• Title/Summary/Keyword: defect engineering

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An Overview of Time Estimation in the Appraisal of Completeness for Software

  • Kim, Yukyong
    • Journal of Software Assessment and Valuation
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    • v.16 no.1
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    • pp.21-26
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    • 2020
  • The completeness appraisal of software is performed in various forms, such as assessing the completion level in the development process, calculating the defect rate, estimating the development cost, and calculating the redevelopment cost. Along with this, the problem that is often dealt with is estimation of the development time. Even in a dispute over completeness due to delays in software development, issues of calculating an appropriate development time required to develop a delivery software or a development time required for change requests are often included in the appraisal request. In this paper, we introduce the procedure and method for estimating the appropriate project time of software development so that the appraiser can be applied to the appraisal work for determining the completeness. The method is based on the manual for calculating the appropriate project period of software development project.

Virtual reality application on MFL gas pipeline inspection system

  • Kim, Jae-Joon
    • Journal of Korea Society of Industrial Information Systems
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    • v.15 no.4
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    • pp.47-52
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    • 2010
  • This paper describes a visualization technique that animates geometrical defect data that are extracted using a magnetic flux leakage (MFL) operating system on nondestructive evaluation (NDE). Since data are collected from different locations and often not regular, the data must be converted to the standard format that is used within the pipeline in visualization procedures. In order to navigate inside of the pipeline, 3D virtual objects are generated and are able to explore the pipeline continuously. The major objectives of this paper are to characterize, generate general shape of defects, and enable computer interaction in virtual environment. Pipeline navigation system (PNS) has introduced the framework for interactive visual applications based upon the principles of modeling 3D objects. PNS presents some preliminary efforts to enable the user to interact human and computer with each other.

Performance change of defect classification model of rotating machinery according to noise addition and denoising process (노이즈 추가와 디노이징 처리에 따른 회전 기계설비의 결함 분류 모델 성능 변화)

  • Se-Hoon Lee;Sung-Soo Kim;Bi-gun Cho
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2023.07a
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    • pp.1-2
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    • 2023
  • 본 연구는 환경 요인이 통제되어 있는 실험실 데이터에 산업 현장에서 발생하는 유사 잡음을 노이즈로 추가하였을 때, SNR비에 따른 노이즈별 STFT Log Spectrogram, Mel-Spectrogram, CWT Spectrogram 총 3가지의 이미지를 생성하고, 각 이미지를 입력으로 한 CNN 결함 분류 모델의 성능 결과를 확인하였다. 원본 데이터의 영향력이 큰 0db 이상의 SNR비로 합성할 경우 원본 데이터와 분류 결과상 큰 차이가 존재하지 않았으며, 노이즈 데이터의 영향이 큰 0db 이하의 SNR비로 합성할 경우, -20db의 STFT 이미지 기준 약 26%의 성능 저하가 발생하였다. 또한, Wiener Filtering을 통한 디노이징 처리 이후, 노이즈를 효과적으로 제거하여 분류 성능의 결과가 높아지는 점을 확인하였다.

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Integration of Multi-scale CAM and Attention for Weakly Supervised Defects Localization on Surface Defective Apple

  • Nguyen Bui Ngoc Han;Ju Hwan Lee;Jin Young Kim
    • Smart Media Journal
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    • v.12 no.9
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    • pp.45-59
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    • 2023
  • Weakly supervised object localization (WSOL) is a task of localizing an object in an image using only image-level labels. Previous studies have followed the conventional class activation mapping (CAM) pipeline. However, we reveal the current CAM approach suffers from problems which cause original CAM could not capture the complete defects features. This work utilizes a convolutional neural network (CNN) pretrained on image-level labels to generate class activation maps in a multi-scale manner to highlight discriminative regions. Additionally, a vision transformer (ViT) pretrained was treated to produce multi-head attention maps as an auxiliary detector. By integrating the CNN-based CAMs and attention maps, our approach localizes defective regions without requiring bounding box or pixel-level supervision during training. We evaluate our approach on a dataset of apple images with only image-level labels of defect categories. Experiments demonstrate our proposed method aligns with several Object Detection models performance, hold a promise for improving localization.

