The life cycle of a system is the process stage, covering various states of the system, starting from the moment it becomes necessary in such a system and ending with its complete decommissioning [1] ; a finite set of common phases and stages through which a system can go through its life story [2] .
The life cycle is not a time period of existence, but a process of successive change of state due to the type of impacts produced (P 50-605-80-93) [3] .
The term "system life cycle" is usually understood as the evolution of a new system in the form of several stages, including such important stages as the concept , development, production , operation and final decommissioning [4] .
The system engineering standards describe four basic principles of life cycle modeling, namely:
- Throughout its life, a system develops through certain stages.
- At each stage of the life cycle, appropriate enabling systems should be available, only in this case the results planned for this stage can be achieved.
- At certain stages of the life cycle, attributes such as manufacturability, usability , serviceability and the ability to dispose of waste should be specified and implemented.
- The transition to the next stage is possible only if the results planned for the current stage are fully achieved.
In the full life cycle of any system, there are always typical stages, each of which has goals specific to it and contributes to the full life cycle [5] .
Content
Lifecycle Concept History
The concept of a life cycle arose at the end of the 19th century. as a complex of ideas, including the ideas of heredity and development at the level of individuals and organisms, as well as adaptation, survival and extinction at the level of individual species and entire populations of living organisms [6] .
Typical System Life Cycle Models
System life cycle models have gained significant popularity over the past two decades. Some models have evolved as additional, unique and custom research applications. In addition, software development entailed the formation of new development models, which were subsequently adopted by the system community [4] .
There is no single life-cycle model that meets the requirements of any possible task. Various standardization organizations, government agencies, and engineering communities publish their own models and technologies that can be used to construct the model. Thus, it is impractical to assert the existence of the only possible algorithm for constructing a life cycle model.
Some systems engineering experts propose considering a systemβs life cycle model based on the following three sources: the US Department of Defense (DoD) logistics management model (DoD 5000.2), the ISO / IEC 15288 standard model, and the National Society of Professional Engineers (NSPE) model ) [4] .
ISO / IEC 15288 standard lifecycle model
In 2002, the International Organization for Standardization and the International Electrotechnical Commission released the result of many years of work - the standard ISO / IEC 15288: 2002 (see the Russian-language analogue of GOST R ISO IEC 15288-2005) [7] .
According to the standard, the processes and actions of the life cycle are defined, appropriately adjusted and used during the life cycle stage, in order to fully satisfy the goals and results at this stage. Different organizations can take part in various stages of the life cycle. There is no single universal model of the life cycles of systems. Some stages of the life cycle may be absent or present depending on each specific case of system development [7] .
The following stages of the life cycle were given as an example in the standard:
- The idea.
- Development.
- Production.
- Application .
- Application Support.
- Termination and decommissioning.
In the 2008 version of the standard (ISO / IEC 15288: 2008), there are no examples of life cycle stages [8] .
US Department of Defense Standard Lifecycle Model
To manage risk in the application of advanced technologies, and to minimize costly technical or managerial errors, the US Department of Defense has developed a manual containing all the necessary principles for developing systems. These principles are included in the special list of directives - DoD 5000.
The life cycle model of the logistics management system according to the US Department of Defense consists of five stages [4] :
- Analysis.
- Technology development.
- Engineering and manufacturing development.
- Production and deployment.
- Functioning and support.
National Society of Professional Engineers (NSPE) System Life Cycle Model
This model is adapted for the development of commercial systems. This model is mainly aimed at the development of new products, usually resulting from technological progress. The NSPE model provides an alternative view of the model version of the US DoD. The life cycle of the NSPE model is divided into six stages [4] :
- Concept.
- Technical implementation.
- Development.
- Commercial validation and production preparation.
- Full-scale production.
- End product support.
Standard model of the product life cycle according to R 50-605-80-93
In the guidance document P 50-605-80-93, the life cycle of an industrial product, including military equipment, was carefully designed [3] .
The following stages are proposed for industrial civilian products:
- Research and design.
- Manufacture.
- Appeal and implementation.
- Exploitation or consumption.
As part of the life cycle of industrial civilian products, it is proposed to consider 73 types of work and 23 types of stakeholders (βparticipants in the workβ in terms of the document).
The following stages are proposed for industrial military products:
- Research and development justification.
- Development.
- Production.
- Exploitation.
- Overhaul.
As part of the life cycle of industrial military products, it is proposed to consider 25 types of work and 7 types of stakeholders (participants in the work).
