A novel optical waveguide microcantilever sensor for the detection of nanomechanical forces

This study presents a novel generic multipurpose probe based on an array of 20 waveguide channels with microcantilevers acting as optical waveguides operated in the visible range. The principle of operation is based on the sensitivity of energy transfer between two butt-coupled waveguides to their misalignment with respect to each other. The technique can be considered an alternative to the known methods used for the readout of the nanomechanical response of microcantilevers to the external force exerted on them. The cantilever displacement can be detected with a resolution of 18 fm//spl radic/Hz. The limit is generally defined by the shot noise of a conventional photodetector used for the readout of the output signal. Real-time parallel monitoring of several channels can be realized. In contrast to devices based on the atomic force microscope detection principle, no preliminary alignment or adjustment, except for light coupling, is required. The detection of the cantilever deflection at subnanometer range was demonstrated experimentally.     

A CMOS, fully integrated sensor for electronic detection of DNA hybridization

An integrated field-effect device for fully electronic deoxyribonucleic acid (DNA) detection was realized in a standard CMOS process. The device is composed of a floating-gate MOS transistor, a control-capacitor acting as integrated counterelectrode, and an exposed active area for DNA immobilization. The drain-current of the transistor is modulated by the electric charge carried by the DNA molecules. After DNA hybridization, this charge increases and a change in the output current is measured. Experimental results are provided. Full compatibility with a standard CMOS process opens the way to the realization of low-cost large-scale integration of fast electronic DNA detectors.     

A novel intrinsic multimode fiber-optic sensor for the detection or monitoring of microwave power

A graded-index silica multimode fiber with an acrylate primary coating has been shown to act as an intrinsic sensor of microwave power. When under the influence of a microwave field, the fiber absorbs a small fraction of microwave energy and this alters the propagation condition for transmitted laser light (632.8 nm). This alteration is manifested in the speckle pattern which is projected, after transmission, from the cut end of the fiber, and is recorded either by an optical detector or by visual observation. The rate of change of the speckle pattern is the important feature. The sensitivity of the effect increases as the microwave power increases, as the fiber length increases, and when the fiber is coated with conducting silver paint. Microwave powers, transmitted at 2.45 GHz in a rectangular waveguide is in the range 0.07-700 W were detected with an accuracy of better than 2 dB. These power levels correspond to electric field levels of2.8 times 10^{2}V . m^-1and2.8 times 10^{4}V . m^-1at the position of the fiber. The results are briefly compared with recent similar observations using a silica single-mode fiber as the sensor and an interferometer as detector. Discussions relate to use of the speckle pattern for detection and to possible applications.     

A novel sine‐curve mobility model for intrusion detection in wireless sensor networks

Intrusion detection is prominently important for civil and military applications in wireless sensor networks (WSNs). To date, related works address the problem by assuming a straight‐line intrusion path and a Boolean sensing model. However, a straight‐line intrusion path is often not the case in reality, and the Boolean sensing model cannot resemble a real‐world sensor precisely. Results based on these assumptions are therefore not applicable with desirable accuracy in practice. In view of this, we propose a novel sine‐curve mobility model that can simulate different intrusion paths by adjusting its features (amplitude, frequency, and phase) and can be integrated into the random WSN model for intrusion detection analysis. It can also be applied to different sensor models and makes influencing factors tractable. With the model, we examine the effects of different intrusion paths on the intrusion detection probability in a random WSN, considering both Boolean and realistic Elfes sensing models. Further, we investigate the interplays between network settings and intruder's mobility patterns and identify the benefits and side effects of the model theoretically and experimentally. Simulation outcomes are shown to match well with the theoretical results, validating the modeling, analysis, and conclusions. Copyright © 2011 John Wiley & Sons, Ltd.     

A novel fault detection and recovery technique for cluster‐based underwater wireless sensor networks

The performance of underwater wireless sensor network gets affected by the working of a cluster in the network. The cluster head (CH) or cluster member (CM) fails because of energy depletion or hardware errors that increase delay and message overhead of the network. To recover the affected cluster, a technique is required to identify the failed CH or CM. We propose a fault detection and recovery technique (FDRT) for a cluster‐based network in this paper. Primarily, while selecting the CH, a backup cluster head (BCH) is selected using fuzzy logic technique based on parameters such as node density, residual energy, load, distance to sink, and link quality. Then, failure of CH, BCH, and CM is detected. If fault is detected at CH, then the BCH will start performing the task of failed CH. Simultaneously, when BCH failed, any other CM will be elected as BCH. If any of the CM appears to be nonperforming, then CH will detect the communication failure and request BCH to transfer the data from the failed CM to CH. The comparison of proposed FDRT is performed with existing FDRTs EDETA, RCH, and SDMCGC on the basis of packet drop, end‐to‐end delay, energy consumption, and delivery ratio of data packets. By simulation results, it is shown that FDRT for cluster‐based underwater wireless sensor network results in quicker detection of failures and recovery of the network along with the reduction in energy consumption, thereby increasing the lifespan of the network.     

