• Title/Summary/Keyword: Tool failure

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Evaluation of Bond Performance for AC overlay on PCC Pavement (AC / PCC 복합포장 경계면 재료의 부착 성능 평가)

  • Kim, Dong kyu;Hwang, Hyun sik;Christopher, Jabonero;Ryu, Sung woo;Cho, Yoon ho
    • International Journal of Highway Engineering
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    • v.18 no.5
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    • pp.1-9
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    • 2016
  • PURPOSES : This study focuses on the evaluation of interface performance with varying surface texture and tack coat application in an asphalt overlay. METHODS : The evaluation is carried out in two phases: tracking test and interface bond strength test. Using an image processing tool, tracking test is conducted to evaluate the susceptibility of the tack coat material to produce excessive tracking during application. Using the pull-off test method, the bond strength test is performed to determine the ability of the interface layer to resist failure. RESULTS : Results show that the underseal application yields less tracking compared to other applications. However, the bond strength is barely within the minimum acceptable value. On the other hand, RSC-4 produces higher bond strength for all surface types, but the drying time is long, which produces excessive tracking. CONCLUSIONS : While underseal application may be suitable for a trackless condition, the bond strength is less appealing compared to the rest of the tack applications available. RSC-4 demonstrated a high and consistent bond strength performance, but more time is required for drying to avoid excessive tracking. Tack coat application and surface type combination produce varying results. Therefore, these should be considered when selecting suitable future tack coat application options.

Developing a Bayesian Network Model for Real-time Project Risk Management (실시간 프로젝트 위험관리를 위한 베이지안 네트워크 모형의 개발)

  • Kim, Jee-Young;Ahn, Sun-Eung
    • IE interfaces
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    • v.24 no.2
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    • pp.119-127
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    • 2011
  • Most companies have been increasing temporary work projects to maximize the usage of their resources. They also have been developing the effective techniques for analyzing and managing the state of the projects. In order to monitor the state of a project in real-time and predict the project's future state more accurately, this paper suggests the Bayesian Network (BN) as a tool for discovering the causes of project risk and presenting the failure probability of the project. The proposed BN modeling method with consideration of the Earned Value Management (EVM) method shows how to induce the predictive and conditional probability of the risk occurrence in the future. The advantages of the suggested model are (1) that the cause of a project risk can be easily figured out via the BN, (2) that the future value of the project can be sufficiently increased by updating relevant components of the project, and (3) that more credible prediction can be made in the similar and future situation by using the data obtained in current analysis. A numerical example is also given.

Reliability Design of MEMS based on the Physics of Failures by Stress & Surface Force (응력 및 표면 고장물리를 고려한 MEMS 신뢰성 설계 기술)

  • Lee, Hak-Joo;Kim, Jung-Yup;Lee, Sang-Joo;Choi, Hyun-Ju;Kim, Kyung-Shik;Kim, J.H.
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1730-1733
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    • 2007
  • As semiconductor and MEMS devices become smaller, testing process during their production should follow such a high density trend. A circuit inspection tool "probe card" makes contact with electrode pads of the device under test (DUT). Nowadays, electrode pads are irregularly arranged and have height difference. In order to absorb variations in the heights of electrode pads and to generate contact loads, contact probes must have some levels of mechanical spring properties. Contact probes must also yield a force to break the surface native oxide layer or contamination layer on the electrodes to make electric contact. In this research, new vertical micro contact probe with bellows shape is developed to overcome shortage of prior work. Especially, novel bellows shape is used to reduce stress concentration in this design and stopper is used to change the stiffness of micro contact probe. Variable stiffness can be one solution to overcome the height difference of electrode pads.

