• Annual Conference of KIPS
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• 2007.05a
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• pp.142-144
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• 2007

최근 인터넷 상에서는 UCC 붐이 일고 있다. PC상이 아닌 모바일 상에서의 UCC를 지향하며 모바일을 통해 칵테일 관련 동영상을 재생시키는 기술에 대하여 연구하였다. 칵테일에 대한 동영상을 직접 촬영하였으며 동영상 포맷을 모바일 상에서 적합한 형식으로 변환하는 과정을 겪었다. 다운로드 서버를 설계해 모바일 상에서 우리 팀이 촬영한 UCC 동영상을 다운로드 받을 수 있게 시스템을 구현하였다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.11
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• pp.184-193
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• 1998

In this paper, a real-time acoustic echo canceller is implemented using only PC's CPU without extra help from a DSP chip. The adaptive digital filter is designed efficiently so that it can be implemented in real-time and has a proper cancellation performance. It is proposed that a new double talk detector consumes a small computational complexity and guarantees the fast detection and robust operation. The real-time acoustic echo canceller consists of the full-duplex sound card and 166 MHz Pentium PC, and requires less than 10% CPU time.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.209-212
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• 2003

본 논문에서는 PC 환경에서 지상파 디지털 멀티미디어 방송(Digital Multimedia Broadcasting, DMB)을 수신할 수 있는 PC 기반 지상파 DMB 수신기용 백엔드 시스템 개발에 대해 서술한다. 지상파 DMB는 기존의 지상파 아날로그 또는 디지털 TV에 비해 탁월한 이동 수신 성능을 보인다. 본 논문에서는 국내 지상파 DMB 표준안에 부합하는 수신기의 백엔드 (back-end)를 PC 환경에서 소프트웨어로 구현하였다. 지상파 DMB는 유럽의 디지털 오디오 방송(Digital Audio Broadcasting, DAB) 표준인 EUREKA-147을 기반으로 MPEG-4 표준에 의한 멀티미디어 서비스를 제공한다. 지상파 DMB의 멀티미디어 서비스는 MPEG-4 AVC(Advance Video Coding) 압축 비디오와 BSAC(Bit Slice Arithmetic Coding) 압축 오디오를 MPEG-4 시스템의 SL(Sync Layer) 표준으로 패킷화 후 MPEG-2 TS(Transport Stream)에 실어 DAB의 스티림 모드를 통해 전송하는 방식을 사용한다. 본 논문에서는, 지상파 DMB 수신을 위한 프론트엔드(front-end)는 외장형 기기를 이용하고, 이로부터 USB 인터페이스를 통해 기저대역 다중화 스트림을 PC 상으로 업로드한 뒤, 소프트웨어에 의해 역다중화하고 압축을 푼 후, 오디오와 비디오를 재생하는 지상파 DMB 백엔드 시스템을 구현하고 이를 검증하였다.

• Journal of Practical Engineering Education
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• v.7 no.1
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• pp.31-37
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• 2015

Terrestrial digital multimedia broadcasting (TDMB) is a method of bringing multimedia images, radio, internet, and television to portable devices through terrestrial digital radio transmissions. TDMB related educations being carried out in colleges are focusing on developing firmware which enables users to choose a wanted service. TDMB transmission frame is made up of synchronization channel (SC), fast information channel (FIC), and main service channel (MSC). Services such as video, audio and date are transmitted in the form of subchannel in the MSC. FIC carries information related to each services and subchannels. This paper presents a TDMB frame analysis simulator for analyzing and displaying FIC data on PC. TDMB frame analysis simulator contains functions such as controlling TDMB receiver through USB, establishing the frequency, bringing FIC to PC, displaying ensemble ID and levels, and displaying informations related to services and subchannels. In addition to that, this simulator has a function of being able to store FIC date and subchannel data. This simulator being developed with C++ is expected to be used to view those data visually so that it helps students to understand the TDMB system better and bring about the educational motivation.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.76-81
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• 2006

