• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.560-564
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• 1996

A mixed H$^{2}$/$H^{\infty}$ controller design method for linear systems with time delay in all variables and parameter uncertainties in all system matrices is proposed. Robust $H^{\infty}$ performance and H$^{2}$ performance condition that accounts for model-matching of closed loop system and disturbance rejection is also derived. With expressing uncertain system with linear fractional transformation form, we transform the robust stability and performance problem to the H$^{2}$/$H^{\infty}$ optimization problem and design a mixed H$^{2}$/$H^{\infty}$ controller. Using the proposed method, mixed H$^{2}$/$H^{\infty}$ controller for underwater vehicle with time delay and parameter variations are designed. Simulations of a design example with hydrodynamic parameter variations and disturbance are presented to demonstrate the achievement of good robust performance.t performance.ance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.177-181
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• 2008

Recently, amount of High-Rise Mixed-use Building is Increasing based on Preference of comfortable residence and good view. Government policies were turned to prefer about High-Rise Mixed-use Building because of decreased real estate Condition. But these changes have revealed that it has many maintenance problems for example- efficiency, economic, environmental problems. This paper suggests that the Database System based on various alternatives and real case. And it will be a tool in the scientific decision and value analysis from the facility management to make optimized decision.

• 한국분무공학회지
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• 제2권3호
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• pp.25-31
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• 1997

This experiment was undertaken to investigate the spray characteristics of the conventional injection system and the ultrasonic energy added injection system. Test fuels include light oil and mixed light-BC oil. The mixed light-BC oil was injected at the normal temperature$(20^{\circ}C)$ and the high temperature$(95{\pm}2^{\circ}C)$ and injection pressure was $120kg/cm^2$. Sauter mean diameter was measured under the variation of the spray distance. To measure the droplet size, we used the Malvern system 2600C. Droplet size distribution was analyzed from the result data of Malvern system. It is also found that the condition of the ultrasonic energy added injection and high temperature injection generates the smaller droplets than that of the conventional injection.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 가을 학술발표회 논문집
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• pp.217-224
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• 1998

• 한국항해항만학회지
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• 제46권5호
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• pp.458-470
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• 2022

As the 4th industrial revolution progresses, the application of several cutting-edge technologies such as the Internet of Things, big data, and mixed reality (MR) in relation to autonomous ships is being considered in the maritime logistics field. The aim of this study was to apply the concept of a digital twin model based on Human Machine Interaction (HMI) including a digital twin model and the role of an operator to a ship. The role of the digital twin is divided into information provision, support, decision, and implementation. The role of the operator is divided into operation, decision-making, supervision, and standby. The system constituting the ship was investigated. The digital twin system that could be applied to the ship was also investigated. The cloud-based digital twin system architecture that could apply investigated applications was divided into ship data collection (part 1), cloud system (part 2), analysis system/ application (part 3), and MR/mobile system (part 4). A Mixed Reality device HoloLens was used as an HMI equipment to perform a simulation test of a digital twin system of an 8 m battery-based electric propulsion ship.

• 한국전산구조공학회논문집
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• 제21권6호
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• pp.571-578
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• 2008

IT기술의 발전에 따른 각종 산업에서의 유비쿼터스 도입이 이루어지고 있다 특히 자동차 산업에서 유비쿼터스 환경 도입을 위한 연구가 활발히 진행되고 있으며, BMW의 경우 유비쿼터스 환경 기반의 운전자지원시스템을 연구한바 있다. 조선산업에서 유비쿼터스 환경을 구축하고자 유비쿼터스 기반의 혼합현실을 제시한다. 혼합현실은 현실과 가상이 융합된 환경으로 현실에 기반을 두었을 때 증강현실이라고 하며, 이것은 현실세계에 가상의 물체를 오버랩하여 보여줌으로써 보다 현실감을 높여주는 기술이다. 따라서 본 논문에서는 해양구조물에서의 효과적인 검자 지원을 위하여 증강현실 기술을 활용하였으며 프로토 타입을 구축해 봄으로 그 활용 가능성을 판단해 보고자 한다.

