• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1590-1593
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• 2002

We propose a dynamic location management scheme and named it Virtual Dynamic Location Area(VDLA) scheme. It allocates LA on the basis of terminal mobility, VDLA consists of two phases: VLA allocation and final LA selection phases. In the first phase it allocates primary and secondary VLAs to the terminal. In the second phase the terminal selects one of them using LA selection criterion. Cost analysis of the proposed scheme is peformed and its location management cost is compared with those of FLA and DBLA.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.47-49
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• 1988

This paper discusses dynamic properties of bubble garnet thin films. The dynamic properties considered are Gilbert damping parameters, saturation velocity, and wall mobility. The parameters are evaluated to facilitate the search for desirable garnet thin film compositions. Given bubble diameter and Q-value, the computer prints out all compositions which meet the desired requirements. The computer model determines magnetization, anisotropy, damping, velocity, mobility among others from the film compositions. The computer modeling program is described by an algorithm detailing its operation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3568-3584
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• 2016

In mobile opportunistic networks (MONs), human-carried mobile devices such as PDAs and smartphones, with the capability of short range wireless communications, could form various intermittent contacts due to the mobility of humans, and then could use the contact opportunity to communicate with each other. The dynamic changes of the network topology are closely related to the human mobility patterns. In this paper, we propose a social motivation-aware mobility model for MONs, which explains the basic laws of human mobility from the psychological point of view. We analyze and model social motivations of human mobility mainly in terms of expectancy value theory and affiliation motivation. Furthermore, we introduce a new concept of geographic functional cells, which not only incorporates the influence of geographical constraints on human mobility but also simplifies the complicated configuration of simulation areas. Lastly, we validate our model by simulating three real scenarios and comparing it with reality traces and other synthetic traces. The simulation results show that our model has a better match in the performance evaluation when applying social-based forwarding protocols like BUBBULE.

• 대한인간공학회지
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• 제21권2호
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• pp.35-46
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• 2002

This study was performed to determine the voluntary range of joint mobility for middle-aged Korean adults. One hundred and eighty-eight subjects(99 males and 89 females) at the age range of 40 to 60 participated for this study. Thirty body movements at various joints were conducted to measure the range of joint mobility. Subjects were grouped by Rohrer's into four based on 25th percentile. The data were analyzed to see the differences of range of joint mobility between sexes and Rohrer's index groups. The results of this study and previous studies were compared to see the differences of range of joint mobility due to the aging. Results of this study indicate that females are generally more flexible than males. Significant differences were found to exist in fourteen movement between sexes and in ten movements, females have larger range of joint mobility than males. There were no significant differences in range of joint mobility may have a tendency to decrease with ages. The results of this study provide important information in dynamic dimensions for middle-aged Korean and can be used to design the various and work places for the middle-aged.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3018-3040
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• 2018

The mobility model is one of the most important factors that impacts the evaluation of any transportation vehicular networking protocols via simulations. However, to obtain a realistic mobility model in the dynamic urban environment is a very challenging task. Several studies extract mobility models from large-scale real data sets (mostly taxi GPS data) in recent years, but they do not consider the statuses of taxi, which is an important factor affected taxi's mobility. In this paper, we discover three simple observations related to the taxi statuses via mining of real taxi trajectories: (1) the behavior of taxi will be influenced by the statuses, (2) the macroscopic movement is related with different geographic features in corresponding status, and (3) the taxi load/drop events are varied with time period. Based on these three observations, a novel taxi mobility model (T-START) is proposed with respect to taxi statuses, geographic region and time period. The simulation results illustrate that proposed mobility model has a good approximation with reality in trajectory samples and distribution of nodes in four typical time periods.

• 한국멀티미디어학회논문지
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• 제11권4호
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• pp.544-553
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• 2008

통상적인 센서 네트워크는 센서노드로부터 고정된 정보를 수집하는 일괄적인 방식을 사용한다. 하지만 이러한 방식은 헬스케어 환경에서 주요 센싱대상인 사람의 상태와 위치변화, 주변 환경의 변화에 능동적으로 대처하기 어렵다. 헬스케어 환경을 지원하기 위해서는 사람의 상태와 주변상황의 변화에 따른 특정정보를 제공해주어야 한다. 또한 사람의 이동에 따른 네트워크 타입의 변화에 대처하여야 한다. 본 논문에서는 대표적인 다중 에이전트 미들웨어인 Agilla 모델과 주변노드간의 클러스터를 구성함으로써 네트워크의 효율성을 보장하는 LEACH 프로토콜에 대해 분석한다. 이 분석 결과를 기반으로 기존 LEACH 프로토콜의 취약점인 노드 이동성을 보장하는 LEACH_Mobile 프로토콜을 제안한다. 또한 노드의 동적 기능변경을 지원하는 Mobility Agent Middleware와 LEACH_Mobile 라우팅 모듈을 구성요소로 이동노드의 동적 기능변경을 지원하는 Mobility Agent 모듈을 설계한다. 그리고 LEACH_Mobile 프로토콜의 시뮬레이션 결과를 통해 네트워크의 데이터 전송 성공률에 대한 성능 향상을 보여준다.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권4호
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• pp.237-248
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• 2015

