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Application scheduling plays an important role in high-performance cluster computing. Application scheduling can be classified as job scheduling and task scheduling. This paper presents a survey on the software tools for the graph-based scheduling on cluster systems with the focus on task scheduling. The tasks of a parallel or distributed application can be properly scheduled onto multi-processors in order to optimize the performance of the program (e.g., execution time or resource utilization). In general, scheduling algorithms are designed based on the notion of task graph that represents the relationship of parallel tasks. The scheduling algorithms map the nodes of a graph to the processors in order to minimize overall execution time. Although many scheduling algorithms have been proposed in the literature, surprisingly not many practical tools can be found in practical use. After discussing the fundamental scheduling techniques, we propose a framework and taxonomy for the scheduling tools on clusters. Using this framework, the features of existing scheduling tools are analyzed and compared. We also discuss the important issues in improving the usability of the scheduling tools. This work is supported by the Hong Kong Polytechnic University under grant H-ZJ80 and by NASA Ames Research Center by a cooperative grant agreement with the University of Texas at Arlington. Jiannong Cao received the BSc degree in computer science from Nanjing University, Nanjing, China in 1982, and the MSc and the Ph.D degrees in computer science from Washington State University, Pullman, WA, USA, in 1986 and 1990 respectively. He is currently an associate professor in Department of Computing at the Hong Kong Polytechnic University, Hong Kong. He is also the director of the Internet and Mobile Computing Lab in the department. He was on the faculty of computer science at James Cook University and University of Adelaide in Australia, and City University of Hong Kong. His research interests include parallel and distributed computing, networking, mobile computing, fault tolerance, and distributed software architecture and tools. He has published over 120 technical papers in the above areas. He has served as a member of editorial boards of several international journals, a reviewer for international journals/conference proceedings, and also as an organizing/programme committee member for many international conferences. Dr. Cao is a member of the IEEE Computer Society, the IEEE Communication Society, IEEE, and ACM. He is also a member of the IEEE Technical Committee on Distributed Processing, IEEE Technical Committee on Parallel Processing, IEEE Technical Committee on Fault Tolerant Computing, and Computer Architecture Professional Committee of the China Computer Federation. Alvin Chan is currently an assistant professor at the Hong Kong Polytechnic University. He graduated from the University of New South Wales with a Ph.D. degree in 1995 and was subsequently employed as a Research Scientist by the CSIRO, Australia. From 1997 to 1998, he was employed by the Centre for Wireless Communications, National University of Singapore as a Program Manager. Dr. Chan is one of the founding members and director of a university spin-off company, Information Access Technology Limited. He is an active consultant and has been providing consultancy services to both local and overseas companies. His research interests include mobile computing, context-aware computing and smart card applications. Yudong Sun received the B.S. and M.S. degrees from Shanghai Jiao Tong University, China. He received Ph.D. degree from the University of Hong Kong in 2002, all in computer science. From 1988 to 1996, he was among the teaching staff in Department of Computer Science and Engineering at Shanghai Jiao Tong University. From 2002 to 2003, he held a research position at the Hong Kong Polytechnic University. At present, he is a Research Associate in School of Computing Science at University of Newcastle upon Tyne, UK. His research interests include parallel and distributed computing, Web services, Grid computing, and bioinformatics. Sajal K. Das is currently a Professor of Computer Science and Engineering and the Founding Director of the Center for Research in Wireless Mobility and Networking (CReWMaN) at the University of Texas at Arlington. His current research interests include resource and mobility management in wireless networks, mobile and pervasive computing, sensor networks, mobile internet, parallel processing, and grid computing. He has published over 250 research papers, and holds four US patents in wireless mobile networks. He received the Best Paper Awards in ACM MobiCom’99, ICOIN-16, ACM, MSWiM’00 and ACM/IEEE PADS’97. Dr. Das serves on the Editorial Boards of IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks, Parallel Processing Letters, Journal of Parallel Algorithms and Applications. He served as General Chair of IEEE PerCom’04, IWDC’04, MASCOTS’02 ACM WoWMoM’00-02; General Vice Chair of IEEE PerCom’03, ACM MobiCom’00 and IEEE HiPC’00-01; Program Chair of IWDC’02, WoWMoM’98-99; TPC Vice Chair of ICPADS’02; and as TPC member of numerous IEEE and ACM conferences. Minyi Guo received his Ph.D. degree in information science from University of Tsukuba, Japan in 1998. From 1998 to 2000, Dr. Guo had been a research scientist of NEC Soft, Ltd. Japan. He is currently a professor at the Department of Computer Software, The University of Aizu, Japan. From 2001 to 2003, he was a visiting professor of Georgia State University, USA, Hong Kong Polytechnic University, Hong Kong. Dr. Guo has served as general chair, program committee or organizing committee chair for many international conferences, and delivered more than 20 invited talks in USA, Australia, China, and Japan. He is the editor-in-chief of the Journal of Embedded Systems. He is also in editorial board of International Journal of High Performance Computing and Networking, Journal of Embedded Computing, Journal of Parallel and Distributed Scientific and Engineering Computing, and International Journal of Computer and Applications. Dr. Guo’s research interests include parallel and distributed processing, parallelizing compilers, data parallel languages, data mining, molecular computing and software engineering. He is a member of the ACM, IEEE, IEEE Computer Society, and IEICE. He is listed in Marquis Who’s Who in Science and Engineering.  相似文献   

