• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.53-56
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• 2000

The problem ( Ρ ) of optimizing a linear function d$\^$T/x over the set of efficient set for a multiple objective linear program ( Μ ) is difficult because the efficient set is nonconvex. There some interesting properties between the objective linear vector ｄ and the matrix of multiple objectives C and those properties lead us to establish criteria to solve ( Ρ ) with a linear program. In this paper we investigate a system of the linear equations C$\^$T/${\alpha}$=d and construct two linearly independent positive vectors ${\mu}$, ν such that ${\alpha}$=${\mu}$-ν. From those vectors ${\mu}$, ν, solving an weighted sum linear program for finding an efficient extreme point for the ( Μ ) is a way to get an optimal solution ( Ρ ). Therefore our theory gives an easy way of solving nonconvex program ( Ρ ) with a weighted sum linear program.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.92-95
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• 1999

The design problem of the control system is the ability to synthesize controller that achieve robust stability and robust performance. The paper explains the Finite Inclusions Theorem (FIT) by the procedure namely FIT synthesis. It is developed for synthesizing robustly stabilizing controller for parametrically uncertain system. The fundamental problem in the study of parametrically uncertain system is to determine whether or not all the polynomials in a given family of characteristic polynomials is Hurwitz i.e., all their roots lie in the open left-half plane. By FIT it can prove a polynomial is Hurwitz from only approximate knowledge of the polynomial's phase at finitely many points along the imaginary axis. An example shows the simplicity of using the FIT synthesis to directly search for robust controller of parametrically uncertain system by way of solving a sequence of systems of linear inequalities. The systems of inequalities are solved via the projection method which is an elegantly simple technique fur solving (finite or infinite) systems of convex inequalities in an arbitrary Hilbert space. Results from example show that the controller synthesized by FIT synthesis is better than by H$\sub$$\infty$/ synthesis with parametrically uncertain system as well as satisfied the objectives for a considerably larger range of uncertainty.

• Journal of the Korean Home Economics Association
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• v.39 no.9
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• pp.153-174
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• 2001

The objectives of this study were to examine the propensity and to analyze some determinants of complaining behavior about the educational services of private institutes. The survey was conducted by means of self-administered questionnaire with 546 university students Living in Seoul and Cheongjoo. They had an experience of studying in the educational services of private institutes in recent two years. Major findings were as following: (1) The propensity of private complaining behavior about the educational services of private institutes averages 3.36 points out of 5. This score is beyond the middle slightly. Whereas the propensity of pubic complaining behavior is very low. (2) According to the discriminant analysis, tuition fee, information supplied for solving the dissatisfaction, and altitude about the complaining behavior are the determinants to distinguish between complaining/non complains behavior group of private complaining behavior. (3) Information supplied for solving the dissatisfaction, kindness of the stars, the establishment, the way of making tuition fees, the degree of awareness of cost, the attitude about complaining behavior, the confidence of success for complaining behavior are the determinants to distinguish between complaining/non complains behavior group of public complaining behavior.

• 대한공업교육학회지
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• v.30 no.2
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• pp.3-11
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• 2005

The purpose of this study is to measure the level of the key competencies of industrial high school students and to use it as the basic material so as to improve the key competencies. The subject was 359 industrial high school students(boys: 244, girls: 115) in Seoul, Daejeon, Gwangju, and Busan. The instrument used to measure the key competencies is that developed by Cheol-Young Jeong, which was partly revised with the help of a group of experts. The results of this study showed some of skills were below an average of 3.0, which were writting skill(M=2.85) and speaking skill(M=2.96) in communication skills, logical thinking(M=2.98) in problem solving skills, leadership skill(M=2.88) in interpersonal skills, and self-improvement skill(M=2.96) and the spirit of public service(M=2.93) in self-management and self-improvement skills. But technology skills were above an average of 3.0. And it appeared that technology skills(P=.023) depended on having a certificate or not, and so did communication skills(P=.020) and problem solving skills(P=.034) on the types of a course(employment or entrance into a college). So, to strengthen the key competencies which appeared below an average of 3.0 in this study, not only does the curriculum of industrial high schools need to be reorganized, but systematic strengthening program of key competencies should also be developed.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.4
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• pp.328-333
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• 2014

A hybrid particle-mesh method based on the vorticity-velocity formulation for solving the incompressible Navier-Stokes equations is a combination of the Vortex-In-Cell(VIC) method for convection and the penalization method for diffusion. The key feature of the numerical methods is to determine velocity and vorticity fields around a solid body on a temporary grid, and then the time evolution of the flow is computed by tracing the convection of each vortex element using the Lagrangian approach. Assuming that the vorticity and velocity fields are to be computed in time domain analysis, pressure fields are estimated through a complete set of solutions at present time step. It is possible to obtain vorticity and velocity fields prior to any pressure calculation since the pressure term is eliminated in the vorticity-velocity formulation. Therefore, pressure field is explicitly treated by solving a suitable Poisson equation. In this paper, we propose a simple way to numerically implement the vorticity-velocity-pressure formulation including a penalty term. For validation of the proposed numerical scheme, we illustrate the early development of viscous flows around an impulsive started circular cylinder for Reynolds number of 9500.

