• The Journal of the Acoustical Society of Korea
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• v.5 no.1
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• pp.17-23
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• 1986

본 논문에서는 FORWARD/BACKWARD 적응 디지털필터를 이용하여 잡음이 섞인 음성의 음질 을 향상하는 방법에 대해 고찰하였다. 이 알고리즘은 음성신호의상관성을 잘 이용하기 위한 현재의 sample을 예측하기 위해 음성신호의 과거 신호뿐만 아니라 미래의 신호도 사용하였다. 이 결과 이 방법 은 백색잡음뿐만 유색잡음의 제거에도 효과적임을 알 수 있었다. 또, 이 방법을 개선한 modified forward/backward 적응 디지털 필터링 방법을 제시하여 성능 향상을 꾀하엿다. 이 개선된 방법은 비교 적 구조가 간단하면서도 여러 종류의 additive noise 에 대해서 잘 동작하며 기존의 방법에 비하여 약 2 유 정도의 개선된 효과를 가져온다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.453-461
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• 2010

This paper presents a branch prediction algorithm and a 4-way set-associative cache for performance improvement of embedded RISC core and a clock-gating algorithm using ODC (Observability Don't Care) operation to improve the power consumption of the core. The branch prediction algorithm has a structure using BTB(Branch Target Buffer) and 4-way set associative cache has lower miss rate than direct-mapped cache. Pseudo-LRU Policy, which is one of the Line Replacement Policies, is used for decreasing the number of bits that store LRU value. The clock gating algorithm reduces dynamic power consumption. As a result of estimation of performance and dynamic power, the performance of the OpenRISC core applied the proposed architecture is improved about 29% and dynamic power of the core using Chartered $0.18{\mu}m$ technology library is reduced by 16%.

• Convergence Security Journal
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• v.6 no.1
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• pp.33-43
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• 2006

RFID System has an advantage that it need not touch an objects for identification of many objects. Because it is working through wireless communication. Also, So many objects can be identified with RFID System at once. However, although RFID System has convenience like above, it has serious privacy concern at the same time. If RFID System is working with an target object through wireless communication, other objects will respond to RFID System signal as well as a target object. Hence, RFID System can be easily exposed user privacy by attacker. In this paper, We propose RFID system authentication model in order to protecting user privacy and traking. Proposed RFID system is operating that not only server authenticate RFID reader but also RFID reader and tag authenticate mutually by using symetric cryptography that operating with tiny and simple processing.

• Convergence Security Journal
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• v.6 no.1
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• pp.55-63
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• 2006

In this paper, an algorithm that provisions absolute differentiation of packet delays is proposed with an objective for enhancing quality of service (QoS) in future packet networks. It features an adaptive scheme that compensates the deviation for prediction on the traffic to be arrived continuously. It predicts the traffic to be arrived at the beginning of a time slot and measures the actual arrived traffic at the end of the time slot, and derives the deviation between the two quantity. The deviation is utilized to the delay control operation for the next time slot to offset it. As it compensates the prediction error continuously, it shows superior adaptability to the bursty traffic as well as the constant rate traffic. It is demonstrated through simulation that the algorithm meets the quantitative delay bounds and shows superiority to the traffic fluctuation in comparison with the conventional mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.664-672
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• 2002

This paper analyzes a sequential estimator with flexible structure for rapid acquisition of the m-sequence signals. If the received PN chips stored in the estimator's internal registers as initial loading values include one error, this chip with error can be corrected through multiple local PN code generators to achieve high-speed acquisition performance. Hamming distance between regenerated local PN codes from the proposed system and received PN code is compared with given threshold to choose a possible correct path and to declare success of the code acquisition. Using signal flow graph, average acquisition time that depends on detection and false alarm probability is calculated. By modifying generally used matched filter structure for PN code acquisition, the proposed system provides flexible structure and rapid acquisition process.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.1-7
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• 2017

