Advanced Materials Research Vols. 490-495

Abstract: By introducing dynamic keys in this paper, we present a new encryption algorithm ,which is called dynamic encryption algorithm. The algorithm allows a key to encrypt the plaintext twice, producing two ciphertexts, so that each of them is different if the time is not same. Thus chosen plaintext attacks and known plaintext attacks will become infeasible .

Abstract: Based on the working flow of an automated machine assembly line, a fuzzy expert system (FES) for fault diagnosis of the assembly line is developed, which contains user interface, knowledge base, inference engine and history database. The FES adopts fuzzy forward chaining rule-based reference strategy and can predict the severity ponderance of faults according to certainty factor. In addition, fuzzy logic and linguistic terms are also introduced.

Abstract: The vector method is applied to study the kinematic performance of the double wishbone independent front suspension.The model of the right front suspension is established in this paper, on this basis, the local motion reference frames of the upper and lower arms are established by using the coordinate transformation method. Therefore, the space relations between of the arms can be transformed into the plane motion of their respectively local reference frame by this method. Furthermore, the variable law of the wheel alignment parameters with the swing angle φ of the lower arm, is obtained through establishing the constrain equations of the key points.

Abstract: For large-capacity steam generator, piping zone diameter of U-tube section is nearly 5m, the range of U-shaped bend radius is very large from Zero meters to 2.5 meters, this affects obviously the Vibration characteristics of heat transfer tube, this effect is researched using numerical simulation. Engineering formulas of natural frequency of U-shaped tube under different conditions are given. According the vibration-type, The lowest natural frequency of U-shaped tube is plane vibration frequency of the first order for adding one anti-vibration bar or not. Natural frequency of U-shaped tube increases significantly adding anti-vibration bars to bend, which is favorable to avoid the resonance frequency and severe vibration of U-shaped tube

Abstract: A novel method of bearing fault diagnosis based on local mean decomposition (LMD) is proposed. LMD method is self-adaptive to non-stationary and non-linear signal. LMD can adaptively decompose the vibration signal into a series of product functions (PFs), which is the product of an envelope signal and a frequency modulated signal. Then the envelope spectrum is applied to the selected product function that stands for the bearing faults. Therefore, the character of the bearing fault can be recognized according to the envelope spectrum of product function. The experimental results show that local mean decomposition based envelope spectrum can effectively detect and diagnose bearing inner and outer race fault under strong background noise condition.

Abstract: Minimum ratio spanning tree(MRST) is the problem of finding a minimum spanning tree when the objective function is the ratio of two linear cost functions(such as the ratio of cost to weight). MRST problem is NP-hard when the denominator is unrestricted in sign. Cellular Competitive decision algorithm(CCDA) is a newly proposed meta-heuristic algorithm for solving combinatorial optimization problems. In this paper, a cellular competitive decision algorithm for MRST is presented. To verify the efficiency of the algorithm, it is been coded in Delphi 7, by which series of instances are tested and results result in good performance.

Abstract: The application of PLC、HMI and VVVF are introduced in constant pressure water supplying system with frequency conversion. The Principle diagram is analyzed, the Control System flow chart and Software program are designed. Through in-situ operation, the system has been proved good at reliability、stability、simplicity and intuition ，achieved constant pressure water supply and environmental protection requirements .

Abstract: An improved BP neural network prediction method is used for collecting pipe equipment failure prediction and comparing with the improved BP neural network in front, which demonstrates that the improved BP neural network algorithm to the collecting pipe failures has better predictive power.

Abstract: Cutting way is very common in the usual production, the method of solving is a hotspot. Here, we use genetic algorithm and create an innovative coding way to solve this question. It is very easy to operate, grasp furthermore also improve the calculate speed and solution quality.

Abstract: Secure end-to-end data transmission is an important method to protect the data privacy in wireless sensor networks. Authors proposed a data aggregation scheme with end-to-end security for wireless sensor networks. The plaintext of sensor readings only appeared in source node and remote server, the aggregators completed the data integrity verification, sender identity authentication and data aggregation without the plaintext. Analysis and simulation show that our scheme has higher security in terms of resilient against malicious attacks and reduces the communication overhead effectively