Key Engineering Materials Vols. 439-440

Abstract: Gyroscope is the core of an inertia system and made by machining process. Machining process imports large residual stress. The residual stress will be released and induces large deformation of gyroscope frame. In this paper, the effects of residual stress on deformation of gyroscope frame were simulated by finite element method. Different stress distribution leads different deformation. Compressive stress can make sample long and tensile stress make sample short. The stress released in deformation process which reduced about 90%.

Abstract: Modernization is the inevitable way for progress of human society, in which the agricultural modernization is an important component. To achieve modernization, including the agricultural one, is a significant strategic objectives for chinese government. The agricultural modernization is a dynamic process, and to establish the modernize index system can help developing the whole process of agricultural modernization into a measurable process, which is beneficial for the nation and government departments at all levels to advance the relatively objective understanding about the status and development trend of agricultural modernization. The paper has developed a set of agricultural modernization index system, and proposed the evaluation method of agricultural modernization level based on this set of index system. To evaluate the agricultural modernization with this method makes the agricultural modernization development throughout the country comparable, which helps reflecting the actual local development level of agricultural modernization, meanwhile, it provides theoretical basis for adjusting agricultural modernization goal in time.

Abstract: This article proposed the improvement BP algorithm which solved the neural network to restrain slow and easy well to fall into the partial minimum the question, through setup time sequence forecast model made the long-term power forecast, and made a comparison with the traditional BP natural network.

Abstract: This paper presents the parameter identification technology of heavy commercial vehicle rollover prediction. In this study, a nonlinear truck model has been established for the rollover threat prediction. In order to achieve valid and representative truck model as close to the target real truck as possible, a set of key parameters are identified from experiment data collected from real truck ground test. At the last, the vehicle prediction model simulation results compared with the experimental results, it is shown that the prediction model can be accurately predicted the rollover dangerous state.

Abstract: In the past few years, there have been tremendous interest in the peer-to-peer(P2P) content delivery. This communication paradigm dramatically increases the traffic over inter-ISP links. In particular, BitTorrent(BT), the most popular P2P application, generates a huge amount of traffic on the Internet. BitTorrent’s performance is limited by the fact that typical internet users have much lower upload bandwidths than download bandwidths. This results in the overall average download speed of a BitTorrent-like file download system to be bottle-necked by the much lower upload capacity. We think about to utilize idle users’ spare upload capacity to largely improve the download speed beyond what can be achieved in a conventional BitTorrent network. In this paper, we design a system that is completely compatible with the already existing clients who conform to the BitTorrent protocol, at the same time, we analyze this system’s steady-state performance and present simulation results.

Abstract: Unstructured peer-to-peer (P2P) systems，due to their excellent support for content lookup and sharing，are creating a large proportion of network traffic in today’s Internet. A P2P system typically involves thousands or millions of live peers in the network. In this paper, we propose and evaluate an efficient searching scheme in unstructured P2P networks. This scheme proposes a local adaptive routing protocol. This routing protocol adopts a simple scheme which driven by query interest among peers. We analyze this scheme’s performance and present simulation results. Our simulation results demonstrated the benefits of the proposed system and show that the approach is able to dynamically group nodes in clusters containing peers with shared interests, at the same time, and organized into a community network.

Abstract: Structured peer-to-peer (P2P) systems are creating a large proportion of network traffic in today’s Internet. Peer-to-peer systems enable access to data spread over an extremely large number of machines. A P2P system typically involves thousands or millions of live peers in the network. Multi-dimensional data indexing has received much attention in a centralized database. In this paper, we propose and evaluate a multi-dimensional searching scheme in structured P2P networks. We present the design and implementation of a peer-to-peer index service for high dimensional data that is capable of handling complex queries. We design a VibIndex scheme in structured P2P overlay networks. We analyze this scheme’s performance and present simulation results. Our simulation results demonstrated the benefits of the proposed system and show that the approach is able to search efficiently.

Abstract: This paper focuses on the structural optimization of chemical sensor support for food safety detection. The mechanical characteristic of chemical sensor support is influenced greatly by its structural parameters. Aiming at improving dynamic stiffness of the support, the modal analysis is implemented with the dynamic theory and the finite element analysis. And a group of rational structure parameters are determined through the optimum calculation. The validity simulation of the optimization is verified by the analyses of the random vibration and harmonic response. The results demonstrate that the performance of the support of the chemical sensor applied for the food detection is enhanced greatly by the presented optimization method here.

Abstract: With the three-dimensional computational fluid dynamics method, the airflow effects over the huge telescope assemble is investigated in this article. The distributing of velocity field and natural convection are studied by modeling and simulating the turbulent airflow of the huge telescope. Numerical simulations show the best observation direction is the 90o angle between the main optics axis and the horizontal line in which the air velocity distribution is the least. And the air temperature distribution and uniformity around the telescope are also provided by simulation.

Abstract: A hybrid algorithm based on mean coding and vector quantization is presented in this paper. The smooth image block is coded with the mean coding algorithm, which can reduce the vector quantization (VQ) search computation and improve the compression ratio effectively, and this method is called the basic blended algorithm (BBA). On this base, an adaptive partitioned algorithm (APA) algorithm based on 16×16 pixels image block is proposed, the optional image block sizes are 16×8, 8×16, 8×8, 8×4, 4×8, 4×4 pixels, the image is coded adaptively at different levels. The size of mean coding is chosen adaptively according to the size of the smooth image block, the Not-smooth 4×4 pixels image block is coded by VQ. In addition, the improved APA (IAPA) is also given in this paper. Simulations show that the APA and IAPA proposed in this paper are proven to have great performance for different kinds of images, especially significant for those have large areas of static background and little details. Compared with BBA, the compression ratio of APA and IAPA can be improved by 416% and 512%, the PSNR of APA and IAPA is reduced only 2.4% and 3.6%, the complexity can be reduced significantly, which is of advantage to hardware implementation.