Applied Mechanics and Materials Vols. 511-512

Abstract: To the problem of text elements outside main content of clicked documents have big negative impact on the precision of query recommendation, this paper proposed a query recommendation method based on document content user focuses on, which fused similarity computation among queries with the filter of text elements outside main content of clicked documents. Experimental result shows that the method proposed by this paper can raise the precision of similarity computation among queries, and then raise the precision of query recommendation.

Abstract: This paper introduces the related theory of sound waves , we collect the data through the acoustic wave sensors of the pipeline fault diagnosis system platform, decompose the signals to five layers by Mallat algorithm and wavelet function db4, compare the normal waves and leakage acoustic signal spectrum, and then get the power spectrum estimation for the decomposed signal at each level, we can see the signals energy feature in different frequency band. Feature extraction method based on wavelet transform can make the category of signal characteristics fully displayed in the different resolution band, it has a good application prospect in the field of acoustic signal processing.

Abstract: In this paper, we analyze the pseudo two-hop distributed consensus algorithm with communication noise. If there is communication noise among agents, the convergence performance of distributed consensus algorithms degrades. Supposing that the communication noises are zero-mean Gaussian white noise, and the noises are irrelevant and independent in time and spatial, we analyze the convergence performance of the pseudo two-hop distributed consensus algorithm with noise, and calculate mean square errors and the upper bound of mean-square error of the pseudo two-hop distributed consensus algorithm. Finally, simulation results are provided to verify these analytical results.

Abstract: Measurement while drilling (MWD) technology uses mud pulse signals in real-time observation bottom of the relevant data, the decoding system on earth will detect and recognize the information received from the shaft bottom. It is one of the core technology of MWD. However, there are all kinds of noise that exsit in the signal channel will create interfere of signal transmission with the date identification error .This article first offer a new way based on the analysis of the Manchester mud pulse signal noise code and attenuation model. At the same time it used NLMS(Normalizod least mean square) adaptive filter algorithm to wipe the pump noise and other interferences .It can more effectively decrease the influence by pump pulse base-value. Due to the features of mud pulse, we apply the waveform identification algorithm to the recognize research after get the data. Finally, field test results showed that the waveform identification algorithm can recognize the mud pulse correctly and the decoding process is easier, higher reliability, lower ber by the field test. All these comply with the requirements of the engineering application.

Abstract: Ultralow frequency vibration tables can easily be imposed external interferences when they work. These interferences result to distortion of the output and can reduce the calibration precision. Closed-loop negative feedback method was put forward to reduce the output distortion of an ultralow frequency vibration table. Firstly, we analyzed its structure and principle. Also the reasons of the output distortion of the system was analyzed. The new system was based on DSP unit. And the system is more flexible, higher running speed and better interference immunity. Experiments show that the distortion of the new system can be effectively improved based on negative feedback method.

Abstract: Data warehouse is a subject-oriented, integrated, stable and time-variant data collection which can be applicable in decision analysis. In a background of university teaching administration, this paper takes as the research object the data accumulated in teaching administration system over the years, primarily probes into the building of data warehouse for employment management and, by using the tool of OLAP, conducts the multi-dimensional analysis on the feedback data on graduate employment provided by the employers, in a hope of supporting the middle-level teaching administrative personnel in universities to make decisions.

Abstract: Air quality has been paid increasingly attention, and air quality evaluation via digital image technology can help people know the air quality conveniently. Visible pollutants can affect the degree of image blurring, so it is possible to evaluate the density of these pollutants using image processing. We adopt a local normalized image contrast and attempt to explore its relationship with the values of PM2.5 and PM10. Experimental results demonstrate the proposed measure is promising.

Abstract: Total variation (TV)-based CT image reconstruction has been shown to be experimentally capable of producing accurate reconstructions from sparse-view data. In this study, an inexact distributed reconstruction algorithm based on TV minimization has been developed. The algorithm is relatively simple as it uses the inexact alternating direction method, which involves linearization and proximal points techniques. The outstanding acceleration factor is achieved as the algorithm distributes the data and computation to individual nodes. Experimental results demonstrate that the proposed method can accelerate the alternating direction total variation minimization (ADTVM) algorithm with very little accuracy loss.

Abstract: Remote sensing image analysis is an important aspect of remote sensing technology and application, but until now a comprehensive mathematical model is still missing for spatial analysis and reasoning. From the mathematical essence, the processing of remote sensing image analysis is to build a transform relationship between the premise and the conclusion of reasoning based on domain knowledge, and which is used to deal with the transformation reasoning. Based on fuzzy set and topology theory, this paper discussed how to build mathematical models of target identification, information extraction, and semantic extraction of remote sensing imagery. By a series of reasoning, a reasoning model based on the topological transformation is proposed, which is used to transform remote sensing image analysis into an uncertainty reasoning of mathematical sciences.

Abstract: Liquefied natural gas (LNG) is obtained by cooling the gas temperature to -162 degree. Problems with the steel cans, the insulation layer or the concrete tank of the LNG tank can lead to changes of the temperature, local temperature decreases, and the safety of the tank is threatening. Through the combination of many sets of infrared thermal imager to monitor the temperature of the LNG storage tank’s sidewall, analyze the heat imagine, establish the corresponding relationship between the locations on the sidewall of the LNG tank and on the heat imagine, determine the position of the temperature point on the tank wall. Infrared thermal imaging technique for the sidewall of LNG storage tank can find out the heat abnormal conditions and fixing the temperature drop area in time, and provide powerful guarantee for the safe storage of the liquefied natural gas.