Applied Mechanics and Materials Vols. 135-136

Abstract: Space-time block code, as one of the space-time codes, greatly improves the performance in the cooperative wireless communication systems by the use of space and time diversity. However, traditional STBC can’t enhance the overall transmission rate and there is no form of complex codes with the rate of 1 when the number of antenna is more than 2. In order to design codes with full-rate, we refer to quasi-orthogonal STBC whose generator matrix is orthogonal between its subspaces. In this paper, based on the combination of QO-STBC and Self-adaptation technology, we propose a new plan of space-time coding which dismisses the interference among symbols when decoding and advances the coding capabilities in the context of full-rate transmission, finally we justify the new plan through lots of computational simulations.

Abstract: A structure of multi-layer spiral inductor having parallel and series branches of the metal strip was designed for fully-integrated DC-DC converters. As the result that the parallel branching structure greatly reduced the series resistance and the series branching structure greatly improved the series inductance of the inductor, the structure can achieve quality factor and current capability enhancement while compatible with conventional CMOS process. The quality factor was quantitatively analyzed with a scalable model and its origin was investigated at a structural point of view. From the experiment results, the substrate effects can be neglected in the interesting frequency range, 50MHz -500MHz, and the quality factor is enhanced beyond the additional parasitic capacitance.

Abstract: This streetlight monitoring system is aimed at preventing unnecessary energy wastage by applying the GSM (Global System for Mobile Communications) technology. This system consists of two parts: the monitoring centre and the terminal nodes. The Siemens TC35 GSM module is used to send and receive short messages and it is installed in the monitoring centre and each streetlight. ATmega168 is used to determine whether or not it is necessary for the streetlights to be turned on, and then it executes commands from the control centre. When the sky is bright enough for drivers, the streetlights will automatically turn off. Also, if some streetlights are broken down, the TC35 GSM module will send an alarm short message to the monitoring centre and maintenance personnel will repair the lights as soon as possible. Thus, maintenance personnel will no longer have to make time-consuming visits to check up on the function status of every streetlight. All information is presented in the monitoring computer which is programmed in LabVIEW. The workman can easily turn on or off any streetlight by clicking on the screen.

Abstract: A new monitoring and diagnostics method using support vector data description (SVDD) is proposed which only needs samples under healthy condition. The method is an ideal candidate for coping with the problem of a shortage of the unhealthy condition samples. We firstly select several nodes of the monitored structure, and decompose the signals from these nodes with wavelet packet transform (WPT). To monitoring structural health efficiently, we assemble a combine feature by using wavelet packet energy distributions of these nodes. The feature is then applied as the input of a developed SVDD classifier. Experiment shows that the SVDD classifier was able to distinguish the normal and abnormal condition ideally, and can be used as an automation approach for structural health monitoring.

Abstract: In order to improve the safety of driving under different visibility meteorological conditions on the expressway, this paper analyses the composition and operation principle of the expressway lane departure warning and navigation system based on machine vision. And an effective lane mark identification algorithm suiting for different visibility situations is proposed. Firstly the image contrast between the expressway lane and its background is increased by using histogram equalization technology, improving detecting range of lanes and accuracy. Secondly the edges in the lane directions are detected by utilizing specific Sobel operator. In order to suit for different visibility situations and improve detecting efficiency, the method of maximum classes square error is applied to threshold segmentation. Finally, lane is abstracted according to expressway lane features after image Hough transform. Based on lanes identification, this paper designs a navigation algorithm of driving direction. This algorithm performs driving direction navigation decisions according to two characteristic parameters which are deviation angle and deviation distance. The experimental results indicate that the developed system exhibits good detection performances in recognition reliability and navigation decision. It has proved that this system has high accuracy, large detection range and high practicability.

Abstract: PAC(programmable automation controller) is a new trend of the industrial controller, but for now, most IDEs(integrated development environment) are still providing the PLC mode for users, which can not take full advantage of the PAC. Further more, in China, there is still not such IDE with complete intellectual properties for PACs designed by Chinese companies. For above purposes, the CHD-PACIDE was implemented which supported the ARM cortex-Mx series microcontrollers. This IDE consists of three layers, interface layer, data management layer and kernel layer, which managed functional modules respectively. Based on a C-like language Engineer C defined by our research team, the interface layer provided the structural graphical input mode and the text input mode for users to edit their code. The data management layer used the XML with specified format manage the flow of data. The kernel layer had two parts which were implemented in the IDE and the debug microcontroller stm8s, this layer can be used to debug user’s code through the Jtag port under the Coresight debugging structure of ARM. This IDE could be updated easily by adding the specific XML file for the new microcontroller used by the specific PAC.

Abstract: The construction machinery moving speed is an essential variable to identify its attractive performance. To realize construction machinery real-time and adaptive control, it is necessary to measure the machinery actual speed. But the traditional measurement method is not precise enough and costly too much. To search a new method, the high-speed linear CCDcamera is used to collect the road surface gray image. A machinery vision model is set up for the random road surface texture. Using cross-correlation algorithm two frame continuous image pixels are figured out. The construction machinery moving speed can be counted out by analyzing the vision model projection relationship and the two frame continuous image time.The feasibleness and precision of this method are proved by experiments.

Abstract: In the design process of surface acoustic wave (SAW) device based on multistrip coupler (MSC), the characteristics of interdigital transducer (IDT) and device can not been directly achieved, and the layout structure of device can not be observed and checked. To solve some problems, the design platform of SAW device based MSC was realized in the Matlab design environment using the modular design. The design platform of SAW device based MSC consists of layout simulation module, characteristics simulation module and data output module. By means of realizing a SAW device based MSC with center frequency at 51.293MHz, the comparison and analysis between the design results and the actual test results are presented. Experiments results confirm that the platform can correctly design the device layout. The device characteristics achieved by the design platform are in good agreement with the actual measurement results by the network analyzer.

Abstract: Secure communication with the hyper-chaos synchronization approach is the popular investigation. In this paper the fifth-order Cellular Neural Networks(CNN) hyper-chaos equation of continuous time was discreted. The innovation was that the synchronization of the hyper-chaos system was realized with the discreted reduced order state observer. Finally, the system stabilizing to zero after fugacious transition and achieving synchronization were validated by simulations, which showed the algorithm’s availability.

Abstract: Reducing start and stop time is important in enhancing productivity of double roller and compact quality of asphalt pavement, but it is difficult in confirming the max braking deceleration or starting acceleration of double-drum roller. Dynamic analysis is used and a mathematic model of double roller is established. Based on the model, the factors which affect the max braking deceleration is studied, such as braking force from hydraulic travel system, the adhesive force from ground, the inertia force from machine itself. And the max braking deceleration equation is obtained which consider the entire factors. The result indicates that drum inertia affects the max braking deceleration of double drum roller notable, and should be taken into account during design procedure and control program.