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Application of Time-Frequency Analysis as a Tool for Noise Quality Control of DC Motor Systems (DC 모터계의 소음 품질관리를 위한 시간-주파수 분석의 적용)

  • 임상규;최창환
    • Journal of KSNVE
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    • v.9 no.4
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    • pp.841-848
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    • 1999
  • In the quality assurance check process of DC motor systems, even though the overall sound pressure level is acceptable, there is an incident that subjective evaluation leads to failure in product quality due to annoying noise. This kind of problem may be originated from the manufacturing or assembly process. In this paper, the transient spectral analysis, or the time-frequency analysis is applied to the noise quality problem. For the case study, the cause of annoying noise in the wind shield wiper motor is experimentally analyzed in detail. It is concluded that the defect in the shaft causes the impact noise which is not detectable by steady spectral analysis. Also demonstrated is how the time-frequency analysis is effectively applied to the annoying noise identification of the rotor-gear system.

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Structural damage detection of steel bridge girder using artificial neural networks and finite element models

  • Hakim, S.J.S.;Razak, H. Abdul
    • Steel and Composite Structures
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    • v.14 no.4
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    • pp.367-377
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    • 2013
  • Damage in structures often leads to failure. Thus it is very important to monitor structures for the occurrence of damage. When damage happens in a structure the consequence is a change in its modal parameters such as natural frequencies and mode shapes. Artificial Neural Networks (ANNs) are inspired by human biological neurons and have been applied for damage identification with varied success. Natural frequencies of a structure have a strong effect on damage and are applied as effective input parameters used to train the ANN in this study. The applicability of ANNs as a powerful tool for predicting the severity of damage in a model steel girder bridge is examined in this study. The data required for the ANNs which are in the form of natural frequencies were obtained from numerical modal analysis. By incorporating the training data, ANNs are capable of producing outputs in terms of damage severity using the first five natural frequencies. It has been demonstrated that an ANN trained only with natural frequency data can determine the severity of damage with a 6.8% error. The results shows that ANNs trained with numerically obtained samples have a strong potential for structural damage identification.

Restoration of pre-damaged RC bridge columns using basalt FRP composites

  • Fahmy, Mohamed F.M.;Wu, Zhishen
    • Earthquakes and Structures
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    • v.14 no.5
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    • pp.379-388
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    • 2018
  • This study aims to identify the effect of both longitudinal reinforcement details and damage level on making a decision of repairing pre-damaged bridge columns using basalt fiber reinforced polymer (BFRP) jackets. Two RC bridge columns with improper details of the longitudinal and/or transverse reinforcement were tested under the effect of a constant axial load and increasing lateral cyclic loading. Test results showed that the lap-splice column exhibited an inferior performance where it showed rapid degradation of strength before achieving the theoretical strength and its deformation capacity was limited; however, quick restoration is possible through a suitable rehabilitation technique. On the other hand, expensive repair or even complete replacement could be the decision for the column with the confinement failure mode. After that, a rehabilitation technique using external BFRP jacket was adopted. Performance-based design details guaranteeing the enhancement in the inelastic performance of both damaged columns were addressed and defined. Test results of the repaired columns confirmed that both reparability and the required repairing time of damage structures are dependent on the reinforcement details at the plastic hinge zone. Furthermore, lap-splice of longitudinal reinforcement could be applied as a key design-tool controlling reparability and restorability of RC structures after massive actions.

Subsidy Rationalisation for General Purpose Flour: Market and Economics Implications

  • Kari, Fatimah Binti;Masud, Muhammad Mehedi;Saifullah, Md. Khaled
    • The Journal of Asian Finance, Economics and Business
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    • v.4 no.2
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    • pp.25-36
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    • 2017
  • Subsidies are an instrumental policy making tool for many governments, but their importance depends on the market situation of the national economy. Efficient subsidy implementation would allow the government to correct market failure thereby aligning social and private costs and benefit. The general objective of this study is to justify the need to rationalise subsidies for food items such as flour. This study assessed the structure and conducts of the general purpose flour market in Malaysia; and analysed the impact of subsidies on market performance to recommend policies to increase market efficiency under the subsidy rationalisation program. To accomplish these objectives, the study adopted a microeconomics market analysis as well as the standard structure and performance analysis method. These two approaches showed the characteristics of an industry's consumer behaviour, competition, as well as the efficiency associated with government regulatory policies on the flour industry. One of the biggest influences on the domestic market is related to the food consumption behaviour of the general population. Food consumption behaviour reflects global trends. As income rises, food trends tend to be consumed in processed form or in such a way that adds value in another manner such as the preparation of food products.

