Applied Mechanics and Materials Vols. 427-429

Abstract: To detect week signal of underwater magnetic fields, we designed a negentropy maximization blind source separation algorithm based on the stochastic gradient descent algorithm by bring in a penalty factor. The simulation study demonstrates that the new algorithm is effective to separate the mixed-signal with high precision, to decrease the iterative calculation and to enhance the convergence rate.

Abstract: The well formed formulas (wffs) in classical formal system of propositional calculus (CPC) are only some formal symbols, whose meanings are given by an interpretation. A probabilistic logic system, based on a probabilistic space, is an event semantics for CPC, in which set operations are the semantic interpretations for connectives, event functions are the semantic interpretations for wffs, the event (set) inclusion is the semantic interpretation for tautological implication, and the event equality = is the semantic interpretation for tautological equivalence. CPC is applicable to probabilistic propositions completely. Event calculus instead of truth value (probability) calculus can be performed in CPC because there arent truth value functions (operators) to interpret all connectives correctly.

Abstract: The methods for determining optimal policies are core problems in the standard secretary problem. The optimal policies are based on the hypothesis of complete rationality. However, some experimental researches showed that decision makers in reality often stopped searching earlier. In this paper, some assumptions of the standard secretary problem are weakened and a satisficing policy based on the hypothesis of bounded rationality is proposed to describe the choice behavior of a decision maker. Moreover, the possibility degree of the decision-maker to choose the satisfactory item is calculated.

Abstract: This paper studied the effect of several parameters on pitch perception of unresolved harmonics by measuring fundamental frequency difference limens. The parameters included roving fundamental frequency or not, type of background noise, and cutoff frequency of lowpass pink noise. Results found that performance was significantly worse when the fundamental frequency was roved than the constant case, lowpass pink noise had similar ability to mask combination tones as threshold equalizing noise, and that combination tones could be masked if the cutoff frequency of the lowpass pink noise was not lower than the frequency of the tenth harmonic. This paper proposed a set of appropriate parameters for experiments of pitch perception, which suggested that roving fundamental frequency, using threshold equalizing noise with the level of about 8-13 dB below the level per component of the stimuli, or using lowpass pink noise with the cutoff frequency not lower than the frequency of the tenth harmonic, can achieve effective performance for pitch perception.

Abstract: The aim is to improve the convergence of the algorithm, and increase the population diversity. Adaptively particles of groups fallen into local optimum is adjusted in order to realize global optimal. by judging groups spatial location of concentration and fitness variance. At the same time, the global factors are adjusted dynamically with the action of the current particle fitness. Four typical function optimization problems are drawn into simulation experiment. The results show that the improved particle swarm optimization algorithm is convergent, robust and accurate.

Abstract: During camera calibration, the calibration pattern image is always skew. This brings much difficult to feature points sorting, which affects calibration accuracy. In this study, a rotation based sorting method is proposed. First, detect the skew angle accurately; then, transform the original coordinates to the rotated coordinates and establish the mapping relation; then, sort the rotated coordinates; finally, sort the original coordinates using the mapping relation. To verify the feasibility of this method, an experiment is carried out. The result shows that the rotation based sorting method can sort the feature points accurately at different skew angles. Its accuracy makes this method suitable for high accurate camera calibration.

Abstract: To deal with the problem of premature convergence of the traditional K-means algorithm, a novel K-means cluster method based on the enhanced Particle Swarm Optimization (PSO) algorithm is presented. The algorithm can be had in the course of the introduction of adaptive Gaussian global extremum mutation operator, enhancing particle diversity of the population, thereby increasing the ability of global optimization algorithm. The experimental results show the proposed method can not only effectively solve the premature convergence problem, but also significantly speed up the convergence.

Abstract: Uncooled infrared imaging system has been increasingly applied in both the national defense and various fields of national economy. Such popularity is attributed to many of its advantages, including small size, light weight, low energy-consumption and superior portability. However, as limited by the structure and the material of infrared detector and the manufacturing techniques, infrared images are plagued with low resolution and poor image quality. This paper mainly studies the uncooled infrared image processing based on the gray levels partition processing, gray levels stretching and histogram modification, it aims to enhance the visual effect of infrared image.

Abstract: In recent years , the research of TIN construction is mature at home and broad, but to the ordinary technical workers, its still hard for them to realize in practice. This paper introduces a method which rely on the help of MATLAB language to realize the TIN building and application.At last, the paper explained the well application of the model in waters calculation.

Abstract: In this paper, through the surface of polynomial fitting precision analysis, obtains fitting after converting precision for normal height is mainly affected by the rate of change vertical deflection and higher order termsalso influenced by local terrain correction. The undulating topography is deduced and the calculation formula of cause height anomaly, this method is applicable to the complex terrain of area, will dividend increase formula one of the smaller constant, the calculating process of the intermediate results are returning to normal range, effectively avoid the central region of the singular integral. In the terrain change large region, attend to the influence of terrain correction, the surface fitting method for elevation conversion, can effective improve GPS elevation fitting the precision of the conversion.