• 한국콘텐츠학회논문지
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• 제17권7호
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• pp.416-424
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• 2017

본 연구는 학습동기가 온라인 협력학습에서 상호작용에 미치는 영향을 분석하고자 한다. 이를 위해 수도권의 A대학에서 교직과목을 수강하는 79명의 대학생들을 대상으로 연구를 수행하였다. 학습동기는 MSLQ를 통해서 내적목적, 외적목적, 과제가치, 학습신념, 시험불안, 자기효능감, 성취목표지향성을 측정하였다. 다음으로 상호작용 수준을 측정하기 위해서 협력과제를 수행하였다. 협력과제를 위한 집단 편성은 4-5명으로 구성하였다. 전공과 관계없이 무선으로 편성하였다. 상호작용의 수준은 빈도와 양적 가치를 부여한 점수로 측정하였다. 수집된 자료는 다중회귀분석(단계적 선택방식)을 실시하여 학습동기가 상호작용의 수준에 미치는 영향을 검증하였다. 그 결과 자기효능감, 외적목표, 과제가치, 성취목표지향성의 수행접근성향과 숙달성향은 상호작용의 빈도와 점수에 정적인 영향이 있었다. 다음으로 시험불안과 성취목표지향성의 수행회피성향은 상호작용의 빈도와 점수에 부적인 영향이 있는 것으로 나타났다. 이와 같은 연구결과를 토대로 온라인 협력학습 상황에서 학습자의 지도에 대한 몇 가지 방안을 제안하였다.

• 대한가정학회지
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• 제48권2호
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• pp.135-144
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• 2010

This study explores whether or not marriage and other family values operate as factors that influence the willingness of women to voluntarily remain ever-single. The study includes as variables the sub-fields of marriage and family values that consist of traditional gender role awareness, freedom in sexual attitude, open outlook on marriage, familism, an acceptance of diverse families, fear of marriage, and assignment of value to extramarital factors. Participants of this study were 259 women in their twenties to forties with no experience of marriage, which were selected from the data used in the Korean Women's Development Institute's Investigation of Single Households(2007). Upon inserting value-related variables and sociodemographic variables into a binomial logistic model for analysis, age, open outlook on marriage, assigned value on extramarital factors, and an acceptance of diverse families were shown to be factors influencing the willingness of women to remain ever-single. That is, as the age spectrum is lower, outlook on marriage is open, more values are granted on the extramarital factors, and the degree of an acceptance of diverse views on family is higher, the chances that women would remain ever-single voluntarily were shown to increase.

• 대한교통학회지
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• 제23권2호
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• pp.117-130
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• 2005

사용자최적통행배정모형과 확률적 사용자최적통행배정모형에서 통행배정의 기준이 되는 경로의 통행시간은 일반적으로 경로를 구성하는 링크 통행시간과 교차로에서 발생하는 회전지체의 합으로 계산된다. 이러한 통행배정방식에는 운전자의 통행행태가 결정되는 주요원인이 될 수 있는 운전자의 실제적 경로인지과정 및 선택과정이 반영되지 않아 편향된 배정결과가 도출되는 가능성이 존재한다. 확률적 사용자최적통행배정모형에서 링크의 통행시간에 대한 통행분포함수로 가정하여 경로인지비용을 반영하려는 노력은 있었으나, 프로빗(Probit) 모형의 단전된 통행시간분포 함수 또는 로짓(Logit)모형의 링크통행시간의 독립성과 같은 이론적으로 불합리한 가정에 의존하여 시도되었지 경로인지비용 반영에 대한 근본적인 결실은 아니었다. 사용자최적통행배정모형에서 경로인지비용을 반영하지 못했던 가장 중요한 이유는 출발지, 도착지, 경로, 링크에 따라 각기 상이한 통행인지비용의 계산 값이 도출되기 때문이다. 따라서 최적의 경로를 선택하기 위해서는 각 기종점을 연결하는 모든 경로의 통행시간을 비교해야 하는 경로열거문제가 대두되며, 교통망의 규모가 증가됨에 따라 지수적으로 증가하는 경로의 수는 계산을 실패하게 되는 원인이 된다. 본 연구에서는 출발지와 목적지 간에 경로를 열거하지 않고 사용자 최적 통행배정모형에 경로인지비용을 반영하는 방안 을 제안하는 것을 목적으로 한다. 이를 위해 본 연구에서 제안하는 방안은 경로의 최소단위를 링크로 정의하고 링크표지기반 최적경로 탐색알고리즘에서 두 링크의 탐색을 진행하면서, 이미 출발지에서 탐색이 진행된 부분경로와의 비교를 통해 경로의 인지비용이 통행비용에 내재되는 방법이다. 종양(2군)으로 나누어 보면 악성 진단율은 각각 37%와 11.6%로 현저한 차이가 있었다. 이들중 조직학적 진단이 가능 하였던 9예의 경우 세포 병리 진단율은 각각 50%(1군)와 20%(2군)로 역시 현저한 차이가 있었다 임상진단이 양성 질환 이었던 예들은 전예에서 세포 병리학적으로 양성으로 진단되어 담즙 세포 병리검사의 임상진단과의 일치율은 27.6%, 특이도는 100%이었다. 이상으로 이 담즙세포 검사의 악성 진단율은 그리높지 않으나, 경피 경간 담즙 배출술로 환자의 증상을 완화 시키면서 부수적으로 진단도 얻을 수 있는 유용한 방법이라 하겠고, 그중 담도유래의 종양군에서 외인성으로 담도를 압박하게 되는 종양군에 비해 현저히 높은 진단율을 보였다.일 수 있는 계기가 되었다고 할 수 있다. did not showed any characterized sign of acute or subacute liver damage or intestine lesion. So it is supposed that there is not any tocixants originated from some molds in fermented Korean domestic Meju which is prepared traditionally in winter.의 배설량은 10배 정도 증가하게 되어 진동만의 오염부하를 가중하게 된다. 진동만은 여름철 빈산소수괴 및 적조가 빈번하게 발생하고 있으므로 미더덕 양식장을 새로이 시설할 경우 오염부하가 가중될 것으로 판단되어, 앞으로 진동만의 양식장 수용능력을 파악하여 적정량의 양식물량이 시설되어야 할 것이다.25 psu에서 가장 높게 나타났다.인

