• Title/Summary/Keyword: component testing

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Reliability Estimation of High Voltage Ceramic Capacitor by Failure Analysis (고압 커패시터의 고장 분석을 통한 신뢰도 예측)

  • Yang, Seok-Jun;Kim, Jin-Woo;Shin, Seung-Woo;Lee, Hee-Jin;Shin, Seung-Hun;Ryu, Dong-Su;Chang, Seog-Weon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.6
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    • pp.618-629
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    • 2001
  • This paper presents a result of failure analysis and reliability evaluation for high voltage ceramic capacitors. The failure modes and failure mechanisms were studied in two ways in order to estimate component life and failure rate. The causes of failure mechanisms for zero resistance phenomena under withstanding voltage test in high voltage ceramic capacitors molded by epoxy resin were studied by establishing an effective root cause failure analysis. Particular emphasis was placed on breakdown phenomena at the ceramic-epoxy interface. The validity of the results in this study was confirmed by the results of accelerated testing. Thermal cycling test for high voltage ceramic capacitor mounted on a magnetron were implemented. Delamination between ceramic and epoxy, which might cause electrical short in underlying circuitry, can occur during curing or thermal cycle. The results can be conveniently used to quickly identify defective lots, determine $B_{10}$ life estimation each lot at the level of inspection, and detect major changes in the vendors processes. Also, the condition for dielectric breakdown was investigated for the estimation of failure rate with load-strength interference model.

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Qualify Characteristics of Yackwa according to the region - Focusing on Jeonbuk Province - (제조지역에 따른 약과의 품질 특성 -전북지역을 중심으로-)

  • Cha, Kyung-Ok
    • Korean Journal of Human Ecology
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    • v.9 no.4
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    • pp.75-81
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    • 2006
  • In this study on the recipe for Yakgwa in Jeonbuk province, a survey of the ingredients, the quantity and the recipe for Yakgwa were conducted by an interview with the notable maker of it in 9 regions ; Jeonju, Imshil, Jangsu, Jeongup, Namwon(Samaemyeon & Dukgwamyeon), Wanju, Gochang, Iksan, away from each other. The hardness testing and the sensory evaluation of Yakgwa were carried out to compare with the control group and Jeonbuk Yakgwa. The results of this study are as follows ; 1. Common ingredients of Yakgwa examined in 9 regions were flour, sesame oil or soybean oil, honey or sugar, ginger juice, alcoholic drinks and etc. The quantity of oil (sesame or soybean) per kilogram of flour was as follows between one-half and one cup of oil, between one and three cups of honey or sugar, between one-half and one cup of ginger juice and between one-half and one cup of alcoholic drinks. Making of Yakgwa in Jeonju and Imshil area, knead flour with the liquid ingredients which are mixed together before. In other areas, after sifting the mixed flour with sesame oil, and then knead the remaining with the sifted. 2. The result of the hardness testing of Yakgwa was that it is higher in this order, Iksan, Imshil, the control group, Jeongup, Jeonju. With while the difference of syrup used in each of them, the result of hardness testing in the same order shows that the component of Yakgwa has more great effect on the hardness than a kind of syrup on which the result by using syrup before&after cooking. And in the sensory evaluation, the surface color of Iksan Yakgwa was the most bright of all, and the shininess was of Imshil and the control group, the cracked level, the softness, the sweet taste and the oily taste of Jeonju Yakgwa was better than other Also, the overall preference, though less meaningful, was same result.

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A Study on the Site Acceptance Test(SAT) Evaluation Algorithm of Energy Storage System using Li-ion Battery (리튬이온전지를 이용한 전기저장장치의 SAT용 성능평가 알고리즘에 관한 연구)

  • Park, Jea-Bum;Kim, Byung-Ki;Kim, Mi-Sung;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.26-37
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    • 2019
  • Recently, standardization of installation progress and technology of site acceptance test(SAT) for energy storage system(ESS) are being required due to performance of ESS depending on working condition and environment even though the quality and safety of each component of ESS is guaranteed. And also, it has been required to perform not only performance testing by H/W equipments but also performance verification by S/W tool, in order to more accurately and reliably validate the performance of the ESS in advanced countries. Therefore, this paper proposes evaluation algorithm for SAT to evaluate performance of ESS and presents modeling of SAT test equipment for ESS by using PSCAD/EMTDC. Furthermore, 30[kW] scaled portable test equipments is implemented based on the proposed algorithm and modeling. From the various simulation and test results, it is confirmed that performance of ESS related to characteristics of capacity and Round-trip efficiency, Duty-cycle efficiency, low voltage ride through(LVRT) and Anti-islanding can be accurately evaluated and that the simulation results of PSCAD/EMTDC are identical to test results of 30[kW] test equipment.

