• International journal of advanced smart convergence
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• v.8 no.2
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• pp.39-46
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• 2019

Human mobility estimation plays a key factor in a lot of promising applications including location-based recommendation systems, urban planning, and disease outbreak control. We study the human mobility estimation problem in the case where recent locations of a person-of-interest are unknown. Since matrix decomposition is used to perform latent semantic analysis of multi-dimensional data, we propose a human location estimation algorithm based on matrix factorization to reconstruct the human movement patterns through the use of information of persons with correlated movements. Specifically, the optimization problem which minimizes the difference between the reconstructed and actual movement data is first formulated. Then, the gradient descent algorithm is applied to adjust parameters which contribute to reconstructed mobility data. The experiment results show that the proposed framework can be used for the prediction of human location and achieves higher predictive accuracy than a baseline model.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.617-620
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• 2011

본 논문은 Inter-Local Mobility Anchor 환경에서의 경로 최적화 기법을 Proxy Mobile IPv6 환경에서 캐쉬 정보를 활용하여 삼각 라우팅 문제를 해결하기 위해 경로 최적화 수행 시 빠른 처리 속도와 안정성을 가지는 방법에 대해 연구하였다. 기존의 경로 최적화 방법 중 inter-Local Mobility Anchor 환경에서 Liebsch의 방법은 모든 경우를 확인하기에 어떤 상황에서도 동일한 시그널링 코스트가 사용되지만 경로 최적화를 위한 프록시 바인딩의 시그널링 코스트가 많고, Dutta의 방법은 경로 최적화를 위한 프록시 바인딩의 시그널링 코스트는 효과적으로 감소시켰으나 Mobile Access Gateway 사이의 프록시 바인딩 과정이 없음으로 인하여 발생할 수 있는 문제점을 간과하였다. 본 논문에서는 Inter-Local Mobility Anchor 환경에서도 시그널링 비용은 증가시키지 않으면서 Local Mobility Anchor와 Mobile Access Gateway로부터 메시지를 받을 경우 응답 메시지를 전송하여 신뢰성을 향상시킨 경로 최적화 방법을 캐쉬 정보를 활용하는 방안에 관하여 연구하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.81-84
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• 2004

Required characteristics of poly-Si TFT's are investigated for the implementation of analog circuits to be integrated on System-on-Glass (SoG). Matching requirements on resistor values, threshold voltage and mobility of poly-Si TFT's are derived as a function of the resolution of display system. Effective mobility of poly-Si TFT's required for the realization of source driver is analyzed for various panel sizes.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.299-304
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• 2003

We discuss several key technologies of liquid crystal displays (LCDs) that share common features of all organic displays (AODs). An overview of the morphological effects associated with molecular ordering at interfaces on the Crystallinity and the carrier mobility in organic thin film transistors (OTFTs) is given from the viewpoint of the alignment mechanism for LCDs. Recent progress of improving the carrier mobility in the OTFTs is also reviewed.

• Journal of Information Display
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• v.5 no.4
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• pp.1-6
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• 2004

In this paper, we investigate on the characteristics of poly-Si TFTs reuired for the implementation of analog circuits to be integrated with System-on-Glass (SoG). Matching requirements in terms of resistor values, threshold voltage and mobility of poly-Si TFTs are derived as a function of the resolution of display system. Effective mobility of poly-Si TFTs required for the realization of source driver is analyzed for various panel sizes.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.39-44
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• 2018

In this paper, we propose a monitoring method of smartphone to integrate IoT technology to monitor the state of the vehicle for fault diagnosis of E-Mobility power converter. In China, EV regulations are being implemented to promote technological development and market changes in electric vehicles. To meet this trend, E-Mobility should study suitable monitoring technology. The OBD-II method used in existing automobiles is a wired / wireless communication method. In order to apply it to E-Mobility, additional interface and communication link are required. In this paper, we propose a technology to monitor the status information of power converter for E-Mobility by combining existing technology with IoT. This technology simplifies the existing network protocol and hardware interface, and confirms that the E-Mobility power converter and smartphone can be interworked for easy user monitoring. And we have done research to make high value product design from the aspect of function.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.424-427
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• 2017

This study investigated the effect of strain on hole mobility and hole effective mass in a p-channel rectangular nanowire with two-dimensional confinement. We obtained the valence energy band structure using the six-band k.p method and calculated the mobility and effective mass of the hole in the [100] direction taking the strain effect into account in the inversion region. The hole mobility of strained silicon was calculated using Kubo-Greenwood formalism. As a result, it showed good performance compared to relaxed silicon, but its magnitude was insignificant.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1463-1466
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• 2002

This paper suggests the effective channel assignment scheme for mobility prediction handover. For maintaining required quality of service (QoS) during handover, there are handover algorithms these reserve the channel where the movement is predicted. But channel assignment schemes these have been studied are not considered mobility prediction handover. This paper suggests the channel assignment scheme that considers mobility predicted handover. The suggested algorithm maintains dropping probability of handover calls, decreases blocking probability of new calls and increases channel utilization.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.241-243
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• 2005

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.11-20
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• 2014

For Web-based applications in IoT environment, IETF CoRE WG has standardizing the CoAP. One of limitations of CoAP is that CoAP standard does not consider the mobility management of the CoAP sensor node. In this paper, we propose the mobility management protocol of CoAP sensor node by considering the characteristics of the constrained network. The proposed mobility management protocol supports for Web client to be transmitted the sensing data from CoAP node reliably while the CoAP sensor moves into different wireless networks. To do this, we designed the architecture with the separate IP address management of CoAP sensor node and presented the mobility management protocol, which includes the holding and binding mode, in order to provide the reliable transmission. Finally, the numerical analysis and simulation with NS2 tool have been done for the performance evaluation in terms of the handover latency and packet loss with comparing the proposed mobility management protocol with other the existing mobility management protocols. The performance result shows that the proposed mobility management can provide the transmission of sensing data without the packet loss comparing with the existing mobility management protocol reliably.