• Title/Summary/Keyword: Dynamic threshold

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Performance Evaluation of Gang Scheduling Policies with Migration in a Grid System

  • Ro, Cheul-Woo;Cao, Yang
    • International Journal of Contents
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    • v.6 no.4
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    • pp.30-34
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    • 2010
  • Effective job scheduling scheme is a crucial part of complex heterogeneous distributed systems. Gang scheduling is a scheduling algorithm for grid systems that schedules related grid jobs to run simultaneously on servers in different local sites. In this paper, we address grid jobs (gangs) schedule modeling using Stochastic reward nets (SRNs), which is concerned for static and dynamic scheduling policies. SRN is an extension of Stochastic Petri Net (SPN) and provides compact modeling facilities for system analysis. Threshold queue is adopted to smooth the variations of performance measures. System throughput and response time are compared and analyzed by giving reward measures in SRNs.

A Study on Character Extraction in Vehicle Number Plate and Character Recognition (자동차 번호판 영역의 문자추출과 인식에 관한 연구)

  • 김도형;이선화;김미숙;차의영
    • Proceedings of the Korean Information Science Society Conference
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    • 2000.10b
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    • pp.338-340
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    • 2000
  • 자동차 번호판 인식 시스템은 영상획득, 번호판 영역 추출, 추출된 번호판 영역의 전처리, 문자부분 영역화, 문자인식 등의 5가지 핵심부분으로 구성된다. 그 중에서도 번호판 영역 추출, 추출된 영역의 전처리, 문자부분 영역화의 정확성은 전체 시스템 인식률에 지대한 영향을 줄 수 있는 부분으로써 그 정확성이 요구된다. 이에 본 논문에서는 컴퓨터 비젼 분야 중의 하나인 영상처리 기법을 사용하여 명암의 변화에도 문자를 잘 추출할 수 있는 Dynamic Adaptive Threshold 방법을 사용하여 추출된 번호판 영역을 이진화하고, 정확하게 문자 부분을 영역화하기 위한 방법으로 누적분포와 번호판 문자배열 특성을 이용한 방법을 제안한다. 그리고 추출되어진 문자는 ART2 신경망을 이용하여 인식한다.

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상하분해 단체법에서 수정 Forrest-Tomlin 방법의 효율적인 구현

  • 김우제;임성묵;박순달
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1998.10a
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    • pp.63-66
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    • 1998
  • In the implementation of the simplex method program, the representation and the maintenance of basis matrix is very important, In the experimental study, we investigates Suhl's idea in the LU factorization and LU update of basis matrix. First, the triangularization of basis matrix is implemented and its efficiency is shown. Second, various technique in the dynamic Markowitz's ordering and threshold pivoting are presented. Third, modified Forrest-Tomlin LU update method exploiting sparsity is presented. Fourth, as a storage scheme of LU factors, Gustavson data structure is explained. Fifth, efficient timing of reinversion is developed. Finally, we show that modified Forrest-Tomlin method with Gustavson data structure is superior more than 30% to the Reid method with linked list data structure.

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Analysis of Headspace Volatile Compounds in Cold-stored and Freeze-dried Krill Eupausia superba

  • Park, Jin-Yong;Kim, Ye-Joo;Lee, Yang-Bong
    • Fisheries and Aquatic Sciences
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    • v.17 no.2
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    • pp.189-195
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    • 2014
  • Headspace volatile compounds of cold-stored and freeze-dried Krill Eupausia superba were analyzed to investigate their flavor qualities using a system combining a dynamic headspace isolator, an automatic thermal desorber, and a gas chromatograph-mass-selective detector. Levels of oxidation products of polyunsaturated fatty acids such as aldehydes, alcohols, and ketones, which are known to give seafood a nasty smell because of their low flavor threshold values, increased during cold storage of krill. Notably, levels of 2-methylpropanal, 3-methylbutanal, 2-methylbutanal and 2-butanone increased during its storage. They can be considered index compounds of off-odor according to freshness degradation during storage. By contrast, in freeze-dried krill powder, levels of aldehydes, ketones, and aromatic compounds decreased rapidly. Only alcohols, which did not greatly affect the food flavor, were isolated in large amounts. It was confirmed that levels of oxidized compounds of krill increased during cold storage, but decreased in freeze-dried krill.

A Statistical Approach to Analysis of Saccadic Eye Movements (Saccadic 안구운동 해석에 대한 통계학적인 접근)

  • Kim, Nam-Gyun;Kim, Bu-Gil
    • Journal of Biomedical Engineering Research
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    • v.10 no.3
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    • pp.289-292
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    • 1989
  • In this study we propose an approach based on statistical method which use the whole of saccades instead of using a few points of saccades in the quantitative analyse saccades. We computed statistical parameters such as mean velocity, quadratic mean velocity, standard duration, skewness of saccades velocity, flattness factor of saccades velocity, and mean delay by considering eye velocity as a probability density function. The results abtained are the following as ; This parameters showed the same trend like that of the main sequence. They were not biased by the systematic errors due to the arbitrary threshold. They were also less sensitive to noise, which was tested through the model simulation. So they are expected to provide a more comprehensive quantitative description of the dynamic properties of saccade in the diagnostic field.