A novel airflow sensor for miniature mobile robots

A novel airflow sensor has been developed for applications involving miniature chemical sensing robots. Information about air movement is essential for robots when they are searching for the sources of chemical plumes. The airflow sensor described here measures both wind direction and velocity at airflow rates commonly encountered in an indoor environment. Measurements are made by rotating a small paddle in the airflow. The varying speed of the paddle is analysed to determine both wind speed and direction. Low power consumption and rugged construction make the sensor well suited to robotic applications. The prototype sensor is small enough to fit on a mobile robot measuring only 10 cm in diameter. This paper presents the sensor operating principle, construction and some experimental results.     

Design and characterization of novel read-out systems for a capacitive DNA sensor

This paper presents novel read-out electronic systems for a fast DNA label-less detection. The capacitive shift due to the hybridization effect is monitored by means of a charge sensitive amplifier and a differential stage. The systems provide an A/D conversion and an evaluation of the capacitive shift amount with a resolution of 11 bit. The read-out solutions demonstrate the ability to identify a 0.01% variation on the capacitive value of the sensor. The investigated techniques are suitable for monolithic systems or for a micro-fabricated array of sensors.     

压力传感器温度补偿的一种新方法

针对温度对硅压阻式压力传感器输出影响的问题,提出将主成分分析(PCA)与改进的反向传播(BP)神经网络相结合,用于压力传感器的温度补偿的新方法.利用PCA提取温度补偿的主要信息使多维问题得以简化,同时剔除了数据的噪声误差,且对BP神经网络进行了改进,以充分发挥其强大的泛化功能和容错能力.研究结果表明,该方法有效抑制了温...     

A novel semiconductor capacitive sensor for a single-chipfingerprint sensor/identifier LSI

We describe a new semiconductor capacitive sensor structure and the fabrication process for a single-chip fingerprint sensor/identifier LSI in which the sensor is stacked on a 0.5-μm CMOS LSI. To ascertain the influence of the fabrication process and normal usage on the underlying LSI, sensor chips were subjected to an electrostatic discharge (ESD) test, mechanical stress test, and unsaturated pressure cooker test (USPCT). ESD tolerance is obtained at the value of ±3.0 kV. To investigate mechanical stress, we carried out a tapping test. The sensor is immune to mechanical stress under the condition of 10⁴ taps with the strength of 1 MPa. A multilayer passivation film consisting SiN under polyimide film provides protection against contamination such as water. Thus, under USPCT conditions of 130°C, 80% humidity, and 48 h, the chips were not degraded. The tests confirm that the proposed sensor has sufficient reliability for normal identification usage     

A CMOS active pixel sensor based DNA micro-array with nano-metallic particles detection protocol

A DNA micro-array (DMA) for DNA detection is reported. The DMA combines a standard CMOS active pixel image sensor with a DNA detection protocol utilizing the binding of DNA targets and probes functionalized with gold nano-particles that can modify the opaqueness at the detection site. The DMA has been fabricated using a 0.5 μm CMOS process together with on-chip timing control and correlated double sampling. Experimental results show that the system can detect DNA samples with extremely low concentration down to 10 pM using ordinary light source.     

Wavefront detection performance analysis of plenoptic sensor

A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intensities. The results show that the plenoptic sensor can achieve better distortion wavefront detection, and its wavefront detection accuracy improves with turbulence intensity. The unique optical structure design of the plenoptic sensor makes it more suitable for aberration wavefront d...     

A novel wavelet transform-based transient current analysis for fault detection and localization

Transient current (IDD) testing has been often cited and investigated as an alternative and/or supplement to quiescent current (IDDQ) testing. In this correspondence, we present a novel integrated method for fault detection and localization using wavelet transform-based IDD waveform analysis. The time-frequency resolution property of wavelet transform helps us detect as well as localize faults in digital CMOS circuits. Experiments performed on measured data from a fabricated 8-bit shift register, and simulation data from more complex circuits show promising results for both detection and localization. Wavelet-based detection method shows better sensitivity than spectral and time-domain methods. Effectiveness of the localization method in presence of complex power supply network, measurement noise, and process variation is also addressed.     

一种SOI高温压力传感器

SOI高温压力传感器是一种新型的高性能,高品质的压力传感器。本文提出了一种SOI高温压力传感器的结构,并从掺杂浓度和功率等关键因素进行了高温分析。设计了敏感芯片 的工艺流程以及关键工艺参数。通过在室温和高温下的测量,结果表明非线性误差小于0.1%,迟滞性小于0.5%,敏感芯片可以在350℃高温下工作。本文为高温压力传感器的研究提供了参考。     

A novel structure for the intrinsic Fabry-Perot fiber-optictemperature sensor

A novel structure of the intrinsic Fabry-Perot interference (IFPI) fiber temperature sensor is presented. The sensor uses two different core diameter fibers and produces a reflective mirror by fusing uncoated bare fibers. This procedure not only solves the problem of controlling thickness and reflectance of the thin film but also provides easier and cheaper technologies for IFPI fiber sensors. Theoretical and experimental aspects of the intrinsic Fabry-Perot cavity are described. Both theoretical and experimental results from this novel structure show good agreement with those from the traditional Fabry-Perot fiber sensor     

