• 경영과정보연구
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• 제36권3호
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• pp.113-130
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• 2017

본 연구는 2006년부터 2015년까지 거래소에 상장된 비금융기업을 대상으로 아시아 지역의 직접투자가 기업가치에 어떠한 영향을 미치는지 실증분석한다. 또한 기업의 현금보유가 아시아 시장 직접투자와 기업가치 사이의 관계를 조절하는 효과를 규명한다. 최근 위험관리의 일환으로 기업은 현금보유량을 늘리고 있으나 현금보유가 대리인 문제를 야기하여 기업가치에 부정적인 영향이 존재한다. 이때 기업이 해외직접투자와 같은 활발한 투자활동을 감행할 경우, 적절한 자금이 적시에 공급되어 해외직접투자의 성공 가능성을 높임과 동시에 현금보유의 대리인 문제가 완화되는 효과가 발생한다. 따라서 현금보유가 해외직접투자와 기업가치 사이의 관계를 조절하는가를 살펴본다. 분석을 위하여 해외직접투자가 가장 활발하게 일어나고 있는 중국, 베트남 시장을 대상으로 한국 상장기업의 직접투자기업 개수를 설명변수로 하고, 현금보유를 조절변수로 설정하여 기업가치의 대리변수로서 토빈 큐를 종속변수로 하여 고정효과모형을 이용하여 분석하였다. 분석 결과, 중국과 베트남 직접투자는 기업가치에 양(+)의 관계를 갖는 것으로 나타났으며, 현금보유가 해외직접투자와 기업가치의 양(+)의 관계를 조절하는 것으로 나타났다. 본 논문의 실무적 함의점으로 아시아 지역 직접투자와 기업가치 사이의 관계를 파악함으로써 직접투자를 적절히 유지하는 것이 기업의 가치를 높일 수 있다는 점을 제시한다. 이와 더불어 현금보유가 해외직접투자를 시행하는 기업에 있어서 효과적 투자공급의 역할을 하게 되어 기업가치에 긍정적 영향을 미치는 것으로 제시할 수 있다.

• 아동학회지
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• 제31권3호
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• pp.51-66
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• 2010

This study examined the effects of parental attachment and peer attachment in elementary school children upon early adolescent delinquency. The participants were 2,844 taken from data from the Korean Youth Panel Survey (KYPS). Data from secondary questionnaires data on parent and peer attachment, problem behavior, delinquent peers, and delinquency were used for this study. Data were analyzed by means of a Structural Equation Model using AMOS 5.0. Our results indicated that, firstly, parental attachment was negatively related to problem behavior for both male and female adolescents, whereas peer attachment was positively related to problem behavior only for males, but not for females. Secondly, problem behavior in childhood has a direct effect on adolescent delinquency, which also can be indirectly mediated by contact with delinquent peers. In conclusion, the path model from parental and peer attachment in early childhood to adolescent delinquency was supported only in the case of males.

• 대한조선학회논문집
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• 제46권3호
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• pp.232-248
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• 2009

Numerical methodology to solve ship springing problem, which is basically fluid-structure interaction problem, was explored in this study. Solution of this hydroelasticity problem was sought by coupling higher order B-spline Rankine panel method and finite element method in time domain, each of which is introduced for fluid and structure domain respectively. Even though varieties of different combinations in terms of numerical scheme are possible and have been tried by many researchers to solve the problem, no systematic study regarding the characteristics of each scheme has been done so far. Here, extensive case studies have been done on the numerical schemes especially focusing on the iteration method, FE analysis of beam-like structure, handling of forward speed problem and so on. Two different iteration scheme, Newton style one and fixed point iteration, were tried in this study and results were compared between the two. For the solution of the FE-based equation of motion, direct integration and modal superposition method were compared with each other from the viewpoint of its efficiency and accuracy. Finally, calculation of second derivative of basis potential, which is difficult to obtain with accuracy within grid-based method like BEM was discussed.

• 대한산업공학회지
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• 제17권2호
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• pp.131-142
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• 1991

The concept of criterion function is proposed as a framework for comparing the geometric and computational characteristics of various nonlinear programming approaches to linear programming such as the method of centers, Karmakar's algorithm and the gravitational method. Also, we discuss various computational issues involved in obtaining an efficient parallel implementation of these methods. Clearly, the most time consuming part in solving a linear programming problem is the direction finding procedure, where we obtain an improving direction. In most cases, finding an improving direction is equivalent to solving a simple optimization problem defined at the current feasible solution. Again, this simple optimization problem can be seen as a least squares problem, and the computational effort in solving the least squares problem is, in fact, same as the effort as in solving a system of linear equations. Hence, getting a solution to a system of linear equations fast is very important in solving a linear programming problem efficiently. For solving system of linear equations on parallel computing machines, an iterative method seems more adequate than direct methods. Therefore, we propose one possible strategy for getting an efficient parallel implementation of an iterative method for solving a system of equations and present the summary of computational experiment performed on transputer based parallel computing board installed on IBM PC.