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To deal with the environment’s heterogeneity, information providers usually offer access to their data by publishing Web services in the domain of pervasive computing. Therefore, to support applications that need to combine data from a diverse range of sources, pervasive computing requires a middleware to query multiple Web services. There exist works that have been investigating on generating optimal query plans. We however in this paper propose a query execution model, called PQModel, to optimize the process of query execution over Web Services. In other words, we attempt to improve query efficiency from the aspect of optimizing the execution processing of query plans.  相似文献   

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Conflicts between the conservation of biodiversity and other human activities occur in all habitats and can impact severely upon socio-economic and biological parameters. In a changing environment, with increasing pressure on ecosystem goods and services and increasing urgency for biodiversity conservation, these conflicts are likely to increase in importance and magnitude and negatively affect biodiversity and human well-being. It is essential, however, to better understand what is meant by ‘biodiversity conflicts’ in order to develop ways to manage these effectively. In view of the complexity of the social and ecological contexts of conflicts, this paper explores ‘biodiversity impacts’ linked to agricultural, forestry and other sectoral activities in the UK. The paper then describes the transition from ‘biodiversity impacts’ to ‘biodiversity conflicts’, illustrating this concept with specific examples. While generalisations relating to conflict management are made difficult by their unique contextual settings, this paper suggests approaches for their management, based on the experiences of scientists who have been involved in managing conflicts. We consider the role of science and scientists; trust and dialogue; and temporal and spatial scales in biodiversity conflicts and highlight the combined role they play in successful biodiversity conflict management. Recommendations are also made for future research on biodiversity conflicts in a changing environment.  相似文献   

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Rivers, lakes and wetlands are good examples of ecosystems that provide multiple, concurrent, services to mankind. Human society has often exploited these systems by enhancing one ecosystem service at the expense of another. Loch Leven, Scotland, UK, is a good example of this. Over the past 150 years, the lake has been subjected to hydrological modification, fish stocking and pollution control to improve the delivery of key goods and services. This study uses historical records to explore the results of these interventions on the ecosystem services that were targeted for improvement and the knock-on effects on other services provided by the lake. The results suggest that, when management changes are being considered to enhance particular ecosystem services, the potentially damaging effects on other ecosystem services should be taken into account. This requires a better understanding of the role of ecosystem function in delivering ecosystem services, and of the links between multiple ecosystem services, than is currently available. While further research is clearly needed, the value of long-term datasets in providing knowledge and understanding through ‘hindsight’ should not be underestimated. The study concludes that successful management actions are likely to be those that incorporate lessons learned from previous decisions.  相似文献   

