25 June 2007, Volume 25 Issue 0712

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  • . 2007, 25(0712): 5-11.
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    During the course of information technology being integrated into industrialization in the world, the simulation science and technology, as an emerging field of research, has established itself as an independent research discipline, that is, with stable research objects, a relatively independent theoretical system and a contingent of scientists and engineers for specific applications and the divers demands of the society. The theoretical system of simulation science and technology is summarized in this paper, which can be divided into fundamental theory, specialized theory and application theory, including similarity theory, simulation methodology, modeling theory, simulation system theory, simulation credibility theory and simulation application theory. Their present status and functions are discussed.
  • . 2007, 25(0712): 12-17.
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    In a train driving simulator, the performance simulation and the environment simulation are used to create a high fidelity virtual driving environment. Driving training, optimized operating and related researches (such as vehicle dynamics simulation) can be carried out on the train driving simulator. Assortment of train driving simulators is discussed. A typical architecture of a full mission simulator is introduced, based on which, key techniques of a train driving simulator are discussed.
  • . 2007, 25(0712): 18-22.
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    Railway rescheduling is a very complicated combinatorial optimization problem, which can be solved by using the simulation technique. On the basis of a model for the intelligent decision support system for railway rescheduling and using the optimization method, this paper studies the applications of the simulation technique to railway rescheduling optimization and to the simulation system for training railway dispatchers.
  • Articles
  • . 2007, 25(0712): 23-27.
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    A pair of degenerated primers was designed according to the reported Shh gene order of elasmobranch, teleost, amphibians, avifauna, mammalia and human, to amplify the Shh gene from Senegal bichir cDNA by PCR. The result shows that the Senegal bichir Shh gene is of 1 263 bp in length,with 421 amino acids. From a comparison by homology, it can be seen that lungfish and Senegal bichir share the highest homology of 82.5%. A secondary structure analysis shows Shh albumen consists of 30.71% of α helix, 21.67% of extended line and 47.62% of random coil, without β slice. To construct the three dimensional structure of Shh protein by homology using http://www.expasy.org/swissmod/SWISS-MODEL.html one establishes a good foundation for further studies on Shh gene functions in the embryonic development and the limb bud schema.
  • . 2007, 25(0712): 32-37.
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    From the 30's of the19th century to the 30's of the 20th century, with the fast development of the social productive forces and the close relation of the local economies, economists proposed various position theories, and the demand cone put forward in the position theory by economist Losch is noteworthy. In this paper, the beer demand cone is generalized into various kinds of demand cone of products to obtain the concept, the model and the influence factor of the generalized demand cone, where the technical innovation promotes "the congenetic growth" and "the heterogenous growth" of the demand cone . In the course of its growth, the technological innovation makes the cycle of the life of product shorter and shorter, with the products of old generation being replaced constantly by products of new generation. Three stages of the product cycle put forward by Veron are incorporated into the generalized demand cone model. As the demand of cone grows, the base of production spreads from the primitive one.In the process of the economic integration in the world, it serves as a theoretical model for the strategic shifts and the spatial reorganization of global industries.
  • . 2007, 25(0712): 38-45.
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    According to the grade of floodplain, the flow sediment concentration, the features of discharge process line, and the difference between flood peak and sediment peak, the flood is classified based on the data of more than 200 floods using statistical methods. The simulation experiments and mathematical models, and the key factors related with main channels formed by flood are discussed, and the key regulation indexes of flood in the lower reaches of Yellow River are studied. Results show that the flat beach discharge, which has an important effect on transport sediment and on the formation of main channels, is about 4 000 m3/s, the critical amount of transport sandiness is 50 kg/m3; the non floodplain flood or common floodplain flood should be controlled according to the flat floodplain discharge of the main channel first, and the flood discharge process would be better to take a form close to rectangular wave, and the water quantity before flood peak would be better to take a value greater than 25 % of the total water quantity, and the flood time would be better to last more than 7 d; the floodplain flood peak discharge should be controlled to be bigger than 1.5 times of flat floodplain flood peak discharge and bigger than 1.2 times of average flood discharge, and at the same time, the ratio between water quantity in swelling period and total flood should be more than 0.5, and the flood peak should be kept in step with the sandiness peak, and the flood time would be better to last more than 7 d; the content of sediment in different regulation floods is determined by the ratio of suspended sand and bed sand; the regulation indexes of flood incoming sediments should be changed according to the flood type, non floodplain flood sediment coefficient is 0.012 kg·s/m6, the common floodplain flood sediment coefficient is 0.015 kg·s/m6, and the incoming sediments of grouping sandiness should be controlled, too.
  • . 2007, 25(0712): 45-49.
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    Due to the impounding water of the Three Gorges Project (TGP), the discharge in downstream river will greatly decrease, and the water level at Hankou will also decrease, which is dangerous to the safety of the bank of Hanjiang River and the flood control in Wuhan area. Based on the analysis of the decrease of the water lever at Hankou, the threat to the bank of Hanjiang River due to the impoundment of TGP is studied, and the countermeasures are proposed in this paper.
  • . 2007, 25(0712): 50-52.
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    The radioactive Ba isotopes are produced in the interaction of 60 MeV/u 18O ions with 232Th. Ba is separated from thorium and the reaction product mixture by using BaCl2 precipitation. The ?酌-ray spectra of the Ba fractions are measured by off-line ?酌-ray spectroscopy. The cross sections of the individual Ba isotopes are obtained based on the intensities of the characteristic ?酌-ray peaks of Ba isotopes and other relative information.
  • Reviews
  • . 2007, 25(0712): 53-58.
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    Image Registration (IR) technology is a fast-growing research field during the recent decades. It is widely used in multi-spectrum image classification, environmental monitoring, change detection and image mosaicing. This paper summarizes new techniques in that field and suggests a classification according to their image model, a pixel-based model or a physically-based model. Detailed comparisons of different IR methods are given from various perspectives-theoretical and practical performances. Some interesting issues of IR in recent researches are discussed. The major goal of this paper is to present a review of new emerging IR methods, identify their principles according to image models and to cover references as comprehensive as possible.
  • 研究报告
  • . 2007, 25(0712): 58-62.
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    The factors related with the sustainable operation of the rural credit cooperatives are analyzed in this paper. Their development directions are proposed. It is shown that, for a sustainable development of rural credit cooperatives, one must pay great attention to the ability to improve the system and technology, to cultivate human resources and external environment, thus to enhance their coordination ability.
  • . 2007, 25(0712): 63-67.
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    The theory of Revenue Management (RM) was originated in aviation industry, with successful applications. Network is one of the industries where RM can be applied. But there were few researches in that area. This article proposes a design of RM strategy for Internet, similar to the techniques of RM used in airlines, which include network pricing, market segmentation and network resource allocation. It will help to solve the problem faced by Internet networks of increased sale volume with no increased revenue.
  • . 2007, 25(0712): 68-72.
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    Systems dynamics provides theories and approaches to explore complex systems. However, the optimization in a systems dynamics model still follows the "try-and-error" method, which does not work satisfactorily. According to the principles of systems dynamics, the paper proposes a general formulation for the policy optimization problem in a systems dynamics model by introducing a control policy function. Combining with genetic algorithms, , the order policy optimization in a distribution and super-market system is addressed. This paper aims to develop basic principles of systems dynamics and discuss the control and policy optimization for social economic systems.