• 한국ITS학회 논문지
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• 제20권2호
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• pp.58-71
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• 2021

전 세계적으로 고령인구가 급증하고 이에 따라 이동에 불편을 겪는 교통약자의 수도 증가하고 있다. 이러한 추세에 따라 국내에서는 이동편의시설 설치 확대 등 교통약자에 대한 양질의 대중교통 서비스 제공을 위해 다양한 정책을 시행 중이다. 기존 대중교통 이동편의시설 설치는 역사의 면적, 층수, 시설 미확보역 등의 양적인 측면을 기준으로 우선적 확대·설치되고 있다. 하지만 양적 기준 보다는 실제 이용자 기준의 설치 필요 지역에 이동편의시설을 확보하는 것이 교통약자의 이동편의 증진에 더 효과적일 것으로 사료된다. 본 연구에서는 이용자 기반의 교통카드 빅데이터 분석을 통해 교통약자의 환승취약지점을 도출하고자 했다. 스마트카드 거래내역 데이터를 가공하여 환승통행데이터를 구축하고 이용자별 환승통행패턴 분석 및 환승통행시간 차이가 큰 경로를 기준으로 환승취약지점을 도출했다. 분석 결과 일반 이용자보다 교통약자의 환승시간이 오래 걸리는 것으로 나타났다. 일반과 교통약자의 환승통행시간 차이와 시설물 개수와의 상관관계는 미약한 것으로 나타났는데 현장 조사 결과 환승통행시간 차이는 시설물의 단순 개수보다는 해당 환승최단경로 내 이동편의시설의 부재로 인해 발생하는 것으로 나타났다. 향후 교통약자를 위한 이동편의시설 확대 시 실질적 이용자 기반 데이터 분석을 통한 환승취약지점을 기준으로 우선적 시설 확보 시 교통약자의 이동편의가 보다 더 향상될 것으로 사료된다.

• 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.

• Journal of Communications and Networks
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• 제6권4호
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• pp.331-342
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• 2004

We study the problem of controlling data overhead of mesh-based multicast ad hoc routing protocols by adaptively adding redundancy to the minimal data overhead multicast mesh as required by the network conditions. We show that the computation of the minimal data overhead multicast mesh is NP-complete, and we propose an heuristic approximation algorithm inspired on epidemic algorithms. In addition, we propose a mobility-aware and adaptive mesh construction algorithm based on a probabilistic path selection being able to adapt the reliability of the multicast mesh to the mobility of the network. Our simulation results show that the proposed approach, when implemented into ODMRP, is able to offer similar performance results and a lower average latency while reducing data overhead between 25 to 50% compared to the original ODMRP.

• Journal of Periodontal and Implant Science
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• 제33권1호
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• pp.103-111
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• 2003

Tooth mobility is an important part of a periodontal examination and represents a function of the persisting height of the alveolar bone and the width of the periodontal ligament. The purpose of this study was to evaluate the changes of the tooth mobility over 4 week-period following surgical therapy on the periodontal disease. Thirty five patients presenting with moderate periodontal pockets were selected and tooth mobility was measured at weekly intervals using Periotest (Siemens Co., Germany) beginning at the pre-operation examination and ending four weeks following the modified Widman Flap. All data were statistically analyzed using the one-way ANOVA test. The results were obtained as follows; 1. All teeth exhibited the greatest change in mobility at 1 week post-op, mobility generally decreasing with time. 2. Comparison of the weekly tooth mobility data regarding the 1st premolars showed significant differences only between weeks 1 (9.94) and 4 (6.14) (p<0.05). 3. Comparison of the weekly tooth mobility data regarding the 1st molar showed significant changes in the intervals between pre-op (6.49) and week 1 (11.22), pre-op and week 2 (9.37), weeks 1 and 3 (7.65), weeks 1 and 4 (5.62), and weeks 2 and 4 (p<0.05). 4. Comparison of the weekly tooth mobility data regarding the 2nd premolar and 2nd molar showed significant differences between pre-op (6.91, 8.60) and week 1 (11.02, 12.62), weeks 1 and 3 (8.00, 8.05), weeks 3 ad 4 (6.22, 6.71), and weeks 2 (9.34, 11.01) and 4 (p<0.05).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.872-885
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• 2015

