• 한국시스템다이내믹스연구
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• 제3권1호
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• pp.61-77
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• 2002

This paper reviews issues and methodological status of system dynamics and suggest some research agenda for its development in Korea. After reviewing some characteristics of system dynamics approach, including dynamic feedback perspective and endogenous point of view, the paper pointed out methodological characteristics of system dynamics. It seems to be the most notable characteristics of System Dynamics that it use both quantitative and qualitative approach in explaining and modelling reality. Besides, System Dynamicists rely more heavily on refutationism than instrumentalism and this allows System Dynamicists follow more strict way of scientific inquiry. For the development of System Dynamics in Korean academic circle, developing training program and curriculum, networking scattered System Dynamicist all over the country, would be the most important task.

• 기술혁신학회지
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• 제5권3호
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• pp.307-320
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• 2002

The purpose of this paper was to design evaluation process on technological information analysis done by re-tired scientists and engineers. Existing studies on evaluation system and methodology were analyzed and their implications are as follows. To provide useful feedback to the retired scientists, indicators of evaluation should be simplified and method of evaluation confined to the quantitative one. And the results of evaluation need to be utilized in direction to encourage the old scientists and engineers.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.259-264
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• 1997

본 논문에서는 Westinghouse(WH)사에서 공급한 고리 3, 4호기의 증기발생기 모델에 강인제어 기법의 하나인 QFT(Quantitative Feedback Theory)를 적용하여 플랜트에 존재하는 불확실성이나 외란에 대해 강인성을 보장하는 제어기를 설계하였다. 증기발생기의 주파수응답 한계조건은 MATLAB QFT Toolbox를 이용하였으며, loop shaping에 의한 전달함수 식별을 위해서 근사화 기법을 적용하였다. 그리고 5∼20[%]의 저출력구간에서 모의실험을 하여 본 논문의 유용성을 보였다.

• 한국융합학회논문지
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• 제8권10호
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• pp.249-255
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• 2017

국내 관광업계는 대부분의 고객 만족도를 정량적인 설문조사에 의존한다. 하지만 고객의 설문 참여도가 지극히 저조하고, 불만족 요인에 대한 개선이 신속히 이루어지고 있지 못하고 있는 것이 사실이다. 본 연구에서는 고객 피드백 정보의 정확성과 분석 과정의 효율성을 높이기 위해 새로운 토픽맵 시스템을 제안하고, 그 실증적 효과성을 입증한다. 토픽맵 시스템은 기존의 설문시스템에서 획득한 일정기간의 정량자료와 실시간 SNS를 통해 수집된 정성적 자료를 텍스트 마이닝 및 온톨로지 기법을 활용하여 대량의 고객 피드백 자료를 분석하는 시스템으로써, 분석된 불만요인에 대하여 토픽맵 시스템으로 실시간 개선점을 제공하고 그 이후의 효과 또한 실시간으로 모니터링할 수 있는 고객만족도 평가 방식 시스템이라 할 수 있다. 이로써 개선요소의 정교한 우선순위를 제공하고, PDCA 환류시스템으로서의 품질관리가 가능해진다. 또한 조사기간 및 비용이 대폭 단축되고, 기존 방식에 비해 훨씬 정확한 대응이 가능하게 되어 진다. 실제 적용사례로써 국내 최대 규모의 H여행사에 적용하여 제안 시스템의 정확성과 효율성을 입증한다.

• The Journal of Korean Physical Therapy
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• 제14권1호
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• pp.75-88
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• 2002

The purpose of this study was to investigate the influence of anterior, posterior, and lateral pelvic tilt exercise upon the gait characteristics of patients with hemiplegia including their gait velocity, cadence, stride length, step length of the non affected side, step length of the affected side, foot angle of the non affected side, foot angle of the affected side, base of support, and so on. The subject of this study was 24 men and women patients with hemiplegia. The patients, the subject of this study, were classified into 12 patients of treatment group applying pelvic tilt exercise using visual feedback and 12 patients of control group applying general pelvic tilt exercise, and then analyzed their gait before and after exercise. Temporal distance gait analysis (Boening, 1977) was used to analyze their gait, and ink foot-print was applied as on of measurement methods. To find out meaningful difference between control group and treatment group, this study carried out independent sample t-test for each item by utilizing SPSS/Win 10.0, compared changes in control group's and treatment group's gait characteristics before and after exercise as percentage, and applied paired t-test to conduct before-after test in same group. Statistical significance level was ${\alpha}$ < 0.05. The results of this study were as follows. As a result of independent sample t-test for control group's and treatment group's gait characteristics after exercise, it was not statistically significant so there was no meaningful difference between two groups. However, it was statistically significant in the change rate(%) of gait characteristics, and treatment group's patients with hemiplegia had been highly changed in gait characteristics in comparison with control group. From the above-mentioned results, could find that pelvic tilt exercise using visual feedback for patients with hemiplegia was effective to improve their gait ability and it could increase the ability in comparison with general pelvic tilt exercise. In the future, studies on the effect of pelvic tilt exercise using visual feedback shall be continued based on more quantitative methods.

• 한국정밀공학회지
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• 제26권2호
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• pp.45-53
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• 2009

Today, reduction of $CO_2$ exhaustion gas for global-warming prevention becomes important issues in all industrial fields. Hydraulic systems have been widely used in industrial applications due to high power density and so on. However hydraulic pump is always being operated by engine or electric motor in the conventional hydraulic system. Therefore most of the conventional hydraulic system is not efficient system. Recently, an electro-hydraulic hybrid system, which combines electric and hydraulic technology in a compact unit, can be adapted to a wide variety of force, speed and torque requirements. In the electro-hydraulic hybrid system, hydraulic pump is operated by electric motor only when hydraulic power is needed. Therefore the electro-hydraulic system can reduce the energy consumption drastically when compared to the conventional hydraulic systems. This paper presents a new kind of hydraulic load simulator which is composed of electro-hydraulic hybrid system. Disturbances in the real working condition make the control performance decrease or go bad. QFT controller is designed to eliminate or reduce the disturbance and improve the control performance of the electro-hydraulic load simulator. Experimental results show that the proposed controller is verified to apply for electro-hydraulic hybrid system with varied external disturbances.

