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A comparison of six approaches to discretization-a rough set perspective

3rd International Conference on Rough Sets and Knowledge Technology, RSKT 2008

作者： Blajdo, Piotr Grzymala-Busse, Jerzy W. Hippe, Zdzislaw S. Knap, Maksymilian Mroczek, Teresa Piatek, Lukasz Department of Expert Systems and Artificial Intelligence University of Information Technology and Management Rzeszow 35-225 Poland Department of Electrical Engineering and Computer Science University of Kansas Lawrence KS 66045 United States Department of Distributed Systems University of Information Technology and Management Rzeszow 35-225 Poland Institute of Computer Science Polish Academy of Sciences Warsaw 01-237 Poland

ISBN: (纸本)3540797203

We present results of extensive experiments performed on nine data sets with numerical attributes using six promising discretization methods. For every method and every data set 30 experiments of ten-fold cross validation were conducted and then means and sample standard deviations were computed. Our results show that for a specific data set it is essential to choose an appropriate discretization method since performance of discretization methods differ significantly. However, in general, among all of these discretization methods there is no statistically significant worst or best method. Thus, in practice, for a given data set the best discretization method should be selected individually. © 2008 Springer-Verlag Berlin Heidelberg.

关键词： Rough set theory

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How well does JXTA fit Peer-to-Peer SIP?

How well does JXTA fit Peer-to-Peer SIP?

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Holger Schmidt Burcin Aksoy Franz J.Hauck Andreas Kassler Institute of Distributed Systems Ulm University Germany Department of Computer Science Karlstad University

More and more people use voice over IP instead of traditional phone *** Session Initiation Protocol (SIP),a protocol for session management in general,becomes the standard protocol in ***,SIP relies on central ***,maintaining the infrastructure is *** results in the trend to transfer peer-to-peer (P2P) concepts to SIP to overcome administration efforts due to self-organisation of the *** this paper,we propose a novel JXTA-based P2P architecture for SIP *** is an open peer-to-peer platform,which provides basic infrastructure services for building P2P *** concept does not need central entities for maintaining the SIP traffic,while maintaining compatibility with standard ***,we seamlessly added service location capabilities into our infrastructure to support service discovery in dynamic *** evaluated our concept in comparison to standard SIP within three scenarios: local area network,point- to-point network and wide area *** results show that our approach compares well in terms of response time but results in more traffic for maintaining the peer-to-peer overlay.

关键词： Protocol How well does JXTA fit Peer-to-Peer SIP

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On the Trade-Off between Efficiency and Congestion in Location-Aware Overlay Networks - Example of a Vertical Handover Support System

On the Trade-Off between Efficiency and Congestion in Locati...

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International Conference on Peer-to-Peer Computing

作者： Thomas Zinner Simon Oechsner Tobias Hossfeld Phuoc Tran-Gia Institute of Computer Science Department of Distributed Systems University of Würzburg Wurzburg Germany

Introducing location-awareness in overlay networks allows for a higher efficiency of the offered services, e.g., shorter search times or higher throughput. This is especially important for business applications supported by overlays. In this paper, we will illustrate how such an increase in efficiency causes congestion in an otherwise well-dimensioned locality-aware overlay using a distributed Hash Table (DHT). In particular, we will use a Vertical Handover (VHO) support system using a Pastry substrate as an example. We will describe the occuring congestion problem and identify the underlying reasons. Thus, we describe the basic trade-off between efficiency and load-inequality. Furthermore, we introduce a solution for the specific issue observed, and conduct a performance evaluation identifying the major influence factors and optimization potential for future work.

关键词： Peer to peer computing Wireless LAN 3G mobile communication Mobile communication Routing Layout Databases

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Assistive technology in everyday living - A user survey of people with Parkinson's disease

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Technology and Disability 2008年第4期20卷 271-282页

作者： Muras, Joanna A. Stokes, Emma K. Cahill, Vinny Distributed Systems Group Department of Computer Science Trinity College Dublin Dublin Ireland Department of Physiotherapy School of Medicine Trinity College Dublin Dublin Ireland Department of Physiotherapy Trinity Centre for Health Sciences St. James's Hospital Dublin 8 Ireland

