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Sharing System (sharing + system)

Distribution by Scientific Domains

Business, Economics, Finance and Accounting	37%
Engineering	25%

Selected Abstracts

Performance analysis and improvement for BitTorrent-like file sharing systems

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2007
Ye Tian
Abstract In this paper, we present a simple mathematical model for studying the performance of the BitTorrent (http://www.bittorrent.com) file sharing system. We are especially interested in the distribution of peers in different states of the download job progress. With the model we find that the distribution of the download peers follows an asymmetric U-shaped curve under the stable state, due to BitTorrent's unchoking strategies. In addition, we find that the seeds' departure rate and the download peers' abort rate will influence the peer distribution in different ways notably. We also analyze the content availability under the dying process of the BitTorrent file sharing system. We find that the system's stability deteriorates with decreasing and unevenly distributed online peers, and BitTorrent's built-in ,tit-for-tat' unchoking strategy could not help to preserve the integrity of the file among the download peers. We propose an innovative ,tit-for-tat' unchoking strategy which enables more peers to finish the download job and prolongs the system's lifetime. By playing our innovative strategy, download peers could cooperate to improve the stability of the system by making a trade-off between the current downloading rate and the future service availability. Finally, experimental results are presented to validate our analytical results and support our proposals. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Performance evaluation of LIBTA/hybrid time-slot selection algorithm for cellular systems,

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2001
Jyh-Horng Wen
Abstract This paper studies the performance of radio assignment algorithms for portable access in cellular systems. Several channel access procedures are proposed and simulated using block oriented network simulator (BONeS) simulation of a model 36-port system. Simulation results exhibit that load-sharing system with LIBTA algorithm is better than directed retry system with the same algorithm by around 0.9 erlangs while better than quasi-fixed channel assignment (QFCA) system by around 2 erlangs if the grade of service (GOS) is constrained to less than 10 per cent. Plus, a hybrid time-slot selection procedure is proposed to enhance the system performance. It is observed that systems with hybrid time-slot selection perform better than those with LIBTA algorithm in GOS under heavy load. It is also observed that load sharing system with hybrid time-slot selection algorithm is better than directed retry system with the same algorithm by around 0.7 erlangs and better than QFCA system by around 2 erlangs. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Building community knowledge systems: an empirical study of IT-support for sharing best practices among managers

KNOWLEDGE AND PROCESS MANAGEMENT: THE JOURNAL OF CORPORATE TRANSFORMATION, Issue 3 2003
Jørgen P. Bansler
The paper reports a field study of knowledge sharing in a large and complex organization. The objective of the study was to gain an in-depth understanding of the implementation and use of a web-based knowledge sharing system designed to facilitate the circulation of best practices among middle managers. We followed the system from its introduction in early 1997 until it was abandoned in the beginning of 2000. We focused on the way the system was introduced in the organization, how it changed, and how the intended group of users received (and eventually rejected) the system. Based on our interviews and observations we identify five reasons for the systems failure. We close the paper by some reflections on the use of the concept of ,shared practice' in the development of IT-supported knowledge sharing systems. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Online knowledge sharing in a multinational corporation: Chinese versus American practices

PROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2007
Wei Li
In-depth interviews were conducted with Chinese and American users of a knowledge sharing system, pseudo-named Knowledge Everywhere (KE), being employed by a Fortune 100 company with operations in over 100 countries. The intent of these interviews was to identify factors influencing knowledge sharing behaviors among Chinese and American users of the KE system. Interview questions were framed using the Unified Theory of Acceptance and Use of Technology (Ventakesh, et al., 2003). Three primary conclusions emerged from the findings generated from the interviews. First, there is a perceived disconnect between knowledge sharing system usage and daily job performance. Second, language appears as a one-way barrier to knowledge sharing and not two-way as many practitioners believe. Third, cultural conservatism and perceived differences in practices hinders Chinese users' willingness to share and as a result gives the false impression that Chinese employees hoard information. [source]

Double trouble: the importance of accounting for and defining water entitlements consistent with hydrological realities,

AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 1 2009
Michael D. Young
When entitlements to access water in fully allocated river and aquifers are specified in a manner that is inconsistent with the ways that water arrives, flows across and flows through land, inefficient investment and water use is the result. Using Australia's Murray Darling Basin as an example, this paper attempts to reveal the adverse economic and water management consequences of entitlement and water sharing regime misspecification in regimes that allow water trading. Markets trade water products as specified. When entitlements and the water sharing system are not designed in a way that has hydrological integrity, the market trades the water management regime into trouble. Options for specification of entitlement and allocation regimes in ways that have hydrological integrity are presented. It is reasoned, that if entitlement and allocation regime are set up in ways that have hydrological integrity, the result should be a regime that can autonomously adjust to climatic shifts, changes in prices and changes in technology without compromising environmental objectives. [source]

Performance analysis and improvement for BitTorrent-like file sharing systems

Suppression of sidelobes in OFDM systems by multiple-choice sequences,

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2006
Ivan Cosovic
In this paper, we consider the problem of out-of-band radiation in orthogonal frequency-division multiplexing (OFDM) systems caused by high sidelobes of the OFDM transmission signal. Suppression of high sidelobes in OFDM systems enables higher spectral efficiency and/or co-existence with legacy systems in the case of OFDM spectrum sharing systems. To reduce sidelobes, we propose a method termed multiple-choice sequences (MCS). It is based on the idea that transforming the original transmit sequence into a set of sequences and choosing that sequence out of the set with the lowest power in the sidelobes allows to reduce the out-of-band radiation. We describe the general principle of MCS and out of it we derive and compare several practical MCS algorithms. In addition, we shortly consider the combination of MCS sidelobe suppression method with existing sidelobe suppression methods. Numerical results show that with MCS approach OFDM sidelobes can be reduced significantly while requiring only a small amount of signalling information to be sent from transmitter to receiver. For example, in an OFDM overlay scenario sidelobes power is reduced by around 10,dB with a signalling overhead of only 14%. Copyright © 2006 AEIT. [source]