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A study on the overload control of the ATM switching system (ATM 교환기 과부하제어 연구)

  • 기장근;최진규;김영선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.4
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    • pp.952-960
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    • 1996
  • In this paper, a new overload control scheme is proposed for a control system in ATM switching system. The proposed control scheme includes a counter that conunts the number of accepted calls and is decreased at cach D time interval. In overload condition of call processor, the control scheme detects over load condition when the counter value reaches a certain threshold value. Under overload condition, processor utilization is measured and the value of the D is updataed according to the difference between measured processor utilization and target utilization. A new call is accepted accepted only if the value of the counter is less than the threshold value. In overflow condition of cell traffic, accept probability of new call is reduced exponetially according to the elapsed time. The results of simulation show that the proposed overload contorl scheme maintains the target utilization very well under the various processor overload conditions and reduces the cell loss probability under the cell overflow conditions.

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A Study on the Trial Results and Performance Trend of Diesel Main Engine (디젤 주기관의 시운전 결과 및 성능 변화 추이에 관한 연구)

  • Cho, Kwon-Hae;Lee, Dong-Hoon;Son, Min-Su
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.73-74
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    • 2005
  • Shipping company and operators have to manage well to keep shipping schedules without problems in main engine. Specially operators have to operate main engine within the limit of operation point, and adjust related parameters to be operated safely and continuously. Also operators have ability to analyze fouling condition of hull through comparing data gotten from P-V curve and performance results of new building ships in trial with service ships. In this study, not only compared main engine performance results in shop trial and sea trial, but also investigated performance trend in accordance with the time elapsed for the service ship's diesel engine. They were confirmed as follows. First, shop trial load is higher than sea trial load but ship's speed is satisfied with owner's contract speed. Second as time goes by, load of service ship increases steadily and other parameters related with main engine shows variable change depend on main engine load increasing.

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The Behavior of Undrained Pore Water Pressure in Normally Consolidated and Saturated Clay(II) - Visco Elastic Analysis Model - (포화된 정규압밀 점성토에서 비배수 공극수압의 거동(II) - 점탄성 해석 모델 -)

  • 임성훈
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.4
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    • pp.137-143
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    • 2003
  • The initial condition of $\Delta \sigma_3 \;=\; \Delta u$ is used for analyzing the time dependent behavior of ground. This is based on the concept that the coefficient of pore water B is the unity on the condition of saturation. but some measured consolidation data in the field showed that the pore water pressure was not dissipated as time elapsed but it was maintained constant value or it's dissipation rate was slower than that of the predicted. and so the measured data of pore water pressure was not consistent with that of settlement. In this study, the rheological model for the pore water pressure behavior on undrained condition was induced and compared with the experiment data of the literature. The result showed that the suggested model was consistent well with the result of experiment, but the suggested model could not explain the effect of the decrease of void ratio according to consolidation.

EXPERIMENTAL STUDY ON SEALING QUALITY OF POLYCARBOXYLATE CEMENT USED AS ROOT CANAL SEALER (카복실레이트 세멘트를 근관(根管) 충전재(充塡材)로 사용(使用) 시(時) 근관(根管) 폐쇄성(閉鏁性)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Hwang, Young-Hwan
    • Restorative Dentistry and Endodontics
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    • v.2 no.1
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    • pp.32-37
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    • 1976
  • The author has studied comparatively the sealing quality of polycarboxylate cement, one of the newest dental cement systems, and zinc oxide eugenol cement by means of penetration of 2% methylene blue solution through the root apex of human teeth in 72 cases as time elapsed. Followings are the results obtained from this study. 1) In all groups, there was no increase in penetration related to increased time of immersion in the dye. 2) In polycarboxylate cement groups, there was a significant difference in depth of dye penetration of each tooth, but in zinc oxide eugenol cement group, there was a slight difference. 3) The depth of dye penetration of zinc oxide eugenol cement group is slightly lower than that of poly carboxylate cement groups. 4) In polycarboxylate cement groups, Carbolit cement group showed comparatively lower grade of dye penetration than Carbo cement group.

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HPLC Detection of Free Malonaldehyde for Rapid Measurement of Lipid Oxidation Development

  • Key Whang;Kim, Chang-Min
    • Preventive Nutrition and Food Science
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    • v.5 no.1
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    • pp.7-9
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    • 2000
  • Variouss concentrationss of free malonaldehyde were prepared from 1,1,3,3-tetraethoxy propane (TEP). Spectrophoto-metric determination and HPLC analysis of free malonaldehyde instead of malonaldehyde-thiobaribituric acid (MA-TBA) complex were conducted. Malonaldehyde was well separated on a $\mu$Bondapak C18 column. The absorbances at 254 nm and the HPLC peak areas of free malonaldehyde increased with the increase in its concentration. The correlation coefficient between absorbances and peak areas was 0.998. The total time elapsed to conduct the whole procedure was less than 15 minutes. This method directly measured the amount of free malonaldehyde in a short period of time successfully. This procedure is expected to be used as a rapid, accurate and specific means to de-termine the development of lipid oxidation in food.

