• 전기학회논문지
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• 제64권12호
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• pp.1742-1747
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• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.20-24
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• 2006

In this paper we investigated the method of examining the accelerated life test on LED traffic signal module by the temperature. The longevity presumption of the LED type signal light by a general heat cycle test used and executed cycle when it was done to longevity by the heat cycle test number and the acceleration factor of a real system requirements of this heat cycle test. Therefore, it reports on the introduction of the acceleration type from which the LED traffic signal module is done here to clarify the above-mentioned acceleration factor with the object and the acceleration factor is requested the test atmosphere actually in the system requirements.

• 디지털콘텐츠학회 논문지
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• 제18권4호
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• pp.621-629
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• 2017

인구구조의 고령화와 만성질환 환자 증가로 인한 빠른 의료비 지출 상승에 따라, 디지털 헬스케어 산업에 대한 관심도 높아지고 있다. 디지털 헬스케어는 기존 서비스의 이용자인 환자 외에 일반인까지 수요자 범위를 확장하였으며, 이에 따라 일반인의 디지털 헬스케어 이용현황 및 요구 파악에 대한 연구의 필요성이 증가하고 있다. 본 연구는 일반인 1,000명을 대상으로 인터넷 건강정보 서비스, 스마트폰 건강관리 애플리케이션, 웨어러블 디바이스, 유헬스 등 4개 부문에서 각각의 서비스 이용 경험, 이용 목적 및 보완점 등을 조사하고, 제공 받고 싶은 헬스케어 서비스 및 콘텐츠 유형, 이용 의사 등을 파악하였다. 본 연구 결과를 통하여 일반인들의 디지털 헬스에 대한 인식과 현재 서비스에 대한 만족도 및 미충족 서비스 요구를 파악함으로써 향후 디지털 헬스케어 서비스 개발에 도움이 될 수 있을 것이다.

• Earthquakes and Structures
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• 제3권5호
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• pp.675-694
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• 2012

The 2008 Iwate-Miyagi Nairiku earthquake ($M_w$ 6.9, $M_{jma}$ 7.2) occurred on 14 June 2008 in Japan. The amplification and asymmetric waveform of the vertical acceleration at the ground surface recorded by accelerometers at station IWTH25, situated 3 km from the source, were remarkable in two ways. First, the vertical acceleration was extremely large (PGA = 38.66 $m/s^2$ for the vertical component, PGA = 42.78 $m/s^2$ for the sum of the three components). Second, an unusual asymmetric waveform, which is too far above the zero acceleration axis, as well as large upward spikes were observed. Using a multidegree-of-freedom (MDF) system consisting of a one-dimensional continuum subjected to vertical acceleration recorded at a depth of 260 m below ground level, the present paper clarifies numerically that these singular phenomena in the surface vertical acceleration records occurred as a result of the jumping and collision of a layer in vertical motion. We herein propose a new mechanism for such jumping and collision of ground layers. The unexpected extensive landslides that occurred in the area around the epicenter are believed to have been produced by such jumping under the influence of vertical acceleration.

• 제어로봇시스템학회논문지
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• 제18권7호
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• pp.638-643
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• 2012

This paper presents an intelligent reduction method for external noise. The main idea comes from PSO-FCM (Particle Swam Optimization Fused fuzzy C-Means) clustering. The data of the target is transformed from the antenna coordinates to the vessel one and to the system coordinates. In the conversion, the overall noises hinder observer to get the exact position and velocity of the maneuvering target. While the filter is used for tracking system, unexpected acceleration becomes the main factor which makes the uncertainty. In this paper, the tracking efficiency is improved with the PSO-FCM and the compensation methodology. The acceleration is approximated from the external noise splitted by the proposed clustering method. After extracting the approximated acceleration, the rest in the noise is filtered by the filter and the compensation is added to after that. Proposed tracking method is applicable to the linear model and nonlinear one together. Also, it can do to the on-line system. Finally, some examples are provided to examine the reliability of the proposed method.

• 한국구조물진단유지관리공학회 논문집
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• 제24권6호
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• pp.161-170
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• 2020

본 연구에서는 공공 시설물을 대상으로 설치된 지진가속도 계측 시스템의 운영 효율성 개선을 위하여 지진 이벤트 신호 변환 및 처리 알고리즘을 개발하였다. 더불어 처리된 지진 가속도 시간이력의 분석을 통해 건축물의 안전성을 평가할 수 있는 평가 방법과 평가 기준을 제안하였으며, 테스트베드 건축물에 적용하여 그 작동과 활용성을 검증하였다. 이를 통해 지진 이벤트 계측자료의 분석 정확성을 확보하고, 지진재해 상황에서 재난 대응의 방향과 우선순위 판단을 위한 의사결정 지원자료로 활용할 수 있을 것으로 판단된다.