• Safety and Health at Work
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• 제7권3호
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• pp.194-200
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• 2016

Background: The influence of sociocultural factors on human reliability within an open sociotechnical systems is highlighted. The design of such systems is enhanced by experience feedback. Methods: The study was focused on a survey related to the observation of working cases, and by processing of incident/accident statistics and semistructured interviews in the qualitative part. In order to consolidate the study approach, we considered a schedule for the purpose of standard statistical measurements. We tried to be unbiased by supporting an exhaustive list of all worker categories including age, sex, educational level, prescribed task, accountability level, etc. The survey was reinforced by a schedule distributed to 300 workers belonging to two oil companies. This schedule comprises 30 items related to six main factors that influence human reliability. Results: Qualitative observations and schedule data processing had shown that the sociocultural factors can negatively and positively influence operator behaviors. Conclusion: The explored sociocultural factors influence the human reliability both in qualitative and quantitative manners. The proposed model shows how reliability can be enhanced by some measures such as experience feedback based on, for example, safety improvements, training, and information. With that is added the continuous systems improvements to improve sociocultural reality and to reduce negative behaviors.

• Journal of Construction Engineering and Project Management
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• 제5권2호
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• pp.24-34
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• 2015

The complexity arises in defining the construction quality due to its perception, based on inherent market conditions and their requirements, the diversified stakeholders itself and their desired output. A quantitative survey based approach was adopted in this constructive study. A questionnaire based survey was conducted, for the assessment of construction quality perception and expectations in the context of quality improvement technique. The survey feedback of professionals, from the leading construction organizations/companies of Pakistan were analyzed. The financial capacity, organizational structure, and construction experience of the construction firms formed basis for their selection. After statistical analysis of survey feedback it was found reliable and valid for the inferential purpose to the target population of construction professionals. The quality perception was found to be project scope oriented, considered as an excess cost for a construction project and keeping the rework minimum by qualifying the required quality tests, keeping the defects minimum by ensuring the specifications of supplied material. Any quality improvement technique was expected to address the financial aspects of the construction project for the employer and contractor, by increasing the profitability through reduction in overall cost, reduction in time, reduction in defects and improving the productivity in a construction project. The study is beneficial for the construction professionals to assess the prevailing construction quality perception and the expectations from implementation of any quality improvement technique in construction projects.

• 한국컴퓨터그래픽스학회논문지
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• 제13권2호
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• pp.23-29
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• 2007

본 논문은 증강현실 기반 제품 디자인환경에서 전자 제품의 프로토타이핑 (prototyping)을 제작을 위한 저작 도구를 제안한다. 이 저작도구는 하드웨어에 관한 전문적인 지식이 없는 일반 저작자를 위한 것이다. 제안된 저작도구는 시/청/촉각 피드백 각각에 대한 저작을 동일 플랫폼에서 할 수 있는 환경을 제공하여 실질적인 제품 디자인이 가능하게 한다. 뿐만 아니라 모듈 각각에 대한 추상화된 속성 명시파일을 통해 사용자 인터페이스 재구성이 가능하여 특정 플랫폼에 독립적 구조가 가능하고 잦은 하드웨어 변경에 유연하게 대처할 수 있도록 한다. 마지막으로 제안된 사용자 인터페이스는 GUI 및 TUI 기반 저작 방법의 장점을 취합하여 GUI를 이용한 정밀한 조작과 TUI를 이용한 직관적인 저작이 가능하도록 한다. 제안된 저작 방법들은 전자 제품 프로토타이핑 저작뿐만 아니라 다감각 피드백을 사용할 수 있는 전시, 에듀테인먼트 콘텐츠와 같은 증강현실 응용프로그램의 저작의 경우에도 응용될 수 있다. 향후 연구로써 제안된 저작도구의 정량/정성적인 사용성 평가가 수행되어야 한다.

• 한국지능시스템학회논문지
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• 제13권6호
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• pp.698-703
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• 2003

본 논문에서는 카오스 신호를 이용하여 음성신호의 보안전송을 위한 아날로그 비화통신 시스템을 제안하고 통신성능을 분석하였다. 기존의 카오스 동기화 및 카오스 변조통신 알고리즘을 개선하여 통신환경에서 발생하는 다양한 조건들을 적용하여 음성신호의 복원능력을 모의실험 하였다. 일반적인 PC(Pecora ＆ Carroll) 제어기법과 제안한 SFB(Self-FeedBack) 마스킹 기법을 사용하여 송신단에서 음성신호를 카오스 신호로 마스킹하여 변조하고, 통신채널에 잡음신호를 추가하여 전송하였다. 수신단에서는 카오스 응답시스템을 이용하여 음성신호를 복조하고, 복원성능을 계산하기 위하여 아날로그 복원 에러 신호의 평균전력을 제안하여 계산하였다. 실험결과 마스킹 정도, 파라미터들의 민감성, 채널잡음 등에 대하여 PC 제어기법보다 피드백 제어기법의 복원성능이 우수함을 정량적인 데이터로 확인할 수 있었다. 또한 로렌쯔 카오스 비화통신시스템에 사용할 경우 파라미터들의 조합으로 암호키를 구성해야 하므로 파라미터 변화율에 대응하는 복원에러율의 관계를 모의실험 값으로 구하였다.