• 대한산업공학회지
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• 제37권1호
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• pp.19-29
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• 2011

Cellular network is comprised of several base stations which serve cellular shaped service area and each base station (BS) is connected to the mobile switching center (MSC). In this paper, the configuration modeling and algorithm of a cellular mobile network with the aim of minimizing the overall cost of operation (handover) and network installation cost (cabling cost and installing cost of mobile switching center) are considered. Handover and cabling cost is one of the key considerations in designing cellular telecommunication networks. For real-world applications, this configuration study covers in an integrated framework for two major decisions: locating MSC and assigning BS to MSC. The problem is expressed in an integer programming model and a heuristic algorithm based on Lagrangian relaxation is proposed to resolve the problem. Searching for the optimum solution through exact algorithm to this problem appears to be unrealistic considering the large scale nature and NP-Completeness of the problem. The suggested algorithm computes both the bound for the objective value of the problem and the feasible solution for the problem. A Lagrangian heuristics is developed to find the feasible solution. Numerical tests are performed for the effectiveness and efficiency of the proposed heuristic algorithm. Computational experiments show that the performance of the proposed heuristics is satisfactory in the quality of the generated solution.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2187-2195
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• 2018

In order to realize the multi-objective control of single-input multi-output nonlinear differential algebraic system (NDAS) and to improve the dynamic characteristics and static accuracy, a design method of nonlinear control with multi-objective feedback (NCMOF) is proposed, the principium of this method to arrange system poles, as well as its nature to coordinate dynamic characteristics and static accuracy of the system are analyzed in detail. Through NCMOF design method, the multi-objective control of the system is transformed into linear space, and then it is effectively controlled under the nonlinear feedback control law, the problem to balance all control objectives caused by less input and more output of the system thus is solved. Applying NCMOF design method to generator excitation system, the nonlinear excitation control law with terminal voltage, active power and rotor speed as objective outputs is designed. Simulation results show that NCMOF can not only improve the dynamic characteristics of generator, but also damp the mechanical oscillation of a generator in transient process. Moreover, NCMOF can control the terminal voltage of the generator to the setting value with no static error under typical disturbances.

• 지역연구
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• 제15권3호
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• pp.15-31
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• 1999

This study examines the economic effects of ill-defined property rights on the resource usage with special reference to the Korean Green Belt. Property rights are considered ill-defined, when their whereabouts are not clearly delineated, they are not assigned to those who utilize them most efficiently, and they are not exercised precisely. If properly, and they are not exercised precisely. If properly rights are ill-defined, it is more likely that economic agents pursue opportunistic and illegal behaviors and even their rational behaviors tend to bring about undesirable outcomes, and social conflicts occur around the assignment of the rights. Upon the completion of a case study, we found that the ill-defined property right system of the Korean Green Belt has, in fact, resulted in several problems in resource usatge. Inefficient land use, compromising reassignment of property rights, the prevalence of illegal activities, huge management costs, and the spread of social conflicts are the problems in question. These problems can be resolved by the realignment of property rights, since they are caused by the ill-defined property right system. To resolve such problems, we need to reassign properly rights so that their delineation may be complete and those who value them highest may exercise the rights, and social justice in terms of wealth distribution may be achieved.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.83-87
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• 2009

