DARPA Dynamic Optical Tags (DOTS) program has as its goal the development of a low cost, small, robust, persistent, low probability of intercept, 2-way tagging, tracking, and locating device that also supports error f...
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ISBN:
(纸本)0819457817
DARPA Dynamic Optical Tags (DOTS) program has as its goal the development of a low cost, small, robust, persistent, low probability of intercept, 2-way tagging, tracking, and locating device that also supports error free data rates in excess of 100 kbps and can be interrogated at ranges up to and beyond 1Km. The program has selected several promising candidates for this device and is in the process of evaluating individually their performance against predetermined milestones to ascertain whether the technology is feasible and the program should continue for further development. In all cases the candidate devices operate as retro-reflecting optical modulators. Upon interrogation by a laser at the correct wavelength and with the correct code, the tags will proceed to modulate the return retro-reflection. While data for the candidate devices are not yet in hand, nevertheless this paper will provide an overview of the nature of the devices under investigation and speculate on how these devices could be employed for unattended ground sensorapplications.
In this paper we examine some of the concerns in the design of systems composed of very large numbers of 'intelligent sensors'. Such systems are now being proposed as a solution for a number of advanced applic...
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ISBN:
(纸本)4907764227
In this paper we examine some of the concerns in the design of systems composed of very large numbers of 'intelligent sensors'. Such systems are now being proposed as a solution for a number of advancedapplications for which they have some real advantages over conventional systems. Some of these proposals, and some systems which have already been built are surveyed. The problems of configuring and maintaining such networks are examined, along with the system design issues raised. The cogent sensor, a sensor endowed with the ability to transform data to information, is put forward as an essential part of realisation of the type of applications envisaged. The design of generic, cogent sensors is also problematic, because the nature of the data-information transform depends on the application. A systems architecture which overcomes this problem is outlined.
In the last decade, rapidly declining sensor costs triggered intense research in sensor technologies and vice versa. This fact led to the deployment of a number of sensor networks. However, these sensor networks tend ...
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ISBN:
(纸本)9780769539515
In the last decade, rapidly declining sensor costs triggered intense research in sensor technologies and vice versa. This fact led to the deployment of a number of sensor networks. However, these sensor networks tend to be deployed in monolithic stovepipe-like systems, limiting interoperability and reusability of both data and workflow components. This paper presents the Live Geography approach, which stands for the integration of real-time measurement data in a fully standardised infrastructure. A particular focus of this paper is dedicated to interoperable geo-sensor webs featuring a high degree of flexibility and portability can be deployed in various monitoring use cases in a variety of application domains.
McQ has developed an advancedsensor system tailored for border monitoring that has been delivered as part of the SBInet program for the Department of Homeland Security (DHS). Technology developments that enhance a br...
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ISBN:
(纸本)9780819471345
McQ has developed an advancedsensor system tailored for border monitoring that has been delivered as part of the SBInet program for the Department of Homeland Security (DHS). Technology developments that enhance a broad range of features are presented in this paper, which address the overall goal of the system to improving unattended ground sensor system capabilities for border monitoring applications. Specifically, this paper addresses a system definition, communications architecture, advanced signal processing to classify targets, and distributed sensor fusion processing.
The reflected intensity change of the Bloch-surface-wave (BSW) resonance influenced by the loss of a truncated one-dimensional photonic crystal structure is numerically analyzed and studied in order to enhance the sen...
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ISBN:
(数字)9781510604704
ISBN:
(纸本)9781510604698;9781510604704
The reflected intensity change of the Bloch-surface-wave (BSW) resonance influenced by the loss of a truncated one-dimensional photonic crystal structure is numerically analyzed and studied in order to enhance the sensitivity of the Bloch-surface-wave-based sensors. The finite truncated one-dimensional photonic crystal structure is designed to be able to excite BSW mode for water (n= 1.33) as the external medium and for p-polarized plane wave incident light. The intensity interrogation scheme which can be operated on a typical Kretschmann prism-coupling configuration by measuring the reflected intensity change of the resonance dip is investigated to optimize the sensitivity. A figure of merit (FOM) is introduced to measure the performance of the one-dimensional photonic crystal multilayer structure under the scheme. The detection sensitivities are calculated under different device parameters with a refractive index change corresponding to different solutions of glycerol in de-ionized (DI)-water. The results show that the intensity sensitivity curve varies similarly with the FOM curve and the sensitivity of the Bloch-surface-wave sensor is greatly affected by the device loss, where an optimized loss value can be got. For the low-loss BSW devices, the intensity interrogation sensing sensitivity may drop sharply from the optimal value. On the other hand, the performance of the detection scheme is less affected by the higher device loss. This observation is in accordance with BSW experimental sensing demonstrations as well. The results obtained could be useful for improving the performance of the Bloch-surface-wave sensors for the investigated sensing scheme.