The aim of this study was to explore the individual circumstances of people with Parkinson's disease, as well as their ideas and opinions about assistive technology that may be used for daily living. A self-reported, user survey was designed. The results of the study were derived from a postal survey of randomly chosen members of the Parkinson's Association of Ireland. Analysis were conducted on data from 59 people. According to the survey results the majority of the participants reported problems with mobility (88%), fatigue (54%), and getting tired fast (70%). Problems with mobility included changing location (59%) and body position (51%-53%). Thirty four and twenty five percent of respondents described their physical strength and flexibility, respectively, as 'poor' or 'very poor'. For 81% of participants it was important to be able to contact someone in a case of a fall. The results of this study indicate a possible underutilisation of assistive technologies and technology by people with Parkinson's disease. In addition, the study identifies areas in which there is a demand for assistive technologies. © 2008 IOS Press. All rights reserved.

关键词： Activities of daily living Fatigue Mobility Parkinson's disease Physical difficulties Self-reported survey

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A middleware for location-based mobile applications with privacy protection 08

A middleware for location-based mobile applications with pri...

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10th International Conference on Information Integration and Web-based Applications and Services, iiWAS 2008

作者： Jorns, Oliver Quirchmayr, Gerald Research Centre Telecommunication Vienna Donau-City Strasse 1 1220 Vienna Austria University of Vienna Faculty of Computer Science Department of Distributed and Multimedia Systems Liebiggasse 4/4-6 A-1010 Vienna Austria

ISBN: (纸本)9781605583495

Network operators gradually open their interfaces to formerly hidden services. This fosters the development of a new class of mobile applications that take into account context information such as the location of users. However, the development of location-based services also raises the issue of users location-privacy. In this paper we introduce a service architecture that aims to overcome some of the shortages of currently existing context-aware applications by applying a novel pseudonym based privacy enhancing mechanism that is based on the notion of pseudonyms. This mechanism can even be applied on legacy mobile devices with restricted memory or processing power. Due to its flexibility many different kinds of applications are conceivable. One of the most important aspects in this respect is the highly postulated pay-as-you-go model. To illustrate our approach we demonstrate a transport ticket application that is extended by location-tracking functionality. © 2008 ACM.

关键词： Location based services

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Controlling Physical Objects with Privacy using Secure RFID System

Controlling Physical Objects with Privacy using Secure RFID ...

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New Technologies, Mobility and Security (NTMS)

作者： Fahad Samad Sadeq Ali Makram Department of Computer Science Communication and Distributed Systems Informatik 4 RWTH Aachen University Germany

Security and privacy threats in technological environment are great hindrances to use latest technologies for our benefits. Such threats also exist in RFID systems which are currently utilized to a great extent in ubiquitous communication. These systems can also work in combination with cellular networks to control user's physical objects in a secure way with sufficient privacy. This paper presents a secure system model which enables a user to control his possessions even sitting remotely from the objects' locations. The limitations of RFID tags are taken into account and it is shown that the system mitigates many threats keeping the privacy of the tags and the user intact.

关键词： Control systems Privacy Radiofrequency identification RFID tags Ubiquitous computing Communication system security Communication system control Information security Land mobile radio cellular systems Pervasive computing

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Wikipedia in Action: Ontological Knowledge in Text Categorization

Wikipedia in Action: Ontological Knowledge in Text Categoriz...

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International Conference on Semantic Computing

作者： Maciej Janik Krys J. Kochut Large Scale Distributed Information Systems Lab Department of Computer Science University of Georgia USA

ISBN: (纸本)9781424432035

We present a new, ontology-based approach to the automatic text categorization. An important and novel aspect of this approach is that our categorization method does not require a training set, which is in contrast to the traditional statistical and probabilistic methods. In the presented method, the ontology, including the domain concepts organized into hierarchies of categories and interconnected by relationships, as well as instances and connections among them, effectively becomes the classifier. Our method focuses on (i) converting a text document into a thematic graph of entities occurring in the document, (ii) ontological classification of the entities in the graph, and (iii) determining the overall categorization of the thematic graph, and as a result, the document itself. In the presented experiments, we used an RDF ontology constructed from the full English version of Wikipedia. Our experiments, conducted on corpora of Reuters news articles, showed that our training-less categorization method achieved a very good overall accuracy.

