• Title/Summary/Keyword: Life testing

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Proficiency testing of cadmium and lead in polypropylene resin (폴리프로필렌 수지 중 카드뮴과 납 측정 숙련도시험)

  • Cho, K.H.;Lim, M.C.;Min, H.S.;Han, M.S.;Song, H.J.;Park, C.J.
    • Analytical Science and Technology
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    • v.20 no.3
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    • pp.183-192
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    • 2007
  • The various environmental regulation directives such as RoHS (restriction of hazardous substances in electrical and electronic products) and WEEE (waste from electrical and electronic equipments) are practically used as the technical barrier in international trade (TBT) of vehicles and electrical and electronic products recently. Regarding such an environmental regulation, Korea Research Institute of Standards Science (KRISS) organized a proficiency testing scheme to establish the reliability of measurement results produced by the relevant research institutes and test laboratories in Korea. Participants were 31 laboratories related to production of the electrical and electronic equipments and mobile vehicles. Two polypropylene samples of pellet type were employed as the proficiency testing materials (PTMs). Cadmium and lead were the analytes chosen among six components regulated in European Union (EU) RoHS directive. The PTMs were sent to the participants by post on September $1^{st}$ 2006, and deadline for results submission were October $10^{th}$ 2006. The results of each laboratory were evaluated in comparison with KRISS reference values using Robustic Z-score and Youden plot methods. The results of the various sample digestion methods were also compared. Most of participants reported good agreement within 10 % range of reference values. However, results from several laboratories showed significant biases from reference values. These laboratories should establish the quality assurance system for improvement of the measurement reliability.

Image Enhancement for Sub-Harmonic Phased Array by Removing Surface Wave Interference with Spatial Frequency Filter

  • Park, Choon-Su;Kim, Jun-Woo;Cho, Seung Hyun;Seo, Dae-Cheol
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.3
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    • pp.211-219
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    • 2014
  • Closed cracks are difficult to detect using conventional ultrasonic testing because most incident ultrasound passes completely through these cracks. Nonlinear ultrasound inspection using sub-harmonic frequencies a promising method for detecting closed cracks. To implement this method, a sub-harmonic phased array (PA) is proposed to visualize the length of closed cracks in solids. A sub-harmonic PA generally consists of a single transmitter and an array receiver, which detects sub-harmonic waves generated from closed cracks. The PA images are obtained using the total focusing method (TFM), which (with a transmitter and receiving array) employs a full matrix in the observation region to achieve fine image resolution. In particular, the receiving signals are measured using a laser Doppler vibrometer (LDV) to collect PA images for both fundamental and sub-harmonic frequencies. Oblique incidence, which is used to boost sub-harmonic generation, inevitably produces various surface waves that contaminate the signals measured in the receiving transducer. Surface wave interference often degrades PA images severely, and it becomes difficult to read the closed crack's position from the images. Various methods to prevent or eliminate this interference are possible. In particular, enhancing images with signal processing could be a highly cost-effective method. Because periodic patterns distributed in a PA image are the most frequent interference induced by surface waves, spatial frequency filtering is applicable for removing these waves. Experiments clearly demonstrate that the spatial frequency filter improves PA images.

Durability Performance Evaluation of an Aluminum Knuckle using Virtual Testing Method (가상시험법을 이용한 알루미늄 너클의 내구수명 평가)

  • Ko, Han-Young;Choi, Gyoo-Jae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.1
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    • pp.44-50
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    • 2010
  • Durability performance evaluation technology using Virtual Testing Method is a new concept of a vehicle design, which can reduce the automotive components design period and cost. In this paper, the fatigue life of an aluminum knuckle of a passenger car is evaluated using virtual testing method. The flexible multibody dynamic model of a front half car module is generated and solved with service loads which are measured from Belgian roads. Using a multibody dynamic analysis software, the flexible multibody dynamic simulation of a half car model is carried out and the dynamic stress profile of an aluminum knuckle is acquired. The stress profile is exported to a fatigue analysis software and durability performance of an aluminum knuckle is evaluated.

