S. Afsharnia; S. Vaez-Zadeh
Volume 3, Issue 1 , July 2005, Pages 3-17
Abstract
The experiences by different societies reveal that consistent social and economic development results from the development of science and technology, and that the latter takes place only in a process that includes: comprehensive policy making; precise planning; determining relevant strategies and finally ...
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The experiences by different societies reveal that consistent social and economic development results from the development of science and technology, and that the latter takes place only in a process that includes: comprehensive policy making; precise planning; determining relevant strategies and finally the effective implementation of plans in different areas. Providing a clear picture of science and technology status is an essential requirement of this process. For this reason, this paper seeks to discuss, as far as possible, different aspects of S&T in Iran based on a rather comprehensive set of indicators i.e. Human Resources indicators, Financial indicators, Performance indicators and finally Productivity indicators. The objective is to review, based on the information available, the changes occurred during the years 1996, 1998 and 2000. Also, statistics of S&T in Iran is compared with those of other countries.
Z. Hayati; R. Alijani
Volume 3, Issue 1 , July 2005, Pages 18-32
Abstract
Six Web search engines, namely, Altavista, Excite, Go, Google, Hot Bot and Lycos, were compared and evaluated in terms of their search capabilities (i.e., duplicate, false drops, mirror sites, dead links) and retrieval performances (i.e., precision) using sample queries drawn from real reference ...
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Six Web search engines, namely, Altavista, Excite, Go, Google, Hot Bot and Lycos, were compared and evaluated in terms of their search capabilities (i.e., duplicate, false drops, mirror sites, dead links) and retrieval performances (i.e., precision) using sample queries drawn from real reference questions from the reference desk of the Central Library of Shiraz University (Mirzay-e-Shirazi Library). Recall, another evaluation criterion of information retrieval, is deliberately omitted from this study; because, it is impossible to assume how many relevant items there are for a particular query in the huge and ever changing Web system. The authors of this study found that Google showed the best performance, although Altavista had the largest coverage of Web resources amongst the six Web search engines examined.
N. Naghshineh
Volume 3, Issue 1 , July 2005, Pages 33-46
Abstract
Digital preservation refers to an important aspect that most Iranian digital library initiatives lack. This component is Security. While a digital library may be misconceived as an information supply space without a physical form, the same security concerns in force for operation of physical library ...
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Digital preservation refers to an important aspect that most Iranian digital library initiatives lack. This component is Security. While a digital library may be misconceived as an information supply space without a physical form, the same security concerns in force for operation of physical library are valid. Unlike the analog materials, all digital copies of digital materials are original. A digital library can provide a tool whereby the user can authenticate the same material without compromising sensitive watermark key data. Watermarks must be impervious to premeditated alterations and tampering. A national digital watermark assignment center is proposed for sharing the burden of development and distribution of such security features to content developers.
A. Zolghadrasli
Volume 3, Issue 1 , July 2005, Pages 47-56
Abstract
In this paper the author considers a general method, based on time domain samples for spectral manipulation of time limited signals. First, the original signal is divided into some frames in the time domain. Then, by presenting a suitable theoretical and computational algorithm, and using a method ...
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In this paper the author considers a general method, based on time domain samples for spectral manipulation of time limited signals. First, the original signal is divided into some frames in the time domain. Then, by presenting a suitable theoretical and computational algorithm, and using a method for improving the speed of convergence, we find the local bandwidth of each frame; thereby, each frame is sampled with a new rate, so the amount of data per frame is decreased. Finally, by storing suitable information at the beginning of each frame, the original signal could be reconstructed. Therefore, by this method some redundant data is removed and the net volume of data is reduced. The reconstruction of original signal is achieved by using periodic interpolation. In this technique, a method for reduction of error (due to false interpolation) at the end of any frame is examined carefully.
H. Bolandi; A. Badpa; M. Nasiri Sarvi
Volume 3, Issue 1 , July 2005, Pages 57-71
Abstract
When the orbital altitude of a small satellite is near-Earth, passive stabilization can be considered. The purpose of this paper is to combine the passive gravity gradient and aerodynamic stabilization methods together so that all the three axes stabilizations can be obtained. In this regard, the ...
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When the orbital altitude of a small satellite is near-Earth, passive stabilization can be considered. The purpose of this paper is to combine the passive gravity gradient and aerodynamic stabilization methods together so that all the three axes stabilizations can be obtained. In this regard, the set of nonlinear equations of motion will be solved numerically with specified initial condition. The history of the attitude stabilization will be investigated and discussed in detail. The paper demonstrates the feasibility of passive gg-aero stabilization and provides guidelines for the satellite design to obtain the best attitude performance without sacrificing satellite lifetime.
S. M. Khalesizadeh; A. Basirian Jahromi
Volume 3, Issue 1 , July 2005, Pages 72-86
Abstract
Large-Scale Allocation Problem (LSAP) is considered to be an important problem in Operations Research. In this paper, we have tried to model a sample LSAP and show that famous linear OR approaches in use cannot efficiently help us challenge, develop and handle such cases. We begin with efforts in ...
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Large-Scale Allocation Problem (LSAP) is considered to be an important problem in Operations Research. In this paper, we have tried to model a sample LSAP and show that famous linear OR approaches in use cannot efficiently help us challenge, develop and handle such cases. We begin with efforts in this area to conclude that timely, efficient and less costly solutions could be only developed under simplified models. Then, a new approach will be introduced. We have tried to introduce an algorithm and applicative method to solve a sample LSAP model and to show that famous OR approaches, in use, cannot efficiently help us challenge, develop and handle such cases. We begin with model simplification, and conclude with a sample numerical solution of university entrance exam so that the efficiency of the method can be further explained.
