• 문화기술의 융합
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• 제8권2호
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• pp.355-360
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• 2022

본 연구에서는 마이크로 데이터 센터의 환경 모니터링 시스템(EMS)을 설계하고 개발하는 방법을 나타낸다. 설계하는 환경 모니터링 시스템은 IoT 센서 및 싱글보드 컴퓨터를 이용하여 데이터센터 운영환경을 실시간으로 감지하여 데이터를 해석하고 운영환경을 모니터한다. 먼저, EMS 하드웨어 플랫폼 및 IoT 센싱 패키지 설계 방법에 대하여 나타낸다. 또한 서로 다른 프로토콜을 갖는 IoT 센서에 대한 데이터 수집 SW을 설계하고 원격에서 모니터링이 가능한 EMS 모니터링 SW를 개발한다. 데이터 수집 SW는 센서 수집 모듈과 수집 메니저 모듈로 구성된다. EMS 소프트웨어는 마이크로 서비스 아키텍츠(MSA) 개념을 적용하여 설계하며 각각의 서비스는 독립적인 비즈니스 로직을 포함한다.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1328-1334
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• 2015

A new system for evaluating the voltage management errors of distribution equipment is presented in this paper. The main concept of the new system is to use real distribution live-line voltage to evaluate and correct the voltage measurement data from distribution equipment. This new approach is suitable for a new Distribution Management System (DMS) which has been developed for a distribution power system due to the connection of distributed generation growth. The data from distribution equipment that is installed at distribution lines must be accurate for the performance of the DMS. The proposed system is expected to provide a solution for voltage measurement accuracy assessment for the reliable and efficient operation of the DMS. An experimental study on actual distribution equipment verifies that this voltage measurement accuracy assessment system can assess and calibrate the voltage measurement data from distribution equipment installed at the distribution line.

• 조명전기설비학회논문지
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• 제27권9호
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• pp.83-89
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• 2013

Power distribution system has been changed from radial system to closed loop or mesh system due to connection of distributed generation growth. Data from distribution equipments which are installed at distribution line is required to be accurate for the performance of DMS(Distribution Management System). This paper analyzes the voltage measurement data from distribution equipment. However, the results of the analysis are confirmed to have some errors in voltage measurement data from distribution equipment. These errors come from aging of voltage sensor in distribution equipment and inaccurate data transfer to FRTU(feeder remote terminal unit) through the controller. The main problem is that the voltage measurement data of distribution equipment can not be assessed after it's first installation at the distribution line. The voltage measurement accuracy assessment system is to assess the voltage measurement data from distribution equipment on hot-line. This study had a field test to verify the performance of system.

• 핵의학기술
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• 제13권1호
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• pp.51-56
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• 2009

