The sensitivity of power to relative cavity loss of the intra-cavity sensor based on erbium-doped fiber laser is investigated. Theoretical analysis and simulation show that the coupling ratio of coupler and the pump p...
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The sensitivity of power to relative cavity loss of the intra-cavity sensor based on erbium-doped fiber laser is investigated. Theoretical analysis and simulation show that the coupling ratio of coupler and the pump power have a great effect on sensitivity of ring intra-cavity sensor. And we have experimentally found that the sensitivity can be significantly enhanced as pump power approaches the threshold and the coupling ratio is higher.
This paper considers intelligent diagnosis of structural cracks emanating from rows of rivet holes in thin metallic plates using active sensing network. Lamb waves are generated using actuators and propagate across th...
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This paper considers intelligent diagnosis of structural cracks emanating from rows of rivet holes in thin metallic plates using active sensing network. Lamb waves are generated using actuators and propagate across the plates and received by sensors. We extract an effective feature called energy ratio change from time domain signals using wavelet transform. Then we develop neural networks using this feature to diagnose health condition. The sensing network is optimized by developing a mixed integer programming model. The results show that our method can effectively detect cracks and determine their locations, and the number of sensors of the sensing network can be significantly reduced while keeping high diagnostic accuracy. Important insights are also obtained such as in which area the sensing network has the weakest diagnostic capability.
This paper describes a ZigBee based wireless system to assists traffic flow on arterial urban roads. Real-time simulation in laboratory environment is conducted to determine the traffic throughput to avoid possible co...
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ISBN:
(纸本)9781467346214
This paper describes a ZigBee based wireless system to assists traffic flow on arterial urban roads. Real-time simulation in laboratory environment is conducted to determine the traffic throughput to avoid possible congestions or ease existing congestions. Random numbers are generated to mimic approaching traffic, and this information is shared by a ZigBee-based real-time wirelessly network. Wireless nodes are connected to different PLCs representing different traffic lights in a cluster. Once the information is shared the timing and sequencing decisions are taken collectively in a synchronized manner. In this paper, the information is displayed on SCADA connected to each PLC for viewing the characteristics of continuous vehicular flow. It is found that the topology of the network can play an important role in the throughput of data, which may be critical in safety critical operations such as the control of traffic lights. This paper aims to highlight some of the possible effects of dataflow flow and time-delays faced by modern intelligent control of traffic lights.
Underwater sensor network nodes typically detect and communicate through the propagation of acoustic waves. To localize an unknown noise-source with an underwater sensor network, one can combine bearing estimates from...
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ISBN:
(纸本)9781849197748
Underwater sensor network nodes typically detect and communicate through the propagation of acoustic waves. To localize an unknown noise-source with an underwater sensor network, one can combine bearing estimates from various sensors while taking into account their respective position. As the battery life of each underwater sensor dictates the overall network endurance, each sensor must make sense of the various propagated signals and derive a likely bearing estimate to pass to neighbouring nodes while consuming as little power as possible. Most publications presenting distributed noisesource localization approaches performed by underwater sensornetworks are inadequate in that their assumptions do not usually apply to an underwater setting and only use simulated scenarios. Unlike these publications, the proposed distributed noise-source localization scheme is tailored to and tested with real underwater acoustic detections. In particular, we present simple computational schemes for the sake of extending the operational life of the overall network. Those schemes monitor and estimate the main bearing characteristics while simplifying their representation. In general, the proposed techniques outperform the traditional approach of selecting bearings based on an intensity-only threshold.
Applications of wireless sensornetworks (WSN) in freeway information monitoring are rapidly expanded. The freeway optimal sensing coverage and efficient energy consumption problems are the fundamental requirement for...
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Wireless platforms are becoming less expensive and more powerful, enabling the promise of widespread use, everything from health monitoring to military sensing. In large scale applications like military surveillance, ...
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ISBN:
(纸本)9781479922994
Wireless platforms are becoming less expensive and more powerful, enabling the promise of widespread use, everything from health monitoring to military sensing. In large scale applications like military surveillance, sensing coverage is essential for target detection and optimization of power consumption is important for lifetime extension of the network. Coverage and long lifetime network are two important factors and challenges for sensornetworks. In this paper, we propose a new scheme, named as BECG, which remains the best coverage of the sensing area and energy balanced scheduling for all sensors. It allows nodes to determine when they can switch to sleep mode during operation. The energy efficiency of the proposed scheme is shown by intelligent decisions making. Each node in the network takes decision to turn on or turn off in a distributed manner that results a set of small number of active nodes throughout the lifetime of the network and covers sensing area of interest for target detection. It reduces redundancy, power consumption and increase the lifetime of a network. At first we applied our algorithm for a random topology and then we evaluate the performance of the network by simulation.
This research work presents a new model in Wireless sensor Network in which data aggregation is done by Multi Agent Systems and causes to prolong the network lifetime. A Time Division Multiple Access (TDMA) protocol i...
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While wireless sensornetworks are finding an ever increasing number of applications in many areas, they still lack the most powerful human sense - vision. This is largely due to the problems associated with processin...
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While wireless sensornetworks are finding an ever increasing number of applications in many areas, they still lack the most powerful human sense - vision. This is largely due to the problems associated with processing and communicating the large volume of image data over energy constrained sensor nodes. Available wireless sensor nodes are severely constrained in both processing capability and energy. This paper presents an innovative architecture and protocol for energy efficient processing and communication of images over wireless sensornetworks. The proposed hardware architecture is optimized to achieve high speed image compression with minimum hardware requirement and low power consumption. An efficient and reliable transmission protocol for compressed image is also presented. It incorporates an effective image packet queue control strategy to reduce packet error rate and increase image transmission throughput. Experimental results demonstrate the effectiveness of these novel approaches to make image compression and communication over wireless sensornetworks feasible, reliable and efficient.
Flexible minimally invasive surgical instruments can be used to target difficult-to-reach locations within the human body. Accurately steering these instruments requires information about the three-dimensional shape o...
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ISBN:
(纸本)9781467363587
Flexible minimally invasive surgical instruments can be used to target difficult-to-reach locations within the human body. Accurately steering these instruments requires information about the three-dimensional shape of the instrument. In the current study, we use an array of Fiber Bragg Grating (FBG) sensors to reconstruct the shape of a flexible instrument. FBG sensors have several advantages over existing imaging modalities, which makes them well-suited for use in a clinical environment. An experimental testbed is presented in this study, which includes a tendon-driven manipulator. A nitinol FBG-wire is fabricated, on which an array of twelve FBG sensors are integrated, and distributed over four different sets. This wire is positioned in the backbone of the manipulator. Axial strains are measured using the FBG sensors, from which the curvature of the manipulator is calculated. The three-dimensional manipulator shape is reconstructed from the curvature, which is used to steer the manipulator tip. We are able to steer the manipulator along various trajectories (two-dimensional and three-dimensional), and also reject disturbance loads. We observe a minimum mean tracking error of 0.67 mm for the circular trajectory in closed-loop control. This study demonstrates the potential of steering flexible minimally invasive surgical instruments using an array of FBG sensors.
Studies show that globally, about 1 in 50 people are living with paralysis and the amount increasing year by year. Paralysis can leave present these people with no interest in life leading to mental depression. An ass...
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