• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.2961-2975
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• 2022

The Location-Based Service (LBS) is one of the most well-known services on the Internet. Positioning is the primary association with LBS services. This study proposes an intelligent LoRa-based positioning system, called AI@LBS, to provide accurate location data. The fingerprint mechanism with the clustering algorithm in unsupervised learning filters out signal noise and improves computing stability and accuracy. In this study, data noise is filtered using the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) algorithm, increasing the positioning accuracy from 95.37% to 97.38%. The problem of data imbalance is addressed using the SMOTE (Synthetic Minority Over-sampling Technique) technique, increasing the positioning accuracy from 97.38% to 99.17%. A field test in the NTUST campus (www.ntust.edu.tw) revealed that AI@LBS system can reduce average distance error to 0.48m.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.137-144
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• 2006

This paper proposes novel protection schemes for grid-connected distributed generation (DG) units using the fault location algorithm. The grid-connected DG would be influenced by abnormal distribution line conditions. Identification of the fault location for the distribution lines at the relaying point of DG helps solve the problems of the protection relays for DG. The proposed scheme first identifies fault locations using currents and voltages measured at DG and source impedance of distribution networks. Then the actual faulted feeder is identified, applying time-current characteristic curves (TCC) of overcurrent relay (OCR). The method considering the fault location and TCC of OCR might improve the performance of the conventional relays for DG. Test results show that the method prevents the superfluous operations of protection devices by discriminating the faulted feeder, whether it is a distribution line where DG is integrated or out of the line emanated from the substation to which the DGs are connected.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.116-120
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• 2001

Fiber fracture is one of the dominant failure phenomena to determine total mechanical properties in composites. Fiber fracture locations were measured by optical microscopic method and acoustic emission (AE) as functions of matrix toughness and surface treatment by the electrodeposition (ED), and then two methods were compared. Two AE sensors were attached on the epoxy specimen and fiber fracture signals were detected with elapsed time. The interfacial shear stress (IFSS) was measured using tensile fragmentation test and AE system. In ED-treated case, the number of the fiber fracture measured by an optical method and AE was more than that of the untreated case. The signal number measured by AE were rather smaller than the number of fragments measured by optical method, since some fiber fracture signals were lost while AE detection. However, one-to-one correspondence between the x-position location by AE and real break positions by optical method was generally established well. The fiber break source location using AE can be a valuable method to measure IFSS for semi- or nontransparent matrix composites nondestructively (NDT).

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.359-367
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• 2020

IoT(Internet of Things)의 주요기술인 WSNs(Wireless Sensor Networks)는 위치를 기반으로 정보를 전달하거나 인증을 하는 경우가 많기에 잘못된 위치 정보는 서비스에 큰 위험이 된다. 따라서 위치 정보를 검증하는 방법은 필수적이다. 목적에 적합한 기법을 설계하기 위해서는 기존 연구들에 대한 통합적인 분석과 분류 결과가 중요하다. 본 논문은 WSN 를 대상으로 개발된 위치 검증 기법들의 특징에 대해 통합적인 분석 및 분류 결과를 제시하는 것을 목표로 한다. 이를 위해 기발표된 주요 위치 검증 기법들의 특징 분석 결과를 바탕으로 분류 기준을 설정한다. 그리고 설정한 분류 기준에 따라 기존 연구 결과를 분류하고 각각의 특징과 발전 방향을 기술한다. 본 논문의 결과는 기존의 위치 검증 기법 분석 및 분류 연구와 비교해, 보다 다양한 기준을 제시하고 있다는 점에서 신규 기법의 설계시 유용한 참고자료가 될 것으로 기대된다.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1754-1763
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• 2017

This paper analyses the characteristics of incomplete-journey double-circuit transmission lines on the same tower formed by single-circuit lines and double-circuit lines, and then presents a fault location algorithm based on identification of fault branch. With the relationship between the three-phase system and the double-circuit line system, a phase-mode transformation matrix for double-circuit lines can be derived. Based on the derived matrix, the double-circuit lines with faults can be decoupled, and then the fault location for an incomplete-journey double-circuit line is achieved by using modal components in the mode domain. The algorithm is divided into two steps. Firstly, the fault branch is identified by comparing the relationships of voltage amplitudes at the bonding point. Then the fault location, on the basis of the identification result, is calculated by using a two-terminal method, and only the fault distance of the actual fault branch can be obtained. There is no limit on synchronization of each terminal sampling data. The results of ATP-EMTP simulation show that the proposed algorithm can be applied within the entire line and can accurately locate faults in different fault types, fault resistances, and fault distances.

• 한국인터넷방송통신학회논문지
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• 제19권6호
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• pp.133-138
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• 2019

현대 사회에서 급부상한 분야의 대표적인 하나가 SNS이고, 최근 각광을 받고 있는 기술이 AR 기술이다. 본 논문에서는 SNS에 AR기술을 접목하여, 새로운 형태의 커뮤니티 기능을 제공하고 관련 기술을 개발하고자 한다. 본 논문에서 개발한 시스템은 현재 위치에서 AR 메시지 띄우기, AR을 이용한 길 찾기 등 위치정보와 AR을 응용한 커뮤니티 기능들을 제공하여 사용자들간의 차별화된 소통을 제공한다. 뿐만 아니라, 본 논문은 위치 정보 기반 증강현실 구현을 위해 필수적인 지도정보를 얻기 위한 방법으로 기존 지도 API의 특성을 고려하여 기존 지도 API 활용 방법을 제시한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.278-279
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• 2015

최근, 스마트 기기의 발전과 더불어 스마트 단말을 이용한 지능형 실내 위치 인식 서비스에 대한 관심이 증대되고 있다. 이때 실내 위치 측위 기술로서 BLE(Bluetooth Low Energy) 기술이 관심을 받고 있다. 그러나 방대한 위치 정보를 수신하는 스마트 단말에서 수집된 위치 정보의 신뢰성을 확인할 수 있는 방법은 없다. 이는 신호 간섭 등의 이유로 실내 위치 정보의 신뢰성가 떨어지기 때문이다. 본 논문에서는 iBeacon의 위치 정보로 부터 신뢰성 있는 위치 정보를 얻기 위해 수집된 빅 데이터의 관리 기법을 제안한다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1807-1813
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• 2018

In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.

• 대한원격탐사학회지
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• 제23권5호
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• pp.465-471
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• 2007

Many hospitals have been considering new technology such as wireless sensor network(WSN). The technology can be used to track the location of medical devices needed for inspections or repairs, and it can also be used to detect of a theft of an asset. In an asset-tracking system using WSN, acquiring the location of moving sensor nodes inherently introduces uncertainty in location determination. In fact, the sensor nodes attached to an asset are prone to failure from lack of energy or from physical destruction. Therefore, even if the asset is located within the predetermined area, the asset-tracking application could "misunderstand" that an asset has escaped from the area. This paper classifies the causes of such unexpected situations into the following five cases: 1) an asset has actually escaped from a predetermined area; 2) a sensor node was broken; 3) the battery for the sensor node was totally discharged; 4) an asset went into a shadow area; 5) a sensor node was stolen. We implemented and installed our asset-tracking system in a hospital and continuously monitored the status of assets such as ventilators, syringe pumps, wheel chairs and IV poles. Based on this real experience, we suggest how to differentiate each case of location uncertainty and propose possible solutions to prevent them.