• Title/Summary/Keyword: 성능 지수

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Performance Analysis of Hybrid CDMA Systems in Impulsive Noise and Nakagami Fading of Wireless Radio Communication (임펄스 잡음과 나카가미 페이딩이 공존하는 무선통신로에서 하이브리드 CDMA 시스템의 성능 해석)

  • 김지웅;강희조;이권현
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.5
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    • pp.1005-1015
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    • 2000
  • In this paper, the performance of Hybrid CDU MFSK system has been analyzed in the environment that narrowband Class-A impulsive noise include Gaussian noise in wireless communication channel and Nakagami fading. The performance of system improved to adopting both of technique MRC diversity and BCH channel coding. The results show that there is substantial degraded in Hybrid CDMA system performance by impulse index is stronger and the fading index is smaller. But also improvement can be obtained when BCH coding techniques are adopted. Additional MRC diversity techniques is more improvement than BCH coding techniques when degraded environment with the low fading index. But BCH coding techniques is more improvement than MRC diversity techniques when fading index has been increased. The Hybrid CDMA MFSK system is incomplete to voice communication standard BER$(10^{-3})$ in Rayleigh fading by independent each adopting techniques BCH coding and MRC diversity. But it's satisfy(improvement can be obtained) to voice communication standard BER in strong impulse noise(24dB over) by adopting techniques BCH coding and MRC diversity at a time. Additional it's a substantial enhancement $(10^{-3})$satisfaction) in fading index (m=3, 22dB) in addition to strong impulse noise and 24dB over with data service standard $(10^{-5})$ BER satisfaction. This result show that there is error performance improved by diversity branch and coding advantage.

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Suggestion of Priority Decision Method for Performance Evaluation Based on Risk Index for Small and Medium Sized Bridges (위험도 지수 기반 중소규모 교량 성능평가 우선순위 결정 방안 제안)

  • Lee, Hee-Hyun;Shin, Byoung-Gil;Lee, Yeong-Il;Kim, Young-Min
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.6
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    • pp.70-76
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    • 2019
  • This paper presents a methodology for priority decision of performance evaluation of small-and-medium-sized highway bridges. This methodology could be used for establishing a maintenance strategy of those bridges which are not liable to the law of the Special Act on the Safety Control and Maintenance of Establishments and are thought laid under blind spot. The risk index are calculated considering vulnerability and social influence, then the bridges are classified as three types, one requiring immediate evaluation, the other one requiring evaluation within next year, and the third one observing, according to the index. The suggested method was applied to a small bridge under service and its field applicability verified. From this study, it was judged that this methodology could be used appropriately for establishing maintenance strategy and saving the maintenance budget.

Waterproofing performance evaluation according to the number of layer for shield TBM segment hydrophilic rubber waterstop (쉴드 TBM 세그먼트 지수재의 배열수 변화에 따른 방수성능 평가)

  • Ham, Soo-Kwon;Jung, Hoon;Kim, Beom-Ju;Jeong, Kyeong-han;Lee, Seok-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.1
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    • pp.47-58
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    • 2020
  • The interest in the use of shield TBM (Tunnel Boring Machine) on the tunnel excavation has been increased rapidly in Korea. The shield TBM tunnel is generally designed as non-drainage tunnel. Consequently, if water leakage through the segment joints happens, big problems on the usage and stability of tunnel can be occurred. In this study, the variation of waterproof capacity of hydrophilic rubber waterstop by the construction error and excessive displacement of segment was studied. In particular, the waterproof capacity of each of single and double layer arrangements of hydrophilic rubber waterstop was examined to verify the efficiency of the double layer arrangement. The test results show that the single layer and double layer hydrophilic rubber waterstop showed the same waterproof performance. hydrophilic rubber waterstop has favorable on the offset, however unfavorable on the gap.

Automated Analysis of fetal Myocardial Performance Index of Doppler Waveform in Normal Pregnancy (정상 태아의 임신 분기별 좌심실 도플러 신호 자동 분석)

  • Kim, Su-min;Ye, Soo-young
    • Journal of the Korean Society of Radiology
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    • v.14 no.6
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    • pp.791-800
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    • 2020
  • Ultrasonography is widely used to evaluate the function of fetal heart, but due to the subjective nature of the test, there are differences in measurement methods for each examiner, and especially the myocardial performance index has no reference index to date. Therefore, in this study, we wanted to analyze pulse Doppler waveforms of normal fetuses and develop an automatic measurement program to make objective measurements. One hundred and thirty-three pregnant women who visited the hospital for prenatal examinations were studied, myocardial performance index was measured after acquiring a pulse doppler image of the left ventricle. As a result, the early, mid and late pregnancy myocardial performance index, measured by the automatic measurement program conducted in this study, was found to increase as pregnancy continued.

Study of Local Performance Index of 2-DOF Parallel Manipulator (2 자유도 병렬형 매니퓰레이터의 지역 성능지수에 관한 연구)

  • Lee, Jong Gyu;Yang, Seung Han;Lee, Sang Ryong;Lee, Choon Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.89-95
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    • 2013
  • This study investigates a parallel manipulator that can move over two parallel sliders and in which the end-effector of the manipulator can be adjusted arbitrarily. Through the direct and inverse kinematics of the manipulator, position equations are derived. These equations represent the relationship between the positions of the sliders and the position of the end-effector. The Jacobian matrices of the direct and inverse kinematics are obtained by these equations. By using the condition number defined from these matrices, the local performance index of the manipulator is proposed. By using the simulation results of the performance index, we find that the manipulator can smoothen movements in only one quadrant and that the distribution of the maximal performance index is affected by the ratio of the length of links and the orientation of the end-effector.

