• 소음진동
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• 제11권1호
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• pp.147-155
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• 2001

This paper is concerned with the real-time automatic tuning of the multi-input multi-output positive position feedback controllers for smart structures by the genetic algorithms. The genetic algorithms have proven its effectiveness in searching optimal design parameters without falling into local minimums thus rendering globally optimal solutions. The previous real-time algorithm that tunes a single control parameter is extended to tune more parameters of the MIMO PPF controller. We employ the MIMO PPF controller since it can enhance the damping value of a target mode without affecting other modes if tuned properly. Hence, the traditional positive position feedback controller can be used in adaptive fashion in real time. The final form of the MIMO PPF controller results in the centralized control, thus it involves many parameters. The bounds of the control Parameters are estimated from the theoretical model to guarantee the stability. As in the previous research, the digital MIMO PPF control law is downloaded to the DSP chip and a main program, which runs genetic algorithms in real time, updates the parameters of the controller in real time. The experimental frequency response results show that the MIMO PPF controller tuned by GA gives better performance than the theoretically designed PPF. The time response also shows that the GA tuned MIMO PPF controller can suppress vibrations very well.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.109-114
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• 1997

In this paper, we present an output feedback $H^\infty$controller design method and derive the sufficient condition of the bounded real lemma for linear systems with multiple delays in states. For state delayed systems, sufficient conditions for the existence $\kappa$-th order $H^\infty$controllers are given in terms of three linear matrix inequalities(LMIs). Furthermore, we show how to construct such controllers from the positive definite solutions of their LMIs and given an example to illustrate the validitiy of the proosed design procedure.

• 대한수학회보
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• 제43권4호
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• pp.693-701
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• 2006

Using Minimax principle and Linking theorem in critical point theory, we prove the existence of two nontrivial solutions for the following second order superlinear difference systems $$(P)\{{\Delta}^2x(k-1)+g(k,y(k))=0,\;k{\in}[1,\;T],\;{\Delta}^2y(k-1)+f(k,\;x(k)=0,\;k{\in}[1,\;T],\;x(0)=y(0)=0,\;x(T+1)=y(T+1)=0$$ where T is a positive integer, [1, T] is the discrete interval {1, 2,..., T}, ${\Delat}x(k)=x(k+1)-x(k)$ is the forward difference operator and ${\Delta}^2x(k)={\Delta}({\Delta}x(k))$.

• 수산경영론집
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• 제51권1호
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• pp.67-79
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• 2020

The purpose of this study is to propose a policy improvement plan by analysis of the extinction risk factors reflecting the specificity of fishing villages, fishing village support policies, and settlement conditions of fishing villages as one of the solutions to the immediate problem of fishing village extinction. The results of the study show the higher the level of number of fishing ports, number of returning rural population, and housing diffusion rate, the dependent variable extinction risk index was a positive effect while vacant house ratio and aged house ratio was analyzed to be in was a negative (-) relationship with the dependent variable.The policy implications through this study were to prepare an effective policy to reduce the risk of extinction, to improve urgent settlement conditions, and to prepare a condition to convert returning rural population into fishery population.

• 디지털콘텐츠학회 논문지
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• 제11권2호
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• pp.129-134
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• 2010

현재 초등학교 교육과정의 컴퓨터교육에서는 실기 위주의 수업방식과 학습자 중심의 개별화 수업을 강조하고 있다. 본 연구에서는 다수의 학습도우미를 활용한 시범-실습 교수법을 적용하여 초등학교 컴퓨터 교과 학습 단점 중 하나인 학생들의 개개인의 다양한 능력차이로 인해 교사의 시연 속도에 맞추어 따라가기 힘든 학생들의 개별 지도 확대를 통해 이 문제를 해결하였다. 이를 위해 초등학교 4학년 3개 학반을 선정하여 교사주도의 시범 실습으로 수업 한 집단, 한명의 학습도우미 활용한 시범 실습으로 수업 한 집단, 그리고 다수의 학습도우미를 활용한 시범 실습으로 수업 한 집단으로 구분하여 세 집단간의 과제수행능력 및 자기효능감, 컴퓨터 학습에 대한 호응도 및 흥미도를 비교 분석하였다. 그 결과, 다수의 학습도우미를 활용한 시범 실습 수업 집단이 과제수행능력, 자기효능감, 그리고 학습도우미 활용 학습에 대한 흥미도와 호응도에서 긍정적인 영향을 미치는 것으로 나타났다.

