• 한국통신학회논문지
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• 제30권4B호
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• pp.202-209
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• 2005

본 논문에서는 first-hop 무선 채널을 갖는 무-유선망에서 채널 특성에 따라 코딩 비트율을 조절할 수 있는 동적 TCP-friendly 비트율 제어방식 (TFRC)을 제안한다. 제안되는 비트율 제어 기법은 무선망을 통해 전송되는 멀티미디어 플로우의 QoS 성능 저하 현상을 피하기 위해 패킷 손실 통계자료를 이용한 새로운 무선 손실 구별 알고리즘을 사용하고 있다. 이 알고리즘은 무-유선망에서 TCP 플로우와 함께 백본 대역폭을 공유하는 동안 TCP-friendly하도록 비트율을 생성한다. 실험 결과를 통해 제안하는 비트율 제어방식의 시스템은 TFRC 흐름 제어에서 무선 손실의 영향을 제거하고 신뢰성이 낮은 무선 링크에 의해서 발생되는 비디오 스트림의 갑작스런 품질 저하 현상을 상당히 줄일 수 있음을 알 수 있다.

• ETRI Journal
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• 제32권6호
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• pp.863-870
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• 2010

In recent years, the development of multimedia devices has meant that a wider multimedia streaming service can be supported, and there are now many ways in which TV channels can communicate with different terminals. Generally, scalable video streaming is known to provide more efficient channel capacity than simulcast video streaming. Simulcast video streaming requires a large network bandwidth for all resolutions, but scalable video streaming needs only one flow for all resolutions. In previous research, scalable video streaming has been compared with simulcast video streaming for network channel capacity, in two user simulation environments. The simulation results show that the channel capacity of SVC is 16% to 20% smaller than AVC, but scalable video streaming is not efficient because of the limit of the present network framework. In this paper, we propose a new network framework with an SVC extractor. The proposed network framework shows a channel capacity 50% (maximum) lower than that found in previous research studies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.566-569
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• 2001

Researchers have invectigated nasal flow both numerically and experimentally for centuries. Experimental studies most have suffered from various limitations necessary to allow the measurements to be obtained with available equipment. Nasal airflow can be subdivided into two interrelated categories; nasal airflow resistance and heat and mass transfer between the air stream and the walls of the nasal cavity. In this study, thanks to a new method for model casting by a combination of Rapid prototyping and Solidification of clear silicone, a transparent rectangular box containing the complex nasal cavity is made for PIV experiments. The CBC PIV algorithm is used for analysis.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.887-890
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• 1998

We present a novel multi-resolution block matching algorithm (BMA) for fast motion estimation. At the coarsest level, a full search BMA (FSBMA) is performed for searching complex or random motion. Concurrently, spatial correlation of motion vector (MV) field is used for searching continuous motion. Here we present an efficient method for searching full resolution MVs without MV decimation even at the coarsest leve. After the coarsest level search, two or three initial MV candidates are chosen for the next level. At the further levels, the MV candidates are refined within much smaller search areas. Simulation results show that in comparison with FSBMA, the proposed BMA achieves a speed-up factor over 710 with minor PSNR degradation of 0.2dB at most, under a normal MPEG2 coding environment. Furthermore, our scheme is also suitable for hardware implementation due to regular data-flow.

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.1-9
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• 2020

Many cryptographic and error control coding algorithms rely on finite field GF(2m) arithmetic. Hardware implementation of these algorithms needs an efficient realization of finite field arithmetic operations. Finite field multiplication is complicated among the basic operations, and it is employed in field exponentiation and division operations. Various algorithms and architectures are proposed in the literature for hardware implementation of finite field multiplication to achieve a reduction in area and delay. In this paper, a low area and delay efficient semi-systolic multiplier over finite fields GF(2m) using the modified Montgomery modular multiplication (MMM) is presented. The least significant bit (LSB)-first multiplication and two-level parallel computing scheme are considered to improve the cell delay, latency, and area-time (AT) complexity. The proposed method has the features of regularity, modularity, and unidirectional data flow and offers a considerable improvement in AT complexity compared with related multipliers. The proposed multiplier can be used as a kernel circuit for exponentiation/division and multiplication.

• 대한기계학회논문집B
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• 제26권6호
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• pp.811-816
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• 2002

For the first time, airflow in the nasal cavity of a normal Korean adult is investigated experimentally by PIV measurement. Nasal airflow can be subdivided into two interrelated categories; nasal airflow resistance and heat and mass transfer between the air stream and the walls of the nasal cavity. In this study, thanks to a new method for the model casting by a combination of the rapid prototyping and curing of clear silicone. a transparent rectangular box containing the complex nasal cavity can be made fur PIV experiments. The CBC PIV algorithm is used for analysis. Average and RMS distributions are obtained for inspirational and expiration nasal airflows. Data fer the airflow at the end of meatuses are obtained for the first time. Comparisons between western and Korean nasal airflows are appreciated. Due to the difference in geometry of the frontal part of nasal cavity, the flow near nares shows the difference.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.815-818
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• 1998

Hardware formal verification involves the use of analytical techniques to prove that the implementation of a system confroms to the specification. The specification could be a set of properties that the system must have or it could be an alternative representation of the system behavior. We can represent our behavioral specification to be written in VHDL coding. In this paper, we proposed a new hardware design verification method. For theis method, we assumed that a verification pattern already exists and try to make an algorithm to find a place where a design error occurred. This method uses an hierarchical approach by making control flow graph(CFG) hierarchically. From the simulation, this method was turned out to be very effective that all the assumed design errors could be detected.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.290-296
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• 2008

In this paper development of on-line data visualization program is described and some examples of data postprocessing are shown. The program is written in JAVA language and runs as a JAVA applet on the web browser such as Internet Explorer or Firefox. Remote users can use the program to visualize and analyze their own flow data by accessing the program server through the internet and loading data files in proper formats from their local computers. This paper describes briefly about algorithms for data visualization, structure and available functions of the program, and web sever system. The mechanism of how the JAVA applet can access and process local data files and relevant coding techniques are explained as well. Also explained is what is required for the remote users and client computers to access the program on-line. Some visualization examples performed on a local computer are illustrated by accessing the server remotely.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.290-296
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• 2008

In this paper development of on-line data visualization program is described and some examples of data postprocessing are shown. The program is written in JAVA language and runs as a JAVA applet on the web browser such as Internet Explorer or Firefox. Remote users can use the program to visualize and analyze their own flow data by accessing the program server through the internet and loading data files in proper formats from their local computers. This paper describes briefly about algorithms for data visualization, structure and available functions of the program, and web sever system. The mechanism of how the JAVA applet can access and process local data files and relevant coding techniques are explained as well. Also explained is what is required for the remote users and client computers to access the program on-line. Some visualization examples performed on a local computer are illustrated by accessing the server remotely.

• 한국컴퓨터정보학회논문지
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• 제20권6호
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• pp.151-159
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• 2015

In traditional programing education, computers were used as the main tool. Consequently, it was problematic to provide education in an environment without computers or for learners without computer skills. To address this problem, this study developed and validated an unplugged robot education system capable of computerless programming education. The key feature of the proposed system is that programing can be done only by connecting programming blocks in symbols of a flow chart with built-in commands. Validation of the system was performed by a specialist group. Validity was very high with values of content validity ratio (CVR) over 0.7 in all evaluation criteria except "Ease of error debugging" and "Linkages to educational curriculum," whose CVR values were each 0.6. Future directions include improvement in the two areas that scored lower than the others did by, respectively, system improvement to support debugging in error conditions that may occur during the programming process, and development of user guide to support linkages to educational curriculum.