• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.475-485
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• 2008

This paper intends to enhance the reliability and performance of domestic elastomeric bearings through the proposal of directions for the improvement of their stiffness regard to the Korean industrial standard KS F 4420 relative to the evaluation of design/fabrication/quality. Therefore, comparative analysis of the compressive elastic modulus, stiffness measurement method and performance evaluation method of KS F 4420 with those of Eurocode, Japanese bearing manual, and ISO code was performed, and measurement tests on the compressive stiffness and shear stiffness of common elastomeric bearings produced in Korea were conducted. The experimental results reveal that differences of about 20% and 13% occurred respectively for the compressive stiffness and shear stiffness according to the definition adopted for the stiffness. The measured values for the stiffness of the domestic elastomeric bearings were also verified to exhibit large deviation from the formula proposed by KS F 4420. Elastomeric bearings that does not have appropriate compressive stiffness required at the design can result in uneven deflection at supports of bridges and excessive stress in girders. Accordingly, the establishment of compressive elastic modulus formula and performance evaluation criteria fitted to the domestic circumstances through the execution of performance evaluation of bearings presenting diversified shapes and shape factors appears to be necessary for the domestic bearings to meet the performance required in design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.617-625
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• 2008

In low-density areas where travel pattern is widely dispersed and travel demand is relatively low, transit operators find it very difficult to provide a reasonable level of service at a reasonable cost. Timed-transfer system or network, if designed properly, can provide a reasonable level of service for passengers using transit systems serving low-density areas. The paper intends to apply a timed-transfer system for bus lines serving Yangsan City area and to assess the effects resulted from the application. The concept of a timed-transfer network/system is briefly described, and the present conditions of bus systems in Yangsan City area are discussed, focusing on the aspects of network type and the related problems. The bus timed-transfer network for the area is then developed by adjusting the existing routes and network with the consideration of travel time, route alignments, headways and transfer centers. One must note that developing a timed-transfer network presumes that network and schedule should be developed together. The effects of the developed time-transfer system on the passengers and operators are found substantially so as to justify its introduction to the City. The results of this study will be of considerable use for planners to design the transit systems in low density areas, where in general travel activities are widely dispersed and travel demands are low, so that provision of good quality of transit services are difficult.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.753-759
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• 2006

To predict service life of concrete structures exposed to chloride attack, surface chloride concentration, diffusion coefficient of chloride ion, and chloride corrosion threshold value in concrete, are used as important factors. Of these, as the diffusion coefficient of chloride ion for concrete is strongly influenced by concrete quality and environmental conditions of structures and may significantly change the service life of structures, it is considered as the most important factor for service life prediction. The qualitative factors affecting the penetration and diffusion of chloride ion into concrete are water-cement (W/C) ratio, age, curing conditions, chloride ion concentration of given environment, wet and dry conditions, etc. In this paper the influence of W/C ratio and curing conditions on the diffusion characteristics of chloride ion in concrete was investigated through the chloride ion diffusion test. In the test, the voltages passing through the diffusion cell were measured by accelerated test method using potential difference, and then with the consideration of IR drop ratio the diffusion coefficient of chloride ion for concrete with different W/C ratios were estimated by Andrade's model. Furthermore, under different curing conditions formulas for the estimation of the diffusion coefficient of chloride ion have been proposed by the regression analysis considering the effect of W/C ratio and age.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.573-580
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• 2010

This paper presents the development of self-consolidating concrete (SCC) using lightweight aggregates. SCC using Lightweight aggregate properties have been evaluated in terms of flowability, segregation resistance and filling capacity of fresh concrete as per the standards of the Japanese Society of Civil Engineering (JSCE). The measurement of the mechanical properties of hardened SCC using lightweight aggregate, including compressive strength, splitting tensile strength, elastic moduli and density, as well as its dry shrinkage and carbonation properties were also carried out. The characteristics of SCC using lightweight aggregate at the fresh state showed that as the use of the lightweight aggregate, the flowability improves without exception of Mix No. 9 but the segregation resistance tends to decrease without exception of Mix No. 3, 4 and 5. The 28 days compressive strength of the SCC using lightweight aggregate was found to be 30 MPa or higher. The relationship between the compressive strength and the splitting tensile strength was found to be similar to the expression presented by CEB-FIP, and the relationship between the compressive strength and the elastic moduli was found to be similar to the expression suggested by ACI 318-08 which takes into consideration the density of concrete. The density of the SCC using lightweight aggregate decreased by up to 26% compared to that of the control SCC. Also, The dry shrinkage and carbonation depth of the SCC using lightweight aggregate increased compared to that of the control SCC.

• Korean Journal of Psychosomatic Medicine
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• v.31 no.1
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• pp.1-9
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• 2023

Patients with neurocognitive disorder show behavioral psychological symptoms such as agitation, aggression, depression, and wandering, as well as cognitive decline, which puts a considerable burden on patients and their families. For the treatment of behavioral psychological symptoms, patient-centered, non-pharmacological treatment should be used as a first line approach. This paper describes non-pharmacological interventions to manage and treat behavioral psychological symptoms in patients with neurocognitive disorder. In order to control behavioral psychological symptoms such as agitation, depression, apathy, insomnia, and wandering, it is important to identify and evaluate factors such as environmental changes and drugs, and then solve such problems. Non-pharmacological interventions include reassurance, encourage, distraction, and environmental change. It is necessary to understand behavior from a patient's point of view and to approach the patient's needs and abilities appropriately. Reminiscence therapy, music therapy, aroma therapy, multisensory stimulation therapy, exercise therapy, light therapy, massage therapy, cognitive intervention therapy, and pet therapy are used as non-pharmacological interventions, and these approaches are known to improve symptoms such as depression, apathy, agitation, aggression, anxiety, wandering, and insomnia. However, the quality of the evidence base for non-pharmacological approaches is generally lower than for pharmacological treatments. Therefore, more extensive and accurate effectiveness verification studies are needed in the future.