• 한국항해학회지
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• 제20권4호
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• pp.59-70
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• 1996

A berth assignment problem has a direct impact on assessment of charges made to ships and goods. In this paper, we concerned with of fuzzy mathematical programming models for a berth assignment problem to achieved an efficient berth operation in a fuzzy environment. In this paper, we focus on the berth assignment programming with fuzzy parameters which are based on personal opinions or subjective judgement. From the above point of view, assume that a goal and a constraint are given by fuzzy sets, respectively, which are characterized by membership functions. Let a fuzzy decision be defined as the fuzzy set resulting from the intersection of a goal and constraint. This paper deals with fuzziness in all parameters which are expressed by fuzzy numbers. A fuzzy parameter defined by a fuzzy number means a possibility distribution of the parameters. These fuzzy 0-1 integer programming problems are formulated by fuzzy functions whose concept is also called the extension principle. We deal with a berth assignment problem with triangular fuzzy coefficients and propose a branch and bound algorithm for solving the problem. We suggest three models of berth assignment to minimizing the objective functions such as total port time, total berthing time and maximum berthing time by using a revised Maximum Position Shift(MPS) concept. The berth assignment problem is formulated by min-max and fuzzy 0-1 integer programming. Finally, we gave the numerical solutions of the illustrative examples.

• Journal of Information Science Theory and Practice
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• 제10권4호
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• pp.23-37
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• 2022

The pandemic of Coronavirus disease (COVID-19) has contributed more challenges for mothers as the family's primary caregiver in overcoming the widespread infection. Pandemic-related information is essential for mothers to reduce uncertainty as well as to maintain the health of family members during this unprecedented situation. Adopting the framework of the Situational Theory of Problem Solving, this study extends the theory by, first, testing the mediating role of COVID-19 anxiety on mothers' information seeking and information forwarding, referred to as active communication action of problem solving, as well as preventive behavior; and second, by predicting the effect of information seeking on preventive behavior. Referring to an online survey from 371 Indonesian mothers, the findings suggest that in terms of direct effect, only problem recognition was found to have no significant effect on situational motivation. The results suggest that Indonesian mothers perceive COVID-19 as personally relevant so that they are motivated to solve the problem by seeking and forwarding related information. In addition, COVID-19 anxiety was found to play a significant role in predicting information seeking, information forwarding, and preventive behavior. The result of this study is expected to give insights for risk communicators and health professionals in Indonesia in communicating COVID-19, particularly to mothers.

• 한국소음진동공학회논문집
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• 제14권3호
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• pp.253-263
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• 2004

The problem considered in this paper is about the collocation of sensor and actuator for the active control of sound and vibration. It is well-known that a point collocated sensor-actuator pair offers an unconditional stability with very high performance when it is used with a direct velocity feedback (DVFB) control, because the pair has strictly positive real (SPR) property. In order to utilize this SPR characteristics, a matched piezoelectric sensor and actuator pair is considered. but this pair suffers from the in-plane motion coupling problem with the out-of-plane motion due to the piezo sensor and actuator interaction. This coupling phnomenon limits the stability and performance of the matched pair with DVFBcontrol. As a new alternative, a point sensor and distributed piezoelectric actuator pair is also considered, which provides SPR property in all frequency range when the pair is implemented on a clamped-clapmed beam. The use of this sensor-actuator pair is highly expected for the applications to more practical active control of sound and vibration systems with the DVFB control strategy.

• 한국산학기술학회논문지
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• 제10권5호
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• pp.955-961
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• 2009

현재 소형 휴대용 배터리의 용량 증가에 따라 배터리 부피가 커지는 문제를 가지고 있다. 이러한 문제를 해결하기 위해 직접 메탄올 연료전지가 대안으로 떠오르고 있다. 본 논문에서는 직접 메탄올 연료전지를 상온 상태에서 자연 대류 방식으로 공기를 공급하고, 메탄올의 농도와 유량의 변화에 대한 특성을 분석하였다. 분석 결과 저 농도의 메탄올에서는 수소 이온의 확산 속도 지연에 따른 분극현상이 발생하였고, 메탄올의 공급량이 높을수록 전지 Cell의 냉각 효과가 발생하여 출력이 감소한다.

• 한국CDE학회논문집
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• 제17권1호
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• pp.35-44
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• 2012

Many automobile manufacturers are doing experiment on manufacturing environments by using an augmented reality technology. However, system layout and process simulation by using the virtual reality technology have been performed actively more than by using the augmented reality technology in practical use so far. Existing automobile assembly by using the augmented reality requires the precise calibrating work after setting the robot because the existing augmented reality system for the automobile assembly system configuration does not include the end tip deflection and the robot joints deflection due to the heavy weight of product and gripper. Because the robot is used mostly at the automobile assembly, the deflection problem of the robot joint and the product in the existing augmented reality system need to be improved. Moreover camera lens calibration has to be performed precisely to use augmented reality. In order to improve this problem, this paper introduces a method of the software based calibration to apply the augmented reality effectively to the automobile assembly system. On the other hand, the camera lens calibration module and the direct compensation module of the virtual object displacement for the augmented reality were designed and implemented. Furthermore, the developed automobile assembly system oriented AR-system was verified by the practical test.

• International Journal of Advanced Culture Technology
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• 제5권2호
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• pp.19-25
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• 2017

The research is to identify social networks of problems that have an influence on the quality of ageing people's lives by using social network analysis, based on the premise that there are differences in networks of ageing problems in urban and rural areas. From analyzing network of ageing people's problems using NodeXL, vertices in the networks of both urban and rural areas are well-connected. For urban areas, financial poverty is the core problem related to the quality of life. It has direct connections with illness and health, family responsibility, housing, role loss in community, and employment, which have positive or negative interactions with the quality of older people's lives. For rural areas, on the other hand, role loss in community is the major problem. It has direct connections with the elderly abuse, financial poverty, leisure activity, divorce, isolation and loneliness from society, education, and suicide. As a result, the research shows that the problems of ageing people have strong linkages and interactive effects with a structure of network, and the networks are different depending on types of places for living.