WordNet

defining a word by listing the class of entities to which the word correctly applies

PrepTutorEJDIC

(要求・命令などへの)承諾,応諾 / 服従,盲従

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/11/05 23:51:50」(JST)

wiki en

[Wiki en表示]

Look up extensibility in Wiktionary, the free dictionary.

In software engineering, extensibility (not to be confused with forward compatibility) is a system design principle where the implementation takes future growth into consideration. It is a systemic measure of the ability to extend a system and the level of effort required to implement the extension. Extensions can be through the addition of new functionality or through modification of existing functionality. The central theme is to provide for change – typically enhancements – while minimizing impact to existing system functions.

Extensibility is a software design principle defined as a system’s ability to have new functionality extended, in which the system’s internal structure and data flow are minimally or not affected, particularly that recompiling or changing the original source code is unnecessary when changing a system’s behavior, either by the creator or other programmers.^[1] Because software systems are long lived and will be modified for new features and added functionalities demanded by users, extensibility enables developers to expand or add to the software’s capabilities and facilitates systematic reuse. Some of its approaches include facilities for allowing users’ own program routines to be inserted and the abilities to define new data types as well as to define new formatting markup tags.^[2]

Extensible Design

Extensible design in software engineering is to accept that not everything can be designed in advance. Light software framework which allows for changes is provided instead. Small commands are made to prevent from losing the element of extensibility, following the principle of separating work elements into comprehensible units, in order to avoid traditional software development issues including high cohesion and low coupling and allow for continued development. Embracing change is essential to the extensible design, in which additions will be continual. Each chunk of the system will be workable with any changes, and the idea of change through addition is the center of the whole system design. Extensible design supports frequent re-prioritization and allows functionality to be implemented in small steps upon request, which are the principles advocated by the Agile methodologies and iterative development. Extensibility imposes fewer and cleaner dependencies during development, as well as reduced coupling and more cohesive abstractions, plus well defined interfaces.^[3]

Importance

Fickleness lies at the basis of all software because of human phenomenon since software is an “evolving entity” which is developed and maintained by human beings, yielding ongoing system changes in software specification and implementation.
Components of a software are often developed and deployed by unrelated parties independently. Adaptable software components are necessary since components from external vendors are unlikely to fit into a specific deployment scenario off-the-rack, taking third party users other than the manufacturer into consideration.
Many software systems and software product-lines are derived from a base system, which share a common architecture or sometimes large parts of the functionality and implementation but are possibly equipped with different components that require an extensible base system.^[4]

Classification of Extensibility Mechanisms

There are three different forms of software extensibility: white-box extensibility, gray-box extensibility, and black-box extensibility, which are based on what artifacts and the way they are changed.

White-Box Extensibility

Under this form of extensibility, a software system can be extended by modifying the source code, and it is the most flexible and the least restrictive form. There are two sub-forms of extensibility, open-box extensibility and glass-box extensibility, depending on how changes are applied.

Open-Box Extensibility

Changes are performed invasively in open-box extensible systems; i.e. original source code is directly being hacked into. It requires available source code and the modification permitted source code license. Open-box extensibility is most relevant to bug fixing, internal code refactoring, or production of next version of a software product.

Glass-Box Extensibility

Glass-box extensibility (also called architecture driven frameworks) allows a software system to be extended with available source code, but may not allow the code to be modified. Extensions have to be separated from the original system in a way that the original system is not affected. One example of this form of extensibility is object-oriented application frameworks which achieve extensibility typically by using inheritance and dynamic binding.

Black-Box Extensibility

As opposed to white-box extensibility, black-box extensibility (also called data driven frameworks) refers to the way in which no internal details about a system’s implementation or any form of source code is available for implementing deployments or extensions; only interface specification would be provided. This type of approaches is more limited than white-box approaches. Black-box extensions are typically achieved through system configuration applications or the use of application-specific scripting languages by defining components interfaces.

Gray-Box Extensibility

Gray-box extensibility is a compromise between a pure white-box and a pure black-box approach, which does not rely fully on the exposure of source code. Programmers could be given the system’s specialization interface which lists all available abstractions for refinement and specifications on how extensions should be developed.^[5]

Extensibility vs. Reusability

Extensibility and reusability have many emphasized properties in common, including low coupling, modularity and high cohesion. Software reusability is boosted by extensibility and refers to software elements’ ability to construct for many different software systems, which is motivated by the observation of software systems often sharing common elements. Reusability together with extensibility allows a technology to be transferred to another project with less development and maintenance time, as well as enhanced reliability and consistency.^[6]

References

^ Johansson, Niklas, and Anton Löfgren. Designing for Extensibility: An Action Research Study of Maximizing Extensibility by Means of Design Principles. N.p.: n.p., n.d. University of Gothenburg Department of Applied Information Technology, 29 May 2009. Web. 26 Apr. 2014. <https://gupea.ub.gu.se/bitstream/2077/20561/1/gupea_2077_20561_1.pdf>.
^ Rouse, Margaret. "Extensible." SearchSAO. N.p., Mar. 2007. Web. 27 Apr. 2014. <http://searchsoa.techtarget.com/definition/extensible>.
^ Kelly, Allan. "The Philosophy of Extensible Software." ACCU-Professionalism in Programming (2002): Web. 27 Apr. 2014. <http://accu.org/index.php/journals/391>.
^ Zenger, Matthias. "1.2 Characteristics of Extensibility Mechanisms." Programming Language Abstractions for Extensible Software Components. Lausanne: Swiss Federal Institute of Technology, 2004. N. pag. Web. 26 Apr. 2014. <http://zenger.org/papers/thesis.pdf>.
^ Zenger, Matthias. "1.3 Classiﬁcation of Extensibility Mechanisms." Programming Language Abstractions for Extensible Software Components. Lausanne: Swiss Federal Institute of Technology, 2004. N. pag. Web. 26 Apr. 2014.
^ Zenger, Matthias. "1.1.1 Reusability." Programming Language Abstractions for Extensible Software Components. Lausanne: Swiss Federal Institute of Technology, 2004. N. pag. Web. 26 Apr. 2014.

