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An Experimental Study on Relationship Between Half-Cell Potential and Corrosion Current Density of Chloride-Induced Corroded Steel in Concrete (염해에 따라 콘크리트 속에서 부식된 철근의 반전지전위와 부식전류밀도의 상관관계에 관한 실험적 연구)

  • Jo, Sang-Hyeon;Kim, Dong-Won;Kee, Seong-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.1-13
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    • 2022
  • This study aims to investigate the feasibility of the half-cell potential (HCP) measurements on the concrete surface for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete. A series of experimental study is performed to measure HCP (or corrosion potential, Ecorr) and corrosion current density (icorr) of reinforcing steel in concrete cube specimens, with a side length of 200 mm. Various corrosion levels in a range of 0% to 20% of the test specimens are accelerated by impressing current to the reinforcing steel in concrete immersed in 3.0 % NaCl solution. HCP is measured in accordance with ASTM C876-15, and corrosion current density is determined by using the Stern-Geary equation and measured polarization resistance measured by electrochemical impedance spectroscopy (EIS). As a result, a numerical formula that relates HCP and icorr in the test specimen is established by a regression analysis of the measured data in this study. It is observed that HCP is linearly correlated with log(icorr) with a R2 greater than 0.87, which is less affected by the experimental variables such as concrete mixture proportion, diameter of reinforcing steel and the amount of applied current in this study. These results exhibit that HCP measurements could be effective for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete in the case of exposed to a certain consistent environment.

The Double Mediating Effects of Ego-Resilience and Impulsivity between Smartphone Addiction and Depression among Office Workers (직장인의 스마트폰 중독과 우울감 사이에서 자아탄력성과 충동성의 이중 매개효과)

  • Kwon, Se-yong;Kim, Hyeong-ho
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.355-363
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    • 2022
  • Purpose : The purpose of this study was to investigate the double mediating effect of ego-resilience and impulsivity in the effects of smartphone addiction on depression among office workers. Research design, data and methodology : The subjects of this study were office workers working in four cities: Seoul, Daejeon, Chungnam, and Chungbuk Province, and the total number of respondents was 286. Descriptive statistics, difference test (t-test, ANOVA), correlation analysis, and double-mediated effect analysis were used for statistics. Results : The results of this study are as follows. First, as a result of the difference analysis, there was no difference in depression according to the general characteristics of the subjects of this study, such as gender, age, marital status, and salary. Second, as a result of correlation analysis, smartphone addiction showed a negative correlation with ego-resilience, and a positive correlation with impulsivity and depression. Also, ego-resilience showed negative correlation with impulsivity and depression. Impulsivity showed a positive correlation with depression. Third, as a result of dual mediating effect analysis, it was found that ego-resilience and impulsivity played double-mediated role between smartphone addiction and depression. Conclusions : Based on the results of this study, theoretical measures centered on ego-resilience were discussed and presented in order to positively induce the decrease in impulsivity and depression due to smartphone addiction among office workers.

A study on calculation of permeable area ratio in impervious basin using K-LIDM model (K-LIDM 모형을 이용한 불투수유역 내 투수면적비 산정에 관한 연구)

  • Park, Jaerock;Kim, Jaemoon;Baek, Jongseok;Seo, Youngjae;Shin, Hyunsuk
    • Journal of Korea Water Resources Association
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    • v.55 no.11
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    • pp.969-977
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    • 2022
  • In order to respond to the increase in water disasters due to climate change and urbanization, research on low impact development (LID) techniques and application to cities are expanding. The LID technique is a technology that reduces rainwater runoff in the city, controls various water disasters such as flash floods, etc. in an eco-friendly way, and restores the urban water circulation system to a natural water circulation system. However, quantitative analysis of stormwater runoff reduction through the LID technique is insufficient. Therefore, this study analyzed the ratio of the permeable area required to reduce the surface runoff of rainfall (25 mm/hr, 50 mm/hr, 100 mm/hr) with respect to the impervious watershed area of the old city using the permeable pavement. As a result of the analysis, it was found that a permeable area ratio of 7.14 to 12.63% of the total area was required for 25 mm/hr, 15.79 to 26.97% for 50 mm/hr, and 30 to 55.81% for 100 mm/hr.

