• Journal of the korean society of oceanography
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• v.32 no.3
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• pp.112-119
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• 1997

Coastal sediments collected near the Youngkwang Nuclear Power Plant were analysed for major(Al$_2$O$^_3$, Fe$^_2$O$^_3$, MgO, CaO, Na$^_2$O, K$^_2$O, TiO$^_2$, MnO), trace (Ba, Sr, V, Co, Cr, Cu, Ni, Zn, Pb) metal, and P$^_2$O$^_5$ contents. The composition of bulk metals from most stations fits within the range as those in the average crustal and sedimentary rocks, suggesting that the anthropogenic perturbation of these components is insignificant. The abundance and distribution of total contents for the majority of metals in the surface sediment could be explained by the grain size and were associated with mud (<63 ${\mu}$m) contents. However, distributions of Ca, K, Sr and Ba did not have any significant association with the sediment grain size. This may be due to the geochemical coherence among these metals in certain minerals abundant in coarse grained fractions. The distribution of Pb appears to be partly affected by the contribution from aerosol fallout. Using the R'-mode factor analysis, we show that the variance of the metal contents could be explained by four factors which account for 93.7% of the total variance. It appears that texturally controlled and/or sorting factors influenced by fine fraction are the most dominant factors which determine the relative abundance and distribution of metals in the study area.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.831-836
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• 2000

During machining, since more than 50% compliance of the cutting point in machine tool structures comes from headstocks, with the remainder coming from beds, slides and structural joints, the structural analysis of the headstock is very important to improve the static and dynamic performances. Especially, in case of machining hard and brittle materials such as glasses and ceramics with the grinding machine, the reinforced headstock with the high damping material is demanded. Since the fiber reinforced composite materials have excellent properties for structures, owing to its high specific modulus, high damping and low thermal expansion, it is expected that the dynamic and thermal characteristics of the headstock will be improved if they are employed as the materials fur headstock. In this paper, the design and the manufacturing methods as well as the static and dynamic characteristics of a steel-composite hybrid headstock were investigated analytically and experimentally to improve the performance of the grinding machine system.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1819-1829
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• 2018

A three-phase, three-switch, and three-level boost-type PWM rectifier (Vienna rectifier) is proposed as an active front-end power factor correction (PFC) rectifier for telecom loads. The proposed active front-end PFC rectifier system is modeled by the switching cycle average model. The relation between duty ratios and DC link capacitor voltages is derived in terms of the system input currents. Furthermore, the feasible switching states are identified and applied to the proposed system to reduce the switching stress and DC ripples. A detailed equivalent circuit analysis of the proposed front-end PFC rectifier is conducted, and its performance is verified through simulations in MATLAB. Simulation results are verified using an experimental setup of an active front-end PFC rectifier that was developed in the laboratory. Simulation and experimental results demonstrate the improved power quality parameters that are in accordance with the IEEE and IEC standards.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.531-534
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• 2004

In Recent, it became necessary to develope the technology about electrodeless fluorescent lamp according to demand of the electodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electordeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter. So it is of the utmost importance to design antena and inverter Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electordeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.441-447
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• 2002

KSR-III(Korea Sounding Rocket - III), which is being developed by Space Technology R&D Division of KARI(Korea Aerospace Research Institute) will be launched in late 2002. It is a three-stage, liquid propellant rocket which can reach 250 km altitude and will carry out observation of ozone layer and scientific experiments, such as microgravity experiment, and atmospheric measurement. KSR-III is believed to be an intermediate to the launch vehicle capable of carrying a satellite to its orbit. Space Test Department of KARI performed GVT(Ground Vibration Test) fer KSR-III EM at Rocket Test Building of KARI. GVT is very important for predicting the behavior of rocket in its operation, developing flight control program and performing aerodynamic analysis. This paper gives an introduction of rocket GVT configuration and information on test procedures, techniques and results of It. In this test. to simulate free-free condition, test object hung in the air laterally by 4 bungee cords specially devised. For the excitation of test object, pure random signal by two electromagnetic shakers was used and total 22 frequency response functions were achieved. Polyreference parameter estimation was performed to identify the modal parameters with MIMO(Multi-Input-Multi-Output) method. As the result of the test, low frequency mode shapes and modal parameters below 60Hz were identified

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.280-293
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• 2004