A Study of Hazard Analysis and Monitoring Concepts of Autonomous Vehicles Based on V2V Communication System at Non-signalized Intersections (비신호 교차로 상황에서 V2V 기반 자율주행차의 위험성 분석 및 모니터링 컨셉 연구)

  • Baek, Yun-soek;Shin, Seong-geun;Ahn, Dae-ryong;Lee, Hyuck-kee;Moon, Byoung-joon;Kim, Sung-sub;Cho, Seong-woo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.19 no.6
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    • pp.222-234
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    • 2020
  • Autonomous vehicles are equipped with a wide rage of sensors such as GPS, RADAR, LIDAR, camera, IMU, etc. and are driven by recognizing and judging various transportation systems at intersections in the city. The accident ratio of the intersection of the autonomous vehicles is 88% of all accidents due to the limitation of prediction and judgment of an area outside the sensing distance. Not only research on non-signalized intersection collision avoidance strategies through V2V and V2I is underway, but also research on safe intersection driving in failure situations is underway, but verification and fragments through simple intersection scenarios Only typical V2V failures are presented. In this paper, we analyzed the architecture of the V2V module, analyzed the causal factors for each V2V module, and defined the failure mode. We presented intersection scenarios for various road conditions and traffic volumes. we used the ISO-26262 Part3 Process and performed HARA (Hazard Analysis and Risk Assessment) to analyze the risk of autonomous vehicle based on the simulation. We presented ASIL, which is the result of risk analysis, proposed a monitoring concept for each component of the V2V module, and presented monitoring coverage.

A Study on the Risk Analysis and Fail-safe Verification of Autonomous Vehicles Using V2X Based on Intersection Scenarios (교차로 시나리오 기반 V2X를 활용한 자율주행차량의 위험성 분석 및 고장안전성 검증 연구)

  • Baek, Yunseok;Shin, Seong-Geun;Park, Jong-ki;Lee, Hyuck-Kee;Eom, Sung-wook;Cho, Seong-woo;Shin, Jae-kon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.20 no.6
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    • pp.299-312
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    • 2021
  • Autonomous vehicles using V2X can drive safely information on areas outside the sensor coverage of autonomous vehicles conventional autonomous vehicles. As V2X technology has emerged as a key component of autonomous vehicles, research on V2X security is actively underway research on risk analysis due to failure of V2X communication is insufficient. In this paper, the service scenario and function of autonomous driving system V2X were derived by presenting the intersection scenario of the autonomous vehicle, the malfunction was defined by analyzing the hazard of V2X. he ISO26262 Part3 process was used to analyze the risk of malfunction of autonomous vehicle V2X. In addition, a fault injection scenario was presented to verify the fail-safe of the simulation-based intersection scenario.

Comparison of Principal Component Regression and Nonparametric Multivariate Trend Test for Multivariate Linkage (다변량 형질의 유전연관성에 대한 주성분을 이용한 회귀방법와 다변량 비모수 추세검정법의 비교)

  • Kim, Su-Young;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.21 no.1
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    • pp.19-33
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    • 2008
  • Linear regression method, proposed by Haseman and Elston(1972), for detecting linkage to a quantitative trait of sib pairs is a linkage testing method for a single locus and a single trait. However, multivariate methods for detecting linkage are needed, when information from each of several traits that are affected by the same major gene are available on each individual. Amos et al. (1990) extended the regression method of Haseman and Elston(1972) to incorporate observations of two or more traits by estimating the principal component linear function that results in the strongest correlation between the squared pair differences in the trait measurements and identity by descent at a marker locus. But, it is impossible to control the probability of type I errors with this method at present, since the exact distribution of the statistic that they use is yet unknown. In this paper, we propose a multivariate nonparametric trend test for detecting linkage to multiple traits. We compared with a simulation study the efficiencies of multivariate nonparametric trend test with those of the method developed by Amos et al. (1990) for quantitative traits data. For multivariate nonparametric trend test, the results of the simulation study reveal that the Type I error rates are close to the predetermined significance levels, and have in general high powers.

