• 인터넷정보학회논문지
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• 제3권1호
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• pp.81-90
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• 2002

대다수의 인터넷 기반의 분산 어플리케이션이나 클라이언트/서버의 응용은 부하균등, 통신 지연, 네트워크 결함 등의 문제점을 처리하여 사용자에게 서비스해야 한다. 또한 화상 회의, VOD, 병행 소프트웨어 공학과 같은 정교한 응용프로그램들은 추상적인 그룹 통신을 필요로 한다. 이러한 페러다임들을 현재의 CORBA 버전들은 적절히 수용하지 못한다. CORBA는 주로 Point-to-Point통신을 하기 때문에 분산 시스템에서 예측 행위를 하는 신뢰성 있는 응용 기술에 대한 구현은 지원하지 않는다. 따라서, 본 논문에는 분산 컴퓨팅 환경 하에서 CORBA-ORB를 이용한 그룹 통신, JAVA-RMI를 이용한 그룹 통신, 소켓을 이용한 그룹 통신 등을 설계 및 구현을 하였으며, 이에 따른 성능 분석을 실시하였다. 성능 분석은 객체의 증가에 따른 지연시간으로 측정하였고 CORBA의 ORB를 이용한 그룹 통신의 경우 평균은 14.5172msec, JAVA의 RMI를 이용한 그룹 통신의 경우 평균은 21.4085msec, 소켓을 이용한 그룹 통신의 경우 평균은 18,0714msec가 나왔다. 멀티캐스트와 UDP를 이용한 그룹 통신은 각각 0.2735msec, 0.2157msec로 측정되었음을 알 수 있다. 논문의 결과로 객체의 증가에 따라 CORBA-ORB 그룹 통신의 성능향상을 보였다. 본 연구는 결함 허용 클라이언트/서버 시스템. 그룹웨어, 텍스트 검색엔진. 금융 정보 시스템 등에 적용 가능하다.

• 한국컴퓨터정보학회논문지
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• 제25권4호
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• pp.165-172
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• 2020

본 연구에서는 현재 일반적인 스마트 팩토리에서 데이터 전송에 사용하는 중앙 집중형 시스템에서 발생하는 데이터를 중앙의 센터까지 전송, 처리할 때 발셍하는 전송 지연 등의 문제 해결을 위하여 필요한 곳에 연산과 저장 장치를 도입하는 분산 컴퓨팅 패러다임 (Distributed Computing Paradigm)인 온-디바이스 (On-Device) 기반 에지 컴퓨팅 (Edge Computing) 기술과 빅데이터 분석 기술 및 활용 방법의 연구를 통하여 설비 고장 등을 예지하여 가동율을 높일 수 있는 산업현장의 설비관리에 활용되는 솔루션을 제안한다. 그러나 에지 컴퓨팅 기반의 기술이 실제 적용되더라도 네트워크 에지에서 장치의 증가는 많은 양의 데이터가 데이터 센터로 전달되어 네트워크 대역이 한계치에 이르게 되어 네트워크 기술의 향상에도 데이터 센터는 수많은 응용에서 중요한 요건이 되는 수용 가능한 전송 속도와 응답 시간을 보장하지 못하게 된다. 이와 같은 요구조건을 수용할 수 있는 일체형 하드웨어 기술과 공장관리 및 제어 기술을 적용한 설비보존 및 스마트 팩토리 산업 분야에 적용할 수 있는 연구를 통하여 생산성 증대를 지원할 수 있는 지능적 설비관리를 지원하도록 하여 추후 빅데이터에 적합한 딥러닝을 적용할 수 있는 인공지능 기반 설비 예지 보전 분석 도구로 발전할 수 있는 기반을 제공한다.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2004년도 International Conference on Digital Policy & Management
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• pp.39-53
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• 2004

Data production systems are generally very large, distributed and complex systems used for creating advanced (mainly statistical) reports. Typically, data is gathered periodically and then subsequently aggregated and separated during numerous production steps. These production steps are arranged in a specific sequence (workflow or production chain), and can be located worldwide. Today, a need for improving and automating methods of supervision for data production systems has been recognized. Supervision in this context entails planning, monitoring and controlling data production. Two significant approaches are introduced here for improving this supervision. The first is a 'closely-coupledd' approach (meaning direct communication between production jobs and supervisory tool, informing the supervisory tod immediately about delays in production) - based upon traditional production planning methods typically used for manufacturing (goods) and adopted for working with data production. The second is a 'loosely-coupled' approach (meaning no direct communication between supervisory tool and production jobs is used) - having its origins in proven traditional project management. The supervisory tool just enquires continuously the progress of production. In both cases, dates, costs, resources, and system health information is made available to management. production operators and administrators to support a timely and smooth production of periodic data. Both approaches are theoretically described and compared. The main finding is that, both are useful, but in different cases. The main advantages of the closely coupled approach are the large production optimisation potential and a production overview in form of a job execution plan, whereas the loosely coupled method mainly supports unhindered job execution and offers a sophisticated production overview in form of a milestone schedule. Ideas for further research include investigation of other potential approaches and theoretical and practical comparison.

