• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.931-936
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• 2006

This paper presents different issues of the real-time compression algorithms without compromising the video quality in the distributed environment. The theme of this research is to manage the critical processing stages (speed, information lost, redundancy, distortion) having better encoded ratio, without the fluctuation of quantization scale by using IP configuration. In this paper, different techniques such as distortion measure with searching method cover the block phenomenon with motion estimation process while passing technique and floating measurement is configured by discrete cosine transform (DCT) to reduce computational complexity which is implemented in this video codec. While delay of bits in encoded buffer side especially in real-time state is being controlled to produce the video with high quality and maintenance a low buffering delay. Our results show the performance accuracy gain with better achievement in all the above processes in an encouraging mode.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.281-284
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• 2002

Error resilience for image coding is an important component of multimedia communication system. Error resilience schemes address loss recovery from the compression perspective. Multiple description coding (MDC) is one of the error resilience techniques promising for robust video transmission. It is the way to achieve tradeoff description such as scalar quantization, correlating transform and the quantized frame expansion. In this paper, we consider Multiple Description Scalar Quantization (MDSQ) to wavelet domain. Conventional MDSQ schemes considered description with equal weights in each sub-bands. But, we can see that the each sub-bands is unequal contribution to whole image quality. Therefore, we experiment the multiple design MDSQ table to make probability of zero index high, which gives high efficiency in arithmetic symbol coder. We also compare our proposed method with the conventional methods and show improved performance in terms of redundancy-rate-distortion.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.39-42
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• 2005

H.264, a recently proposed international video coding standard, has adopted context-based adaptive variable length coding (CAVLC) as the entropy coding tool in the baseline profile. By combining an adaptive variable length coding technique with context modeling, we can achieve a high degree of redundancy reduction. However, CAVLC in H.264 has weakness that the correct prediction rate of the variable length coding (VLC) table is low in a complex area, such as the boundary of an object. In this paper, we propose a VLC table prediction scheme considering multiple reference blocks; the same position block of the previous frame and the neighboring blocks of the current frame. The proposed algorithm obtains the new weighting values considering correctness of the VLC table for each reference block. Using this method, we can enhance the prediction rate of the VLC table and reduce the bit-rate.

• Journal of Information Processing Systems
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• 제12권2호
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• pp.214-225
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• 2016

Global value numbering (GVN) is a method for detecting equivalent expressions in programs. Most of the GVN algorithms concentrate on detecting equalities among variables and hence, are limited in their ability to identify value-based redundancies. In this paper, we suggest improvements by which the efficient GVN algorithm by Gulwani and Necula (2007) can be made to detect expression equivalences that are required for identifying value based redundancies. The basic idea for doing so is to use an anticipability-based Join algorithm to compute more precise equivalence information at join points. We provide a proof of correctness of the improved algorithm and show that its running time is a polynomial in the number of expressions in the program.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.229-232
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• 2000

Orthogonal frequency division multiplexing(OFDM) has meanwhile become part of several telecommunicati ons standards, such as satellite and terrestrial digital audio broadcasting(DAB), digital terrestrial TV broad casting(DVB), asymmetric digital subscriber line(ADSL) for high-bit-rate digital subscriber services on twisted-pair channels, and broadband indoor wireless systems. In his paper, we show that OFDM signals contain sufficient structure to accomplish blind channel estimation using second order statistics only. This method doesn't require redundancy as cp in transmitter. And the result is compared with PSAM channel estimation as least square, linear minimum mean square, singular value decomposition.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.34-39
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• 2004

Huffman coding which has been used in many data compression algorithms is a popular data compression technique used to reduce statistical redundancy of a signal. It has been proposed that the Huffman algorithm can decode efficiently using characteristics of the Huffman tables and patterns of the Huffman codeword. We propose a new Huffman decoding algorithm which used a multi way tree search and present an efficient hardware implementation method. This algorithm has a small logic area and memory space and is optimized for high speed decoding. The proposed Huffman decoding algorithm can be applied for many multimedia systems such as MPEG audio decoder.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.456-465
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• 2003

It is well-known that bio-systems does not calculate inverse dynamics for trajectory planning, but they move by proper modulation of system impedances. Inspired by bio-systems, a biomimetic trajectory planning method is proposed in this work. This scheme is based on employment of redundant actuation which prevails in bio-systems. We discuss that for the generation of the biomimetic trajectory, intelligent structure of bio-systems plays an important role. Redundant actuation and kinematic redundancy fall into such a category of intelligent structure. The proposed biomimetic trajectory planning modulates the complete dynamic behavior such as natural frequencies and damping ratios by using the intelligent structure. Experimental work is illustrated to show the effectiveness of the proposed biomimetic trajectory planning for a five-bar mechanism with redundant actuators.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.157-163
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• 2002

Consideration for parallel operation in a high power system has been increased due to the advantages of parallel operation like as high productivity, simplicity of design, and redundancy of power. This paper discussed the parallel operation of DC-DC Converter, Which Can be used as a high power system, is studied. Based on the small signal model of DC-DC Converter, the simple and exact power stage model of parallel operation system is derived and the parallel operation system using current balance method for the uniform current distribution among the parallel operation system is discussed. To verify the high performance of the proposed DC-DC converter system for parallel operation, the simulation test of the parallel operation, which has 2 Converter modules, is accomplished.

• Journal of Astronomy and Space Sciences
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• 제15권2호
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• pp.499-508
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• 1998

다목적 실용위성 관계시스템의 SOS(Satelite Operations Subsystem) 서브시스템은 위성에서 보내온 원격측정 데이터를 처리하여 위성의 상태를 감시하고 위성으로 원격명령을 전송하는 업무를 수행한다. 본 논문에서는 SOS 서브시스템의 신뢰성 및 가용성을 향상시키기 위하여 하드웨어와 소프트웨어를 이중화하여 데이터 손실을 최소화하도록 설계한 SOS의 동족 고장관리(dynamic fault management) 기법에 대하여 기술하였다. 또한 구현의 정당성을 확인하기 위한 성능 시험 방법을 제시하였으며 그에 대한 결과를 분석하였다.

• 한국멀티미디어학회논문지
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• 제4권4호
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• pp.234-332
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• 2001

프랙탈 영상 부호화의 새로운 응용 분야인 프랙탈 영역 분할법의 YST방법은 주기점에 의한 라벨 붙이기와 프랙탈 변환에 의한 라벨 수정을 병용한 영역 분할법을 제안하였다. 그러나 이 개선법은 영역 분할의 질적인 개선은 가능하였으나, 여전히 라벨 붙이기와 라벨 수정의 과정에서 중복성이 남아 있다. 이 문제점의 해결방안으로 본 논문에서는 궤도에 따른 라벨 붙이기와 프랙탈 변환의 반복 과정에 관한 제약 조건을 제안한다.