Development of a Six-Axis Force/Moment Sensor with Rectangular Taper Beams for an Intelligent Robot

  • Kim, Gab-Soon
    • International Journal of Control, Automation, and Systems
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    • v.5 no.4
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    • pp.419-428
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    • 2007
  • This paper describes the development of a six-axis force/moment sensor with rectangular taper beams for an intelligent robot's wrist and ankle. In order to accurately push and pull an object with an intelligent robot's hand, and in order to safely walk with an intelligent robot's foot, the robot's wrist and ankle should measure three forces Fx, Fy, and Fz, and three moments Mx, My, and Mz simultaneously from the mounted six-axis force/moment sensor to the intelligent robot's wrist and ankle. Unfortunately, the developed six-axis force/moment sensor utilized in other industrial fields is not proper for an intelligent robot's wrist and ankle in the size and the rated output of the six-axis force/moment sensor. In this paper, the structure of a six-axis force/moment sensor with rectangular taper beams was newly modeled for an intelligent robot's wrist and ankle, and the sensing elements were designed by using the derived equations, following which the six-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements. Moreover, the characteristic test of the developed sensor was carried out by using the six-component force/moment sensor testing machine. The rated outputs from the derived equations agree well with those from the experiments. The interference error of the sensor is less than 2.87%.

Validity and Reliability of an Instrument for Predictive Nursing Intention for SARS Patient Care (SARS 환자간호 의도예측 도구의 타당도 및 신뢰도 검증 연구)

  • Yoo, Hye Ra;Kwon, Bo Eun;Jang, Yon Soo;Youn, Heun Keung
    • Journal of Korean Academy of Nursing
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    • v.35 no.6
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    • pp.1063-1071
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    • 2005
  • Purpose: This study was done to develop and test validity and reliability of on instrument for predicting nursing intention for SARS patient care. Method: The psychometric properties of a SARS patient care attrition prediction tool, based on the Theory of Planned Behavior, were examined in this study. The Three-phase design involved a) salient beliefs generated from clinical nurses (n=43) b) content validation by expert panel evaluations(n=5) c) face validation by plot testing (n=10) d) and instrument validation in a cross sectional survey (n=299). Psychometric analysis of survey data provided empirical evidence of the construct validity and reliability of the instrument. Result: Principal component analysis verified the hypothesized 6-factor solution, explaining $68.2\%$ of variance, and Alpha coefficients of .7538 to .9389 indicated a high internal consistency of the instrument. Conclusion: The instrument can be used by nurse administrators and researcher to assess clinical nurses' salient beliefs about caring for SARS patients, guide tailored intervention strategies to effective caring, and evaluate the effectiveness of interventions.

Measurement on the Natural Frequency of a Laminated Cantilever Microbeam using a Laser Interferometer (레이저 간섭계를 이용한 적층 마이크로 외팔보의 고유진동수 측정)

  • Kim, Yun-Young;Han, Bong-Koo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.1
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    • pp.17-21
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    • 2018
  • The natural frequency of a laminated cantilever microbeam was studied in the present investigation. The microbeam was made of quartz on a silicon chip, and its top and bottom surfaces were coated with thin(~30nm) gold films. An ultrasonic testing platform was employed to resonate the microbeam, and its time domain signal was optically measured. The natural frequency was quantified through the fast Fourier transform of the waveform, and the result showed good agreement with a theoretical estimation from the classical beam theory. This study is expected to provide a dynamic evaluation technique for micro/nanoscale materials and micromechanical structures.

A Study on Life Prediction of Hydraulic Piston Pump (유압 피스톤 펌프의 수명 예측 연구)

  • Kim, Kyungsoo;Lee, Jihwan;Kang, Myeongcheol;Ryuh, Beomsahng
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.5
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    • pp.607-613
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    • 2018
  • Hydraulic systems are widely used in the field of defense, construction machinery, agricultural machinery, and general industries, due to various advantages such as quick response speed and precision control. The defense equipments such as light rescue vehicle is operated in very harsh environments, so hydraulic components used in defense equipment are required to have very high reliability. In particular, hydraulic piston pump is very important component in a hydraulic systems, so life prediction of pump is essential. Therefore, in this study, we analyze the potential failure and the main failure mode of the hydraulic piston pump for the light rescue vehicle through the FMEA analysis, and predict the life of the pump by the accelerated life test considering the usage conditions.