The system design is based on the results of the system analysissystem science The process of designing a new system that can meet the required goals (or objectives) to the maximum extent.System design content, including determinationsystem function, design guidelines and methods, generate ideal systems and draft, and make amendments to the draft through collecting information to generate optionsdesign scheme, willSystem decompositionFor severalSubsystem, for subsystem and overall systemdetailed design The evaluation is carried out, and the system scheme is demonstrated and the performance effect is predicted.[1]
Chinese name
system design
Foreign name
System design
Design method
Induction, deduction
Purpose
The process of designing a new system that meets the requirements
Design principles
Scalability, ease of use and phased development principles
During system design, the object system to be designed and the surrounding objectSystem environmentConsidering together, the former is called the internal system, and the latter is called the external system. There is a relationship of mutual support and mutual restriction between them. The combination of the internal system and the external system is called the overall system.Therefore, the thinking principle of combining internal design with external design must be adopted in the system designHuman factorThe overall optimal system is designed based on the comprehensive consideration of all aspects of material media.The system design should adopt decomposition, synthesis and feedbackWorking methods。No matter how bigcomplex system , first it needs to be decomposed into several subsystems or elements, which can be decomposed fromStructural elementsFunctional requirementstime series、Space configurationAnd standardize its characteristics and performance to form an optimal subsystem, and thenoverall designSo as to get the optimal system.In this process, fromDesign planFrom the beginning to the design of a satisfactory system, it is necessary to carry out phased and overallComprehensive evaluationAnd modify and improve the work accordingly.wholedesign phase It is a comprehensive feedback process.[1]
Two methods are usually used in system design: one isInduction, the other isDeductive method。The procedure of applying inductive method to system design is: first, collect the system design data of existing and past similar systems as far as possible;Based on the analysis and research on the design, manufacturing and operation of these systemsFunctions of the systemIt is required to make multiple selections, then make corresponding corrections to a few similar systems, and finally obtain an ideal system.Deduction is a kind ofaxiomatic method , that is, starting from the general rules and principles, according to the knowledge and experience of designers, select the elements that can meetsystem functionAnd then combine these elements in a certain form (seeSystem structure）To create a new system with the required functions.In the practice of system design, these two methods are often used together.
origin
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The term System comes fromAncient GreekIt means that parts form a whole.Ancient Greek philosopherDivide the world into water, fire, earth and airElement compositionIn ancient China, the "five elements" theory of gold, wood, water, fire and earth was put forward.Both East and West regard the world as a system.Although various systems are different, they all have a common feature.First of all, each system contains manySubsystemThe subsystem consists of some smaller componentssystem composition The latter includes some smaller systems.Secondly, many subsystems that constitute a system and smaller small systems are interconnected and constrained to form a whole system for a common goal.This system is subordinate to a larger system as a whole.We can define "system" as consisting of several components that interact and depend on each otherPartial combinationHaving a specific functionOrganic entirety。[2]
First put forward“system theory”It's AmericanAustriatheorybiologistLudwigVon Bertalanffy (1901-1972).In 1937, he was in the United StatesUniversity of ChicagoPhilosophy ofsymposiumTheGeneral system theoryConcept.Bertalanffy believes that any system is an organic whole, which is not a mechanical combination or simple addition of various parts. The overall function of the system is a new quality that each element does not have in an isolated state.another useAristotle"The whole is greater than the sum of parts"entiretyOppose the view that good overall performance of elements must be good.At the same time, he also believes that each element in the system does not exist in isolation, but each element is in a certain position in the system and plays a specific role.The elements are interrelated and form an indivisible whole.Elements are elements in the whole. If elements are separated from the whole, they will lose their role.[2]
Modern DesignGreat changes have taken place in our environment, and the factors affecting design are more complex. The previous method of relying on designers' intuition and experience to carry out design has been greatly challenged."Systematic thinking is non-linear, focusing on the exploration of vertical and horizontal and multi-directional problems, and its thinking is horizontal or even three-dimensional." Therefore, system design needs to take the object as a whole with a certain purpose.System design is the idea of reasonable design, development and application of the systemMethodology"The object is regarded as a system composed of multiple factors, and the creativity is launched on this basis".[2]
