• 한국정밀공학회지
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• 제12권5호
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• pp.57-68
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• 1995

A general procedure for the numerical solution of coupled, nonlinear, differential two-point boundary-value problems, solutions of which are crucial to the controller design, has been developed and demonstrated. A fixed-end-points, free-terminal-time, optimal-control problem, which is derived from Pontryagin's Maximum Principle, is solved by an extension of Davidenko's method, a differential form of Newton's method, for algebraic root finding. By a discretization process like finite differences, the differential equations are converted to a nonlinear algebraic system. Davidenko's method reconverts this into a pseudo-time-dependent set of implicitly coupled ODEs suitable for solution by modern, high-performance solvers. Another important advantage of Davidenko's method related to the time-optimal problem is that the terminal time can be computed by treating this unkown as an additional variable and sup- plying the Hamiltonian at the terminal time as an additional equation. Davidenko's method uas used to produce optimal trajectories of a single-degree-of-freedom problem. This numerical method provides switching times for open-loop control, minimized terminal time and optimal input torque sequences. This numerical technique could easily be adapted to the multi-point boundary-value problems.

• 한국학교수학회논문집
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• 제3권1호
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• pp.189-200
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• 2000

The purpose of this thesis is that the students understand the sentence stated math problems closely related to the real life and adapted the right solving strategies try to find the solution to a problem. The following research problem were proposed. 1. How repeated thinking lessons develop the understanding of problems and influence the usage of correct problem solving strategies and extensions of problem solving. 2. There are how much differences of achievement for each type of sentence stated problems by using comparative analysis of upper class, intermediate class, and lower class for each level between the experimental and comparative classes. In order to conduct this research the classes were divided into three different level - upper class, intermediate class and lower class. Each level include an experimental class and a comparative class. The two classes (experimental class and comparative class) of the same level were tested on the basis of class division record with the experimental class repeated learning papers for two weeks were used to guide the fixed thinking algorism for each sentence stated math problems. Eight common problems were chosen from a variety of textbooks : number calculation problems, velocity-distance-time problems, the density of a mixture, benefit problems, distribution problems, problems about working, ratio problems, the length of a figure problems. After conducting this research experiment The differences in achievement level between the experimental class and comparative class, were compared and analyzed through achievement tests made from the achievement test papers with seven problems, which were worth seventy points (total score). The conclusions of this thesis are as follows: Firstly, leaning activities through the usage of repeated learning papers for each level class produce an even development of achievement level especially in the case of the upper class learners, they have particular differences (between experimental class and comparative class) compared to the intermediate level and lower classes. Secondly, according to the analysis about achievement development each problems, learners easily accept the strategies of solution through the formula setting up to the problem of velocity -distance-time, and to the density of the mixture they adapted the picture drawing strategies interestingly, However each situation requires a variety of appropriate solution strategies. Teachers will have to employ other interesting solution strategies which relate to real life.

• 센서학회지
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• 제6권1호
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• pp.6-15
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• 1997

이 논문은 빔의 구조를 갖거나 멤브레인의 구조를 갖는 써모파일 센서의 다목적 최적설계에 관한 연구이다. 연구대상의 써모파일 센서는 $Si_{3}N_{4}/SiO_{2}$ 박막위에 알루미늄과 다결정 실리콘을 사용하여 열전쌍을 형성하고, 박막중심부에 $RuO_{2}$를 사용하여 적외선 흡수부를 만들어 중심부와 실리콘림부 사이의 온도차이에 따른 Seebeck 효과에 의한 유기전압을 감지하는 센서를 대상으로 하였다. 최적설계의 목적함수는 센서의 감도, 검출능 (detectivity) 및 열시정수를 대상으로 하였다. 패키지를 고려하여 모델링을 하였으며, 기존의 식의 고찰에 의한 단순 설계방법이 아닌 수학적 계획법을 사용한 다목적 최적화 방법을 이용하여 최적해를 구하였다. 최종적인 최적설계 수식화에는 퍼지계획법에서 사용되는 소속함수를 정의하여 설계자가 우선적으로 신뢰할 수 있는 해를 구 할 수 있도록 하였다. 또한, 제한조건으로서 주위 온도변화에 따른 센서의 출력전압변화를 포함시켜 실제 사용되는 환경을 고려하였다.