Optimal Release Time for Software Considering Distribution of Periodic Service Packs and Uncertain Patches during Operational Phase (사용단계에서 주기적 서비스 팩 배포와 불확실한 패치 배포를 고려한 소프트웨어의 최적 출시시기)

  • Park, Il Gwang;Kong, Myung Bock
    • Journal of Korean Institute of Industrial Engineers
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    • v.33 no.4
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    • pp.487-493
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    • 2007
  • In this paper, we deal with an optimal software-release problem of determining the time to stop testing and release the software system to the user. The optimal release time problem is considered from maintenance like the periodic distribution of service packs and the unpredictable distribution of patches after the release. Moreover, the environment of software error-detection during operation differs from the environment during testing. This paper proposes the software reliability growth model which incorporates periodic service packs, unpredictable patches and operational environment. Based on the proposed model, we derive optimal release time to minimize total cost composed of fixing an error, testing and maintenance. Using numerical examples, optimal release time is determined and illustrated.

The study on automatic function testing as accleration life testing(ALT) for industrial control modules (제어모듈의 가속수명시험을 위한 자동기능점검시스템에 관한 연구)

  • Mo, Sung-Hee;Ham, Jung-Keol;Jung, Chang-Ki;Shin, Youn-Oh
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.997-1001
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    • 1999
  • 국내 제조업체의 기술발달로 인해 각 산업계의 모듈 및 시스템에 대한 차체 개발과 더불어 이전 외국업체에 의해 설계된 시스템들에 대한 국산화가 많이 이루어지고 있다. 신뢰성평가에 있어서도 예전부터 수행하고 있는 부품단위의 시험평가와 더불어 최근에는 모듈 류에 대한 시험평가요구가 증가하고 있으며 특히, 이들 개발 모듈류에 대한 신뢰성확보를 위해 가속수명시험(ALT)과 초기고장을 가려내기 위한 번인(Burn-In)시험이 많이 행해지고 있다. 이들 시험을 위해서는 장시간에 걸쳐 그 모듈류의 기능을 점검하고 모니터링 할 수 있는 측정자동화 시스템이 필수적이다. 본 연구에서는 이런 측정 자동화시스템 제작에 관련된 내용을 기술하고 실제 적용 사례를 제시하여 모듈류의 가속수명시 기능점검에 대해 논하였다.

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Quality Testing Model of Mobile RFID Middleware (모바일 RFID 미들웨어 품질 평가 모델)

  • Jung, Hye-Jung
    • The Journal of Information Technology
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    • v.10 no.4
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    • pp.85-93
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    • 2007
  • RFID applied in many area. I think that RFID enlarge for our life more and more. The application technology of RFID change the Mobile RFID using mobile phone and PDF etc. I think, Mobile RFID enlarge application technology gradually. In this paper, we propose the quality measurement metrics for mobile RFID middleware. I propose the quality testing model for interoperability and security of mobile RFID middleware. We examine the international standard for mobile RFID and software testing. In this paper, I proposed the evaluation model of mobile RFID middleware on the basis of international standard ISO/IEC 9126-2 and ISO/IEC 25000 series.

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Automotive Embedded System Software Development and Validation with AUTOSAR and Model-based Approach (AUTOSAR와 모델기반 기법을 적용한 차량 임베디드 시스템 소프트웨어의 개발 및 검증 기법)

  • Kum, Dae-Hyun;Son, Jang-Kyung;Kim, Myung-Jin;Son, Joon-Woo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.12
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    • pp.1179-1185
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    • 2007
  • This paper presents a new approach to automotive embedded systems development and validation. Recently automotive embedded systems become even more complex and the product life cycle is getting reduced. To overcome these problems AUTOSAR, a standardized software platform and component based approach, was introduced. Model-based approach has been widely applied in the development of embedded systems and has strong benefits such as early validation and automated testing. In this paper cooperative development and validation of AUTOSAR and model-based approach are introduced and automated testing techniques are proposed. With the proposed techniques we can improve complexity management through increased reuse and exchangeability of software module and automated testing is realized.