关键词： Ontologies Encyclopedias Internet Text categorization Information services Electronic publishing Training

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Rescheduling co-allocation requests based on flexible advance reservations and processor remapping

Rescheduling co-allocation requests based on flexible advanc...

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International Workshop on Grid Computing

作者： Marco A. S. Netto Rajkumar Buyya Grid Computing and Distributed Systems Laboratory Department of Computer Science and Software Engineering University of Melbourne Australia

Large-scale computing environments, such as TeraGrid, distributed ASCI Supercomputer (DAS), and Gridpsila5000, have been using resource co-allocation to execute applications on multiple sites. Their schedulers work with requests that contain imprecise estimations provided by users. This lack of accuracy generates fragments inside the scheduling queues that can be filled by rescheduling both local and multi-site requests. Current resource co-allocation solutions rely on advance reservations to ensure that users can access all the resources at the same time. These coallocation requests cannot be rescheduled if they are based on rigid advance reservations. In this work, we investigate the impact of rescheduling co-allocation requests based on flexible advance reservations and processor remapping. The metascheduler can modify the start time of each job component and remap the number of processors they use in each site. The experimental results show that local jobs may not fill all the fragments in the scheduling queues and hence rescheduling co-allocation requests reduces response time of both local and multi-site jobs. Moreover, we have observed in some scenarios that processor remapping increases the chances of placing the tasks of multi-site jobs into a single cluster, thus eliminating the inter-cluster network overhead.

关键词： Time factors Estimation Runtime Schedules Resource management Processor scheduling Supercomputers

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A Meta-scheduler with Auction Based Resource Allocation for Global Grids

A Meta-scheduler with Auction Based Resource Allocation for ...

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International Conference on Parallel and distributed systems (ICPADS)

作者： Saurabh Kumar Garg Srikumar Venugopal Rajkumar Buyya Grid Computing and Distributed Systems Laboratory Department of Computer Science and Software Engineering University of Melbourne Australia

As users increasingly require better quality of service from grids, resource management and scheduling mechanisms have to evolve in order to satisfy competing demands on limited resources. Traditional schedulers for grids are system centric and favour system performance over increasing userpsilas utility. On the other hand market oriented schedulers are price-based systems that favour users but are based solely on user valuations. This paper proposes a novel meta-scheduler that unifies the advantages of both the systems for benefiting both users and resources. In order to do that, we design a valuation metric for userpsilas applications and computational resources based on multi-criteria requirements of users and resource load. The meta-scheduler maps user applications to suitable distributed resources using a continuous double auction (CDA). Through simulation, we compare our scheduling mechanism against other common mechanisms used by current meta-schedulers. The results show that our meta-scheduler mechanism can satisfy more users than the others while still meeting traditional system-centric performance criteria such as average load and deadline of applications.

关键词： Resource management Processor scheduling Cost accounting Grid computing Computational modeling Environmental economics Laboratories computer science Software engineering Quality of service

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Parallel distributed Processing of Constrained Skyline Queries by Filtering

Parallel Distributed Processing of Constrained Skyline Queri...

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IEEE 24th International Conference on Data Engineering (ICDE 2008), vol.2

作者： Bin Cui Hua Lu Quanqing Xu Lijiang Chen Yafei Dai Yongluan Zhou Department of Computer Science Peking University China Department of Computer Science University of Aalborg Denmark Distributed Information Systems Laboratory EPF Lausanne Switzerland

ISBN: (纸本)9781424418367;1424418364

Skyline queries are capable of retrieving interesting points from a large data set according to multiple criteria. Most work on skyline queries so far has assumed a centralized storage, whereas in practice relevant data are often distributed among geographically scattered sites. In this work, we tackle constrained skyline queries in large-scale distributed environments without the assumption of any overlay structures, and propose a novel algorithm named PaDSkyline (Parallel distributed Skyline query processing). PaDSkyline significantly shortens the response time by performing parallel processing over site groups produced by a partition algorithm. Within each group, it locally optimizes the query processing over distributed sites. It also drastically enhances the network transmission efficiency by performing early reduction of skyline candidates with deliberately selected multiple filtering points. Results of extensive experiments demonstrate the efficiency and robustness of our proposals.

关键词： distributed processing Partitioning algorithms Filtration query analysis Reaction Time Distribute Parallel Lines

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