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22.
Maeve Paris 《Universal Access in the Information Society》2006,4(4):292-299
The provision of accessible websites is a legal requirement under the Disability Discrimination Act 1995, which applies throughout Great Britain and Northern Ireland, and the Equality (disability, etc.) (Northern Ireland) Order 2000. A survey of local e-government websites indicated that few local councils in the devolved administration of Northern Ireland offered websites which were adequately usable by people with a disability, yet most citizen-government transactions occur at the local level. Design for all has obvious commercial benefits, but it has also become a legal obligation, and application of accessible design principles should improve the online experience of all users. 相似文献
23.
24.
In this paper we summarize our recent studies of the effects of local alloy disorder on the properties ofDX levels. A single emission rate is observed in GaAs where all Si-donors have identical local environments. In contrast, three
discrete emission rates are observed in dilute AlGaAs alloys, suggesting that the group IV donor moves towards the interstitial
site, thereby “selecting” three of the twelve surrounding group III atoms. We present evidence for an ordering of theDX levels consistent with Morgan’s model of a deepening potential well for theDX level as Al atoms are subsequently substituted for Ga atoms near the relaxed donor. These conclusions are consistent with
earlier calculations of Chadi and Chang. 相似文献
25.
Ed Lowry 《Computer Standards & Interfaces》1991,13(1-3):105-108
Maximizing the satisfaction of a value in an engineering design is usually limited by tradeoffs in which other values become unacceptably sacrificed. In a few cases, however, the maximization is limited by a boundary between what is mathematically possible and what is not. Round wheels, vertical pillars, and binary memory elements are examples of optimum engineering structures which result from such mathematical limits. It is proposed that optimum characteristics of a language data model result similarly by minimizing the variety of primitive data objects, the complexity of those objects, and the number of objects needed to represent data states. Reducing these measures is needed to combine both rich data structure and powerful operations in one language. The minimizations lead to a narrow range of designs for language semantics in which the potential advantages of specialization is small compared with the advantages of commonality. Universal language for support of technical literacy appears to be an appropriate scope of generality in language design. 相似文献
26.
移动位置业务是移动通信网络的一项特色增值业务.将成为今后几年的业务增长亮点之一。中国联通总部的增值业务部于2002年采用集中设置方案,进行了CDMA位置服务系统一期工程的建设。本地定位平台建立于中国联通CDMA位置服务系统基础之上.其功能由以下的一项或多项组合而成:门户功能、中间件功能、GIS系统的的功能和对本地的CP进行管理和计费的功能。 相似文献
27.
The spatiotemporal aspects of the Portevin–Le Chatelier effect in Al–Mg alloys are investigated using direct observations of the sample surface with a digital camera. Optical measurements of the surface profile using a white light interferometer allow the estimation of the local strain and strain rate associated with the bands. The effect of Mg content on instability characteristics is analyzed. The reloading time is shown to depend on the Mg content only at the strain and strain rates where type C bands are observed. 相似文献
28.
29.
The goal of this article is to provide a construction of a homogeneous Lyapunov function
associated with a system of differential equations
, under the hypotheses: (1)
vanishes at x = 0 and is homogeneous; (2) the zero solution of this system is locally asymptotically stable. Moreover, the Lyapunov function
tends to infinity with x, and belongs to
, with
as large as wanted. As application to the theory of homogeneous systems, we present two well known results of robustness, in a slightly extended form, and with simpler proofs. 相似文献
30.