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In 1919 the Animal Breeding Research Department was established in Edinburgh. This Department, later renamed the Institute of Animal Genetics, forged an international reputation, eventually becoming the centrepiece of a cluster of new genetics research units and institutions in Edinburgh after the Second World War. Yet despite its significance for institutionalising animal genetics research in the UK, the origins and development of the Department have not received as much scholarly attention as its importance warrants. This paper sheds new light on Edinburgh’s place in early British genetics by drawing upon recently catalogued archival sources including the papers of James Cossar Ewart, Regius Professor of Natural History at the University of Edinburgh between 1882 and 1927. Although presently a marginal figure in genetics historiography, Ewart established two sites for experimental animal breeding work between 1895 and 1911 and played a central role in the founding of Britain’s first genetics lectureship, also in 1911. These early efforts helped to secure government funding in 1913. However, a combination of the First World War, bureaucratic problems and Ewart’s personal ambitions delayed the creation of the Department and the appointment of its director by another six years. This paper charts the institutionalisation of animal breeding and genetics research in Edinburgh within the wider contexts of British genetics and agriculture in the early twentieth century.  相似文献   

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Biodiversity conservation organisations have recently begun to consider a wider ecosystem services context for their activities. While the literature suggests the potential of ‘win–win’ situations where biodiversity conservation and the delivery of ecosystem services overlap, empirical evidence is wanting. Here we explore the role that species-led management for the benefit of biodiversity in cultural landscapes can play in the delivery of wider ecosystem services. We use UK lowland wetlands as a case study and show how successful delivery of species-led conservation through management interventions relies on practices that can affect greenhouse gas fluxes, water quality and regulation, and cultural benefits. In these wetlands, livestock grazing has potentially large effects on water and greenhouse gas related services, but there is little scope to alter management without compromising species objectives. Likewise, there is little potential to alter reedbed management without compromising conservation objectives. There is some potential to alter woodland and scrub management, but this would likely have limited influence due to the relatively small area over which such management is practiced. The management of water levels potentially has large effects on provision of several services and there does appear to be some scope to align this objective with biodiversity objectives. A comprehensive understanding of the net costs and benefits to society of these interventions will require fine-grained research integrating ecological, economic and social science research. However, a less analytic understanding of the potential costs and benefits can highlight ways by which land management principally to achieve biodiversity conservation objectives might be modified to enhance delivery of other ecosystem services.  相似文献   

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This paper argues that the history of the computer, of the practice of computation and of the notions of 'data' and 'programme' are essential for a critical account of the emergence and implications of data-driven research. In order to show this, I focus on the transition that the investigations on the worm C. elegans experienced in the Laboratory of Molecular Biology of Cambridge (UK). Throughout the 1980s, this research programme evolved from a study of the genetic basis of the worm's development and behaviour to a DNA mapping and sequencing initiative. By examining the changing computing technologies which were used at the Laboratory, I demonstrate that by the time of this transition researchers shifted from modelling the worm's genetic programme on a mainframe apparatus to writing minicomputer programs aimed at providing map and sequence data which was then circulated to other groups working on the genetics of C. elegans. The shift in the worm research should thus not be simply explained in the application of computers which transformed the project from hypothesis-driven to a data-intensive endeavour. The key factor was rather a historically specific technology-in-house and easy programmable minicomputers-which redefined the way of achieving the project's long-standing goal, leading the genetic programme to co-evolve with the practices of data production and distribution.  相似文献   

9.
Social Hymenoptera have been relatively little studied in terms of conservation genetics even though their sociality and complementary sex determination potentially influence the interaction of genetics with extinction risk. Using microsatellite markers, we investigated the social and genetic structure of nests and populations of the Black Bog Ant Formica picea at four sites in the UK, where this habitat specialist has a localized and fragmented range. Nests were weakly polygynous (effective queen number, 4–27 per nest) with low worker relatedness. Isolation by distance tended to be present within sites, indicating limited dispersal, but inbreeding was rare. The four study sites fell into three main populations (two in South Wales, one in southern England). We conclude that, although UK F. picea populations are not at immediate risk from genetic factors, their limited dispersal abilities at both within- and between-site scales should inform conservation management decisions.  相似文献   

