데이터센터의 설비 통합 모니터링 시스템 설계에 관한 연구

최우형,황현숙,김창수,Choi, Woo-Hyoung,Hwang, Hyun-Suk,Kim, Chang-Soo 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.4

최근 클라우드 빅데이터에 대한 요구와 필요성이 나타나면서 대규모 데이터센터는 물론 공장 단위의 데이터센터 구축도 활기를 띠고 있다. 본 연구에서는 공장이나 중견 그룹의 데이터센터 구축시 다양한 설비들을 통합 관리할 수 있는 시스템 설계에 초점을 두고 있다. 중규모 그룹의 통합 설비들은 다양한 센서와 장치들이 관리되어야 되기 때문에 이들을 총체적으로 관리할 수 있는 통합 모니터링 시스템이 필요하다. 이를 위해서 본 연구에서는 통합 감시 시스템에서 관리되어야 할 다양한 설비들의 통합 모델 인터페이스 구성은 물론 데이터센터의 환경 설비에 대한 통합 모니터링 시스템을 제안하고, 이를 위한 표준의 수립 및 시스템 구축 공사 설계 시 발생할 수 있는 오류를 방지하고 수행 할 수 있는 방안을 제시한다. 그리고 통합 모니터링 시스템의 효율성 분석과 평가를 위한 장애 정보 전달 시간 분석 및 통합 시나리오를 제공한다. Recently, as shown demands and the need for Cloud dig data, large-scale data centers, as well as factory unit's have also vigor. This study focuses the system design that can integrate various facilities on the data center build upon of the factory and the midsize group. Because the integrated facilities management of midsize groups should have variety of sensors and devices requires integrated monitoring system that can manage them as a whole. In this study, it constitutes a integrated model protocol interface of the various facilities, it suggests ways to avoid the errors that may occur during design to study the development and systematically carried out. For this purpose, this study provides the analysis of a failure information delivery time and integration scenario for efficient analysis and evaluation of an integrated monitoring system.

위너필터를 사용한 파일럿 신호 추정 기반 ATSC 신호 감지

최우형(Woo-Hyoung Choi),이승준(Seung Joon Lee) 한국정보기술학회 2013 한국정보기술학회논문지 Vol.11 No.6

Technologies of cognitive radio with TV white space have been standardized in IEEE 802.22WRAN. Several algorithms have been developed for sensing digital TV ATSC signal which is one of primary user signals in TV white space. In this paper, we propose a method for improving the performance of pilot signal-based conventional sensing algorithms. The ATSC signal includes the pilot signal in the form of a sine wave with the frequency of 2.69 MHz. We designed a Wiener filter using the information of the pilot signal such as frequency and signal form, etc. Using the Wiener filter, we estimate the pilot signal of the ATSC signal buried in noise, so that the estimated signal looks more similar to a noise-free primary signal. If we use the estimated signal, then the pilot location sensing method and the correlation coefficient and skewness-based sensing method are shown by computer simulations to have a detection performance gain of 1.5dB compared to the case of using a raw (not preprocessed by a Wiener filter) inputsignal.

지적장애인의 중등 이후 교육 프로그램 평가도구 개발

최우형 ( Woo Hyoung Choi ),박정식 ( Jung Sik Park ) 한국지적장애교육학회(구 한국정신지체아교육학회) 2015 지적장애연구 Vol.17 No.2

