• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.151-175
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• 2015

Although three types of the information security measures (technical, physical and managerial ones) are all together critical to maintaining information security in the organizations and should be implemented at the same time, this study aims at providing theoretical basis of establishing and implementing effective managerial security measures. The rationale behind this research objective is that it is very important to effectively perform the managerial security measures to achieve the target performance level of the technical and the physical security measures because main agents of practicing the information security measures in the organizations are staff members even though the technical and the physical ones are well constructed and implemented. In particular, this study intends to develop and propose the theoretical model applicable to providing the way of improving organizational members' intention to use information security technologies since the very intention to use them is essential to effectively establishing and promoting managerial security measures. In order to achieve the objective of this study, the factors critical to influencing upon the intention to use information security technologies are derived through systematically reviewing related theories and previous studies, and then the research model and hypotheses are proposed by logically reasoning the casual relationship among the these factors. Also, the empirical analyses are performed by conducting the survey of the organization members of domestic large companies and analyzing the structural equation model by PLS (Partial Least Squares) method. The significant results of this study can contribute to expanding the research area of managerial information security and can be applied to suggesting the practical guidelines for effectively establishing and implementing the managerial security measures in various organizations.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.361-370
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• 2017

Through the use of finite element analysis and acoustic emission techniques we have evaluated the interfacial failure of a carbon fiber reinforced polymer (CFRP) repair patch on a notched aluminum substrate. The repair of cracks is a very common and widely used practice in the aeronautics field to extend the life of cracked sheet metal panels. The process consists of adhesively bonding a patch that encompasses the notched site to provide additional strength, thereby increasing life and avoiding costly replacements. The mechanical strength of the bonded joint relies mainly on the bonding of the adhesive to the plate and patch stiffness. Stress concentrations at crack tips promote disbonding of the composite patch from the substrate, consequently reducing the bonded area, which makes this a critical aspect of repair effectiveness. In this paper we examine patch disbonding by calculating the influence of notch tip stress on disbond area and verify computational results with acoustic emission (AE) measurements obtained from specimens subjected to uniaxial tension. The FE results showed that disbonding first occurs between the patch and the substrate close to free edge of the patch followed by failure around the tip of the notch, both highest stress regions. Experimental results revealed that cement adhesion at the aluminum interface was the limiting factor in patch performance. The patch did not appear to strengthen the aluminum substrate when measured by stress-strain due to early stage disbonding. Analysis of the AE signals provided insight to the disbond locations and progression at the metal-adhesive interface. Crack growth from the notch in the aluminum was not observed until the stress reached a critical level, an instant before final fracture, which was unaffected by the patch due to early stage disbonding. The FE model was further utilized to study the effects of patch fiber orientation and increased adhesive strength. The model revealed that the effectiveness of patch repairs is strongly dependent upon the combined interactions of adhesive bond strength and fiber orientation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.979-988
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• 2012

The 3D structure of GDL for fuel cells was measured using high-resolution X-ray tomography in order to study material transport in the GDL. A computational algorithm has been developed to remove noise in the 3D image and construct 3D elements representing carbon fibers of GDL, which were used for both structural and fluid analyses. Changes in the pore structure of GDL under various compression levels were calculated, and the corresponding volume meshes were generated to evaluate the anisotropic permeability of gas within GDL as a function of compression. Furthermore, the transfer of liquid water and reactant gases was simulated by using the volume of fluid (VOF) and pore-network model (PNM) techniques. In addition, the simulation results of liquid water transport in GDL were validated by analogous experiments to visualize the diffusion of fluid in porous media. Through this research, a procedure for simulating the material transport in deformed GDL has been developed; this will help in optimizing the clamping force of fuel cell stacks as well as in determining the design parameters of GDL, such as thickness and porosity.

