Key Engineering Materials Vols. 480-481

Abstract: The primary goal of this research is to keep the good performance of the LANs communications pass through the five categories of unshielded twisted pair. This is a working theory based on the idea that is to illustrate the optimizing character of Hub-spoken topology. The foundation and the features of Hub-spoken topology and the five categories of unshielded twisted pair are explained in detail. The concept of the dependable margin motion coefficient was put forward on the basis of the margin motion coefficient and the reliability coefficient. This research aims at providing the best solutions of Hub-spoken topology to improve performance of the LANs communications.

Abstract: Rapid prototyping (RP) is a digital manufacture technology based on discrete stacking technology. RP technology can be used to machine complex physical part directly from CAD data without any professional apparatus. The paper also summarized four main RP technologies, discussed the working principle and compared the application fields, machining cost and process parameters in detailed. Finally, the author prospected the significant performance of RP for modern industry, analyzed the merits and faults and indicates the development object for RP technology.

Abstract: Some data in the field of the database often need to be automatically increased in many applications. It is presented in this paper that the increase can be realized by form pattern, which can get over the shortcoming of the meanings that present database adopts autonomous increase field or sequence. The method is proved feasible and easy by which is developed and used in some ship management and information system.

Abstract: Monte Carlo (MC method) of the computer simulation of the traditional forms of light-emitting diode (LED) is used for modeling and simulation. MC method than the method of geometrical optics of the LED is more suitable for complex optical structure on a Computer. MC method, the more accurate numerical solutions can improve the efficiency of LED design that is an effective means of LED design. MC method is with a very clear and unique advantage in the establishment of LED structure model.This paper first introduces the research background and purpose of the LED, then Monte Carlo methods Are outlined, and finally, some mathematical models of LED are given based on Monte Carlo method

Abstract: In order to analyze the influence of flat rate on mechanical character of large-span tunnel structure, the structural analysis of three flat rates in four-lane tunnel with single arch is progressed by the compiled procedure of load structure model. The result shows that the lower flat rate is, the more unfavorable structural stress is and the more unstable surrounding rock is, the optimal flat rate of four-lane tunnel is 0.65.

Abstract: For power distribution systems, recognizing the single-phase ground fault is very difficult because there are several faults with similar features. This paper presents a novel method that can help to overcome this difficulty. The idea is to turns the original fault info into a whole system with transient state, steady state and transition state. Theoretical analysis, computer simulation and lab experiments verified the effectiveness of the proposed method.

Abstract: Air quality is very important for classrooms where high density of students study for long time. Enhanced ventilation is an idea way to introduce more fresh air to classroom. Hybrid ventilation combined natural ventilation with mechanical ventilation is a economic way for ventilation improvement. factors Influencing hybrid ventilation such as heat source intensity, location of air inlet, air velocity were studied by simulation in this paper. The characteristics of temperature distribution of the classroom were also analyzed. The simulation research was validated by model experiments. A low position of air inlet in the room makes high temperature efficiency, the optimal value of the air inlet velocity is about 0.5 m/s.

Abstract: Vision sensor for weld seam location and seam tracking is developed. It is difficult for realizing picture precise identification based on machine welding at present, the image recognition algorithm based on wavelet analysis is designed in this paper. It uses immune genetic algorithm to optimize wavelet coefficient, and extracts the edge of picture preferably. In the process of detecting edges, compared with the others, the algorithm can inhibit the interference of noises effectively and remove artifacts of edges, which make the detected edge clearly and carefully. The result shows that the wavelet analysis algorithm has better effect for weld seam recognition.

Abstract: The rapid development of Internet is pushing the e-Business to go to the front stage. Online authentication involves much more than the obvious identification and validation problem. We present here a comprehensive framework for online authentication which has several important practical benefits. Our distributed E-Business authentication scheme based on conic curve is proposed. This scheme is composed of three parts, constructing license and validating license. Because the security of license is determined by private key, not the arithmetic itself, user can not construct new license by given license and the public key as long as the private key is not leaked. Since encoding and decoding over conic are easily implement on conic curves, it has enabled our scheme to greatly enhance efficiency. We also analysis its security. The entire process guarantees the security and reliability.

Abstract: With the computer and the rapid development of information technology, The plant disease intelligence diagnosis and the plant disease early warning network is possible. In this paper, relying on the Internet, the realization of intelligent online plant disease diagnosis, early warning, prevention and other information query and forecasting capabilities. The database base on Internet-based wide area network environment and the help of webGIS technology, including diagnostic module, check module and the prediction module. The intelligent prognosis is tested to the extent and happening of plant diseases, for example, Wheat, cotton, tomatoes and other 12 kinds of plant diseases, and epidemic curve is given. To disease diagnosis and prediction of the professional, technical problems become easy, for the effective control of plant diseases, provide a reference.