본 연구는 지적장애인을 대상으로 하는 중등 이후 교육 프로그램 평가 도구 개발을 위하여 탐색적 요인 분석 및 2차례에 걸친 델파이 조사를 실시하였다. 탐색적 요인 분석의 대상으로서 서울, 경기지역의 중등교사 중 표시과목이 직업교육인 교사 20명을 대상으로 1차 델파이 설문지와 동일한 설문지를 바탕으로 설문을 진행하였다. 델파이 조사 대상으로 모집단으로서 학교현장에서 직업교육을 담당하고 교육경험을 바탕으로 본 연구에 다양한 의견제공이 가능한 실제적인 전문가 집단인 166개교의 특수학교에서 직업을 담당하는 직업교육 및 전공과담당 교사, 전국 24개교의 학교기업담당 교사, 39개교의 직업교육 거점학교에서 근무하는 교사들을 모집단으로 선정하였다. 특수학교의 경우 142부, 학교기업 24부, 통합형 직업 거점 학교 39부를 배포하였다. 1차 122부, 2차 64부를 회수하여 본 연구에 활용하였다. 첫째, 성과관련 지표 분석을 위한 탐색적 요인 분석을 통하여 지적장애인 중등 이후 교육 평가 프로그램에서 요인Ⅰ는 프로그램계획, 요인Ⅱ는 직원채용, 요인Ⅲ은 행정, 요인Ⅳ은 학생 계획, 요인Ⅴ은 학생활동, 요인Ⅵ은 자기결정, 요인Ⅶ은 기관 간 협력, 요인Ⅷ은 감독, 요인Ⅸ는 평가로 명명하였고 지적장애인의 중등 이후 교육 프로그램 평가도구 영역으로서 상기의 9가지 요인으로 추출하였다. 상기의 9가지 요인 81개 문항을 바탕으로 1차, 2차 델파이 설문을 실시한 결과 81개 문항전체가 타당하며 중요한 지표라는 결과가 나왔으며 이에 따라 지적장애인의 중등이후 교육프로그램 평가도구를 제시하였다. 프로그램계획, 직원 채용, 행정, 학생계획, 학생 활동, 자기 결정, 기관 간 협력, 감독, 평가의 9개 영역에 따른 81개의 문항으로 구성된 이 평가 도구는 교육과 평가를 동시에 수행하면서 향후의 추수지도를 가능하게 구성되어 있는 도구이며 이러한 9가지 영역은 장애학생들을 중등 이후 고육기관에서 지도하는 전문가들에 의해서 수행되거나 학부모, 학생, 본인에 의해서 수행 될 수 있다. The purpose of this study is to develop outcome-related indicator on post-secondary education evaluation program and then is to develop post-secondary education program evaluation tool for people with intellectual disabilities. For this purpose, the study took exploratory factor analysis and twice delphi method. For exploratory factor analysis, the Researcher carry out a survey targeting 20 special teachers who have vocational education teacher`s certificate for secondary eduction in Seoul and Gyeonggi-do. For delphi method, to collect professional and practical information, questionnaires were distributed to 166 special schools and 24 school based enterprise programs, 39 integrated vocational education core schools. Among them, the returned ones were 46 special schools and 20 school based enterprise programs, 36 core schools. Total 122 were collected. For second delphi, surveys were distributed to 122 first survey respondent and returned 64 surveys. the research results were based on these surveys. The conclusions of the study are as follows; First, exploratory factor analysis for outcome-related indicator on post-secondary education evaluation program draw following conclusion. post-secondary education program evaluation tool have 9 values. ValueⅠ is Program Planning, ValueⅡ is Staffing, ValueⅢ is Administration, ValueⅣ is Student Planing, ValueⅤ is Student Activities, ValueⅥ is Self Determination, ValueⅦ is Interagency Collaboration, ValueⅧ is Monitoring, ValueⅨ is Evaluation. Based on these 9 Values and it’s 81 questions, twice the delphi survey were made and distributed to study targets. And result of twice delphi survey are all these 9 values and it’s 81 question have validity. So, this study propose post-secondary education program evaluation tool for people with intellectual disabilities that composed of 9 values and it’s 81 questions. Based on the research finding, further proposals can be suggested. In Korea, there are lack of post-secondary education program evaluation tool for people with intellectual disabilities and other disabilities. So, with this tool, it is possible to assess post-secondary education program for people with intellectual disabilities. And this can the program better and strengthen the weak point. And then the program can provide practical and realistic service to people with intellectual disabilities. Finally, this study have a limit because research respondent were only special teachers who are not real post-secondary education service provider. And also, other rehabilitation professional were not participate this surveys. So more research should be conducted to gather the opinions of the hands-on workers and to standardize this tool.

위너필터를 이용한 ATSC 신호 감지

최우형(Woo-Hyoung Choi),이승준(Seung Joon Lee) 한국정보기술학회 2013 한국정보기술학회논문지 Vol.11 No.4

In this paper, the possibility and the performance gain of using a Wiener filter for ATSC signal sensing are studied. It is investigated whether the characteristics of the ATSC signal satisfy the requirements necessary for applicability of the Wiener filtering to it. Winer filtering improves the signal sensing performance in that it can reduce the noise effect. The performance of the sensing scheme with Wiener filtering is compared to that of the energy detector for the real signal of the ATSC capture files as well as an ideal ATSC signal. Even when applied to real ATSC capture file signals, a covariance matrix required in Wiener filtering is obtained, for practicability, by using the ideal ATSC signal. It is confirmed from computer simulations that the Wiener filtering-based signal sensing scheme has performance gains of 1.0~1.5 dB over the energy detector.

