• Title/Summary/Keyword: scan testing

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Verification of System using Master-Slave Structure (Master-Slave 기법을 적용한 System Operation의 동작 검증)

  • Kim, In-Soo;Min, Hyoung-Bok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.199-202
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    • 2009
  • Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.

Two-Dimensional Numerical Modeling and Simulation of Ultrasonic Testing

  • Yim, Hyun-June;Baek, Eun-Sol
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.6
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    • pp.649-658
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    • 2002
  • As an attempt to further improve the reliability and effectiveness of ultrasonic testing (UT), a two-dimensional numerical simulator of UT was developed. The simulator models the wave medium (or test object) using the mass-spring lattice model (MSLM) that consists of mass-points and springs. Some previous simulation results, obtained by using MSLM, are briefly reviewed in this paper, for propagation, reflection, and scattering of ultrasonic waves. Next, the models of transmitting and receiving piezoelectric transducers are introduced with some numerical results, which is a main focus of this paper. The UT simulator, established by combining the transducer models with the MSLM, was used to simulate many UT setups. In this paper, two simple setups are considered as examples, and their simulated A-scan signals are discussed. The potential of the MSLM, transducer models, and the UT simulator developed in this study to be used in the actual UT is confirmed.

Performance testing of a FastScan whole body counter using an artificial neural network

  • Cho, Moonhyung;Weon, Yuho;Jung, Taekmin
    • Nuclear Engineering and Technology
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    • v.54 no.8
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    • pp.3043-3050
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    • 2022
  • In Korea, all nuclear power plants (NPPs) participate in annual performance tests including in vivo measurements using the FastScan, a stand type whole body counter (WBC), manufactured by Canberra. In 2018, all Korean NPPs satisfied the testing criterion, the root mean square error (RMSE) ≤ 0.25, for the whole body configuration, but three NPPs which participated in an additional lung configuration test in the fission and activation product category did not meet the criterion. Due to the low resolution of the FastScan NaI(Tl) detectors, the conventional peak analysis (PA) method of the FastScan did not show sufficient performance to meet the criterion in the presence of interfering radioisotopes (RIs), 134Cs and 137Cs. In this study, we developed an artificial neural network (ANN) to improve the performance of the FastScan in the lung configuration. All of the RMSE values derived by the ANN satisfied the criterion, even though the photopeaks of 134Cs and 137Cs interfered with those of the analytes or the analyte photopeaks were located in a low-energy region below 300 keV. Since the ANN performed better than the PA method, it would be expected to be a promising approach to improve the accuracy and precision of in vivo FastScan measurement for the lung configuration.

Simulation of Time of Flight Diffraction Signals for Reactor Vessel Head Penetrations (원자로 상부 헤드 관통관 TOFD 신호 시뮬레이션)

  • Lee, Tae-Hun;Kim, Young-Sik;Lee, Jeong-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.4
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    • pp.273-280
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    • 2016
  • The simulation of nondestructive testing has been used in the prediction of the signal characteristics of various defects and in the development of the procedures. CIVA, a simulation tool dedicated to nondestructive testing, has good accuracy and speed, and provides a three-dimensional graphical user interface for improved visualization and familiar data displays consistent with an NDE technique. Even though internal validations have been performed by the CIVA software development specialists, an independent validation study is necessary for the assessment of the accuracy of the software prior to practical use. In this study, time of flight diffraction signals of ultrasonic inspection of a calibration block for reactor vessel head penetrations were simulated using CIVA. The results were compared to the experimentally inspected signals. The accuracy of the simulated signals and the possible range for simulation were verified. It was found that, there is a good agreement between the CIVA simulated and experimental results in the A-scan signal, B-scan image, and measurement of depth.

Design and Implementation of Flaw Image processing System for Automated Ultrasonic Testing System (자동 초음파 검사를 위한 결함 영상 처리 시스템의 설계 및 구현)

  • Kim, Han-Jong;Park, Jong-Hoon;Kim, Chul-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.1
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    • pp.225-232
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    • 2010
  • In this study, an automated ultrasonic testing system and post signal and image processing techniques are developed in order to construct ultrasonic flaw images in weldments. Image processing algorithms are built into the flaw image processing system for the automated ultrasonic testing system. The developed signal and image analysis algorithms addressed in this study include an A-Scan data compression algorithm, ultrasonic image amplification algorithm and B-scan flaw image correction algorithm(SAFT). This flaw image processing system for the automated ultrasonic testing system can be applied to various inspection fields.

Implementation of Ultrasonic Immersion Technique for Babbitt Metal Debonding in Turbine Bearing (초음파 수침법을 이용한 터빈베어링 Babbitt금속 박리 검사 기술)

  • Jung, Gye-Jo;Park, Sang-Ki;Cho, Yong-Sang;Park, Byung-Cheol;Kil, Doo-Song
    • Journal of the Korean Society for Nondestructive Testing
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    • v.24 no.4
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    • pp.348-353
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    • 2004
  • This study is aimed for the implementation of ultrasonic method to assess the reliability of turbine bearings. A modified ultrasonic immersion technique was carried out in both laboratory experiment and field application. From the laboratory results, we confirmed that the condition of interface layer between the babbitt and base metal be monitored by the C-Scan. The C-scan image by the ultrasonic immersion test can be used successfully to observe the condition of interface layer. The testing with a focused transducer provides a promising approach for estimating the extent of the damaged region and observing the interface layer effectively. The difference of the ultrasonic reflection ratio between the bonding and debonding area at the interface layer is one of the key parameters for assessing the extent of the damaged area; additionally, the reflection amplitude exhibits a favorable correlation with the overall damage level. The technique developed in this study was applied to the inspection of the turbine bearings at several power plants in Korea whereby the applicability in the field can be ascertained.

