• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권3호
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• pp.141-148
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• 2017

인간의 위치 이동 데이터를 모바일 기기에서 수집한 위치 정보를 이용해 얻을 수 있게 되면서, 위치 정보를 어떻게 이용할 수 있는지 그 활용 방안이 중요시 되고 있다. 이 연구에 앞서 위치 정보에 포함된 위치 정보와 시간 정보를 이용한 개인 이동성 모델 도출 연구가 선행되었다. 이동성 모델의 개념을 집단으로 확장하여 특정 집단에 속한 사람들의 개인 이동성 모델을 이용한 집단 이동성 모델을 도출하는 방법에 대해서 연구했고, 두 명의 개인 이동성 모델을 이용한 집단 이동성 모델과 그 모델을 표현하는 Markov 모델을 생성할 수 있었다. 본 논문에서는 세명 이상의 개별 이동 모델을 포함하는 사람의 이동성 모델을 생성하고 집단 모델 내 군집간의 확률 기반 Markov 모델을 도출하는 방법에 대해 소개한다. 또한 GPGPU 기법을 통해 생성 시간을 줄이는 기법을 이용하여 실용화를 고려하였다.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.53-59
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• 2007

This paper proposes a new group mobility model for wireless communication. The mobility model considers the psychological and sociological behavior of each node and the perception of other nodes for describing interactions among a set of nodes. The model assumes no permanent membership of a group, capable of capturing natural behaviors as fork and join. It emulates a cooperative movement pattern observed in mobile ad hoc networks of military operation and campus, in which a set of mobile stations accomplish a cooperative motion affected by the individual behavior as well as a group behavior. The model also employs a physic model to avoid a sudden stopping and a sharping turning.

• 한국정보전자통신기술학회논문지
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• 제3권3호
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• pp.62-72
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• 2010

As the applications for Mobile Ad-hoc NETworks (MANETs) have varied, performance analysis has become one of the main research areas. They commonly offer only simple radio propagation models that neglect obstacles of a propagation environment. The radio wave propagation model has a strong impact on the results of the simulation run. In this paper we present the new experimental results of the impacts of the various propagation models on MANETs' performance. Intensive simulations have been presented using the group mobility which models typical ad-hoc situations such as military movements or disaster recovery activities under the supervision of a group leader. Comparisons of conventional simple models with more complicated models, i.e., shadowing, Raleigh, and Ricean models, show that, in spite of the models' popularity, the free space and two-ray ground models are too optimistic in describing real ad-hoc group mobility situations.

• Journal of Information Processing Systems
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• 제3권1호
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• pp.1-7
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• 2007

In mobile ad hoc networks, an application scenario requires mostly collaborative mobility behavior. The key problem of those applications is scalability with regard to the number of multicast members as well as the number of the multicast group. To enhance scalability with group mobility, we have proposed a multicast protocol based on a new framework for hierarchical multicasting that is suitable for the group mobility model in MANET. The key design goal of this protocol is to solve the problem of reflecting the node's mobility in the overlay multicast tree, the efficient data delivery within the sub-group with group mobility support, and the scalability problem for the large multicast group size. The results obtained through simulations show that our approach supports scalability and efficient data transmission utilizing the characteristic of group mobility.

• International Journal of Advanced Culture Technology
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• 제1권2호
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• pp.7-12
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• 2013

Mobility management is an important issue in Mobile Ad Hoc Networks (MANETs) because location information of mobile nodes is frequently changed and it aggravates the performance in MANETs drastically. In this paper, we propose a fuzzy logic based mobility management scheme using group quorum system by considering the mobile nodes' locality in order to manage location information of mobile nodes in MANETs efficiently. The proposed scheme selects mobility databases adaptively from group quorum system by considering the degree of locality of a mobile node. The performance of the proposed scheme is evaluated by an analytical model and compared with that of existing mobility management scheme.

• 유통과학연구
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• 제18권1호
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• pp.107-121
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• 2020

Purpose: Shared mobility services are the most notable in the shared economy; however, they have yet to be activated in Korea due to various regulations and conflicts amongst stakeholders. Nevertheless, shared mobility has become an irresistible trend of the times, as it can cause a great deal of economic and environmental benefits. In this vein, the purpose of this study is to contribute to the revitalization of shared mobility services in Korea and to provide service providers with implications for developing consumer-oriented marketing strategies. Research design, data and methodology: Based on the reasons that the users do not use shared mobility service, the factors influencing the behaviors of shared mobility users are structured and analyzed in a reliable, technical and procedural manner. To this end, the theory of reasoned action (TRA) of Ajzen and Fisbbein, the initial trust model (ITM), task technology fit (TTF) and switching cost (SC) are adopted. A total of 202 questionnaires were collected from the respondents who were aware of shared mobility. Then statistical processing of the collected data used SmartPLS(v.3.2.8), a PLS-SEM (Partial Least Squares Structural Equation Modeling) analysis program. The steps of the analysis are as follows. First, a PLS-Algorithm analysis was performed to evaluate the measurement model, and a Bootstraping and Blindfolding analysis was performed to evaluate the structural model and verify the hypotheses. Second, a multi-group analysis (PLS-MGA) was conducted to further analyze the differences depending on whether or not users experienced shared mobility service. Results: The results showed that initial trusts model (ITM) and task technology fit (TTF) have positive effects on users' behaviors through the mediation of the intention to use. As opposed to the assumption, switching costs did not have negative moderating effects in relation to the intention to use and users' behaviors. The influence of IT self-efficacy was significant, depending on the prior experience to use shared mobility services. Conclusions: This study will contribute to the revitalization of domestic shared mobility services and the formulation of service providers' marketing strategies. In future studies, there is a need to explore, reconstruct, and validate factors other than the impact factors of the shared mobility services used in this research model.