Joint Collaborative Team on Video Coding (JCT-VC) of ISO/IEC MPEG and ITU-T developed the HEVC Screen Content Coding (HEVC SCC) standard as the HEVC extension for the screen content video coding. The Intra Block Copy (IBC) is the most effective tool adopted in HEVC SCC and predicts current block from already reconstructed neighboring blocks in the same picture. To reduce the amount of data in BV (Block Vector) to be transmitted, a BV predictor (BVP) is used to generate the BV differences in the IBC BV coding. In this paper, we analyze the current BV prediction process using HEVC reference software SCM-2.0 and SCM-4.0. Based on the analysis results, we propose an improved BVP candidate selection algorithm by adding a search process for adjacent BVs in addition to the existing spatial BVP candidates. Experimental results show that the BD-rate reduction of our proposed improvements ranges from 0.2% to 1%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.175-181
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• 2021

This paper analyzes the artificial intelligence-based approach for short-term energy consumption prediction. In this paper, we employ the reinforcement learning algorithms to improve the limitation of the supervised learning algorithms which usually utilize to the short-term energy consumption prediction technologies. The supervised learning algorithm-based approaches have high complexity because the approaches require contextual information as well as energy consumption data for sufficient performance. We propose a deep reinforcement learning algorithm based on multi-agent to predict energy consumption only with energy consumption data for improving the complexity of data and learning models. The proposed scheme is simulated using public energy consumption data and confirmed the performance. The proposed scheme can predict a similar value to the actual value except for the outlier data.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2750-2752
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• 2003

흑점은 태양 표면에 검은 구멍처럼 보이는 것으로 흑점이 나타나면 태양활동이 활발함을 의미한다. 이러한 태양활동은 플레어나 홍염 등의 형태로 표출되어 지구의 자기장을 변동시킴으로써 전력, 통신 시스템의 장애를 유발하게 된다. 따라서 이러한 흑점 데이터를 예측함으로써 사전에 대비할 수 있도록 할 필요가 있다. 흑점 시계열 데이터의 예측에 사용된 시스템은 병렬구조를 갖는 퍼지시스템(PSFS)으로 각 퍼지시스템의 규칙은 주어진 입출력 데이터를 클러스터링하여 생성하였다. 특히, 흑점 시계열 데이터와 같이 주기성향을 갖는 테이터의 경우에도 적용가능하도륵 유연한 구조를 갖는 개선된 PSFS를 제안하여 그 성능을 검증하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.839-842
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• 2010

In this paper, we propose a residual echo and noise reduction scheme for hands-free telephony applications. The proposed algorithm uses a noise robust modified AP algorithm which estimate well echo path in noisy and whitens residual echo signal using linear prediction at non double-talk duration. It is confirmed that the proposed algorithm shows better performance from acoustic interference cancellation (AIC) viewpoint.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.303-308
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• 1997

전기자동차의 구동장치는 모터, 인버터, 감속기 및 차동기어 등으로 구성되는데 모터는 주로 유도전동기와 영구자석형 동기전동기, 브러쉬리스 전동기 등이 사용되고 있다. 본 연구에서는 이 중에서 가격과 내구성 면에서 이점이 있는 유도전동기를 적용한 전기자동차의 전력시스템의 특성분석과 가속 성능에 대해 다루었다. 축전지, 유도전동기, 인버터로 구성된 전력시스템을 각각 모델링하고, 가속성능 개선을 위해 고속에서의 초대토크 알고리즘과 고전적 방법인 속도에 반비례하도록 자속을 제어하는 방식에 대해 각각 적용하여 차량의 가속성능을 예측, 분석하고 이를 현차시험을 통해 시험결과와 비교 제시하고자 한다. 본 연구에서는 주행 중에 축전지 전압 변동에 따라 유도 전종기의 고속 운전 영역 즉, 약계자 영역에서 전기자동차의 가속 특성이 어떻게 나타나는지를 고찰 하였다.