• Annual Conference of KIPS
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• 2023.05a
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• pp.76-77
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• 2023

가상 화폐가 금융권에 등장한 이후 가상화폐를 얻기 위한 채굴이라는 작업이 각광받기 시작하였다. 하지만 시간이 흐르면서 채굴기를 가동하는데 소모되는 전력보다 채굴에 따른 보상의 양이 적어지면서 수익 구조가 무너지기 시작하였다. 본 논문에서는 태양열 에너지 발전을 통해 가상화폐를 채굴하는 방법을 제안한다. 태양열 발전을 위한 시스템을 설계하고 수익성을 증명하였다. 그 결과 태양열 발전 설비로 생산한 전력을 판매하여 얻는 수익보다 채굴기를 가동하여 얻는 수익이 약 17% 더 많은 것을 알 수 있었다. 채굴 시장의 규모는 블록체인 시장 규모에 비례하여 증가하고 있기 때문에 채굴 시장의 전망도 증가할 것으로 예상된다.

• Annual Conference of KIPS
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• 2023.05a
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• pp.119-122
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• 2023

양자 컴퓨터가 현대 암호 시스템의 보안성을 위협하고 있음에 따라, 최근 잠재적인 양자 공격들에 대한 분석 연구들이 다수 발표되고 있다. 공개키 암호인 RSA와 ECC의 경우, Shor 알고리즘에 의해 다항시간 내에 해결됨으로써 보안성이 완전히 붕괴되는 반면, 대칭키 암호는 Grover 알고리즘에 의해 보안 강도가 제곱근으로 감소하기 때문에 키 길이를 증가시킴으로써 기존 보안성을 복구할 수 있다. 이론적으로 Grover 알고리즘은 보안성을 훼손시키지만, 현실적인 공격 난이도가 매우 높음에 따라 대상 암호에 대한 양자 회로 최적화 구현이 중요하다. 이에 본 논문에서는 블록암호 RC5를 양자 회로 상에서 최적화하고 이를 기반으로 Grover 공격 비용을 추정한다. 마지막으로, 추정한 비용을 NIST의 양자 후 보안 강도 평가와 함께 비교함으로써 RC5에 대한 양자 암호 분석을 수행한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.126-135
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• 2014

The Euclidean distance between error probability density functions (EDEP) has been used as a performance criterion for supervised adaptive signal processing in impulsive noise environments. One of the drawbacks of the EDEP algorithm is a heavy computational complexity due to the double summation operations at each iteration time. In this paper, a recursive method to reduce its computational burden in the estimation of the EDEP and its gradient is proposed. For the data block size N, the computational complexity for the estimation of the EDEP and its gradient can be reduced to O(N) by the proposed method, while the conventional estimation method has $O(N^2)$. In the performance test, the proposed EDEP and its gradient estimation yield the same estimation results in the steady state as the conventional block-processing method. The simulation results indicates that the proposed method can be effective in practical adaptive signal processing.

• Journal of Korea Game Society
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• v.9 no.4
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• pp.89-96
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• 2009

In general, the size of volume data is large since it has logical 3D structure so it takes long time to manipulate. Much work has been done to improve processing speed of volume data. In this paper, we propose a interlaced scanning volume rendering that reduce computation time by using temporal coherence with minimum loss of image quality. It renders a current frame by reusing information of previous frame. Conventional volume raycasting renders each frame by casting rays on every pixels. On the other hand, our methods divided an image into n-pixel blocks, then it casts a ray on a pixel of a block per each frames. Consequently, it generates an image by accumulating pixel values of previous n frames. The quality of rendered image of our method is better than that of simple screen space subsampling method since it uses afterimage effect of human cognitive system, and it is n-times faster that the previous one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.67-74
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• 2009

This paper presents a method of improving the service availability by distributing the traffic of voice/data calls over the multi-layer cells in a mobile communication network. The traffic model is described and the call handling performance is analyzed. In our method, a fast moving call is moved to and serviced in the upper layer cell. A call is also moved upward when an overflow occurs. But unlike other methods, the call that is moved upward in the overflow case is the one which has the longest sojourn time in the cell. Moreover, when the call that was moved upward due to overflow condition stays longer than a certain period of time in the upper layer cell, the system moves the call back to the lower layer in order to save the more expensive resources of the upper layer cell. Call handling performance of this method evaluated from M/M/C/K models shows clear improvement with respect to call blocking probability and forced termination probability.

