• 제목/요약/키워드: Sensing Data

검색결과 4,799건 처리시간 0.031초

Quantitative Application of TM Data in Shallow Geological Structure Reconstruction

  • Yang, Liu;Liqun, Zou;Mingxin, Liu
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
    • /
    • pp.1313-1315
    • /
    • 2003
  • This paper is dedicated to studying the quantitative analysis method with remote-sensing data in shallow geological structure reconstruction by the example of TM data in western China. A new method of computing attitude of geological contacts from remote-sensing data is developed and assessed. We generate several geological profiles with remotely derived measurements to constrain the shallow geological structure reconstruction in three dimensions.

  • PDF

Efficient Measurement Method for Spatiotemporal Compressive Data Gathering in Wireless Sensor Networks

  • Xue, Xiao;Xiao, Song;Quan, Lei
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • 제12권4호
    • /
    • pp.1618-1637
    • /
    • 2018
  • By means of compressive sensing (CS) technique, this paper considers the collection of sensor data with spatiotemporal correlations in wireless sensor networks (WSNs). In energy-constrained WSNs, one-dimensional CS methods need a lot of data transmissions since they are less applicable in fully exploiting the spatiotemporal correlations, while the Kronecker CS (KCS) methods suffer performance degradations when the signal dimension increases. In this paper, an appropriate sensing matrix as well as an efficient sensing method is proposed to further reduce the data transmissions without the loss of the recovery performance. Different matrices for the temporal signal of each sensor node are separately designed. The corresponding energy-efficient data gathering method is presented, which only transmitting a subset of sensor readings to recover data of the entire WSN. Theoretical analysis indicates that the sensing structure could have the relatively small mutual coherence according to the selection of matrix. Compared with the existing spatiotemporal CS (CS-ST) method, the simulation results show that the proposed efficient measurement method could reduce data transmissions by about 25% with the similar recovery performance. In addition, compared with the conventional KCS method, for 95% successful recovery, the proposed sensing structure could improve the recovery performance by about 20%.

Derivation of SST using MODIS direct broadcast data

  • Chung, Chu-Yong;Ahn, Myoung-Hwan;Koo, Ja-Min;Sohn, Eun-Ha;Chung, Hyo-Sang
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
    • /
    • pp.638-643
    • /
    • 2002
  • MODIS (MODerate-resolution Imaging Spectroradiometer) onboard the first Earth Observing System (EOS) satellite, Terra, was launched successfully at the end of 1999. The direct broadcast MODIS data has been received and utilized in Korea Meteorological Administration (KMA) since february 2001. This study introduces utilizations of this data, especially for the derivation of sea surface temperature (SST). To produce the MODIS SST operationally, we used a simple cloud mask algorithm and MCSST algorithm. By using a simple cloud mask algorithm and by assumption of NOAA daily SST as a true SST, a new set of MCSST coefficients was derived. And we tried to analyze the current NASA's PFSST and new MCSST algorithms by using the collocated buoy observation data. Although the number of collocated data was limited, both algorithms are highly correlated with the buoy SST, but somewhat bigger bias and RMS difference than we expected. And PFSST uniformly underestimated the SST. Through more analyzing the archived and future-received data, we plan to derive better MCSST coefficients and apply to MODIS data of Aqua that is the second EOS satellite. To use the MODIS standard cloud mask algorithm to get better SST coefficients is going to be prepared.

  • PDF

Mitigation of Adverse Effects of Malicious Users on Cooperative Spectrum Sensing by Using Hausdorff Distance in Cognitive Radio Networks

  • Khan, Muhammad Sajjad;Koo, Insoo
    • Journal of information and communication convergence engineering
    • /
    • 제13권2호
    • /
    • pp.74-80
    • /
    • 2015
  • In cognitive radios, spectrum sensing plays an important role in accurately detecting the presence or absence of a licensed user. However, the intervention of malicious users (MUs) degrades the performance of spectrum sensing. Such users manipulate the local results and send falsified data to the data fusion center; this process is called spectrum sensing data falsification (SSDF). Thus, MUs degrade the spectrum sensing performance and increase uncertainty issues. In this paper, we propose a method based on the Hausdorff distance and a similarity measure matrix to measure the difference between the normal user evidence and the malicious user evidence. In addition, we use the Dempster-Shafer theory to combine the sets of evidence from each normal user evidence. We compare the proposed method with the k-means and Jaccard distance methods for malicious user detection. Simulation results show that the proposed method is effective against an SSDF attack.

