원격탐사를 위한 병렬계산 기법

김형중,장태정,김희원,김형수,이정문,장순자 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-

원격탐사에 사용되는 편미분방정식을 고속으로 풀기 위한 기법을 프로그래밍하고 성능을 향상시킬 수 있는 방법을 제시했다. 미지수가 30만개 이상되는 복소수(non-Hermitian) 행렬의 해를 구하는 프로그램을 작성했다. 이 프로그램은 C와 PVM에 기반을 두고 있다. 수렴속도를 향상시키기 위해 대각 스케일링을 이용했다. 통신속도의 개선을 위해 데이터 압축 기법을 이용했다. 수렴속도를 측정 제시함으로써 실제 문제 적용에 참고할 수 있다. Network-based computing with cluster of personal computers or workstations recently has become an important and successful technique. Network-based computing enables fast computation and resolves short of storage with computers on the desks. Cluster of inexpensive computers offers them aggregated computing power and storage to challenge very large-scale problems. Iterative solvers are used for the large sparse linear systems. Preconditioners accelerate the rate of convergence of the iterative solvers. However, parallelization accelerate the rate of convergence of the iterative solvers. However, parallelization of preconditioners is far from satisfaction so far. Thus, the simplest diagonal scaling is a good alternative for improved convergence and easy parallelization. In order to reduce communication overhead, a data compression technique is considered. Data communication time can be reduced at the cost of convergence rate. MATLAB simulation result is given in this paper. This method is effective to cluster of computers connected through slow networks.

전기ㆍ전자 신뢰성 시험을 위한 전문가 시스템

송경철,장중순,김명수 대한설비관리학회 2001 대한설비관리학회지 Vol.6 No.1

An expert system is developed to help reliability engineers to set up testing plans. The testing procedures for electric and electronic components in IEC standards and military standards are included in a database and the system can display appropriate testing procedures for the failure modes and causes which will be specified by users.

生産工程의 最適工程平均의 決定

李敏九,張重淳,金明洙 西原大學校 經營科學硏究所 1997 經營硏究 Vol.6 No.1

관상동맥질환자에서 경흉부 도플러 심초음파를 이용한 좌심실 확장기 기능의 평가 : 좌심실 확장기 장애 형태에 따른 분류

전희경,윤호중,유기동,박지원,전두수,정욱성,채장성,김재형,최규보,홍순조 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.1

심인성 색전 요인이 없는 뇌경색 환자에서 경식도 심초음파와 Acoustic Quantification을 이용한 대동맥 탄성의 평가

이종민,윤호중,임효영,박지원,김휘열,전희경,문건웅,정욱성,채장성,김재형,최규보,홍순조 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

하계 실내 및 실외환경의 공기 중 휘발성 유기화합물 농도 및 개인노출

양원호,손부순,박종안,장봉기,박완모,김윤신,어수미,윤중섭,류인철 한국환경과학회 2003 한국환경과학회지 Vol.12 No.9

Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene. Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).

관상동맥 풍선성형술 후 발생한 관상동맥 박리의 초기 조영술적 고찰

고영엽,강지인,장재혁,강민정,정중화,장경식,홍순표 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.1

Background and Objectives: Percutaneous coronary intervention (PCI) is widely utilized in the treatment of symptomatic coronary artery disease (CAD). Althouth it has numerous benefits, intimal tear or dissection, serious and potentially life-threatening complications of plain old balloon angioplasty (POBA) can occur. The aim of this study was to assess the implications of coronary dissections after ballon angioplasty. Methods: 78 consecutive patients (age, 62 +/- 11 years; 46 men, 32 women) identified to two groups as having with or without dissection (dissection (D) group or non-dissection (ND) grouP) underwent balloon angioplsty for CAD were studied. All patients with dissection could be managed by successful stent implantation to rescue the artery. The morbidity of ischemic complication and mortality were evaluated for 30days after PCI. Results: Coronary dissection developed 44 lesions (38%) in 31 patients out of 117 lesions in 78 patients after POBA and a good final angiographic result was obtained in all patients with dissection, Significant correlates of a development of dissection were the lesion morphology of ACC/AHA type B and C (P<0.05). There were no significant correlations of clinical pictures, whether POBA in single vessel disease or in multivessel disease, diameter stenosis before POBA, and balloon/coronary artery diameter ratio. Morphologic feature of dissection was type A in 15 (34%), type B in 13(30%), type C in 12 (27%), and type D in 4 (9%). After PCI, there was no ischemic complication or death related coronary dissection during follow-up period for 30days. Conclusions: Coronary dissection after angioplasty occurred in 44 lesions (38%) out of 117 lesions of 78 consecutive patients underwent POBA. Coronary dissection after POBA significantly correlated with the severity of lesion morphology. Coronary stenting is effective in the management of acute coronary dissections after angioplasty.