• 인터넷정보학회논문지
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• 제9권3호
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• pp.51-58
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• 2008

무선 센서네트워크는 효율적인 자료처리 및 유비쿼터스 시스템 구현을 위해 여러 응용에서 사용되고 있다. 그러나 무선센서네트워크에 기반 한 최근 주차관리시스템 연구에서는 적응형 센싱이나 효율적인 자료처리 기법은 거의 고려되지 않고 있다. 주차관리응용에서의 성능은 이러한 분산된 컴퓨팅장비들의 효율적인 구현에 영향을 받는다. 이 논문은 주차관리 유비쿼터스 네트워크 시스템을 위해 퍼지 무선센서를 이용한 적응형 센싱기법을 제시한다. 효율적인 주차탐색을 위해 퍼지추론시스템이 센서에 탑재된다. 또한 자동차 주차공간의 환경변화에 적응을 위해 새로운 갈을 각 센서에 무선으로 전송하는 규칙기반 적응형 모듈을 제시한다. 실험결과 제안한 퍼지기반 무선센서가 일반적인 무선센서에 의해 수집하는 방법에 비해 우수한 처리율과 적은 지연시간을 보였다.

• 대한기계학회논문집
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• 제11권1호
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• pp.118-123
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• 1987

본 연구에서는 새로 고안된 연료주입기(air injector)바로 뒤에 입사압축파를 반사시키기 위한 벽을 설치하므로써 고체입자의 입사압축파에 대한 노출을 최대한 줄 였고 또한 새로운 연료주입기에 의해 매우 잘 분포된 입자분포를 얻을 수 있었다. 반사압축파에 의해 생성된 고온 고압의 산소중에서의 고체입자의 점화지연시간을 측정 하므로써 기체유동이 존재하는 입사압축파실험에서의 점화지연시간과 비교하여 기체유 동이 고체 미립자의 점화에 미치는 영향을 알아볼 수 있었고 반사압축파에 의한 점화 상태 조건하에서도 표면 점화모델이 성립하는지를 고찰해 보았다.

• 정보처리학회논문지A
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• 제14A권7호
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• pp.451-456
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• 2007

이 논문에서는 컴퓨터 시스템을 이질적 서버들로 구성된 시스템으로 간주하고, 장기적 관점에서 응용들간의 공정성을 추구하는 누적적(累積的) 공정 스케줄링 방법을 제시한다. 기존의 단일 서버 환경에서 주로 사용되는 GPS(generalized processor sharing) 기반의 스케줄링 알고리즘들은 순간적 관점에서 서버의 용량을 분배한다. 그러나 이를 이질적 다중 서버 환경에 적용하는 경우, 스케줄링 순서에 의한 지연시간의 오차가 서버들을 거치면서 누적될 수 있고, 잉여용량이 순간적 관점에서만 배분되기 때문에 장기적 관점에서 불공정성 문제가 발생할 수 있다. 본 논문의 방법에서는 각 응용의 예약용량을 보장하면서 잉여용량의 적절한 배분을 통해 장기적 관점의 공정 서비스를 추구한다. 이를 위해, 각 응용이 이상적으로 진행되기 위해 받아야 할 공정한 서비스 용량을 주기적 관찰을 통해 동적으로 파악하여 참조용량 모델로 삼고, 스케줄러는 응용들이 이 참조용량 모델을 점진적으로 따르도록 한다. 또한 이 모델을 효율적으로 구현하기 위한 휴리스틱 알고리즘을 만들고 실험을 통해 이를 검토한다.

• 한국의료질향상학회지
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• 제19권2호
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• pp.80-88
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• 2013

Objectives: With the increase in the number of people who are marginalized in receiving medical services, the role of Seoul National University Hospital as a public hospital is being emphasized. However, many patients are either experiencing delays in receiving medical services or simply being left out as a result of the inaccessibility to the department of social work on part of both the patients and the medical staff. Methods: In order to increase consultation from other departments and the accessibility to the department of social work for the socially marginalized group through early consultation from other departments, the following steps were taken. First, an orientation program for novice medical residents led by clinical social worker was introduced/implemented. Second, posters and brochures on various financial aids programs were produced and distributed. Third, a system of early screening was built/constructed, and once a week rounds and early screening meeting were executed/carried out. Result: The department of social work's rate of consultation from other departments increased by 4.4% compared to last year, while it showed 61% increase for those wards that had an early screening meeting. In addition, the average time of consultation from other departments was reduced by 3.1 days, securing sufficient amount of time for clinical social work services, both in terms of quality and quantity. Conclusion: It is believed that the various promotional activities, along with the strengthening of accessibility to clinical social work services and early consultation on part of social disadvantaged/marginalized group, would undoubtedly help provide quality services to patients and increase their level of satisfaction. In this way, the wards can effectively reduce the number of unnecessary hospital stay days while the hospital can prevent the accumulation of outstanding bills/fees as well as contribute to the publicness of hospitals. The promotion of clinical social work programs in various ways are crucial to ensuring the satisfaction of patients and hospital staff.

