关键词：光机电；传感器；扫描；激活

查看摘要 索取原文[49页]

One-dimensional fiber-bundle arrays may prove useful in a number of radiation sensing applications where radiation detection over large areas is needed. Tests have been performed to evaluate the light generation and transmission characteristics of 15-meter long, 10-fiber bundles of BCF-10, BCF-12, and BCF-20 scintillating fibers (Saint Gobain) exposed to collimated gamma-ray sources. The test set-up used one R9800 (Hamamatsu) photomultiplier tube (PMT) at each end, with a high-speed waveform digitizer to collect data. Time constraints were imposed on the waveform data to perform time-of-flight analysis of the events in the fiber bundles, eliminating spurious noise pulses in the high gain PMTs and also allowing 1-dimensional localization of interactions along the lengths of the fiber bundles. This paper will present the results of these measurements including the attenuation coefficients of the three fiber types and the timing resolution (position uncertainty) possible for each fiber bundle when using the R9800 PMTs.

关键词：光机电；传感器；光纤阵列；单维

查看摘要 索取原文[7页]

The paper considers the problem of distributed estimation of an unknown deterministic scalar parameter (the target signal) in wireless sensor networks (WSNs), in which each sensor receives a single snapshot of the field. The observation or sensing mode is only partially known at the corresponding nodes, perhaps, due to their limited sensing capabilities or other unpredictable physical factors. Specifically, it is assumed that the observation process at a node switches stochastically between two modes, with mode one corresponding to the desired signal plus noise observation mode (a valid observation), and mode two corresponding to pure noise with no signal information (an invalid observation). With no prior information on the local sensing modes (valid or invalid), the paper introduces a learning-based distributed estimation procedure, the mixed detection-estimation (MDE) algorithm, based on closed-loop interactions between the iterative distributed mode learning and estimation. The online learning (or sensing mode detection) step re-assesses the validity of the local observations at each iteration, thus refining the ongoing estimation update process. The convergence of the MDE algorithm is established analytically. Simulation studies show that, in the high signal-to-noise ratio (SNR) regime, the MDE estimation error converges to that of an ideal (centralized) estimator with perfect information about the node sensing modes. This is in contrast with the estimation performance of a naive average consensus based distributed estimator (with no mode learning), whose estimation error blows up with an increasing SNR.

关键词：光机电；传感器；分布式；信息模型

查看摘要 索取原文[6页]

This report describes basic research to analyze and investigate methods for automatic detection and mitigation of sensor and perception data. Specifically, the PI will investigate (1) Metrics for sensor performance in context using multi-modal redundancy and information theoretic approaches; (2) Detection, localization and mitigation of faults and failures using hierarchical causal reasoning for diagnosis; (3) Develop methods for using low- level (e.g., sensor data fusion filter) versus high-level (autonomous inference) processes for automated selection of data to use for perception.

关键词：光机电；传感器；感知故障；数据完整性

查看摘要 索取原文[63页]

This project supports the capability to perform accurate infrasound sensor calibrations using a piston source and large volume chamber whose output has been independently determined and for which the error budget has been accurately assessed. Since the mid 1980s, Los Alamos National Laboratory (LANL) has operated an infrasound sensor calibration chamber that operates over a frequency range of 0.02 to 4 Hz. This chamber has provided sensitivities, volts/Pa, for sensors used by Los Alamos and others. Under the current program we will restore the chamber function, interrupted by an unexpected move, collaborate with researchers at the Sandia National Laboratory (SNL) Facility for Acceptance, Calibration, and Testing (FACT) Site on sensor issues, calibrate sensors as needed and research new methods for sensor response determination.

关键词：光机电；传感器；校准；响应

查看摘要 索取原文[9页]

The novelly designed optical sensor for autonomous ocean monitoring works on equilibrium principles. When the pH-sensitive reagent solution sitting behind a gas-permeable membrane is exposed to seawater, the CO2 molecules present in the seawater diffuse across the membrane into the reagent and induce a pH change. After equilibrium is reached, the fluorescence is measured and the pCO2 data are recovered from a calibration curve. A specific feature of our measurement technique is the use of excitation ratiometric approach. A violet LED (Light Emitting Diode) and a blue LED are used to excite the sensing reagent through an excitation filter and the pCO2 dependent emission is measured through an emission filter by a photodiode.

关键词：光机电；传感器；光学二氧化碳；海洋监测

查看摘要 索取原文[7页]

The purpose of this chapter was to establish an important extension of the techniques provided in the preceding two chapters toward fully decentralized numerical schemes for the sensor scheduling task. Making an explicit use of the so-called randomized gossip algorithms, it was possible to develop efficient approaches for networks with scanning and mobile nodes, which distribute the computational burden across the network. In the context of parameter estimation for DPSs, such an idea has not been exploited yet.

关键词：光机电；传感器；调度；随机八卦算法

查看摘要 索取原文[19页]

In this chapter, some results related to the interpretation and use of data in DPS diagnostics using sensor networks with mobile nodes were presented. Specifically, theoretical research was carried out and computationally efficient methods to determine optimal configurations of mobile sensor networks for contaminating source detection and estimation were developed. What is more, proper implementation and testing of the computer code for verification of the proposed approach were done based on simulations. The key assumption made here was that the paths of the moving sources were unknown, but they were sufficiently smooth to be approximated by combinations of given basis functions. Parametrization of the source trajectories made it possible to reduce the source detection and estimation problem to that of parameter identification. In order to estimate the source and medium parameters, the maximum-likelihood estimation was used.

关键词：光机电；传感器；故障诊断；离散

查看摘要 索取原文[24页]

The objective of this project, was therfore, to develop a prototype sensor technology, membrane-extraction(ME)-IMS, that could be used in situ or ex situ, to characterize the extent of groundwater plumes, conduct compliance monitoring around waste facilities or at the leading edge of a plume, and monitor re,merial actions. The IMS instrument could also be used to monitor CHC in the vapor phase.

关键词：光机电；传感器；地下水；原位监测

查看摘要 索取原文[45页]

The objective of the work reported herein was to use a systems engineering approach to guide development of integrated instrumentation/sensor systems (IISS) incorporating communications, interconnections, and signal acquisition. These require enhanced suitability and effectiveness for diagnostics and health management of aerospace equipment governed by the principles of Condition-based maintenance (CBM). It is concluded that the systems engineering approach to IISS definition provided clear benefits in identifying overall system requirements and an architectural framework for categorizing and evaluating alternative architectures, relative to a bottom up focus on sensor technology blind to system level user needs. CBM IISS imperatives identified include factors such as tolerance of the bulk of aerospace equipment operational environments, low intrusiveness, rapid reconfiguration, and affordable life cycle costs. The functional features identified include interrogation of the variety of sensor types and interfaces common in aerospace equipment applications overmultiplexed communication media with flexibility to allow rapid system reconfiguration to adapt to evolving sensor needs. This implies standardized interfaces at the sensor location (preferably to open standards), reduced wire/connector pin count in harnesses (or their elimination through use of wireless communications).

关键词：光机电；传感器；航空航天设备；仪表维修

查看摘要 索取原文[8页]