• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3335-3356
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• 2015

In this paper, we analyze the connectivity of cognitive radio ad-hoc networks in a log-normal shadow fading environment. Considering secondary user and primary user's locations and primary user's active state are randomly distributed according to a homogeneous Poisson process and taking into account the spectrum sensing efficiency of secondary user, we derive mathematical models to investigate the connectivity of cognitive radio ad-hoc networks in three aspects and compare with the connectivity of ad-hoc networks. First, from the viewpoint of a secondary user, we study the communication probability of that secondary user. Second, we examine the possibility that two secondary users can establish a direct communication link between them. Finally, we extend to the case of finding the probability that two arbitrary secondary users can communicate via multi-hop path. We verify the correctness of our analytical approach by comparing with simulations. The numerical results show that in cognitive radio ad-hoc networks, high fading variance helps to remarkably improve connectivity behavior in the same condition of secondary user's density and primary user's average active rate. Furthermore, the impact of shadowing on wireless connection probability dominates that of primary user's average active rate. Finally, the spectrum sensing efficiency of secondary user significantly impacts the connectivity features. The analysis in this paper provides an efficient way for system designers to characterize and optimize the connectivity of cognitive radio ad-hoc networks in practical wireless environment.

• 한국측량학회지
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• 제29권6호
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• pp.593-599
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• 2011

지리정보에 대한 사용자의 활용도가 높아지면서 더 새롭고 고품질인 지리정보 자료에 대한 요구 역시 함께 증가하고 있다. 새로운 콘텐츠를 제작하는데 있어 기 구축된 자료간의 융합을 통한 방법은 기존의 자료들이 가진 장점만을 취하여 새로운 지리정보 콘텐츠를 생성할 수 있다는 점에서 효율적이다. 그러나, 서로 다른 자료를 융합하면 위치편차와 형상불일치가 나타나는데 이는 이종의 자료가 가진 정보의 정확도는 그대로 유지한 채 자료 간 불일치되는 부분을 개선하는 합성 기술로 해결이 가능하다. 본 연구에서는 선행연구를 통해 위치편차가 최소화된 도로지도와 항공사진간에 형상불일치를 제거하는 것을 목적으로 하여 항공사진에서 도로 후보 영상을 생성한 후 이를 도로일 가능성으로 표현한 그래프를 제작하였다. 여기서 도로일 가능성이 높은 것만을 추출하여 합성 시 형상불일치를 제거할 수 있었다.

• 대한공간정보학회지
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• 제21권3호
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• pp.3-9
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• 2013

녹색성장에 대한 관심이 높아지면서 친환경 교통수단인 자전거의 중요성이 증대되고 있다. 그러나 이에 기반이 되는 자전거도로는 지형적 요소를 고려하지 않고 설계되고 있어 실제 많은 이용자가 자전거를 이용하는데 불편함을 겪고 있는 실정이다. 본 연구는 자전거 활용에 있어서 통학에서 경로선택을 할 때 지형적 요소를 고려한 최적 노선을 선택하는 경로기법을 제시한다. 이를 위해 최적경로의 연산에 있어서 경사도와 교차로를 고려한 식을 도출하였으며, 변형된 다익스트라 알고리즘(Dijkstra Algorithm)을 적용해 최적 노선을 선정하는 방법에 대하여 연구하였다. 분석결과, 통학용 자전거도로는 목적지까지 신속하게 이동하기 위해, 목적지까지의 이동거리보다는 최단시간에 의해 선정되어야한다. 따라서 노선을 선정할 때 횡단보도나 교차로에 의한 대기시간과 경사에 의한 속도증감을 고려한 최단시간 노선을 기준으로 해야 한다.

