Applied Mechanics and Materials Vol. 525

Abstract: The mud pulse signal extracting in MWD(Measurement while drilling) was a core technology in the oil drilling developing process. Determining how to accurately define the mud pulse signal starting time was a key issue affecting the decoding accuracy. This paper analyzed the transmission format of down-hole datum and transmission characteristics of mud pulse signal, using a wavelet multi-scale and related de-noising algorithm to extract mud pulse signal. On this basis, according to the characteristics of the underground encoded synchronization signal, It proposed an algorithm based on equal segmentations within a signal period to define the mud pulse signal starting time .The field tests show that the algorithm can accurately define the mud pulse signal starting time and can effectively improve the decoding accuracy and meet the requirements of engineering applications.

Abstract: In recent years, the building information modeling (BIM) has gained rapid acceptance in the building industry in China. In the near future, BIM will be able to provide a three-dimensional product model for the full life cycle management to the related parties of the construction industry. This article firstly expounds the significance of this study, then it describes the development and application of BIM in china and abroad. Finally, this article mainly introduces the barriers of promoting the use of BIM in our country and advices, it provides an important reference value to promote BIMs broader and deeper application in the Chinese construction industry.

Abstract: LBL(Long Baseline) positioning provides an important positioning and navigation method for AUV(Autonomous Underwater Vehicle)’s underwater task. Due to the complex underwater acoustic channel, and its poor anti-interference ability, a new feedback Kalman fiter algorithm was present in this paper. By combining travel time information with position information, the state of AUV was estimated accurately. By analyzing experimental results, it showed that the LBL positioning accuracy was improved, and the algorithm ensured AUV complete its autonomous navigation with high precision.

Abstract: Acousto-optical-Modulator (AOM)'S characteristics of shift frequency can be used to change the frequency of laser, the performance of AOM will improve directly by a high stability driving signal source. The paper presents a design of high stability of DDS signal source for laser frequency shift, the signal source output frequency range of 50MHz-400MHz. Using atomic frequency standard and external frequency multiplier as the reference source of DDS to make its frequency stability reaches , using sub-octave filter to get a high output signal spectral purity.

Abstract: As the complexity and reliability requirements of software projects increase constantly, software testing is becoming more and more prominent and important in software engineering. Testing management system is the basis of constructing software testing management system. It regulates software testing processes, and ensures the entire testing process is under control. Based on the Django framework, this paper design and implement a test management system based on B/S architecture. It can operate as a common platform for software testing management, and reduce the cost and cycle of software testing, guarantee the quality and efficiency of software testing.

Abstract: Contrast pyramid algorithm is put forward in this paper. The human visual system is sensitive to contrast information of image, so contrast pyramid algorithm would outstanding the contrast of image. The algorithm consists of creation process of Gauss Pyramid, the process of creating contrast Pyramid and reconstruction process of clear image. Simulation by MATLAB was completed in multi-focus image, multi-modality image and color image. Objective evaluation index such as mean, standard deviation, entropy and average gradient was calculated Simulation results and index show that the contrast pyramid algorithm has advantage of projecting the contrast of image, especially in color image fusion.

Abstract: Image fusion algorithm based on gradient pyramid is one of the multi-scale, multi-resolution decomposition algorithms. Original image was decomposed into Gauss pyramid, after that, gradient decomposition was completed on each layer in four directions, and fusion effect was evaluated by taking using of entropy, average gradient, mean and standard deviation. Simulation results show that gradient pyramid algorithm is effective to multi-focus image and color image.

Abstract: Threshold-based segmentation algorithms are introduced and simulated. In order to evaluate the performance of various threshold segmentation algorithms, the quantitative experimental criterions are introduced and applied. And through large experiments by using MATLAB, threshold segmentation algorithms are evaluate with uniformity measure (UM), shape measure (SM) and gray-level contrast (GC). The effect of image segmentation is described by using the average value of three experimental criterions (UM, SM and GC).

Abstract: The block-division based segmentation algorithm is raised in this paper, which overcomes the shortcomings of the whole and single threshold method. Each block is processed with two-value segmentation algorithm, and finally, all blocks are combined for image recovery. In order to evaluate the performance of block-division based segmentation algorithms, some experiments are carried out by using Matlab 7.0. Experimental results show that block-division based segmentation algorithms can perform well and get a better result than the other threshold segmentation algorithms.

Abstract: In the present under the uncertain and change prevailing environment atmospheres influence, competitive intelligence without well-grounded methodologies and system for scouting and monitoring dynamic intelligence has become impossible. Dynamic intelligence process refers to continuous process of gathering, analyzing and reporting information about specified topics to users. The dynamic intelligence process should always be anchored to four key factors (IndustryTechnologyKey Person and Customer) within which information will be used. Whats more, we also need to know how to set up systems and models to identify and analyze competitors first of all.