자기상관 함수와 FFT를 이용한 FM 무선마이크 신호 감지

최우형(Woo-Hyoung Choi),이승준(Seung Joon Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.11

It is difficult to sense primary users’ FM wireless microphone signal in the TV white space, since it is unavailable in advance where the microphone signal of 200kHz bandwidth is located within the TV white space of much wider bandwidth of 6MHz. Motivated by the fact that the received FM wireless microphone signal is independent of white noise and the white noise has zero autocorrelation at non-zero time differences, a novel sensing method for detecting such FM wireless microphone signal is proposed in this paper, which employs autocorrelation function and FFT operation. When the proposed scheme is compared with the best known conventional method in terms of the SNR for obtaining 90% detection probability, the former is shown to have performance SNR gains of 0.7dB, 1.5dB, and 1dB than the latter for the three microphone signal models of Silent, Soft Speaker, and Loud Speaker models, respectively. In addition, the proposed algorithm is found to have the same performance in a fading channel as in the line-of-sight channel.

주파수 영역에서 상관계수와 왜도를 이용한 스펙트럼 감지

최우형(Woo-Hyoung Choi),이승준(Seung Joon Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.9

Due to ever-increasing wireless communication services, limited resources of radio frequency band are being exhausted. For solving this problem, cognitive radio technologies are actively under study, where an empty frequency band not occupied by a primary user is borrowed by a secondary user. IEEE 802.22WRAN is working that standardization of spectrum sensing in TV White Space. However The conditions proposed by the IEEE802.22WRAN is difficult task because it requires low SNR when spectrum sensing. In this paper, a new spectrum sensing scheme using a correlation coefficient and skewness is proposed. The superiority of the scheme is justified by verifying that it satisfies the required performance suggested by IEEE802.22WRAN and it also outperforms the conventional scheme known as the spectrum sensing.

불명료한 출혈로 발현된 공장의 이소성 췌장

최우형 ( Woo Hyung Choi ),장형진 ( Hyoung Jin Chang ),승지환 ( Jee Hwan Seung ),고봉석 ( Bong Suk Ko ),강상범 ( Sang Bum Kang ) 대한소화기학회 2013 대한소화기학회지 Vol.62 No.3

A jejunal ectopic pancreas, where pancreatic tissue is found outside of the usual anatomical location, is a rare submucosal tumor that may cause obscure gastrointestinal (GI) bleeding. After initial negative endoscopic evaluation of the obscure GI bleeding, including colonoscopy and/or upper endoscopy, it is reasonable to proceed with further evaluation of the small bowel. Diagnostic options for the evaluation of the small bowel may include capsule endoscopy, push enteroscopy, or barium contrast small bowel studies. Here, we report a case of obscure GI bleeding caused by a jejunal ectopic pancreas, diagnosed through capsule endoscopy and barium contrast small bowel studies, which was treated successfully with single incision access laparoscopy. (Korean J Gastroenterol 2013;62:165-168)

레일리 페이딩 채널에서 새로운 협력 스펙트럼 검출 방식

진광훈(Kwang-Hun Jin),최우형(Woo-Hyoung Choi),이승준(Seung Joon Lee) 한국정보기술학회 2014 한국정보기술학회논문지 Vol.12 No.10

Individual spectrum sensing by each secondary user for detecting the existence of the primary user in cognitive radio may lead to the problem of a hidden terminal, causing performance degradation. Cooperative spectrum sensing has been considered to address this problem. In this paper, a novel combining scheme for cooperative spectrum sensing is proposed. The proposed scheme originates from the Chair-Carshney (CV) scheme. However, the proposed scheme does not use hard-decision values of the local detection signals received by the secondary users. Instead it uses the local detection signals from the secondary users as they are. Also the proposed scheme employs weighting factors different from those used in the CV scheme for combining signals received from the secondary users. Although the proposed scheme requires the same amount of information as the CV scheme, it is shown in computer simulation results that the former has superior detection performance to the latter.