Applied Mechanics and Materials Vols. 135-136

Abstract: A method of power adaptive control for hydraulic motor graders is provided, including the dynamic regulation methods of pump and motor and realization algorithms related. The simulation models of hydraulic transmission system and the control system are established in AMESim and Simulink respectively. By using these two softwares, the models are co-simulated. The co-simulation results verify the feasibility and effectiveness of the control system.

Abstract: In order to explore railway freight transport potential, release productivity and alter transport developing mode, this paper proposes railway wagon-loading yard arrangement planning according to the innovation theory of railway organization and network planning. Fuzzy comprehensive evaluation system was established with reality analyze. After analyzing 1,172 loading yards, we developed the decision support system based on VB. The system provides references and methods for the yards to achieve logistics and transit transport. The Suggestions and further research are mentioned eventually.

Abstract: In order to make the Web services, web sites in Java more powerful and flexible, building unified web applications is vital important. By introducing a new style─Representational State Transfer (REST), this paper studied the Java RESTful frameworks and the ways to develop Restful Web Service in Java. The RESTful frameworks in Java can effectively simplify the web development in many ways.

Abstract: With the rapid development of the urbanization, the problem of city transportation has been becoming the same issue to each big city in China. As the converge points of urban traffic, the branch junctions are playing important role in the road net and traffic flow. It is true that traditional PID control algorithm is widely used in various control systems. Because its principle is simple and easy to build and has no error in the steady state, etc. However, it does not have a good adaptability towards the change of parameters. It is inferior towards interference, etc. According to the above situation, a adaptive Fuzzy-PID control algorithm is proposed which has returned the characters of regular PID control algorithm. The fuzzy control algorithm is used to realize the on-line regulating relative PID parameters. The simulation analysis indicates that the presented method is effective to improve the main road control.

Abstract: Aimed at the people localization in the underground mine, the bounding-inbox localization algorithm of wireless sensor networks based on RSSI is presented in this paper, which combines the merits of range-based and range-free localization methods. And, signal strength information between fixed anchor nodes and unknown ones is taken as the weights of bounding-inbox algorithm to calculate. The result of simulating experiment in underground mine environment proves that this algorithm is of less computing cost and can improve the localization accuracy.

Abstract: Doppler shift decreases the estimation accuracy of carrier frequency and may result in divergent estimation. It thus degrades the performance of orthogonal frequency division multiplexing (OFDM) underwater acoustic (UWA) communication system. In this paper, the two-step Doppler shift mitigation scheme[4] was adopted to mitigate the Doppler effect. The innovation lied in the second step in which an enhanced carrier frequency offset (CFO) two-time estimation approach on basis of the pilot was proposed to improve the Doppler shift mitigation scheme. In addition, the new Doppler shift mitigation scheme with the proposed approach was implemented in the OFDM communication system under the simulated multipath-spread channel environment. The experiment results show that the new scheme is able to improve the performance of OFDM UWA communication significantly.

Abstract: Non-uniformity of the asphalt pavement is one of most important reason for early disease, control of non-uniformity in the production process of asphalt pavement is an important measure to ensure that quality and service life of pavement. Nuclear density gauge (PQI) can be non-destructive, rapid detection of asphalt pavement density. This paper give a research and application on the PQI calibration, testing frequency, the control parameters and evaluation index, and proposes a control method of non-uniformity in asphalt pavement construction with PQI. Asphalt pavement quality control in construction process can use this method. It is important to improve the stability of asphalt pavement quality and reduce the incidence of disease, and also has a certain reference value for establishing the quality control and quality assurance systems.

Abstract: It is known to all that the performance of Para-virtualization virtualization machine is much better than full virtualization machine's. However, the full virtualization machine has advantage that it need not require modify the operating system kernel. Therefore we worked to improve the performance of network in the full virtualization environment. This paper provide a method to improve Xen network virtualization performance and so we could be both using the full virtualization machine without change the operating system and improve its performance to a high level.

Abstract: Semantic representation problems of computer programming questions are very common in computer contests. Ontology-based method can help to express the metadata and formalize the computer programming questions. Therefore, this method can make people who are tested more clearly to the semantics. This work can provide basis for the future research.

Abstract: LTE is a long term evolution scheme of 3GPP, as a using extensively communication standards, it has higher data rate and higher quality. Channel estimation plays a quite important role in the LTE system which requires the high data rate and quality. In the article, based on the analysis of the LS and MMSE algorithms of the LTE system, a advised algorithm is adopted. The pilot signal is processed before the channel estimation by reducing noise in time domain. The simulation results demonstrate that the advised algorithm is a preferable choice in estimation performance, simultaneously; the advised has obviously reduced the algorithm complexity.