Advanced Engineering Forum Vols. 2-3

Abstract: Shadows bring some undesirable problems in computer vision, such as object detecting in outdoor scenes. In this paper, we propose a novel method for cast shadow detecting for moving target in surveillance system. This measure is based on tricolor attenuation model, which describes the relationship of three color channel’s attenuation in image when shadow happens. According to this relationship, the cast shadow is removed from the detected moving area, only the target area is left. Some experiments were done, and their results validate the performance of our method.

Abstract: Active vibration control use an active force from secondary path to suppress or attenuate periodic or quasi-periodic vibration and noises, one of the popular control algorithms is filtered-x least mean square (FxLMS) adaptive method. Based on structure of FxLMS algorithm, the paper uses Level-2 S-fun to create a new FxLMS blocks in Matlab/Simulink and apply it on vibration active control system simulator. Results of computer simulation showed the custom FxLMS block’s feasibility and control algorithm’s efficiency. On the condition of stabilization, behavior analysis was also taken out by adjusting the interior parameters, including the number of Weights and the Step size.

Abstract: A PLC is more sensitive in noise than other wired communication system that is cable, DSL, and optical LAN. Therefore it considered as a crucial point in commercialization of PLC. For the commercialization of PLC, noise reduction and cancelation technique are needed. Therefore, it is definitely required to analyze and interpret the effects and types of the noise, exactly. The purpose of this work is to separate and extract the various noise of power line from data signals.

Abstract: In this paper, we developed and tested the effective gas safety management system by using wireless intelligent gas safety appliances to monitor gas flow and pressure, earthquake in a micom-gas-meter, to check combustible gas leaks and temperature (upper 100°C) in an automatic extinguisher and to measure smoke and CO gas. Then our system takes safety measures such as cutoff, warning and messages to protect a serious risk if results of event are abnormal, communicates with a wall-pad including a gateway with ZigBee network in buildings and to inform the event to user via the safety management program in our server. Also, the inner cutoff valve of intelligent gas meters and automatic extinguishers are operated automatically if irregular events are occurred.

Abstract: The study, one of the important solutions in the Call-center about the Call Management System Server and the Call Management System Server than that of the current situation and the advantages and disadvantages of using the measures studied and improved integration of future models of the proposed statistical solution.

Abstract: This paper studies hysteretic effect of machine-tool guideway system with clearance, establishes the nonlinear dynamics model of guideway system with symmetric clearance, and obtains the equivalent damping and equivalent stiffness coefficients using asymptotic method. With the use of time-domain graph, frequency-domain graph, phase trajectory figure, Poincare section figure, bifurcation diagram, and lyapunov exponent figure, the dynamics response of damping and external vibration frequency effect on system is studied. The result shows that the period, double-period and chaos movement will occur when the system parameters change in certain range.

Abstract: The initial cooling temperature has important effect on the bending change and section size of rolled heavy rail, when rolled heavy rail is on the cooling bed for natural cooling. In the paper, the heat-stress couple method is adopted to carry on numerical simulation to cooling process of 60kg/m U75V heavy rail, and we has obtained the bending change value and section size of rolled heavy rail in different initial cooling temperature. The study is of great reference value on the design of cooling bed which is for hundred-meter high speed heavy rail and the formulation of cooling technological parameters.

Abstract: As the heart of continuous caster, crystallizer is the cradle of most surface deficiencies and inside quality problems in steel blank. Steel blank surface quality, nonmetal impurity content and relevant distribution rely on the steel fluid solidification behavior namely steel fluid flow field distribution on great extent. For the high temperature steel fluid has big kinetic energy, so, the immixture dregs, solidification heat conduction, temperature field distribution in crystallizer, solidification blank shell thickness distribution and continuous caster blank quality were influenced by steel fluid flow. The numerical simulation analysis on flow field and temperature field in crystallizer were conducted in this paper. Three dimensions turbulent flow model was adopted to computate flow field. The heat conduction was ignored on draw blank direction in temperature field. The conjugate heat conduction model of ANSYS CFX was adopted to analyze temperature field, which can consider heat conduction in solid layer and convection heat conduction between solid shell face and fluid simultaneity. The draw blank velocity was found by setting crystallizer water gap insertion depth and crystallizer water gap angle, which can obtain reasonable flow field in blank crystallizer.

Abstract: In the case of considering the shear effect and gyroscopic effect, a finite element model is developed to study the nonlinear dynamic behavior of a double-disk isotropic rotor- bearing system with axial rub-impact in this paper. The influences of rotational speed and initial phase difference on the operation stability of the rotor-bearing system are discussed. It transpires that the response of the rotor system with axial rub- impact is mainly synchronous periodic motion. The vibration signals of axial rub-impact include such as the synchronous signal and the multiple frequencies, in which the synchronous signal is dominating signal. There is no weakening wave phenomenon in time wave plot. All the results are in reasonable good agreement with those observed in engineering. The results of this paper could provide certain reference for fault diagnosis and self-healing of large high-speed rotating machinery system, thus ensuring the safe operation of the system.

Abstract: This paper focus on rotor-bearing system parameter identification with impulse excitation in horizon and vertical which is based on Backward -auto-regressive model. Singular value decomposition is applied to reduce the noise and the proper AR model order and de-noising threshold are selected. In this paper, the damping ratio is identified within the different rotating speed and different impulse excitation, and the error is calculated within the different noise level and different AR model order when compared with the ideal model. Though the theoretical analysis, simulation analysis and experimental research, We can indicate that the BAR model has a good performance in system identification and elimination of false modal.