• Title/Summary/Keyword: Threshold update

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An Improved VAD Algorithm Employing Speech Enhancement Preprocessing and Threshold Updating (음성 향상 전처리와 문턱값 갱신을 적용한 향상된 음성검출 방법)

  • 이윤창;안상식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.11C
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    • pp.1161-1168
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    • 2003
  • In this paper, we propose an improved statistical model-based voice activity detection algorithm and threshold update method. We first improve signal-to-noise ratio by using speech enhancement preprocessing algorithm combined power subtraction method and matched filter, then apply it to LLR test optimum decision rule for improving the performance even in low SNR conditions. And we propose an adaptive threshold update method that was not concerned in any papers. We also perform extensive computer simulations to demonstrate the performance improvement of the proposed VAD algorithm employing the proposed speech enhancement preprocessing algorithm and adaptive threshold update method under various background noise environments. Finally we verify our results by comparing ITU-T G.729 Annex B.

Implementation of Real Time 3 channel Transmission System Using ECG Data Compression Algorithm by Max-Min Slope Update (최대 및 최소 기울기 갱신에 의한 ECG 압축 알고리듬을 이용한 실시간 3채널 전송시스템 구현)

  • 조진호;김명남
    • Journal of Biomedical Engineering Research
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    • v.16 no.3
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    • pp.271-278
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    • 1995
  • An ECG data compression algorithM using max-min slope update is proposed and a real time 3 channel ECG transmission system is implemented using the proposed algorithm. In order to effectively compress ECG data, we compare a threshold value with the max-min slope difference (MMSD) which is updated at each sample values. If this MMSD value is smaller than the threshold value, then the data is compressed. Conversely, when the MMSD value is larger than threshold value, the data is transmitted after storing the value and the length between the data which is beyond previous threshold level. As a result, it can accurately compress both the region of QRS, P, and T wave that has fast-changing and the region of the base line that slope is changing slow. Therefore, it Is possible to enhance the compression rate and the percent roms difference. In addition, because of the simplicity, this algorithm is more suitable for real-time implementation.

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An Adaptive Dead Reckoning Algorithm using Update Lifetime (유효갱신기간에 기반한 가변 데드레코닝 알고리즘)

  • 유석종;정혜원;최윤철
    • Proceedings of the Korea Multimedia Society Conference
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    • 2000.04a
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    • pp.449-452
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    • 2000
  • This paper proposes a new, adaptive Dead Reckoning model, called Dynamic Dead Reckoning , for Distributed Interactive Simulation and humanoid avatar systems. The proposed model can overcome the weak points of traditional Dead Reckoning caused by a fixed threshold and strong dependency on rotation event. This paper introduces new criteria for update message filtering , named as Update lifetime. The Dynamic Dead Reckoning keeps the balance between extrapolation fidelity and filtering performance by two component models, Variable Threshold Mechanism and Rotation Event model. The experimental results show that the proposed model can lower the increment rate of update traffic to the increase of rotation frequency without any significant loss of accuracy.

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Optimal Mobility Management of PCNs Using Two Types of Cell Residence Time (이동 통신망에 있어서 새로운 셀 체류시간 모형화에 따른 최적 이동성 관리)

  • 홍정식;장인갑;이창훈
    • Journal of the Korean Operations Research and Management Science Society
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    • v.27 no.3
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    • pp.59-74
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    • 2002
  • This study investigates two basic operations of mobility management of PCNs (Personal Communication Networks), i.e., the location update and the paging of the mobile terminal. From the realistic consideration that a user either moves through several cells consecutively or stays in a cell with long time, we model the mobility pattern by introducing two types of CRT (Cell Residence Time). Mobility patterns of the mobile terminal are classified Into various ways by using the ratios of two types of CRT. Cost analysis is performed for distance-based and movement-based location update schemes combined with blanket polling paging and selective paging scheme. It is demonstrated that in a certain condition of mobility pattern and call arrival pattern, 2-state CRT model produces different optimal threshold and so, is more effective than IID ( Independently-Identically-Distributed) CRT model. An analytical model for the new CRT model is compact and easily extendable to the other location update schemes.