목적 : Small-scalled PACS, Pc-based PACS로 표현되는 MicroPACS 시스템 구축에 대한 관심도가 급격하게 증가하고 있는 추세이다. MicroPACS 시스템은 PACS를 작은 규모에서 사용할 수 있도록 구성해놓은 것이고, 이 시스템을 구성하기 위해서는 DICOM viewer나 연결프로그램 등이 필요하다. 이것은 공개소스프로그램(Open Source Program)을 통해서 어느 누구나 쉽게 무료로 다운로드를 받을 수 있게 되어있다. 본 논문은 Open source program으로 MicroPACS를 직접 구성해보았고, 저장매체로서의 활용가치를 측정하기위하여 성능, 안정성 측면에서 기존의 광 저장매체(CD, DVDRAM)와 비교 분석하였다. 실험재료 및 방법 : 1. 소형 PACS를 구축하기 위해서 먼저 다음 기준에 맞는 DICOM Server Software를 검색한다. (1) 윈도우체제에서 사용가능할 것. (2) Free ware일 것. (3) PET/CT scanner와 호환되어야 할 것. (4) 사용하기 쉬워야 할 것. (5) 저장의 한계가 없어야 할 것. 2. (1) MicroPACS의 성능을 평가하기 위해 환자 1명의 Data ($^{18}F$-FDG Torso PET/CT)를 현재 Back-up장치로 쓰이는 광 저장매체(CD, DVD-RAM)와 MicroPACS에 저장하는데 소요되는 시간(Back up time)과 workstation으로 복구되기까지의 시간(Retrieval time)을 비교해 보았다. (2) PET/CT 검사를 시행했던 환자 1명의 병록번호와 검사 시행날짜를 핵의학과 직원 7명을 대상으로 알려주고 Data를 찾는데 소요되는 시간을 MicroPACS와 광 저장매체(CD, DVD-RAM)에서 각각 측정하여 비교하였다. 3. 기존의 백업장치로 쓰였던 CD들 중에서 2004년부터 2006년까지 500장을 무작위로 뽑아서 loading을 하였고 그중에서 얼마만큼의 에러가 발생하였는지를 측정하여 MicroPACS의 안정성을 비교평가하였다. 결과 : 1. Server와 DICOM viewer 기능을 갖춘 11개의 open source software 중에서 Conquest DICOM Server를 선택하였다. 2. (1) Backup과 Retrieval 시간 비교(단위 : 분)는 다음과 같다; DVD-RAM(5.13,2.26)/Conquest DICOM Server (1.49,1.19) by GE DSTE (p<0.001), CD (6.12,3.61)/Conquest (0.82,2.23) by GE DLS (p<0.001), CD (5.88,3.25)/Conquest (1.05,2.06) by SIEMENS. (2) CD ($156{\pm}46$초), DVD-RAM ($115{\pm}21$초) and Conquest DICOM Server ($13{\pm}6$초). 3. 1년간 MicroPACS에서의 데이터손실은 없었으며(0%), 500장의 CD 중에서 14개(2.8%)가 Loading하는데 실패하였다. 결론 : 현재 많은 병원에서 도입되고 있는 Full PACS를 open source software를 통하여 소규모의 PACS로 재현해 보았고, 그 결과 가능하다는 결론이 나왔다. 데이터 저장의 유용성을 평가한 결과에서 MicroPACS를 이용하는 것이 기존의 광저장매체를 사용하는 것보다 효율적이고 작업속도가 향상 된다는 것을 확인할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1655-1658
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• 2004

In this paper, we design and implement remote servo motor control system with real-time micro embedded operating system. The system, where controller and camera image grabber are mounted, handles control commands transmitted from a remote PC web browser. A hard real-time servo motor driver running on the real-time micro embedded OS and then a digital control application which confirms precise sampling time intervals is constructed. Frame grabber images transmitted from camera are saved in a image data format to view on remote PC web browser.

• Transactions on Electrical and Electronic Materials
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• 제3권1호
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• pp.30-37
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• 2002

A focusing grating coupler (FGC) was not fabricated by the 'Continuous Path Control'writing strategy but by an electron-beam lithography system of more general exposure mode, which matches not only the address grid with the grating period but also an integer multiple of the address grid resolution (5 nm). To more simplify the fabrication, we are able to reduce a process step without large decrease of pattern quality by excluding a conducting material or layer such as metal (Al, Cr, Au), which are deposited on top or bottom of an e-beam resist to prevent charge build-up during e-beam exposure. A grating pitch period and an aperture feature size of the FGC designed and fabricated by e-beam lithography and reactive ion etching were ranged over 384.3 nm to 448.2 nm, and 0.5 $\times$ 0.5 mm$^2$area, respectively. This fabrication method presented will reduce processing time and improve the grating quality by means of a consideration of the address grid resolution, grating direction, pitch size and shapes when exposing. Here our investigations concentrate on the design and efficient fabrication results of the FGC for coupling from slab waveguide to a spot in free space.

