Abstract: In allusion to the problem of quick search based on multi-source GIS data when studying render of GIS data, the author points out one standard map index mechanism. Using this index, we can quickly get right map data format, right map resolving power and right maps in the visible scope, and we improve the speed of map rendering.
Abstract: Compared with the single carrier systems, orthogonal frequency division multiplexing (OFDM) has many advantages of higher bandwidth efficiency and stronger anti-multi-path ability. However, OFDM technology also has some disadvantages, including the multi-carrier synchronization and higher peak-to-average power ratio. In order to solve the higher peak-to-average power ratio problem, this article combines the double-level optimal search method and Kwon suboptimal method, proposes a threshold-based double-level optimal search algorithm. The method is an improved PTS algorithm and is a linear process. The simulation proves that, with the same optimization grouping parameters and auxiliary information, the new algorithm with a reasonable threshold, which has a smaller loss of reducing PAPR performance, greatly reduces the system complexity.
Abstract: This paper researched the cutting algorithm on the basis of the stratigraphic Tin model. Different from the traditional grid cutting method which was a single plane cut, the paper designed a polygon prisms cutting method for simulating geological boundary and mining boundary by the interactive analysis of the stratum model. This method improved on partitioning the triangle nets and reconstructing the stratum, which was able to realize cutting stratigraphic with the arbitrary polygonal prisms. Finally, the test result showed the cut graphics by the method of polygon prisms cutting stratum model in OpenGL 3d graphics library.
Abstract: Abstract. Due to the different levels of economic development and employment policies,the unemployment problem is quite different in different regions of China.How to correctly evaluate the unemployment situation in different areas is the objective reality our country must take seriously in the times of economic transition. 30 provinces and Autonomous regions are used as clustering objects. The unemployment rates from various years are chosen as clustering indexes and whitening weight functions from corresponding indexes are defined. Meanwhile, clustering models of the unemployment assessment are provided and corresponding algorithms are compiled. 30 regions are divided into 3 groups by the unemployment rates: low,medium, and high. The conclusion from our research provided a systematic, objective and accurate evaluation of unemployment in various regions, it may has some reference value for solving China’s unemployment problems.
Abstract: Hand gesture provides an attractive alternative to cumbersome interface devices for human computer interface. Many hand gesture recognition methods using visual analysis have been proposed. In our research, we exploit multiple cues including divergence features, vorticity features and hand motion direction vector. Divergence and vorticity are derived from the optical flow for hand gesture recognition in videos. Then these features are computed by principal component analysis method. The hand tracking algorithm finds the hand centroids for every frame, computes hand motion direction vector. At last, we introduced dynamic time warping method to verify the robustness of our features. Those experimental results demonstrate that the proposed approach yields a satisfactory recognition rate.
Abstract: The background noise influences the face image recognition greatly. It is crucial to remove the noise signals prior to the face image recognition processing. For this purpose, the wavelet de-noising technology has combined with the kernel principal component analysis (KPCA) to identify face images in this paper. The wavelet de-noising technology was firstly used to remove the noise signals. Then the KPCA was employed to extract useful principal components for the face image recognition. By doing so, the dimensionality of the feature space can be reduced effectively and hence the performance of the face image recognition can be enhanced. Lastly, a support vector machine (SVM) classifier was used to recognize the face images. Experimental tests have been conducted to validate and evaluate the proposed method for the face image recognition. The analysis results have showed high performance of the newly proposed method for face image identification.
Abstract: During the frame optimization design, according to fuzzy integrated evaluation theory, fuzzy mathematical models of intensity coefficient and mass coefficient and intensity-mass ratio coefficient of dump truck frame were established. Based on those, in terms of Sugeno fuzzy discursion method, fuzzy discursion model about frame intensity-mass relationship rationality was established, too. Through checkout of three dump truck frames of 170t and 85t and 42t, validation results were the same as the fact. So, it was concluded that the fuzzy integrated evaluation model and the fuzzy discursion model gave helpful guidance on frame designing work.
Abstract: Ball curve； curve design； shape parameter Abstract. Ball curve is found similar to Bézier curve，also it has a good property of shape preserving，and in some respects，it has better properties than the Bézier curve. Therefore, In the shape design，Ball curve is paid more and more attention, it has a wide application. By introducing the concept of weights in NURBS curve into a blending technique, the paper extends the representation of the cubic Ball curve. The generalized cubic Ball curve is denoted as α extension cubic Ball curve, whose shape-control capability is shown to be much better than that of Ball curve. The representation and properties of the extension curve are studied. The curve is easy and intuitive to reshape by varying the parameters; so it is useful in some applications of CAD/CAM.
Abstract: In order to investigate the bending and mixing characteristics in a vertical jet issuing into a swirling cross-flow, large eddy simulation method was employed to simulate the flow field of a jet in swirling cross-flow. Several jet to cross-flow velocity ratios (r=15, 30, 60) were investigated. The numerical results were compared to the experimental data measured from a phase tunable laser and CCD system. The Reynolds number Re based on the characteristic length of the cross-flow tunnel and the jet velocity lies between 22,537 and 90,146. Numerical results showed that the penetration depth of the vertical jet maintains nearly unchanged when the jet to cross-flow velocity ratio is large enough (r>30), which agreed well with the experimental data and was different from the flow field of jet in straight cross-flow. On the other hand, the case of r=60 obtained largest spread width, and the spread width maintains relatively large in a large penetration zone, which is consist with the experimental finding.
Abstract: Through methods, such as microscope analysis, metallographic examination, the crack located nearby the fusion line between tee joint and outlet steam pipe of subcritical power station boiler final superheater header is reheat crack (the main crack occurred in the heat affected zone and extended along the fusion line and grain boundary in HAZ. There are many small cracks paralleling with main crack). The base metal material (12Cr1MoV) and excessive welding residual stress are the primary inducement of crack. In repair crack, the measures of reducing residual stress, such as lower welding heat input, reducing thickness of welding layer, hammer blowing, assigning reasonably heat treatment power ,lengthening holding time and so on, were taken. The welding repair succeeded greatly.