• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.163-166
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• 2003

In recent years, there has been increased to access multimedia service through the Internet due to rise of the access speed. We suppose the co-existence of the various access networks in adjacent area in the future, such as wireless LAN, Bluetooth, and 3G Cellular So, the size of the cell will be smaller and the number of access point will be increased. In other words, the potable devices need the efficient mobility scheme due to move between cells frequently Currently, the several of the scheme, which is Cellular IP, HAWAII, Mobile IPv4 regional registration, and hierarchical Mobile IPv6, is suggested to support micro-mobility but Mobile IPv4 is standard scheme to support the mobility of the mobile node. MPLS, which forwards the packet through switching instead of routing using IP address, has begun to deploy in the internet backbone to increase the performance of mobility protocol. The integration of both MPLS and Mobile IP improves the scalability of the Mobile IP data forwarding process by leveraging on the features MPLS which are fast switching and high scalability. Moreover it abbreviates IP-in-IP tunneling between HA and FA. In this paper, we suggest efficient mobility scheme through integration of both MPLS and hierarchical Mobile IPv6.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.522-528
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• 2004

Mobile internet service based on CDMA network evolution and multifunction mobile terminal is popular in Korea. Mobile internet service is classified as the information service using browser and mobile multimedia service using download platform. Killer applications based on multifunction mobile terminals have been developed for new business in mobile internet services. One of killer applications is location based seurvice (LBS) using mobile location information. In this paper, we develop mobile map browser using WIPI platform that is the main function in LBS. Mobile map browser interworking with GIS server provides the map information. The developed mobile map browser can be working on PDA and telematics terminals when WIPI is porting on these devices.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.251-258
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• 2006

When producing a wireless web contents by using wire web contents for PC environment, we should consider how to represent lots of information being suitable with PC environment to wireless devices having narrow performance. Therefore, we propose mobile page editor for manager to select and modify specific contents with the existing wire web page. Also, we try to define an intermediate language based on DID(Digital Item Declaration) of MPEG-21 multimedia framework which defines source of converting information and wireless web contents generating at mobile editor in considering real time service problem when transcoding multimedia information in a web server into wireless device having low resolution, narrow performance of media process, memory, and so on.

• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.971-978
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• 2009

The paper is a phase controlled loop antenna for multi-media devices. We developed a phase control loop pattern arrangement methods for loop antenna in mobile devices like as a cell phone and PCS, WCDMA. In the loop antenna pattern, arrange close adhesive the loop antenna pattern $180^\circ$ cycle in wave length, the radiated electro-magnetic wave from close adhesive loop pattern become to coherent wave than the phase controlled loop antenna has high efficiency and high radiation gain. To acquire a wide band width on phase controlled loop antenna, we arrange a multiple phase controlled loop pattern that has a different length each other. Different length for each other loop pattern cause a different frequency that we can acquire a wide band width for loop antenna from close adhesive phase control. In experiment, we designed a CDMA850 mobile multi-media antenna in 20mm$\times$20mm area thickness 0.4mm, the radiation efficiency is over 60% and radiation gain is over 0dBi.

• Journal of Korea Multimedia Society
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• v.22 no.11
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• pp.1215-1222
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• 2019

Recently, people with disabilities also search for and collect information from the web through smart devices, and save collected information on smart devices or take notes. For non-disabled people, various memo applications are provided on the market, so it is more convenient to choose according to their preference. However, existing memo services are limited for use by blind people due to the importance of visual information. The problem with blind people when using smart devices is that the screen is not recognized, so it is not possible to check in which location the menu of the application exists. In addition, it is difficult to input and manipulate text, and systematic file management and control are not possible. Therefore, in this paper, we propose the development of voice memo service that blind people can use only voice and hearing information and can operate menu with Bluetooth remote controller. We will develop a system that includes a comprehensive voice file management function for storing, searching, playing, and deleting files, rather than simply storing voice files.

