Algebraic query optimization for distributed top-k queries     

Thomas Neumann  Sebastian Michel 《Informatik - Forschung und Entwicklung》2007,17(1):197-211

Distributed top-k query processing is increasingly becoming an essential functionality in a large number of emerging application classes. This paper addresses the efficient algebraic optimization of top-k queries in wide-area distributed data repositories where the index lists for the attribute values (or text terms) of a query are distributed across a number of data peers and the computational costs include network latency, bandwidth consumption, and local peer work. We use a dynamic programming approach to find the optimal execution plan using compact data synopses for selectivity estimation that is the basis for our cost model. The optimized query is executed in a hierarchical way involving a small and fixed number of communication phases. We have performed experiments on real web data that show the benefits of distributed top-k query optimization both in network resource consumption and query response time.  相似文献   

Agents of responsibility in software vulnerability processes     

Ari Takanen  Petri Vuorijärvi  Marko Laakso  Juha Röning 《Ethics and Information Technology》2004,6(2):93-110

Modern software is infested with flaws having information security aspects. Pervasive computing has made us and our society vulnerable. However, software developers do not fully comprehend what is at stake when faulty software is produced and flaws causing security vulnerabilites are discovered. To address this problem, the main actors involved with software vulnerability processes and the relevant roles inside these groups are identified. This categorisation is illustrated through a fictional case study, which is scrutinised in the light of ethical codes of professional software engineers and common principles of responsibility attribution. The focus of our analysis is on the acute handling of discovered vulnerabilities in software, including reporting, correcting and disclosing these vulnerabilities. We recognise a need for guidelines and mechanisms to facilitate further improvement in resolving processes leading to and in handling software vulnerabilities. In the spirit of disclosive ethics we call for further studies of the complex issues involved.  相似文献   

Short-term slackline training improves task-specific but not general balance in female handball players     

Steffen Ringhof  Nina Zeeb  Stefan Altmann  Rainer Neumann  Alexander Woll  Thorsten Stein 《European Journal of Sport Science》2019,19(5):557-566

Slackline training has been shown to improve balance and neuromuscular performance. However, recent studies suggested that balance is task-specific, implying that transferability of balance skills is limited and might depend on the similarity of the tasks. This study therefore investigated if short-term slackline training could improve performance in balance tasks that are either more or less similar to the trained slackline task. Furthermore, we assessed potential transfer effects to other neuromuscular performance tests.

25 female handball players (23.7?±?3.9 years) participated in our study and were matched to either a slackline training (SLT; n?=?14) or a control group (CON; n?=?11). The intervention comprised 12 sessions with overall 120 minutes of slackline training using single and double slacklines. Slackline standing time and measures of dynamic and static balance were assessed before and after the intervention, as well as power and sprint-related performance parameters.

Two-way repeated-measures ANOVA found a significant group?×?time interaction for slackline standing time, indicating larger training effects for SLT. For the remaining dynamic and static balance tests, no significant interactions were found. With regard to neuromuscular performance, there was a significant group?×?time interaction only in change of direction.

In essence, the study showed that slackline training induced task-specific balance improvements without affecting general balance. This adds further evidence to the task-specificity principle of balance, although the specificity of the sample as well as the briefness of the intervention should be taken into account when generalizing our findings. Nonetheless, this study contains practical implications for team sports interventions and future balance training studies, highlighting the importance of selecting appropriate balance exercises to yield rapid and the desired training outcomes.  相似文献   

Young Adults’ Trait Affection Given and Received as Functions of Hofstede’s Dimensions of Cultures and National Origin     

Daniel H. Mansson  František Marko  Katarína Bachratá  Zuzana Danišková  Jaroslava Gajdošíková Zeleiová  Vladimír Janiš 《Journal of Intercultural Communication Research》2016,45(5):404-418

Based on the work conducted by trait psychologists, this cross-cultural investigation sought to examine young adults’ trait affection given and trait affection received in the U.S., Russia, and Slovakia as functions of (a) Hofstede’s four primary dimensions of national cultures (i.e. masculinity–femininity, individualism–collectivism, uncertainty avoidance, and power distance), and (b) national origin. Undergraduate students (N = 558) from the U.S. (n = 214), Russia (n = 169), and Slovakia (n = 210) completed a questionnaire in their native languages. The results of regression analyses and analyses of variances supported the notion that the four dimensions of national cultures influence people’s trait-like attributes and therefore also result in significant differences among the three countries examined in this investigation.  相似文献   

Meinprof.de – Portal zur Ausübung des "vornehmensten Menschenrechts"?     