Typical Software Life Cycle Model
The stages of the system life cycle and their component phases shown in the figure βSystem life cycle modelβ apply to most complex systems, including those that contain software with a significant amount of functionality at the component level. In software-intensive systems in which the software performs almost all functions (such as modern financial systems, airline reservation systems, the global Internet, and others), life cycles are usually similar in content, but often complicated by iterative processes and prototyping [4] .
The main stages of the system life cycle (Kossiakoff, Sweet, Seymour, Biemer)
As shown in the figure βSystem Life Cycle Modelβ, the system life cycle model contains 3 stages. The first 2 stages are for development, and the third stage covers post-development. These stages show more general transitions from state to state, in the life cycle of the system, and also show changes in the type and scope of activities involved in system engineering. The stages are [4] :
- concept development stage;
- stage of technical development;
- post-development stage.
Concept Development Stage
The purpose of the concept development stage is to assess new opportunities in the application of the system, develop preliminary system requirements and possible design solutions. The stage of development of a conceptual project begins with the moment of realization of the need to create a new system or modify an existing one. The stage includes the beginning of factual research, the planning period, the economic, technical, strategic and market fundamentals of future actions are evaluated. A dialogue is ongoing between stakeholders and developers [8] .
The main goals of the concept development stage [4] :
- Conduct research, establishing what is necessary for the new system, and also establishing the technical and economic feasibility of this system.
- To study the potential concepts of the system, as well as formulate and validate a set of requirements for system performance.
- Choose the most attractive system concept, determine its functional characteristics, and also develop a detailed plan for the subsequent stages of design, production and operational deployment of the system.
- To develop any new technology suitable for the chosen system concept and validate its ability to satisfy needs.
Engineering Stage
The stage of technical development involves the process of designing a system to implement the functions formulated in the concept of the system, in physical embodiment, which can be supported and successfully operated in their operating environment. Systems engineering primarily refers to the direction of development of development and design, interface management, development of test plans, and determines how differences in system performance that were not verified during testing and evaluation should be properly corrected. The bulk of engineering activities are carried out at this stage.
The main objectives of the stage of technical development are [4] :
- Performing technical development of a prototype system that meets the requirements of performance, reliability, maintainability and safety.
- Design a usable system and demonstrate its operational suitability.
Post Development Stage
The post-development phase consists of activities beyond the period of the systemβs development, but still requires significant support from system engineers, especially when unforeseen problems occur that need to be resolved as soon as possible. In addition, advances in technology often require an internal modernization of the service system, which can be as dependent on system engineering as the concept and technical development stages.
The post-development stage of the new system begins after a successful testing and evaluation of the system (acceptance testing), release into production and subsequent operational use. Until the main development is completed, systems engineering will continue to play the main supporting role [4] .
| Principal stages in the system life cycle | Stages of conceptual development in the system life cycle | Stages of technical development in the system life cycle |
Notes
- β Blanchard, Fabrycky, 2006 .
- β ISO 15704, 2000 .
- β 1 2 P 50-605-80-93, 1993 .
- β 1 2 3 4 5 6 7 8 9 10 Kossiakoff, Sweet, Seymour, Biemer, 2011 .
- β Batovrin, Bakhturin, 2012 .
- β Shirokova G.V., Klemina T.N., Kozyreva T.P. The concept of the life cycle in modern organizational and managerial research // Bulletin of St. Petersburg University. Series "Management". Ser. 8. Issue 2, 2007, p. 3-31
- β 1 2 GOST R ISO / IEC 15288, 2005 .
- β 1 2 ISO / IEC 15288, 2008 .
Literature
- Blanchard BS , Fabrycky Wolter J. Systems engineering and analysis. - 4th ed. - Prentice Hall, 2006.
- ISO / IEC 15288: 2008 Systems and software engineering - Life cycle processes
- ISO 15704: 2000 Industrial automation systems - Requirements for enterprise-reference architectures and methodologies (GOST R ISO 15704-2008 Requirements for standard enterprise architectures and methodologies)
- Kossiakoff A., Sweet WN, Seymour SJ, Biemer SM Systems Engineering Principles and Practice. - 2nd ed. - Hoboken, New Jersey: A John Wiley & Sons, 2011 .-- 599 p. - ISBN 978-0-470-40548-2 .
- Batovrin V.K. , Bakhturin D.A. Lifecycle management of technical systems. - 2012.
- GOST R ISO / IEC 15288-2005 Information technology. Systems Engineering Systems Life Cycle Processes
- P 50-605-80-93. Recommendations The system of development and putting products into production. Terms and definitions ( Link to text ).