• 부모자녀건강학회지
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• 제5권2호
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• pp.177-190
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• 2002

This study were conducted to assess the physical growth and developmental status of infants in orphanage in order to provide an empirical data. The subjects for this study were 104 infants and toddlers who were reared in an orphanage in D Metropolitan city. The instrument used for this study were anthropometric assessment and DDST for normative data of development. Data has been collected from September 1st, 1998 to August 31st, 2000 and were analyzed using SPSS/PC(Version 10.0) with frequency, mean, standard deviation, ANOVA and Chi-square test. The results of this study were as follows; 1. 30.8% of infants in orphanage had abnormal weight, 26.9% had abnormal length, and 22.1% had abnormal head circumference and most of them were distributed below 50 percentile of growth chart. 2. 53.8% of infants in orphanage had normal, 27.9% had qustionable, and 18.3% had abnormal developmental screening test results, especially, 31.5% of infants in orphanage ages 3 to 5 years had abnormal developmental screening test results, according to the Denver Developmental Screening Test(DDST). There was a significant developmental delay noted in the language and fine motor-adaptive sector. 3. It is anticipated that developmental delays would increase in severity by older the mean age of orphanage infants and longer the time being raised in orphanage. It would be concluded that the physical growth and developmental status of orphaned infants were very vulnerable and serious and it is suggested that there needed an effective intervention strategies to promote growth and development of infants in orphanage.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.201-205
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• 1997

With the recent advance of Web and its associated technologies, information sharing on distribute computing environments has gained a great amount of attention from many researchers in many application areas, such as medicine, engineering, and business. One basic requirement of distributed medical consultation systems is that geographically dispersed, disparate participants are allowed to exchange information readily with each other. Such software also needs to be supported on a broad range of computer platforms to increase the software's accessibility. In this paper, the development of world-wide-web based medical consultation system or radiology imaging is addressed to provide the platform independence and great accessibility. The system supports sharing of 3-dimensional objects. We use VRML (Virtual Reality Modeling Language), which is the de-facto standard in 3-D modeling on the Web. 3-D objects are reconstructed from CT or MRI volume data using a VRML format, which can be viewed and manipulated easily in Web-browsers with a VRML plug-in. A Marching cubes method is used in the transformation of scanned volume data set to polygonal surfaces of VRML. A decimation algorithm is adopted to reduce the number of meshes in the resulting VRML file. 3-D volume data are often very large-sized, and hence loading the data on PC level computers requires a significant reduction of the size of the data, while minimizing the loss of the original shape information. This is also important to decrease network delays. A prototype system has been implemented (http://netopia.snu.ac.kr/-cyber/). and several sessions of experiments are carried out.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.236-246
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• 2003

This paper is implemented a control algorithm in order to be stable and minimized to entire train traffic system at delayed case. Signal ing system is described wi th algebraic equations given for train headway, Discrete-event simulation principles are reviewed and a demonstration block signaling model using the technique is implemented. Train congestion at station entrance for short headway operation is demonstrated and the propagation of delays along a platform of trains from any imposed delay to the leading train is also shown. A rail way signaling system is by nature a distributed operation with event triggered at discrete intervals. Although the train kinematic variables of position, velocity, and acceleration are continually changing, the changes are triggered when the trains pass over section boundaries and arrive at signals and route switches. This paper deals with linear-mode1ing, stability and optimal control for the traffic on such metro line of the model is reconstructed in order to adapt the circuits. This paper propose optimal control laws wi th state feedback ensuring the stability of the modeled system for circuits. Simulation results show the benefit to be expected from an efficient traffic control. The main results are summarized as follows: 1. In this paper we develop a linear model describing the traffic for both loop lines, two state space equations have been analyzed. The first one is adapted to the situation where a complete nominal time schedule is available while second one is adapted when only the nominal time interval between trains is known, in both cases we show the unstability of the traffic when the proceeding train is delayed following properties, - They are easily implemented at law cost on existing lines. - They ensure the exponetial stability of loop system. 2. These control laws have been tested on a traffic simulation software taking into the non-linearites and the physical constraints on a metro line. By means of simulation, the efficiency of the proposed optimal control laws are shown.