• Journal of the Korean Geotechnical Society
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• v.39 no.7
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• pp.5-15
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• 2023

The evaluation of passive earth pressure plays a crucial role in the design of earth-retaining structures such as retaining walls and temporary earth-retaining walls to withstand horizontal earth pressure. In the earth pressure theory, active and passive earth pressures represent the earth pressures at the limit state, where the wall displacement reaches the maximum allowed displacement. In the design of earth-retaining structures, the passive earth pressure is considered as the resisting force. In this context, the limit displacement at which passive earth pressure occurs is significantly greater than that associated with the active earth pressure. Therefore, it is irrational to apply this displacement directly to the calculation of passive earth pressure. Instead, it is necessary to consider the mobilized passive earth pressure exerted at the allowable horizontal displacement to evaluate the structural stability. This study proposes an allowable wall displacement, denoted as 0.002 H (where H represents the excavation depth), based on a literature review that focuses on sandy soils. To calculate the mobilized passive earth pressure from the wall displacement, a semi-empirical equation is proposed. By analyzing the obtained data on mobilized passive earth pressure, a reduction factor applicable to Rankine's passive earth pressure is proposed for practical application in sandy soils under different wall movement types.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.166-178
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• 2023

This study aims to introduce and assess CNN Deep Learning methods to analyze visual landscape images on social media with embedded user perceptions and experiences. This study analyzed visual landscape images by focusing on a healing place. For the study, seven adjectives related to healing were selected through text mining and consideration of previous studies. Subsequently, 50 evaluators were recruited to build a Deep Learning image. Evaluators were asked to collect three images most suitable for 'healing', 'healing landscape', and 'healing place' on portal sites. The collected images were refined and a data augmentation process was applied to build a CNN model. After that, 15,097 images of 'healing' and 'healing landscape' on portal sites were collected and classified to analyze the visual landscape of a healing place. As a result of the study, 'quiet' was the highest in the category except 'other' and 'indoor' with 2,093 (22%), followed by 'open', 'joyful', 'comfortable', 'clean', 'natural', and 'beautiful'. It was found through research that CNN Deep Learning is an analysis method that can derive results from visual landscape image analysis. It also suggested that it is one way to supplement the existing visual landscape analysis method, and suggests in-depth and diverse visual landscape analysis in the future by establishing a landscape image learning dataset.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1C
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• pp.11-20
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• 2009

A new alternative method based on HWAW method to detect underground anomaly was introduced. The location of underground anomaly can be estimated by using 2-dimensional image of phase velocity image with position and wavelength based on distortion phenomena of surface wave due to underground anomaly. Overall procedure of proposed method such as field testing, signal processing and interpretation of the result was introduced. Numerical verification study was performed by using various ground models containing underground anomaly. According to the condition of anomaly, the propagation and reflection characteristics of surface wave were different and this could be more easily shown in the image of phase velocity. Some rules of distortion phenomena were found and these become clues for estimating underground anomaly in interpreting real field data. Field verification tests were performed with conventional geophysical methods such as DC resistivity method and GPR. Though field condition is not homogeneous like numerical models, similar distortion phenomena were found in the testing results and estimated location of underground anomaly was agreed well with the results of another geophysical methods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.335-344
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• 2006

In this study, sequential mixing model (SMM) was proposed based on the Taylor's theory which can be summarized as the fact that longitudinal advection and transverse diffusion occur independently and then the balance between the longitudinal shear and transverse mixing maintains. The numerical simulation of the model were performed for cases of different mixing time and transverse velocity distribution, and the results were compared with the solutions of 1-D longitudinal dispersion model (1-D LDM) and 2-D advection-dispersion model (2-D ADM). As a result it was confirmed that SMM embodies the Taylor's theory well. By the comparison between SMM and 2-D ADM, the relationship between the mixing time and the transverse diffusion coefficient was evaluated, and thus SMM can integrate 2-D ADM model as well as 1-D LDM model and be an explanatory model which can represents the shear flow dispersion in a visible way. In this study, the predicting equation of the longitudinal dispersion coefficient was developed by fitting the simulation results of SMM to the solution of 1-D LDM. The verification of the proposed equation was performed by the application to the 38 sets of field data. The proposed equation can predict the longitudinal dispersion coefficient within reliable accuracy, especially for the river with small width-to-depth ratio.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.543-560
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• 2010

Safety-related concrete structures in a nuclear power plant must be protected against the impact of flying objects, referred to in the profession as missiles. In practice, the structural verification is usually carried out by means of empirical formulas, which relate the velocity of the impinging missile to the wall thickness needed to prevent scabbing or perforation. The purpose of this study is to reevaluate the predictability of the local effect prediction formulas for the penetration and scabbing depths and perforation thickness. Therefore, available formulas for predicting the penetration depth, scabbing thickness, and perforation thickness of concrete structures impacted by solid missiles are summarized, reviewed, and compared. A series of impact analyses is performed to predict the local effects of the projectile at impact velocities varing from 95 to 215 m/s. The results obtained from the numerical simulations have been compared with tests that were carried out at Kojima to validate numerical modelling. The simulation results show reasonable agreement with the Kojima test results for the overall impact response of the RC slabs. From these results, it seems that the Degen equation give a very good estimate of perforation thickness against a tornado projectile for test data. Finally, the results obtained from the impact analysis have been compared with Degen formula to determine the perforation thickness of the RC slab.