HiperLAN/2(High performance radio Local Area Network)에서의 MAC(Media Access Control)프로토콜은 TDMA/TDD(Time Division Multiple Access/Time Division Duplex)기반으로 동작하며, 단말은 RCH(Random CHannel) 구간을 통해 채널 경쟁에서 성공함으로써 데이터 전송 기회를 획득한다. 그러므로 AP(Access Point)는 각 RCH에서 단말들의 채널요청메시지의 성공 및 충돌수에 따라, 다음 프레임에서 최적의 RCH 개수를 동적으로 할당할 수 있어야 한다. 본 논문에서는 HiperLAN/2에서의 성능향상을 위해 충돌과 성공을 고려하여 RCH(Random CHannel)수를 고정적인 값만큼 증감하는 방법을 제안하였다. 제안한 방법의 효율성을 입증하기 위해 시뮬레이션을 수행하였으며, 처리율과 접속지연 관점에서 분석하였다.

• Communications for Statistical Applications and Methods
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• 제23권1호
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• pp.1-20
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• 2016

Causal inference methodologies have been developed for the past decade to estimate the unconfounded effect of an exposure under several key assumptions. These assumptions include, but are not limited to, the stable unit treatment value assumption, the strong ignorability of treatment assignment assumption, and the assumption that propensity scores be bounded away from zero and one (the positivity assumption). Of these assumptions, the first two have received much attention in the literature. Yet the positivity assumption has been recently discussed in only a few papers. Propensity scores of zero or one are indicative of deterministic exposure so that causal effects cannot be defined for these subjects. Therefore, these subjects need to be removed because no comparable comparison groups can be found for such subjects. In this paper, using currently available causal inference methods, we evaluate the effect of arbitrary cutoffs in the distribution of propensity scores and the impact of those decisions on bias and efficiency. We propose a tree-based method that performs well in terms of bias reduction when the definition of positivity is based on a single confounder. This tree-based method can be easily implemented using the statistical software program, R. R code for the studies is available online.

• 여성건강간호학회지
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• 제4권2호
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• pp.245-257
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• 1998

The characteristics of health behavior related pregnancy and childbirth have reflected on the cultural belief and value in the society. The efforts for women's health promotion through the current illumination of the traditional health care are the prompting assignment to be in nursing. The process of motherhood already progress before the motherhood actually. The functional state as the expectant mother can be the important predicting factor of the postpartum state, the quality of a married life. Motherhood was analyzed by Walker and Avant's method to clarify the concept 'to be a mother' using the various concepts like Koreans' Taekyo, transition to motherhood, maternal identity, maternal role attainment, maternal fetal attachment, and maternal fetal interaction. Upon the concept analysis, naturalness, responsibility, attachment, readiness, controllability were identified as the defining characteristics of motherhood. The antecedents of motherhood were consist of maternal affection, positive self esteem, pregnancy acceptance, fetus recognition and the consequences of motherhood were consist of positive maternal identity, maternal fetal attachment, confidence about the maternal role, the healthy mother and the healthy baby. The empirical referents of motherhood were consists of recognition of motherhood, expectation about motherhood, fetal recognition with ultrasonography and fetal movement, experience of unification between mother and fetus, expression of affection to the fetus, concern about fetal health, concern and practice about Taekyo, adaptation behavior about physical change and discomfort due to pregnancy. Therefore it is necessary to develop the instruction program of motherhood including the defining attributes identified in this study.

• 조명전기설비학회논문지
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• 제23권11호
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• pp.52-60
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• 2009

High reliability is essential for power transformers, and their fault causes are reportedly more related to mechanical causes than electrical ones. The transformer soundness judgment currently depends only on the electrical insulation characteristic and the chemical test of the insulation oil, so that there are few fundamental measures against the frequent mechanical damages and failures in transformers. The mechanical soundness judgment techniques are conducted through processes that include structural analysis and vibration resistance treatment during the manufacturing process of each manufacturer, but the vibration is not tested during the design, manufacturing, and operating processes since there are no detailed technical standards and procedures on the vibration problem, which are important in terms of maintenance. Therefore, in this study, vibration phenomena were measured from the 32 power transformers in operation in the substations under the Daejeon Power Transmission District Office of the Korean Electric Power Corporation (KEPCO). The vibration was measured at 24 sections ($6{\times}4$) on one side, and only the maximum values were selected from the measured vibration values. This was because the maximum vibration values more significantly affect the soundness of the transformer than the average vibration values. The vibration classes were given considering the maximum vibration based on ISO 10016-1 (2001).