• 한국도서관정보학회지
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• 제30권2호
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• pp.199-233
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• 1999

본 연구의 목적은 공공도서관에서 수행하는 비디오자료의 선정 및 수집과 실제 이용현황을 조사하여 그 결과를 분석하여 앞으로 공공도서관 자료로서의 비디오자료의 체계적인 수집과 이용을 활성화하는 방안을 마련하고자 한 것이다. 이를 위하여 부산지역의 공공도서관 17개판(교육부 산하 12개관, 행정자치부 산하 5개관)을 대상으로 설문지기법을 사용하여 비디오자료의 수집과 이용현황을 조사하였다. 그 결과를 분석하여 문제점을 확인하고 그에 따른 개선 및 활성화 방안을 제시하였다.

• International Journal of Aeronautical and Space Sciences
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• 제10권2호
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• pp.86-94
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• 2009

This paper deals with the creation of a new, low-cost point/position tracking system that can measure deformations in engineering structures with simple commercially widespread cameras. Though point tracking systems do exist today, such as Stereo Pattern Recognition (SPR) and Projection Moir$\acute{e}$ Interferometry (PMI) systems, they are far too costly to use to analyze small, simple structures because complex optical components such as large flashes, high-resolution cameras and data acquisition systems with several computers are required. We developed a point tracking system using commercial cameras. This system used IR LEDs and commercial IR CCD cameras to minimize the interference posed by other extraneous light sources. The main algorithm used for this system is an optical point tracking algorithm, which is composed of the point extraction algorithm and the point matching algorithm for 3-D motion estimation. a series of verification tests were performed. Then, the developed point tracking system was applied to measure deformations of an acrylic plate under a mechanical load. The measured deformations of the acrylic plate matched well with the numerical analysis results. The results indicate that the developed point tracking system is reliable enough to measure continuous deformed shapes of various engineering structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.38-40
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• 2005

Microdrive with high precision and light mass enough to install on mouse head was fabricated for recording the reliable signal of neuron cell to understand the brain study. The proposed microdrive has three H-form PZT actuators and its guide structure. The microdrive operation principle is based on the well known inchworm principle. The synchronization of three PZT actuators is able to produce the linear motion along the guide structure. Our proposed microdrive has a precise accuracy of about 100nm and a long stroke of about 5mm. The electrode which is used for the recording of the action potential of the neuron cell was fixed at one of PZT actuators. The proposed microdrive was suited to acquisition of signals from in vivo extra-cellular single-unit recoding. On the condition of the anesthetized mouse, the single-unit signals could be recorded by using the proposed microdrive. In addition, applying the PZT microdrive to an alert mouse, we try to implant it on a mouse brain skull to explore single neuron firing.

• 한국소음진동공학회논문집
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• 제16권7호
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• pp.704-711
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• 2006

Vibration test on MAST(multi axial simulation table) system has several advantage over one-axial vibration test that could simulate 6-DOF, 3-axial translation and 3-axial moment, at the same time. Since field vibration motion can be fully represented with 6-DOF, multi-axial vibration test on vehicle component is widely conducted in technical leading companies to make sure its fatigue performance in vibration environment. On the way to fulfill the process, editing technique of obtained field data is key issue to success a reliable vibration testing with MAST system. Since the original signals are not only too large to fulfill it directly, but all of the measured data is not guarantee its convergency on generating its driving files, editing technique of the original signals are highly required to make some events that should meet the equal fatigue damage on the target component In this paper, key technique on editing a field data feasible for MAST system is described based on energy method in vibration fatigue. To explain its technique explicitly, author first introduced a process on field data acquisition of two vehicle component and then, representing events are produced to keep up with the editing strategy about a energy method. In the final chapter, a time information regarding a vibration test on MAST system is derived from the energy data which is critical information to perform a vibration test.

• 전기전자학회논문지
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• 제10권1호
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• pp.55-61
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• 2006

현대 사회는 의료 기술의 발달로 인한 인간 수명의 연장과 핵가족화로 인하여 혼자 지내는 노인이 많아지면서 응급상황 발생시 신속한 의료서비스를 받지 못하는 경우가 많아지고 있다. 또한 대표적인 성인병인 심혈관질환과 뇌졸중 그리고 노인의 건강에 치명적인 낙상의 발생율도 높아지고 있는 추세이다. 본 논문에서는 심전도, 체온, 사용자의 움직임 등의 생체신호를 획득하고 획득된 생체신호를 분석하여 심혈관질환, 뇌졸중, 낙상 등의 응급상황 발생시 응급의료센터와 보호자에게 구조메시지를 전송할 수 있는 시스템을 제안하였다. 시스템은 크게 생체신호 획득부와 모바일부 두 부분으로 나눌 수 있다. 생체신호 획득부는 사용자에 따라 생체신호의 추가, 제거가 어렵다는 단점을 보완하기 위해 심전도, 체온, 가속도 센서 모듈로 모듈화 하여 구성하였다. 모바일부는 생체신호 획득부로부터 전송된 생체신호의 처리 및 응급상황시 메시지 전송, 생체신호의 디스플레이 역할을 수행하며, 생체신호 획득부에서 획득된 생체신호는 블루투스 모뎀을 통하여 모바일부로 전송된다. 또한 모바일부에서 처리된 신호는 802.11b 무선랜을 통하여 PC로 전송된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.499-500
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• 2006