• 한국노년학
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• v.29 no.2
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• pp.477-488
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• 2009

Purpose: This study was conducted to investigate newly admitted nursing home resident's experience and adjustment problems in the early stage of institutionalization. Method: In depth interviews was done on 6 elderly residents who were newly admitted. Data from the interview were analyzed using theme analysis method. Results: Results showed that reasons for Institution admission were decreasing physical health and cognitive functioning. Residents reported that difficulties they experienced in institution life were lack of individualized care, loss of autonomy and privacy associated with the demands of group living, and loss of control over activities of daily living. Conclusion: Efforts need to be made to maintain the residents' decision-making and autonomy. Listening intentionally, offering choices, and promoting personal identity might be utilized to reduce relocation stress and enhance adaptation to nursing home living.

• 한국노년학
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• v.30 no.3
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• pp.779-791
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• 2010

This study was to examine the differential impacts of social experiences and conditions on health among men and women aged 65 years or older, using data of the "2004 Survey on living Status of the Korean Elderly". The outcome variables were any disability, self-rated health, multiple morbidity, and self-rated quality of life. Multiple Classification Analysis was used to test the differential exposure to social factors contributes to gender difference in health. Gender differences in vulnerability of each individual socioeconomic, psycho-social, and behavioral factors for health were assessed by comparing logit coefficients in men and women. I found that gender difference in exposure to social factors contribute to inequalities in health between older men and women, however, gender inequalities remained after controlling for differential exposure except in case of quality of life. In addition, gender differences in health were further explained by differential vulnerabilities to social factors between men and women. Findings of this study may affirm the importance of further and deeper investigation of gender differences in health in later life. Gender sensitive approach in health planning and polices for the elderly is also suggested.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.377-391
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• 2022

The objective of this study is to understand the operational status of the support projects for childcare in daycare centers operated by the Support Centers for Childcare(SCC) during the COVID-19 pandemic and find ways to improve and develop the project operation. To this end, data were collected and analyzed through in-depth interviews from the 1st week to the 4th week of February 2022 with six childcare agents in charge of the support projects for childcare in daycare centers in the SCC located in Seoul and Gyeonggi Province. As a result of the study, it was found that the demand for diversification of project operation methods, expansion of non-face-to-face education, individual consulting, and small-scale education increased while operating the support projects for childcare in daycare centers in the SCC during the COVID-19 pandemic. Operational difficulties were found to be a lack of ability to use media, the burden of coping with unpredictable situations, and insufficient communication between daycare centers and childcare policy institutions. As for the support needs, it was found that it is necessary to employ computer specialists, establish an environment for activating online education, and provide an efficient work delivery system in emergencies.

• 한국노년학
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• v.39 no.3
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• pp.485-515
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• 2019

The purpose of this study was to explore bullying among senior women at a senior center. Using ethnographic research technique, we examined the process in which members of the senior center engaged in and responded to bullying. Purposive sampling method was used to choose a senior center as the subject of this study. Within the center, 16 senior women participated in the study. In-depth interviews and participatory research methods were used to collect data. We analyzed the transcripts of the interviews based on the ethnographic analysis method presented by Spradley (1979). Themes that emerged from these participatory research and interviews include: members of the senior center creating loners, people being bullied causing damages to the group, taking actions to respond to bullying, and failing to solve the bullying problems. First, the victims of bullying became loners with no one to rely on through other members' verbal attacks, discrimination, isolation, and stopping the victim to use the senior center. Second, the victims were under attack but also caused troubles at the senior center and harmed others at the same time. Third, while engaging in bullying, senior women attempted to deal with bullying problems in many ways. These attempts include: avoiding the conflict, withstanding, attempting to mediating, and so on. Finally, bullying remained to be a recurring phenomenon at the senior center. New victims of bullying continuously appeared and the influence of bullying was felt not only within the senior center but outside as well. Based on the findings of this study, we suggest that practitioners and researchers take into account factors that affect bullying among senior women.

• Korean Journal of Social Welfare Studies
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• v.41 no.1
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• pp.307-343
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• 2010

This study, based on grounded theory, explores the child-rearing process of defecting North Korea women in South Korea. Interviews were conducted with five defecting North Korea women who had children. With the permission of the participants, the interviews were recorded with the digital recorder and transcribed by the researchers. Data were collected with in-depth interviews and observations until they were saturated. The interviews were analysed according to the constant comparative method used in grounded theory. The study derived 86 concepts, 31 subcategories and 11 categories in open coding. A core category was 'enduring hardships with hopes for children's success ' in selective coding. And The child-rearing process of the defecting North Korea women takes 'stage of entry', 'stage of confrontation', 'stage of struggle', 'stage of adjustment' and 'stage of hope for children's success'. The findings of the study will be useful in seeking an effective social welfare intervention plan for successful child-rearing of defecting North Korea women in South Korea.