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Chen Z.,Nanjing University of Posts and Telecommunications | Chen Z.,Nanjing University | Chen Z.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology | Li S.,Nanjing University of Posts and Telecommunications | And 3 more authors.
International Review on Computers and Software

In order to improve energy efficiency, the bacterial foraging optimization algorithm (OBFOA) is applied into the routing strategy for wireless sensor networks. The proposed strategy makes proper improvements on bacteria's foraging operation to improve the performance of the algorithm, such as the adaptive step strategy in the swimming operation and the comprehensive selection mechanism in the tumbling operation. OBFOA builds optimized data transfer paths in wireless sensor networks through the processes of chemotaxis, global quorum sensing mechanisms, reproduction and elimination-dispersal. Simulation results show that the proposed strategy can balance the energy consumption of nodes effectively and prolong the overall network lifetime. © 2012 Praise Worthy Prize S.r.l. - All rights reserved. Source

Wang J.-M.,Tianjin Polytechnic University | Wang X.,Tianjin Polytechnic University | Wang S.-B.,Tianjin Polytechnic University | Li S.-X.,Tianjin Navigation Instruments Research Institute | Leng Y.,Suzhou Entry Exit Inspection and Quarantine Bureau
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology

Navigation is a key technology for autonomous robots, which makes them movable in an unknown environment. To tackle the difficulty of building indoor navigation map for inertial navigation systems, a new map building method for inertial/visual navigation is proposed. By limiting robot's movement within the floor areas, the global navigation map is generated from a bird-view image. An algorithm of automatic floor segmentation is proposed, which employs principal component analysis to implement dimension reduction for local color features and adopts clustering analysis to realize floor segmentation automatically. Finally, an indoor bird-view image database is built to evaluate the algorithm. The algorithm gets the worst performance, 75% averaged accurate segmentation rate, on the fourth group images because illumination reflection is found in the images. Average accurate segmentation rates on other groups are around 85%. Thus, the preprocessing algorithms, such as illumination refection detection, can help to improve the performance of the algorithm. Source

Shi J.,Nanjing University of Posts and Telecommunications | Chen Z.,Nanjing University of Posts and Telecommunications | Chen Z.,Nanjing University | Chen Z.,HIGH-TECH | And 4 more authors.
Chinese Journal of Sensors and Actuators

Well-designed network topology control method can reduce energy consumption and achieve efficient use of energy networks. The evolution rules of the wireless sensor network system topology are established, which are on the basis of two-dimensional cellular automata and consider nodes' random distribution and the work/sleep/disable tri-state. The best control parameters of the evolution rules have been studied in setting the initial conditions, and simulation using those parameters shows that optimized cellular automata based network topology control extends the network life in ensuring coverage and connectivity. Source

Wang J.-M.,Tianjin Polytechnic University | Yan Z.-J.,Tianjin Polytechnic University | Duan X.-J.,Tianjin Polytechnic University | Dou R.-Z.,China Automotive Technology and Research Center | Leng Y.,Suzhou Entry Exit Inspection and Quarantine Bureau
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering

Ego-motion estimation, which can retrieve motion information of a camera by analyzing images taken by the camera at different positions, has played an important role in vision navigation. Mathematically, perfect theoretical foundation of ego-motion estimation has been developed. However, noise is always found in images, which could depress the performance of ego-motion algorithms severely. So, at present the main problem of ego-motion estimation is how to develop robust algorithms against noise in images. This paper focused on the problems of robustness of ego-motion estimation algorithms, and the main idea was to improve robustness by adopting multiple methods for ego-motion estimation and find the optimal result in them. Firstly, SIFT was used to find correspondence point pairs between two images, and a scheme to refine the correspondence point pairs was proposed. Multiple methods were adopted to estimate the fundamental matrix and the optimal estimation was found by a rule deduced from imaging process. Finally, the algorithm was testified on both simulated data and real images, and the experimental results show the feasibility for improving robustness against noise. Source

Ming Z.,Tianjin Polytechnic University | Jianming W.,Tianjin Polytechnic University | Ling D.,Tianjin Polytechnic University | Yi Z.,Tianjin Polytechnic University | And 2 more authors.
Proceedings - 2011 International Symposium on Computer Science and Society, ISCCS 2011

Resolvers are extensively used in applications that demand instantaneous, accurate and high-resolution information angular position or speed. A resolver's analog outputs have been modulated by angular position and an R/D converter is always adopted to recover the angular position in digital form. With the rapid growth of micro-processor technology, more and more attention has been focused on software based R/D conversion methods because of their merits, such as saving in cost, weight and size. In practical applications, noise is often unavoidable and might cause severely negative effect on results of software based R/D conversion schemes. To tackle the problem, a new R/D conversion method designed in frequency domain is presented in the paper. Firstly, a new complex signal is constructed by taking the cosine output as the real part and the sine output as the imaginary part. After transforming the complex signal into frequency domain, only the components at the carrier frequency are utilized to calculate the angular position. Thus, the negative effect of noise, whose energy is located out of the band of the carrier frequency, can be removed. In the simulation experiments, dc drift, white noise and pulse disturbance are utilized to evaluate the performance of R/D conversion algorithms, and the experimental results show the frequency domain based method is favorably robust to all the three types of noise. © 2011 IEEE. Source

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