Statement of problem. Glass fiber post is one of recent developments to accommodate esthetic restoration for endodontically treated teeth. This has many advantages over conventional post system in physical properties, esthetic factor, risk of root and restoration fracture, adhesion to core, radiopacity, removal and retrievabilty, biocompatibility and chemical stability. Purpose. This in vitro study was to evaluate the most suitable type of resin core for the glass fiber post through surveying the fracture modes and the maximum load that fractures the tooth. Material and methods. 50 sound maxillary premolars restored with glass fiber posts($ParaPost^{(R)}$ Fiber White) and different types of resin cores(ParaCore, $Z100^{TM}$, $Rebilda^{(R)}$ and $Admira^{(R)}$) were prepared and loaded to faiure in a universal test machine. The maximum fracture load and fracture mode were investigated in the specimens that were restored with resin and those of metal cast and core. With the data, Wilcoxon rank sum test was used to validate the significance between the test groups, and Tukey' s studentized range test was used to check if there is any significant statistical difference between each test group. Every analysis was approved with 95% reliance. Results. On measuring the maximum fracture load of teeth specimens, there was a significant difference between the maximum fracture loads of the tooth specimens. ParaCore showed the highest mean maximum fracture load followed by $Z100^{TM}$. And, the distribution of fracture mode of tooth specimens showed generally Type D, the three parted fracture of the core around the post was mostly seen(62.5%), and specifically, ParaCore showed 90% and $Z100^{TM}$ showed 100% Type D fracture. Conclusion. Referring to the values of maximum fracture load and mean compressive fracture load, ParaCore and $Z100^{TM}$ had high values and are recommended as tooth colored resin core material for glass fiber post. CLINICAL IMPLICATIONS. This study was carried out intending to be of aid in selecting the appropriate resin core for the glass fiber post. The dual cure type composite resin ParaCore and light cure type composite resin $Z100^{TM}$ have good properties and are recommended as tooth colored resin core material for glass fiber post.

• Journal of Global Scholars of Marketing Science
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• v.19 no.2
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• pp.53-67
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• 2009

For the last decades, service quality has been studied as one of the most important tools for a service company to compete with the other companies. Based on these past researches, it has been agreed that the service quality is a basic and powerful tool to create the competitive advantage. Due to similar reason, many service marketing practitioners have been also focused on the service quality to retain the existing consumers and collect the new consumers. However, service quality is subjectively perceived by individual consumers. Consumer evaluation of service quality can be different from each other. Especially consumers with one life-style may evaluate the service quality differently from the consumers with the other life-styles. Therefore we need to know whether there are differences in service quality perception on the categories of life-style. Life-style refers to a distinctive mode of living in its aggregate and broadest sense. It embodies the patterns that were developed and emerged from the dynamics of living in a society. Since the concept of life-style and its relationship to marketing was introduced in 1963 by William Lazer, methods of measuring the life-style and their application have been developed. Life-style has been usually used to segment the marketplace because it offers marketers a unique and important view of the market. When Life-style is combined with clustering methods, life-style segmentation can generate identifiable whole persons rather than isolated fragment. Life-style segmentation begins with people instead of products and classifies them into different life-style types, each characterized by a unique style of living based on a wide range of activities, interests, and opinions(Plummer, 1974). In this study we applies the life-style segmentation based on the AIO(Activities, Interests, and Opinions) to the consumers of the large discount stores. In Korea, the large discount store market has entered into maturity stage so that the market differentiation strategy is becoming a more critical issue to the marketing practitioners. One of the most important tools to differentiate from the competitors in large discount store market is continuously to provide service of better quality than competitors. This study tries to find answers about the following questions: 1) How can we categorize the consumer life-styles in the large discount store? 2) What are the characteristics of the categorized groups? 3) Are there any differences in service quality perception among the consumers with different life-styles 4) Are there any differences in consumer behavior among them in the large discount store? For the purpose, we collected survey data from consumers and analyzed the data with the SPSS package where we had $X^2$-test, factor analysis, ANOVA, MANOVA, and cluster analysis. The survey was made during one month in the April of 2008. Among the collected 306 copies of questionnaires, 281 copies were chosen as the effective samples for empirical analysis except 25 copies with wrong responses. To identify the life-style patterns, we used the measures employed by Kim and Kwon(1999), where 44 items on a seven-point scale were used to measure factors of the life-style patterns. The Principal Component Method was used for factor extraction, and the VARIMAX orthogonal factor rotation was employed. The 7 items showing low factor loading were eliminated. The results of the factor analysis suggested that nine factors of the life-style patterns were identified as follows: 1) the equality-of-sexes and pursuit-of-independence tendency 2) self-management tendency 3) sociable tendency 4) self-display tendency 5) degree of a dilettante life 6) pursuit-of-information tendency 7) bargain hunter tendency 8) TV preference tendency 9) pursuit-of-leisure tendency. Next, after the K-means cluster analysis was performed with nine factors of the life-style patterns, the life-styles of the respondents were classified into four groups which are named as the 'progressive practicality-oriented group', 'positive success-oriented group', 'sociable ostentation-oriented group', 'stable conservation-oriented group'. The analysis results for usage behavior between the market segments showed statistically significant differences in the frequency of usage, duration time in the store, consumer satisfaction, and loyalty. Also, we tried to investigate whether the large discount store consumers differently perceive the quality of service based upon the types of life-style. To measure the service quality of large discount store, we adapted several measurement models measuring the service quality such as SERVPERF, BCP, R-SERVPERF, R-BCP. MANOVA and One-Way ANOVA were performed to confirm the difference in service quality perception based on the market segments. The results have also shown significant differences between life-style types in service quality perception. These findings show that the large discount store marketers should consider consumer life-style as one of the most important market segments for marketing and understand the difference in service quality perception between life-style types. Our findings give important implications to marketers of large discount stores as well as life-style researchers. First, this study showed there were significant differences in consumer's service quality perception and usage behavior between the types of life-style. It provides evidence that the life-style approach can be a important basis in segmenting the large discount store market and will make consumers perceive the service quality high. Second, most previous researches on service quality have been in aggregate level. However, our results imply that the future research on service quality have to focus on segment level.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.140-145
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• 2007

