Applied Mechanics and Materials Vols. 457-458

Abstract: A remote supervisory system of classroom lighting based on LonWorks fieldbus is presented, which controls the switch state of lights and the number of lights to turn on, achieving the purpose of energy saving. The administrator can remotely know the situation of each classroom, and be able to perform manually control. The experiment results show that the proposed supervisory system has the qualities of easy to implement, high reliability, and easy to expand.

Abstract: Based on the principle of ultrasonic transit time ranging, this article describes that the microcontroller is used as the core to develop the ultrasonic distance-measurement automobile-reversing radar control system. The system includes both hardware and software parts. The hardware part mainly consist single-chip control circuit, ultrasonic transmitting and receiving circuits, temperature compensation circuit and voice alarm circuit. The software design part of the system was divided into several function modules with modular design method, such as main program module, temperature measurement module, voice alarm module and so on. The main program was responsible for dispatching management all the modules. Experiments show that this system can reach design requirement and has high value and broad application prospects.

Abstract: with the rapid development of information technology, a variety of data acquisition and processing in the modern industrial control and scientific research have become an indispensable part. The data acquisition system is a bridge between the smart instruments and the outside physical world, and it is also an important way to get information. The implementation of high-speed data acquisition and real-time transmission has always been an important research direction in data acquisition system. The development of FPGA technology has provided new solution. In this paper, the typical architecture of data acquisition system was given. The hardware part mainly consists of front high-speed A/D converter module, master controller of FPGA, and USB interface circuit has been realized. According to the idea of design and the procedure of program, software part has been completed. The results show that the system has the characteristics of fast acquisition speed, high storage capacity, small transmission delay, high stability and so on.

Abstract: How to realize the audio spectrum displayer system based upon ARM is introduced in detail. The system includes functions as collecting, processing, displaying after transforming of audio signals. With sound collecting, ARM technology and FFT algorithm, the design builds a real-time collecting spectrum display system, which can be put into various applications in which sounds need collecting and analyzing. The design consists of hardware system and software system. The former mainly includes the collecting and processing of sounds, the minimum system, electronic power and displayer module, while the later is to display the data transformed by ADC with FFT on the displayer. The design has been proved real-time and accurate after test.

Abstract: For collectors pressure system strong interference, coupled, nonlinear, multi-parameter and other characteristics, based on the inverse system decoupling principle, the reversibility of the mathematical model of the gas collectors pressure system is analyzed. BP neural network which has strong nonlinear approximation ability is applied, to approximate inverse system of gas collectors pressure system. Neural network inverse system with the original system composes of the pseudo linear decoupling composite system. The neural network inverse decoupling control of gas collectors pressure system is implemented. The simulation results show that this method realizes decoupling, has a certain application.

Abstract: With the rapid development of biometric technology, the security issues have drawn people's greater attention because some biometric features are Easy to forge and are not replaceable. As a result, the security issue of biometric system extremely critical to be solved. In this paper, we introduce a public watermarking algorithm which is based on Discrete Cosine Transformation (DCT). By using the proposed algorithm, the finger geometry is embedded into the region of interest (ROI) of palmprint image. This method has the ability to increase the security of both the palmprint image and the finger geometry. Experimental results performed on a database of 86 hands (10 impressions per hand) show that the proposed algorithm is effective, and the watermarking operation has little impact on the recognition performance.

Abstract: Because the sinter mixture moisture control system has time-varying, nonlinear and time-delay characteristics, it is difficult to establish its precise mathematical model. According to the defects that the conventional PID control in the fixed parameter is difficult to guarantee the system performance, this paper proposed the parameter self-tuning fuzzy PID controller which is used to the system. Based on the sintering furnace structural features and control performance requirements, the PID parameters are set by fuzzy logic reasoning. The actual operation results proved that the parameter self-tuning fuzzy PID controller improved more obviously the system performance than the original PID controller, and stabilized the sinter mixture moisture, and improved the sintering production condition and promoted the production capacity.

Abstract: In order to solve the problem of inconvenience for integration and operation complexity, the micro-flow fluid supply system based on STC12 series MCU is presented and implemented. STC12 has many advantages such as ultra-low power consumption, rich chip designs, high performance cost ratio, high speed, etc. The feeding system mainly consists of mechanical parts, a miniature stepper motor, a micro-stepping driver, MCU and its control circuit. The software program is written by PC to manage the feeding process of the start-stop, rotation direction, acceleration and deceleration of the motor. Both the flow rate and the flow flux can be controlled precisely and flexibly, so as to ensure that the test liquid is slowly delivered under quasi-equilibrium condition to shape into a satiated and uniform drop.

Abstract: Computational Fluid Dynamics (CFD) simulation often needs to periodically output the intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. Traditional CFD simulation takes ASCII format with typesetting in the snapshot output process, which results in precision loss of the data in the snapshot array and more storage space occupancy than the original binary format. In this paper, we propose the binary non-typesetting format optimization for the snapshot output in CFD simulation, aiming at eliminating the impact of ASCII format. In our optimization method, the snapshot array is output in binary format without typesetting. On one hand, it reserves the original binary precision in the output files, while the ASCII format always has precision loss, which seriously impacts the accuracy of CFD simulation; On the other hand, non-typesetting provide the opportunity of output the snapshot as a continuous memory block, which will signally improve the efficiency of the output. We design the multiply output mode framework for CFD applications through the combination of ASCII typesetting format and binary non-typesetting format. We implement this multiply output mode framework in the open source CFD software OpenFOAM. Experimental results on Tianhe-2 supercomputer demonstrate that our binary non-typesetting format optimization technique can achieve good optimization effect for the periodical snapshot output in CFD application.

Abstract: By analyzing the problem of k-means, we find the traditional k-means algorithm suffers from some shortcomings, such as requiring the user to give out the number of clusters k in advance, being sensitive to the initial cluster centers, being sensitive to the noise and isolated data, only being applied to the type found in globular clusters, and being easily trapped into a local solution et cetera. This improved algorithm uses the potential of data to find the center data and eliminate the noise data. It decomposes big or extended cluster into several small clusters, then merges adjacent small clusters into a big cluster using the information provided by the Safety Area. Experimental results demonstrate that the improved k-means algorithm can determine the number of clusters, distinguish irregular cluster to a certain extent, decrease the dependence on the initial cluster centers, eliminate the effects of the noise data and get a better clustering accuracy.