The rapid increase of smart mobile devices and mobile applications has led to explosive growth of data traffic in cellular network. Offloading data traffic becomes one of the most urgent technical problems. Recent work has proposed to exploit opportunistic communications to offload cellular traffic for mobile data dissemination services, especially for accepting large delayed data. The basic idea is to deliver the data to only part of subscribers (called target-nodes) via the cellular network, and allow target-nodes to disseminate the data through opportunistic communications. Human mobility shows temporal and spatial characteristics and predictability, which can be used as effective guidance efficient opportunistic communication. Therefore, based on the regularity of human mobility we propose NodeRank algorithm which uses the encounter characteristics between nodes to choose target nodes. Different from the existing work which only using encounter frequency, NodeRank algorithm combined the contact time and inter-contact time meanwhile to ensure integrity and availability of message delivery. The simulation results based on real-world mobility traces show the performance advantages of NodeRank in offloading efficiency and network redundant copies.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권3호
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• pp.276-280
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• 2008

무선 센서 망에서 이동성 지원을 위한 많은 데이타 전달 프로토콜들이 군인들이나 구조원과 같은 싱크의 이동 궤적이 랜덤하다는 가정 아래서 디자인되어왔다. 하지만, 많은 응용에서, 예를 들면 전쟁 지역에서 작전 상황 중의 군인의 이동 궤적과 같은, 싱크의 이동성은 미리 결정될 수 있다. 본 논문에서, 우리는 싱크들의 예측 가능한 이동성을 고려하여 소스 노드로부터 이동하는 싱크까지 데이타를 우회 없이 직행으로 전달할 수 있는 싱크의 예측 가능한 이동성 기반 데이타 전달 프로토콜을 제안한다. 또한, 우리는 기존의 랜덤한 이동성 기반의 데이타 전달 프로토콜들과의 성능 비교를 통해 예측 가능한 이동성 기반 데이타 전달 프로토콜의 향상성을 증명한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4054-4071
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• 2015

Named-Data Networking (NDN) is one of the promising approaches for the Future Internet to cope with the explosion and current usage pattern of Internet traffic. Content provider mobility in the NDN allows users to receive real-time traffic when the content providers are on the move. However, the current solutions for managing these mobile content providers suffer several issues such as long handover latency, high cost, and non-optimal routing path. In this paper, we survey main approaches for provider mobility in NDN and propose an optimal scheme to support the mobile content providers in the large-scale NDN domain. Our scheme predicts the movement of the provider and uses state information in the NDN forwarding plane to set up an optimal new routing path for mobile providers. By numerical analysis, our approach provides NDN users with better service access delay and lower total handover cost compared with the current solutions.

• 대한가정학회지
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• 제47권6호
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• pp.79-90
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• 2009

The purpose of this study was to improve the understanding of housing experiences of the married women in Korean sociocultural context and to explore their housing mobility. The grounded theory was adopted in this qualitative study. Data were collected through in-depth interviews with the seventeen married women. The major categories found in the data are 1) the inducement of housing mobility, 2) social constraint and opportunity, 3) the strategy and resource of housing mobility, 4) the intervening conditions, and 5) self-evaluation of their own housing life history. People construct their housing life history toward home ownership. There are a few factors to induce housing mobility, and social constraints and opportunity have an effect on obtaining home ownership. They utilize the diverse strategy and resource to solve their housing matter. Through interview, it is founded that they evaluate their housing career in the light of their life through interview.

• 한국IT서비스학회지
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• 제15권3호
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• pp.211-221
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• 2016

The human spatial mobility information is in high demand in various businesses; however, there are only few studies on human mobility because spatio-temporal data is insufficient and difficult to collect. Now with the spread of smartphones and the advent of social networking services, the spatio-temporal data began to occur on a large scale, and the data is available to the public. In this work, we compared the movement behavior of residents and tourists by using geo-tagged tweets which contain location information. We chose Seoul to be the target area for analysis. Various creative concepts and analytical methods are used: grid map concept, cells visited concept, reverse geocoding concept, average activity index, spatial mobility index, and determination of residents and visitors based on the number of days in residence. Conducting a series of analysis, we found significant differences of the movement behavior between local residents and tourists. We also discovered differences in visiting activity according to residential countries and used applications. We expect that findings of this research can provide useful information on tourist development and urban development.

• ETRI Journal
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• 제45권4호
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• pp.603-614
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• 2023

Advancements in remote medical technologies and smart devices have led to expectations of contactless rehabilitation. Conventionally, rehabilitation requires clinicians to perform routine muscle function assessments with patients. However, assessment results are difficult to cross-reference owing to the lack of a gold standard. Thus, the application of remote smart rehabilitation systems is significantly hindered. This study analyzes the factors affecting the real-time evaluation of muscle function based on biometric sensor data so that we can provide a basis for a remote system. We acquired real clinical stroke patient data to identify the meaningful features associated with normal and abnormal musculature. We provide a system based on these emerging features that assesses muscle functionality in real time via streamed biometric signal data. A system view based on the amount of data, data processing speed, and feature proportions is provided to support the production of a rudimentary remote smart rehabilitation system.