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Increasing scientific and commercial interest is being paid to the creation of large population-based genetic databases to study the relationship between genes and disease. This paper will use ideas from the sociology of technology to look at the network of actors involved in the production, use and commercial exploitation of human genetic data, the social and ethical issues posed by genetic databases and the development of new governance arrangements in this domain. It will be argued that we are witnessing the creation of a new type of research system in the field of human genetics, which also forms the centre of an emerging market for personal and population-based genetic information. Some proposals for improving the governance of human genetic data in the UK will be offered in conclusion.  相似文献   

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Michurinist biology was introduced to China in 1948; granted a state supported monopoly in 1952; and reduced to parity with western genetics from 1956. The Soviets exported it through the propaganda agencies Sino Soviet Friendship Association (SSFA) and VOKS (Cultural Relations with Foreign Countries). China’s Ministry of Agriculture achieved broad public awareness and acceptance of Michurinist biology through a translation, publication, and Soviet guest speakers campaign – all managed by a team of agriculturalists led by Luo Tianyu, a veteran CCP (Communist Party) cadre. The campaign grew exponentially, but did not affect university or Chinese Academy of Sciences biology. Luo Tianyu’s failed attempt to force Michurinist biology on a Beijing university triggered its second stage: monopoly status and a ban on “Mendelist-Morganist” biology in teaching, research, and publication. The CCP Central Committee supported this policy believing that Michurinst biology would increase agricultural production for the forthcoming first Five Year Plan; whereas, western genetics had no practical value. Michurinist biology flourished at all levels of education, research, and science literature; Western genetics was completely shut down. This only began to change when the CCP Central Committee became wary of China’s dependency on Soviet technical expertise and failure to fully utilize that of China. Change was further promoted by significant attacks on Michurinist biology by Soviet and East German biologists. Soon, these developments informed China’s “genetics question,” which became a test case for larger questions about the definition of science and the relationship between scientists and the state. Under the guidance of Lu Dingyi’s Central Committee Propaganda Department, the CCP eventually decided that, henceforth, science controversies would only be resolved by the science community; and that monopolies or ideological orthodoxies would not be imposed on science. At the same time, the CCP rescinded Michurinist biology’s monopoly and the ban on western genetics. By the mid-1960s western genetics had successfully restored itself, largely due to the leadership of C. C. Tan, a former student of Dobzhansky. Michurinist biology’s presence shrank and it became marginalized.  相似文献   

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This paper examines the history of Japanese genetics in the 1920s to 1950s as seen through the work of Hitoshi Kihara, a prominent wheat geneticist as well as a leader in the development of the discipline in Japan. As Kihara’s career illustrates, Japanese genetics developed quickly in the early twentieth century through interactions with biologists outside Japan. The interactions, however, ceased due to the war in the late 1930s, and Japanese geneticists were mostly isolated from outside information until the late 1940s. During the isolation in wartime and under the postwar U.S. Occupation, Kihara adapted to political changes. During wartime, he developed a research institute focusing on applied biology of various crops, which conformed to the national need to address food scarcity. After the war, he led the campaign for the establishment of a national institute of genetics and negotiated with American Occupation officers. The Americans viewed this Japanese effort with suspicion because of the rising popularity of the controversial theory of the Russian agronomist, Trofim Lysenko, in Japan. The institute was approved in 1949 partly because Kihara was able to bridge the gap between the American and Japanese sides. With Kihara’s flexible and generous leadership, Japanese genetics steadily developed, survived the wartime, and recovered quickly in the postwar period. The article discusses Kihara’s interest in cytoplasmic inheritance and his synthetic approach to genetics in this political context, and draws attention to the relation between Kihara’s genetics and agricultural practice in Japan.  相似文献   