Request Distribution for Fairness with a Non-Periodic Load-Update Mechanism for Cyber Foraging Dynamic Applications in Web Server Cluster (웹 서버 클러스터에서 Cyber Foraging 응용을 위한 비주기적 부하 갱신을 통한 부하 분산 기법)

  • Lu, Xiaoyi;Fu, Zhen;Choi, Won-Il;Kang, Jung-Hun;Ok, Min-Hwan;Park, Myong-Soon
    • The KIPS Transactions:PartA
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    • v.14A no.1 s.105
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    • pp.63-72
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    • 2007
  • This paper introduces a load-balancing algorithm focusing on distributing web requests evenly into the web cluster servers. The load-balancing algorithms based on conventional periodic load-information update mechanism are not suitable for dynamic page applications, which are common in Cyber Foraging services, due to the problems caused by periodic synchronized load-information updating and the difficulties of work load estimation caused by embedded executing scripts of dynamic pages. Update-on-Finish algorithm solves this problem by using non-periodic load-update mechanism, and the web switch knows the servers' real load information only after their reporting and then distributes new loads according to the new load-information table, however it results in much communication overhead. Our proposed mechanism improve update-on-finish algorithm by using K-Percents-Finish mechanism and thus largely reduce the communication overhead. Furthermore, we consider the different capabilities of servers with a threshold Ti value and propose a load-balancing algorithm for servers with various capabilities. Simulation results show that the proposed K-Percents-Finish Reporting mechanism can at least reduce 50% communication overhead than update-on-finish approach while sustaining better load balancing performance than periodic mechanisms in related work.

A Link State Update Algorithm based on a Statistical Threshold for Guarantee of Bandwidth (대역폭 보장을 위한 통계적 임계값 기반의 링크 상태 갱신 알고리즘)

  • Lee, Jin-Ju;Chung, Min-Young;Lee, Tae-Jin;Choo, Hyun-Seung
    • Journal of KIISE:Information Networking
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    • v.35 no.5
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    • pp.395-401
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    • 2008
  • In order to determine path(s) satisfied with bandwidth-guaranteed in the Internet, routers should have information on network topology and link state. The information is stored in Link State Database (LSDB) located in each router and managed. If link states information is changed, routers inform their neighbor of link state information changed by sending Link State Update (LSU) messages. However, there is trade-off between reflection of actual link state information on LSDB and cost of sending LSU messages. To find a bandwidth-guaranteed path effectively, it is important to decide whether LSU messages are sent or not for the change of link sate. In this paper, we propose a threshold-based LSU algorithm using statistic to effectively decide for sending LSU messages and evaluates its performance by intensive simulations. Simulation results show that the performance of proposed scheme is superior to the existing LSU schemes.

Contents Adaptive MCTF Using JND (JND를 이용한 적응적 MCTF)

  • Heo, Jae-Seong;Ryu, Chul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.1C
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    • pp.48-55
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    • 2009
  • In scalable video coding, MCTF plays an important role for time-scalability and SNR-scalability. But there is image quality decreasing as MCTF level is increased because time interval of each frame is extended so that is hard to find suitable motion vector. In this paper, we propose an algorithm to prevent image quality from decreasing with unsuitable motion vector during MCTF update process using JND. We adapt JND to find errors within blocks of image and set a threshold which is used to add high frequency components during update process. We can overcome time-gap between frames and achieve better image quality through the proposed algorithm.

CRYPTANALYSIS OF A DYNAMIC THRESHOLD DECRYPTION SCHEME

  • Kim, Ki-Tae;Lim, Seong-An;Yie, Ik-Kwon;Kim, Kyung-Hee
    • Communications of the Korean Mathematical Society
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    • v.24 no.1
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    • pp.153-159
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    • 2009
  • In this paper, we analyze a dynamic threshold decryption scheme proposed by Long et al. It was claimed that the scheme allows to renew the master key, or to add/remove or update a decryption server, without leaking any information on the master key and changing other decryption server's secret keys. We present an attack to Long et al's scheme by using the fact that it renews a decryption server's secret key without changing other decryption server's secret shares.

Clutter Rejection Method using Background Adaptive Threshold Map (배경 적응적 문턱치 맵(Threshold Map)을 이용한 클러터 제거 기법)

  • Kim, Jieun;Yang, Yu Kyung;Lee, Boo Hwan;Kim, Yeon Soo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.2
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    • pp.175-181
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    • 2014
  • In this paper, we propose a robust clutter pre-thresholding method using background adaptive Threshold Map for the clutter rejection in the complex coastal environment. The proposed algorithm is composed of the use of Threshold Map's and method of its calculation. Additionally we also suggest an automatic decision method of Thresold Map's update. Experimental results on some sets of real infrared image sequence show that the proposed method could remove clutters effectively without any loss of detection rate for the aim target and reduce processing time dramatically.

Hybrid Link State Update Algorithm in QoS Routing (하이브리드 QoS 라우팅 링크 상태 갱신 기법)

  • Cho, Kang Hong
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.3
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    • pp.55-62
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    • 2014
  • This paper has proposed Hybrid QoS Routing Link State Update(LSU) Algorithm that has had a both advantage of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. Hybrid LSU algorithm can adapt the threshold based network traffic information and has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and determine the transmission of the message according to update rate per a unit of time. We have evaluated the performance of the proposed algorithm and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm that it can diminish to 10% of the LSU message count.