• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.553-563
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• 2015

Reportedly the fatality rate from secondary collision is six times higher than the average fatality rate from all traffic accidents. So prevention of the secondary collision is attracting significant attention from automotive industries. However, the secondary collision prevention systems that have been developed are not considering possibility of brake actuator failure that can occur by the impact during the initial collision. In this paper, a new system has been developed that could prevent secondary collision even in case of brake actuator failure by taking advantage of still operating actuators. In this system, a steering control is performed for maintaining a lane by using linear quadratic regulator. Additionally, the system attempts differential brake control with the remaining braking capability to stop the vehicle in the shortest distance. Through simulation in various collision scenarios, the system has demonstrated significant potential of preventing secondary collision that could otherwise have resulted in severe fatality.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.277-279
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• 2005

Recently, due to the increase of power conversion devices and nonlinear loads with the development of information, communication and control technologies, the instantaneous minute interruption factors such as voltage & current harmonics, surge occurring frequency, instantaneous voltage variation, voltage unbalance, flicker etc. have greatly threatened the power quality, and the deterioration of electric power facilities and the functional error of controllers are increasing. As such an instantaneous minute interruption appears to be small and local, accurate evaluation with measurement is difficult and total analysis system is required through a wide range of power quality effect analysis such as the simultaneous measurement on various power supply phenomena and the analysis on the interrelation with system loads. Most of conventional power quality diagnosis equipments have beer developed and applied, which were able to measure the stability rate of frequency, the stability rate of voltage, the electricity-failure duration etc, However, they were insufficient to analyze the system present situation, understand the cause of the failure occurred by the problem of power quality and analyze out the phenomena. Accordingly, this study will address the development of the system for a wide range of power quality diagnosis over the present level, the system for supporting the determination such as the analysis on risk factors, failure mode and impact, the system for harmonic evaluation based on international standards(IEC 61000 Series) and the total power quality diagnosis network & system with the extension and openness as a local and national-scale broadband power quality diagnosis system.

• Journal of Korea Port Economic Association
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• v.28 no.4
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• pp.169-191
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• 2012

This study is to investigate the strategy on forming a long term relationship between logistics service provider and demander including maintaining strategy of it. For these purposes, effect on the organization and human factor of Logistics service companies and also, impact on the customer trust and relational commitment against service recovery are analysed. Literature review and empirical study are used to modify research model and to develop questionnaire for logistics service companies. Reliability for measuring procedure yields the same result on repeated trials and validity for identifying the accuracy of the accrual measuring instrument are also used. Suggested hypothesis are verified through multiple regression method and the testing results are shown as follows; First, organization and human factor have a positive effect to the service recovery satisfaction against the service failure of logistics service providing company. Second, the service recovery satisfaction also leads a positive effect on the customer trust and relational commitment.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.85-90
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• 2011

With regard to reliability of solder joint, the significant failures include open defects that occurs from alignment problem, Head in Pillow by PCB's warpage, the crack of solder by CTE mismatch, and the crack of IMC layer by mechanical impact. Especially as PCB down-sizing and surface finish is under progress, brittle failure of IMC layer between solder bump and PCB pad becomes a big issue. Therefore, it requires enhancing the level of difficulty in the existing assessment method and improving the measurement through the study on the mechanism of IMC formation, growth and brittle failure. Under this circumstance, this study is intended to suggest the direction of research for improving the reliability on the crack such as improvement of IMC brittle fracture.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.379-385
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• 2003

In the existing method to design geosynthetic reinforced embankment, the required strength of reinforcements is determined by vertical stress only rather than strain. This strength is not in accord with tensile strength that behaves as reinforcement in earth structures. The reinforcement and adjacent soil on the failure plan behave in one unit at the initial stress phase but they make a gap in strain as stress increases. This issue may cause a big impact as a critical factor on geosynthetic reinforcement design in earth structures. The quantitative analysis on strain behavior was performed with a PET Mat reinforced embankment on soft ground. From this study, several outstanding discussions are found that tensile strength of reinforcement governs the failure of embankment when the soil stress is greater than failure stress. Also the optimum required tensile strength of geosynthetic reinforcement(Tos) should be determined by stress, displacement, displacement gap and safety factor of soil-PET Mat at the location of PET Mat.

• Journal of the Korean Society for Nondestructive Testing
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• v.7 no.2
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• pp.42-47
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• 1988

The off-axis tensile strength of the unidirectional carbon fiber reinforced plastic and the residual strength of impact damaged CFRP were measured and compared with the stress wave factor (SWF) of the specimens. The SWF values were measured to be decreased with the strength reduction in both cases and found to be useful for the nondestructive strength evaluation of unidirectional CFRP. The failure behaviour of the unidirectional CFRP during off-axis tensile testing was also monitored by acoustic emission(AE) method. The AE energy release showed the characteristic feature depending on the off-axis angle and this result was analyzed to be caused by the difference of the expected failure mode depending on the off-axis angle. The failure mode of CFRP was found to be analyzed by investigation of the peak amplitude distribution of AE.

