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Abstraction (computer science) - Wikipedia, the free encyclopedia An example of this abstraction process is the generational development of programming languages from the machine language to the assembly language and the high-level language. Data abstraction is the enforcement of a clear separation between the abstract properties of a data type and the concrete details of its implementation. Object-oriented languages are commonly claimed to offer data abstraction; however, their inheritance concept tends to put information in the interface that more properly belongs in the implementation; thus, changes to such information ends up impacting client code, leading directly to the fragile base class problem. en.wikipedia.org /wiki/Abstraction_(computer_science)   (2915 words)

Level of abstraction - Wikipedia, the free encyclopedia In computer science, an abstraction level (or abstraction layer) is a generalization of a model or algorithm, away from any specific implementation. The simplification provided by a good abstraction layer allows for easy reuse by distilling a useful concept or metaphor so that situations where it may be accurately applied can be quickly recognized. Frequently abstraction layers can be composed into a hierarchy of abstraction levels or abstraction layers. en.wikipedia.org /wiki/Level_of_abstraction   (248 words)

Levels of Indirection Another way to describe this level of abstraction is to note that it can be calculated with the simplest of electronic calculators, in which you just see a number of the screen and add, subtract, multiply, or divide it with other numbers. Level Three: Indexed Variables Now we add one more level of abstraction: we think in terms of a set of related variables, such as the pride value of each of the characters in the story. This level of abstraction destroys one of the most useful aspects of the Erasmotron, its ability to prevent all sorts of errors on the part of the storybuilder. www.erasmatazz.com /library/Erasmatron_Design_Q2_96/Levels_of_Indirection.html   (1181 words)

Abstraction Level - TunesWiki   (Site not responding. Last check: 2007-10-03) Actually, "abstraction level" is rather a (partial) ordering over programs than an absolute qualifier for programs; abstraction is also a somewhat fuzzy concept, that can be formalized in many different ways, yielding different criteria; but the general idea is the same. An abstraction criterion can be extended to sets of programs: a set of program is more high-level than another one if for each problem solved by the second set of programs, there exist a higher-level program that solves the same problem in the first set. It can be seen that abstraction level criteria are refinements of the expressiveness criterion to compare programming languages, which itself corresponds to a trivial abstraction level criterion for programs. tunes.org /wiki/abstraction_level   (156 words)

Abstraction Abstraction is a series of one or more transformations and/or transductions connected in series (input of one device connect to the output of another device). Abstraction is composed of two processes, transformation and transduction, which may be affected by loss (generalization) or gain (particularization). Reasoning by analogy is "explained" by two abstractions, generalization and particularization; a structure is generalized to obtain a second, more abstract, structure and that more abstract structure is particularized to form the structure "analogous" to the first. www.xenodochy.org /gs/abstract.html   (2366 words)

Digital Law Online: Abstraction, Filtration, Comparison At a higher level of abstraction, the instructions in the lowest-level modules may be replaced conceptually by the functions of those modules. At progressively higher levels of abstraction, the functions of higher-level modules conceptually replace the implementations of those modules in terms of lower-level modules and instructions, until finally, one is left with nothing but the ultimate function of the program. At the abstraction level looking at the overall organization of the programs, the selection and arrangement of library routine or operating system function calls may be precisely the expression that is being considered. digital-law-online.info /lpdi1.0/treatise22.html   (3423 words)

Software Composition   (Site not responding. Last check: 2007-10-03) Abstraction is the process of hiding irrelevant detail to establish a simplified model, or the result of that process. The level of abstraction are not necessaraly hierarchical. An Event belong to a level of abstraction and can be decomposed into set of events with complex causal relation atothers level of abstraction.The duration of an event is the elapsed time between its first absolute atomic event and the last one. archive.dstc.edu.au /events/work_edc/compo2.html   (1561 words)

The Paradox of Reductionism Denying the higher levels of abstraction however, is not consistent with the new world-view; denial of the form "is nothing but" in necessitated by the need to choose only one level of abstraction, and opts for the more objective, lower level as 'reality'. The single level perspective must place multi-level terms in a context of only one level; by such choices, a level is selected as 'real', and all other levels are to be explained in terms of the selected level, all the while failing to admit of levels. Abstracting from "unmarried adult male" to "bachelor" shows that two levels are involved, and the truth of "all bachelors are bachelors" at the higher level is not the same as the truth of "all unmarried adult males are bachelors". www.xenodochy.org /philosophy/porquine.html   (3143 words)

Secrets of Great Architects (Microsoft Architect Journal)   (Site not responding. Last check: 2007-10-03) The next level of abstraction models the company's business processes for realizing the interactions that were captured at the domain level. The system level of abstraction usually requires a great deal of creativity because it is at this level that we invent ways to streamline business processes. Note that even though the classes at this level are not a proper superset of the business process classes, the architect arrives at this design by directly refining the business process classes, changing the perspective from outside the system to inside the system. msdn.microsoft.com /library/en-us/dnmaj/html/greatarchitect.asp?frame=true   (3667 words)

