• 대한수학회지
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• 제35권1호
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• pp.115-126
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• 1998

We study the optimal control problem of system governed by retarded functional differential $$ x'(t) = A_0 x(t) + A_1 x(t - h) + \\ulcorner\ulcorner\ulcorner_{-h}^{0} a(s)A_2 x(t + s)ds + B_0 u(t) $$ in Hilbert space H. After the fundamental facts of retarded system and the description of condition so called a weak backward uniqueness property are established, the technically important maximal principle and the bang-bang principle are given. its corresponding linear system.

• 대한수학회지
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• 제53권5호
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• pp.1019-1036
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• 2016

In this paper, we study the existence of solutions and $L^2$-regularity for fractional order retarded neutral functional differential equations in Hilbert spaces. We no longer require the compactness of structural operators to prove the existence of continuous solutions of the non-linear differential system, but instead we investigate the relation between the regularity of solutions of fractional order retarded neutral functional differential systems with unbounded principal operators and that of its corresponding linear system excluded by the nonlinear term. Finally, we give a simple example to which our main result can be applied.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.213-230
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• 2002

We deal with the approximate controllability for semilinear systems with time delay in a Hilbert space. First, we show the existence and uniqueness of solutions of the given systems with the mere general Lipschitz continuity of nonlinear operator f from $R\;\times\;V$ to H. Thereafter, it is shown that the equivalence between the reachable set of the semilinear system and that of its corresponding linear system. Finally, we make a practical application of the conditions to the system with only discrete delay.

• 대한수학회보
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• 제55권2호
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• pp.479-497
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• 2018

This paper deals with an optimal control on semilinear stochastic functional differential equations with Poisson jumps in a Hilbert space. The existence of an optimal control is derived by the solution of proposed system which satisfies weakly sequentially compactness. Also the stochastic maximum principle for the optimal control is established by using spike variation technique of optimal control with a convex control domain in Hilbert space. Finally, an application of retarded type stochastic Burgers equation is given to illustrate the theory.

• 한국세라믹학회지
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• 제21권2호
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• pp.143-148
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• 1984

In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

• 한국정보교육학회:학술대회논문집
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• 한국정보교육학회 2010년도 하계학술대회
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• pp.143-149
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• 2010

최근 정신지체아들을 위한 음악교육의 중요성이 크게 부각되고 있으나 그들의 인지적 정의적 결함으로 인해 종래의 일반적인 음악수업 방식만으로는 음악 인지를 발달시키는 학습을 기대하기 어렵다. 이에 본 연구에서는 MMCP (Manhattanville Music Curriculum Program)이론에 근거한 정신지체아의 음악인지능력 (음악 동일성, 음악 유목화, 음악 서열화)을 향상시키기 위한 컨텐츠를 설계하였다. MMCP 이론은 음악의 본질을 이해시키며 특징음악 (18~19C의 음악) 만을 취급하는 음악이 아닌 모든 민족의 음악문화를 이해하고 포함하는 보다 포괄적인 음악교육이다. 본 시스템으로 기대할 수 있는 효과로는 첫째, 정신지체장애인의 음악적 인지 발달 뿐 아니라 인지적, 신체적, 사회적, 정서적 발달을 고양시킬 수 있다. 둘째, 정신지체장애인을 위한 개별화 음악교육이 가능하다. 셋째, 능동적이고 상호작용적인 음악교육이 가능하다.

• Korean Chemical Engineering Research
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• 제52권1호
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• pp.68-74
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• 2014

해수-담수 염도 차 발전을 위한 압력지연삼투(pressure-retarded osmosis: PRO) 시스템의 나권형(spiral wound) 모듈에서 공급채널과 유도채널 사이의 입구 압력차의 영향이 수치적으로 연구되었다. 그리하여 막을 통한 물과 용질-플럭스들의 변화와 전력이 예측되었다. 막을 통한 물-플럭스의 크기는 두 채널 간 입구 압력차가 증가할수록 x축 방향으로 감소하고 y축 방향으로 증가하였다. 반면에 막을 통한 용질-플럭스의 크기는 반대의 경향을 보였다. 공급채널 내 유체의 농도는 y축 방향으로 크게 증가하였고, 유도채널 내 농도는 x축 방향으로 크게 감소하였다. 본 시스템에서 입구 압력차가 1~11 atm일 때 공급채널 내 유량은 8~13% 가량 감소하였고, 유도채널 내 유량은 그만큼 증가하였다. 전력밀도는 입구 압력 차가 증가할수록 증가하다가 감소하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제3권2호
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• pp.81-97
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• 1999

This paper deals with the time optimal control problem for the retarded semilinear system by using the construction of fundamental solution in case where the principal operators are unbounded operators.

• 대한수학회지
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• 제36권2호
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• pp.317-332
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• 1999

In this paper we deal with the optimal control problem for the semilinear functional differential equations with unbounded delays. We will also establish the regularity for solutions of the given system. By using the penalty function method we derive the optimal conditions for optimality of an admissible state-control pairs.

• East Asian mathematical journal
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• 제19권1호
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• pp.133-150
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• 2003

This paper will show that the relation (1.1) $$L^1({\Omega}){\subset}C_0(\bar{\Omega}){\subset}H_{p,q}$$ if 1/p'-1/n(1-2/q')<0 where p'=p/(p-1) and q'=q/(q-1) where $H_{p.q}=(W^{1,p}_0,W^{-1,p})_{1/q,q}$. We also intend to investigate the control problems for the retarded systems with $L^1(\Omega)$-valued controller in $H_{p,q}$.