• 항공우주시스템공학회지
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• 제14권1호
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• pp.16-20
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• 2020

차량이 주행 중에 그리고 항공기가 활주로에 착륙하는 순간과 활주 중에 발생하는 피로는 착륙장치, 기체와 차량의 현가장치 등에 수명 주기와 밀접한 관련이 있다. 휠에 작용하는 하중들은 종축 힘, 횡력, 수직력과 제동력이다. 차량의 동특성과 내구성을 연구하기 위해 본 논문의 시뮬레이터는 시험실에서 실제 노면 형상을 재현에 사용된다. 그러므로 제품 개발 시간과 비용을 절감할 수 있다. 하드웨어적으로 유압 피로 시뮬레이터 구조의 중요한 요소는 각 축을 분리하고 여러 하중과 진동을 견뎌내는 것이다. 본 논문의 역기구학적 해석 방법은 Dummy wheel 중심에서 축 방향으로 최대 동작 변위를 준 후 커플링에 의한 유압 서보 작동기의 작동 크기를 도출한다. 해석의 결과는 실제 노면 형상을 정확하게 재현하기 위해 축 간의 커플링이 미약함을 확인하는 것이다.

• Smart Structures and Systems
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• 제14권3호
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• pp.327-345
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• 2014

This paper presents a composite control strategy for the active suppression of vibration due to the unknown disturbances, such as external excitation, harmonic effects and control spillover, as well as high-frequency accelerometer measurement noise in the all-clamped stiffened plate. The proposed composite control action based on the modal approach, consists of two contributions including feedback part and feedforward part. The feedback part is the well-known PID controller, which is widely used to increase the structure damping and improve its dynamic performance close to the resonance frequencies. In order to get better performance for vibration suppression, the weight matrixes is optimized by chaos sequence. Then an improved disturbance observer (IDOB) as the feedforward compensation part is developed to enhance the vibration suppression performance of PID under various disturbances and uncertainties. The proposed IDOB can simultaneously estimate the various disturbances dynamically as well as measurement noise acting on the system and suppress them by feedforward compensation design. A rigorous analysis is also given to show why the IDOB can effectively suppress the unknown disturbances and measurement noise. In order to verify the proposed composite control algorithm (IDOB-PID), the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened plate active vibration control system is set up. The experimental results demonstrate the effectiveness, practicality and strong anti-disturbances ability of the proposed control strategy.

• 한국임상약학회지
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• 제26권4호
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• pp.324-329
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• 2016

Background: With the development of information and communication technology, there is a growing number of people looking for health information on the internet. This pilot study was performed to analyze the pattern of pharmacist consultation on the internet portal site. Methods: Questions and answers posted on the portal site "Naver Jisik-iN" from March 1st to 31th in 2016 were collected. Medications asked were categorized into prescription drugs, nonprescription drugs, sanitary aids, emergency drugs, functional health foods, and others. Medications were subcategorized into 14 according to the anatomical therapeutic chemical classification system. Questions were divided into 10 categories based on Hepler's drug-related problems. Results: Of the 955 cases, females accounted for 59.5% and inquirers from 11 to 40 years old, 89.4%. The number of prescription drugs, nonprescription drugs, sanitary aids, emergency drugs, functional health foods, and others were 428 (44.8%), 328 (34.3%), 31 (3.3%), 2 (0.2%), 122 (12.8%), and 44 (4.6%), respectively. Questions for drugs acting on alimentary tract and metabolism took up 27.4% followed by those on nervous system, 13.6% and anti-infectives for systemic use, 12.2%. Pharmacist consultation regarding drug information, drug interaction, and adverse reaction occupied 47.9%, 15.2%, and 12.3%, respectively. Conclusion: Health counseling through online is predicted to increase steadily, so pharmacists should broaden their boundaries beyond off-line pharmacies to meet social needs.

