• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.207-221
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• 2006

A fully automatic and computationally efficient method is proposed for intelligent display of soccer video on small multimedia mobile devices. The rapid progress of the multimedia signal processing has contributed to the extensive use of multimedia devices with a small LCD panel. With these emerging small mobile devices, the video sequences captured for standard- or HDTV broadcasting may give the small-display-viewers uncomfortable experiences in understanding what is happening in a scene. For instance, in a soccer video sequence taken by a long-shot camera technique, the tiny objects (e.g., soccer ball and players) may not be clearly viewed on the small LCD panel. Thus, an intelligent display technique is needed for small-display-viewers. To this end, one of the key technologies is to determine region of interest (ROI), which is a part of the scene that viewers pay more attention to than other regions. In this paper, the focus is on soccer video display for mobile devices. Instead of taking visual saliency into account, we take domain-specific approach to exploit the characteristics of the soccer video. The proposed scheme includes three modules; ground color learning, shot classification, and ROI determination. The experimental results show the propose scheme is capable of intelligent video display on mobile devices.

• Journal of KIISE:Information Networking
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• v.37 no.4
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• pp.272-283
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• 2010

Wireless Mesh Networks (WMNs) have gained a lot of attention recently. Based on the characteristic of WMNs as a highly connected wireless infrastructure, many efforts from research organizations are made in order to improve the performance of the flow throughput in WMNs. Therefore, it is very critical issue to establish efficient routing paths for multiple concurrent ongoing flows. In this paper, we propose a general modeling methodology to analyze the end-to-end throughput of multiple concurrent flows by analytical calculation taking into account the carrier sensing behaviors, interference and the IEEE 802.11 Distributed Coordination Function mechanism. After the comparison of the average service time for each successful transmission at each node, we analyze the bottlenecks of flows, and hence obtain the maximum end-to-end throughput of them. By using our proposed model, it is possible to predicate the throughput of several candidate routing paths for multiple concurrent ongoing data flows, so we can select the most efficient route that can achieve the highest throughput. We carry out simulations with various traffic patterns of multiple flows in WMNs to validate our modeling and our efficient route selection mechanism.

• Journal of KIISE:Information Networking
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• v.32 no.5
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• pp.615-624
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• 2005

In Mobile IP, several types of messages - binding update, binding request and binding acknowledgement - are used to support user mobility. It is necessary to exchange those messages frequently for seamless mobility but it incurs both the increase of network overhead and poor usage of mobile node battery power Thus, we need a mechanism that the server detects users location and also copes with the problems effectively, which is our main concern in this paper Each user records all moving logs locally and periodically makes out profile based on them in HMIPv6. By using profile, estimated resident time can be computed whenever he enters an area and the time is set up as the binding update message lifetime. Of course, the more correct lifetime nay be obtained IP arrival time as well as average resident time Is considered in profile. Through extensive experiments, we measure the bandwidth usage for binding update messages by comparing the proposed schemes with that in HMIPv6. From the results, Gain gets over $80\%$ when mobile node stays more than 13 minutes in a subnet. Namely, we come to know that our schemes improve network usage and energy usage in mobile node by decreasing the number of messages while they also manage users locations like that in HMIPv6.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.73-80
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• 2012

In this article, we propose a P2P-based mobility management protocol for global seamless handover in heterogeneous wireless networks. Unlike previous mobility management protocols such as IETF MIPv4/6 and its variants, the proposed protocol can support global seamless handover without changing the existing network infrastructure. The idea of the proposed protocol is that the location management function for mobility management is separately supported from packet forwarding function, and bidirectional IP tunnels for packet transmission are dynamically constructed between two end-to-end mobile hosts. In addition, early handover techniques have been developed to avoid large handover delays and packet losses using the IEEE 802.21 Media Independent Handover functions. The architecture and signaling procedure of the proposed protocol have been designed in detail, and the mathematical analysis and simulation have been done for performance evaluation. The performance results show that the proposed protocol outperforms the existing MIPv6 and HMIPv6 in terms of handover latency and packet loss.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.750-761
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• 2011