A Study on Residents' Perception and Evaluation of Urban Greenway -Centered on the Greenway of Zhengzhou Dongfeng Canal- (도시 그린웨에이 대한 감지(感知)와 평가 연구 -정주시(郑州市) 동풍거(东风渠) 그린웨이를 중심으로-)

  • Zhang, Lin;Moon, Jeong-Min
    • Journal of Digital Convergence
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    • v.20 no.5
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    • pp.919-929
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    • 2022
  • As a new type of healthy public space, greenway users carry out leisure activities, exercise, sightseeing and necessary transportation in greenway. However, at present, there is little research on greenway users' evaluation and perception of greenway, and there is no comprehensive exploration of Greenway environment from a humanistic perspective. Combined with the research and actual situation of the existing representative greenways in Chinese cities, this paper refers to a large number of documents, applies the semantic difference method and multiple regression analysis method, analyzes the current situation of the Dongfengqu greenway, explores the influencing factors and impact evaluation of the greenway environment from the perspective of greenway users' perception, and puts forward suggestions on the optimization of the greenway environment in Zhengzhou from multiple levels. The main conclusion of this paper comes from the data conclusion obtained by semantic difference method, which is feasible in the resident evaluation of greenway use. The feedback results of post use evaluation can provide a reliable reference for the planning and design of similar greenways in the future.

Assessment of Adequacy of Urban Water Supply (도시 상수도 공급량 산정의 적정성 평가)

  • Kim, Jang Jin;Chang, Hyung Joon;Lee, Ho Jin
    • Journal of Korean Society of Disaster and Security
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    • v.14 no.4
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    • pp.61-67
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    • 2021
  • In this study, the adequacy of water supply critical factors of urban design was examined. The supply of water supply is analyzed in various ways as the design progresses. Starting with basic data collection and analysis a supply and demand plan is established to calculate the amount of water supply and in this study the adequacy of population estimation and original unit calculation was evaluated. Among the second new cities where actual data can be secured Wirye New Town was selected as the study target area. Related data were analyzed to confirm the future population and the original unit and compared with the measured data. As of September 2020, the population of Wirye New Town was 93,977, showing the appropriateness of about 84% with a planned population of 110,990 confirming that the planned population and the actual population were almost similar. In the case of the original unit, it was calculated as 314 liters per person in Seoul and 320 liters per person in Seongnam at the time of design. As a result, it was found that there was some agreement in the population estimation while examining the supply in the planned city. In the case of Korea, there is a lot of interest in revitalizing the existing city, away from continuous development. Therefore it is judged that there is a need for further research on the adequacy of supply for the old city center.

A Study of Walking Activity Time Characteristics Based on the Time Use Survey (생활시간조사에 기반한 보행활동시간 특성 분석)

  • Park, Jihun;Ku, Donggyun;Jeong, Ilho;Lee, Seungjae
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.21 no.3
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    • pp.53-61
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    • 2022
  • Despite the increasing importance of pedestrians and their walking individualities, walking activity time characteristics are yet to be studied. This study analyzes the walking activity time characteristics by group using the Time Use Survey data. In order to analyze the characteristics of each pedestrian group, cluster analysis and correspondence analysis were performed by dividing the walking styles into utilitarian and leisure-purpose walking. Those who did not undertake utilitarian walking were mainly the worker group, whereas subjects who walked could be classified into homemaker and student groups. The peak of the student group appeared clearly in the morning, with a dispersed peak obtained during the afternoon. Although the peak of the homemaker group was not precise, it was confirmed that they mainly walked in the afternoon. The worker group also did not participate in leisure-purpose walking, while the elderly group mostly undertook walking for leisure. These walking activity time characteristics of pedestrians are expected to be applied when establishing related pedestrian policies.

The Effect of Multicultural Youth's Cultural Adaptation Stress and National Identity on Dual Cultural Acceptance Attitudes

  • Kim, Jae-Nam
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.10
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    • pp.203-210
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    • 2022
  • The purpose of this study examines to what extent the multicultural youth's dual culture acceptance attitude is significantly affected by cultural adaptation stress and national identity using the data of the MAPS(Multicultural Adolescents Panel Study) conducted by the National Youth Policy Institute. The subject of the study was the first data of the second period of the MAPS, and 2,246 multicultural youth who were enrolled in the fourth grade of elementary school as of 2019 were used as analysis data. As a result of the study, it was found that the attitude to accept dual culture was significantly affected in the order of national identity and cultural adaptation stress. This means that the higher the national identity and the lower the cultural adaptation stress, the higher the attitude toward dual culture. On the other hand, as for the type of multicultural youth, it was found that international marriage families had the lowest attitude toward accepting dual culture. In terms of the size of the area where students live, large cities have the lowest dual cultural acceptance attitude. These results suggest that cultural adaptation stress, national identity, type of multicultural family, and area of residence act as major variables in multicultural youth's dual culture acceptance attitude.