• 한국터널지하공간학회 논문집
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• 제10권3호
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• pp.257-267
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• 2008

우리나라에서 흔히 채택하고 있는 배수형 터널은 배수시스템 열화 혹은 수압작용에 따라 누수가 발생하는 문제점을 내포하고 있다. 누수는 소량일 경우 외관으로 드러나지 않아, 육안으로 확인할 단계가 되면 이미 라이닝 손상 혹은 설비에 영향을 미치는 상황이 되어 초기에 인지하고 대책을 마련하는 것이 매우 중요하다. 그러나 운영 중인 배수터널의 누수거동을 확인하기 위해서는 터널을 훼손하여 배면을 조사하여야 하는데, 이는 터널 유지관리상 허용되기 어렵다. 본 연구에서는 비파괴 물리탐사법인 전기비저항 탐사법을 이용하여 터널의 방수막을 훼손하지 않고, 누수여부를 파악하는 새로운 시도를 하였다. 모형 라이닝을 제작하여 습윤정도, 혹은 열화에 따른 누수거동을 탐사한 결과 전기비저항 탐사법이 라이팅 배수기능모니터링 혹은 누수조사에 유용하게 활용될 수 있음을 확인하였다. 또한 이 방법은 라이닝 누수 보수공사 후, 추가 누수여부의 조사 및 보수공사 점검에도 유용하게 활용될 수 있음을 보였다.

• 수산해양기술연구
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• 제51권4호
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• pp.512-519
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• 2015

A historical tragic disaster happened by capsizing the passenger ship Sewol at South Western Sea of Korea in 16, April 2014. The ship which left Incheon harbour to bound for Jeju port passed Maengol strait and reached to approach of Byung Pung island, and then capsized and sank with a sudden inclination to the portside in the mean time of starboard the helm. In this time, the ship which has very poor stability without sufficient ballast waters and with over loading cargo listed port side caused by the centrifugal force acting to the outside of turning. A lot of cargoes not fastened moved to the port side consequently, and the ship came to beam end to capsize and sank in the end. No crews including especially captain would offer their own duties in a such extremely urgent time, as a result, enormous number of victims broke out including a lot of student. In this report, author carried out some calculation on the factors which influenced on the stability of the ship, i.e. the ship's speed, the rudder angle, the weight of cargoes and distance of movement, the surface effect of liquid in the tank. We found out that the most causes of capsize were the poor stability with heavy cargoes and insufficient amount of ballast water against the rule, and the cargoes unfastened moved one side to add the inclination as well. Above all, the owner be blamable because of the illegally operating the ship without keeping the rule.

• 한국멀티미디어학회논문지
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• 제16권9호
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• pp.1098-1108
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• 2013

기존 MMORPG 게임 캐릭터 생성 시스템의 커스텀마이징(Customizing) 방식이 주류를 이루고 있으나 자유도에 맞추어 발생된 캐릭터들은 너무 개성적인 표현이 대두되어 상대적으로 캐릭터에 대한 상대 유저의 캐릭터의 인지판단이 모호해지는 단점이 존재한다. 따라서 본 연구는 인지적 판단이 가능하고 동시에 선호적 디자인 요소를 캐릭터 디자인에서 적절히 응용하여 각각 캐릭터의 감성 특징을 더 쉽게 표현할 수 있고 캐릭터의 상호정보를 더 쉽게 판단할 수 있는 디자인프로세스를 제안한다. 또한 본 논문은 2012년 6월 기초조형학연구 13권 3호에 게제된 "게임 캐릭터 인지성과 선호도에 관한 연구"에 관한 심화연장연구로써 기초연구를 토대로 실증적 실험 및 분석결과를 제시하여 MMORPG 게임 캐릭터에 대한 인지성과 선호도 사이에 어떠한 관계 형성이 이루어지는지를 파악하고 각 직업군 캐릭터의 인지특성의 효율적인 표현 방법을 제안한다.

• 한국지능시스템학회논문지
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• 제1권1호
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• pp.9-25
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• 1991

This tutorial paper has been written for biologists, physicians or beginners in fuzzy sets theory and applications. This field is introduced in the framework of medical diagnosis problems. The paper describes and illustrates with practical examples, a general methodology of special interest in the processing of borderline cases, that allows a graded assignment of diagnoses to patients. A pattern of medical knowledge consists of a tableau with linguistic entries or of fuzzy propositions. Relationships between symptoms and diagnoses are interpreted as labels of fuzzy sets. It is shown how possibility measures (soft matching) can be used and combined to derive diagnoses after measurements on collected data. The concepts and methods are illustrated in a biomedical application on inflammatory protein variations. In the case of poor diagnostic classifications, it is introduced appropriate ponderations, acting on the characterizations of proteins, in order to decrease their relative influence. As a consequence, when pattern matching is achieved, the final ranking of inflammatory syndromes assigned to a given patient might change to better fit the actual classification. Defuzzification of results (i.e. diagnostic groups assigned to patients) is performed as a non fuzzy sets partition issued from a "separating power", and not as the center of gravity method commonly employed in fuzzy control. It is then introduced a model of fuzzy connectionist expert system, in which an artificial neural network is designed to build the knowledge base of an expert system, from training examples (this model can also be used for specifications of rules in fuzzy logic control). Two types of weights are associated with the connections: primary linguistic weights, interpreted as labels of fuzzy sets, and secondary numerical weights. Cell activation is computed through MIN-MAX fuzzy equations of the weights. Learning consists in finding the (numerical) weights and the network topology. This feed forward network is described and illustrated in the same biomedical domain as in the first part.