• Applied Microscopy
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• v.36 no.2
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• pp.83-91
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• 2006

The number and structure of synapses are dynamically changed in response to diverse physiological and pathological conditions. Since strength of synaptic transmission is closely related to the synaptic density on a neuron, both synaptogenesis and synapse loss may play important roles in controlling neuronal activity. Thus it is essential to estimate the number of synapses using an accurate quantitative method for better understanding of the numerical alteration of synapses under terrain experimental conditions. We applied physical disector principle to estimating the number of synapses per neuron in the dentate gyrus of adult mice. First, we measured the numerical density of granule cells using the physical disector principle. Second, the density of medial perforant path to granule cell synapses was estimated using the bidirectional physical disector. Then, the volume ratio of molecular layer to granule cell layer was measured. With these numerial values, we successfully calculated the number of synapses per neuron. Individual granule cells have approximately 6500 synapses in the dentate gyrus of adult mice $(6,545{\pm}330)$, which are comparable to those of other researchers. Our results showed that the estimation of synapse numbers per neuron using the physical disector principle would provide accurate and precise information on the numerical alteration of synapses in diverse physiological and pathological conditions. Following analyses of synapse numbers using this method will contribute to the better understanding of structural synaptic plasticity in a variety of experimental animal models.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.1009-1017
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• 2004

Sialyltransferases cloned so far show the remarkable tissue-specific expression, which is correlated with the existence of cell type-specific sialylated sugar structure in glycoconjugates. In the previous studies, we found various mRNA isoforms of human sialyltransferases generated by alternative splicing and alternative promoter utilization. To understand the regulatory mechanisms for specific expression of human sialyltransferase genes and for production of their mRNA isoforms, in this study, we have isolated and characterized five kinds of human sialyltransferase genes: hST3Gal II, hST8Sia II, hST8Sia III, hST8Sia IV, and hST8Sia V. The hST3Gal II gene is composed of six exons, which span over 17kb, with exons ranging in size from 46 to over 1017 bp. The hST8Sia III gene comprises over 10 kb, and consists of only four exons, which is much smaller and simpler than other human sialyltransferase genes. In contrast, three genes (hST8Sia II, hST8Sia IV and hST8Sia V) span more than 70 kb, and comprise five or more exons. All exon-intron boundaries follow the GT-AG rule. In particular, the sialylmotif L, which is a highly conserved region in all cloned sialyltransferases, was found in one exon of hST8Sia III, whereas this motif is encoded by discrete exons in the other human sialyltransferases. Exon structures of these sialyltransferase genes show the structural diversity, as found in other human sialyltransferase genes reported so far. We determined the transcription start site of hST3Gal II gene by the 5'-RACE and cap site hunting experiments.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.46-51
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• 2015

Stainless steel is a popular structural materials for liquid-hydrogen storage containers and piping components for transporting high-temperature fluids because of its superior material properties such as high strength and high corrosion resistance at elevated temperatures. In general, tungsten inert gas (TIG) arc welding is used for bonding stainless steel. However, it is often reported that the thermal fatigue cracks or initial defects in stainless steel after welding decreases the reliability of the material. The objective of this paper is to clarify the characteristics of ultrasonic guided wave propagation in relation to a change in the initial crack length in the welding zone of stainless steel. For this purpose, three specimens with different artificial defects of 5 mm, 10 mm, and 20 mm in stainless steel welds were prepared. By considering the thickness of s stainless steel pipe, special attention was given to both the L(0,1) mode and L(0,2) mode in this study. It was clearly found that the L(0,2) mode was more sensitive to defects than the L(0,1) mode. Based on the results of the L(0,1) and L(0,2) mode analyses, the magnitude ratio of the two modes was more effective than studying each mode when evaluating defects near the welded zone of stainless steel because of its linear relationship with the length of the artificial defect.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.189-194
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• 2015