• 대한수학회지
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• 제57권3호
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• pp.747-775
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• 2020

In this work we investigate the nonlocal elliptic equation with critical Hardy-Sobolev exponents as follows, $$(P)\;\{(-{\Delta}_p)^su={\lambda}{\mid}u{\mid}^{q-2}u+{\frac{{\mid}u{\mid}^{p{^*_s}(t)-2}u}{{\mid}x{\mid}^t}}{\hspace{10}}in\;{\Omega},\\u=0{\hspace{217}}in\;{\mathbb{R}}^N{\backslash}{\Omega},$$ where Ω ⊂ ℝ^N is an open bounded domain with Lipschitz boundary, 0 < s < 1, λ > 0 is a parameter, 0 < t < sp < N, 1 < q < p < p^∗_s where $p^*_s={\frac{N_p}{N-sp}}$, $p^*_s(t)={\frac{p(N-t)}{N-sp}}$, are the fractional critical Sobolev and Hardy-Sobolev exponents respectively. The fractional p-laplacian (-∆_p)^su with s ∈ (0, 1) is the nonlinear nonlocal operator defined on smooth functions by $\displaystyle(-{\Delta}_p)^su(x)=2{\lim_{{\epsilon}{\searrow}0}}\int{_{{\mathbb{R}}^N{\backslash}{B_{\epsilon}}}}\;\frac{{\mid}u(x)-u(y){\mid}^{p-2}(u(x)-u(y))}{{\mid}x-y{\mid}^{N+ps}}dy$, x ∈ ℝ^N. The main goal of this work is to show how the usual variational methods and some analysis techniques can be extended to deal with nonlocal problems involving Sobolev and Hardy nonlinearities. We also prove that for some α ∈ (0, 1), the weak solution to the problem (P) is in C^1,α(${\bar{\Omega}}$).

• 보건행정학회지
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• 제9권4호
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• pp.41-64
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• 1999

The major concern for this research is to discuss and to offer some solutions to bring the effectiveness of existing notifiable diseases reporting system over the physicians' attitudes of reporting, the actual condition of performance and the reasons of inertia in notifiable diseases reporting through examining the physicians of medical institutions in nationwide such as pediatrics, internal medicine and family medicine. The actual conditions of notifiable communicable diseases(NCD) reporting was surveyed by mail objectifying an internal medicine, pediatrics and family medicine in nationwide on the basis of stratified random sampling method divided into the classification of medical institutions and areas. As a result of survey. the rate of respondents showed 145 persons from physicians, 105 persons from hospitals. 120 persons from general hospitals, and 51 persons from tertiary hospitals. The total number of respondents were 421 and was rated 59.0 %. The analysis of collected survey went through a descriptive analysis primarily to grasp physicians' attitudes on the notifiable communicable diseases reporting, and then upon the dependent variables. Following are major findings obtained form the data analysis. 1. The results of a descriptive analysis on physicians' attitudes towards reporting NCD were as follows: First, the respondents who didn't know that yellow fever is reporting NCD were 11.0% of clinic, 10.5% of hospital. 5.0% of general hospital. 11.8% of tertiary hospital. and in case of hepatitis B, were 26.9% of clinic, 35.2% of hospital. 35.0% of general hospital. 23.5% of tertiary hospital. Second, The rate of physicians' knowledge on penalties of not reporting the NCD by their medical institution were 35.2% of clinic, 45.7% of hospital. 36.7% of general hospital. 62.7% of tertiary hospital. Third, among the no-reporting physicians in whole, the major reason of not reporting NCD were uncertainty of diagnosis(78.9%), no need to report(46.4%), no adequate actions from PHC(29.1%), no knowledge of the cases being notifiable ones in the order of their frequencies(30.4%), meddling from PHC(29.1%), concerning of patient's privacy(26.3%). 2. To analyze the characteristics related to the physicians' behaviors to report NCD, univariate and multiple logistic regression analyses were applied to the variables related to physician, 4 medical facility, PHC, and reporting system. The result were as follows: First, the result of the univariate analysis on physicians' attitude to report NCD and characteristics related to reporting in odds ratio was in the case of hospital. 3.4 times higher positive responses on physicians' attitude to report NCD came up as compared to the clinic. Second, the result of the univariate analysis on physicians' action of reporting NCD and characteristics related to reporting by the classification of medical institutions showed that the odds ratio of hospital was 2.3 times, the odds ratio of general hospital was 2.0 times, the odds ratio of tertiary was 6.8 times significantly higher than clinic. And the medical institution with significantly higher positive attitudes rate by multiple logistic regression analysis was hospital that rated 2.5 times significantly higher than clinic. Also in the PHC related characteristics of reporting, the rate of action in reporting NCD was significantly higher in medical institution that were endowed with the good condition of reporting. In multiple logistic regression analysis, the medical institution that has a good conditions of reporting showed a significantly higher positive rate on the action of reporting than the others.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.53-56
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• 2000