• ETRI Journal
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• 제39권4호
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• pp.525-534
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• 2017

A hardware-acceleration architecture that separates virtual network functions (VNFs) and network control (called HSN) is proposed to solve the mismatch between the simple flow steering requirements and strong packet processing abilities of software-defined networking (SDN) forwarding elements (FEs) in SDN/network function virtualization (NFV) architecture, while improving the efficiency of NFV infrastructure and the performance of network-intensive functions. HSN makes full use of FEs and accelerates VNFs through two mechanisms: (1) separation of traffic steering and packet processing in the FEs; (2) separation of SDN and NFV control in the FEs. Our HSN prototype, built on NetFPGA-10G, demonstrates that the processing performance can be greatly improved with only a small modification of the traditional SDN/NFV architecture.

• 대한기계학회논문집A
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• 제27권10호
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• pp.1712-1719
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• 2003

This paper concerns on application of active magnetic bearing(AMB) system to levitate the elevation axis of an electro-optical sight mounted on moving vehicles. In such a system, it is desirable to retain the elevation axis within the predetermined air-gap while the vehicle is moving. An optimal base acceleration feedforward control is proposed to reduce the base motion response. In the consideration of the uncertainty of the system model, a filtered-x least-mean-square(FXLMS) algorithm is used to estimate the frequency response function of the feedforward control which cancels base motions. The frequency response function is fitted to an optimal feedforward control. Experimental results demonstrate that the proposed control reduces the air-gap deviation to 27.7% that by feedback control alone.

• 센서학회지
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• 제16권6호
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• pp.467-474
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• 2007

The real-time monitoring about the activity of the human provides useful information about the activity quantity and ability. The present study implemented a small-size and low-power acceleration monitoring system for convenient monitoring of activity quantity and recognition of emergent situations such as falling during daily life. For the wireless transmission of acceleration sensor signal, we developed a wireless transmission system based on a wireless sensor network. In addition, we developed a program for storing and monitoring wirelessly transmitted signals on PC in real-time. The performance of the implemented system was evaluated by assessing the output characteristic of the system according to the change of posture, and parameters and acontext recognition algorithm were developed in order to monitor activity volume during daily life and to recognize emergent situations such as falling. In particular, recognition error in the sudden change of acceleration was minimized by the application of a falling correction algorithm

• 한국지능시스템학회논문지
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• 제5권4호
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• pp.101-110
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• 1995

본 연구에서는 직류 서보전동기의 위치, 속도 및 토오크 등의 제어기법중 외란에 대해 강인한 것으로 평가되고 있는 기존의 가속도 제어기법을 해석하고 그 결과 적용상의 문제점으로 판단되는 계통 파라미터 변화에 대한 강인성을 개선하기 위한 대책으로서 변경된 가속도제어 루프를 포함한 위치제어계를 제안하고 이를 직류전동기의 위치제어게 적용하였다. 제안된 제어계는 가속도제어기와 자기종조 퍼지 PID 제어기로 구성되어 있으며 제안된 제어계와 기존의 가속도제어계와의 근복적 차이점은 이 제어기법의 핵심 요소라 할 수 있는 가속도 기준입력 정정량의 발생기구로서 고전적 PID제어기를 자동조정하는 자기동조 PID 제어방식을 채택하였다는 점이다. 이 기준입력 발생기구를 도입한 직류전동기 위치제어계의 성능을 검토하기 위하여 그 응답특성을 기존의 가속도제어 위치제어계의 응답특성과 비교한 결과 파라미터 변화에 대한 강인성, 과도 특성 및 정상상태 특성면에서 제안된 제어계가 매우 우월한 성능을 가짐을 확인하였다. 따라서 제안된 제어기법은 기존의 가속도제어에 근거한 위치제어계의 성능을 개선시켜줌으로써 이 제어기법의 적용범위 확대에 기여하며 특히 모델의 불확정성이 크거나 부하등 운전환경이 크게 변화하는 악조건 하에서의 정밀한 위치제어에 적용될 수 있다.