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A Compressive Strength and Mixing Properties of Lightweight Porous Block Using Lightweight Aggregate by Variation of Manufacture Time (인공경량골재 사용 경량투수블록의 제조시간 변화에 따른 배합 및 압축강도 특성)

  • Kim, Young-Uk;Lee, Kyung-Su;Oh, Tea-Gue;Jeong, Su-Bin;Ban, Jun-Mo;Choi, Se-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.118-119
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    • 2018
  • The purpose of this study is to investigate the compressive strength and mixing properties of the lightweight block, which has been manufactured without the pre-wetting process, in the lightweight block using domestic artificial lightweight aggregate. The test results of the specimens produced within 30 minutes after the preparation showed high compressive strength but poor permeability. Therefore, the elapsed time after the manufacture, which is expected to have required compressive strength and permeability, was about 60 minutes in this study.

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Finite Element Analysis on Contact and Work Stress of Rolled Strip (압연되는 스트립의 접촉 및 가공 응력에 대한 유한 요소 해석)

  • Cho, Jae-Ung;Han, Moon-Sik
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.23-29
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    • 2008
  • This study analyzes the rolled circular rod strip with radius of loom and length of 350cm by using finite element analysis. The material strength and its durability of the rolled strip can be predicted through this study. As the penetration tolerance by contact decreases, the contact rigidity of strip increases. As the contact rigidity becomes the highest at the elapsed time of 1.2 second, the contact stress becomes the lowest. On the contrary, von-Mises stress becomes highest at this time. The total deformation on strip increases from the upper part of strip at the position near to rotating roll to the lower part of strip at the position near to fixing roll.

A Study on the Characteristics of Discharge Capacity for Horizontal Drains (수평배수재의 통수특성에 관한 연구)

  • 박정용;박정순;장연수;김수삼
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.557-564
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    • 2002
  • Discharge capacity test is carried out to find out influencing factors on discharge capacity of prefabricated horizontal drains to improve weak dredged clay. Four representative prefabricated horizontal drains are selected based on the size of drain as well as the shape of core. Test is carried out for 10 days at each three level of confining pressure for all drains. Effects of elapsed time, confining pressure, hydraulic gradient and strength of filter and core on discharge capacities are examined. It is found that discharge capacity of drain, which has deformable core or has a possibility of squeezing filter into core, decreases more with time due to its low strength. As confining pressure increases, discharge capacity decreases due to the squeezing of filter into core.

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Implementation of GA Processor with Multiple Operators, Based on Subpopulation Architecture (분할구조 기반의 다기능 연산 유전자 알고리즘 프로세서의 구현)

  • Cho Min-Sok;Chung Duck-Jin
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.5
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    • pp.295-304
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    • 2003
  • In this paper, we proposed a hardware-oriented Genetic Algorithm Processor(GAP) based on subpopulation architecture for high-performance convergence and reducing computation time. The proposed architecture was applied to enhancing population diversity for correspondence to premature convergence. In addition, the crossover operator selection and linear ranking subpop selection were newly employed for efficient exploration. As stochastic search space selection through linear ranking and suitable genetic operator selection with respect to the convergence state of each subpopulation was used, the elapsed time of searching optimal solution was shortened. In the experiments, the computation speed was increased by over $10\%$ compared to survival-based GA and Modified-tournament GA. Especially, increased by over $20\%$ in the multi-modal function. The proposed Subpop GA processor was implemented on FPGA device APEX EP20K600EBC652-3 of AGENT 2000 design kit.

Study on Salt-Proof Characteristics of Copper Clad Aluminum (동복알루미늄의 내염특성 연구)

  • Kim, Jin-Sa;Bae, Duck-Kweon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.9
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    • pp.1764-1768
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    • 2009
  • As the demand of electric power is increasing rapidly, the need of the compact and light electric power device is also increased. Copper clad aluminum (CCA) is newly proposed electrical conductor, because of its light-weight and low-cost characteristics, to replace the existing conductor made of copper. This paper presents the salt-proof characteristics of the copper clad aluminum (CCA) to certificate long time safe operation of the newly proposed electrical conductor. The two types of the CCA conductor were tested in the neutral salt spray tester. The experimental results of two types of the CCA with salt spray were presented in this paper. The results comprise resistance measured data, micro picture of the selected surface, and component measured data according to the elapsed time. The period of the experiment was 1,000 hours. There was no evidence to show the corrosion of CCA during the whole period of the experiments.