• The KIPS Transactions:PartD
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• v.15D no.3
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• pp.411-420
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• 2008

This paper implemented the u-Healthcare Context Information System (HCIS) supporting ubiquitous healthcare by using location, health and titrating environment information collected from sensors/devices equipped in home for healthcare home service. The HCIS is based on the Distributed Object Group Framework (DOGF), a management model which can customize distributed resources, and manages various context information, applications and devices as a group in healthcare home environment, as one more logical units. Also, this system provides continuous healthcare multimedia service considering a resident's location using Mobile Proxy, and the healthcare context information through Context Provider to a resident in home. For verifying execution of our system, we implemented the seamless multimedia service based on resident's location and the prescription/advice and schedule notification/alarm service as healthcare applications in home. And we showed the executing results of healthcare home service by using service device existed in the residential space on which the resident is located according to the healthcare scenario.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1282-1291
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• 2005

This paper presents the EVM(Embedded Virtual Machine) which enables the execution of dynamic applications loaded in the embedded systems such as Mobile Devices(mobile phone, PDA), Set-Top Box, and Digital TV using downloading techniques. To accomplish this goal, we defined a SIL-(Standard Intermediate Language) code, and implemented a Bytecode-to-SIL translator which enables the execution of programs written in java language in the EVM platform without JVM, and a MSIL--to-SIL- translator which enables for programs written in .NET language to be executed in the EVM platform without .NET platform. Also, we developed a EFF(Executable File Format) builder as an assembler which translates SIL codes into an executable file, *.evm, and implemented the EVM which reads the *.evm file and executes it. The virtual machine for embedded systems developed in this paper is the software technologies that enable the execution of applications or contents without changes to when the platforms change. In fact, the virtual machine suggested here is not only usable as a standard model for existing virtual machines but also aid in more efficient execution of applications loaded in the embedded systems such as Mobile Devices, Digital TV, and Set-Top Box.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.483-488
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• 2010

Due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services. Moreover, the user can service the participatory video broadcasting service in the mobile device and it can be used to deliver the real-time news and more variety information in the user side. Live multimedia service of user participation should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived QoS (Quality of Service) of streaming service. In this paper, we propose an adaptive rate control scheme, called DeBuG (Delay Bounds Guaranteed), to guarantee the delay bounds and continuity of video playback for the real-time streaming in mobile devices. In order to provide those, the proposed scheme has a quality adaptation function based on the transmission buffer status and network status awareness. It also has a selective frame dropper, which is based on the media priority, before the transmission video frames. The simulation results demonstrate the effectiveness of our proposed scheme.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.2
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• pp.100-107
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• 2011

As the use of mobile multimedia devices is increasing in the recent year, the needs for high-performance multimedia processors are increasing. In this regard, we propose a SIMD (Single Instruction Multiple Data) based parallel processor that supports high-performance multimedia applications with low energy consumption. The proposed parallel processor consists of 16 processing elements(PEs) and operates on a 3-stage pipelining. Experimental results for the JPEG encoding algorithm indicate that the proposed parallel processor outperforms conventional parallel processors in terms of performance and energy efficiency. In addition, the proposed parallel processor architecture was developed and verified with verilog HDL and a FPGA prototype system.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.196-199
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• 2008

최근의 모바일 기기들이 다양한 진동 패턴을 제공하면서 모바일 기기에서의 촉감 제공과 관련된 연구들이 활발히 진행되고 있다. 그러나 대부분의 연구에서는 특정 메시지를 추상적인 진동 패턴으로 상징화 시킬 뿐 현실적인 촉감 제공에 관한 연구는 많지 않다. 본 논문에서는 모바일 기기에서 보다 현실적인 촉감 제공을 위한 진동 패턴에 대해 논의하고, 압전 액츄에이터를 사용하여 스크롤 상황을 그대로 표현할 수 있는 진동 패턴을 제작하였다. 그리고 스크롤 상황을 표현하는 여러 가지 진동 패턴과 진동의 이동 시간에 따라 느낌 평가 및 스크롤 방향에 대한 인식률 평가를 실시하였다. 평가 결과 12 가지의 스크롤 방향에 대해 80% 이상의 인식률을 보였고, 여러 가지 스크롤 패턴 형태와 스크롤 진동의 이동 시간에 따라 다양한 스크롤 촉감을 가질 수 있다는 결과를 얻을 수 있었다. 이러한 결과를 통해 앞으로 모바일 기기에서 좀 더 현실적인 촉감 제공이 가능할 것으로 기대된다.