• Journal of the Microelectronics and Packaging Society
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• v.13 no.3 s.40
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• pp.1-8
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• 2006

Higher density integration and adoption of new materials in advanced electronic package systems result in severe electrochemical reliability issues in microelectronic packaging due to higher electric field under high temperature and humidity conditions. Under these harsh conditions, metal interconnects respond to applied voltages by electrochemical ionization and conductive filament formation, which leads to short-circuit failure of the electronic package. In this work, in-situ water drop test and evaluation of corrosion characteristics for SnPb solder alloys in D.I. water and NaCl solutions were carried out to understand the fundamental electrochemical migration characteristics and to correlate each other. It was revealed that electrochemical migration behavior of SnPb solder alloys was closely related to the corrosion characteristics, and Pb was primarily ionized in both D.I. water and $Cl^{-}$ solutions. The quality of passive film formed at film surface seems to be critical not only for corrosion resistance but also for ECM resistance of solder alloys.

• Korean journal of communication and information
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• v.30
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• pp.121-141
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• 2005

Most of the convergence studies argue the reform of the current policy regime of broadcasting and telecommunications in Korea from two perspectives: 1) the media governance perspective and 2) the media industry perspective. The former emphasizes the need of integrity, consistency and efficiency of the regime in the convergence environment, while the latter focuses upon the growth and development of the media industry making the best of economic and industrial opportunities that are spawned by digital convergence. Although their arguments are logical and robust, they are lopsided in terms of legalism and myopic economism due to the linear perception of institutionalism, Bureaucratic administrative practices as well as ostentatious IT policies that have chronically plagued the policy regime in Korea cannot be resolved by simply assimilating distinct regulatory bodies and laws. Unless these two issues are properly addressed, the convergence of media policy institutions would end up a half-success or half-failure contrary to the exportations of existing studies.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1417-1425
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• 2014

The selection of morphologically normal spermatozoa is critical to obtain high breeding performances in boar breeding farms and artificial insemination (AI) centers. Parameters for the selection of semen mainly include total sperm motility, concentration, and morphology. However, these primary parameters are often not reliable for discriminating between normal and abnormal, non-fertilizable spermatozoa. The present study was designed to compare the motion characteristics, fertilization ability using in vitro fertilization (IVF), and acrosome formation of the semen from boars having low (boar number 2012) and normal (boar number 2004 and 2023) breeding performances. The ultimate goal was to identify additional simple and easy criteria for the selection of normal sperm. There was no significant difference between boar 2004 and boar 2023 sperm total motility in computer assisted sperm analysis. However, boar number 2012 semen presented a significantly reduced population of rapid moving spermatozoa and an increased population of slow moving spermatozoa compared to boar numbers 2004 and 2023. Analysis of detailed motion characteristics revealed that sperm from boar number 2012 had significantly reduced motility in progressiveness, average path velocity, straight-line velocity (VSL), curvilinear velocity (VCL), straightness, and linearity. The assessment of the fertilizing ability by IVF also showed that sperm from boar number 2012 showed a fertility rate of 3.4%, whereas sperm from boar number 2023 had a fertility rate of 75.45%. Interestingly, most of the sperm nuclei were found on the peripheral area of the oocytes, suggesting that the sperm from boar number 2012 lacked penetration ability into the oocyte zonapellucida. The acrosome formation analysis using Pisum sativum agglutinin staining demonstrated that the sperm from boar number 2012 had a defect in acrosome formation. Consequently, primary parameters for selecting semen before AI such as motility are not sufficient to select normal and fertilizable spermatozoa. In conclusion, the present study suggests that the acrosome staining and detailed motion characteristics such as progressiveness, VCL, and VSL should be included in determining semen quality together with primary parameters for successful AI and high breeding performance in the swine industry.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.127-140
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• 2015

A fault is one of the critical factors that may lead to a possible ground collapse occurring in construction site. A fault core, however, possibly acting as a failure plane in whole fault zone, is composed of fractured rock and gouge nonuniformly distributed and thus can be characterized by its wide range of shear strength which is generally acquired by experimental method for stability analysis. In this study, we performed direct shear test and grain size distribution analysis for 62 fault core samples cropped from 12 different spots located in the vicinity of Kyongju and Ulsan, Korea. As a result, the range of shear strength representing the characteristics of fault cores in the study regions is determined with regard to vertical stress using a regression analysis for experiment data. The weight ratio of gravels in the samples is proportional to the shear strength and that of silt and clay is in inverse proportion to the shear strength. For most samples, the coefficient of determination is over 0.7 despite of inhomogeneity of them and consequently we determined the lower limit and upper limit of the shear strength with regard to the weight ratio by setting the confidence interval of 95%.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.36-50
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• 2005