A Reliability Study of the Phased Array Ultrasonic Testing: Case Study for the Composite Blades of Wind Power Generation (위상배열 초음파 탐지검사의 신뢰성에 관한 연구: 풍력발전기 복합소재 블레이드 사례연구)

  • Kang, Byung Kwon;Lim, Ik Sung;Koo, Ilseob
    • Journal of Applied Reliability
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    • v.16 no.4
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    • pp.338-346
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    • 2016
  • Purpose: The purpose of this research is to improve the reliability of the composite material blades used for the wind power generator, by applying the phased array ultrasonic testing technique out of the many nondestructive test into the blades. Method: The wind power generation composite blades are used, as a case study, in order to evaluate the reliability of the phased array ultrasonic testing technique. Defects that are most likely occurred in the field are injected into the different locations of the three different types of artificial test pieces and then phased array ultrasonic testing technique are applied to evaluate the reliability of its effectiveness. Result: As a result of the analysis of the defect signals by applying the A scan and B scan simultaneously, depth and width of the defect could be obtained. An area of defect was proportional to the amount of energy by color in B scan image. The larger amount of energy, reflected amount of energy was appeared in the order of red, orange, yellow, blue color. Conclusion: The most reliable testing method to detect the defect in composite blades for wind power generation is considered to be the combination of the other destructive testing technique with the phased array ultrasonic testing since the PAUT alone could not detect all range of the defects in the blades.

Test Methodology for Multiple Clocks Single Capture Scan Design based on JTAG IEEE1149.1 Standard (IEEE 1149.1 표준에 근거한 다중 클럭을 이용한 단일 캡쳐 스캔 설계에 적용되는 경계 주사 테스트 기법에 관한 연구)

  • Kim, In-Soo;Min, Hyoung-Bok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.5
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    • pp.980-986
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    • 2007
  • Boundary scan test structure(JTAG IEEE 1149.1 standard) that supports an internal scan chain is generally being used to test CUT(circuit under test). Since the internal scan chain can only have a single scan-in port and a single scan-out port; however, existing boundary test methods can not be used when multiple scan chains are present in CUT. Those chains must be stitched to form a single scan chain as shown in this paper. We propose an efficient boundary scan test structure that adds a circuit called Clock Group Register(CGR) for multiple clocks testing within the design of multiple scan chains. The proposed CGR has the function of grouping clocks. By adding CGR to a previously existing boundary scan design, the design is modified. This revised scan design overcomes the limitation of supporting a single scan-in port and out port, and it bolsters multiple scan-in ports and out ports. Through our experiments, the effectiveness of CGR is proved. With this, it is possible to test more complicated designs that have high density with a little effort. Furthermore, it will also benefit in designing those complicated circuits.

A Development of Computer Controlled 5 Axis Ultrasonic Testing System (컴퓨터제어식 5축 자동초음파탐상장치의 개발)

  • Kim, Y.S.;Kim, J.G.;Park, J.C.;Kim, N.I.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.10 no.2
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    • pp.32-37
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    • 1990
  • A computer controlled 5 axis ultrasonic testing system is developed in order to detect flaws in special parts with complex shape. The various kinds of ultrasonic test can be performed automatically using computer program which was developed by DHI(Daewoo Heavy Industries Ltd.). By use of this computer program, the detector location can be programed and the amplitude signal of echo can be processed digitally. The test results can be plotted graphically on a high resolution display monitor in real time base. The test data can be also saved in magnetic memory devices(HDD or FDD) as well as in the form of hard copy through color printer. The computer software contains c- scan, c+a scan processing programs as well as statistical analysis for test data.

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Reducing Test Power and Improving Test Effectiveness for Logic BIST

  • Wang, Weizheng;Cai, Shuo;Xiang, Lingyun
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.5
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    • pp.640-648
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    • 2014
  • Excessive power dissipation is one of the major issues in the testing of VLSI systems. Many techniques are proposed for scan test, but there are not so many for logic BIST because of its unmanageable randomness. This paper presents a novel low switching activity BIST scheme that reduces toggle frequency in the majority of scan chain inputs while allowing a small portion of scan chains to receive pseudorandom test data. Reducing toggle frequency in the scan chain inputs can reduce test power but may result in fault coverage loss. Allowing a small portion of scan chains to receive pseudorandom test data can make better uniform distribution of 0 and 1 and improve test effectiveness significantly. When compared with existing methods, experimental results on larger benchmark circuits of ISCAS'89 show that the proposed strategy can not only reduce significantly switching activity in circuits under test but also achieve high fault coverage.