Level of Abstraction   (Site not responding. Last check: 2007-10-03) A central issue in any illustration algorithm is the level of abstraction. Abstraction is not just simplifying an image or eliminating detail, but focusing on specific details. Technical illustrations occupy the middle ground of abstraction, where important 3D properties of objects are accented while extraneous details are diminished or eliminated. www.cs.utah.edu /~gooch/Sig99_Amy/sld007.htm   (91 words)

Introduction to Model Driven Architecture > Raising the Level of Abstraction   (Site not responding. Last check: 2007-10-03) First, we've raised the level of abstraction of the languages we use to express behavior; second, we've sought to increase the level of reuse in system construction. As we moved from one language to another, generally we increased the level of abstraction at which the developer operates, which required the developer to learn a new, higher-level language that could then be mapped into lower-level ones, from C++ to C to assembly code to machine code and the hardware. The next level of abstraction is the move, shown in Figure 1-1, to model-based development, in which we build software-platform-independent models. www.informit.com /articles/article.asp?p=170798   (1297 words)

TDAN Becker - Perspective and Abstraction At a lower abstraction from the conceptual level resides the logical abstraction level. For example, a many-to-many relationship between two (logical level) entities “a” and “b” may be illustrated via the relational DBMS necessity of a one-to-many relationship between the tables “a” and (new, intersection) “ab” and a many-to-one relationship between tables “ab” and “b”. However, as we saw in the section on coupling perspectives with abstraction levels, it is not always clear as to what the difference between the physical abstraction level “detail” and the perspective implementation “detail” is. It may even be argued that there is little to no difference between them. www.tdan.com /i015hy02.htm   (3360 words)

Level of abstraction: Facts and details from Encyclopedia Topic   (Site not responding. Last check: 2007-10-03) (an abstraction level (or abstraction layer) is a generalization of a model or algorithm algorithm quick summary: An algorithm (the word is derived from the name of the persian mathematician al-khwarizmi), is a finite set of well-defined instructions for accomplishing some... A famous aphorism of Butler Lampson[For more facts and a topic of this subject, click this link] goes: All problems in computer science can be solved by another level of indirection; this is often deliberately mis-quoted with "abstraction" substituted for "indirection". www.absoluteastronomy.com /encyclopedia/l/le/level_of_abstraction.htm   (278 words)

Thinking Skills and Questioning I believe it is because their parents tend to think at a higher level of abstraction and the kids learn it from their parents. Parents and teachers characteristically ask questions always within a particular level, and if you can determine the levels of questions that you ask, and move to a higher level, you will be able to increase the level of abstraction and higher level thinking you are imparting to your children. If your kids are not home schooled, then they can even use this list of abstraction levels to learn the type of questions their teacher might ask (again, teachers tend to stay within the same level of abstraction!) and then use it to focus the way they study for tests with that teacher. www.alpharubicon.com /kids/kidthink.html   (961 words)

What is an Abstraction Level?   (Site not responding. Last check: 2007-10-03) The "lowest" level language is the binary language of the machine: bits moving through memory registers, processed with mindless efficiency by the CPU. At the "highest" level is the language spoken by the user (often, this is not really a "language" at all, but rather, a visual interface). A well-designed heirarchy of abstraction levels imposes no real limitations on the information which can be transmitted through its layers of translation. xaravve.trentu.ca /vato/abstr.html   (730 words)

Logic-level Simulators   (Site not responding. Last check: 2007-10-03) Logic-level simulators attempt to remedy the computationally intensive nature of circuit-level simulators by raising the level of abstraction to the domain of switches and logic components. Low level circuit devices such as transistors, capacitors and resistors are replaced with logic gates such as NAND, XOR and flip-flops. Circuits described at this level bear strong resemblance to data flow diagrams in which information is passed amongst interconnected components. www.cs.mun.ca /~donald/msc/node14.html   (332 words)

Atomicity At one level of abstraction, the operations of withdrawing, depositing, and determining your balance may each be considered atomic. At a lower level of abstraction your bank account might be represented as a file in Mellon Bank's central database. At this lower level of abstraction, we can assume that accessing and updating a file are each atomic; thus, we might effect the atomicity of the higher-level withdrawal as a sequence of lower-level atomic accesses and updates to a file. www.cs.cmu.edu /afs/cs/academic/class/15671-f95/www/handouts/concurrency/node5.html   (574 words)

Abstraction The major achievement of modern science is to demonstrate the links between phenomena at different levels of abstraction and generality, from quarks, particles, atoms and molecules right through to stars, galaxies, and (more conjecturally) the entire universe. The general technique for crossing a level of abstraction is to define the way in which an observation at one level of abstraction corresponds to one or more observations at the other level. Abstraction naturally forms views representing different ways in which the solution can be presented. www-db.stanford.edu /~burback/water_sluice/sluice6.25.97/ws/node57.html   (352 words)

