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231.
Collaborative filtering aims at predicting a test user’s ratings for new items by integrating other like-minded users’ rating information. The key assumption is that users sharing the same ratings on past items tend to agree on new items. Traditional collaborative filtering methods can mainly be divided into two classes: memory-based and model-based. The memory-based approaches generally suffer from two fundamental problems: sparsity and scalability, and the model-based approaches usually cost too much on establishing a model and have many parameters to be tuned. 相似文献
232.
A new design method based on artificial bee colony algorithm for digital IIR filters 总被引：11，自引：0，他引：11
Nurhan Karaboga Author Vitae 《Journal of The Franklin Institute》2009,346(4):328-348
Digital filters can be broadly classified into two groups: recursive (infinite impulse response (IIR)) and non-recursive (finite impulse response (FIR)). An IIR filter can provide a much better performance than the FIR filter having the same number of coefficients. However, IIR filters might have a multi-modal error surface. Therefore, a reliable design method proposed for IIR filters must be based on a global search procedure. Artificial bee colony (ABC) algorithm has been recently introduced for global optimization. The ABC algorithm simulating the intelligent foraging behaviour of honey bee swarm is a simple, robust, and very flexible algorithm. In this work, a new method based on ABC algorithm for designing digital IIR filters is described and its performance is compared with that of a conventional optimization algorithm (LSQ-nonlin) and particle swarm optimization (PSO) algorithm. 相似文献
233.
Multidisciplinary teams are an essential aspect of modern organizational work. These teams often work in information-rich environments but little is known about their collaborative information seeking (CIS) behavior. We have been studying the CIS behavior of teams in the context of medical care. We conducted an ethnographic field study of a multidisciplinary patient care team in an emergency department to identify (a) team information needs and (b) situations that trigger collaborative information seeking activities. We identified seven categories of information needs as expressed by questions asked by team members. The majority of questions focused on medical information, but there were a larger than expected percentage of questions focusing on organizational information. We also identified three triggers for CIS activities. These triggers are: (1) lack of expertise, (2) lack of immediately accessible information, and (3) complex information needs. The questions and triggers highlight the importance of face-to-face communication during CIS activities and how CIS activities could lead to interruptive workplaces. We also discuss organizational and technical implications for supporting CIS behavior of teams. 相似文献
234.
Mahmoud Rokaya Elsayed Atlam Masao FuketaAuthor VitaeTshering C. DorjiAuthor Vitae Jun-ichi AoeAuthor Vitae 《Information processing & management》2008
Information retrieval involves finding some desired information in a store of information or a database. In this paper, Co-word analysis will be used to achieve a ranking of a selected sample of FA terms. Based on this ranking a better arranging of search results can be achieved. Experimental results achieved using 41 MB of data (7660 documents) in the field of sports. The corpus was collected from CNN newspaper, sports field. This corpus was chosen to be distributed over 11 sub-fields of the field sports from the experimental results, the average precision increased by 18.3% after applying the proposed arranging scheme depending on the absolute frequency to count the terms weights, and the average precision increased by 17.2% after applying the proposed arranging scheme depending on a formula based on “TF∗IDF” to count the terms weights. 相似文献
235.
Matthew Jarron Author Vitae 《Museum Management and Curatorship》2006,21(2):88-94
One of the first things Patrick Geddes did on taking up the post of Professor of Botany at University College, Dundee was to establish a botanical museum. Throughout his life museums were of great importance to him, and were central to his theories as an educationalist. The Outlook Tower in Edinburgh was the most famous demonstration of these theories, but this short introductory paper also looks at less well known aspects of them, such as his ground-breaking paper to the Museums Association conference in Dundee in 1907, his unpublished book.
Museums
Actual and Possible, and his attempts to win the directorship of the Edinburgh Museum of Science and Art. 相似文献236.
