A. R. ZOLGHADR ASLI; B. AMIN SHAH; M. A. MASNADI SHIRAZI; M. H. GHAMAT
Volume 4, Issue 2 , July 2006, Pages 1-14
Abstract
One of the limitations of orthogonal frequency division Multiplexing (OFDM) in many applications is its sensitivity to frequency shifts, errors normally referred to as carrier frequency offset (CFO). Although, this small offset is negligible in conventional single carrier communication systems, it ...
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One of the limitations of orthogonal frequency division Multiplexing (OFDM) in many applications is its sensitivity to frequency shifts, errors normally referred to as carrier frequency offset (CFO). Although, this small offset is negligible in conventional single carrier communication systems, it is a severe problem in the OFDM systems. Because, the carriers in OFDM are inherently closely spaced in frequency, the tolerable frequency offset becomes a very small fraction of the channel bandwidth. Besides, for OFDM communication systems, the frequency offset in mobile radio channels distorts the orthogonality between subcarriers, resulting in intercarrier interference (ICI). In this paper, we analyze and compare the performance of some already existing methods for reducing ICI with new ICI cancellation schemes by simulation. Also the advantage of using a coding scheme is shown.
F. Nassiri-mofakham; M.A. Nematbakhsh; N. Ghassem-aghaee; A. Baraani-dastjerdi
Volume 4, Issue 2 , July 2006, Pages 15-38
Abstract
The area of bargaining mechanisms has been well explored in both multi-agent systems and economics. In bargaining, participants raise/reduce their offers until an agreement is hopefully reached. In this dynamic environment, finding superior agreements without having the knowledge about the strategic ...
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The area of bargaining mechanisms has been well explored in both multi-agent systems and economics. In bargaining, participants raise/reduce their offers until an agreement is hopefully reached. In this dynamic environment, finding superior agreements without having the knowledge about the strategic private information of the counterpart is considerable. In this paper, we present a simple semi-dynamic cooperative bargaining, which deals with bargaining of single-buyer and single-seller in a multi-criteria single-good e-Marketplace. Both buyer and seller are equipped with medial agents that cooperatively want to win bargaining via a slight maneuver, over their own preferences that are unknown to each other. We show the results obtained using the simulation. This approach shows that the lack of intersection between threshold utility intervals of both parties does not necessarily yield a disagreement. On the other hand, if the party whose utility threshold is lower than the utility threshold of the other party makes the initial offer, the two parties will certainly have an agreement in a single round.
M. M. El-Khouly
Volume 4, Issue 2 , July 2006, Pages 39-45
Abstract
Many important and useful applications for software agents require multiple agents on a network that communicate with each other. We often use the word “agent” to describe people who have a helping or assistive relationship to us –– travel agents, secretaries, butlers. The ...
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Many important and useful applications for software agents require multiple agents on a network that communicate with each other. We often use the word “agent” to describe people who have a helping or assistive relationship to us –– travel agents, secretaries, butlers. The job of such an agent is to act autonomously to satisfy goals that we may have, give us a greater sense of productivity and reduce our workload. In this article we’ll use the word agent to describe software that plays a similar role – providing help, advice, and work as a broker who has several software components and can assign one for the user. Such agents can retrieve software components for reuse from their repositories. However, if the keywords of the retrieving disaccords, the retrieval can be failure even if the eligible components exist in the component repository. We propose an information retrieval technique to help in retrieving the software components from the repositories. This technique uses three levels for retrieving components from a repository and can adapt the retrieved components to suite with the required query. The advantage of this technique is that the exact match is not necessary to find a similar software component.
Z. Hayati; P. Tajer
Volume 4, Issue 2 , July 2006, Pages 47-54
Abstract
This survey is aimed to compare the hierarchical structure of subject directories, including Yahoo, The Open Directory and Looksmart with Dewey Decimal Classification (DDC) in 10 selective subjects. Five questions are raised to compare the broadness and the depth of the hierarchical structures in ...
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This survey is aimed to compare the hierarchical structure of subject directories, including Yahoo, The Open Directory and Looksmart with Dewey Decimal Classification (DDC) in 10 selective subjects. Five questions are raised to compare the broadness and the depth of the hierarchical structures in the subject directories and DDC and to study the effectiveness of the usage of DDC in the organization of the Internet resources. The data were collected by counting links and indentions. The results show that the hierarchical structure of Looksmart is broader and deeper than Yahoo, The Open Directory and DDC. This characteristic decreases its effectiveness as a classification scheme. This study also shows that subdivisions are rather evenly distributed in different hierarchical levels of DDC in comparison to subject directories. These features in addition to their general nature make DDC a suitable instrument for organizing Internet resources.
S. Afsharnia; R. Abbasi
Volume 4, Issue 2 , July 2006, Pages 55-67
Abstract
The rate of scientific articles published in scientific journals is one of the indicators of assessing the status of science and technology. An increase in these publications is a sign of the movement of the society towards development and promotion. In this article, the rate of scientific publications ...
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The rate of scientific articles published in scientific journals is one of the indicators of assessing the status of science and technology. An increase in these publications is a sign of the movement of the society towards development and promotion. In this article, the rate of scientific publications in scientific journals (types A and B) during the years 2002 and 2003 will be analyzed. In order to investigate the statistics of the published articles in these journals, several indicators have been used. In spite of the fact that these analyses are based on two types of scientific journals, the statistics of journals in six scientific groups have also been distinguished and considered. The results showed that amongst the six scientific groups, Medical Sciences had the highest number of scientific type-A journals and articles and Humanities had the highest number of scientific type-B journals and articles in Iran.
R. Fattahi; M. Parirokh; M. R. Davarpanah; A. Azad
Volume 4, Issue 2 , July 2006, Pages 69-81
Abstract
This article is a short report of a research project carried out, upon the recommendation of the Ministry of Science, Research and Technology, by the Department of Librarianship and Information Science of Meshed Ferdowsi University between 2003-2004. The goal was to study and revise the current curriculum ...
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This article is a short report of a research project carried out, upon the recommendation of the Ministry of Science, Research and Technology, by the Department of Librarianship and Information Science of Meshed Ferdowsi University between 2003-2004. The goal was to study and revise the current curriculum to bring it closer to the changing needs of the present society. The curricula of the U.S.A., England, Australia, India and Iran were reviewed and compared with the objective of introducing a new syllabus for the two fields of Information Management and IT Management. The new curriculum was sent to some experts and faculty members of the departments of Librarianship and Information Science of Iran that ran courses at M. A. level. They were asked to issue their comments on the curriculum. Then, the final version of the curriculum was verified after undergoing some revisions by the Revising Committee of Meshed Ferdowsi University. The new curriculum was also sent to the Ministry of Science, Research and Technology to be sent to universities after being approved by the Ministry.
H. Sharif Moghaddam
Volume 4, Issue 2 , July 2006, Pages 83-96
Abstract
Various view points of the library planners about the future’s library buildings have been explained in this paper. With the advances in information technology, some librarians believe that modern and well planned library buildings are not so necessary in the future. On the other hand, many others ...
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Various view points of the library planners about the future’s library buildings have been explained in this paper. With the advances in information technology, some librarians believe that modern and well planned library buildings are not so necessary in the future. On the other hand, many others believe that more modern and well technologically equipped library buildings should be built to fulfill the future needs of the library users. Characteristics of the future library buildings have also been enumerated in this paper. The need for various spaces for computers and other information technology equipment has been emphasized throughout the paper.