• Journal of Korean Neurosurgical Society
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• v.59 no.5
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• pp.425-429
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• 2016

Objective : Rod-screw fixation systems are widely used for spinal instrumentation. Although many biomechanical studies on rod-screw systems have been carried out, but the effects of rod contouring on the construct strength is still not very well defined in the literature. This work examines the mechanical impact of straight, $20^{\circ}$ kyphotic, and $20^{\circ}$ lordotic rod contouring on rod-screw fixation systems, by forming a corpectomy model. Methods : The corpectomy groups were prepared using ultra-high molecular weight polyethylene samples. Non-destructive loads were applied during flexion/extension and torsion testing. Spine-loading conditions were simulated by load subjections of 100 N with a velocity of $5mm\;min^{-1}$, to ensure 8.4-Nm moment. For torsional loading, the corpectomy models were subjected to rotational displacement of $0.5^{\circ}\;s^{-1}$ to an end point of $5.0^{\circ}$, in a torsion testing machine. Results : Under both flexion and extension loading conditions the stiffness values for the lordotic rod-screw system were the highest. Under torsional loading conditions, the lordotic rod-screw system exhibited the highest torsional rigidity. Conclusion : We concluded that the lordotic rod-screw system was the most rigid among the systems tested and the risk of rod and screw failure is much higher in the kyphotic rod-screw systems. Further biomechanical studies should be attempted to compare between different rod kyphotic angles to minimize the kyphotic rod failure rate and to offer a more stable and rigid rod-screw construct models for surgical application in the kyphotic vertebrae.

• Journal of Global Scholars of Marketing Science
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• v.15 no.1
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• pp.61-79
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• 2005

A critical incident technique(CIT) was employed to show the results of empirical findings regarding hotel services. The major purpose of this study was to describe and analyze service failures from the customers' point of view and thus suggest strategic implications for hotel service providers. Four-hundred sixteen service failure anecdotes from hotel customers were classified using Hoffman et al.'s(1995) approach. The CIT data showed the three major categories and eleven sub-categories and revealed that, in general, tangible recovery(e.g., upgrade, free meal, discount) was more effective than intangible one(e.g., explanation, canned apology, manager's apology). Interestingly, however, sincere apology seemed to be a better recovery strategy than other types of tangible recovery. Furthermore, the results showed that severity of service failure had its own impact on customers' perception regarding hotel's service recovery efforts. In particular, irrespective of service recovery, severity of service problem was negatively related to intention to repurchase. Managerial implications and future research agenda was also discussed.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.73-83
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• 2013

Recently, not only around Korea but also other countries shows a pattern of arising high-rise building construction project which was delayed or aborted during global economic crises and recession. Although the market starts to stretch, It is getting competitive to win a contract in high-rise construction project between contractors due to lack of competitive advantage especially to Korea contractors. To get that, Korean contractors needs lifting equipment plan. But currently, they depend on the empirical methods and that cause schedule delay, not controlled cost management problem. Therefore, this research is to improve the accuracy of Lifting plan by analyzing the current issues of Lifting plan system and deducing the types of failures with planning factors, as well as analyzing the impact on schedule and cost control and safety management by each failure mode. Also, by analyzing detail risk factors per Lifting Equipment with FMEA, to infer the critical risk factor on high-rise construction project.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.214-229
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• 2021

There is an increasing need for complex and large projects to be carried out quickly. As the duration, size, and cost of the project increase, concerns about project failure are also rising. Finding factors that hinder the performance of an effective project and eliminating them in advance or controlling and managing them more effectively can be a more direct way to secure the success of the project. Previous studies have identified compositional dimensions that are classified according to attributes, covering the various obstacles that affect the success of the project through existing literature. It is a follow-up to previous research. Using DEMATEL techniques, we would like to propose to explore the appropriate measures that an entity and organization can take by identifying the causality between factors through cross-impact analysis of project disabilities and even presenting factors that may arise when they are identified. As a result of the analysis, according to the indicators to evaluate the importance, 8 factors were found to be relatively important factors, excluding the factors that Failure of project feasibility analysis and Technical environment change. In addition, 5 factors were found to be causative factors; Technical environment change, Unclarity project plan, Strategic consistency error, Inaccuracy of requirement definition, and Failure of project feasibility analysis. In contrast, the remaining 5 factors were found to be the result factors; Lack of benefits realization, Negative attitude of top management, Stakeholder conflict, Difficulty of process management, and Disturbance of communication.