Applied Mechanics and Materials Vols. 263-266

Abstract: The designed weighing pressure sensor can adapt to the coal mine underground complex environment. The sensor has the characteristics of stimulating the vibration quickly, frequency output stable, corrosion-resisting, easy installation and so on. The design on the structure of exciter and sensor has been introduced in detail. Calibrations of the sensor and error analyses have also been conducted as well as the theoretical formula.

Abstract: Wireless sensor networks (WSNs) lifetime for large-scale surveillance systems is defined as the time span that all targets can be covered. How to manage the combination of the sensor nodes efficiently to prolong the whole network’s lifetime while insuring the network reliability, it is one of the most important problems to research in WSNs. An effective optimization framework is then proposed, where genetic algorithm and clonal selection algorithm are hybridized to enhance the searching ability. Our goal can be described as minimizing the number of active nodes and the scheduling cost, thus reducing the overall energy consumption to prolong the whole network’s lifetime with certain coverage rate insured. We compare the proposed algorithm with different clustering methods used in the WSNs. The simulation results show that the proposed algorithm has higher efficiency and can achieve better network lifetime and data delivery at the base station.

Abstract: This paper introduces a monitoring system for health surveillance with the modern wireless communication.On the basis of predecessors' work, a remote heath monitoring system is designed based on Zigbee and human-computer interacting technology, which uses real-time monitoring in the field of disease prevention and rehabilitation. Every node is introduced and the results show that this system overcomes short distance and inconvenience of the state-of-the-art systems.

Abstract: Multispectral remote sensing images are used as research objects for different band images are highly complementary. Pixel is the basic element for image classification. Spectral information and two order invariant moments are proposed to describe pixel characteristics. The self-organizing feature map neural network is used to realize an unsupervised classification. A fringe area of Qingdao is studied and its classification map is obtained using this method. Experimental results show that the classification accuracy is satisfactory by the proposed method.

Abstract: Multi beam sonar needs complex data processing lying on human intervention to get accurate depth contour and low accuracy in sonar image which prevent its popular use in surveying seafloor targets. To survey seafloor target in different depth by GeoSwath, this article presents survey parameter setting method such as ping length, ship velocity to increase points over targets, navigation line parallel to heading of target during survey, adopting along track filter to depth data processing and using TVG control over amplitude data to get accurate depth grid and sonar image of seafloor target. Finally, the way is used to measure the artificial object in harbor and two ship wrecks at sea, which improve GeoSwath survey capability with compound detection and is helpful for make precise map for waterway. Also this work is helpful to achieve detecting seafloor objects fast, accurately, effectively in underwater large scale area during salvation and rescue task.

Abstract: Aiming at the character of high bit error rate and energy constraints on WSN, this paper proposed an adaptive error control scheme based on link quality indicator(LQI). The PHY specification of IEEE802.15.4 provided accurate measurement of channel quality for WSN, according to the quantitative relationship between LQI and bit error rate, this paper divided the channel quality into eight levels non-uniformly, furthermore, eight different BCH code were chosen correspondingly. The motes choose optimal BCH code as its error correction scheme in real time. Experimental results show the scheme is high in energy efficiency, meanwhile, drops the error probability effectively.

Abstract: Wireless sensor networks have been widely used in many areas, such as earthquake monitoring, building structure monitoring, and military surveillance. In this work, we focus on the wireless sensor network deployed in the battlefield, using random key predistribution scheme. Based on the node cloning attack, we proposed a new attack scheme, called compromised key redistribution attack, and discussed related attack scenarios. Furthermore, we have exposed that, when the overlapping factor of compromised key set is larger than 0.05, it is almost 90% that the number of distinct compromised keys is 10.5% of the original key pool. This result helps the adversary estimate the approximated size of original key pool by calculating the overlapping factor, thus calculate the probability that malicious nodes successfully establish malicious connections with legitimate nodes.

Abstract: Energy efficiency is the primary consideration of the design of error control protocol of WSN and energy efficiency analysis is the key point of the present related literature research. However, while emphasizes are on the theoretical analysis and experiments are simulated by advanced programming language such as Matlab、C++ and so on, definitions of some restrictive or operation systems on hardware side of sensor nodes in practical usage are neglected, which lead to the inaccurate conclusion of the error control energy efficiency analysis. In this paper, samples of package-loss and error package and distribution of error codes in error packages are obtained through experiment statistics of a large amount of entity nodes and energy efficiency analysis and comparison of Error Control Techniques of WSN are conducted based on error characteristics.

Abstract: To solve the beacon collision problem in IEEE 802.15.4/ZigBee cluster-tree Wireless Sensor Networks, we proposed a Sequential Beacon Scheduling (SBS) mechanism. In this mechanism, the Cluster Headers (CHs) choose the beacon transmission time in a certain order. The CH which finishes the sequence chosen sends out control frame to inform other CHs in its interference range. The simulation results indicate that SBS general has better delivery ratio, latency, and throughput than three other beacon scheduling mechanisms.

Abstract: Three technologies of insulator online monitoring based on optic fiber sensors is described in proposed paper, including optic fiber sensor salt density technology, optical fiber composite insulator monitoring technology and optical sensor insulator surface electric field detection technology. According to measuring insulator surface ESDD, the internal stress and the temperature distribution of the composite insulators and insulator surface electric field values. these technology can monitor the operation performance of insulator. These techniques that improve the existing insulators monitoring methods has a strong innovative and practical application prospects.