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121.
Feifeng Zheng Yinfeng Xu Chung Keung Poon E. Zhang Xiaoping Wu 《Computers & Industrial Engineering》2011
This paper presents a study of the problem of online deadline scheduling under the preemption penalty model of Zheng, Xu, and Zhang (2007). In that model, each preemption incurs a penalty of ρ times the weight of the preempted job, where ρ ? 0 is the preemption penalty parameter. The objective is to maximise the total weight of jobs completed on time minus the total penalty. 相似文献
122.
As online and blended learning has become common place educational strategy in higher education, educators need to reconceptualise fundamental issues of teaching, learning and assessment in non traditional spaces. These issues include concepts such as validity and reliability of assessment in online environments in relation to serving the intended purposes, as well as understanding how formative assessment functions within online and blended learning. This article provides a systematic qualitative review of the research literature on online formative assessment in higher education. As an integrative narrative review, the method applied in this review entailed systematic searching, reviewing, and writing this review of the literature to bring together key themes and findings of research in this field. The authors applied qualitative thematic criteria in selecting and reviewing the available literature from which they focused on identifying and analyzing the core themes that are central to the concept of formative assessment with a key focus on application of formative assessment within blended and online contexts. Various techniques were identified for formative assessment by the individual, peers and the teacher, many of which were linked with online tools such as self-test quiz tools, discussion forums and e-portfolios. The benefits identified include improvement of learner engagement and centrality in the process as key actors, including the development of a learning community. The key findings are that effective online formative assessment can foster a learner and assessment centered focus through formative feedback and enhanced learner engagement with valuable learning experiences. Ongoing authentic assessment activities and interactive formative feedback were identified as important characteristics that can address threats to validity and reliability within the context of online formative assessment. 相似文献
123.
Ofir TurelAuthor Vitae 《Information & Management》2011,48(1):62-68
The use of online collaboration tools for virtual teamwork has been studied extensively, but mainly at the individual-level. We decided to examine the effect of macro-level factors (i.e., team attributes) and applied hierarchical linear modeling analysis to a sample of data collected from 96 individuals nested in 34 virtual teams. Our results suggested that the development of behavioral e-collaboration intentions by individual virtual team members was affected by their perceptions about the system, as described by individual-level IT use theories, and macro-level factors pertaining to the team. The collaboration technology was perceived to be less useful when employed to communicate with social loafers; and collective social loafing negatively influenced the teams’ potency assessments. After controlling for individual-level perceptions of system usefulness, team potency augmented team members’ intentions to use the online collaboration technology with similar teams. It also improved team performance. 相似文献
124.
Examining knowledge contribution from the perspective of an online identity in blogging communities 总被引:1,自引:0,他引:1
Knowledge contribution is one of the essential factors behind the success of blogging communities (BCs). This research studies knowledge contribution behavior in a BC from the perspective of knowledge contributors and their characteristics using the lens of social identity theory. Social identity theory asserts that individuals are fundamentally motivated to present or communicate their identities in everyday social life through behavior. A similar line of reasoning can be used to argue that members of a BC would also be motivated to communicate their online identities through their behavior, that is, through knowledge contribution in the BC. Specifically, this study conceptualized the online identity and examined the effects of its personal (online kindness, online social skills, and online creativity) and social aspects (BC involvement) on knowledge contribution. The data was collected using an online survey from the members of Cyworld, a popular BC in South Korea and a few other countries (members from South Korea were included in this study). The results indicate that both the personal and social aspects of online identity and their interactions significantly influenced knowledge contribution. Based on the findings, this study offers suggestions to organizers of BCs to enhance the knowledge contribution from their members. 相似文献
125.
Angela Fabregues Carles Sierra 《Engineering Applications of Artificial Intelligence》2011,24(7):1137-1146
There is a chronic lack of shared application domains to test advanced research models and agent negotiation architectures in Multiagent Systems. In this paper we introduce a friendly testbed for that purpose. The testbed is based on The Diplomacy Game where negotiation and the relationships between players play an essential role. The testbed profits from the existence of a large community of human players that know the game and can easily provide data for experiments. We explain the infrastructure in the paper and make it freely available to the AI community. 相似文献
126.