Sequential conversion from line defects to atomic clusters in monolayer WS2

  • Gyeong Hee Ryu;Ren-Jie Chan
    • Applied Microscopy
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    • v.50
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    • pp.27.1-27.6
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    • 2020
  • Transition metal dichalcogenides (TMD), which is composed of a transition metal atom and chalcogen ion atoms, usually form vacancies based on the knock-on threshold of each atom. In particular, when electron beam is irradiated on a monolayer TMD such as MoS2 and WS2, S vacancies are formed preferentially, and they are aligned linearly to constitute line defects. And then, a hole is formed at the point where the successively formed line defects collide, and metal clusters are also formed at the edge of the hole. This study reports a process in which the line defects formed in a monolayer WS2 sheet expends into holes. Here, the process in which the W cluster, which always occurs at the edge of the formed hole, goes through a uniform intermediate phase is explained based on the line defects and the formation behavior of the hole. Further investigation confirms the atomic structure of the intermediate phase using annular dark field scanning transition electron microscopy (ADF-STEM) and image simulation.

A study on insert molding application to secondary battery cap assembly (이차전지 캡 어셈블리 인서트 몰딩 적용에 관한 연구)

  • Seung-Min Woo;Geum-Seok Yoon
    • Design & Manufacturing
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    • v.18 no.3
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    • pp.54-63
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    • 2024
  • This study applied the insert molding technology which is a metal and resin joining method, to secondary battery prismatic cap assembly component and investigated the improvement comparing with standard PHEV2 Type of prismatic battery under the goal of enhancing the global market competitiveness by reducing the number of cap assembly sub-component and simplifying its manufacturing processes. Insert molding replaced the rivet terminal which is composed of 6 parts to which led significant decreasing of product cost, weight and resistance and increasing tensile strength. The angle of current collector to cap plate is a key of leakage defect which is determined by temperature of product and mold, injection temperature, pressure and time and these data can be used for bigger size of insert cap assembly as the demand of high capacity battery is getting high

Analysis of defects caused by halo defects during injection molding (사출성형 중 달무리 현상에 의한 불량에 대한 분석)

  • Lee, Soon-Young;Park, Eun-Min;Kim, Do-Hun;Kim, Yong-Chul;Yang, Chul-Seung;Jin, Gyeong-Min;Kim, Sun-Kyoung
    • Design & Manufacturing
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    • v.13 no.4
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    • pp.57-62
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    • 2019
  • In this study, we investigated the halo surface defection of various phenomenon occurred during the injection molding process which is caused by the thinning of the product thickness and the importance of the appearance. Surface analysis was performed to observe the difference between the surface where defects appeared and the surface which did not appear. Based on these results, we analyzed the phenomenon of halo surface defects was caused by unstable flow of resin generated in injection molding and velocity change of flow front. Furthermore, we will conduct a clear analysis of halo surface defects through observations through optical microscopy and subsequent observations with atomic force microscope. It has been analyzed that halo in PP is due to the rheological difference between the crystalline and amorphous regions while that in PC/ABS is due to shear separation of PC and ABS.