• 한국노년학
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• v.30 no.3
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• pp.709-726
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• 2010

As S. Korea is aging faster than any other industrialized countries, there exists a need to understand how best to improve the quality of life of the elders. The main purpose of this study is to examine the predictors of life satisfaction in the nationally representative sample of adults aged 65 and older (n=4,155) drawn from the Wave I (2006) of the Korean Longitudinal Study on Aging. Hierarchical multiple regression analysis was run to assess the unique explanatory contribution of socio-demographics, social network, activity participation, and physical/psychological health on the life satisfaction. Three separate analyses were undertaken to note differences by education level: older adults with no formal education, those who had completed 9th grade, and those who had completed 12th grade and more. There are three main findings: 1) Physical/psychological health variables such as subjective health, regular exercise, and depression were significant predictors of life satisfaction regardless of education level; 2) While social network and activity participation factors influence life satisfaction of the two lower education groups, such factors don't affect the highest education group; 3) Marital status, household income, and location of residence were significant demographic predictors of life satisfaction regardless of education level. Implications for program development and policy are discussed in this paper.

• Issues in Feminism
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• v.10 no.1
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• pp.123-158
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• 2010

For the last several months, abortion debates have sparkled in Korea. The government has escalated the need of active punishment of illegal abortions to solve low fertility problems, while some obstetricians and gynecologist have proclaimed stoppage of illegal abortions suing colleague doctors who has conducted illegal abortions. Women's rights groups and researchers have also responded to the abortion debate claiming that women's decisions over their pregnancy are important in making of abortion policies. To contribute to Korean abortion debates, his paper aims to analyze European experiences of abortion polices in relation to the consequences on women's health. For the analysis of European abortion experiences, three countries - Ireland, U.K, and Netherland -are chosen. These three countries are selected since their legal and social acceptance of abortion and the level of safe abortion system are different. Each country is reviewed by national abortion policy, legal regulation, medical system and the role of civil society. The analysis shows several implications for abortion debates occurring in Korea. Various systematic policy mechanisms - abortion on women' request, abortions without complicated doctor's referrals, transparent and anonymous counseling and information provision regarding abortion, training and education for medical professionals to guarantee high quality abortion, abortions funded publicly for women to improve their access to abortions, steady monitoring and auditing abortion procedures and outcomes for safe abortion and so on - are required in Korean society. Two track procedures - safe abortion on women's request and prevention of unwanted pregnancy - are needed for reproduction of healthy women and society.

• Asia Marketing Journal
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• v.9 no.2
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• pp.97-129
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• 2007

The critical link between consumer-based internet ordering and the delivery of the product to the consumer is a key success factor in online shopping. Market areas of online shopping company implies the range of space where products ordered from online shopping can be physically delivered to customers distributed over space with reasonable shipping cost and lead time through the physical distribution network. The average rate of growth in online shopping is 36% per year in Korea for the last 5 years. But there are no maps available that describe sales/delivery density of online shopping, few researches are focused on the short-term/long-term adaptation to demand increase by online shopping. In this paper (1) Maps of trade area are described indicating the sales/delivery density around the nation. (2) Empirical researches suggested that short-term adaptation to demand increase resulted in price reduction and service in enhancement of service quality in local transportation. But the long-term adaptation on the parts of parcel delivery industry are to be investigated in future researches.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.56-63
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• 2023

In this paper, we studied the effect of electron beam irradiation on sol-gel indium-gallium-zinc oxide (IGZO) thin films under air and nitrogen atmosphere and carried out the electrical characterization of the s ol-gel IGZO thin film transistors (TFTs). To investigate the optical properties, crystalline structure and chemical state of the sol-gel IGZO thin films after electron beam irradiation, UV-Visible spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were carried out. The sol-gel IGZO thin films exhibited over 80% transmittance in the visible range. The XRD analysis confirmed the amorphous nature of the sol-gel IGZO films regardless of electron beam irradiation. When electron beam irradiation was conducted in a nitrogen (N₂) atmosphere, we observed an increased proportion of peaks related to M-O bonding contributed to the improved quality of the thin films. Sol-gel IGZO TFTs subjected to electron beam exposure in a nitrogen atmosphere exhibited enhanced electrical characteristics in terms of on/off ratio and electron mobility. In addition, the electrical parameters of the transistor (on/off ratio, threshold voltage, electron mobility, subthreshold swing) remained relatively stable over time, indicating that the electron beam exposure process in a nitrogen atmosphere could enhance the reliability of IGZO-based thin-film transistors in the fabrication of sol-gel processed TFTs.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.29-42
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• 2023

In this paper, we propose a method to enhance the prediction accuracy of solar irradiance for three major South Korean cities: Seoul, Busan, and Incheon. Our method entails the development of five generative models-vanilla GAN, CTGAN, Copula GAN, WGANGP, and TVAE-to generate independent variables that mimic the patterns of existing training data. To mitigate the bias in model training, we derive values for the dependent variables using random forests and deep neural networks, enriching the training datasets. These datasets are integrated with existing data to form comprehensive solar irradiance prediction models. The experimentation revealed that the augmented datasets led to significantly improved model performance compared to those trained solely on the original data. Specifically, CTGAN showed outstanding results due to its sophisticated mechanism for handling the intricacies of multivariate data relationships, ensuring that the generated data are diverse and closely aligned with the real-world variability of solar irradiance. The proposed method is expected to address the issue of data scarcity by augmenting the training data with high-quality synthetic data, thereby contributing to the operation of solar power systems for sustainable development.