• 한국정밀공학회지
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• 제33권11호
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• pp.905-910
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• 2016

Infrared (IR) optic lens can be fabricated by a single point diamond turning (SPDT) machine without subsequent polishing process. However, this machining process often leaves micro-cracks that deteriorate the surface quality. In this work, we propose an experimental design to remove micro-cracks on IR lens. The proposed design gathered data between cutting process condition and Rt surface roughness. This is of great importance because the scale of micro-cracks is a few micrometer. Rt surface roughness is suitable for analyzing maximum peak height signals of the profile. The experimental results indicate that feed per revolution variable is one of the most dominant variable, affecting the generation micro-cracks on IR lens surfaces.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3687-3690
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• 2014

MicroRNA 200c is a microRNA 200 family member that plays an important role in regulation of the epithelial-to-mesenchymal transition (EMT). The prognostic value of microRNA 200c in solid tumors remains controversial because of inconsistent data. Here, we report a meta-analysis of the association of microRNA 200c expression and survival in patients with solid tumors. Pubmed was searched up to November 2013 for studies investigating microRNA 200c expression and overall survival (OS) in solid tumors. Hazard ratios (HRs) with 95% confidence intervals (CIs) for OS were extracted from each study. Pooled HR and CIs were calculated using the Mantel-Haenszel fixed-effects models. A total of five studies evaluating colorectal cancer, gastric cancer, ovarian cancer, pancreatic cancer and endometrial cancer were included in the analysis. Data were divided into tissue microRNA 200c expression group and serum microRNA 200c expression group. The combined HRs [95%CIs] estimated for OS were 0.62 [0.42-0.91] and 2.16 [1.32-3.52] respectively. Low expression of microRNA 200c in tumor tissue and high expression of microRNA 200c in serum are associated with worse survival in solid tumors. Further study is needed to elucidate this contradiction.

• 융합보안논문지
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• 제15권2호
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• pp.63-68
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• 2015

현재의 ICT 인프라(인터넷과 서버/Client 연동)는 다양한 장치, 서비스, 비즈니스 및 기술 진화에 따른 신속한 대응에 어려움을 겪고 있다. 클라우드 컴퓨팅(Cloud Computing)은 구름 같은 네트워크 환경에서 원하는 작업을 요청하여 실행한다는 데서 기원하였으며, 인터넷 기술을 활용하여 IT 자원을 서비스로 제공하는 컴퓨팅을 뜻하고 오늘날 IT 트렌드의 하나로 가장 주목 받고 있다. 이러한 분산클라우드 환경에서는 네트워크 및 컴퓨팅 자원에 대한 통합 관리 체계를 통하여 관리 비용 증가 문제를 원천적으로 해결하고 분산된 마이크로 데이터센터(Micro DC(Data Center))를 통하여 코어 네트워크 트래픽 폭증 문제를 해결하여 비용 절감 효과를 높일 수 있다. 그러나 기존의 Flooding 방식은 인접한 모든 DC들에게 전송하기 때문에 많은 트래픽을 유발 할 수 있다. 이를 위해 Restricted Path Flooding 알고리즘이 제안되었으나 대규모 네트워크에서는 여전히 트래픽을 발생할 수 있는 단점이 있어서 본 논문에서는 홉수 제한을 통하여 이를 개선한 Lightweight Path Flooding 알고리즘을 제안하였다.

• 대기
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• 제30권4호
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• pp.335-346
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• 2020

Three free parameters included in a cumulus parameterization are optimized by using micro-genetic algorithm for three precipitation cases occurred in the Korea Peninsula during the summer season in order to reduce biases in a regional model associated with the uncertainties of the parameters and thus to improve the predictability of precipitation. The first parameter is the one that determines the threshold in convective trigger condition. The second parameter is the one that determines boundary layer forcing in convective closure. Finally, the third parameter is the one used in calculating conversion parameter determining the fraction of condensate converted to convective precipitation. Optimized parameters reduce the occurrence of convections by suppressing the trigger of convection. The reduced convection occurrence decreases light precipitation but increases heavy precipitation. The sensitivity experiments are conducted to examine the effects of the optimized parameters on the predictability of precipitation. The predictability of precipitation is the best when the three optimized parameters are applied to the parameterization at the same time. The first parameter most dominantly affects the predictability of precipitation. Short-range forecasts for July 2018 are also conducted to statistically assess the precipitation predictability. It is found that the predictability of precipitation is consistently improved with the optimized parameters.