• 제목/요약/키워드: distributed sensing

검색결과 412건 처리시간 0.027초

DISTRIBUTED WEB GIS SERVICE BASED ON XML AND INTEROPERABILITY

  • Kim, Do-Hyun
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.145-150
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    • 2002
  • Web GIS (Geographic Information Systems) service systems provide the various GIS services of analyzing and displaying the spatial data with friendly user-interface. These services are expanding the business domain and many users want to access the distributed various spatial data. But, it is difficult to access diverse data sources because of different spatial data format and data access methods. In this paper, we design and implement web GIS services based on the inter-operability and GML (Geography Markup Language) of OGC(Open GIS Consortium) in web distributed environment. Inter-operability provides unique accessing method to distributed data sources based on OLE DB technology of Microsoft. In addition, GML support web GIS services based on XML. We design these GIS services as components using UML (Unified Modeling Language) of an object-oriented modeling language for specifying, visualizing, constructing, and documenting the artifacts of software system. In addition, they also were developed in object-oriented computing environment, and it provides the interoperability, language-independent, easy developing environment as well as re-usability.

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Design and evaluation of a distributed TDR moisture sensor

  • Zhang, Bin;Yu, Xinbao;Yu, Xiong
    • Smart Structures and Systems
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    • 제6권9호
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    • pp.1007-1023
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    • 2010
  • This paper describes the development and evaluation of an innovative TDR distributed moisture sensor. This sensor features advantages of being responsive to the spatial variations of the soil moisture content. The geometry design of the sensor makes it rugged for field installation. Good linear calibration is obtained between the sensor measured dielectric constant and soil physical properties. Simulations by the finite element method (FEM) are conducted to assist the design of this sensor and to determine the effective sampling range. Compared with conventional types of moisture sensor, which only makes point measurement, this sensor possesses distributed moisture sensing capability. This new sensor is not only easy to install, but also measures moisture distribution with much lower cost. This new sensor holds promise to significantly improve the current field instruments. It will be a useful tool to help study the influence of a variety of moisture-related phenomena on infrastructure performance.

Energy Detection Based Sensing for Secure Cognitive Spectrum Sharing in the Presence of Primary User Emulation Attack

  • Salem, Fatty M.;Ibrahim, Maged H.;Ibrahim, I.I.
    • IEIE Transactions on Smart Processing and Computing
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    • 제2권6호
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    • pp.357-366
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    • 2013
  • Spectrum sensing, as a fundamental functionality of Cognitive Radio (CR), enables Secondary Users (SUs) to monitor the spectrum and detect spectrum holes that could be used. Recently, the security issues of Cognitive Radio Networks (CRNs) have attracted increasing research attention. As one of the attacks against CRNs, a Primary User Emulation (PUE) attack compromises the spectrum sensing of CR, where an attacker monopolizes the spectrum holes by impersonating the Primary User (PU) to prevent SUs from accessing the idle frequency bands. Energy detection is often used to sense the spectrum in CRNs, but the presence of PUE attack has not been considered. This study examined the effect of PUE attack on the performance of energy detection-based spectrum sensing technique. In the proposed protocol, the stationary helper nodes (HNs) are deployed in multiple stages and distributed over the coverage area of the PUs to deliver spectrum status information to the next stage of HNs and to SUs. On the other hand, the first stage of HNs is also responsible for inferring the existence of the PU based on the energy detection technique. In addition, this system provides the detection threshold under the constraints imposed on the probabilities of a miss detection and false alarm.

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1차 사용자의 랜덤 트래픽하에서 스펙트럼 센싱의 성능을 향상시키기 위한 방법 (A Method to enhance the Performance of Spectrum Sensing Under a Random Traffic of Primary User)

  • 공형윤
    • 한국인터넷방송통신학회논문지
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    • 제13권6호
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    • pp.87-92
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    • 2013
  • 본 논문에서는 로컬 스펙트럼 감지 성능에서 1차 사용자 신호의 영향을 분석하는 데 초점을 맞추었다. 감지시간의 표본에서 신호 도착의 확률은 감지 시간에 따라 일정하게 분산되어있다. PU 신호의 임의의 도착에 따라 기존의 에너지 감지(CED)의 검출 결과에 저하를 일으키는 주요 요인을 분석한다. 따라서, PU 신호의 도착을 검출을 추정하고 복합 에너지 검출과 협동하여 검출 성능을 향상시키기 위한 방법을 제안한다. 수학적 분석과 시뮬레이션은 CED와 비교하여 제안된 기법의 출력이 적합한지 확인한다.

Temperature Compensation of a Strain Sensing Signal from a Fiber Optic Brillouin Optical Time Domain Analysis Sensor

  • Kwon, Il-Bum;Kim, Chi-Yeop;Cho, Seok-Beom;Lee, Jung-Ju
    • Journal of the Optical Society of Korea
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    • 제7권2호
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    • pp.106-112
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    • 2003
  • In order to do continuous health monitoring of large structures, it is necessary that the distributed sensing of strain and temperature of the structures be measured. So, we present the temperature compensation of a signal from a fiber optic BOTDA (Brillouin Optical Time Domain Analysis) sensor. A fiber optic BOTDA sensor has good performance of strain measurement. However, the signal of a fiber optic BOTDA sensor is influenced by strain and temperature. Therefore, we applied an optical fiber on the beam as follows: one part of the fiber, which is sensitive to the strain and the temperature, is bonded on the surface of the beam and another part of the fiber, which is only sensitive to the temperature, is located nearby the strain sensing fiber. Therefore, the strains can be determined from the strain sensing fiber while compensating for the temperature from the temperature sensing fiber. These measured strains were compared with the strains from electrical strain gages. After temperature compensation, it was concluded that the strains from the fiber optic BOTDA sensor had good coincidence with those values of the conventional electrical strain gages.

