• 센서학회지
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• 제29권5호
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• pp.279-282
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• 2020

In this study, body pressure was quantitatively detected using built-in optical sensors, inside an air cushion seat. The proposed system visualizes the effect of the body pressure distribution on the air cushion seat. The built-in sensor is based on the time-of-flight (ToF) optical method, instead of the conventional electrical sensor. A ToF optical sensors is attached to the bottom surface of the air-filled cells in the air cushion. Therefore, ToF sensors are durable, as they do not come in physical contact with the body even after repeated use. A ToF sensor indirectly expresses the body pressure by measuring the change in the height of the air-filled cell, after being subjected to the weight of the body. An array of such sensors can measure the body pressure distribution when the user sits on the air cushion seat. We implemented a prototype of the air cushion seat equipped with 7 ToF optical sensors and investigated its characteristics. In this experiment, the ToF optical pressure sensor successfully identified the pressure distribution corresponding to a sitting position. The data were accessed through a mobile device.

• 한국멀티미디어학회논문지
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• 제10권10호
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• pp.1260-1270
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• 2007

테스트 기술자들에게 아날로그 회로(또는 혼합신호 회로)의 테스트와 진단은 여전히 어려운 문제여서 이를 해결할 수 있는 효과적인 테스트 방법이 크게 요구된다. 본 논문에서는 time slot specification(TSS) 기반의 내장 전류감지기(Built-in Current Sensor)를 이용한 새로운 아날로그 회로의 테스트 기법을 제안한다. 또한 TSS에 기반 하여 고장 위치를 찾아내고 고장의 종류를 구별해 내는 방법을 제시한다. TSS 기법과 함께 제안하는 내장 전류감지기는 높은 고장 용이도와 높은 고장 검출을 그리고 아날로그 회로내 강고장과 약고장에 대한 높은 진단율을 갖는다. 제안하는 방법에서는 주출력과 전원단자등을 테스트 포인트로 사용하고 전류감지기를 자동 테스트 장치(Automatic Test Equipment)에 구성하므로써 테스트 포인트 선택과정의 복잡도를 줄일 수 있다. 내장 전류 감지기의 디지털 출력은 아날로그 IC 테스트를 위한 내장 디지털 테스트 모듈과 쉽게 연결된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.248-268
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• 2018

The performance of smartphone applications are usually constrained in user interactions due to resource limitation and it promises great opportunities to improve the performance by exploring the smartphone built-in and embedded sensing techniques. However, heterogeneity in techniques, semantic gap between sensor data and usable context, and complexity of contextual situations keep the techniques from seamless integration. Relevant studies mainly focus on feasibility demonstration of emerging sensing techniques, which rarely address both general architectures and comprehensive technical solutions. Based on a proposed functional model, this investigation provides a general architecture to deal with the dynamic context for context-aware automation and decision support. In order to take advantage of the built-in sensors to improve the performance of mobile applications, an ontology-based method is employed for context modelling, linguistic variables are used for heterogeneous context presentation, and semantic distance-based rule matching is employed to customise functions to the contextual situations. A case study on mobile application authentication is conducted with smartphone built-in hardware modules. The results demonstrate the feasibility of the proposed solutions and their effectiveness in improving operational efficiency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.163-164
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• 2007

In this study, we developed intelligent spacer built in the internal type UHF PD sensors. 3-Dimensional electro-magnetic simulations were performed to analyze electric-field distribution of the single-phase GIS and three-phase GIS. After considering the spacer's specification, Sensor structures were designed and analyzed using the 3-D EM Simulator. As a result of the simulation the internal type UHF PD sensors were built in. Performance of the sensor built into real scale GIS spacer was measured in terms of return loss and detected Max voltage. And we identified a character of the intelligent spacer by using 5pC partial discharge ceil.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.633-634
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• 2006

A new specification-based analog and mixed-signal test technique using high performance current sensors is proposed. The proposed technique using current sensors built in external ATE has little hardware overhead in circuit under test and high testability without time consuming operation of test point placement algorithm.