• The KIPS Transactions:PartB
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• v.16B no.6
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• pp.463-470
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• 2009

In this paper, we propose the advanced fire-flame detection algorithm using camera image for better performance than previous sensors-based systems which is limited on small area. Also, previous works using camera image were depend on a lot of heuristic thresholds or required an additional computation time. To solve these problems, we use statistical values and divide image into blocks to reduce the processing time. First, from the captured image, candidate flame regions are detected by a background model and fire colored models of the fire-flame. After the probability models are formed using the change of luminance, wavelet transform and the change of motion on time axis, they are used for membership function of fuzzy logic. Finally, the result function is made by the defuzzification, and the probability value of fire-flame is estimated. The proposed system has shown better performance when it compared to Toreyin's method which perform well among existing algorithms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.231-238
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• 2004

This paper presents the high speed noise reduction processing system using the modified discrete fourier transform(MDFT) on the frequency domain. The proposed filter uses the linear prediction coefficients of the adaptive line enhance(ALE) method based on the Sign algorithm The signals with a random noise tracking performance are examined through computer simulations. It is confirmed that the fast adaptive digital filter is realized by the high speed adaptive noise reduction(HANR) algorithm with rapid convergence on the frequency domain(FD).

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3175-3184
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• 1997

To support large storage capacity and real-time characteristics of continuous media storage systems, we need to improve the performance of disk I/O subsystems. To improve the performance, we exploited buffer sharing scheme that reduces the number of disk I/Os. We utilized the advance knowledge of continuous media streams that is used to anticipate data demands, and so Promoting the sharing of blocks in buffers. In this paper, we proposed a buffer replacement algorithm that enables subsequent users requesting the same data to share buffer efficiently. The proposed algorithm manages buffers by utilizing reference interval information of blocks. In order to verify validity of the proposed algorithm, we accomplished simulation experiments and showed the results of performance improvements compared to traditional buffer replacement algorithms.

• Annual Conference of KIPS
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• 2009.04a
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• pp.913-915
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• 2009

디지털 영상 기술의 발전과 고속 인터넷의 성장은 고화질의 영상을 녹화하고 사용자간 영상 공유를 빠르게 할 수 있는 환경을 제공하였다. 일반적으로 녹화된 영상을 공유하기 이전에 불필요한 부분을 삭제하기 위해 동영상 편집 과정을 거치게 된다. 하지만 대용량의 영상을 편집한 뒤, 저장하는데 많은 시간이 소모된다. 이런 문제를 해결하기 위해 기존 연구 FWAE[1]에서는 내용 수정이 이루어지지 않는 영상 편집의 특징을 고려하여, 편집저장에서 가장 큰 시간을 차지하는 데이터 복사 과정을 데이터 블록 공유로 대체하는 고속 편집저장 기법을 제시했다. 하지만 제안 기법에서는 압축 영상에 대한 특징을 고려하지 않아 일부 프레임이 유실될 수 있는 문제가 있었다. 이에 본 논문에서는 압축 코덱으로 널리 사용되는 MPEG을 분석하여, FWAE 고속 편집저장에서 프레임 유실을 방지할 수 있는 개선 기법을 제안한다.

• Journal of IKEEE
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• v.17 no.4
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• pp.570-578
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• 2013

This paper proposed an $8{\times}8$ HEVC inverse core transform architecture reusing multipliers. In HEVC core transform, processing of lower size block is identical with even part of upper size block. So an $8{\times}8$ core transform architecture can process both $8{\times}8$ and $4{\times}4$ core transforms. However, when $8{\times}8$ core transform architecture is exploited, frame processing time doubles in $4{\times}4$ core transform, since $8{\times}8$ and $4{\times}4$ core transforms concurrently process 8 and 4 pixels, respectively. In this paper, a novel inverse core transform architecture is proposed based on multiplier reuse. It runs as an $8{\times}8$ inverse core transformer or two $4{\times}4$ inverse core transformer. Its frame processing time is same in $8{\times}8$ and $4{\times}4$ core transforms, and reduces gate counts by 12%.