Garden City Strategies as the Development Concept of Planned City - Focused on the Conceptual Master Plan for Solaseado - (신도시 개발 컨셉으로서 정원도시 구현 전략 - 영암·해남 관광레저형 기업도시 솔라시도를 대상으로 -)

  • Lee, Seoyoung;Yu, Jimhin;Jeong, Wookju
    • Journal of the Korean Institute of Landscape Architecture
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    • v.50 no.5
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    • pp.54-68
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    • 2022
  • This study proposes urban development concept and strategies for Garden City, focused on Solaseado, Yeongam Heanam Tourism-Leisure Type Enterprise City in Korea. Understanding that an essential element of a garden is the endless care performed by gardeners, the Garden City development concept suggests applying this idea to making planned cities by cultivating the potential natural landscape of the site in the long run. The meaning of Garden City can be defined in three aspects; an attitude and process of planning a city, a system for constructing the spatial structure of a city, and city branding. A Garden City is a city structured with the spirit of a garden, a city where open space networks become the urban structure, and a city that builds its identity through the landscape, respectively. From this point of view, the research draws development strategies with spatial design examples to embody the Garden City concept in Solaseado by following three steps; establishing the main urban axes, creating city networks through the conjunction of the axes, and categorizing and systematizing open spaces within the city. Consequently, the study shows an alternative urban planning model that extends the concept of a Garden City while maintaining the intrinsic landscape as an urban resource. In addition, the conceptual master plan of Solaseado will structure the urban landscape and park system according to the Garden City strategies.

A Study on the Functions of Urban Health Centers under the Local Autonomy system (지방자치제에서의 도시보건소 기능강화 방안에 관한 연구)

  • 김진삼;박형종;김공현;김병성
    • Health Policy and Management
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    • v.4 no.1
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    • pp.1-24
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    • 1994
  • Recently, two main changes were observed in relation to activities of District Health Centers. One is the rapid increase in the quantity and variety of people's demands for health services due to improvement of income level and the other is an introduction of autonomy in local administration. Unitl recently, the District Health Services were mostly depended on the instructions and orders given by Central Governments, and it would be necessary to prepare for the future implementation of autonomous local administration. Especially, the urban health centers may need more attention than those in rural areas because of their complexity and it would be more difficult in choosing and implementing a most suitable health programs for urban communities. This study was made to find out a feasibl developmental model which could be applicable for the urban bealth centers in Kyeongnam- do area. The most studies relating to health centers activities in the past were made by saking questions to current health center workers, but this study has made an effort to find out the opinions of those who are representing the people in the community. For this study, therefore, the Members of Gity Parliament and Village Headmen from 10 cities is Kyeongnam- do were interviewed for the study and the results obtained were compared to those of health officers. It was found that both Parliament Members and Village Headmen were well aware of the need of health centers, however, they tend to put lower priority for health services in compare with other community activities, and pointed out poor quality of services and lack of public understanding as the problems to be overcome. As to the desirable body for policy decision and implementation of health programs, the Members of Local Parliament think the Local Parliament as ideal, where as Village Headmen prefer health experts, and health officenr prefer District Health Center respectively. The most urgent problems of the District health Centers are mentioned as lack of health manpower. As the results of his study, the followings are suggested for improvement of District Health Services; First : reinforcement of professional health workers, Second : establishment of Community Health Council, Third : strengthening of public health education and support, Fourth : flexibility in Local Autonomy and target system relating to health activities.

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Comparative Study of Metro Service in Korea Using Servicescape (서비스스케이프를 활용한 한국의 지하철 서비스 비교연구)

  • Jia-Xing Long;Sung-Pil Lee
    • Journal of Service Research and Studies
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    • v.12 no.2
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    • pp.48-64
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    • 2022
  • The metro played a role in improving and alleviating the problems of urban ground transportation, promoting rational development of the city and at the same time leading the development of metro-related industries. There is no doubt that it had a double effect of enormous economic and social benefits on the development of the country as a whole. The purpose of this study is to apply the concept of servicescape to the metro and establish the definition of the Metro Servicescape(MSS). To this end, the service space and service facilities of the metro were analyzed, and the existing domestic and foreign literature related to servicescape was studied. First, this study defined the concept of servicescape of metro. Second, 10 elements suitable for the metro service landscape were derived through domestic and foreign service landscape studies. Third, through field surveys and analysis of metros in five cities in Seoul, Busan, Daegu, Daejeon, and Gwangju, the ranking of the current status of the domestic metro servicescapes was 203 Seoul metro, 197 Busan metro, 192 Daegu metro, 178 Gwangju metro, There were 172 metro lines in Daejeon. Among them, the four elements of comfort, sociality, cleanliness, and safety are the same, and accordingly, it seems that each city metro is the same standard. However, the six elements of aesthetics, spatiality, convenience, entertainment, openness and information were found to be different for each city metro. It is expected that the results of this study can provide a reference value for future metro service landscape research.