13.
This paper provides a brief comparative overview of the development of the reproductive sciences especially in agriculture in the UK and the US. It begins with the establishment by F. H. A. Marshall in 1910 of the boundaries that framed the reproductive sciences as distinct from genetics and embryology. It then examines how and where the reproductive sciences were taken up in agricultural research settings, focusing on the differential development of US and UK institutions. The reproductive sciences were also pursued in medical and biological settings, and I discuss how the intersections among all three allowed the circulation of both ideas and scientists' careers. Across the twentieth century, scientific leadership in the reproductive sciences alternated between the UK and US, and these patterns are elucidated. I conclude with thoughts on future research that might emphasize the elaboration of industrialization processes in agriculture and new capacities to transform both reproductive processes and their products--life itself--as biopower comes to be more ambitiously understood as extending across all species.  相似文献   

14.
Pediatric genetics is growing in significance as a tool to explain childhood illness and disability. Within both medical sociology and anthropology writers have explored whether investigating genetic inheritance can overemphasize biological connection over other versions of kinship and can also lead to new forms of responsibility being imposed on parents for being “guilty” of sharing problematic “substance” with their offspring. Such considerations are complicated by the fact that a child's genetic variation is not necessarily something they inherited from their parents. This paper explores how questions of inheritance and responsibility are brought into play by pediatric genetics. It does so by drawing on ethnographic research of a genetics service in the UK. In particular we highlight how understandings of kinship can be unsettled by genetic scrutiny, but that once unsettled are not resolved by establishing whether a child has or has not inherited a genetic condition from their parents. Instead existing cultural kinship understandings of the moral substance of kinship responsibility towards producing and raising the right kinds of children are of equal (if not more) importance.  相似文献   

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The Linux cluster considered in this paper, formed from shuttle box XPC nodes with 2 GHz Athlon processors connected by dual Gb Ethernet switches, is relatively easily constructed, but, while effective as a throughput engine, may result in disappointing results when running explicitly parallel software if weakly-performing communication mechanisms and process spawning are selected. This paper carefully compares the implementations of communication and spawning primitives in MPICH-2, openMosix, and Linux Remote Procedure Call, forking, and various lower-level communication mechanisms. The test selection compares the provision of both a message-passing library, and a single system image software package, with direct use of lower-level primitives. The information in the paper will be of interest to those considering the use of one of the well-known packages, or directly writing their own distributed applications, or constructing a distributed language by layering on top of an existing set of parallel primitives. The results expose a ranking in terms of process spawning and a similar ranking of communication software performance. They reveal poor performance in certain circumstances, well below the hardware specification, which it is as well that the developer is aware of. In general, the paper emphasizes the importance of efficient transport software to cluster machines. David J. Johnston has worked as software engineer in research and development for 20 years, at ICL Ltd. and the Rutherford-Appleton Laboratory, UK. His strengths lie in generating and realizing algorithms for complex systems. His interests include languages and methodologies to shorten the software development process. He has recently completed a Ph.D. at the University of Essex, UK in position identification for augmented reality. He has co-authored a book on Computer Graphics. Martin Fleury is a Senior Lecturer at the University of Essex, UK, where he was also awarded a Ph.D. in Parallel Image Processing. His first degree was from Oxford University, and he holds an MSc in Astrophysics from the University of London. He is the principal author of a book on parallel computing for embedded systems. He has authored thirty-five journal papers in the last ten years on parallel image and vision processing, performance prediction, real-time systems, reconfigurable computing, software engineering, and video and document compression. Michael Lincoln has completed an M.Sc. and Ph.D. at the University of Essex, UK in the field of face recognition and face tracking. His work as a Senior Research Officer is concerned with radar control of aircraft landings. The cluster mentioned in the paper was constructed, configured, and commissioned by Michael. Andrew C. Downton was educated at Southampton University, UK, where he obtained a first class honours degree in Electronic Engineering in 1974, and a Ph.D. in 1982, and where he was also a lecturer. In 1995 he was promoted to a personal Chair at the University of Essex, UK, and in 1999 he became Head of the Department of Electronic Systems Engineering at Essex. His research interests include pattern recognition and image analysis; parallel computer architectures; hardware-software co-design; handwriting recognition; and document analysis. He is a Chartered Engineer and Fellow of the Institution of Electrical Engineers (IEE) and a Senior Member of the IEEE.  相似文献   

