• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1069-1074
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• 2022

IP mobility can be handled in different layers of the protocol. Mobile IP has been proposed to handle the mobility of Internet hosts in the network layer. Recently, a new method based on the SIGMA mobility architecture has been proposed to support mobility management with reduced packet loss and latency. The location management structure is not suitable for frequent mobile handover due to the high mobility of the user with this transport layer solution. In this paper, we propose a location management optimization method in a mobile communication network by applying hierarchical location management using MMPs(Mobility Management Points) for transport layer mobility management. Therefore, we propose an efficient hierarchical mobility management structure even between heterogeneous wireless networks using MMPs for the probability that a mobile terminal can change multiple location areas between two messages and calls. The proposed method shows reduction in location update cost and data retrieval cost using MMPs, and as opposed to mobility appearing in time intervals with the minimum cost required to reach 90% of the stabilized cost, the mobility location update search, location It was found that the message processing cost per area was reduced.

• 센서학회지
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• 제6권6호
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• pp.483-490
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• 1997

Thin film Si has been used in sensors, radiation detectors, and solar cells. The carrier mobility of thin film Si influences the device behavior through its frequency response or time response. Since poly-Si shows the higher mobility value, a-Si:H films on Mo substrate were subjected to various crystallization treatments. Consequently, we need to find an appropriate method in mobility measurement before and after the anneal treatment. This paper investigates the carrier mobility improvement with anneal treatments and summarizes the mobility measurement methods of the a-Si:H and poly-Si film. Various techniques were investigated for the mobility determination such as Hall mobility, HS, TOF, SCLC, TFT, and TCO method. We learned that TFT and TCO method are suitable for the mobility determination of a-Si:H and poly-Si film. The measured mobility was improved by $2{\sim}3$ orders after high temperature anneal above $700^{\circ}C$ and grain boundary passivation using an RF plasma rehydrogenation.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.852-857
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• 2017

In this paper, measurements of ion mobility were performed in oxygen at gas pressures of 44.52 - 101.19 kPa using the drift tube method. Over this pressure range, mobility values were within the limits of 1.796 to $3.821cm^2{\cdot}V^{-1}{\cdot}s^{-1}$ were determined and ion mobility shown to decrease non-linearly with increasing gas pressure towards a certain level of saturation. Ion mobility measured in air was lower than that measured in oxygen at the same gas pressure. Finally, a parameter correction method for calibrating the relationship between the ion mobility and gas pressure in oxygen was proposed.

• Journal of information and communication convergence engineering
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• 제17권2호
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• pp.97-104
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• 2019

Distributed mobility management (DMM) does not use a centralized device. Its mobility functions are distributed among routers; therefore, the mobility services are not limited to the performance and reliability of specific mobility management equipment. The DMM scheme has been studied as a partially distributed architecture, which distributes only a packet delivery domain in combination with the software defined network (SDN) technology that separates the packet delivery and control areas. Particularly, a separated control area is advantageous in introducing a new service, thereby optimizing the network by recognizing the entire network situation and taking an optimal decision. The SDN-based mobility management scheme is studied as a method to optimize the packet delivery path whenever a mobile node moves; however, it results in excessive signaling processing cost. To reduce the high signaling cost, we propose a hybrid distributed mobility management method and analyze its performance mathematically.

• 디지털융복합연구
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• 제10권3호
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• pp.265-271
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• 2012

본 논문에서는 무선 랜 방식을 적용한 서비스 로봇의 이동성을 위한 통신거리 성능평가 방법을 제안한다. 서비스 로봇은 서비스의 분류에 따라 모바일 통신 시스템의 기능을 갖추고 있고, ISM밴드(2.4GHz와 5.8GHz)의 무선랜(IEEE802.11a/b/g/n) 통신 방식을 선호하고 있다. 이러한 서비스 로봇의 이동성에 대한 무선 데이터 열화 성능을 평가하기 위해서 실질 필드 환경에서 거리감쇄 상관기법을 활용한 기준 벡터를 측정하여 제시하였다. 성능평가 방법은 기준 벡터의 Path Loss를 Azimuth 301W 장비에 대입하고, 시험 시료의 전송속도 및 송수신되는 처리량은 Chariot로 측정한다. 제안한 측정방법은 모바일 스마트 디바이스와 서비스 로봇의 이동성을 위한 무선 랜 통신거리 확보에 필요한 성능평가 방법이다. 또한 모바일 스마트 디바이스 업체들이 무선 랜 이동성 통신거리 성능평가를 위한 평가 방법으로 활용 할 수 있다.

