• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.580-584
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• 2006

Material information for environment may be useful to accomplish mobile robot localization. A procedure to classify a set of indoor materials (glass, steel, wood, aluminum and concrete) with the reflected signal of ultrasonic sensor is proposed in this paper. The main idea is to use material-specific reflection characteristics for the recognition of material type. To achieve the classification task, we modeled reflected signal as a maximum amplitude with respect to distance. In this way, we can generate echo signal models for the given materials and these models are used to compare with the current sensor reading. The experimental results show that the proposed method may give material information during map building task of mobile robot.

• 농촌지도와개발
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• 제3권2호
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• pp.167-176
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• 1996

Localization process of agricultural extension personnel in Korea were in progress with insufficient debates for effective personnel management. Although the members of the Korean Agricultural Extension Society were strongly opposed to the plan to decentralize agricultural extension personnel from central to local government status, the administrative action took place to localize as of January 1997. The Korean Agricultural Extension Society filed the petition against to the plan pinpointing lowered morale of extension personnel, the financial burden of local governments, jeopardizing stability, undermining efficiency, and people`s attitude towards central and local government. The dangers of decentralization of agricultural extension services may cause serious problems in varied areas. More extensive debates would be needed in deciding the future directions of agricultural extension services analyzing the basic characteristics of agricultural extension, linkages of research and extension, financial burden of local government, specialization of extension personnel, and unnecessary duplication of investment among local governments.

• Structural Engineering and Mechanics
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• 제5권6호
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• pp.785-801
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• 1997

Reinforced Concrete beams with tension and compression softening material constitutive laws are studied. Energy-based and non-local regularisation techniques are presented and applied to a R.C. element. The element characteristics (sectional tangent stiffness matrix, element tangent stiffness matrix restoring forces) are directly derived from their symbolic expressions through numerical integration. In this way the same spatial grid allows us to obtain a non-local strain estimate and also to sample the contributions to the element stiffness matrix. Three examples show the spurious behaviors due to the strain localization and the stabilization effects given by the regularisation techniques, both in the case of tension and compression softening. The possibility to overestimate the ultimate load level when the non-local strain measure is applied to a non softening material is shown.

• Journal of information and communication convergence engineering
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• 제5권1호
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• pp.1-6
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• 2007

In the process of the acquisition, storage, transmission of signals, noises are generated by various causes and the degradation phenomenon by noises tends to generate serious errors for the signal with information. So, in order to analyze and remove these noises, studies on numerous mathematical methods such as the Fourier transform have been implemented. And recently there have been many ongoing wavelet-based denoising algorithms representing excellent characteristics in time-frequency localization and multiresolution analysis, but the method to remove additive white Gaussian noise (AWGN) and the impulse noise simultaneously was not given. So, to reconstruct the corrupted signal by noises, in this paper a novel wavelet-based denoising algorithm was proposed and using signal-to-noise ratio (SNR) this method was compared to conventional methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.107-111
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• 2005

It has been reviewed whether it would be suitable that the application of the time-frequency signal analysis techniques to estimate the location of the impact source in plate structure. The STFT(Short Time Fourier Transform), WVD(Wigner-Ville distribution) and CWT(Continuous Wavelet Transform) methods are introduced and the advantages and disadvantages of those methods are described by using a simulated signal component. The essential of the above proposed techniques is to separate the traveling waves in both time and frequency domains using the dispersion characteristics of the structural waves. These time-frequency methods are expected to be more useful than the conventional time domain analyses fer the impact localization problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the location estimation in a noisy environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4541-4554
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• 2019

This paper proposes a planar projection DV-hop location algorithm (PTCDV-hop) based on the LED semi-angle at half power (SAHP, which accounts for LED SAHP characteristics in visible light communication (VLC)) and uses the DV-hop algorithm for range-free localization. Distances between source nodes and nodes positioned in three-dimensional indoor space are projected onto a two-dimensional plane to reduce complexity. Circles are structured by assigning source nodes (projected onto the horizontal plane of the assigned nodes) to be centers and the projection distances as radii. The proposed PTCDV-hop algorithm then determines the position of node location coordinates using the trilateral-weighted-centroid algorithm. Simulation results show localization errors of the proposed algorithm are on the order of magnitude of a millimeter when three sources are used. The PTCDV-hop algorithm has higher positioning accuracy and stronger dominance than the traditional DV-hop algorithm.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.45-49
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• 2022

In this paper, we propose a method for estimating the error of the Ultra-Wideband (UWB) distance measurement using the channel impulse response (CIR) of the UWB signal based on machine learning. Due to the recent demand for indoor location-based services, wireless signal-based localization technologies are being studied, such as UWB, Wi-Fi, and Bluetooth. The constructive obstacles constituting the indoor environment make the distance measurement of UWB inaccurate, which lowers the indoor localization accuracy. Therefore, we apply machine learning to learn the characteristics of UWB signals and estimate the error of UWB distance measurements. In addition, the performance of the proposed algorithm is analyzed through experiments in an indoor environment composed of various walls.

• 디지털융복합연구
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• 제9권5호
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• pp.193-202
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• 2011

본 연구는 인천소재 국가 산업단지인 남동공단에 위치한 기업들의 클러스터 형성과 관련된 구성 요소와, 특성, 이들 특성요인이 클러스터에 분포한 기업성과에 미치는 영향을 분석하여 향후 혁신 클러스터 구축방향에 대한 대안제시를 목적으로 한다. 연구결과 성공한 클러스터 기업들의 특징은 클러스터 집약정도, 네트워킹의 정도, 집단학습, 혁신시너지, 국지화 등이 유의한 차이를 나타내는 것으로 나타났다. 또한 대기업과 중소기업간의 협력관계가 중요한 성패요인이며 이를 위해 공동연구개발이나 프로그램운영 등에 지원이 필요하다.

• 미생물학회지
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• 제32권2호
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• pp.139-146
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• 1994

Photobacterium leiognathi CuZuSOD(PSOD)의 부세포성 분포에 따른 방어효과가 paraquat, 열 쇼크, 과산화수소 그리고 $CuSO_4$의 처리시 각각 조사되었다. 서로 달리 periplasm내에 분포하는 PSOD와 세포질에 분포하는 PSOD 사이의 생리적 특성은 본 연구에서는 조건에 따란 차이를 보였다. Paraquat나 $H_2O_2$ 처리시에는 periplasm에 SOD를 발현하는 세포에서 세포질내에 SOD를 분포하는 경우보다 약간 방호효과가 나았으며 SOD 발현 정도는 이와 일관되게 아주 중요한 변화를 보였다. 그러나 열 쇼크와 $CuSO_4$의 처리시는 각각 이런 현상이 역으로 나타났다.

• 농촌지도와개발
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• 제5권1호
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• pp.103-112
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• 1998

This research was carried out to provide the information for the reorganization of County Extension system. In order to develop the extension system, basically we must understand the various characteristics of the extension organization such as farmer`s needs, community environments and its releated organizations. In respose to localization, county extension organization will be changed by the consderation its unique characteristics.