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As computing technology becomes more pervasive and mobile services are deployed, applications will need flexible access control mechanisms. Although lots of researches have been done on access control, these efforts focus on relatively static scenarios where access depends on identity of the subject. They do not address access control issues for pervasive applications where the access privileges of a subject not only depend on its identity but also on its current context and state. In this paper, we present the SESAME dynamic context-aware access control mechanism for pervasive applications. SESAME complements current authorization mechanisms to dynamically grant and adapt permissions to users based on their current context. The underlying dynamic role based access control (DRBAC) model extends the classic role based access control (RBAC). We also present a prototype implementation of SESAME and DRBAC with the Discover computational collaboratory and an experimental evaluation of its overheads. Guangsen Zhang is Ph.D. student in the Department of Electrical and Computer Engineering at Rutgers University. He received his MS from Rutgers University. His research interests include parallel & distributed computing, distributed system security. Manish Parashar is an Associate Professor in the Department of Electrical and Computer Engineering at Rutgers University. His research interests include autonomic computing, parallel & distributed computing, scientific computing, and software engineering.  相似文献   

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Those clinical genetic services that do not involve laboratory tests or procedures--i.e., the "cognitive" services such as diagnosis, management, and counseling--are labor-intensive, time-consuming, and not self-supporting. However, as a result of an evaluation at a genetics clinics, a patient will often receive other services at the same medical center. The full economic impact of the genetics clinic may be underappreciated. Therefore, at one medical center we examined (a) three settings that delivered genetics services and (b) two specialty clinics providing services to children with genetics conditions; and we calculated charges and payments for an unselected, consecutive group of outpatients. The results showed that cognitive genetics services accounted for a variable, but generally low, percentage of both the professional (generally physicians') and total charges accumulated by patients as a consequence of their visit to the genetics clinic. With laboratory and procedural charges included, patients seen in general genetics clinics (or their insurance plans) paid up to three times as much to the medical center and to its health professionals as to the genetics professional. These data confirm that clinical genetics services, while not generating enough income to cover their own costs, bring considerable revenue to the medical center. This fact alone should prove useful to the director of clinical genetics programs when they are negotiating finances with institutional administrators.  相似文献   

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New ‘omics’ technologies are changing nutritional sciences research. They enable to tackle increasingly complex questions but also increase the need for collaboration between research groups. An important challenge for successful collaboration is the management and structured exchange of information that accompanies data-intense technologies. NuGO, the European Nutrigenomics Organization, the major collaborating network in molecular nutritional sciences, is supporting the application of modern information technologies in this area. We have developed and implemented a concept for data management and computing infrastructure that supports collaboration between nutrigenomics researchers. The system fills the gap between “private” storing with occasional file sharing by email and the use of centralized databases. It provides flexible tools to share data, also during experiments, while preserving ownership. The NuGO Information Network is a decentral, distributed system for data exchange based on standard web technology. Secure access to data, maintained by the individual researcher, is enabled by web services based on the the BioMoby framework. A central directory provides information about available web services. The flexibility of the infrastructure allows a wide variety of services for data processing and integration by combining several web services, including public services. Therefore, this integrated information system is suited for other research collaborations.  相似文献   

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An increasing number of personal electronic handheld devices (e.g., SmartPhone, netbook, MID and etc.), which make up the personal pervasive computing environments, are playing an important role in our daily lives. Data storage and sharing is difficult for these devices due to the data inflation and the natural limitations of mobile devices, such as the limited storage space and the limited computing capability. Since the emerging cloud storage solutions can provide reliable and unlimited storage, they satisfy to the requirement of pervasive computing very well. Thus we designed a new cloud storage platform which includes a series of shadow storage services to address these new data management challenges in pervasive computing environments, which called as “SmartBox”. In SmartBox, each device is associated its shadow storage with a unique account, and the shadow storage acts as backup center as well as personal repository when the device is connected. To facilitate file navigation, all datasets in shadow storage are organized based on file attributes which support the users to seek files by semantic queries. We implemented a prototype of SmartBox focusing on pervasive environments being made up of Internet accessible devices. Experimental results with the deployments confirm the efficacy of shadow storage services in SmartBox.  相似文献   

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