• 한국조리학회지
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• 제5권2호
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• pp.447-467
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• 1999

Most published work on product quality focuses on manufactured goods. The subject of service quality has received less attention. This distinction is important because some of the quality-improving strategies avaliable to manufacturers may be inappropriate for service firms. Services are performances, not objects. They are often produced in the presence of the customer, as in the cause of hotel restaurant services, quality occurs during service delivery, usually in an interaction between the customer and contact personnel of service firm. for this reason, service quality is highly dependent on the performance of employees, an organizational resource that cannot be controlled to the degree that components of tangible goods can be engineered. The study has begun as a basic study for customer satisfaction-oriented management in understanding the service quality of food & beverage products and through a systematic analysis of it. The major purpose of the study was to examine the relationship of the customer satisfaction and service quality in consideration of reliability, empathy, responsiveness, tangibility and assurance. An empirical research was conducted based on the previous theoretical studies. 286 customer at first class hotels in Seoul were selected as samples of this study. The time period of research was from February through March 1999, and answers were processed by SAS to yield frequency analysis, multivariate statistical analysis and regression analysis. The finding of the statistical treatment are frequencies, factor analysis, multiple regression analysis, path analysis. SERVQUAL method was used the service quality evaluation methods. After factor analysis, it was resulted to 3 factors. those were factor 1(assurance.empathy.responsiveness), factor 2(reliability), factor 3(tangibility). The findings of the statistical treatment are as follows. First, the attribute measurement of performance service quality was affected by customer satisfaction. Second, the attribute measurement of performance service qualify was affected by repurchase intention. Third, The attribute measurement of performance customer satisfaction was affected by repurchase intention. The result of study model was followed, service quality was affected repurchase intention than customer satisfaction. indirected effect through, service duality and customer satisfaction was affected repurchase intention.

• 한국조리학회지
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• 제18권4호
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• pp.118-132
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• 2012

본 연구에서는 조직성과에 근간을 이루는 조직몰입에 영향을 미치는 변수로 심리적 자본을 제안하여 그 역할을 규명하고 심리적 자본과 조직몰입과의 관계에서 직무만족의 매개역할을 규명함으로써 조직몰입을 높이기 위한 구체적인 방안을 모색하고자 하였다. 그 결과를 바탕으로 높은 이직률과 신규 사원 채용에 어려움을 겪고 있는 외식기업에 새로운 인적자원관리 방안을 제시하고자 하였다. 설문조사는 2012년 2월 1일부터 2월 29일까지 29일간 실시하였으며, 서울시내 프랜차이즈 및 직영 형태의 기업형 외식업체의 식음료 부문과 조리 부문 종사원을 대상하였다. 자료의 처리는 SPSS 15.0과 AMOS 7.0 통계패키지를 사용하여 빈도분석, 탐색적 요인분석, 신뢰도분석, 확인요인분석, 경로분석, 상관관계분석, 매개효과 분석을 사용하였다. 그 결과 심리적 자본요인 중에서 희망과 탄력성, 낙천성이 직무만족에 긍정적인 영향을 미치며, 직무만족은 희망과 탄력성, 낙천성 사이에서 강한 매개 효과가 있는 것으로 나타났다.

• 가정과삶의질연구
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• 제33권2호
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• pp.119-134
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• 2015

The purpose of the study is to explore how parenting attitudes, ego resilience, and care affects adolescents' adjustment to school so as to provide a necessary basic guideline needed to seek various intervention methods. To achieve this end, the study referred to the 2014 Annual Report of the Korean Children and Youth Panel Survey. By using both SPSS 19.0 and AMOS 19.0, the study yielded the following results. First, the study showed that parenting attitudes, ego resilience, care, and school adjustment all have a positive correlation. Second, by conducting path analysis in order to verify the mediating effect of ego resilience and care with regards to the relationship between parenting attitudes and school adjustment, the direct influence that parenting attitudes had on school adaptation was shown to be relevant. Third, adolescents' ego resilience and care have a partial mediating effect on the relationship between parenting attitudes and school adaptation. Therefore, together with intervention in actual school settings, assessing various factors that would aid the recovery of adolescents' characters and pursuing a positive reinforcement of character by finding protective factors would enable this study to be used as a basic guideline that would prevent adolescents' maladjustment to school and social deviance as well as aid the growth of their characters.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.833-837
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• 2010

