• Bulletin of the Korean Chemical Society
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• 제8권5호
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• pp.414-418
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• 1987

Electrochemical reduction of dibenzoylmethane was studied on mercury electrode by means of cyclic voltammetry, polarography and potentiostatic measurements in ethanol-water system. In acidic solutions monomeric pinacol was produced by irreversible two-electron process while monomeric and dimeric pinacol were competitively produced by the same process in neutral solution. However, in basic solution the dimeric pinacol was mostly produced through radical by irreversible one-electron transfer process. Mechanisms of the reduction of dibenzoylmethane are deduced from Tafel slope, pH dependance and reaction order with respect to the concentration of dibenzoylmethane in the solution of various pH.

• 산업경영시스템학회지
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• 제19권39호
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• pp.75-80
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• 1996

Fuzzy approaches used to solve MONLP(Multiobjective Nonlinear Programming Problem) are based on the max-min method of fuzzy sets theory However, since the min operator noncompensatory, these approaches can not guarentee an efficient solution to the problem. In this paper, we presents an algorithm for finding the aggregation operator to find efficient solution. In particular, our presented algorithm is guarentee an efficient solution. On the basis of proposed algorithm, an illustrative numerical example is presented.

• Journal of applied mathematics & informatics
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• 제42권2호
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• pp.291-303
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• 2024

In this paper, we consider a feedforward network of overloaded multiclass processor sharing queues and we give a fluid model solution under the condition that the system is initially empty. The main theorem of the paper provides sufficient conditions for a fluid model solution to be linear with time. The results are illustrated through examples.

• 에너지공학
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• 제7권2호
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• pp.231-240
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• 1998

CFC계 냉매에 의한 지구환경문제 야기, 여름철 피크전력의 증가뿐만 아니라 열회수 시스템에서의 손실로 인하여 고성능 흡수냉동시스템의 개발은 이 문제를 해결할 수 있는 유망한 방법중의 하나이다. 하수처리수를 이용한 흡수식 냉동시스템은 환경보호와 에너지 보존의 측면에서 유용하다. 본 연구에서는 2중효용 병렬 및 직렬방식에 대한 사이클 시뮬레이션 해석을 수행하였다. 신작동매체로 LiBr+LiI+LiCl+LiNO3 용액을 선택하였다. 이 연구의 주된 목적은 흡수기와 응축기의 냉각수로써 하수처리수를 효과적으로 이용할 수 있는 가능성을 평가하는 것과 2중효용 병렬과 직렬방식에 영향을 미치는 신작동매체의 특성을 파악하고 최적설계조건을 찾고자 하는 것이다. 본 연구에서 사이클 시뮬레이션을 통하여 신작동매체를 사용하는 흡수식 냉동기의 특성을 파악했으며 이를 기존의 LiBr 수용액을 사용하는 흡수식 냉동기와 비교평가하였다. 신작동매체를 이용한 흡수식 냉동기는 LiBr 수용액을 사용하는 경우보다 COP의 향상과 시스템의 소형화가 가능하다는 것을 알 수 있었다.

• 대한수학교육학회지:학교수학
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• 제16권1호
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• pp.1-17
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• 2014

본 연구의 목적은 한 문제를 다양한 방법으로 해결할 수 있는 문제와 이에 대한 채점방법을 활용하여 학생들의 수학적 창의성을 측정함으로써 수학적 창의성을 측정할 수 있는 기반을 구축하는 것이다. 이를 위해 초등 5학년 학생 10명을 대상으로 다양한 방법으로 해결할 수 있는 문제를 활용하여 검사를 실시하여 수학적 창의성을 측정하였다. 수학적 창의성 측정을 위하여 창의성의 하위 요소인 유창성, 융통성, 독창성을 바탕으로 '새롭고, 가치 있는' 수학적 산출물을 평가할 수 있는 채점방법을 구축하여 활용하였다. 분석 결과, 수학적 창의성 점수는 학생 간 편차가 크게 나타났다. 또한 문항별로도 수학적 창의성 점수에서 차이가 나타나, 수학 학습 내용에 따라 학생들의 수학적 창의성 분석의 필요성이 대두되었다. 본 연구의 채점방법에 따르면, 유창성이 높을수록 수학적 창의성이 높았다. 그렇지만 '새롭고, 가치 있는' 수학적 창의성의 특성을 부각시키는 채점방법에 의해 유창성과 융통성이 증가할수록 답의 희소성이 낮아져 상대적으로 독창성 점수를 얻기가 어려웠다. 따라서 답의 희소성과 수학적인 측면에서 답의 가치를 동시에 고려하는 독창성 판단의 준거를 만들 필요가 대두되었다.

