• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.79-88
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• 2014

The rapid growth of complexity and scale can be witnessed in the design and development of modern systems. As such, the severity of damages in the occasional accidents has attracted great deal of attention lately. Although a variety of methods have so far been studied to overcome or reduce the disastrous results of hazards, the issues seem still persistent and even complicated due to the situation mentioned above. The concept of functional safety has been regarded as one approach to handling the matters by shifting up to the functions level from the consideration of each physical component itself. The outcomes of those efforts would be the international standards on functional safety such as IEC 61508 and its relatives including IEC 62278, EN 50128, ISO26262, and so on. In this paper, a method of how hazards can be analyzed to be coped with those standards has been studied. In the method proposed, the systems modeling language (SysML) is playing a key role to model and analyze the hazards from the viewpoint of functional safety. The approach taken has been applied in the analysis of the hazards in railroad systems. In spite of focusing on the individual components hazards, the method based on functional safety has analyzed them collectively with the added effect of identifying the cause originated from the interface between the functions.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.494-499
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• 2007

The ballast, one of a track components, plays an essential role as intermedium in transmitting train traffic-load to subgrade safely, and deterioration of ballast caused by cumulative load effects growth of track irregularity. Especially in the case of Gyeongbu high-speed railway, the deteriorating speed of ballast by dynamic vibration is faster than conventional line because KTX is longer than normal trains in length and it's velocity is very fast with high speed of 300km/h as well. In addition, ballast is a nonlinear material contrary to ordinary metal which has homogeneous property and this property of ballast may cause transformation of ballast. Therefore the theoretical modeling of ballast is quite complicated and it is hard to ensure the reliability of the result. The objective of this paper is to examine the availability of GPR(Ground Penetrating Radar) in estimating the thickness and the degree of deterioration of ballast. First, We figured out the principle of GPR which is the technique of evaluating the condition of ballast and then analyzed data which were measured at Gyeongbu high-speed railway where KTX is running now.

• Journal of Information Technology Applications and Management
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• v.23 no.1
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• pp.1-23
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• 2016

Social commerce (s-commerce) is a subset of e-commerce and uses social media for social interactions. Although s-commerce has been rapidly growing, disputes between some s-commerce firms and their consumers often occur over issues such as poor customer services, incorrect product information, and late refunds. In order for s-commerce to continuously grow, s-commerce firms need to build consumer-trust in their transaction process to minimize their consumers' uncertainty. The purpose of this study is to examine the relationships between the multidimensional trust (ability, integrity, benevolence) and the intention of continuous use of s-commerce. Moreover, this study presents antecedent factors needed for trust-building by applying the characteristics of s-commerce, and verifies the relations between the variables. We test and validate the research model and related hypotheses using structural equation modeling based on a survey done on 428 people who have previous experience with s-commerce. The result shows that trust has positive effect on the intention of continuous use, and verifies the necessity of the antecedent factors (social presence, assurance, informativeness, economic feasibility, and seller reputation) for trust-building. This study provides strategy for the continuous growth of s-commerce, and suggests theoretical implication that explains the relationship between the characteristics of s-commerce and consumers.

• Journal of the Korean Data and Information Science Society
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• v.25 no.2
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• pp.293-304
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• 2014

A child's mental health is an important element of his proper emotional development. Abuse of children by parents and peer groups are causes of depression and anxiety in children. These conditions become obstacles to their normal growth process which can be a contributing factor to juvenile delinquency. This study is based in the theoretical background of the relationship between abuse from parents and peer groups and children's emotional health. This information is analyzed through structural equation modeling.

• Knowledge Management Research
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• v.16 no.1
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• pp.117-142
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• 2015

Recently, the personal cloud computing service has been being spotlighted as an individual tool of productivity enhancement. However, compared to the rosy forecast, its diffusion rate in the domestic (Korean) market is much slower than expected. In order to find the reason for the slow growth of personal cloud computing service, we attempt to identify influencing factors on user's adoption resistance, while most prior research has focused on the factors affecting its adoption. Based on both the person-technology fit model and the privacy calculus model, we propose technostress and perceived value as key antecedents of adoption resistance. In addition, we identify (1) technical (pace of change and complexity) and personal (self-efficacy) influencing factors on technostress, and (2) beneficial (perceived mobility and perceived availability) and harmful (perceived vulnerability) influencing factors on perceived value. To validate our research model, 133 individual samples were gathered from undergraduate and graduate students who had actual experience of using at least one of personal cloud computing services. The results of the structural equation modeling confirm that both technostress and perceived value have significant effects on adoption resistance, but they have different influencing mechanisms to different types of adoption resistance (indifference, postponement, and rejection). Theoretical and practical contributions are discussed in the conclusion.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.211.1-211.1
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• 2014