• 대한화학회지
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• 제55권3호
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• pp.379-384
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• 2011

[ $25^{\circ}C$ ] 순수 물에서 음이온성 계면활성제인 DBS(sodium dodecyl benzenesulfonate)와 SDS(sodium dodecylsulfate) 그리고 비이온성 계면활성제인 Brij 30(polyoxyethylene(4) lauryl ether) 사이의 혼합미셀화에 대한 임계미셀농도(CMC)와 반대이온의 결합상수값(B)을 전도도법과 표면장력계법으로 측정하였다. 이와 같이 측정한 CMC값에 비이상적 혼합미셀화 모델을 적용함으로써 여러 가지 열역학적 함수값($X_i,\;{\gamma}i,\;C_i,\;a_i^M,\;{\beta}$ 및 ${\Delta}H_{mix}$)들을 계산하여 상호 비교분석하였다. 그 결과, SDS는 DBS보다 Brij 30과 더욱 강한 상호작용을 이루었으며, SDS/Brij 30 혼합계면활성제가 이상적 혼합미셀화로부터 가장 큰 음의 벗어남을 보였다. 그리고 SDS/DBS 혼합계면활성제는 거의 이상적 혼합미셀화를 이루는 것으로 나타났다.

• 동력기계공학회지
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• 제18권6호
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• pp.126-132
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• 2014

The P-T characteristics of mixed refrigerant in thermostatic expansion valve sensing bulb were studied using R-134a and R-410A refrigerant. The characteristics of mixed refrigerant were investigated according to pressure variation and the variation of composition ratio of R-134A and R-410A in the temperature range of $-15^{\circ}C{\sim}15^{\circ}C$. The Thermodynamic characteristic values of the mixed refrigerants were identified using the characteristic value analysis program of mixed refrigerant(Refrop v9.0, NIST). The P-T characteristics in the case of the mixing ratio of 90:10 for R-410A and R-134A were the same result as R-22. And the physical properties showed similar results with R-22. The Maximum operating pressure(MOP) of mixed refrigerant showed a tendency to decrease with decreasing the mixing ratio of additive gases($N_2$ or He) gases. The characteristics in the case of the mixing ratio of 80:1 for mixed refrigerant and additive gases were the similar result as Reference refrigerant.(R-22 MOP, Sporlan company) In addition $N_2$ and He, both showed the same results. It was able to confirm that a MOP on the thermostatic expansion valve sensing bulb can be maintained by adjusting the mixing ratio of mixed refrigerant gases and additive gases.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.144-149
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• 2022

A cryogenic Mixed Refrigerant Joule-Thomson refrigeration cycle was designed to be applied to the semiconductor etching process with non-flammable constituents. 3-stage cascade refrigerator, single mixed refrigerant Joule-Thomson refrigerator, and 2-stage cascade type mixed refrigerant Joule-Thomson refrigerator are analyzed to figure out the coefficient of performance. Non-flammable mixture of argon(Ar), tetrafluoromethane(R14), trifluoromethane (R23) and octafluoropropane(R218) were utilized to analyze the refrigeration cycle efficiency. The designed refrigeration cycle was adapted to cool down the coolant of HFE7200(Ethoxy-nonafluorobutane, C₄F₉OC₂H₅) with certain constraints. Maximum coefficient of performance of the refrigeration system is obtained as 0.289 for the cooling temperature lower than -100℃. The detailed result of the coefficient of performance according to the mixture composition is discussed in this study.

• 산업공학
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• 제10권3호
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• pp.209-216
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• 1997

This mixed push and pull production system defines that all stages are not ordered by either of the production systems. Some stages are ordered by a push-type production system and the other stages are ordered by a pull-type production system. A decision support system is built by using a combination of optimization program and the "tunable" SIMAN discrete-event simulation for the implementation of an optimally mixed production system. Finding this optimal system requires 6 CPU hours for the case study on a Pentium. Both the simulation and optimization model are validated with a case study of Phoenix company that manufactures transmitters. This paper uses survey from experts in this company for evaluation and validation of this system.