본 연구는 최소 압력 모사로 엔진 배기가스를 배출시키기 위한 최적 이젝터 크기를 결정하기 위한 것을 목적으로 한다. 실험 챔버로 유입되는 2차 냉각 공기는 유량제어 밸브들과 진공펌프가 장착된 배출구를 통해 엔진배기가스는 분리되어 배출된다. 기존 고도시험 장치와 달리, 본 연구에 제안한 형상은 기존 이젝터의 압력 회복을 개선한 좀 더 작은 포획 면적을 가진 배기 이젝트를 사용하면 가스에 스텔링 챔버로 부터 20% 냉각 공기를 부가하여 배출시키도록 크기가 정해진다. 제안된 형상은 벨마우스 이젝터와 엔진배기 출구의 면적비가 이론적으로 약 1.2를 갖는다. 제안된 형상의 혼합 공기 모사결과에 따르면 큰 에너지는 기존 시스템 비해 좀 더 개선된 압력 회복과 감소된 전력 소모를 같음을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권9호
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• pp.824-829
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• 2016

최근 크루즈 선박과 같이 선박의 대형화, 복합화가 진행됨에 따라 선박사고 시 인명피해가 증가하여, 선박 재난시 승객 안전을 확보하기 위한 기술의 필요성이 증가하고 있다. 현재까지는, 선박 내 사고 상황 시 안내방송 및 화재경보 비상벨, 비상유도등과 같이 현재 위치에서 안전한 곳으로 대피하라는 단순한 신호만 줄 뿐 적절한 탈출 경로를 선택함에 있어서 도움을 주지는 못한다. 이러한 문제를 해결하기 위한 여러 대피유도 방안이 제안되어 왔지만 다양한 위험요소와 그에 대한 특성에 대한 고려가 부족하여 실제 시스템에 적용하는 데 어려움이 있다. 따라서 본 논문에서는 다양한 위험요소와 해당 특성을 고려할 수 있는 $A^*$ 알고리즘 기반의 대피유도 시스템을 제안한다. 가상 구조물 및 선박 내 재난 상황을 가정한 컴퓨터 시뮬레이션을 통해 제안된 방식의 성능을 검증하였다.

• 가정과삶의질연구
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• 제23권3호
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• pp.197-215
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• 2005

The purpose of this study is to examine how the causal relationships between independent variables, marital communication decision making participation and family life satisfaction of elderly in couple household. The survey was conducted from May 26 to July 21, 2003. Total 394(male: 186, female: 208) samples were used for the analysis. Using SPSS/PC WIN program, data were analyzed by frequencies, percentages, mean, standard deviation, Cronbach'a, Pearson's correlation, t-test, and multiple regression. The major findings were as follows: 1) The findings showed that there were high level of the communication between the elderly males and females. In the decision making participation the finding showed that both elderly males and females generally made joint decisions with no gender differences. The elderly males and females reported overall family life satisfaction; and the elderly males were more likely satisfied with their family lives than the elderly females. 2) The path analysis on family life satisfaction presented that several variables had direct/indirect effects on family life satisfaction through communication and decision making participation. Among the moderate variables, communication agreement and communication openness had significant effects on family life satisfaction. Specifically, the elderly men were more likely satisfied when they participated in decision making on leisure: the elderly women were more likely satisfied when they participated in decision making on family life.

• 한국BIM학회 논문집
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• 제6권3호
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• pp.34-41
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• 2016

The previous studies argue that using the semantic properties of BIM objects is efficient for simulating the behaviors of autonomous, computer agents, called virtual-users, but such assumption is not proven via evidence-based research approaches. Hence, this present study aims to investigate the empirical effects of a human behavior simulation model equipped the semantics of spaces on the architecture-major students' operation and understanding of the simulation system, compared to a typical path-finding model. To achieve the aim, this study analyzed the survey and interview data, collected in the authentic design projects. The analysis indicates that (1) using a simulation model equipped the semantics of spaces helps the students' operation of the simulation, and (2) it also aids understanding the relationship between the variables of spaces and virtual-users (${\alpha}=0.74$). In addition, the qualitative data inform that the advantages of the simulation model that computes the semantics of spaces stem in the automatic behavioral changes of massive numbers of virtual-users, and efficient detection and activation on the what-if situations. The analysis also reveals that the simulation model has shortcomings in orchestrating the complex data structure between the semantics properties of spaces and virtual-users under multi-sequential scenarios. The results of this study contribute to develop a future design system combining BIM with human behavior simulation.