The electrode wear in micro-EDM significantly deteriorates the machining accuracy. In this regard, electrode wear needs to be compensated in-process to improve the product quality. Therefore, there are substantial amount of research about electrode wear. In this study a control method for micro-EDM using discharge pulse counting is proposed. The method is based on the assumption that the removed workpiece volume is proportional to the number of discharge pulses, which is verified from experimental results analyzing geometrically machined volume according to various number of discharges. Especially, the method has an advantage that electrode wear does not need to be concerned. The proposed method is implemented to an actual micro-EDM system using high speed data acquisition board, simple counting algorithm with 3 axis motion system. As a result, it is demonstrated that the volume of hole machined by EDM drilling can be accurately estimated using the number of discharge pulses. In EDM milling process a micro groove without depth variation caused by electrode wear could be machined using the developed control method. Consequently, it is shown that machining accuracy in drilling and milling processes can be improved by using process control based on the number of discharge pulses.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.764-769
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• 2006

Vibration test on MAST(multi axial simulation table) system has several advantage over one-axial vibration test that could simulate 6-DOF, 3-axial translation and 3-axial moment, at the same time. Since field vibration motion can be fully represented with 6-DOF, multi-axial vibration test on vehicle component is widely conducted in technical leading companies to make sure its fatigue performance in vibration environment. On the way to fulfill the process, editing technique of obtained field data is key issue to success a reliable vibration testing with MAST system. Since the original signals are not only too large to fulfill it directly, but all of the measured data is not guarantee its convergency on generating its driving files, editing technique of the original signals are highly required to make some events that should meet the equal fatigue damage on the target component In this paper, key technique on editing a field data feasible for MAST system is described based on energy method in vibration fatigue. To explain its technique explicitly, author first introduced a process on field data acquisition of two vehicle component and then, representing events are produced to keep up with the editing strategy about a energy method. In the final chapter, a time information regarding a vibration test on MAST system is derived from the energy data which is critical information to perform a vibration test.

• 한국정보통신학회논문지
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• 제22권10호
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• pp.1327-1333
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• 2018

수치 해석은 유동 경로를 공식화할 필요가 없다는 장점으로 경로 설계와 같은 시뮬레이션 분석에 유용하다. 그러나 유체의 완전한 물리적 매개 변수와 경계 조건을 알고 있어야 한다. 그중 하나라도 알 수 없는 경우, 계산이 불가능해 지거나, 수렴되더라도 결과의 신뢰성이 낮아진다. 따라서 유동 정보를 보다 정확하게 획득하는 방법이 요구된다. 본 논문은 수로 내의 염료의 이동에 수반되는 영상 명도의 변화를 기반으로 영상 정보 및 속도장의 구속식을 이용하여 염료의 속도장을 추정하는 기법을 제시한다. 구속식은 속도장 추정 시에 발생하는 오류를 최소화하기 위해서 안정화 항을 추가했다. 본 논문은 카르만 와류의 생성 이미지와 실제 영상을 대상으로 제안 수법의 효율성을 보인다.

• 한국전산구조공학회논문집
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• 제32권1호
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• pp.29-35
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• 2019

본 논문에서는 건축물 진동저감장치에 적용되는 액체감쇠기 내 유체 자유표면의 동적 거동 계측을 위해 저가형 RGB-depth 센서인 Microsoft사 $Kinect^{(R)}$ v2의 활용과 계측시스템을 구축하는 방법을 제안하였다. $Kinect^{(R)}$ v2의 성능검토 및 실효성 확인, SDK(software development kit)를 사용한 실시간 모니터링, 3D 공간상에서 유체의 표면 정보 취득, 기존 비디오 센싱기법과의 비교를 통해 본 연구에서 제안한 유체의 동적 거동 계측 시스템의 정확성과 우수성을 검증하였다. 제안된 계측시스템을 활용하여 소형 수조 내 액체에 대한 동적 거동 정밀계측을 수행하였으며, 이를 바탕으로 광범위한 가진입력에 대한 유체 자유표면의 동적 거동 특징을 확인하였다. 본 연구의 결과를 바탕으로 RGB-depth센서의 건축물 진동저감 적용을 통해 정밀한 모니터링 시스템을 구축하고 최적화된 액체감쇠기의 설계 및 운용을 기대할 수 있다.

• Investigative Magnetic Resonance Imaging
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• 제23권3호
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• pp.202-209
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• 2019

Purpose: To investigate the temperature-based differences of cortical bone ultrashort echo time MRI (UTE-MRI) biomarkers between body and room temperatures. Investigations of ex vivo UTE-MRI techniques were performed mostly at room temperature however, it is noted that the MRI properties of cortical bone may differ in vivo due to the higher temperature which exists as a condition in the live body. Materials and Methods: Cortical bone specimens from fourteen donors ($63{\pm}21$ years old, 6 females and 8 males) were scanned on a 3T clinical scanner at body and room temperatures to perform T1, $T2^*$, inversion recovery UTE (IR-UTE) $T2^*$ measurements, and two-pool magnetization transfer (MT) modeling. Results: Single-component $T2^*$, $IR-T2^*$, short and long component $T2^*s$ from bi-component analysis, and T1 showed significantly higher values while the noted macromolecular fraction (MMF) from MT modeling showed significantly lower values at body temperature, as compared with room temperature. However, it is noted that the short component fraction (Frac1) showed higher values at body temperature. Conclusion: This study highlights the need for careful consideration of the temperature effects on MRI measurements, before extending a conclusion from ex vivo studies on cortical bone specimens to clinical in vivo studies. It is noted that the increased relaxation times at higher temperature was most likely due to an increased molecular motion. The T1 increase for the studied human bone specimens was noted as being significantly higher than the previously reported values for bovine cortical bone. The prevailing discipline notes that the increased relaxation times of the bound water likely resulted in a lower signal loss during data acquisition, which led to the incidence of a higher Frac1 at body temperature.