• 산업경영시스템학회지
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• 제45권4호
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• pp.42-52
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• 2022

North Korea continues to upgrade and display its long-range rocket launchers to emphasize its military strength. Recently Republic of Korea kicked off the development of anti-artillery interception system similar to Israel's "Iron Dome", designed to protect against North Korea's arsenal of long-range rockets. The system may not work smoothly without the function assigning interceptors to incoming various-caliber artillery rockets. We view the assignment task as a dynamic weapon target assignment (DWTA) problem. DWTA is a multistage decision process in which decision in a stage affects decision processes and its results in the subsequent stages. We represent the DWTA problem as a Markov decision process (MDP). Distance from Seoul to North Korea's multiple rocket launchers positioned near the border, limits the processing time of the model solver within only a few second. It is impossible to compute the exact optimal solution within the allowed time interval due to the curse of dimensionality inherently in MDP model of practical DWTA problem. We apply two reinforcement-based algorithms to get the approximate solution of the MDP model within the time limit. To check the quality of the approximate solution, we adopt Shoot-Shoot-Look(SSL) policy as a baseline. Simulation results showed that both algorithms provide better solution than the solution from the baseline strategy.

• Advances in nano research
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• 제16권3호
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• pp.231-249
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• 2024

When the amplitude of the vibrations is equivalent to that clearance, the vibrations for small amplitudes will really be significantly nonlinear. Nonlinearities will not be significant for amplitudes that are rather modest. Finally, nonlinearities will become crucial once again for big amplitudes. Therefore, the concrete panel system may experience a big amplitude in this work as a result of the high temperature. Based on the 3D modeling of the shell theory, the current work shows the influences of the von Kármán strain-displacement kinematic nonlinearity on the constitutive laws of the structure. The system's governing Equations in the nonlinear form are solved using Kronecker and Hadamard products, the discretization of Equations on the space domain, and Duffing-type Equations. Thermo-elasticity Equations. are used to represent the system's temperature. The harmonic solution technique for the displacement domain and the multiple-scale approach for the time domain are both covered in the section on solution procedures for solving nonlinear Equations. An effective data-driven solution is often utilized to predict how different systems would behave. The number of hidden layers and the learning rate are two hyperparameters for the network that are often chosen manually when required. Additionally, the data-driven method is offered for addressing the nonlinear vibration issue in order to reduce the computing cost of the current study. The conclusions of the present study may be validated by contrasting them with those of data-driven solutions and other published articles. The findings show that certain physical and geometrical characteristics have a significant effect on the existing concrete panel structure's susceptibility to temperature change and GPL weight fraction. For building construction industries, several useful recommendations for improving the thermo-mechanics' behavior of structural concrete panels are presented.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.304-308
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• 2008

The optimal design of two stage evaporation & absorption system which is related to the large temperature difference system was investigated numerically in the absorption refrigeration system. The concentrations at inlet & oulet of absorber are 62.9% and 56.9%, but in two stage absorption system the values are 62.2% and 56.2%. Therefore strong solution & weak solution became diluted than the standard value. The amount of weak solution circulation can be reduced in absorption refrigeration system, and the sensible heat load is more reduced to enhance the COP of system. As UAR is increased, COP becomes larger, and this means the role of top section is more important than bottom section in two stage evaporation & absorption system. But the increase of COP becomes slower at 0.7 of UAR ratio. The performance of Type2 is higher than Type1 in COP with the flow direction of cooling waters. This phenomena is due to the active absorption of vapor -absorption & lower temp. cooling water is more effective. The pressure at bottom section becomes higher & that at top section becomes lower and therefore the circulation rate can be diminished more.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.203-211
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• 2008

The optimal design of two stage evaporation & absorption system which is related to the large temperature difference system was investigated numerically in the absorption refrigeration system. The concentrations at inlet & oulet of absorber are 62.9% and 56.9%, but in two stage absorption system the values are 62.2% and 56.2%. Therefore strong solution & weak solution became diluted than the standard value. The amount of weak solution circulation can be reduced in absorption refrigeration system, and the sensible heat load is more reduced to enhance the COP of system. As UAR is increased, COP becomes larger, and this means the role of top section is more important than bottom section in two stage evaporation & absorption system. But the increase of COP becomes slower at 0.7 of UAR ratio. The performance of Type2 is higher than Type1 in COP with the flow direction of cooling waters. This phenomena is due to the active absorption of vapor -absorption & lower temp. cooling water is more effective. The pressure at bottom section becomes higher & that at top section becomes lower and therefore the circulation rate can be diminished more.

• 한국융합학회논문지
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• 제10권1호
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• pp.35-43
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• 2019

본 논문은 산업입지정보시스템을 개선하기 위한 연구이다. 산업입지정보시스템 현황 및 문제점을 분석하고 시스템을 개선하기 위한 목표 및 방향을 설정하였으며, 이를 바탕으로 시스템 개선 적용 방안을 마련하여 보았다. 산업입지정보시스템은 현재 노후화된 H/W 및 상용 S/W 사용으로 인한 유지보수 비용 문제, 오래된 개발 프레임워크 사용으로 시스템 문제 발생 시 즉각적인 대응 어려운 문제, 정보검색 및 제공에도 한계가 있는 것으로 분석되었다. 따라서 본 논문에서는 시스템 개선을 위한 전자정부 표준 프레임워크 적용 및 Open Source S/W 도입을 통한 시스템이 가지고 있는 문제점에 대한 해결 방법과 정보 연계 강화 및 시각화 기능 적용을 제시하였으며, 향후 산업입지정보시스템 개선을 위한 시스템 분석/설계 및 개발 시 도움이 될 것으로 판단된다.