• 유변학
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• 제11권2호
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• pp.97-104
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• 1999

본 연구에서는 전기장의 인가 유무에 따라 유체의 유변성질이 가역적으로 변화하는 ER(electro-rheological) 유체를 이용하여 CD-ROM(compact disc-read only memory) 마운트를 구성한 후 피딩 시스템의 진동제어를 수행하였다. 이를 위하여 우선 특수화학처리된 전분계 ER유체를 조성하였으며, 전단모드 및 유동모드하에서 전기장에 따른 항복응력을 실험적으로 도출하였다. 도출된 ER유체의 항복응력에 근거하여 복합모드형 CD-ROM 마운트를 설계, 제작하였다. 제작된 ER CD-ROM 마운트의 진동절연 특성을 주파수 영역에서 고찰하였으며 기존의 고무마운트 성능과 비교하였다. 나아가서 제안된 마운트를 장착한 정보저장기기 드라이브 피딩 시스템의 동적 모델링을 수행하였으며, 진동제어를 위한 스카이훅 제어기를 설계하였다. 컴퓨터 시뮬레이션을 통하여 여러 외란(가진) 조건에 따른 피딩 시스템의 진동제어 성능을 주파수 및 시간 영역에서 고찰하였다.

• 한국의상디자인학회지
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• 제15권3호
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• pp.119-135
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• 2013

The purpose of this study was to investigate the relationship between consumption values of preschooler clothing and purchasing satisfaction, company brand loyalty and involvement of preschooler clothing with the mothers of preschoolers. An online survey was adapted as methodology of this study. The collected 323 questionnaires were collected and statistically analyzed. The nine consumption value of preschooler clothing(vicarious satisfaction value, social value, functional value, convenient value, economic value, coordination value, aesthetic value, distinctive value, and fashionable value) resulted from the analysis of survey. Purchasing satisfaction, company brand loyalty, involvement of preschooler clothing was Uni-dimensional. Statistical analysis was performed with frequency analysis, descriptive statistics, exploratory factor analysis, multi-group analysis, confirmatory factor analysis, bivariate correlation analysis, distribution, structural equation, cluster analysis, independent sample t-test, one-way analysis of variance. The results of this study are as follows. In the consumption value of preschooler clothing influencing on the purchasing satisfaction was evaluated depending on the involvement of preschooler clothing group (high-involvement group, low-involvement group). In the low-involvement group, the most significant consumption value of preschooler clothing are economic value, convenient value, social value in order of importance; though in the high-involvement group, aesthetic value, social value, economic value in order of importance. Also the brand royalty was more affected by the purchasing satisfaction in the high-involvement group than in the low-involvement group. In conclusion, the relations of consumption value of preschooler clothing with purchasing satisfaction, company brand loyalty, involvement of preschooler clothing was established in study. The significances of this study is to provide the market segmentation strategy depending on the characteristics of preschooler clothing consumers and establish the information and direction to increase the company brand royalty and purchasing satisfaction.

• 대한가정학회지
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• 제50권7호
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• pp.49-58
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• 2012

The main aim of the current study is to examine the effects of mothers' parental beliefs and mother-child attachment on school-aged children's time management and life management skills through the mediation effects of children's self-regulation. Study participants included a total of 317 fifth- and sixth-grade children at elementary schools located in Seoul and Gyeong-gi area, and their 317 mothers. Children and mothers completed questionnaires and Structural Equation Modeling was adapted as the main analysis technique. The findings were the following: First, mothers' parental beliefs that emphasize the child's independence were significantly related to greater self-regulation ability in children, indicated by cognitive, motivational, and behavior regulation. Second, better quality of mother-child attachment perceived by children was also found to predict greater self-regulation in children. Third, children's self-regulation was strongly related to time and life management skills. When the child is better at self control, the child showed greater management skills, both in time and everyday life. Finally, as hypnotized, the test yielded a significant mediation effect of self-regulation in the association from mothers' parental beliefs and mother-child attachment to children's time and life management skills. The findings suggested the important role of parental beliefs about child rearing and attachment between mother and child in developing self-regulation and management skills of school-aged children.