Sybille Neumann 《Zeitschrift für Hochschulrecht, Hochschulmanagement und Hochschulpolitik: zfhr》2009,8(5):139-148

Der nachfolgende Beitrag setzt sich mit der Frage auseinander, welche rechtlichen Grenzen für die über Internetportale erfolgende Verbreitung von Kritik an Hochschuldozenten bestehen. Dabei wird das Portal meinprof.de in den Blick genommen, auf dem Studierende ihre Dozenten und deren Veranstaltungen bewerten und kommentieren k?nnen. überprüft wird die Zul?ssigkeit der Verbreitung der Kritik und Kommentare am Ma?stab des deutschen und europ?ischen Rechts. Der Beitrag konzentriert sich zwar auf den deutschen Rechtskreis, die behandelte Frage ist wegen des Bestehens des vergleichbaren Portals meinprof.at und der Aknnüpfungen an internationales Recht aber von generellem Interesse. Die rechtliche Beurteilung solcher Plattformen h?ngt davon ab, welche Bedeutung man den Pers?nlichkeitsrechten im Verh?ltnis zur Meinungsfreiheit beimisst. Die Verfasserin pl?diert dafür, den Schutz des allgemeinen Pers?nlichkeitsrechts zu st?rken.  相似文献   

The role of students’ interests in self-regulated learning: The relationship between students’ interests, learning strategies and causal attributions     

Izabela SoriĆ  Marko PalekčiĆ 《European Journal of Psychology of Education - EJPE》2009,24(4):545-565

The purpose of this research was to examine the relationship between students’ interests, their use of certain specific learning strategies and causal attributions which they made for their academic achievement. In this manner, we attempted to explore the relationships between some important variables from three different, but connected phases of self-regulated learning: the forethought phase (interests), the performance control phase (learning strategies) and the self-reflective phase (causal attributions). Results confirmed the presumption that learning strategies could be a potential mediator in the relationship between students’ interests and their academic achievement. Also, results indicate that the causal dimension of controllability could have a partial mediating role between students’ academic achievement and their interests. Generally, our findings indicate a dynamic and cyclical nature of learning process — interest is an integral part of this process and it could be conceptualized as both a consequence and an antecedent of cognitive aspects of learning.  相似文献   

The Use of Schema Theory in Learning,Design, and Technology     

Kalianne L. Neumann  Theodore J. Kopcha 《TechTrends》2018,62(5):429-431

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Naturalization policies,education and citizenship – multicultural and multination societies in international perspectives     

Eszter Neumann 《教育政策杂志》2014,29(6):872-874

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Zentrale Abiturprüfungen als Allheilmittel?     

Marko Neumann 《Zeitschrift für Erziehungswissenschaft》2014,17(1):159-166

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Using environmental print to foster emergent literacy in children from a low-SES community     

Michelle M. Neumann 《Early childhood research quarterly》2014

Young children are exposed to environmental print within their communities and this print may be a useful resource to foster emergent literacy skills. This pre-post-test randomised controlled study examined the effects of using environmental print to enhance emergent literacy skills in children aged three to four years (N = 50) from a low-SES community in south-east Queensland, Australia. The 8-week (30 min/week) environmental print programme provided multisensory strategies for children to interact with environmental print by identifying letters and words, tracing letters with fingers, and writing letters. ANCOVAs were conducted with pre-test scores as covariates. Children in the environmental print group significantly out-performed the control group on print knowledge, sound knowledge, and print awareness skills. The programme had moderate to large effects sizes and showed that guiding low-SES preschoolers’ interactions with environmental print using multisensory strategies is an effective way to foster emergent literacy skills.  相似文献