A Southeast Asia Environmental Information Web Portal

  • Low, John;Liew, Soo-Chin;Lim, Agnes;Chang, Chew-Wai;Kwoh, Leong-Keong
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
    • /
    • pp.1006-1008
    • /
    • 2003
  • In this paper, we describe the development of a Southeast Asia environmental information web portal based on near real time MODIS Level 2 and higher level products generated from the direct broadcast data received at the Centre for Remote Imaging, Sensing and Processing (CRISP). This web portal aims to deliver timely environmental information to interested users in the region. Interpreted data will be provided instead of raw satellite data to reduce operational requirements on our system, and to enable users with limited bandwidths to have access to the system.

  • PDF

ARX모델기반 가상센싱을 통한 사장교 케이블의 장력 추정 (Estimation of Cable Tension Force by ARX Model-Based Virtual Sensing)

  • 최가희;신수봉
    • 한국지진공학회논문집
    • /
    • 제21권6호
    • /
    • pp.287-293
    • /
    • 2017
  • Sometimes, it is impossible to install a sensor on a certain location of a structure due to the size of a structure or poor surrounding environments. Even if possible, sensors can be frequently malfunctioned or improperly operated due to lack of adequate maintenance. These kind of problems are solved by the virtual sensing methods in various engineering fields. Virtual sensing technology is a technology that can measure data even though there is no physical sensor. It is expected that this technology can be also applied to the construction field effectively. In this study, a virtual sensing technology based on ARX model is proposed. An ARX model is defined by using the simulated data through a structural analysis rather than by actually measured data. The ARX-based virtual sensing model can be applied to estimate unmeasured response using a transfer function that defines the relationship between two point data. In this study, a simulation and experimental study were carried out to examine the proposed virtual sensing method with a laboratory test on a cable-stayed model bridge. Acceleration measured at a girder is transformed to estimate a cable tension through the ARX model-based virtual sensing.

리모트센싱과 GIS의 통합 및 그 적용기법에 관한 연구 (A Study on the Application Technique and Integration of Remote Sensing and Geographic Information System)

  • 안철호;연상호
    • 한국측량학회지
    • /
    • 제9권1호
    • /
    • pp.97-107
    • /
    • 1991
  • 본 연구에서는 리모트센싱과 GIS의 장점을 살려 하나의 시스템에서 여러 기능을 복합적으로 이용하기 위한 리모트센싱과 GIS의 통합을 시도한 것이다. 래스터와 벡터 데이타의 동시 통합 출력을 위한 중복 알고리즘을 개발하였으며, 리모트센싱과 GIS의 통합결과를 시험적용하기 위하여 인공위성 화상 데이타와 지형도 벡터 그래픽 데이타를 정확하게 통합시켰다. 실제 적용에서는 리모트센싱과 GIS의 주요 적용분야의 주제별 적용에 대한 데이타 모집과 중복 그리고 좌표계 변환을 통하여 대상지역에 다각적으로 적용할 수 있는 기법을 시도함으로써 벡터와 래스터의 중복의 효용성을 입증하고 복합적인 현안분석을 통해서 리모트센싱과 GIS의 복합적용을 위한 새로운 적용 기법을 제시하였다.

  • PDF

Developing the Cloud Detection Algorithm for COMS Meteorolgical Data Processing System

  • Chung, Chu-Yong;Lee, Hee-Kyo;Ahn, Hyun-Jung;Ahn, Myoung-Hwan;Oh, Sung-Nam
    • 대한원격탐사학회지
    • /
    • 제22권5호
    • /
    • pp.367-372
    • /
    • 2006
  • Cloud detection algorithm is being developed as primary one of the 16 baseline products of CMDPS (COMS Meteorological Data Processing System), which is under development for the real-time application of data will be observed from COMS Meteorological Imager. For cloud detection from satellite data, we studied two different algorithms. One is threshold technique based algorithm, which is traditionally used, and another is artificial neural network model. MPEF scene analysis algorithm is the basic idea of threshold cloud detection algorithm, and some modifications are conducted for COMS. For the neural network, we selected MLP with back-propagation algorithm. Prototype software of each algorithm was completed and evaluated by using the MTSAT-IR and GOES-9 data. Currently the software codes are standardized using Fortran90 language. For the preparation as an operational algorithm, we will setup the validation strategy and tune up the algorithm continuously. This paper shows the outline of the two cloud detection algorithms and preliminary test results of both algorithms.