e-Learning has been mushrooming with wide range of learning groups from pedagogy to andragogy. Despite of increasing e-learning opportunities, many people doubt whether e-learning learners really learn something. The related research papers emphasized that e-Learning would be a failure in terms of understanding of e-learners and intuitive learning activities for activating learner's long-term memory span. The current learning strategies in e-Learning may be based on the traditional classroom, and this results in boring and ineffective learning outcomes. This paper analyzed that how learners have received e-Learning for the last few years from the research and explained what could be the failing aspects of e-Learning. To be successful, e-Learning should consider the e-Learner's individualized teaming style and thinking patterns. When considering of various e-Learning components, the quality of e-learning should not be focused on any specific single factor, but develop every individual factor to the high level of quality. In conclusion, this paper suggest that we need new understand of e-Learning and e-Learner. Also the e-Learning strategies should be examined throughly whether they are on the side of learners and realized how they learn from e-Learning. Finally, we should add enormous imagination into e-Learning for next generation because their teaming patterns significantly differ from their parent's generation.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.989-998
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• 2018

Connectivity between water source and demand node can be served as a critical system performance indicator of the degree of water distribution network (WDN)' failure severity under abnormal conditions. Graph theory-based approaches have been widely applied to quantify the connectivity due to WDN's graph-like topological feature. However, most previous studies used undirected-unweighted graph theory which is not proper to WDN. In this study, the directed-weighted graph theory was applied for WDN connectivity analyses. We also proposed novel connectivity indicators, Source-to-Node Shortest Pathway (SNSP) and SNSP-Degree (SNSP-D) which is an inverse of the SNSP value, that does not require complicate hydraulic simulation of a WDN of interest. The proposed SNSP-D index was demonstrated in total 42 networks in J City, South Korea in which Pearson Correlation Coefficient (PCC) between the proposed SNSP-D and four other system performance indicators was computed: three resilience indexes and an energy efficiency metric. It was confirmed that a system representative value of the SNSP-D has strong correlation with all resilience and energy efficiency indexes (PCC = 0.87 on average). Especially, PCC was higher than 0.93 with modified resilience index (MRI) and energy efficiency indicator. In addition, a multiple linear regression analysis was performed to identify the system hydraulic characteristic factors that affect the correlation between SNSP-D and other system performance indicators. The proposed SNSP is expected to be served as a useful surrogate measure of resilience and/or energy efficiency indexes in practice.

• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.119-128
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• 2010

In the shipbuilding industry, due to the global trends where the number of IT (Information Technology) devices of a smart ship have been increased rapidly, the need to develop a new shipboard backbone network has recently emerged for integrating and managing the IT devices of a smart ship efficiently. A shipboard backbone network requires high survivability because it is constructed in automatic and unmanned smart ships where a failure of the backbone network can cause critical problems. The purpose of this paper thus is to study SAN (Ship Area Network) as a efficient shipboard backbone network, considering particularity of shipboard environment and requirement of high survivability. In order to do so, we designed a dual network topology that all network nodes, including the IT devices installed in a smart ship, are connected each other through dual paths, and reuding tht IT devices pnstalles supporices network survivability as well as t Iffic efficiency for the dual network topology. And then, we verified the performance of the suggested SAN by theoretical and practical analysis including the graph theory, the probability theory, implemental specifications, and computer simulations.

• Journal of Distribution Science
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• v.11 no.4
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• pp.37-49
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• 2013