Numerical Performance Analysis of Obstacle Avoidance Method for a Mobile Robot (이동 로봇 장애물 회피 방법의 수치적 성능 분석)

  • Kim, Kwang-Jin;Ko, Nak-Yong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.2
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    • pp.401-407
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    • 2012
  • This paper analyzes performance of major obstacle avoidance methods. For the analysis, numerical performance indexes are proposed: motion distance to goal point, motion time, distance to obstacles, and smoothness of the motion. Especially, the index of smoothness measures efficiency of the motion using the angular acceleration and jerk of the robot heading. Four major obstacle avoidance methods are compared in terms of the performance indexes. The four methods are artificial potential field(APF) method, elastic force(EF) method, APF with virtual distance, and EF with virtual distance. Through simulation, the four methods are compared and features of the methods are explored.

An experimental study for water tightness of segment under high water pressure (고수압 조건에서의 세그먼트 방수성능평가에 대한 실험적 연구)

  • Choo, Seok-Yean;Park, Young-Jin;Kim, Dong-Hyun;Kim, Yong-Il;Lee, Du-Wha;Cho, Sang-Kook
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.5 no.4
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    • pp.361-370
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    • 2003
  • In this study, the performance of water tightness of water expansional sealing material and gasket was evaluated. The water tightness test was performed varying the type of inner pressure condition, for which the water expansional sealing material was inundated for 5 days to evaluate the ability of water tightness. In order to carry out this test, we made use of two types of water expansional sealing material; general type and combined type with non-expansional rubber. In the case of gasket, EPDM gasket and complex gasket sticked to the water expansional sealing material were applied. The performance of water tightness depended on the construction defect and the deformation of segment. The construction defect and segment deformation were generally expressed by gap and offset of the construction joint. The results, of tests showed that the performance of water tightness was largely influenced by the gap between segments. Management criteria of gap and offset were proposed.

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Evaluation of Smoke Risk and Smoke Risk Rating for Combustible Substances from Fire (화재로부터 연소성 물질에 대한 연기위험성 및 연기위험성 등급 평가)

  • Chung, Yeong-Jin;Jin, Eui;You, Ji Sun
    • Applied Chemistry for Engineering
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    • v.32 no.2
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    • pp.197-204
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    • 2021
  • This study investigated the smoke risk assessment of woods and plastics for construction materials, focusing on the smoke performance index-V (SPI-V), smoke growth index-V (SGI-V), and smoke risk index-VI (SRI-VI) according to a newly designed methodology. Spruce, Lauan, polymethylmethacrylate (PMMA), and polycarbonate (PC) were used for test pieces. Smoke characteristics of the materials were measured using a cone calorimeter (ISO 5660-1) equipment. The smoke performance index-V calculated after the combustion reaction was found to be 1.0 to 3.4 based on PMMA. Smoke risk by smoke performance index-V was increased in the order of PC, Spruce, Lauan and PMMA. Lauan and PMMA showed similar values. The smoke growth index-V was found to be 1.0 to 9.2 based on PMMA. Smoke risk by smoke growth index-V increased in the order of PMMA, PC, Spruce, and Lauan. COpeak production rates of all specimens were measured between 0.0021 to 0.0067 g/s. In conclusion, materials with a low smoke performance index-V and a high smoke growth index-V cause a high smoke risk from fire. Therefore, it is understood that the smoke risk from fire is high. It is collectively summarized by the smoke risk index-VI.

Rating Evaluation of Fire Risk for Combustible Materials in Case of Fire (화재 시 연소성 물질에 대한 화재 위험성 등급 평가)

  • Chung, Yeong-Jin;Jin, Eui
    • Applied Chemistry for Engineering
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    • v.32 no.1
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    • pp.75-82
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    • 2021
  • This study investigated the fire risk assessment of woods and plastics for construction materials, focusing on the fire performance index-III (FPI-III), fire growth index-III (FGI-III), and fire risk index-IV (FRI-IV) by a newly designed method. Japanese cedar, red pine, polymethylmethacrylate (PMMA), and polyvinyl chloride (PVC) were used as test pieces. Fire characteristics of the materials were investigated using a cone calorimeter (ISO 5660-1) equipment. The fire performance index-III measured after the combustion reaction was found to be 1.0 to 15.0 with respect to PMMA. Fire risk by fire performance index-III increased in the order of PVC, red pine, Japanese cedar, and PMMA. The fire growth index-III was found to be 0.5 to 3.3 based on PMMA. Fire risk by fire growth index-III increased in the order of PVC, PMMA, red pine, and Japanese cedar. COpeak concentrations of all specimens were measured between 106 and 570 ppm. In conclusion, it is understood that Japanese cedar with a low bulk density and PMMA containing a large amount of volatile organic substances have a low fire performance index-III and high fire growth index-III, and thus have high fire risk due to fire. This was consistent with the fire risk index-IV.

훈춘 토양 자원 평가와 개발이용

  • 류충걸
    • Proceedings of the Speleological Society Conference
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    • 1992.07a
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    • pp.42-42
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    • 1992
  • 본 논문에서 훈춘 농업개발을 위하여 농업생산의 기본 자료인 토양자원에 대하여 평가하고 개발 이용에 대한 평가 방법은 여러 가지가 있지만 본 논문에서는 지수-등급법을 사용하여 훈춘시 토양자원의 등급을 확정했다. 지수 항목에서는 일반적으로 통용하는 항목 외에 적산온도, 토양생산성능을 증설했고 지수 설정에서는 부동한 항목에 대하여 부동한 지수를 주였다. 토양자원의 등급획분에서는 계산한 지수의 대소에 따라 4등 6급으로. 나누어 토양의 비옥성과 작물배치의 적합성을 종합적으로 개괄했고 토양 이용 방향에 대해 제시했다.(중략)

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