“A subsystem is a set of classes (and possibly other subsystems) collaborating to fulfill a set of responsibilities. Although subsystems do not exist as the software executes, they are useful conceptual entities.”

Source: Object-oriented design: a responsibility-driven approach (1989), p. 30

Adopted from Wikiquote. Last update June 3, 2021. History

Help us to complete the source, original and additional information

Do you have more details about the quote "A subsystem is a set of classes (and possibly other subsystems) collaborating to fulfill a set of responsibilities. Alt…" by Rebecca Wirfs-Brock?

Rebecca Wirfs-Brock13

American software engineer 1953

Eric Trist (1909–1993) British scientist

The evolution of socio-technical systems, (1981)

“Active loose coupling occurs when a subsystem of an organization is more tightly coupled to an environmental sector than other subsystems, and a feedback loop connects environmental conditions with organizational responses. A feedback loop is present when an organizational mechanism for monitoring the environment exists, and when the state of the environment (or intended target of the organization's action) is compared to some desired state by members of the organization.”

Howard E. Aldrich (1943) American sociologist

Source: Organizations and Environments, 1979, p. 85

“The state of segmentation of the organizational system into subsystems, each of which tends to develop particular attributes in relation to the requirements posed by its relevant external environment. Differentiation, as used here, includes the behavioral attributes of members of organizational subsystems.”

Paul R. Lawrence (1922–2011) American business theorist

Source: Organization and environment: Managing differentiation and integration, 1967, p. 4

“This is a comparative study of six organizations operating in the same industrial environment. The subsystems (sales, research, and production) in each organization were differentiated from each other in terms of subsystem formal structures, the member's goal orientation, member's time orientations and member's interpersonal orientations. This differentiation was related to the requirements of the particular subenvironment with which each subsystem dealt. A relationship was found between the extent to which the states of differentiation and integration in each organization met the requirements of the environment and the relative economic performance of the organizations.”

Paul R. Lawrence (1922–2011) American business theorist

Source: "Differentiation and integration in complex organizations," 1967, p. 1

“Development of an organism from a single germ cell into a multicellular entity is a self-organizing system from any point of view and I wish to contend that this self-organizing system is a subsystem of the self-organizing system called 'evolution.”

Gordon Pask (1928–1996) British psychologist

Source: An Approach to Cybernetics (1961), p. 103-104, partly cited in: Darren Tofts, Annemarie Jonson, Alessio Cavallaro (2004) Prefiguring Cyberculture: An Intellectual History.

“The point of departure is the measurement problem, as it appears in physics; the manner in which measurements allow us to characterize subsystems; the role of such subsystems as tools in system analysis; and the relationships existing between different ways of perceiving or interacting with the same system. Our conclusions are: (1) there exists no universal family of of analytic units appropriate for the treatment of all interactions; (2) there are on the contrary many such families of analytic units, all of which are equally “real” and entitled to be treated on the same footing; (3) the appropriate use of natural interactions can enormously extend the class of physical observables accessible to us; (4) the concept of a model must be formulated, in its most general terms, as the sharing of a subsystem by two otherwise distinct systems, capable of imposing the same dynamic on an appropriate system with which they can both interact. We establish these results through a variety of terminologies which turn out to be equivalent: stability, invariance, symmetry, homeostasis.”

Robert Rosen (1934–1998) American theoretical biologist

Introduction; Quoted in: " Fundamentals of Measurement and Representation of Natural Systems by Robert Rosen http://www.panmere.com/?page_id=15" at panmere.com. <br class="br">Fundamentals of measurement and representation of natural systems. (1978)

“The term (system-of-systems) is being applied to the creation of new systems by bringing together existing operational systems under a single umbrella and, presumably, creating or adapting links and interactions between the operational systems, which become subsystems of the higher level umbrella system.”

Derek Hitchins (1935) British systems engineer

Source: Advanced Systems Thinking, Engineering and Management (2003), p. 80 as cited in: Jung-Ho Lewe (2005) An Integrated Decision-Making Framework for Transportation Architectures https://smartech.gatech.edu/jspui/bitstream/1853/6918/1/Jung-Ho_Lewe_200505_phd.pdf. p.

“When the Löwenheim-Skolem theorem is applied to particular formal systems, we obtain as special cases: Every group, field, ordered field, etc., has a countable subsystem of the same type. A more spectacular result follows from applying the theorem to set theory (a system which we shall later formalize): There is a countable collection of sets, such that if restrict the membership relation to these sets alone, they form a model for set theory (more precisely all the true statements of set theory are true in this model). In particular, within this model which we may denote by M, there must be an uncountable set. This paradox, that a countable model can contain an uncountable set, is explained by noting that to say a set is uncountable merely asserts the nonexistence of a one-one mapping of the set with the set of integers. The "uncountable" set in M set actually has only countably many members in M, but there is no one-one correspondence \underline {within} M of this set with the set of integers.”

Paul Cohen (1934–2007) American mathematician

Set theory and the continuum hypothesis, pp. 19–20 https://books.google.com/books?id=Z4NCAwAAQBAJ&pg=PA19 <br class="br">Set Theory and the Continuum Hypothesis (1966)

“A conceptual level view of an object design describes the key abstractions. While someone might think of key abstractions as being nothing more or nothing less than high-level descriptions of "candidate classes", I prefer to consider a conceptual design from a slightly different angle--I'm thinking about design at a slightly different level.
An object-oriented application is a set of interacting objects. Each object is an implementation of one or more roles. A role supports a set of related (cohesive) responsibilities. A responsibility is an obligation to perform a task or know certain information. And objects don't work in isolation, they collaborate with others in a community to perform the overall responsibilities of the application. So a conceptual view, at least to start, is a distillation of the key object roles and their responsibilities (stated at a fairly high level). More than likely (unless you form classification hierarchies and use inheritance and composition techniques) many candidates you initially model will map directly to a single class in some inheritance hierarchy. But I like to open up possibilities by think first of roles and responsibilities, and then as a second step towards a specification-level view, mapping these candidates to classes and interfaces.”

Rebecca Wirfs-Brock (1953) American software engineer

Rebecca Wirfs-Brock (2003) in " An Interview with Rebecca Wirfs-Brock Author of Object Design http://www.objectsbydesign.com/books/RebeccaWirfs-Brock.html" 2003-2005 Objects by Design, Inc: Answer to the question Can you clarify what you consider to be the essential elements of a "conceptual view".

“The essence of a software entity is a construct of interlocking concepts: [… ] I believe the hard part of building software to be the specification, design, and testing of this conceptual construct, not the labor of representing it and testing the fidelity of the representation.”

Fred Brooks No Silver Bullet

Page 182 (italics in source).
No Silver Bullet (1986)

“A subsystem is a set of classes (and possibly other subsystems) collaborating to fulfill a set of responsibilities. Although subsystems do not exist as the software executes, they are useful conceptual entities.”

Help us to complete the source, original and additional information

Rebecca Wirfs-Brock13

Related quotes

Related topics