"Dynamic stabilization" systems have been developed in recent years to treat degenerative disorders of the spinal column. In contrast to arthrodesis (fusion), the aim here is to conserve intervertebral mobility to maximize comfort. When developing innovative concepts, many mechanical tests need to be carried out in order to validate the different technological solutions. The present study focuses on the B Dyn$^{(R)}$ "dynamic stabilization" device (S14$^{(R)}$ Implants, Pessac, France), the aim being to optimize the choice of polymer material used for one of the implant's components. The device allows mobility but also limit the range of movement. The stiffness of the ring remains a key design factor, which has to be optimized. Phase one consisted of static tests on the implant, as a result of which a polyurethane (PU) was selected, material no.2 of the five elastomers tested. In phase two, dynamic tests were carried out. The fatigue resistance of the B Dyn$^{(R)}$ system was tested over five million cycles with the properties of the polymer elements being measured using dynamic mechanical analysis (DMA) after every million cycles. This analysis demonstrated changes in stiffness and in the damping factor which guided the choice of elastomer for the B Dyn$^{(R)}$ implant.

• 한국통신학회논문지
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• 제31권12B호
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• pp.1068-1075
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• 2006

주파수 자원 가치는 무선통신의 발전과 함께 더욱 커지고 있다. 하지만 앞으로 정보화 사회에서는 주파수 자원의 수요가 공급에 비하여 매우 많기 때문에 주파수 부족 현상이 심각하게 대두된다. 따라서 사용되지 않고 있는 주파수 자원을 효율적으로 이용하기 위한 기술로서 최근 각광을 받고 있는 Cognitive Radio 기술이 필요한 시점이다. 본 논문에서는 CR 기반의IEEE 802.22 WRAN 환경에서 효율적인 Dynamic Spectrum Allocation 기법을 제안한다. Spectrum을 좀 더 효율적으로 공유하기 위해 Variable bandwidth, Mobility의 변수를 적용한 Dynamic Spectrum Allocation 기법을 제시하고 시뮬레이션 결과들을 통해 이를 검증하였다.

• 한국통신학회논문지
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• 제31권6B호
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• pp.544-550
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• 2006

차세대 무선/이동 네트워크는 IP 기반 구조로 진화하고 있다. 차세대 IP 기반의 네트워크에서 효율적인 이동성 관리는 필수적이다. 최근에 Internet Engineering Task Force(IETF)에서 효율적인 이동성 관리를 위해 Hierarchical Mobile IPv6(HMIPv6)을 제안하였다. HMIPV6는 Mobile Anchor Point(MAP)영역 안에 지역 등록을 통하여 상당히 시그널링을 줄일 수 있고 핸드오프 지연시간도 줄이면서 MIPv6의 성능향상을 가져왔다. 그러나 단일 MAP에 집중적인 부하가 발생하는 문제점을 가지고 있다. 또한 HMIPv6는 idle 상태에서도 이동노드의 불필요한 위치 등록으로 인하여 시그널링 오버헤드가 발생한다. 따라서 이동노드의 이동성 및 트래픽을 고려하여 동적으로 최적의 MAP 영역을 구성하고, IP 페이징 기법을 통하여 불필요한 위치 등록에 따른 시그널링을 줄이기 위한 페이징 기법을 제안한다. 본 논문에서는 평균적인 위치 등록비용과 패킷 전달비용의 수학적인 모델을 수립하고 성능을 평가한다. 결론적으로, 기존 기법에 비하여 제안된 기법이 보다 효율적임을 보여주고 있다.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 1995년도 Symposium and Workshop
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• pp.9-13
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• 1995

1. The static restraints are improtant in maintaining balance between shoulder mobility and stability. But the shoulder musculature plays the vital role in moving the joint and providing stability. 2. Study of the dynamic restraints continues and study of the combined effect of the static and dynamic restraints is demanded.