Acrylamide has been found in many foods. Acrylamide in foodstuffs were analyzed by a GC/MS after bromination of acrylamide or by a LC/MS for underivatized acylamide. Time consuming and laborious clean up procedures is applied for the purification of the extract, in these methods. In this study, a simple and fast method without clean up step for the analysis of acrylamide in mainstream cigarette smoke was developed by using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and the effects of tobacco leaf constituents on acrylamide content was observed. The analysis of acrylamide in mainstream cigarette smoke started to collect TPM (total particulate matter) from smoking and to extract by 0.1 % acetic acid solution and then to detect by liquid chromatography tandem mass spectrometry using electrospray in the positive mode. The recovery of acrylamide in 2R4F reference cigarette was 98 % and the reproducibility was 2.5 % and the limit of detection was 1.6 ng/mL. Reducing sugars and amino acids are considered to be main precursors of acrylamide in foodstuffs. Cut tobacco contain substantial amounts of reducing sugars and amino acid which may be explained the occurrence of acrylamide in mainstream cigarette smoke. The effects of reducing sugars and total nitrogen studied in an experiment with a various tobacco types. This result indicated that reducing sugars are not limiting factor for acrylamide formation, but the level of acrylamide in cigarette smoke was significantly correlated with the total nitrogen contents.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.251-260
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• 1998

It is well known that the clinical test for responsibility of accurate fertilization capacity in male partners is very important to diagnose and treat the infertility. However, it has been reported that the traditional semen analysis cannot accurately predict fertilization and pregnancy potential. The present study was performed to evaluate the acrosomal reaction to ionophore challenge (ARIC) test as a prognostic indicator for fertilization of sperm and oocyte in an in vitro fertilization and embryo transfer (IVF-ET) program. From March 1996 to Februry 1997, 30 couples undergoing IVF program were allocated to this study group. All female partners in the study group were 35 years old or less and their serum level of basal follicle stimulating hormone (FSH) and estradiol $(E_2)$ were normal. All the male partners have normal parameters of semen analysis. The ARIC tests were performed on the day of ovum pick up and in vitro insemination in all the male partners. The controlled ovarian hyperstimulation (COH) using luteal long protocol of gonadotropin releasing hormone (GnRH) agonist was used in all couples for IVF-ET. The acrosomal reaction with $10{\mu}l$ of 10% DMSO was induced spontaneously in $10.1{\pm}9.8%$, and acrosomal reaction with calcium ionophore A 23187 was induced in $27.4{\pm}18.1%$, and the ARIC value was $17.4{\pm}16.2%$. There were no significant correlation between the ARIC value and the fertilization rate ($r^2$=0.044, p=0.268). There were also no significant correlation between the ARIC value and the percentage of the grade I, II embryos ($r^2$=0.046, p=0.261). On the basis of above results, it was suggested that ARIC test might not be a useful prognostic indicator for fertilization in IVF-ET in male partners with normal parameters of conventional semen analysis. We guessed that IVF-ET could be performed to the patients primarily without universal appilcation of ARIC test to all male partenrs, and if fertilization failure occurs, the micro assisted fertilization (MAF) such as intracytoplsmic sperm injection (ICSI) might be used as an alternative mode of treatment with acceptable success rate.

• Anxiety and mood
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• v.18 no.2
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• pp.72-79
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• 2022

Objective : Any traumatic event can be a risk factor, for subsequent mental disorder. However, childhood trauma, especially in interpersonal nature, is associated with later development of complex symptom patterns. This study examined the role of dissociation as a mediator between childhood trauma and symptom complexity. Methods : A pooled data of 369 psychiatric outpatients at a university-affiliated hospital was analyzed for descriptive statistics, group differences, and bivariate correlation analysis to verify a structural model. The questionnaires included the Symptom Checklist-90-Revised, the Trauma History Screen, the Dissociative Experiences Scale-Taxon, the Beck Depression Inventory, the Beck Anxiety Inventory, and the Abbreviated PTSD checklist. Results : When other trauma variables were controlled, childhood interpersonal trauma had significant correlation with symptom complexity (r=0.155, p=0.003). Among the paths analyzed, that of childhood interpersonal trauma and dissociation showed the greatest impact on symptom complexity (b=9.34, t=5.75, p<0.001). Based on the significance of the indirect impact, the results suggest a complete mediation impact of dissociation on symptom complexity. Conclusion : This study validated that childhood interpersonal trauma impacts symptom complexity, through the sequential mediating impact of dissociation. Thus, clinicians should understand childhood interpersonal trauma, dissociation, and symptom patterns in a complex and interacting mode, and develop effective pertinent treatment strategies.