• Environmental Analysis Health and Toxicology
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• 제10권1_2호
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• pp.37-46
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• 1995

The purpose of this research is to estimate a safe environmental level of human exposure to thresholding-acting toxicants in drinking water and recommend the acceptable levels and management plans for maintaining good quality of drinking water' and protecting health hazard. This research has been funded as a national project for three years from 1992 to 1995. This study(the second year, 1993-1994) was conducted to monitor 39 species of noncarcinogenic chemicals such as volatile organic compounds(VOCs), polynuclear aromatic hydrocarbens(PAHs), pesticides and heavy metals of drinking water at some area in six cities of Korea, and evaluate health risk due to these chemicals through four main steps (hazard identification, exposure assessment, dose-response assessment and risk characterization) of risk assessment in drinking water. In hazard identification, 39 species of non-carcinogenic chemicals were identified by the US EPA classification system. In the step of exposure assessment, sampling of tap water from the public water supply system had been conducted from 1993 to 1994, and 39 chemicals were analyzed. Inclose-response assessment for non-carcinogens, reference doses(RfD) and lifetime health advisories(HAs) of lifetime acceptable levels were calculated. In risk characterization of detected chemicals, the hazard quotients of noncarcinogens were less than one except those of manganese and iron in D city.

• 한국해양환경ㆍ에너지학회지
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• 제4권3호
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• pp.65-73
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• 2001

본 논문에서는 현수선 모델에 기초를 둔 해석방법을 사용하여 부유쓰레기 차단막에 작용하는 흐름에 의한 장력 및 항력을 계산하였다. 흐름에 의한 항력우 차단막의 법선방향으로만 작동하여 차단막에 걸리는 장력은 일정하다고 가정하였다. 계산 모델로 차단막이 흐름방향과 대칭으로 설치된 경우와 비대칭으로 설치된 경우를 다루었다. 형상계수와 설치각도와 같은 차단막의 설치형상을 바꿔가면서 차단막에 작용하는 장력과 항력의 변화를 살펴보았다 계산 결과는 형상계수가 증가함에 따라 장력계수도 커지며 형상계수가 큰 범위에서는 장력계수의 증가폭이 커짐을 보여주고 있다 또한 차단막을 흐름방향과 비대칭으로 설치하였을 때 경사각도를 증가시키면 장력계수가 줄어든다는 사실을 발견하였다 계산모델은 한강 지류인 탄천에 설치한 길이 200m의 부유쓰레기 차단막에 적용하였다. 계산결과에 의하면 차단막 양 끝단에 설치한 앵커블록이 견딜 수 있는 최대 흐름속도는 2m/sec이다.

• 대한기계학회논문집A
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• 제25권5호
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• pp.805-815
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• 2001

Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure). High IOP is caused by the aqueous humor which is produced consistently but not drained due to malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are three methods to treat glaucoma-using medicines, surgical operation, and using implant device. The first and second methods are not long acting, so the use of implants is increasing in these days in order to drain out the aqueous humor compulsory. However, though conventional implants have a capability of pressure regulation, they cannot maintain IOPs desired for different patients, and too much aqueous humor are usually drained, to cause hypotony. To solve these problems, it is needed to develop a new implant which is capable of controling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper, firstly, we make an analysis of the operation of a conventional implant using a bond graph and show defects and limitations of the conventional valve analytically. Secondly, we design and analyze a valve actuator considering actuation principles, resistance elements, control methods, and energy sources focused on power saving problem. Finally, using simulations the possibility of the proposed valve actuator is investigated.