Currently, 3DTV technologies are being developed as the future services of the HD digital broadcast environment. As one of the various research topics to apply 3DTV technologies to the conventional broadcasting network, methods to configure stereoscopic videos are being studied. In this paper, we proposed a method to broadcast high quality stereoscopic videos based on analysis of a method to add a stereoscopic descriptor to the PMT of MPEG-2 transport streams and a method to transmit stereoscopic videos by the expansion of MPEG-C part 3 which are from precedent studies. The proposed technique maintains compatibility with conventional MPEG-2 transport streams by showing only reference video for models that do not support 3D broadcasting. Therefore, the compatibility between conventional broadcasting and stereoscopic videos should make this method useful when activating 3D services in the communications and broadcasting area

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.844-853
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• 2008

This paper describes the design of a FEM(Front End Module) having power detection function for mobile handset application. The designed FEM consists of a MMIC(Monolithic Microwave Integrated Circuits) power amplifier chip, SAW Tx filter and duplexer, diode power detector and stripline matching circuit. An LTCC(Low Temperature Co-fired Ceramics) technology is adopted for miniaturized FEM. The frequency band is $824{\sim}869$ MHz which is the uplink Tx band of the CDMA mobile system. The size of designed FEM is $7.0{\times}5.5{\times}1.5\;mm^3$, which is an ultra-small size even though the power detector circuit is included. All sub-components of FEM have been developed and measured in advance before being integrated into FEM. The measured output power and gain are 27 dBm and 27 dB, respectively. In addition, the measured ACPR characteristics are 46.59 dBc and 55.5 dBc at 885 kHz and 1.98 MHz offset, respectively.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.22-27
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• 2002

The 25 Watt hybrid MIC SSPA has been developed in the frequency rang from 1.6265 GHz to 1.6465 GHz for uplink of INMARST's earth station. To simplify the fabrication process, the whole system is designed of two parts composed of a friving amplifier and a power amplifier. The Motorolas MRF-6401 is used for driving part, the Motorolas MRF-16006 and MRF-16030 is used the power amplifier. We reduced weight and volume of high power amplifier through arranging the bias circuits in the same housing. The realized SSPA has more than 30 dB for gain within 20 MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output port are less than 1.7, respectively. The output power of 44 dBm is achieved at the 1 dB gain compression point of 106365 GHz These results reveal a high power amplifier of 25 Watt which is the design target. The Proposed SSPA manufacture techniques in this paper can be applied to the implementation of high power amplifiers for some radars and SCPC.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.20 no.5
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• pp.17-22
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• 2002