Purpose - This research identifies the meaning of the core capability level of Car Master and the reason why its service at the Moment of Truth should be demonstrated through empirical cases. It can be seen that this study differs from existing research because it proposes that the recognized core capability level to achieve customer satisfaction should focus on the mediating effect of Moment of Truth quality. This paper examines the effect of Car Master's recognized core capability level on customer satisfaction by using the variables mentioned above. Moreover, this study uses regression analysis to verify that the mediating effect of Moment of Truth quality on Car Master's capability level achieves customer satisfaction. Research design, data, and methodology - First, we present evidence that could apply to Car Master's recognized core capability level by detailing the relationship between customer satisfaction and a structuring factor for Car Master's core capability level. Our proposed research model observes the relationship between the structuring factor of core capability and customer satisfaction. Second, we had an opportunity to define how the core capability and Moment of Truth quality affect customer satisfaction by performing empirical analysis on the partial mediating effect of Moment of Truth quality at a recognized core capability level and Moment of Truth quality affecting customer satisfaction. Results - First, the results indicate that Car Master's recognized core capability level (product professionalism, marketing skill, and reliability) positively affects customer satisfaction. Second, the results show that an ability to listen and a sense of dedication positively affect customer satisfaction, and are among the Moment of Truth quality factors; but performance capability, which is one of the Moment of Truth quality factors, does not positively affect customer satisfaction. These results clearly differ from prior studies focused on Moment of Truth quality and consumer satisfaction. Third, the results show that Moment of Truth quality has a partial mediating effect in terms of the impact of Car Master's recognized core capability level in achieving consumer satisfaction. Conclusions - This research indicates that the company will be able to expand if they investigate and show an interest in more training and education for Car Master. The study verified that outstanding Car Masters show differentiated performance on customer satisfaction at the Moment of Truth in various instances. Thus, we believe that this is the time for a discussion on systematic and empirically recognized core capability levels and the Moment of Truth quality. The study on Car Master's recognized core capability level offers suitable solutions for Car Masters to respond to customers at the Moment of Truth. Further, this study emphasizes the importance of service as a critical factor having a direct relationship with the company's success and failure and contributing to building trust with the customer. Thus, an investment in continuous education and training for Car Master will help the growth of the business.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.47-60
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• 2010

This study is focused on the analysis of tunnel behavior to estimate the stability on tunnel design. An estimation method was proposed as a hybrid consideration, which contains the displacement analysis by 3D numerical simulation, the maximum displacement obtained after field measurement, and an assessment of tunnel stability using a deformation analysis proposed by Sakurai(1988, 1997). The points of case study by Sakurai(1988, 1997) were replotted considering his analysis. From the new analysis of the tunnel case study, the trend line for analyzed points is analogized, which curve is divided into stable, unstable and failure zone. To evaluate the estimation method, a special shape of railway tunnel was selected, which are the Inchon international airport rail way connected to subway line 9 in Gimpo, Korea. The point s of upper and below track on the Inchon international airport rail way were satisfied to the stability of tunnel after reinforcing. Also the points shows the higher apparent Young's modulus, which resulted from improvement on shear strength by the micro silica grouting and the supporting of umbrella method. Therefore, if new analysis used, proper tunnel reinforcing method could be selected according to tunnel strain and geological property.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.187-187
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• 2009

Opening of fractures induced by shear dilation or normal deformation can be a significant source of fracture permeability change in fractured rock, which is important for the performance assessment of geological repositories for spent nuclear fuel. As the repository generates heat and later cools the fluid-carrying ability of the rocks becomes a dynamic variable during the lifespan of the repository. Heating causes expansion of the rock close to the repository and, at the same time, contraction close to the surface. During the cooling phase of the repository, the opposite takes place. Heating and cooling together with the, virgin stress can induce shear dilation of fractures and deformation zones and change the flow field around the repository. The objectives of this work are to examine the contribution of thermal stress to the shear slip of fracture in mid- and far-field around a KBS-3 type of repository and to investigate the effect of evolution of stress on the rock mass permeability. In the first part of this study, zones of fracture shear slip were examined by conducting a three-dimensional, thermo-mechanical analysis of a spent fuel repository model in the size of 2 km $\times$ 2 km $\times$ 800 m. Stress evolutions of importance for fracture shear slip are: (1) comparatively high horizontal compressive thermal stress at the repository level, (2) generation of vertical tensile thermal stress right above the repository, (3) horizontal tensile stress near the surface, which can induce tensile failure, and generation of shear stresses at the comers of the repository. In the second part of the study, fracture data from Forsmark, Sweden is used to establish fracture network models (DFN). Stress paths obtained from the thermo-mechanical analysis were used as boundary conditions in DFN-DEM (Discrete Element Method) analysis of six DFN models at the repository level. Increases of permeability up to a factor of four were observed during thermal loading history and shear dilation of fractures was not recovered after cooling of the repository. An understanding of the stress path and potential areas of slip induced shear dilation and related permeability changes during the lifetime of a repository for spent nuclear fuel is of utmost importance for analysing long-term safety. The result of this study will assist in identifying critical areas around a repository where fracture shear slip is likely to develop. The presentation also includes a brief introduction to the ongoing site investigation on two candidate sites for geological repository in Sweden.