This computer programming–related article is a stub. You can help Wikipedia by expanding it.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 開腹手術における切開 incisions for open abdominal surgery
2. 慢性静脈不全に対する弾性包帯 compression bandaging for chronic venous insufficiency
3. 過剰可動性症候群の臨床症状および治療 clinical manifestations and treatment of the hypermobility syndrome
4. 陣痛のマネージメントに対する非薬理学的アプローチ nonpharmacological approaches to management of labor pain
5. 変形性関節症の非薬物療法 nonpharmacologic therapy of osteoarthritis

English Journal

Delineating the protein changes in Asian noodles induced by vacuum mixing.

Li M, Zhu KX, Peng J, Guo XN, Amza T, Peng W, Zhou HM.SourceState Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, PR China.
Food chemistry.Food Chem.2014 Jan 15;143:9-16. doi: 10.1016/j.foodchem.2013.07.086. Epub 2013 Jul 26.
In this study, the effect of vacuum mixing on Asian noodle qualities was investigated based on protein components changes and gluten formation. The results showed that the proportion of salt-soluble proteins decreased in vacuum mixed noodles while alcohol and alkali soluble proteins increased. The f
PMID 24054205

Spring-like fibers for cardiac tissue engineering.

Fleischer S, Feiner R, Shapira A, Ji J, Sui X, Daniel Wagner H, Dvir T.SourceThe Laboratory for Tissue Engineering and Regenerative Medicine, Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv 69978, Israel; Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel.
Biomaterials.Biomaterials.2013 Nov;34(34):8599-606. doi: 10.1016/j.biomaterials.2013.07.054. Epub 2013 Aug 13.
Recapitulation of the cellular microenvironment of the heart, which promotes cell contraction, remains a key challenge in cardiac tissue engineering. We report here on our work, where for the first time, a 3-dimensional (3D) spring-like fiber scaffold was fabricated, successfully mimicking the coile
PMID 23953840

Skin connective tissue and ageing.

Calleja-Agius J, Brincat M, Borg M.SourceDepartment of Obstetrics and Gynaecology, Mater Dei Hospital, Msida MSD 2090, Malta. Electronic address: jean.calleja-agius@um.edu.mt.
Best practice & research. Clinical obstetrics & gynaecology.Best Pract Res Clin Obstet Gynaecol.2013 Oct;27(5):727-40. doi: 10.1016/j.bpobgyn.2013.06.004. Epub 2013 Jul 10.
Collagen atrophy is a major factor in skin ageing. A strong correlation exists between skin collagen loss and oestrogen deficiency caused by the menopause. Skin ageing is associated with a progressive increase in extensibility and a reduction in elasticity. With increasing age, the skin also becomes
PMID 23850161

Japanese Journal

マルチドメイン構造を用いたセマンティックWeb検索対話システムの提案

小澤克貴 ,荒木雅弘
情報処理学会研究報告. SLP, 音声言語情報処理 2013-SLP-95(2), 1-6, 2013-01-25
現在開発が行われている検索対話システムの多くは,特定のタスクドメインを処理するものであるため,新たに拡張を行う際に開発者の負担が大きいという問題がある.そこで,タスクごとにドメインモジュールを作成し,モジュール間の関連性を定義することで実現する,マルチドメイン構造を用いたセマンティック Web 検索対話システムを提案する.提案手法により,追加したいタスクのモジュール化と,モジュール間の関連性の追加 …
NAID 110009526825

マルチドメイン構造を用いたセマンティックWeb検索対話システムの提案

小澤克貴 ,荒木雅弘
情報処理学会研究報告. HCI, ヒューマンコンピュータインタラクション研究会報告 2013-HCI-151(2), 1-6, 2013-01-25
現在開発が行われている検索対話システムの多くは,特定のタスクドメインを処理するものであるため,新たに拡張を行う際に開発者の負担が大きいという問題がある.そこで,タスクごとにドメインモジュールを作成し,モジュール間の関連性を定義することで実現する,マルチドメイン構造を用いたセマンティック Web 検索対話システムを提案する.提案手法により,追加したいタスクのモジュール化と,モジュール間の関連性の追加 …
NAID 110009526803

制御ソフトウェア向けテストケース生成方式の提案

磯田誠,徳永雄一
情報処理学会研究報告. ソフトウェア工学研究会報告 2012-SE-178(9), 1-8, 2012-10-25
制御システムは,制御装置を中心にセンサ装置と駆動装置を備え,外部環境に対して適切な物理的制御をかけることを目的とする.制御装置の高機能化・付加価値向上のため,制御ソフトウェアの大規模化・複雑化が進んでいる.近年,設計工程で専用記法を用いて制御ロジックを作成し,実装・試験工程で活用するモデルベース開発の取り組みが盛んである.これに対して実開発では,単体・ S/W 結合試験でのテストケースの作成工数が …
NAID 110009465426