P450 1A2 is responsible for the metabolism of clinically important drugs and the metabolic activation of environmental chemicals. Genetic variations of P450 1A2 can influence its ability to perform these functions, and thus, this study aimed to characterize the functional significance of three P450 1A2 allelic variants containing nonsynonymous single nucleotide polymorphisms (P450 $1A2^*8$, R456H; $^*15$, P42R; $^*16$, R377Q). Variants containing these SNPs were constructed and the recombinant enzymes were expressed and purified in Escherichia coli. Only the P42R variant displayed the typical CO-binding spectrum indicating a P450 holoenzyme with an expression level of ~ 170 nmol per liter culture, but no P450 spectra were observed for the two other variants. Western blot analysis revealed that the level of expression for the P42R variant was lower than that of the wild type, however the expression of variants R456H and R377Q was not detected. Enzyme kinetic analyses indicated that the P42R mutation in P450 1A2 resulted in significant changes in catalytic activities. The P42R variant displayed an increased catalytic turnover numbers ($k_{cat}$) in both of methoxyresorufin O-demethylation and phenacetin O-deethylation. In the case of phenacetin O-deethylation analysis, the overall catalytic efficiency ($k_{cat}/K_m$) increased up to 2.5 fold with a slight increase of its $K_m$ value. This study indicated that the substitution P42R in the N-terminal proline-rich region of P450 contributed to the improvement of catalytic activity albeit the reduction of P450 structural stability or the decrease of substrate affinity. Characterization of these polymorphisms should be carefully examined in terms of the metabolism of many clinical drugs and environmental chemicals.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.611-620
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• 2007

The beam-column connection is the critical design section of general steel frame structures owing to the behavioral characteristics of the structural system. As most members of a frame structure are composed of rolled section beams, the cross-section of the beam members is governed by the negative bending moment near beam-column connections. Such a design concept leaves a redundant load-carrying capacity at the positive bending regions of the beam members leading to design inefficiency. Therefore, it is of utmost importance to redistribute the beam end moments and reduce the stresses at the beam-column connections for a more efficient design of steel frame structures. In this study, reaction-moment prestressing method (RMPM) was proposed for the innovative design and construction of steel frame structures. The RMPM is a prestressing method utilizing the elastic bending deformation of a beam member induced by temporary prestressing for the distribution of a relatively large bending moment to other sections for the efficient use of the beam section. By the application of the RMPM, the negative bending moment at the beam-column connections can be significantly reduced, ultimately leading to possible use of smaller beam sections. Through a series of model tests and numerical analyses of steel frame structures, the moment distributing effect and feasibility of the RMPM was verified.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.368-376
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• 2010

The bent foundation with single drilled shafts is suitable and economical in South Korea, which has good rock in a shallow depth. This foundation has been designed with an elastic design concept. To apply a plastic design concept written in Korea Bridge Design Criteria, a detail design regulation, which includes the method for a plastic hinge point to occur above the ground, rebar arrangement and soil modelling, should be defined. Soil modelling should be considered in the respect of structural engineer's practicality. In this paper, single drilled shaft piers with 1m diameter are constructed, and cyclic lateral load tests loaded at 4m above the ground are taken to examine the behavior. Reduced diameter shaft above the ground and remaining the steel casing under the ground were used to induce plastic hinge to occur above the ground. Simplified soil models such as elastic relation and p-y curve are adapted, and the prediction results are compared with test results. Prediction results of a model bridge were compared according to soil models with time domain analyses, and design criteria of soil were proposed.

• Management & Information Systems Review
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• v.28 no.4
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• pp.109-129
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• 2009

This study aims at investigating the effectiveness of SME's R&D system empirically. Specifically, this study analyze the relationships among R&D inputs(R&D investment, R&D human resource management), process(R&D planning, external network, internal cooperation), and output(technological innovation). A questionnaire was developed to measure the above variables. To test these relations, data were collected from the small and medium-sized IT firms located in Daegu-Kyungbuk region. The survey data of 154 firms were integrated as the empirical base for testing the relations. Most respondents were from the managers. Structural equation modeling analyses were used to examine the relations. Major results are as follows: Firstly, R&D HRM was positively and significantly influenced on the R&D planning. Secondly, R&D planning was positively and significantly affected on the external network, internal cooperation, and technological innovation. Thirdly, the both relations between R&D investment and R&D planning, and external network and technological innovation were not significant statistically. These results suggest the following implications. First, R&D human resource management is very important for IT SMEs. Secondly, internal cooperation mediates R&D inputs and technological innovation by approaching the other department's unique resources and by sharing the cost of new resource development. Several future researches need to overcome the limitations of this research. First, this study's sample was based on the small and medium-sized IT firms just located in Daegu-Kyungbuk region. This limitation may imply that empirical results can not represent overall small and medium-sized firm's situations. Therefore, future research needs to include different samples. Secondly, this study depends on the latitudinal study.