초음파 펄스에코 신호의 3차원 처리

송문호,손상락,조정호,성제중,안형근,장순재 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.5

비파괴 시험을 위한 3차원 구조의 초음파 영상에는 다양한 결함을 명백하게 보여줄 수 있을 만큼 상세하고 쉽게 알아볼 수 있는 정보가 제공되어야 한다. 수년 동안 원자력 발전소에서 사용된 금속관에 발견되는 소규모의 균열은 전형적인 결함들인데, 이러한 밀리미터 이하의 균열이나 결함은 최종 3차원 영상에서 묘사되어야만 의미있는 검사가 될 것이다. 향상된 선명도와 그에 따른 결함의 발견 과정의 한 단계로써, 펄스에코(pulse-echo) 초음파를 사용한 3차원 영상제작 기술을 제안한다. 이 기술은 필요한 스캐닝과 펄스에코 데이터의 처리과정을 통한 검사로 3차원 물체의 3차원 영상을 생성하는데, 2차원 위너필터(Wiener filter)에 의해 초음파 빔을 선명하게 하는 기술을 포함한다. 제안하는 위너필터는 빔의 전달에서 펄스에코 데이터를 초음파 빔 방향의 수직방향에 따라 필터링한다. 이 3차윈 처리과정은 결함의 선명성을 증진시키고 사용자에게 3차윈 구조물의 좌우 회전 및 축 회전과 같은 조작 능력을 제공한다. 이러한 조작 능력은 3차원에서 다양한 결함들의 크기와 위치의 분명한 묘사를 가능하게 한다. Infrasonic imaging of 3-D structures for nondestructive evaluation must provide readily recognizable images with enough details to clearly show various flaws that may or may not be present. Typical flaws that need to be detected are miniature cracks, for instance, in metal pipes having aged over years of operation in nuclear power plants; and these sub-millimeter cracks or flaws must be depicted in the final 3-D image for a meaningful evaluation. As a step towards improving conspicuity and thus detection of flaws, we propose a pulse-echo ultrasonic imaging technique to generate various 3-D views of the 3-D object under evaluation through strategic scanning and processing of the pulse-echo data. We employ a 2-D Wiener filter that filters the pulse-echo data along the plane orthogonal to the beam propagation so that ultrasonic beams can be sharpened. This three-dimensional processing and display coupled with 3-D manipulation capabilities by which users are able to pan and rotate the 3-D structure improve conspicuity of flaws. Providing such manipulation operations allow a clear depiction of the size and the location of various flaws in 3-D.

Discrete Event Simulation-Based Reliability Evaluation of a Traffic Signal Controller

Jang, Joong Soon,Park, Sang C. Hindawi Limited 2018 Modelling and simulation in engineering Vol.2018 No.-

<P>A mission reliability evaluation methodology for a signal traffic controller is presented in this paper. To develop the new evaluation methodology, this paper combines the Discrete Event System Specification (DEVS) formalism which has been popular in manufacturing area for three reasons: (1) its features compatible with the object-oriented modeling; (2) its rigorous formal definition; and (3) its support for the specifications of discrete event models in a hierarchical and modular manner. By using the DEVS formalism, we construct a simulation model which takes into account not only the characteristics of a traffic signal controller but also the operating environment. Once a model is constructed, it is possible to perform simulation experiments. The proposed methodology computes the mission reliability of a traffic signal controller by using a simulation record, and this information plays a vital role in preparing optimized maintenance policies that maximize availability or minimize life cycle costs.</P>

Estimation of Parameters of a Two-State Markov Process by Interval Sampling

Jang, Joong Soon,Bai, Do Sun 한국경영과학회 1981 韓國經營科學會誌 Vol.6 No.2

This paper develops a method of modifying the usual maximum likelihood estimators of the parameters of a two state Markov process when the trajectory of the process can only be observed at regular epochs. The method utilizes the limiting behaviors of the process and the properties of state transition counts. An efficient adaptive strategy to be used together with the modified estimator is also proposed. The properties of the new estimators and the adaptive strategy are investigated using Monte Carlo simulation.