• 전자공학회논문지CI
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• 제45권6호
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• pp.52-59
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• 2008

기존의 ad-hoc 라우팅 프로토콜 성능분석은 ad-hoc을 구성하는 모든 노드들이 독립 이동하는 모델을 중심으로 주로 수행되었다. 그러나 실제 상황에서는 노드가 임의로 독립 이동을 하기보다는 단일 그룹 또는 몇 개의 그룹을 구성하여 이동하며 각 그룹에 리더가 존재하는 경우가 자주 발생하게 된다. 본 논문은 그룹의 리더가 존재하는 그룹 이동 환경에서의 ad-hoc 라우팅 프로토콜의 성능분석을 수행하여 새로운 결과를 제시하였다. 군 전술 이동 망 등에 적합한 그룹 이동 모델인 RPGM 환경에서의 테이블 기반 DSDV 프로토콜과 요구 기반 AODV와 DSR 프로토콜 성능을 비교 분석 하였다. 단일 그룰 외에 다수 그룹의 이동도 함께 연구 제시하여 그룹 이동에 따른 특성 분석을 보다 포괄적으로 수행하고자 하였다. 단일 그룹 환경에서의 일반적인 성능특성은 노드 그룹 이동의 환경에서도 노드 독립 이동과 거의 유사함을 보였다. 그러나 독립이동의 경우 pause time이 증가함에 따라 높은 전송률을 보인 반면, 그룹이동 환경에서는 변함이 거의 없었다. 또한 연결 비율을 증가시키는 경우 기존 독립 이동시에는 전송지연시간이 일정하게 유지되나, 다수 그룹 이동의 경우 요구 기반 프로토콜 사용 시 감소하였다.

• 한국조명전기설비학회지:조명전기설비
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• 제2권2호
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• pp.55-58
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• 1988

관벽온도에 따른 형광램프 양광주 내의 전자이동도 변화를 계산하였다. 전자분포 함수는 2 Electron Group Model을 사용하였다. 또한 이를 검증하기 위하여, 38mm 20W 형광램프 양광주 내의 전자이동도를 관벽온도를 변화시키면서 측정하였다. 측정방법으로는 양광주 내의 전계를 구하기 위하여 양극 및 음극 강하전압의 합을 15V로 가정하였으며 2중 슬릿을 사용하여 양광주의 길이를 측정하였다. 관벽온도를 $10-18^{\circ}C$로 변화시키며 계산하고 측정한 결과를 표시하였다.

• 대한간호학회지
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• 제31권5호
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• pp.818-834
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• 2001

This study aims at confirming exercise effects on obesity, mobility, self-efficacy, process of change, and decisional component by stage based exercise motivational intervention program for the elderly. The stage based exercise intervention program was constructed based on Transtheoretical Model. Methods: The design of this study is nonequivalent control group with repeated measuring by quasi-experimental study. The subjects of this study, composing of experimental group of 32 and control group of 28 were selected at one institution for the aged in Seoul. Results: 1) The body fat (weight, BMI and circumference of waist), of the intervention group was significantly decreased than the control group. 2) The mobility of the intervention group was not significantly increased than control group. 3) The self-efficacy, Pros, Process of Change for exercise of the intervention group was not significantly increased than the control group. 4) The Cons for exercise of intervention group was not significantly decreased than the control group. Conclusion: The above result have informed us that a stage-based exercise motivational intervention program for the elderly has the effect of decreasing old persons' body fat and has value as an effective means of nursing for the elderly.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.637-658
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• 2015

The development of multimedia applications has followed the development of high-speed networks. By improving the performance of mobile devices, it is possible to provide high-transfer-speed broadband and seamless mobile multicasting services between indoor and outdoor environments. Multicasting services support efficient group communications. However, mobile multicasting services have two constraints: tunnel convergence and handoff latency. In order to solve these problems, many protocols and handoff methods have been studied. In this paper, we propose inter local mobility anchor (inter-LMA) optimized handoff model for mobile multicasting services in proxy mobility IPv6 based (PMIPv6-based) networks. The proposed model removes the tunnel convergence issue and reduces the router processing costs. Further, it the proposed model allows for the execution of fast handoff operations with adaptive transmission mechanisms. In addition, the proposed scheme exhibits low packet delivery costs and handoff latency in comparison with existing schemes and ensures fast handoff when moving the inter-LMA domain.