• 한국전기전자재료학회논문지
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• 제11권6호
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• pp.423-427
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• 1998

In this paper the electron mobility in $Ga{1-X}In_xAs$alloy semiconductors is simulated by using the ensemble Monte Carlo method. The simulations for Ga\ulcornerIn\ulcornerAs with In mole fraction, doping concentration and temperature as parameters are performed. The electron mobility for alloys which perfectly orderd alloys without the alloy scattering mechanism are assumed, the results show that mobility in Ga\ulcornerIn\ulcornerAs is improved by 11%, 12% and 7% for 0.25, 0.53 and 0.75. In mole fractions, respectively, We reported the theoretical results of electron mobility in $Ga{1-X}In_xAs$alloys, so those will contribute to the research and development into materials for high-speed semiconductor devices.

• 전기전자학회논문지
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• 제16권2호
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• pp.81-85
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• 2012

본 논문에서는 macro-cell 위에 동일한 주파수를 쓰는 pico-cell이 overlay 되어 있는 환경에서, 움직이는 사용자에 대한 management 방법이 움직이는 사용자가 지원 받을 수 있는 data rate에 미치는 영향을 분석한다. 이러한 분석을 통해 mobility management 방식에 따른 움직이는 사용자가 지원받을 수 있는 data rate는 사용자와 pico-cell의 상대적 위치에 의존함을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.117.5-117
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• 2002

. Mobility analysis for overconstrained mechanisms is not clearly explained. . Aims at mobility analysis of overconstrained mechanisms . Representative screws is employed as a tool . A method to identifying the representative screw is introduced . Mobility analysis for several overconstrained parallel mechanisms and mobile robots

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.273-278
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• 2007

In the next generation wireless mobile network, various methods are studied to offer interworking and mobility between various radio networks. To offer these harmoniously, network adaptation methods based on IP is generalized, and specifications of host-based mobility method with Mobile IPv4 and Mobile IPv6 to offer IP's mobility are defined in IETF specially. However, it is insufficient to satisfy quality of service that should be offered in wireless mobile network environment. Alternatively studies about Network-Based Mobility of Proxy Mobile IPv4, Proxy Mobile IPv6 etc. are preceded. This paper presents optimum plan that can offer mobility in the next generation radio transfer communication network by comparing and analyzing IP mobility methods divided by Host-based Mobility and Network-based Mobility.

• 한국콘텐츠학회논문지
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• 제10권5호
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• pp.37-44
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• 2010

이동 중에 모바일 단말기를 통하여 IPTV 서비스를 제공하는 와이브로 모바일 IPTV에서 이동성(mobility)은 매우 중요한 요소이면서 보안에 있어서는 취약한 면을 가지고 있는 요소이다. 본 논문에서는 와이브로 모바일 IPTV의 안전한 서비스를 위하여 핸드오버 이외에 제한수신 시스템도 내부에 이동성을 보장하는 기술을 포함하고 있어야 함을 나타내었다. 모바일 IPTV 서비스 이용 중에 발생할 수 있는 보안 위협을 다운로드형 제한수신 시스템(DCAS)을 중심으로 분석하고, 이에 대한 대응 방법으로서 DCAS 호스트에 사용자 디바이스의 주소를 알리는 방법을 제안하였다. 제안 방법을 적용했을 때 사용자 인증 횟수가 감소하여 효율성이 향상됨을 보였다. 또, 한국정보통신기술협회에서 요구하고 있는 보안 요구 사항과의 비교를 통하여 제안 방법을 적용할 때 모바일 IPTV의 이동성이 보장될 수 있음을 보였다.