particular system.
AIS life cycle
At the core of creation and use AIS lies the concept of life cycle (LC).
The life cycle is a model for the creation and use of AIS, which reflects the various states of the system from the moment it appears in a given set of tools to the moment it is completely out of use.
For AIS, the following main stages of their life cycle are conditionally distinguished:
1. analysis - determining what the system should do;
2. design - determining how the system will function: first of all, the specification of subsystems, functional components and how they interact in the system;
3. development - the creation of functional components and individual subsystems, the connection of subsystems into a single whole;
4. testing - checking the functional and parametric compliance of the system with the indicators determined at the analysis stage;
5. implementation - installation and commissioning of the system;
6. support - ensuring the regular process of operating the system at the customer's enterprise.
The stages of development, testing and implementation of AIS are denoted by a single term - implementation.
At each stage of the life cycle, a certain set of technical solutions and documents reflecting them are generated, while for each stage the documents and decisions made at the previous stage are the initial ones.
Existing life cycle models determine the order of execution of stages in the process of creating a system, as well as the criteria for moving from stage to stage. The most widespread are the following models.
Cascade model involves the transition to the next stage after the completion of the work of the previous stage. This model is used in the construction of AIS, for which at the very beginning of development it is possible to formulate all the requirements quite accurately and completely. This gives developers the freedom to implement them as best they can from a technical point of view. This category includes complex settlement systems, real-time systems, and others. However, this approach has a number of disadvantages, primarily due to the fact that the actual process of creating a system never fully fits into a rigid scheme. For example, in the process of creating software, there is a need to return to previous stages and clarify or revise previously made decisions.
spiral model relies on the initial stages of the life cycle: analysis, preliminary and detailed design.
Each turn of the spiral corresponds to a step-by-step model for creating a fragment or version of the system, on which the goals and characteristics of the project are specified, its quality is determined, and the work of the next turn of the spiral is planned. The main problem is determining the moment of transition to the next stage. To solve it, it is necessary to introduce time limits for each of the stages of the life cycle. The transition is carried out in accordance with the plan, which is compiled on the basis of statistical data obtained in previous projects and the personal experience of the developers. The disadvantage of this approach is the unresolved issues and errors made at the stages of analysis and design. They can lead to problems in subsequent stages and even to the failure of the entire project. For this reason, analysis and design must be carried out with particular care.