Recently, the scaling of conventional planar NAND flash devices is facing its limits by decreasing numbers of electron stored in the floating gate and increasing difficulties in patterning. Three-dimensional vertical NAND devices have been proposed to overcome these issues. Atomic layer deposition (ALD) is the most promising method to deposit charge trap layer of vertical NAND devices, SiN, with excellent quality due to not only its self-limiting growth characteristics but also low process temperature. ALD of silicon nitride were studied using NH3 and silicon chloride precursors, such as SiCl4[1], SiH2Cl2[2], Si2Cl6[3], and Si3Cl8. However, the reaction mechanism of ALD silicon nitride process was rarely reported. In the present study, we used density functional theory (DFT) method to calculate the reaction of silicon chloride precursors with a silicon nitride surface. DFT is a quantum mechanical modeling method to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. The bond dissociation energy of each precursor was calculated and compared with each other. The different reactivities of silicon chlorides precursors were discussed using the calculated results.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.839-846
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• 2005

Recently broadband convergence network technology is emerging as an integrated network of telecommunication, broadcasting and Internet. But there are various threats as side effects against the growth of information technology, and malicious codes such af Internet worms may bring about confusions to upset a national backbone network. In this paper, we survey the traditional spreading models and propose a new worm spreading model on Internet environment. We also analyze the spreading effects due to tile spread period and the response period of Internet worms. The proposed model leads to a better prediction of the scale and speed of worm spreading. It can be applied to high-speed network such as broadband convergence network.

• The KIPS Transactions:PartD
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• v.13D no.6 s.109
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• pp.807-814
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• 2006

Along with the enlargement of application scope, the growth of requirements complexity, and the fast development of product for embedded system, lots of industries developing embedded software try to evolve their traditional development environment into the new paradigm such as product line engineering approach. In order to sufficiently support the evolution, software architecture is essentially required to develop the embedded software. In this paper, we propose a tool, named TToSA which translates the conventional software models to software architecture models. Our TToSA is developed with the critical implication about that an industry can approach toward the new development paradigm without the big change of the existing software development method.

• Fisheries and Aquatic Sciences
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• v.6 no.3
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• pp.149-154
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• 2003

The characteristics of pollutant loads from the various sources and seawater quality in Kwangyang Bay were evaluated. Total flow rate was estimated to be $10,868,066.8 m^3/day$ with a flow rate of R2l (the Seomjin River) as the highest one. Total COD, TN and TP loads of the input rivers and the ditches were about 27,591.8, 25,029.6 and 586.4 kg/day, respectively. Wastewater discharging loads was the greatest contributors to pollutant loads in the inner part of Kwangyang Bay. COD values in the inner part of the bay was over 3.0 mg/L, which exceeded the seawater quality criteria III of Korea. The average values of DIN and DIP were 8.62 ${\mu}gN/L\;and\;1.26\;{\mu}gP/L$, respectively. The limiting factor for algal growth was DIN. In he total discharging loads of the watershed from unit loading estimations, BOD, TN and TP were 9,132.3, 2,727.2 and 304.2 kg/day, respectively. In addition, municipal sewage by the population as pollution sources and the city of Kwangyang as administrative district had the highest loads. For a appropriate water quality recovery of Kwangyang Bay, it is suggested that it is essential to estimate reduction rate of total pollutant loads by water quality modeling.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1699-1707
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• 2013

During the fermentative production of 1,3-propanediol under high substrate concentrations, accumulation of intracellular 3-hydroxypropionaldehyde will cause premature cessation of cell growth and glycerol consumption. Discovery of oxidoreductases that can convert 3-hydroxypropionaldehyde to 1,3-propanediol using NADPH as cofactor could serve as a solution to this problem. In this paper, the yqhD gene from Klebsiella pneumoniae DSM2026, which was found encoding an aldehyde reductase (KpAR), was cloned and characterized. KpAR showed broad substrate specificity under physiological direction, whereas no catalytic activity was detected in the oxidation direction, and both NADPH and NADH can be utilized as cofactors. The cofactor binding mechanism was then investigated employing homology modeling and molecular dynamics simulations. Hydrogen-bond analysis showed that the hydrogen-bond interactions between KpAR and NADPH are much stronger than that for NADH. Free-energy decomposition dedicated that residues Gly37 to Val41 contribute most to the cofactor preference through polar interactions. In conclusion, this work provides a novel aldehyde reductase that has potential applications in the development of novel genetically engineered strains in the 1,3-propanediol industry, and gives a better understanding of the mechanisms involved in cofactor binding.