Design principles
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The general principle of system design is to ensure the systemdesign goal And on this basisTechnical resourcesThe best application is achieved.The following principles shall be followed in system design.[3]
systematicness
The system is an organic whole.Therefore, in the system design, it is necessary to consider from the perspective of the whole system, so that the system has a unified information codedata organization Methods, unified design specifications and standards to improve the system'sdesign quality 。[3]
Economy
EconomyThe principle is to meetsystem requirements On the premise ofExpenses。On the one hand, we should not blindly pursue the advanced technology in the system hardware investment, but should take meeting the system needs as the premise.On the other hand, unnecessary complexity should be avoided in the system design, and each module should be as simple as possible.[3]
reliability
Reliability is bothevaluation system An important indicator of design quality is also a basic starting point of system design.Only when the designed system is safe and reliable can it play its due role in practice.A successfulmanagement information systemsMust have high reliability, such as safetyConfidentiality、Error detectionAnd error correction capabilityantiviralCapability, systemResilienceEtc.[3]
Management acceptable
Whether a system can play a role and have strong vitality depends to a large extent on whether it is acceptable in management.Therefore, the user's business type and user'sBasic management work, user'squality of personnel、interfaceIt is influenced by many factors, such as the friendliness of the system and the difficulty of mastering the system operation.Therefore, these factors must be fully considered in the system design to design a system acceptable to users.[3]
method
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The system design methods mainly include: structured life cycle method (also called waterfall method), prototyping method（Iterative method)、Object oriented method。According to the time process, the development methods are divided intoLife cycle methodandPrototype methodIn fact, there are manyIntermediate stateMethod.The prototype method can be divided into experimental prototype method and evolutionary prototype method according to the way of processing prototype results.The test prototype method only uses the prototype as a test tool, and then throws it away after the test, and makes a new system according to the test conclusions.Evolutionary prototype rules retain the trial results and become part of the final system.According to the analysis elements of the system, development methods can be divided into three categories: (1) Processing Oriented (PO);(2)Data orientedDataOriented (DO);(3) Object oriented method（Object Oriented，OO)。[4]
Two methods are usually used in system design: one isInductionThe other is the deductive method. The program of applying inductive method to system design is: first, collect the system design data of existing and past similar systems as far as possible;On the basis of analysis and research on the design, manufacturing and operation of these systems, multiple selections are made according to the functional requirements of the designed systems, and then a few similar systems are modified accordingly, finally an ideal system is obtained.[4]
essential factor
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The so-called system design is based on the system analysisSystematic thinkingAnd optimization require comprehensive application of knowledge, technology and experience of relevant disciplinesdetailed design Such links shall be implemented to specific work or projects to create artificial systems that meet the design purpose.staysystem developmentDuring the process or the whole system life cycle, system analysis focuses on answering the question of "what to do", while system design focuses on solving the question of "how to do".The system design is generally divided into working systems (such asproduction system 、Organizational systemDesign, information system (such asmanagement information systems、decision support system）Design and engineering system design, etcindustrial engineeringIt is widely used in practice.When designing any system, the following basic problems or elements of system design should be considered.[5]
(1) System function: mainly refers to the purpose of designing the system and the expectations and requirements for the results of all aspects of the designed system.[5]
(2) Input and output of the system: it is necessary to clarify what needs to be processed and transformed into the system and the form, nature and quantity of output results.[5]
(3) System procedures and levels: it is required to specify the necessary transformation links and system feedback experienced by the system from input to outputcontrol mode 。[5]
(5) System media: mainly refers to the means used in the whole process of transforming inputs, such as equipment and tools in the production system, computers in the information system, etc.[5]
(6) Human factor in the system: This is one of the fundamental conditions to ensure the normal and efficient operation of the system, and the design should focus on the human factorSubjective initiativeAnd man-machineBest Fit。[5]