• 인터넷정보학회논문지
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• 제13권5호
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• pp.93-104
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• 2012

오늘날 사용하고 있는 네비게이션의 신뢰성은 기술적인 발전을 통해 상당히 높아졌다. GPS는 위성기반 위치추적 시스템으로 가장 광범위하게 사용되는 기술이다. 하지만 GPS기반 시스템은 위성이 정확한 뷰를 제공해줄 때에만 위치추적이 정확하다. 본 연구에서는 추적을 위해 내부구조에 의존하지 않는 독자적인 네비게이션을 제안한다. 스마트폰의 내장센서와 내장 맵을 사용하여 정확한 차량 위치추적을 구현한다. 성능평가 결과 정확한 차량의 위치 지원 면에서 우리가 제안한 시스템이 GPS보다 성능이 우수함을 나타내었다.

• 대한기계학회논문집
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• 제19권9호
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• pp.2082-2088
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• 1995

In this paper, we designed and fabricated the magnetic bearings and built-in type cylindrical capacitive transducers for improving the vibration characteristics of rotating shaft. The eddy current and magnetic field from the electromagnet of the bearing don't affect the measuring signal of the capacitive type transducers so that it is possible to locate the capacitive sensor plates around the magnetic bearing poles and can improve the spillover problem which is induced by the noncollocation of the sensors and actuators. According to the sensitivity calibration schemes using a X-Y table, the cylindrical capacitive transducers have a good linearities in the .+-.70.mu.m range from the geometric center of the sensor plates. The measured results also show high displacement sensitivities of the sensors. According to the performance test of the magnetic bearing which is controlled by the analog PD controllers, we found that the built-in capacitive transducer system successfully measures the journal displacement in the magnetic field and therefore the magnetic bearing system supports the rotating shaft up to 12,000 rpm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1378-1379
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• 2008

In this study, we developed intelligent spacer built in the internal type UHF PD sensors. 3-Dimensional electro-magnetic simulations were performed to analyze electric-field distribution of the single-phase GIS and three-phase GIS. After considering the spacer's specification, Sensor structures were designed and analyzed using the 3-D EM Simulator. As a result of the simulation the internal type UHF PD sensors were built in. Performance of the sensor built into real scale GIS spacer was measured in terms of return loss and detected Max voltage. And we identified a character of the intelligent spacer by using 5pC partial discharge cell.

• 한국공간구조학회논문집
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• 제19권2호
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• pp.63-72
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• 2019

Wireless sensors are more favorable in measuring structural response compared to conventional sensors in terms of them being easier to use with no issues with cables and them being considerably cheaper. Previous tests have been conducted to analyze the performance of MEMS (Micro Electro Mechanical Systems) sensor in sinusoidal excitation tests. This paper analyzes the performance of in-built MEMS sensors in devices by comparing with an ICP sensor as the reference. Earthquake input amplitude excitation in shaking table tests was done. Results show that MEMS sensors are more accurate in measuring higher input amplitude measurements which range from 100gal to 250gal than at lower input amplitudes which range from 10gal to 50gal. This confirms the results obtained in previous sinusoidal tests. It was also seen that natural frequency results have lower error values which range from 0% to 3.92% in comparison to the response spectra results. This also confirms that in-built MEMS sensors in mobile devices are good at estimating natural frequency of structures. In addition, it was also seen that earthquake input amplitudes with more frequency contents (Gyeongju) had considerably higher error values than Pohang excitation tests which has less frequency contents.

• Journal of the Optical Society of Korea
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• 제11권4호
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• pp.177-182
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• 2007

This paper discusses the errors associated with electric field cross talk for optical voltage sensors in a three-phase electric system and provides a solution to compensate the errors. For many practical conductor configurations, the electric field cross talk may cause errors unacceptable for the accuracy requirements of the sensors. We devised a real time compensation method for the cross talk and built an electronic circuits based on it. The mechanism of the compensation and the corresponding error reduction were discussed.