USING SATELLITE SYNTHETIC APERTURE RADAR IMAGERY TO MAP OIL SPILLS IN THE EAST CHINA SEA

  • Shi, Lijian;Ivanov, Andrei Yu.;He, Mingxia;Zhao, Chaofang
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.981-984
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    • 2006
  • Oil pollution of the ocean is a major environmental problem, especially in its coastal zones. Synthetic aperture radar (SAR) flown on satellites, such as ERS-2 and Envisat, has been proved to be a useful tool in oil spill monitoring due to its wide coverage, day and night, and all-weather capability. The total 120 SAR images containing oil spill over the East China Sea were collected and analyzed, ranging in date from July 23, 2002 to November 11, 2005. After preprocessed, SAR images were segmented by adaptive threshold method. The oil spill images were incorporated into GIS after distinguished from look-like phenomena, finally we presented the oil spills distribution map for the East China Sea. The wide-swath and quick-looks SAR imagery for mapping of oil spill distribution over large marine areas were proved to be useful when full resolution data are not available. After the temporal and spatial distribution of the oil spills were analyzed, we found that most of oil spills were distributed along the main ship routes, which means the illegal discharge by ships, and the occurrence of oil spill detected on SAR images acquired during morning and summer is much higher than during evening and winter.

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Reweighted L1 Minimization for Compressed Sensing

  • 이혁;박선호;심병효
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송공학회 2010년도 하계학술대회
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    • pp.61-63
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    • 2010
  • Recent work in compressed sensing theory shows that m${\times}$n independent and identically distributed sensing matrices whose entries are drawn independently from certain probability distributions guarantee exact recovery of a sparse signal with high probability even if m${\ll}$n. In particular, it is well understood that the L1 minimization algorithm is able to recover sparse signals from incomplete measurements. In this paper, we propose a novel sparse signal reconstruction method that is based on the reweighted L1 minimization via support recovery.

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Parallel Fuzzy Inference Method for Large Volumes of Satellite Images

  • Lee, Sang-Gu
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제1권1호
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    • pp.119-124
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    • 2001
  • In this pattern recognition on the large volumes of remote sensing satellite images, the inference time is much increased. In the case of the remote sensing data [5] having 4 wavebands, the 778 training patterns are learned. Each land cover pattern is classified by using 159, 900 patterns including the trained patterns. For the fuzzy classification, the 778 fuzzy rules are generated. Each fuzzy rule has 4 fuzzy variables in the condition part. Therefore, high performance parallel fuzzy inference system is needed. In this paper, we propose a novel parallel fuzzy inference system on T3E parallel computer. In this, fuzzy rules are distributed and executed simultaneously. The ONE_To_ALL algorithm is used to broadcast the fuzzy input to the all nodes. The results of the MIN/MAX operations are transferred to the output processor by the ALL_TO_ONE algorithm. By parallel processing of the fuzzy rules, the parallel fuzzy inference algorithm extracts match parallelism and achieves a good speed factor. This system can be used in a large expert system that ha many inference variables in the condition and the consequent part.

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리니어 모터를 위한 능동 자기 베어링의 설계 및 제어 (Design and Control of an Active Magnetic Bearing for Linear Motors)

  • 양광원;허경무
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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    • pp.119-122
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    • 2001
  • This paper deals with new type of active magnetic bearing (AMB) for the linear motors. We adopted optical sensing mechanism for the gap sensing. Using the laser and the PSD (Position Sensitive Device), the absolute rotor position is obtained independent of the profile of the guide rail. With this measurement, the rotor can be controller to follow the straight beam of the laser. Another advantage of optical sensing mechanism might be the elimination of the possible interference between the proximity sensor and the electro-magnet. By adopting the push-full actuating mechanism, the bearing stiffness is increased near the equilibrium position. For the simplicity, distributed control system is constructed. Eight independent PID control algorithm is used with the full order observer. Several simulation md test results are presented.

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LANDSAT TM 자료에 의한 영남지역의 광산대조사 및 응용방법 개발(III) (Remote Sensing Application for the Mineralized Zone in Ryeongnam Area Using LANDSAT TM Data (III))

  • 姜必鍾;智光薰
    • 대한원격탐사학회지
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    • 제5권2호
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    • pp.91-107
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    • 1989
  • The purpose of this study is to investigate ways to use Landsat TM data for geological mapping and minieralized area detection. The study was carried out in Kyongju-Pohang area where toseki and bentonite mines are distributed. Rock samples of 18 granites, andesites, toseki, betonites, sedimentary rocks and altered rocks in the study area were collected for the study. The radiometric measurtment of the rock samples were carried out with a radiometer in the laboratory and in the field. The Landsat TM bands 2,3,4,5,7 were used for the measurement. The radiometric characteristics of the sample were mainly processed by the principal component analysis. It was found that the pricipal component analysis of the radiometric characteristics of geologic materials is very useful for the detection of the alteration of rocks and grade of mineral contents. It is expected that the technique can be used in the future for the efficient exploration of minerals in this country and abroad.