A lightweight intrusion detection framework for wireless sensor networks

In recent years, Wireless Sensor Networks (WSNs) have demonstrated successful applications for both civil and military tasks. However, sensor networks are susceptible to multiple types of attacks because they are randomly deployed in open and unprotected environments. It is necessary to utilize effective mechanisms to protect sensor networks against multiple types of attacks on routing protocols. In this paper, we propose a lightweight intrusion detection framework integrated for clustered sensor networks. Furthermore, we provide algorithms to minimize the triggered intrusion modules in clustered WSNs by using an over‐hearing mechanism to reduce the sending alert packets. Our scheme can prevent most routing attacks on sensor networks. In in‐depth simulation, the proposed scheme shows less energy consumption in intrusion detection than other schemes. Copyright © 2009 John Wiley & Sons, Ltd.     

Efficient deployment quality analysis for intrusion detection in wireless sensor networks

The intrusion detection in a Wireless Sensor Network is defined as a mechanism to monitor and detect any intruder in a sensing area. The sensor deployment quality is a critical issue since it reflects the cost and detection capability of a wireless sensor network. The quality of deterministic deployment can be determined sufficiently by a rigorous analysis before the deployment. However, when random deployment is required, determining the deployment quality becomes challenging. In the intrusion detection application, it is necessary to define more precise measures of sensing range, transmission range, and node density that impact overall system performance. The major question is centred around the quality of intrusion detection in WSN, how we can guarantee that each point of the sensing area is covered by at least one sensor node, and what a sufficient condition to guarantee the network connectivity? In this paper, we propose an appropriate probabilistic model which provides the coverage and connectivity in k-sensing detection of a wireless sensor network. We have proved the capability of our approach using a geometric analysis and a probabilistic model.     

A novel ensembled technique for anomaly detection

Anomaly detection is a technique that works to detect those instances of data that do not comply with the data model. In this paper the problem of anomaly detection in networked traffic data is considered, and a novel ensembled technique for anomaly detection is proposed. The proposed technique uses a combination of fuzzy K‐means clustering algorithm, extended Kalman filter, and support vector machines to detect the anomalies. In the proposed technique, fuzzy membership functions are used instead of crisp clusters to compute the best set of features by fuzzy k‐means algorithm. These features are then optimized with a nonlinear Bayesian approach known as extended Kalman filter. The resultant optimized set of features is then provided as an input to the support vector machine classifier that detects the network anomalies. The proposed technique is validated by using 2 benchmark datasets, ie, DARPA 1998 and KDD CUP 1999. Experimental results indicate that the proposed technique performs quite well as compared to its traditional counterparts in accuracy, detection rate, false positive rate, and F‐score.     

Asynchronous failed sensor node detection method for sensor networks

Detecting failed nodes is important in a sensor network, because a failed node can cause coverage and connectivity holes. Since sensors are resource‐limited devices, lack of a clocking mechanism imposes difficulties in implementing synchronous failure detection techniques. To counter this, asynchronous methods are needed for detecting failed sensor nodes. For example, in traditional distributed systems sent data packets and received acknowledgements are matched to identify any malfunctions. A similar approach can be adopted in sensor networks. An asynchronous failed sensor node detection (AFSD) method is proposed, where a numeric counter variable is used to track the received and sent data packets between active nodes. This variable acts as bounded for an active sensor node and unbounded for an out‐of‐communication or failed node. By observing the value of the counter, a decision can be made on a deployed sensor node. Whenever the counter value of a neighbour crosses a predefined threshold, that neighbour is suspected. However, measuring a counter value can always lead to a false positive. To avoid false suspicion, a consensus protocol is needed. Such a technique is described, which is proved as accurate and complete. The complexity analysis shows that the control, energy, and time overheads of the proposed method are linear and in the order of number of neighbours per node. Copyright © 2011 John Wiley & Sons, Ltd.     

A novel mathematical model for coverage in wireless sensor network

1 Introduction With the development of the sensor, wireless communication, and computer science, many researches have been focused on the development of a novel wireless network named wireless Ad-hoc sensor networks. This network can be defined as a network that can be self-organized in Ad-hoc fashion. This includes many sensor nodes and its objective is to sense, collect, and process the information collected by the individual sensor nodes via their cooperation [2]. Because of its high pract…     

The novel communication algorithm and the throughput analysis for wireless sensor networks

Aiming at the significance of the energy controls of wireless sensor networks, an economical energy consumption algorithm for wireless communicating in Wireless Sensor Networks (WSN) is presented. Based on the algorithm, the maximal system throughput of WSN is analyzed, and the upper bound of throughput of WSN is proposed and proved. Some numerical simulations are conducted and analyzed. The conclusions include that the transmitting radius of sensor node and the parameters of the energy cost function have significant influence upon the throughput, but the monitoring region radius has little influence. For the same transmitting distance, the more the hopping of information trans- mitting, the better the throughput of WSN. On the other hand, for the energy optimization of the whole WSN, the trade-off problem between the throughput capacity and the relay nodes is proposed, and the specific expression of relay hops that minimized the energy consumptions and the maximal throughput of WSN under the specific situation is derived.