그로벌최적화문제(Global optimization problem)의 부류인 다목적선형계획법 ( MOLP ) (Multiple objective linear programming)에서 결정된 유효해집합(a set of efficient solutions)위에서 선형함수 최적화문제 ( Ρ )는 해집합이 볼록집합이 아니므로(nonconvex set) 일반적인 선형계획법을 활용하기가 어렵다. 현재까지 ( Ρ )의 최적화를 위해서 유효해집합의 모든 꼭지점(extreme point)를 찾거나 일련의 선형계획문제들을 최적화하여 최적해를 찾는 접근방법들이 있다. 이러한 방법들에는 ( MOLP )의 해집합의 차원(dimension)이 커짐에 따라 문제해결이 실제적으로 가능하지 않는 경우가 많다. 본 연구는 주어진 선형함수와 다목적선형함수들간 관계를 고찰하여 선형목적함수를 구성하고 그 목적함수를 이용하여 주어진 문제 (Ρ) 의 최적해를 찾는 선형계획적 접근방법을 제안한다.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.577-582
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• 2020

The performance of a teacher has an important role in the success of education in general. This study aims to determine the factors that affect the decline in teacher performance in one of the junior secondary schools in Indonesia. Based on the literature review, four exogenous variables were identified, namely, training, utilization of information technology, intellectual intelligence, and emotional intelligence. This study uses primary data, collected from a questionnaire distributed to respondents. The questionnaire items are measured using a Likert scale. The sample in this study were all teachers at MTS Darul Falah Sirahan, totaling 32 people. The analysis technique used in testing the hypothesis of this study is multiple regression analysis. Statistical product and service solutions are used as analysis tools. The results of this study indicate that only the variable 'utilization of information technology' has a positive and significant effect. However, the variables 'training,' 'intellectual intelligence,' and 'emotional intelligence' did not have a significant effect. This finding contradicts the literature in general. Therefore, this study recommends improving training methods, both those carried out internally by schools and by related agencies, and schools still need to optimize guidance and potential for teacher's intelligence in improving performance.

• Advances in Computational Design
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• 제2권4호
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• pp.313-331
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• 2017

In this study, teaching-learning based optimization (TLBO) is improved by incorporating model of multiple teachers, adaptive teaching factor, self-motivated learning, and learning through tutorial. Modified TLBO (MTLBO) is applied for simultaneous topology, shape, and size optimization of space and planar trusses to study its effectiveness. All the benchmark problems are subjected to stress, displacement, and kinematic stability constraints while design variables are discrete and continuous. Analyses of unacceptable and singular topologies are prohibited by seeing element connectivity through Grubler's criterion and the positive definiteness. Performance of MTLBO is compared to TLBO and state-of-the-art algorithms available in literature, such as a genetic algorithm (GA), improved GA, force method and GA, ant colony optimization, adaptive multi-population differential evolution, a firefly algorithm, group search optimization (GSO), improved GSO, and intelligent garbage can decision-making model evolution algorithm. It is observed that MTLBO has performed better or found nearly the same optimum solutions.