• 전자공학회논문지 IE
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• v.46 no.1
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• pp.1-6
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• 2009

This paper presents the digital PLL architecture and design for improving the frequency detection range and locking time for wide-band frequency synthesizer applications. In this research, a wide-range digital logic quadricorrelator is used for wide-band and fast frequency detector and sigma-delta modulator with 2-bit up-down counter is adopted for DCO control. The proposed digital PLL reduces the phase noise from quantization effect and is suitable for implementation of wide-band fast-locking as well as low power features, which is in high demand for mobile multimedia applications.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1097-1100
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• 1999

Due to the significant computation of full search in motion estimation, extensive research in fast motion estimation algorithms has been carried out. However, most of the algorithms have the degradation in predicted images compared with the full search algorithm. To reduce an amount of significant computation while keeping the same prediction quality of the full search, we propose a fast block-matching algorithm based on gradient magnitude of reference block without any degradation of predicted image. By using Taylor series expansion, we show that the block matching errors between reference block and candidate block are proportional to the gradient magnitude of matching block. With the derived result, we propose fast full search algorithm with adaptively determined scan direction in the block matching. Experimentally, our proposed algorithm is very efficient in terms of computational speedup and has the smallest computation among all the conventional full search algorithms. Therefore, our algorithm is useful in VLSI implementation of video encoder requiring real-time application.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.1
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• pp.79-84
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• 2020

In this article, we implement a recently developed fast Monte Carlo simulation (MCS) for pricing equity-linked securities (ELS), which is most commonly issued autocallable structured financial derivative in South Korea, on the mobile platform. The fast MCS is based on Brownian bridge technique. Although mobile platform devices are easy to carry around, mobile platform devices are slow in computation compared to desktop computers. Therefore, it is essential to use a fast algorithm for pricing ELS on the mobile platform. The computational results demonstrate the practicability of Android application implementation for pricing ELS.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3207-3209
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• 2000

X-ray CT(Computed Tomography) has been a good modality for non-invasive diagnosis and recently, Conventional CT has been replaced rapidly with Spiral CT in recent. In X-ray CT, spiral scanning has various advantages such as better image quality, reduced scan time (in a single breath-hold), a lower x-ray dose. But, it requires very fast and high performance image processing system to reconstruct slice images from spiral scanning. This paper describes the fast image reconstruction techniques with filtered back projection from the viewpoints of fast algorithm as well as hardware implementation for real-time imaging.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.98-105
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• 2010

Fast Fourier Transform is the fast implementation of Discrete Fourier Transform, which deletes periodic operation of DFT. According to the definition, radix-2 FFT can be implemented byre cursive call which divides the input signal points into 2 signal points. Because of its time-consuming stack-copy operation, this recursive method is very slow. To overcome this drawback, butterfly operation with signal rearrangement was devised. Based on the ideas of signal rearrangement and butterfly operation, this paper applies the signal rearrangement method to the Radix-3 FFT and checks the validity of this method.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2421-2433
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• 1997

In this paper, based on the relative logical storage cost of each movie by the difference of service request probability, we propose and implement the SDU(Separate Data Use) method and the EDU(Existing Data Use) method to provide FF(Fast Forward) and FR(Fast Reverse) function in efficiently through analysing MPEG bit stream and frame characteristics. By selecting and applying the FF/FR function providing method based on the service request probability of movie, the proposed method can reduce the cost of FF/FR functions for total serviced movies.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.33-35
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• 1999

인터넷의 발달과 더불어 매일같이 제공되는 수많은 정보로부터 자신에게 필요한 정보만을 추출하는데는 많은 시간과 노력이 소모된다. 이러한 정보수집의 어려움에서 정보를 쉽고 효율적으로 찾기 위해서 웹 문서 시각화 시스템을 구현하였다. 웹 문서 시각화 시스템은 사용자가 검색하는 정보는 과거에 검색했던 웹 문서를 다시 방문하는 경험에서 착안하였다. 이를 위해 인터넷 익스플로러를 통해서 방문 중인 웹 문서의 URL, 키워드, 문서간의 유사성을 추출하여 시각화 한다. 시각화 알고리즘으로 FastMap을 사용하였다. 본 논문에서 FastMap은 웹문서간의 유사성, 즉 상대적인 거리 객체 형태를 2-차원 공간으로 표현하는 알고리즘이다. 2차원 공간으로 매핑된 주변에 있는 웹 문서 객체들을 확대하면 방문중인 웹 문서와 유사성이 있는 문서를 쉽게 찾을 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.468-471
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• 1997

In this paper, we investigate the time-sampling effects on the digital implementation of singular perturbation based STT autopilot with excellent performance and propose a compensation method for the time-sampling effects. In digitization of analog STT autopilot, it is found that the stability margin of the fast dynamics is mostly affected to lead to rapid decrease. Under the this analysis, a composite digital controller with additional compensator for fast dynamics is proposed to improve the time-sampling effect and a simulation verifies the result.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.3
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• pp.103-114
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• 1994

This paper proposes an implementation of DCT (Discrete Cosine Transform) and IDCT (Inverse DCT) using a fast DCT algorithm with shift and addition operations instead of multiplications Based on the proposed algorithm, a new VLSI architecture for the DCT and the IDCT is proposed. It shows modularity , regularity and capability for multiprocessing. Its performance is also simulated by a simulation software, "Compass". The results of the simulation provide the quality of decompression images, the increase in processing speed, representing the superiority of the proposed architecture.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.311-312
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• 2008

This paper try to show that the method for maintaining link stability by fast reporting the status PDU to RLC layer in MAC layer. The proposed method is implemented based on the mechanism of reordering processing in MAC-ehs entity in HSPA evolution system.