美国《科学》杂志是在国际学术界有着很大影响、很高地位的权威性杂志,在国际及国内都拥有广大的读者群.该杂志电子版中国服务器已经于1998年初在北京大学正式开通,使国内读者能以最经济、最快速、最便捷的方式进行阅览.其网址是:http://China.Sciencemag.org.目前,该网址中收录了自1995年10月6日以来所有各期的文章全文.本文简要介绍美国《科学》杂志在Internet上的阅览办法.在其主页当中,点击"Science"后面的相应选项,即可分别进行如下检索、阅览. 相似文献
237.
Hongwu Sam Ouyang Author Vitae 《Research Policy》2006,35(9):1314-1328
Taiwan has made significant progress in the semiconductor industry with government agencies and bureaucrats as the driving forces over the past 30 years. Taiwan's impressive achievement in the semiconductor industry clearly indicates that the government failures and agency problem usually associated with deep government involvement did not occur in Taiwan. Why is that the case? This paper proposes a principal-agent framework for technology policy and applies the framework to discuss the institutional arrangements through which bureaucrats were controlled effectively in executing the semiconductor industry policies in Taiwan. By analyzing the institutional and organizational arrangements Taiwanese leaders made to mitigate the agency problem, this paper brings bureaucrats into the popular developmental state theory and emphasizes that the success of state intervention should not be taken for granted, and it also brings politics into technology policy analysis and stresses the importance and complexity of agency problem in technology policy. 相似文献
238.
Gino SegréAuthor Vitae 《Journal of The Franklin Institute》2002,339(3):303-305
The Franklin Institute, Philadelphia, Pennsylvania, awarded the 2001 Benjamin Franklin Medal in Physics to Alan H. Guth for his efforts to advance our knowledge of physical science and its application of the inflationary scenario, in which the universe undergoes a rapid expansion in the first stages of the Big Bang. 相似文献
239.
Giuseppe Grassi Author Vitae 《Journal of The Franklin Institute》2010,347(2):438-451
Projective synchronization is a type of chaos synchronization where the response system states are scaled replicas of the drive system states. This paper deals with the propagation of projective synchronization in a series connection of N chaotic discrete-time drive systems and N response systems. By exploiting an observer-based approach, the paper demonstrates that dead-beat projective synchronization (i.e., exact synchronization in finite time for any scaling factor) is achieved between the nth drive and nth response systems. In particular, it is shown that projective synchronization starts from the innermost (Nth) drive-response system pair and propagates toward the outermost (first) drive-response system pair. Only a single scalar synchronizing signal connects the cascaded drive and response systems. Finally, an example illustrates the propagation of different types of chaos synchronization in a series connection consisting of a Gingerbreadman map, a third order hyperchaotic Henon map and a Lozi map. 相似文献
240.
William F. Michne Author Vitae 《Journal of The Franklin Institute》2010,347(4):664-671
Organic synthesis of natural products began in 1828 with Wohler's synthesis of urea, the first time a substance derived from a living organism had been produced by combining inorganic materials. Progress in the field was slow at first, due to the limited purification and analytical methods. Advances in those areas gave rise to rapid progress in synthesis, as chemists could now focus their energies on devising new approaches to the preparation of increasingly complex molecules. While it is possible to prepare many molecules by using known chemistry in new combinations, real progress has been the result of keen insight and creativity on the part of only a few individuals.Professor Samuel J. Danishefsky established himself early on as a leader in this field when he recognized that a well-known ring forming reaction could be greatly extended by adding chemical functionality to one of the components. He then found that these new reactive components could react with heretofore unreactive components to produce new rings containing oxygen atoms both in the ring and as attachments to the ring. These products were very similar to naturally occurring sugars. Danishefsky realized that he could develop this chemistry further to produce precisely defined polysaccharides as well. Some of these polysaccharides occur on the surface of cancer cells. Using the chemistry he developed, he was able to prepare these cancer cell markers, and after combining them with certain proteins, showed that the resulting molecules behaved as cancer vaccines. Several have entered clinical trial.Danishefsky has synthesized many other natural products, but he is particularly interested in those that may be useful in treating cancer. His syntheses allow for the modification of the final product in ways that improve both safety and efficacy. Several of these compounds have also entered clinical trials. Thus his work has not only advanced the art and science of organic synthesis, but stands to make dramatic advances in the treatment of cancer as well. 相似文献