Key Engineering Materials Vols. 467-469

Abstract: In this paper, a numerical modeling of contact conical transducers is discussed in conjunction with wave propagation analyses by a finite difference method (FDM). Although transducers are the devices to convert electrical energy into mechanical energy and vice versa, attention in this paper is paid mostly to the study of characteristics and parameters of cones and wedges influencing their performance. Cones and wedges inserted between an ultrasonic transducer and the specimen provide the transducer with enhanced capability for point or line contact with the specimen. We study the effect of the dimensions, shape and aperture on the frequency response and the angle of incidence of the wave. Through the testing transducer modeling, some conclusions have been drawn from the analysis, which is useful to as the guideline and criteria for an optimum conical wedge design.

Abstract: The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target filter based on finite set statistics. However, the PHD filter keeps no record of target identities and hence does not produce track-valued estimates of individual targets. To solve this problem, an improved estimate-to-track association method for track continuity is proposed in this paper. Firstly, a multi-step prediction of current target states is made, and then the weighted labels are assigned to them according to the inertia. Secondly, the fuzzy membership degrees of the current state estimates belonging to the tracks are obtained by utilizing the maximum entropy fuzzy clustering. Finally, the tracks are maintained by integrating all this information. Different from the traditional estimate-to-track association method, the proposed algorithm does not update the track information by simply summing the log likelihood ratios between adjacent scans, but take the entire multi-scan information into account by the operations such as weighting and clustering. The simulation results show that the proposed algorithm can maintain target tracks more accurately, even when the targets cross each other, implying strong robustness and excellent performance of track continuity.

Abstract: Using FPGA for general-purpose computation has become a hot research topic in high-performance computing technologies. However, the complexity of design and resource of FPGA make applying a common approach to solve the problem with mixed constraints impossible. Aiming at familiar loop structure of the applications, a design space exploration method based on FPGA hardware constrains is proposed according to the FPGA chip features, which combines the features of the corresponding application to perform loop optimization for reducing the demand of memory. Experimental results show that the method significantly improves the rate of data reuse, reduces the times of external memory access, achieves parallel execution of multiple pipelining, and effectively improves the performance of applications implemented on FPGA.

Abstract: This paper introduces the touch screen driver design based on Linux plays an important role in applications of touch screen. In order to further explore embedded touch screen driver design, and then optimize and improve existing drivers at practice level, this paper accomplished the design of touch screen driver using SPI interface and ADS7843 touch screen chip controller based on Samsung S3C2410s microprocessor. We designed the touch screen hardware interrupt program using the bottom half mechanism of the kernel timer, utilized 16 clock cycles of coordinate conversion sequences to achieve touch point based data acquisition and present the process of coordinate collection. The touch screen driver ran well on the UP-NETARM2410-S platform. The hardware design was verified to be simple and reliable while the corresponding software accomplished touch state detection and touch data conversion efficiently. The touch screen control method is simple, efficient and easy to realize.

Abstract: State fusion problem of linear systems with two channel observations is discussed. A globally optimal recursive algorithm is proposed based on projection formula and innovation analysis. Different linear weighted fusion, the algorithm presented is globally optimal, which is equivalent to centralized Kalman filtering. Moreover, the algorithm is good for real-time demand for innovations from different channels are orthogonal.

Abstract: The advent of GPS technology creates a new high-tech avenue for ocean mapping. This paper mainly discusses the application of GPS-RTK technologies in undersea topographic survey. Taking the project of Yangkou man-made island in Nantong city as an example, discuss the particular application of sea mapping in under-water topographic survey. The main job and work procedure of GPS technologies in under-water topographic survey are introduced. Problems need to be cared during the procedure and how to solve them also are discussed. Feasibility analysis of RTK technologies in undersea topographic survey is also done in this paper.

Abstract: In order to solve the current dynamic OD estimation problems on the background of gradual application of automated vehicle identification facilities, the relationship between dynamic OD estimation and traffic parameters under AVI environment is analyzed. The dynamic OD estimation model basing on Kalman filter algorithm is established. The coefficient matrixes of state equation and observation equation are calibrated dynamically by neural network respectively. The simulation results show that the model has higher estimation accuracy for OD pairs with great flows. The model can be adopted as one of the theoretical models for dynamic OD estimation supporting traffic control and management.

Abstract: Based on two-microphone transfer function method, the measuring method of incident sound power in duct is introduced, The special test equipment is built, and the test and measurement program of incident sound power in duct is written, and effect factors of measurement are analyzed. Results are shown that temperature, flow velocity, microphone spacing deviation and complex reflection coefficient influences less on the program. Transmission loss of perforated tube muffler with no flow is measured using the program, comparison is carried out with results of finite element method, they agrees with well, and with flow sound power of flow regeneration from the muffler is also done, an important foundation is provided for quantitative study on occurring mechanism flow regenerated noise and enhancing attenuation performance of muffler.

Abstract: For the congestion problems with multi-user existing in high-speed networks, a pricing scheme based Nash Q-learning flow controller is proposed. It considers a network with a single service provider, and some non-cooperative users. The pricing scheme is introduced to the design of the reward function in the learning process of Q-learning. Because of the uncertainties and highly time-varying, it is not easy to accurately obtain the complete information for high-speed networks. The Nash Q-learning, which is independent of mathematic model, shows particular superiority. It obtains the Nash Q-values through trial-and-error and interaction with the environment to improve its behavior policy. By means of learning process, the proposed controller can learn to take the best actions to regulate source flow with the features of high quality of service. Simulation results show that the proposed controller can promote the performance of the networks and avoid the occurrence of congestion effectively.

Abstract: An integrated production-inventory-delivery lean supply chain model is discussed. The model is integrated with production, supply and distribution through cost. And the delivery of purchasing and distribution is consolidated. A non-linear programming model with multivariable is proposed. The length of path and the frequency of delivery are regarded as decision-making variables. The optimal delivery path and the length of path are first solved by using improved ant colony optimization algorithm. And the optimal frequency of delivery and the batch of delivery are achieved. Last, the model is validated through an example and the result indicates the model is simple and practical. Moreover it is meaningful for practice.