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排序方式: 共有1112条查询结果,搜索用时 15 毫秒
1.
Markus Keidl Alfons Kemper Donald Kossmann und Alexander Kreutz 《Informatik - Forschung und Entwicklung》2002,17(3):123-134
Zusammenfassung. Wir pr?sentieren in dieser Arbeit das ObjectGlobe-System, ein offenes und verteiltes Anfragebearbeitungssystem auf Internet-Datenquellen.
ObjectGlobe erweitert die begrenzten F?higkeiten des Internets bezüglich Anfragebearbeitung, indem es einen offenen Marktplatz
schafft, in dem eine Vielzahl von Anbietern Rechenzeit, Daten und Anfrageoperatoren bereitstellen. Den Schwerpunkt dieses
Beitrags bildet die im Rahmen des ObjectGlobe-Projekts entwickelte Metadatenverwaltung MDV, ein verteiltes Metadaten-Management-System.
Es besitzt eine 3-schichtige Architektur und unterstützt Caching und Replikation in der Mittelschicht, so dass Anfragen lokal
ausgewertet werden k?nnen. Benutzer spezifizieren die Informationen, die sie ben?tigen und die repliziert werden, mit Hilfe
einer besonderen Regelsprache. Um Replikate aktuell zu halten und die Replikation von neuen und relevanten Informationen anzusto?en,
verwendet das MDV-System einen neuartigen Publish & Subscribe-Algorithmus. Wir beschreiben diesen Algorithmus im Detail und
zeigen, wie er mit Hilfe eines normalen relationalen Datenbanksystems implementiert werden kann.
Eingegangen am 19. November 2001 / Angenommen am 30. Juli 2002 相似文献
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The paper examines e-government development in Africa. This study is based on the Cape Gateway project in South Africa, a leading e-government initiative on the continent. We observe that African countries have jumped on the e-government band wagon by looking mostly at the benefits without a clear risk assessment. We argue that African countries should question the pace and pathway for their e-government programs. We caution that e-government models from developed countries do not necessarily work in Africa. E-government programs in Africa should be balanced with the provision of basic needs and infrastructure. We conclude that e-government in South Africa should adopt multi-cultural approaches, and must be underpinned by national development priorities. We recommend that the Cape Gateway must address the socio-economic context and needs of the country. The pace and pathway of its e-government must depend on the availability of both financial and human resources and also user satisfaction. 相似文献
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Ben Alexander 《Archival Science》2005,5(2-4):1-11
Despite our society's increasing reliance on electronic documentation, to-date archives remain, largely, material repositories
of cultural memory. It is an accepted historical problematic, however, that culture is often resistant to material preservation.
There exists an undeniable and profound tension between scholarly efforts to reconstruct history and interpret cultural traditions
and the fragmentary, and often limited, material record. That is to say, scholarship is shaped by a sinuous negotiation around
the historical silences that encompass all of material culture. Historical silences, however, can at times be marginalized
(or at best excluded) by a sensitive configuration of material evidence with oral history.Excluding Archival Silences: Oral History and Historical Absence uses a historically and geographically specific example of oral history to engage in a more generalist discussion of how
oral reflection, especially when shaped by material evidences, can be an especially effective tool for preserving the dynamics
of culture that often remain undocumented. 相似文献
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Key points
- Accessibility is often misunderstood as a concept that is niche or of secondary importance.
- Reframing accessibility as improving the overall user experience instantly changes the perspective; accessibility becomes a critical requirement worthy of investment and resources.
- The single most prevalent complaint amongst librarians is the time it takes to get hold of accessible content.
- An accessibility roadmap provides structure and transparency for digital accessibility projects within the organization.
- Publishers' non‐compliance with accessibility standards will increase their risk of sales declines and legal complications over time.
- The SAGE A.C.C.E.S.S.I.B.L.E mnemonic offers suggestions on how to devise a successful accessible publishing programme.
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Martin Weiss Alexandra Newman Ceri Whitmore Stephan Weiss 《European Journal of Sport Science》2016,16(4):393-401
Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records. 相似文献