Evaluation of Bacterial Transport Models for Saturated Column Experiments

  • Ham, Young-Ju;Kim, Song-Bae;Kim, Min-Kyu;Park, Seong-Jik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.7
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    • pp.55-63
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    • 2006
  • Bacterial transport models were evaluated in this study to determine the suitable model at describing bacterial transport in saturated column experiments. Four models used in the evaluation were: advective-dispersive equation (ADE) + equilibrium sorption/retardation (ER) + kinetic reversible sorption (KR) (Model I), ADE + two-site sorption (Model 2), ADE + ER + kinetic irreversible sorption (KI) (Model 3), ADE + KR + KI (Model 4). Firstly, analyses were performed with the first experimental data, showing that Model 4 is appropriate for describing bacterial transport. Even if Model 1 and 2 fit well to the observed data, they have a defect of not including the irreversible sorption, which is directly related to mass loss of bacteria. Model 3 can not properly describe the tailing observed in the data. However, further analysis with the second data indicates that Model 4 can not describe retardation of bacteria, even if the sorption-related parameters are varied. Therefore, Model 4 is modified by incorporating retardation factor into the model, resulting in the improved fitting to the data. It indicates that the transport model, into which retardation, kinetic reversible sorption, and kinetic irreversible sorption are incorporated, is suitable at describing bacterial transport in saturated column experiments. It is expected that the selected transport model could be applied to properly analyze the bacterial transport in saturated porous media.

Synergy study on charge transport dynamics in hybrid organic solar cell: Photocurrent mapping and performance analysis under local spectrum

  • Hong, Kai Jeat;Tan, Sin Tee;Chong, Kok-Keong;Lee, Hock Beng;Ginting, Riski Titian;Lim, Fang Sheng;Yap, Chi Chin;Tan, Chun Hui;Chang, Wei Sea;Jumali, Mohammad Hafizuddin Hj
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1564-1570
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    • 2018
  • Charge transport dynamics in ZnO based inverted organic solar cell (IOSC) has been characterized with transient photocurrent spectroscopy and localised photocurrent mapping-atomic force microscopy. The value of maximum exciton generation rate was found to vary from $2.6{\times}10^{27}m^{-3}s^{-1}$ ($J_{sat}=79.7A\;m^{-2}$) to $2.9{\times}10^{27}m^{-3}s^{-1}$ ($J_{sat}=90.8A\;m^{-2}$) for devices with power conversion efficiency ranging from 2.03 to 2.51%. These results suggest that nanorods served as an excellent electron transporting layer that provides efficient charge transport and enhances IOSC device performance. The photovoltaic performance of OSCs with various growth times of ZnO nanorods have been analysed for a comparison between AM1.5G spectrum and local solar spectrum. The simulated PCE of all devices operating under local spectrum exhibited extensive improvement with the gain of 13.3-3.7% in which the ZnO nanorods grown at 15 min possess the highest PCE under local solar with the value of 2.82%.

Influence of Coating Defect Ratio on Tribological Behavior Determined by Electrochemical Techniques (전기화학적 분석을 통해 산출된 코팅 결함율이 트라이볼로지적 특성에 미치는 영향 평가)

  • Lee Young-Ze;Kim Woo-Jung;Ahn Seung-Ho;Kim Ho-Gun;Kim Jung-Gu;Cho Chung-Woo
    • Tribology and Lubricants
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    • v.20 no.6
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    • pp.306-313
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    • 2004
  • Many of the current development in surface modification engineering are focused on multilayered coatings, which have the potential to improve the tribological properties. Four different multilayered coatings were deposited on AISI D2 steel in this study. The prepared samples are designed as $WC-Ti_{0.6}Al_{0.4}N,\;WC-Ti_{0.53}Al_{0.47}N,\;WC-Ti_{0.5}Al_{0.5}N\;and\;WC-Ti_{0.43}Al_{0.57}N$. The multilayered coatings were investigated with respect to coating surface and cross-sectional morphology, roughness, adhesion, hardness, porosity and tribological behaviors. Especially, wear tests of four multilayered coatings were performed by using a ball-on-disc configuration with a linear sliding speed of 0.017 m/sec and a normal load of 5.38 N load. The tests were carried out at room temperature in air by employing AISI 52100 steel ball $(H_R\;=\;66) $ having a diameter of 10 mm. The surface morphology, and topography of the wear scars of samples and balls have been determined by using scanning electron spectroscopy (SEM). Also, wear mechanism was determined by using SEM coupled with energy-dispersive spectroscopy (EDS). Results have showed an improved wear resistance of the $WC-Ti_{1-x}Al_xN$coatings with increasing of Al (aluminum) concentration.