Verteilte Metadatenverwaltung und Anfragebearbeitung für Internet-Datenquellen

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     

Questioning the pace and pathway of e-government development in Africa: A case study of South Africa's Cape Gateway project

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.     

Excluding archival silences: Oral history and historical absence

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.     

The secrets of failing better: Accessible publishing at SAGE. A case study

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.

     

An Empirical Investigation Demonstrating the Multidimensional DIF Paradigm: A Cognitive Explanation for DIF

Differential Item Functioning (DIF) is traditionally used to identify different item performance patterns between intact groups, most commonly involving race or sex comparisons. This study advocates expanding the utility of DIF as a step in construct validation. Rather than grouping examinees based on cultural differences, the reference and focal groups are chosen from two extremes along a distinct cognitive dimension that is hypothesized to supplement the dominant latent trait being measured. Specifically, this study investigates DIF between proficient and non-proficient fourth- and seventh-grade writers on open-ended mathematics test items that require students to communicate about mathematics. It is suggested that the occurrence of DIF in this situation actually enhances, rather than detracts from, the construct validity of the test because, according to the National Council of Teachers of Mathematics (NCTM), mathematical communication is an important component of mathematical ability, the dominant construct being assessed. However, the presence of DIF influences the validity of inferences that can be made from test scores and suggests that two scores should be reported, one for general mathematical ability and one for mathematical communication. The fact that currently only one test score is reported, a simple composite of scores on multiple-choice and open-ended items, may lead to incorrect decisions being made about examinees.     

Collaborative Development and Evaluation of an Online Nursing Course

Institutions of higher education acknowledge that online learning represents a growing segment of the modern learning environment, and most students have mastered basic computer skills. However, reluctance to engage in online learning remains among both faculty and students. This article presents a case study of three schools of nursing that collaboratively developed and implemented an online undergraduate-nursing course. The article discusses the challenges that were encountered by faculty and students. The faculty used the distance education literature to address these challenges related to technological, institutional, and pedagogical aspects of online learning, as well as the recruitment and retention of online learners. Quantitative and qualitative methods were used to evaluate the effectiveness of the course. The paper concludes with suggestions to overcome the challenges of online learning, such that faculty and students receive the inherent rewards.     

Physiotherapy Student Clinical Education: the influence of subjective judgements on observational assessment

The process of assessing students on clinical placements has to date been under‐researched. In particular, while the involvement of subjective judgements in assessing students has been discussed in the literature, there has been no attempt to look for systematic evidence. This paper comprises the first attempt to relate judgement theory to the assessment of vocational education. Preliminary results demonstrate that physiotherapy assessors made subjective judgements of their students, that these contributed to the determination of assessment grades, and that in certain cases these judgements were erroneous. The relationship of these subjective judgements to the awarding of grades via a supposedly objective assessment instrument is not yet known. Given the widespread use of such assessment instruments across different professions, the question raised is whether all observational assessment systems suffer from similar problems. If students are being judged on criteria not included on assessment instruments, perhaps the other criteria being used need to be made more explicit.     

Validating a computerized scoring system for assessing writing and placing students in composition courses

How do scores from writing samples generated by computerized essay scorers compare to those generated by “untrained” human scorers and what combination of scores, if any, is more accurate at placing students in composition courses? This study endeavored to answer this two-part question by evaluating the correspondence between writing sample scores generated by the IntelliMetric™ automated scoring system and scores generated by University Preparation English faculty, as well as examining the predictive validity of both the automated and human scores. The results revealed significant correlations between the faculty scores and the IntelliMetric™ scores of the ACCUPLACER™ OnLine WritePlacer Plus test. Moreover, logistic regression models that utilized the IntelliMetric™ scores and average faculty scores were more accurate at placing students (77% overall correct placement rate) than were models incorporating only the average faculty score or the IntelliMetric™ scores.