ORIGIN RESEARCH But nowhere that I have discovered are these levels of abstraction defined in a systematic or formal way, defining clearly the extent to which this framework is the implicit and underlying structure for all logical processes. But as Feynman has hinted, "drawing as careful line" drawn across all levels of abstraction is a subtle challenge, and after years of working with this general intuition, I have evolved what seems to me to be the key to understanding the hierarchical organization of conceptual structure: the principles of what I call "synthetic dimensionality". The Universal Hierarchy of Abstraction is the "conceptual mainframe" for all cognition. originresearch.com /sd/sd1.cfm   (5976 words)

Classification according to the level of abstraction   (Site not responding. Last check: 2007-10-03) Abstraction allows developers to understand a problem at a higher level by hiding lower level details. Although TCP/IP sockets[22] represent the lowest level of abstraction and are the most difficult to use, they are the most flexible among all parallel programming primitives. This level of abstraction hides details of MPLs or RPCs while still keeping the underlying message passing or procedure call model visible. etude.uwaterloo.ca /~swsiu/thesis/node16.html   (722 words)

Abstraction and Efficiency In this third installment, Stroustrup discusses raising the level of abstraction, why programming is understanding, how "oops happens," and the difference between premature and prudent optimization. Abstraction is a mechanism by which we understand things. I believe raising the level of abstraction is fundamental in all practical intellectual endeavors. www.artima.com /intv/abstreffi.html   (788 words)

Harry Pierson's DevHawk Weblog : As Simple as Possible, But No Simpler So we move up a level of abstraction and use a language that humans can read more easily and that can be automatically translated (i.e. C is a higher level of abstraction than ASM, adding concepts like types and functions. Each of these levels of abstraction presents a new model of the execution environment with new features that make programming more productive (and sometimes more portable). blogs.msdn.com /devhawk/archive/2005/11/23/496381.aspx   (486 words)

Connectivity: Spike Hall's RU Weblog Summary: Communicating with a diverse audience requires you to use the least level of abstraction (words, sentence structure, paragraphs) that will effectively deliver the idea. If every layer costs you 50% of the initial audience of 100 people, by the time you reach the last one, only four people in the room have one iota of what you are talking about. To extend (and belabor?) the point; Proposition: the least abstraction necessary rule is applicable to any attempt to transmit any idea (i.e., any attempt to teach) to any audience. radio.weblogs.com /0106698/2003/03/28.html   (349 words)

Issue 2: Representation's Level of Abstraction   (Site not responding. Last check: 2007-10-03) Another aspect of the abstraction issue pertains to the level of abstraction in the symbolic representations. Marching armies and rays of radiation have their differences and similarities, and whether or not they can be used in analogical reasoning depends on the reasoner having representations of them at the same level of abstraction. Two similar ideas represented at very different levels of abstraction can lead to failures in retrieval, mapping, and transfer. www.cc.gatech.edu /~jimmyd/research/publications/cognitive-science-conference/2003/DaviesGoel2003-html/node6.html   (110 words)

Scope of Verilog   (Site not responding. Last check: 2007-10-03) Verilog can be used at different levels of abstraction as we have already seen. The RTL level of abstraction is used for functional simulation prior to synthesis. The gate level of abstraction exists post-synthesis but this level of abstraction is not often created by the designer, it is a level of abstraction adopted by the EDA tools (synthesis and timing analysis, for example). www.cse.fau.edu /~abhi/Verilog/ScopOfVer.htm   (246 words)

Chapter 2, Outline Abstraction is the purposeful suppression, or hiding, of some details of a process or artifact, in order to bring out more clearly other aspects, details, or structure. The next level of abstraction is found in some (but not all) OO languages. A critical problem in early stages of development is to determine what details are appropriate at each level of abstraction, and (often more importantly) what details should be omitted. userwww.sfsu.edu /~levine/levine/OOP-slides/ch2/ch2.html   (1138 words)

Test Driven Development vs working at the right level of abstraction   (Site not responding. Last check: 2007-10-03) In other words, what level of abstraction do I need to expose for consumers to use this module and is what I exposed working properly. TDD helps surface the realities of why a given design might suck rather than allow the suckiness to go unnoticed causing optimal design phase shifting to cascade through a codebase in such a way that can rarely be tracked to its source. TDD is indeed all about challenging design abstractions, but in doing so, it provides a path through to the application of more optimal solution designs for the given problems. weblogs.asp.net /aaguiar/archive/2005/12/05/432308.aspx   (2881 words)

Seeking Science in Art: Meta-Level Modeling This is because every data modeler has his or her own comfort level of abstraction. The important thing is to understand the pros and cons of different modeling techniques, as well as to identify the appropriate level of abstraction for the business data. The second model is the result of applying meta-level modeling to create higher level abstraction of the same business facts. www.dmreview.com /master.cfm?NavID=55&EdID=881   (3890 words)

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