Recent developments in wireless sensing technology lead to implement advanced algorithms for distributed data processing in various applications;intelligent transportation system is one of the main applications of the...
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ISBN:
(纸本)9780769533308
Recent developments in wireless sensing technology lead to implement advanced algorithms for distributed data processing in various applications;intelligent transportation system is one of the main applications of the advanced networked sensing technology to monitor the environmental conditions for controlling the quality of the products. To ensure the desired performance of a wireless sensor network, the reliability of the network records needs to be evaluated using an efficient data processing algorithm. In this paper, a new application of a bio-inspired technique is introduced for autonomous plausibility checking in a wireless sensor network;at first, an optimized Neuro-immune system is introduced and developed to predict the sensor records;then, performance of the proposed Neuro-immune system is compared with a neural network approximation mechanism. A secondary algorithm evaluates the sensor records to check the plausibility of the records in the wireless sensor network. The proposed data processing algorithm could serve in various applications of wireless sensor networks.
A rigorous full-vectorial modal solution approach based on the finite element method is used to find the propagation properties of THz waveguides. Design approaches are presented to reduce the modal loss. Design of se...
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ISBN:
(纸本)9780819495075
A rigorous full-vectorial modal solution approach based on the finite element method is used to find the propagation properties of THz waveguides. Design approaches are presented to reduce the modal loss. Design of several THz devices, including quantum cascade lasers, plasmonic waveguides, power splitters and narrow-band filters are also presented.
This article presents a new hybrid electro-optic/inductive current sensor for metering and protective relaying applications. The-sensor combines a Rogowski coil with a passive integrator located in the high-voltage en...
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This article presents a new hybrid electro-optic/inductive current sensor for metering and protective relaying applications. The-sensor combines a Rogowski coil with a passive integrator located in the high-voltage environment. An integrated-optic Pockels cell (IOPC) having integrated electrodes provides optical isolation. Test results from 30 A to 30 kA show the sensor to be highly linear, exceeding 0.2% linearity standards. Temperature cycling tests show the ratio error to have a maximum value, of 0.3% over the -30 to +70 degreesC range.
Digital still cameras overtook film cameras in Japanese market in 2000 in terms of sales volume owing to their versatile functions. However, the image-capturing capabilities such as sensitivity and latitude of color f...
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ISBN:
(纸本)0819461083
Digital still cameras overtook film cameras in Japanese market in 2000 in terms of sales volume owing to their versatile functions. However, the image-capturing capabilities such as sensitivity and latitude of color films are still superior to those of digital image sensors. In this paper, we attribute the cause for the high performance of color films to their multi-layered structure, and propose the solid-state image sensors with stacked organic photoconductive layers having narrow absorption bands on CMOS read-out circuits.
A novel fiber sensor for simultaneous measurement of ammonia gas concentration and temperature is proposed. The sensor is fabricated from two sections of single-mode fiber which are cleaved and then a fusion splicer a...
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ISBN:
(数字)9781510604704
ISBN:
(纸本)9781510604698;9781510604704
A novel fiber sensor for simultaneous measurement of ammonia gas concentration and temperature is proposed. The sensor is fabricated from two sections of single-mode fiber which are cleaved and then a fusion splicer and which is then used to fabricate spherically shaped structures at the end facets. The fusion arc is used to soften the glass which naturally assumes a spherical shape due to surface tension. A short section of multimode fiber is then fusion spliced with the two spherical-shaped ends of the single mode fibers so both the core modes and the cladding modes of the multimode fiber are excited to create two kinds of interference dips: One is created by core modes only which is not sensitive to ammonia gas since the core is isolated by the cladding so the effective refractive index of the core does not change when the refractive index of the environment changes, The other dip is created by the coupling of the core mode and cladding mod, which with a suitable coating is sensitive to ammonia gas. Silica sol-gel was prepared and coated on the fiber surface as a sensing layer for detecting ammonia gas concentration. The experimental results show that the two dips have linear wavelength shift responses but with different sensitivities to ammonia gas concentration (5.03x10(-4)nm/ppm for dip1 and -2.5x10(-5)nm/ppm for dip2) and temperature (0.0067 nm/degrees C for dip1 and 0.0149 nm/degrees C for dip2. By constructing a wavelength shifts matrix for the two dips vs. ammonia gas concentration and temperature, both the ammonia gas concentration and temperature can be measured simultaneously.
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