An Exploratory Study on the Relative Importances of the Critical Success Factors in an ERP Project (ERP 프로젝트 주요 성공요인의 상대적 중요도에 대한 탐색적 연구)

  • Han, Sang-Cheol;Lee, Gil-Hyung
    • Journal of Information Technology Services
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    • v.4 no.1
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    • pp.57-69
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    • 2005
  • The ERP system which has been adopted as a tool for integration of information systems and for innovation of business process. And it is regarded to be able to maximize the productivity of business process and achieve process innovation based on the best practice incorporated in the ERP. To achieve process innovation through ERP, strong sponsorship from top management and building consensus through the entire organization is required to be backed UP. There are many cases of the failure of Process Innovation due to reluctance of corporate members to change. In the result of the case study, it seems to be difficult to build the consensus of the related groups to ERP project. There are still argues after project, on whether the project was success or not. Through the AHP analysis for the success factors, it is explored that the reason is that several groups of the company had different expectation for the project. And to achieve the aimed process Innovation, the project members in the related departments should build the consensus of expectation on the project.

The Formation of Resistance on Multi-culture Social Emotion and Countermeasures in Korea

  • Kim, Bo-Suk;Kim, Yeong-Ok;Jung, Myung-Hee
    • Journal of Distribution Science
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    • v.15 no.1
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    • pp.21-30
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    • 2017
  • Purpose - These days, Korean society with more than 2 million foreigners has made multi-cultural society quickly. Multi-cultural society has become popular and anti multi-cultural phenomenon has grown up gradually against Korea's traditional habits. Research design, data, and methodology - European countries that were said to be multi-cultural society had suffered from terror, riot and other social conflicts. The study examined Koreans' racism and anti multi-cultural emotion to investigate the conditions and causes of anti multi-cultural emotion. Further, this study investigates a prevention of the worst case such as Norway terror and the countermeasures compared to each country's social customs. Results - Koreans are not generous to the foreigners. Foreign countries' cases after failures in multi-cultural society might give future implications on multi-cultural society in Korea. Conclusions - Korean society have not produced new one by introducing another races, nationality and culture not cognizing failure experiences of multi-culturalism like Europe. Nonetheless, Korean society shall not give up multi-culturalism. Korean society shall prepare for multi-culturalism society to lessen social conflict as much as possible and not to neglect anti culturalism emotion producing social conflict, and shall investigate the related causes to lessen anti multi-culturalism emotion and to integrate Korean style of multi-culturalism society for Korea as a tool of nation management.

Stress Simulation on Suspended Porcelain Insulators with Cement Displacement

  • Han S. W.;Cho H. G.;Park G. H.;Lee D. I.;Choi I. H;Kim T. Y.
    • Transactions on Electrical and Electronic Materials
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    • v.4 no.3
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    • pp.19-24
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    • 2003
  • The experimental and simulation study of insulator failure by cement growth on suspended insulators (16,500kgf) for transmission line was discussed. To get more practical and analytic calculation results, the advanced program was used. This analysis tool was possible to calculate stress behaviors with mechanical loading when cement displacement happened. From simulation results, the. cement displacement changed with linear according to temperature. The shear stress was about $7 kgf/mm^2$ at $0.07\%$ displacement provided from $200^{\circ}C$, then it could be seen that the cement would be fractured even if $0.07\%$ displacement acted, because the cement had about $7-9 kgf/mm^2$ flexure strength. The curve patterns of shear stress with the increase of mechanical loading were changed at $0.02\%$ as a turning point, when the cement displacement was over $0.02\%$ the shear stresses decreased reversely with the increase of mechanical loading. From analysis on porcelain body it was known that there were enough margin to protect the fracture of porcelain body before the cement