Analysis and Selection between Alternative Solutions
Introduction
According to the Oxford English Dictionary (OED, 1973) analysis is “the resolution of anything complex into its simple elements.” This section will discuss system analysis from a Systems Approach point of view.
Analysis of Systems Overview
The four elements of System Analysis to be discussed below are: Identification of the Elements of a System, Division of Elements into Smaller Elements, Grouping of Elements, Iden-tification of the Boundary of a System, Identification of the Function of Each Element, and Identification of the Interactions Among the Elements.
Identification of the Elements of a System
The Systems Approach calls for the identification of the elements of a system. (Jackson et al., 2010, pp. 41-42) identify the kinds of elements of which a system may consist. Integral to this aspect of the Systems Approach is the principle of elements discussed above. Typical elements treated within Systems Engineering may be hardware, software, humans, processes, conceptual ideas, or any combination of these. Systems Engineering defines the properties of these elements, verifies their capability, and validates the capability of the entire system. According to (Page, 2009) in complex systems the individual elements of the system are charac-terized by their adaptability.
In a Systems Engineering context, according to (Blanchard and Fabrycky, 2006, p. 7) elements may be physical, conceptual, or processes. Physical elements may be hardware, software, or humans. Conceptual elements may be “ideas, plans, concepts, or hypotheses.” Processes may be mental, mental-motor (writing, drawing, etc.), mechanical, or electronic.
In addition to the operational elements of a system upon which focus is placed (ie. a System of Interest, SOI), ISO/IEC 15288 (2008) also calls for the identification of the “enabling” systems, utilized at various stages in the life cycle and including, for example, maintenance and others that support the operational elements to solve its problem or achieve its opportu-nity.
Division of Elements into Smaller Elements
The next aspect of the Systems Approach is that elements can be divided into smaller elements. The division of elements into smaller elements allows the systems to be grouped as discussed above under the principle of grouping and below in the Systems Approach principle of grouping of elements.
The division of elements into smaller elements leads to the Systems Engineering concept of physical architecture as described by (Levin, 2009, pp. 493-495). Each layer of division leads to another layer of the hierarchical view of a system. As Levin points out, there are many ways to depict the physical architecture including wiring diagrams, block diagrams, etc. All of these views depend on arranging the elements and dividing them into smaller elements. According the principle of recursion, these decomposed elements are either terminal elements of systems.
Grouping of Elements
The next aspect of the Systems Approach is that elements can be grouped. This grouping leads to the principle of grouping discussed above. The systems principle of grouping, dis-cussed above, leads to the identification of the subsystems essential to the definition of a system. Systems Engineering determines how a system may be partitioned and how each sub-system fits and functions within the whole system. The grouping of all the elements of a system is called the system of interest (SOI), also called the relevant system by (Checkland, 1999, p. 166). In Systems Engineering the SOI is the focus of the Systems Engineering effort. According to (Hitchins, 2009, p. 61), some of the properties of an SOI are as follows: The SOI is open and dynamic. The SOI interacts with other systems. The SOI contains sub-systems. The SOI is brought together through the concept of synthesis as described below.
Identification of the Boundary of a System
The Systems Approach principle of the identification of the boundary of a system is directly linked to the principle of boundaries discussed above. The boundary of a system is essential to Systems Engineering to determine the interaction of the system with its environment and with other systems and to determine the extent of the system of interest (SOI).
(Buede, 2009, p. 1102) provides a comprehensive discussion of the importance and methods of defining the boundary of a system in a Systems Engineering context.
Identification of the Function of Each Element
The identification of the function of an element is rooted in the concept of system functions, discussed above. The function of a system or of its elements is essential to Systems Engineering and the determination of the purpose of the system or of its elements. (Buede, 2009, pp. 1091-1126) provides a comprehensive description of functional analysis in a Systems Engi-neering context.
Identification of the Interactions among the Elements
The next element of the Systems Approach is the identification of the interactions among the elements. These interactions lead to the Systems Engineering process of interface analysis. Integral to this aspect is the principle of interactions discussed above. These interactions occur both with other system elements and also with external elements and the environment. In a Systems Engineering context interfaces have both a technical and managerial importance. (Browning, 2009, pp. 1418-1419) provides a list of desirable characteristics of both technical and managerial interface characteristics.
Linkages to other topics
The identification of the boundary of a system is essential to the Systems Engineering concept of a System of Interest (SOI).
The identification of the Functions of an element is linked to Functional Analysis within Systems Engineering.
The identification of the interactions between elements in linked to Interface Analysis within Systems Engineering.
References
Please make sure all references are listed alphabetically and are formatted according to the Chicago Manual of Style (15th ed). See the BKCASE Reference Guidance for additional information.
Citations
List all references cited in the article. Note: SEBoK 0.5 uses Chicago Manual of Style (15th ed). See the BKCASE Reference Guidance for additional information.
Primary References
JACKSON, S., HITCHINS, D. & EISNER, H. 2010. What is the Systems Approach? INCOSE Insight. International Council on Systems Engineering.
ISO/IEC 2008. Systems and software engineering -- System life cycle processes. Geneva, Switzerland: International Organisation for Standardisation / International Electrotechnical Commissions.
OED 1973. In: ONIONS, C. T. (ed.) The Shorter Oxford English Dictionary on Historical Principles. Third ed. Oxford: Oxford Univeristy Press.
Additional References
PAGE, S. E. 2009. Understanding Complexity. The Great Courses. Chantilly, VA, USA: The Teaching Company.
BUEDE, D. M. 2009. Functional Analysis. In: SAGE, A. P. & ROUSE, W. B. (eds.) Handbook of Systems Engineering and Management. Second ed. Hoboken, NJ: John Wiley & Sons.
BLANCHARD, B. & FABRYCKY, W. J. 2006. Systems Engineering and Analysis, Upper Saddle River, NJ, Prentise Hall.
LEVIN, A. H. 2009. System Architectures. In: SAGE, A. P. & ROUSE, W. B. (eds.) Handbook of Systems Engineeering and Management. Second ed. Hoboken, NJ: John Wiley & Sons.
BROWNING, T. R. 2009. Using the Design Structure Matrix to Design Program Organizations. In: SAGE, A. P. & ROUSE, W. B. (eds.) Handbook of Systems Engineering and Management. Second ed. Hoboken, NJ: John Wiley & Sons.