• 한국정보시스템학회지:정보시스템연구
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• 제24권2호
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• pp.139-162
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• 2015

Purpose This study reviews technology acceptance research in the information system area and consumer behavior research in the marketing area, sets characteristics of convergence products, personality of consumers and communication channels as main concepts and demonstrates their effects on 'relative level of attraction' and 'intent to adoption. Design/methodology/approach The survey was conducted against potential consumers who have the intent to purchase electric communication media products that provides a variety of functions and service, such as a smart TV, a tablet PC and a smart watch. All items were adapted from previous literature and revised as appropriate the purpose of this study and measured on a 7-point Likert scale with answer choices ranging from "strongly disagree" (1) to (7) "strongly agree." Totally, 300 respondents participated in the survey. Out of the 276 respondents, incomplete or invalid 24 were discarded. With them, SPSS 18.0 and AMOS 20.0 for structural equation modeling were used for the analysis. Findings Main findings are as followed;- First, it is found that 'interrelationship of technology' and 'functional diversification' of convergence products has positive effects on relative level of attraction. Second, perceived behavior control has significant effects on the intent to adoption convergence products. Third, communication through mass media has positive effects on making potential consumers feel attraction about products while there is no relationship with the intent to a. On the other hands, it is demonstrated that there is no relationship influential relationship between communication through interpersonal channels and relative level of attraction while communication through interpersonal channels has significant effects on the intent to adoption.

• Journal of Radiation Protection and Research
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• 제9권1호
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• pp.26-32
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• 1984

원자발전소의 가동에 따른 기체상 방사성물질의 방출로부터 주변주민이 받는 피해는 정상상태와 사고 경우로 나눠서 해석하게 된다. 정상상태 경우 방사성물질의 대기확산 모델은 주로 연평균 통계치를 사용하는 Gaussian식을 채택하나 사고결과 해석시에는 풍향 풍속의 변화를 추적하는 실시간(real time) 확산모델을 이용한다. 본고에서는 고려 원자력발전소의 정상가동에 따른 $1977{\sim}1982$년 6개년에 걸친 주변주민의 피복 선량을 Gaussian 직선제도 모델에 의한 대기확산인자치로 계산하였으며 사고경우에 대해서 요구되는 대상지역 주변의 대기확산계수 특성치를 구하는 간편한 영상처리방식을 실제 실험을 통해 제시하였다.

• 대한기계학회논문집B
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• 제24권2호
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• pp.204-213
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• 2000

This study deals with jet impingement, which is extensively used in the process industries to achieve intense heating, cooling or drying rates and also widely employed as a test flow for turbulent models due to its complex flow configuration, on a flat plate by numerical methods. In this calculation, the finite volume method was employed to solve the Navier-stokes equation based on the non-orthogonal coordinate with non-staggered variable arrangement. To get a better understanding for the fluid flow and heat transfer characteristics of the turbulent jet impingements, $k-{\varepsilon}-{\overline{v^{'2}}}$ turbulent model was adapted and compared with the experimental data and the result of standard $k-{\varepsilon}$ turbulent model. Numerical calculations were carried out with various flow rates, nozzle to plate distances. In the case of the axisymmetric jet impingement on a flat plate, $k-{\varepsilon}-{\overline{v^{'2}}}$ turbulent model showed better agreement with the experimental data than the standard $k-{\varepsilon}$ turbulent model in the prediction of the mean velocity profiles, the turbulent velocity profiles. the turbulent shear stress and the heat transfer rate. The highest heat transfer rate can be obtained when the impingement occurs within the potential core..

• 한국환경과학회지
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• 제16권2호
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• pp.203-210
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• 2007

The delivery load data obtained from Nakdong river basin are used for developing the model estimating the daily delivery load on the main side streams of Nakdong River. The developed model assesses the daily contamination loads of the main thirteen side streams that contribute to the main stream of Nakdong river. It is developed that the model using the simplified equation that can estimate the daily delivery loads on the side main streams of Nakdong river for a period of having no data of the water quality and flow. The developed model for estimating the daily delivery loads from the main side streams in Nakdong river basin on each item such as BOD, TN, and TP is expressed as Daily delivery load ($\frac{kg}{day}$) = Production load $(\frac{kg}{day}){\times}(1-{\alpha}){\times}(\frac{daily\;runoff}{average\;runoff\;per\;year}){\gamma}$. The estimated values obtained by using the model are almost fit to the calculated values (real data) that have been acquired from the thirteen main side streams in Nakdong river basin. The correlation coefficient values, R, that indicate the correlation between the estimated and the calculated show over 0.7 that mean the estimated values from the used model are adapted to the real data except TN values of Nam-river, Hwang-river, Gam-river, We-river. Especially, the correlation of TP values between the estimated and the calculated implies quite a creditable data to use.