만약 사용자가 원하는 멀티미디어 콘텐츠를 원하는 시간에 TV를 통해서 볼 수 있게 된다면, 다시 말해서 보고 싶을 때, 보고 싶은 방송을 포함한 멀티미디어 콘텐츠를 원하는 시간에 바로 볼 수 있게 된다면 사용자는 방송시간에 맞추어 TV를 보지 않아도 되고 원하는 콘텐츠를 검색하느라 시간을 보낼 필요도 없어질 것이다. 예약 녹화의 경우에는 시간정보를 가지고 미리 예약을 해야 하는 경우이므로 이와는 다른 경우라 하겠다. 이러한 서비스는 바로 디지털 콘텐츠와 이를 가정에서 저장할 수 있는 장치의 발달이 바탕이 되고 있다.(표 1 생략, 원문이미지 참조) 표 1은 영국의 BBC사에서 1998년에 조사한 자료로 디지털 멀티미디어 데이터를 저장하고 재생할 수 있는 저장장치의 가격과 용량의 전망을 나타낸다. 여기에서 데이터는 5.5 Mbps급의 MPEG-2 스트림을 기준으로 하였다. 표 1에서 보수적 견해는 매 18개월마다, 현실적 견해는 매 10개월마다 동일 가격의 용량이 2배가 되는 것으로 계산한 것이다. 여기서 보듯 저장장치의 가격 대비 성능이 갈수록 나아지고 있어 가정에서 멀티미디어 콘텐츠를 저장할 수 있는 가정용 서버의 등장이 멀지 않았음을 보여준다. 1999년 가을에 활동을 접은 DAVIC의 마지막 활동이 바로 이러한 저장장치를 이용한 "TV Anytime Service"였다 . Anytime Ser vice란 저장장치를 통해 사용자가 원하는 콘텐츠를 저장해 놓았다가 사용자가 원하는 시간에 언제나 볼 수 있다는 개념이다. 이를 소비자관점에서 보면 Personalized service라고 할 수 있다. 이어 1999년 여름에 창설이 된 "TV Anytime Forum"이라는 단체에서 이러한 저장장치를 이용한 서비스를 위한 환경을 구축하고 있다. TV Anytime Forum은 가정에서 저장장치가 있는 단말인 PDR(Personal Digital Recorder)을 이용한 서비스, 즉 Anytime Service 위한 응용을 가능하게 하기위한 콘텐트 개발자에서부터 가전기기에 이르는 분야에서 Interoperable한 규격을 만들어 보자는 것이 그 목적이다. 특히 여러가지 디지털미디어 전달방식, 예를 들어 DVB, ATSC, ARIB 등에 독립적인 규격을 만드는 것을 원칙으로 하고 있다. 1999년 7월에 첫 번째 회의를 하면서 설립이 되었다. 2001년 말 기준으로 BBC, NHK, Microsoft, Sony, IBM, Phillips, NTT, Intel, Canal+, Tivo, 대우전자, 삼성전자, LG전자, KETI, ETRI 등 콘텐츠 사업자, 방송업자, 네트웍 사업자, 가전업체, 소프트웨어 개발회상에 이르기까지 총 157개 회원사로 구성되어 있으며 년 6회 회의를 개최한다. 2000년 11월에는 서울에서 회의를 개최하였으며 2003년 6월에 다시 한국에서 개최하기로 확정되어 있다. 본 글에서는 이러한 Anytime Service 환경이 구축되었을 때의 각 산업별로 얻을 수 있는 이득에 대해서 알아보고 TV Anytime Forum의 각 Working Group들의 작업 내용들, 그리고 지난 1월에 열렸던 15차 회의의 결과들에 대해서 살펴보고 국내의 TV Anytime 활동에 대해서 간단하게 소개하고 마치도록 하겠다. 현재 디지털 방송기술, 비디오 스트리밍 기술이나 MPEG 등과 같은 기술수준으로도 충분히 이러한 서비스를 시작할 수 있으며 소비자들도 이러한 욕구를 서서히 느끼고 있다. 정보와 서비스를 선택할 수 있게 만들자는 목표를 설정하고 있다. 이러 목표는 통신$.$컴퓨터$.$멀티미디어 기술발전으로 가능하게 되었다.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.1
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• pp.7-14
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• 2013

Presently, there are many different technologies used for position detection. However, as signal-receiving devices operating in different locations must detect the precise position of objects located at long distances, it is essential to know the precise time at which an object's or a user's terminal device sends a signal. For this purpose, the existing time of arrival (ToA) technology is not sufficiently reliable, and the existing time difference of arrival (TDoA) technology is more suitable. If a TDoA-based electric surveillance system and other tracking devices fail to achieve precise time-synchronization between devices with separation distance operation, it is impossible to obtain correct TDoA values from the signals sent by the signal-receiving devices; this failure to obtain the correct values directly affects the location estimation error. For this reason, the technology for achieving precise time synchronization between signal-receiving devices in separation distance operation, among the technologies previously mentioned, is a core technology for detecting TDoA-based locations. In this paper, the accuracy of the proposed time synchronization and the measurement error in the TDoA-based location detection technology is evaluated. The TDoA-based location measurement error is significantly improved when using the proposed method for time-synchronization error reduction.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.391-403
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• 2005

Several nv6 mobility support protocols for mobile Internet services are proposed in IETP : Mobile Ipv6, Hierarchical Mobile Ipv6, and Fast Handovers over Mobile Ipv6. Recently, IEEE 802.11 network has also been widely deployed in public areas for mobile Internet services. In the near future, IPv6 mobility support over IEEE 802.11 network is expected to be a key function to actualize the All If-based mobile various services. For appropriate application of these protocols, the IPv6 mobility support protocols should be analyzed according to their characteristics in terms of signaling, handover latency, lost packets, and required buffer sire as well as the impact of lower layer such as IEEE 802.11 network. In this paper, we analyze the performance of the protocols over IEEE 802.11 network. We define a packet-level traffic model, a network system model, and a mobility model. From these models, we construct a framework for the performance analysis. We also make cost functions to formalize each protocol's performance. Lastly, we analyze the effect of varying parameters used to show diverse numerical results, and compare with each other. From the analysis results, it is concluded that each Protocol has contrary or contrastive advantages with other Protocols, so there is no protocol that holds a dominant position.