徐伟 《计算机应用与软件》2011,28(8)
关于磁盘阵列在线重构的研究一直以来都是国内外研究热点。提出面向数据重构算法。面向数据重构算法只对正被使用逻辑块上数据进行重构,而不需对整个磁盘进行数据重构。测试结果说明了面向数据重构算法相对于现有重构方法显著改善了磁盘阵列的重构性能。相对于DOR算法(现在最常用且最有效重构算法之一),面向数据重构算法将重构性能提高了1至2.2倍,并且没有降低重构过程中磁盘阵列服务性能。 相似文献
127.
In the frequency allocation problem, we are given a mobile telephone network, whose geographical coverage area is divided
into cells, wherein phone calls are serviced by assigning frequencies to them so that no two calls emanating from the same
or neighboring cells are assigned the same frequency. The problem is to use the frequencies efficiently, i.e., minimize the
span of frequencies used. The frequency allocation problem can be regarded as a multicoloring problem on a weighted hexagonal
graph. In this paper, we give a 1-local asymptotic 4/3-competitive distributed algorithm for multicoloring a triangle-free
hexagonal graph, which is a special case of hexagonal graph. Based on this result, we then propose a 1-local asymptotic13/9-competitive
algorithm for multicoloring the (general-case) hexagonal graph, thereby improving the previous 1-local 3/2-competitive algorithm.
A preliminary version of this paper appeared in the Proceedings of the 13th Annual International Computing and Combinatorics
Conference (COCOON 2007), LNCS 4598, pp. 526–536.
Y. Zhang research was supported by European Regional Development Fund (ERDF).
F.Y.L. Chin research was supported by Hong Kong RGC Grant HKU-7113/07E.
H. Zhu research was supported by National Natural Science Fund (grant #60496321). 相似文献
128.
We study dynamic routing in store-and-forward packet networks where each network link has bounded buffer capacity for receiving
incoming packets and is capable of transmitting a fixed number of packets per unit of time. At any moment in time, packets
are injected at various network nodes with each packet specifying its destination node. The goal is to maximize the throughput, defined as the number of packets delivered to their destinations.
In this paper, we make some progress on throughput maximization in various network topologies. Let n and m denote the number of nodes and links in the network, respectively. For line networks, we show that Nearest-to-Go (NTG), a
natural distributed greedy algorithm, is
-competitive, essentially matching a known
lower bound on the performance of any greedy algorithm. We also show that if we allow the online routing algorithm to make centralized decisions, there is a randomized
polylog(n)-competitive algorithm for line networks as well as for rooted tree networks, where each packet is destined for the root
of the tree. For grid graphs, we show that NTG has a competitive ratio of
while no greedy algorithm can achieve a ratio better than
. Finally, for arbitrary network topologies, we show that NTG is
-competitive, improving upon an earlier bound of O(mn).
An extended abstract appeared in the Proceedings of the 8th Workshop on Approximation Algorithms for Combinatorial Optimization Problems, APPROX 2005, Berkeley, CA, USA, pp. 1–13, Lecture Notes in Computer Science, vol. 1741, Springer, Berlin.
S. Angelov is supported in part by NSF Career Award CCR-0093117, NSF Award ITR 0205456 and NIGMS Award 1-P20-GM-6912-1.
S. Khanna is supported in part by an NSF Career Award CCR-0093117, NSF Award CCF-0429836, and a US-Israel Binational Science
Foundation Grant.
K. Kunal is supported in part by an NSF Career Award CCR-0093117 and NSF Award CCF-0429836. 相似文献
129.
Most studies on the role of IT for economic exchange predicted that under a given set of exchange attributes buyers would choose a certain mode of relationship with suppliers. Our study of an online IT services marketplace revealed that buyers do not have a single, uniformly preferred type of relationship, but rather maintain a portfolio of relationships. Furthermore, different buyers arrange their portfolios of exchange relationships in different ways. We found four clusters of buyers' portfolios of relationships labeled Transactional buyers, Recurrent buyers, Small diversifiers and Large diversifiers, that differ in their usage of auction or negotiation mechanism, their supplier relations as well as their usage of preferred suppliers. Our results thus paint a richer picture of how buyers organize their supplier networks online. 相似文献
130.