A PDA is used mainly for downloading data from a stationary server such as a desktop PC in an infrastructure network based on wireless LAN. Thus, the overall performance depends heavily on the performance of such downloading with PDA. Unfortunately, for a PDA the time taken to receive data from a PC is longer than the time taken to send it by 53%. Thus, we measured and analyzed all possible factors that could cause the receiving time of a PDA to be delayed with a test bed system. There are crucial factors: the TCP window size, file access time of a PDA, and the inter-packet delay that affects the receiving time of a PDA. The window size of a PDA during the downstream is reduced dramatically to 686 bytes from 32,581 bytes. In addition, because flash memory is embedded into a PDA, writing data into the flash memory takes twice as long as reading the data from it. To alleviate these, we propose three distinct remedies: First, in order to keep the window size at a sender constant, both the size of a socket send buffer for a desktop PC and the size of a socket receive buffer for a PDA should be increased. Second, to shorten its internal file access time, the size of an application buffer implemented in an application should be doubled. Finally, the inter-packet delay of a PDA and a desktop PC at the application layer should be adjusted asymmetrically to lower the traffic bottleneck between these heterogeneous terminals.

• Journal of Korea Multimedia Society
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• v.14 no.8
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• pp.1041-1049
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• 2011

According to the development of society and infrastructure, effective underground facility management is growing more important them ever. In the process various monitoring systems are studied and developed for water works pipe-network. Especially, RTD-1000 system with the based on Pc. Reflector-monitoring device is constructed and steered by several local governments. But, this system have to be improved result from based on PC system structure at the point of resource management, heat, power consumption and size. In this paper, RTD-2000 is proposed are a substitution of improved RTD-1000 with many respect and portable one. This system is designed and implemented with ARM-9 development kit based on WinCE and LCD eliminate TDR(Time Domain Reflector-Meter). Various surveillance programs based on windows are mounted on RTD-1000 are replaced with dedicated embedded application softwares. Simulation and evaluation for performance comparison are performed for the prove of effectiveness of RTD-2000.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.873-892
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• 1998

In this paper, we propose an architecture of multimedia communication terminal that can e used in broadband ISDN environments. To design and implement the multimedia communication terminal, we analyzed the structure of multimedia terminals and the types of services which is recommended by public and private standard or ganization, such as ITU-T, Digital Audio-Visual Council(davic) and ATM Forum. The multifunctional communication terminal designed in this paper could allow inter-working between existing communication terminals on the heterogeneousnetwork and accept current and advanced multimedia communication application flexible. An implemented terminal is consisted of the multimedia processing board and the ATm interface board that is installed in PCI bus on personal computer. The integrated service multimedia communication terminal that is implemented supports retrieval, distributive and conversational communication service simultaneously. And then we performaned functional module test according to the individual communication services.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.217-227
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• 2003

This paper describes an implementation of the slide-show functionality, which is one of the services that can be provided by the Digital Multimedia Broadcasting (DMB). While the existing analog radio broadcasting services provide audio only, DMB slide-show is the functionality that can deliver still images associated with the audio. For example, it can deliver the photographs of the singer, album cover images, or the lyrics of the song that correspond to the audio. There are two modes for the transmission of the slide-show. Firstly. the program-associated data (PAD) field within the DMB audio frame can be utilized and secondly, the slide-show data can be transmitted, after being multiplexed, with other service data as individual data stream separated from the audio. This paper describes PC-based implementations of a transmitter-side module that inserts slide-show data into the PAD area within audio bitstream and a receiver-side application module that plays the slide-show through decoding the PAD within the received audio bitstream and demonstrates their validity through experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3076-3082
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• 2010

The techniques and the products which use various video compression codec are come out from army or civil field. In existing high-end PC environment, process of the video compression codec does not become a problem, but in embedded system environments which limited system resources, because the system load due to the high-resolution images compressed by high-density, issues of performance and utilization are highlighted. This paper proposes the DirectShow Filter interfaces which are a hardware method in order to solve the problem existing software algorithms for image compression performance and peripheral interfaces.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.495-507
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• 2006

In wireless local area networks (WLANs), the successful design of scheduling algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a multipolling-based dynamic scheduling algorithm for providing delay guarantees to multimedia traffics such as MPEG streams. The dynamic algorithm exploits the characteristics of MPEG stream, and uses mini frames for feedback control in order to deliver dynamic parameters for channel requests from stations to the point coordinator (PC) operating at the access point (AP). In this scheme, the duration of channel time allocated to a station during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to conventional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound.