• Journal of Information Technology Applications and Management
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• v.19 no.2
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• pp.59-78
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• 2012

The purpose of this longitudinal case study is to shed light on the reliability problems of IS performance evaluation by analyzing the discrepancy between ex ante evaluation in 2011 and ex post evaluation in 2012. Through an information system development project of a public enterprise, the gap between ex ante and ex post evaluation was ascertained and the causes as to why such gap occurs and the success factors that can solve the problems were derived. The ex ante evaluation of IS performance was performed based on both IS success model and BSC model and the ex post evaluation was carried out at the time after the target system has been built up by applying the evaluation measures and process that are similar to the ex ante evaluation. In the ex ante evaluation the business performance improved by the target system was estimated to 18.2%. On the other hand, it was seen as being low at 15.2% in the ex post evaluation and the differences were found to be statistically significant in 6 out of 10 measures. The reasons as to why such gap occurs were diagnosed as being of 2 types : (1) changes in the evaluation psychology according to the differences in the evaluation objectives; and (2) excessive expectation levels of the target system that is formed at the time of the ex ante evaluation. In other words, the users who have excessive expectations tend to overestimate in the ex ante evaluation and, in the ex post evaluation, tend to underestimate lower than the actual performance mainly due to disappointment on the results that do not meet the early expectations. As solutions to overcome the reliability problem of ex ante evaluation, 3 factors were derived : (1) the temperance of excessive expectation levels of the users; (2) a clear definition of the scope and functionality of the target system; and (3) actual commitments for the evaluations of IT performance.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.48-55
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• 2014

Many techniques are available for destructive and nondestructive measurement of mechanical hardness. The ultrasonic method could be widely applicable as a nondestructive technique. Many studies have examined how changes in the mechanical hardness affect the longitudinal velocity of ultrasonic waves. This approach aims to estimate the overall velocity variations in specimens. However, proper nondestructive examination techniques are needed as effective tools for analyzing the effects of heat treatment on the surface of the specimens. Therefore, in this study, the effect on the hardness of piston rods was nondestructively measured using surface ultrasonic waves. The hardness after heat treatment was investigated at various depths in the specimens, and the velocity of the surface ultrasonic waves was measured with respect to the hardness of the piston rods. In addition, finite element method simulations were performed to confirm the behavior of the waves.

• Applied Microscopy
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• v.21 no.2
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• pp.1-13
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• 1991

In order to investigate the factors of the control mechanism of somitogenesis, early chick embryos (H-H stage $8{\sim}13$) were treated with heat shock, ${\alpha}$-amanitin and cycloheximide and morphological changes of somite were examined by light microscopy, transmission and scanning electron microscopy. In normal chick embryo, somites were formed from the somitomere which preexisted in segmental plate. Somites were wrapped with extracellular collagen fibrils and connected with neural tube, notochord and ectoderm. And then, somites were differentiated to sclerotome, dermatome and myotome by the interaction of nervous tissue. Abnormal somites were observed after formation of six or seven so mites in heat shock treated group. Amounts of collagen fibrils were obviously decreased in this group. In cycloheximide treated group, most so mites were smaller and neural tube formation was incomplete. Chromatins were condenced and formed several heterochromatins in the nucleus of somite cells. Lipid like cytoplasmic dense mass and lipid droplets were also observed. Segmentation of somites seemed to be normal progress in ${\alpha}$-amanitin treated group. Center of somite, however, hollowed in longitudinal sectioned samples. These results suggested that so mites were already existed in the segmental plate as the form of somitomere. Segmented somites were contacted with neural tube or notochord and the somites were tightly connected with each other by the extracellular collagen fibrils which were secreted from neuroepithelium and somite cells. Somites are thought to differentiate into sclerotome, dermatome and myotome by these interactions.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.92-97
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• 2008

Salt wedge into the river from the sea or fresh water flume (fresh wedge) in the ocean from the sea has density current characteristics. However, when temperature and salinity simultaneously determine the density of wedges, one of salinity and temperature can distributed in the reversed profiles against gravity, even though the density profile is stable. In this case, the double diffusive process is critical in determining mixing rate. The present work studies relative contribution of shear driven mechanical mixing component and double diffusive layering process, when warm salty denser water is introduced into the cold fresh lighter water column. Laboratory experiment releases warm salty denser water into cold fresh lighter water controlling discharge amount to achieve the steady state of density current. When longitudinal density rate becomes 15, the released amount ratio of salt and heat changes sharply and in the releasing point, vigorous mixing occurs with increase of discharged amount due to double diffusion. Double diffusion distabilizes gravitational stability and enhances the mixing rate up to $6{\times}10$ times at the lower density ratio comparing to the higher density ratio.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.178-181
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• 2010

Purpose: Retronychia is the embedding of the nail into proximal nail fold. Retronychia starts with disruption of the longitudinal growth of the nail. With the growth of a new nail, the old one is pushed upwards and backwards. This leads to embedding of the top nail into the ventral aspect of the proximal nail fold and results with chronic paronychia. We present a case of retronychia that was rarely reported in the literature. Methods: A 46-year old female presented with a 3-month history of painful right first, 2nd, 3rd toenail changes. Although she was initially treated with broad spectrum antibiotics, she did not response to therapy. Later, she presented to our department because of progressively worsening pain that impaired her walking. Physical examination revealed with proximal nail fold erythema, painful swelling, yellowish nail discoloration, and distal onycholysis. Bacterial and fungus culture showed no organism. Treatment was surgical nail avulsion under local anesthesia. Results: The postoperative course was uneventful. 10 months later, the patient had a normal growing nail and was free of symptoms. Conclusion: We report a case of retronychia on toenail. Retronychia is a proximal nail plate ingrowth into the proximal nail fold which is associated with multiple generations of nail plate misaligned beneath the proximal nail. Management consisted of simple avulsion of superimposed nail. Retronychia is suspected with a persistent paronychia, particularly in the setting of trauma. Avulsion of the top nail confirms the diagnosis and may be curative if the underlying nail appears healthy.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.26-31
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• 2005

The strong continuous fiber reinforced metal matrix composites (MMCs) are recently used in aerospace and transportation applications as an advanced material due to its high strength and light weight. Unidirectional fiber-metal matrix composites have superior mechanical properties along the longitudinal direction. However, the applicability of continuous fiber reinforced MMCs is somewhat limited due to their relatively poor transverse properties. Therefore, the transverse properties of MMCs are significantly influenced by the properties of the fiber/matrix interface. In order to be able to utilize these MMCs effectively and with safety, it must be determined their elastic plastic behaviors at the interface. In this study, the interfacial stress states of transversely loaded unidirectional fiber reinforced metal matrix composites investigated by using elastic-plastic finite element analysis. Different fiber volume fractions $(5-60\%)$ were studied numerically. The interlace was treated as three thin layer (with different properties) with a finite thickness between the fiber and the matrix. The fiber is modeled as transversely isotropic linear-elastic, and the matrix as isotropic elastic-plastic material. Using proposed model, the effects of the interface region and fiber arrangement in MMCs on the distributions of stress and strain are evaluated. The stress distributions of a thin multi layer interface have much less changes compared with conventional perfect interface. The analyses were based on a two-dimensional generalized plane strain model of a cross-section of an unidirectional composite by the ANSYS finite element analysis code.

• Childhood Kidney Diseases
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• v.10 no.2
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• pp.192-200
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• 2006

Purpose : This study was performed to identify longitudinal changes in the prevalence of organisms isolated from urinary tract infection(UTI) and in the pattern of Escherichia coli susceptibility to antibiotics during the past 10 years in children with UTI. Methods : We performed a retrospective study of a total of 192 urine cultures from children with UTI in the Department of Pediatrics, Seoul Adventist Hospital over two periods(1st: 1995-2000, 2nd:2001-2005). Antimicrobial susceptibility of the isolates was compared between the two groups. Results : The pathogens of UTI in the two groups were similar. In the first period, E. coli was the leading uropathogen(66.2%) followed by Klebsiella pneumoniae(7.8%), Enterobacter cloacae(6.5%), and others(19.5%). In the second period, E. coli was the leading uropathogen(67%) followed by K. pneumoniae(12.2%), E. cloacae(3.5%), Enterobacter aerogenes(3.5%), and others(13.8%). The susceptibility pattern of E. coli to amoxicillin/clavulanate(87.5%, 81.0%) did not present any statistically significant difference between the two periods(P>0.05). The susceptibility of E. coli to TMP/SMX(52.4%, 50.0%) was still low with no significant difference between the two periods(P>0.05). Conclusion : Our results suggest that the use of amoxicillin/clavulanate is still an excellent therapeutic option in children with UTI. The low rate of susceptibility to TMP/SMX against uropathogens suggest that TMP/SMX may be reevaluated as the first-line therapeutic drug for UTI.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.94-101
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• 2003

The pressure tubes made of cold-worked Zr-2.5Nb alloy are subjected to creep deformation during service period resulting in changes to their geometry such as longitudinal elongation, diameter increase and sagging. To evaluate integrity of them, information on the material creep property of the serviced tubes is essential. As one of the methods with which the creep property is directly measured from the serviced components, small punch(SP) creep testing has been considered as a substitute for the conventional uniaxial creep testing. In this study, applicability of the SP creep testing to Zr-2.5Nb pressure tube alloy was studied particularly by measuring the power law creep constants, A, n. The SP creep test has been successfully applied fur other high temperature materials which have isotropic behavior. Since the Zr-2.5Nb alloy has anisotropic property, applicability of the SP creep testing can be limited. Uniaxial creep tests and small punch creep tests were conducted with Zr-2.5Nb pressure tube alloy along with finite element analyses. Creep constants obtained by each test method are compared. It was argued that the SP creep test result gave results reflecting material properties of both directions. But the equations derived in the previous study for isotropic materials need to be modified. Discussions were made fur future research directions for application of the SP creep testing to Zr-2.5Nb tube alloy.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.1941-1955
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• 2009

This study compares street fashions in Korea and Japan to investigate possible interactive influences. Women's street fashion data were obtained from two magazines in each country from the 2003 spring/summer season to the 2007/08 fall/winter season. A total of 2211 pictures were used in the final analysis. The longitudinal changes in street fashion showed a similar trend toward full coordination, the increased use of colors and prints, and the influences of global fashion trends in both countries. The results showed a time lag between the two countries in the adoption of some clothing items that suggest the influence of Japanese street fashion in Korea. The time lag has diminished and since 2006, street fashion has simultaneously progressed under the mutual and common influences of global trends. There are more fashion similarities in the spring/summer than in fall/winter. The adoption of fashion accessories did not show any sign of a time lag and many accessories became popular during the same season.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.567-573
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• 2008

Water quality in the longitudinal and cross section was measured and analyzed at Dal stream. The change of water quality was compared with the change of discharge at the important points. When discharge was increased by rainfall, the concentration of BOD was decreased and the concentrations of TN and TP were increased. The correlation coefficient of BOD, TN, TP showed large with the water velocity and depth in the Case 2 that discharge was increased. Rainfall had much influenced in water quality because of moving the nonpoint source to the channel. Water velocity was analyzed by numerical model(Surface water Modeling System). Velocity was comparatively fast in the upstream that had a steep slope and narrow channel. The characteristics of pollution transfer was simulated in 2-dimensional channel, the pollution diffused rapidly to the center of flow in the main channel. Flow had much influenced in diffusion of pollution.