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Operation Policy for Enhancing Availability of a Web Server against DoS Attacks (서비스 거부 공격에 대응한 웹서버 가용성 향상을 위한 운용 정책 방안)

  • Baik, Nam-Kyun;Jung, Sou-Hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.8B
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    • pp.735-744
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    • 2008
  • This paper proposes a 'secure node' to be robust against network-based DoS attacks. The secure node selectively accepts new sessions based on the Zipf's law while a link is in the overload state. Our scheme calculates a threshold value for overload state, and provides a dynamic service mechanism for enhancing availability of a web server. The simulation results show performance improvement of the proposed scheme in terms of completion/connection ratios.

Characteristics of CMOS Transistor using Dual Poly-metal(W/WNx/Poly-Si) Gate Electrode (쌍극 폴리-금속 게이트를 적용한 CMOS 트랜지스터의 특성)

  • 장성근
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.3
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    • pp.233-237
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    • 2002
  • A giga-bit DRAM(dynamic random access memory) technology with W/WNx/poly-Si dual gate electrode is presented in 7his papers. We fabricated $0.16\mu\textrm{m}$ CMOS using this technology and succeeded in suppressing short-channel effects. The saturation current of nMOS and surface-channel pMOS(SC-pMOS) with a $0.16\mu\textrm{m}$ gate was observed 330 $\mu\A/\mu\textrm{m}$ and 100 $\mu\A/\mu\textrm{m}$ respectively. The lower salutation current of SC-pMOS is due to the p-doped poly gate depletion. SC-pMOS shows good DIBL(dram-induced harrier lowering) and sub-threshold characteristics, and there was no boron penetration.

Efficient Multi-Touch Detection Algorithm for Large Touch Screen Panels

  • Mohamed, Mohamed G.A.;Cho, Tae-Won;Kim, HyungWon
    • IEIE Transactions on Smart Processing and Computing
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    • v.3 no.4
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    • pp.246-250
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    • 2014
  • Large mutual capacitance touch screen panels (TSP) are susceptible to display and ambient noise. This paper presents a multi-touch detection algorithm using an efficient noise compensation technique for large mutual capacitance TSPs. The sources of noise are presented and analyzed. The algorithm includes the steps to overcome each source of noise. The algorithm begins with a calibration technique to overcome the TSP mutual capacitance variation. The algorithm also overcomes the shadow effect of a hand close to TSP and mutual capacitance variation by dynamic threshold calculations. Time and space filters are also used to filter out ambient noise. The experimental results were used to determine the system parameters to achieve the best performance.

In-situ TEM of Carbon Nanotube Field Emitters and Improvement of Electron Emission from Nanotube Films by Laser Treatment

  • Saito, Yahachi;Seko, Kazuyuki;Kinoshita, Jun-ichi;Ishida, Toshiyuki;Yotani, Junko;Kurachi, Hiroyuki;Uemura, Sashiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1081-1086
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    • 2005
  • Dynamic behavior of carbon nanotubes (CNTs) in an electric field is directly observed by in-situ transmission electron microscopy (TEM). The CNT field emitters examined by in-situ TEM are multiwalled, double-walled and single walled CNTs. Threshold fields for electron emission and sustainable emission currents depending on the structure of CNTs are presented, and degradation mechanism of the CNT field emitters is discussed. In addition to the microscopy studies on individual CNTs, our recent development in surface treatment of CNT layers grown by chemical vapor deposition, which brings about high density of emission current and high uniformity, is also presented.

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Tailoring the Static Characteristics of Implanted VCSELs with the Implant and Metal Aperture Radii (임플랜트 및 금속전극 반경에 따른 임플랜트 VCSEL 정특성의 변화)

  • Kim, Tae-Yong;Kim, Sang-Bae;Park, Bun-Jae;Son, Jeong-Hwan
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.7
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    • pp.37-41
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    • 2004
  • We have formulated an empirical analytic model for the static characteristics of implanted vertical-cavity surface-emitting lasers (VCSELs). Specifically, we have derived analytic formulas for the threshold current, slope efficiency, dynamic resistance, and the output power and forward voltage at the operation current of 12 ㎃ in terms of the implant and metal-aperture radii by fitting the measured results. The radii of the metal aperture and implant mask of the 850 nm VCSELs range from 4 to 12.5 ${\mu}{\textrm}{m}$ and 7 to 17.5 ${\mu}{\textrm}{m}$ respectively. The model shows the way of tailoring the VCSEL characteristics by changing the mask dimensions only.