• Research in Community and Public Health Nursing
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• v.8 no.1
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• pp.133-143
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• 1997

This study measures the subjectivity of nursing students' experience in community fields through community nursing practice. The purpose of this study is as follows: 1) to find out typologies based on opinions and attitudes toward community nursing practice. 2) to describe the characteristic of each type. 3) to provide alternative strategies for solving community nursing practice problems. A Q-Methodological method was used for that purpose. As a research method, Q-statements were collected through indepth interviews and review of the current literature. For this study 34 Q-statements were selected. 24 nursing students were subjects for the research. The 24 nursing students sorted 34 Q-statements using the principle of Forced Normal Distribution. The principle of Forced Normal Distribution, which has nine scales to measure individual opinions, was called, a Q- Factor Analysis by using a PC Quanl Program to supply the material. According to the results of this study, there were three categories of opinion concerning community nursing practice. The first type is the realistic problem-oriented approach: the second type is the self-responsibility or pursuit of life meaning approach: the third type is the group approach for problem solving. As a result, we need to develop and revise a more realistic way of community nursing practice for nursing students. Finally, the result of this study will provide to the educational program alternative strategies for community nursing practice for nursing students.

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.123-133
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• 2001

With ever-change and increasingly competitive business environments, firms strive to employ a variety of marketing strategies and execution in order to survive in the market. Such effects would be paid off in the right way only when management of the firms perform marketing activities focusing on long term effectiveness, which would drive company profits up and keep them for long. Demands of customers are being changed and varied. And in this circumstance, it become a main issue of management that the company should produce and sell products according to the customer demands. With these trends, each company has been concentrating effects on generalization of product development technique and distinction of service for customer. In this result with the advantage of mass marketing and database marketing have been drawing attentions from company. Also the internet connected around the world completely diminished the limit of time and distance and company have enveloped keen competition out of each nation and continent in the world market. To fulfill these demands of customer, they need a concept of eCRM(Web based Customer Relationship Management), and go from selling products and services, or gathering customer requests, up to the phase of solving customer's problem by real time or previous action. With the help of internet, the frequency and speed of the problem solving has improved greatly.

• Proceedings of the Safety Management and Science Conference
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• 2001.11a
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• pp.65-71
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• 2001

With ever-change and increasingly competitive business environments, firms strive to employ a variety of marketing strategies and execution in order to survive in the market. Such effects would be paid off in the right way only when management of the firms perform marketing activities focusing on long term effectiveness, which would drive company profits up and keep them for long. Demands of customers are being changed and varied. And in this circumstance, it become a main issue of management that the company should produce and sell products according to the customer demands. With these trends, each company has been concentrating effects on generalization of product development technique and distinction of service lot customer In this result with the advantage of mass marketing and database marketing have been drawing attentions from company. Also the internet connected around the world completely diminished the limit of time and distance and company have enveloped keen competition out of each nation and continent in the world market. To fulfill these demands of customer, they need a concept of eCRM(Web based Customer Relationship Management), and go from selling products and services, or gathering customer requests, up to the phase of solving customer's problem by real time or Previous action. With the help of Internet, the frequency and speed of the problem solving has improved greatly.

• Journal of The Korean Association For Science Education
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• v.24 no.1
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• pp.146-156
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• 2004

The purpose of this study is to look at the use of heuristics when a sixth grader solves a problem. Two research questions have been formulated: The similarities and differences in the use of heuristics when a student solves two problems that are science-knowledge-based and not science-knowledge-based, and the different types of prompts. A male sixth grade student participated in this study. All of the information for the study was collected in three interviews. The interviews began with observing the student's solving problems. The student was asked how and why he solved problem that way. There were some interactions between the researcher and the student during the interview procedures. As results of this study, eight general heuristics were used in both solutions: Check examples for support of an idea: check examples for exceptions to an idea: restate the problem: compare to known examples or patterns: make a hypothesis; check the relevance of other information present; use analogy: and recognize patterns/similarity. There seemed to be more similarities than differences in the type of general heuristic that were used in the two problem solutions. The student was systematic and consistent in his use of the general use of heuristics. Five types of interviewer prompts were detected in the two problem solutions, directional cues, modeling, clarity, problem posing, metacognition and validation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.50-59
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• 2014

In this paper, we develop an efficient approach to solve a multiple-item budget-constraint newsboy problem with a reservation policy. A conventional approach for solving such problem utilizes an approximation for the evaluation of an inverse of a Gaussian cumulative density function when the argument of the function is small, and a heuristic method for finding an optimal Lagrangian multiplier. In contrast to the conventional approach, this paper proposes more accurate method of evaluating the function by using the normalization and an effective numerical integration method. We also propose an efficient way to find an optimal Lagrangian multiplier by proving that the equation for the budget-constraint is in fact a monotonically increasing function in the Lagrangian multiplier. Numerical examples are tested to show the performance of the proposed approach with emphases on the behaviors of the inverse of a Gaussian cumulative density function and the Lagrangian multiplier. By using sensitivity analysis of different budget constraints, we show that the reservation policy indeed provides greater expected profit than the classical model of not having the reservation policy.