• Journal of Internet Computing and Services
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• v.25 no.4
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• pp.23-37
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• 2024

Digital twin is an M&S (Modeling and Simulation) technology designed to solve or optimize problems in the real world by replicating physical objects in the real world as virtual objects in the digital world and predicting phenomena that may occur in the future through simulation. Digital twins have been elaborately designed and utilized based on data collected to achieve specific purposes in large-scale environments such as cities and industrial facilities. In order to apply this digital twin technology to real life and expand it into user-customized service technology, practical but sensitive issues such as personal information protection and personalization of simulations must be resolved. To solve this problem, this paper proposes a federated learning-based accelerated client training method (FACTS) for personalized digital twins. The basic approach is to use a cluster-driven federated learning training procedure to protect personal information while simultaneously selecting a training model similar to the user and training it adaptively. As a result of experiments under various statistically heterogeneous conditions, FACTS was found to be superior to the existing FL method in terms of training speed and resource efficiency.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.4
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• pp.35-50
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• 2023

As urbanization progresses, there is a growing and continuous demand for green spaces that provide ecosystem services. However, increasing the quantity of green spaces within major cities is challenging. Therefore, it is essential to pursue qualitative improvements that consider ecological characteristics of existing green spaces. In this study, we focus on local neighborhood parks in Seoul and present the following two questions through an evaluation utilizing ecological design indicators and land use data: 1. Which factor, design or location, has a greater influence on the ecological quality of neighborhood parks in Seoul? 2. Additionally, when evaluating ecological characteristics, is there similarity between assessments based on land-use data and those utilizing ecological design indicators? For this study, we conducted research on 30 neighborhood parks in Seoul and classified them into mountainous types (adjacent to mountains, natural terrain parks) and urban types (independently designed within 300m without existing forests) based on previous studies. Firstly, we conducted evaluations according to park location types. When comparing the evaluation scores of urban types (14 parks) and mountainous types (16 parks), significant differences were observed with scores of 16.86 and 35.94, respectively. Statistical analysis showed a significant difference between park types. In terms of habitat quality, the average values for urban and mountainous parks were 0.33 and 0.53, respectively, and statistically significant differences were observed between park types indicating differences in ecological potential according to park location. Secondly, when comparing the results of ecological potential evaluations based on park design and external connectivity, a correlation was found between habitat quality and total scores according to evaluation indicators. The correlation analysis showed significant linear relationships between habitat quality and total scores, biodiversity scores, and ecosystem function scores, with high positive correlation coefficients of 0.829, 0.861, and 0.802, respectively. This study holds significance in analyzing the ecological aspects of urban parks through the lens of both park location characteristics and design indicators. The analysis results underscore the importance of planning and managing ecologically sound urban parks contingent upon their location. Moreover, the utilization of appropriate ecological design indicators can help alleviate environmental limitations surrounding parks. Integrating these considerations could enhance the ecological quality and ecosystem services of urban green spaces.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.431-447
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• 2024

This study aims to analyze the supply and demand trends and regional distribution characteristics of the stone industry through transaction records of the domestic natural stone market. The demand for natural stone is increasing globally, but domestic stone producers are facing financial difficulties due to the influx of low-cost stone, and the government is implementing various support policies, such as mandating the use of domestic stone. However, the influx of low-cost stones has led to management deterioration for domestic stone producers, prompting the government to implement various support policies such as mandating the use of domestic stones. An analysis of the natural stone transaction records from the Public Procurement Service revealed that granite was the main type of rock. The main trading items were natural stone curbs and natural stone slabs, with an average annual transaction amount of approximately 312.8 billion KRW from 2017 to 2021. A comparison of the stone distribution status between the metropolitan area and non-metropolitan areas showed that the metropolitan area had high demand, while non-metropolitan areas served as major supply sources. Cities such as Pocheon in Gyeonggi-do, Iksan in Jeollabuk-do, and Geochang in Gyeongsangnam-do play important roles as major stone suppliers. Based on these results, this study proposes fostering the stone industry tailored to regional characteristics, diversifying distribution channels, and establishing a sustainable supply chain for the sustainable development of the stone industry. Additionally, it emphasizes the need for close cooperation and support among the government, industry, and research institutions.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.285-294
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• 2023

The importance of urban green space creation is increasingly recognized as the most realistic and efficient approach for fine dust mitigation in urban areas. Particularly considering the characteristics of domestic cities, the application of buffer green spaces along roads can maximize the efficiency of fine dust reduction without the need for separate green space creation. Accordingly, this study analyzed the fine dust mitigation effects based on the types of plantings in the central dividers and roadside trees in Jeonju City, Jeollabuk-do. To do this, we controlled various external variables of urban space and considered the planting arrangement types in the central dividers, carrying out the analysis using a CFD simulation. The simulation results confirmed that the central dividers with plantings demonstrated more effective ultrafine dust reduction than those without. Moreover, the arrangement of roadside trees showed a greater ultrafine dust reduction effect when adopting a multilayered structure compared to a single layer. Based on these findings, we concluded that installing both trees and shrubs simultaneously in the central dividers and along roads was effective for ultrafine dust mitigation. On this basis, we quantified the dust reduction effects of plants in urban street environments and proposed planting guidelines for roadside green spaces to improve air quality.

• Journal of the Korean Regional Science Association
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• v.40 no.3
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• pp.63-74
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• 2024

Ths study aims to analyze the economic impact of smart city construction project and operation project on the regions. The study used case studies to analyze the economic impact of smart city construction projects such as Busan EDC and Sejong 5-1, and operation projects such as Jeonju and Daejeon smart city plans. The study used a regional input-output model as its analysis model. The data used for the analysis was the 2015 regional input-output table published by the Bank of Korea. The industry was reclassified from 83 mid-category industries into 8 industries. The analysis results are summarized as follows. First, the construction project of smart cities was found to have a spillover effect (production inducement effect) not only in Seoul and Gyeonggi Province, but also in the surrounding areas of the target regions such as Gyeongnam (Busan EDC) and Chungnam (Sejong 5-1). Second, smart city operation projects had the greatest impact (production, value-added and employment) on the target areas (Daejeon and Jeonju), but the proportion of economic impact in regions other than Seoul and Gyeonggi was low. Third, the ripple effect was more concentrated in the Seoul and Gyeonggi regions when the smart city operation project was promoted rather than the smart city construction project. This is due to the concentration of major smart city-related companies, industrial clusters, and research and development infrastructure in the Seoul and Gyeonggi regions.

• 산업혁신연구
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• v.34 no.2
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• pp.153-186
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• 2018

Technological innovation is a key driver of firm survival and prosperity in a competitive market. Though most economists consider the determinants of technological innovation as firm-level activities, concentrations of innovative performance within particular regions have been observed almost everywhere. We examine if performance of technological innovation for photonics industry in Korea will be affected by different regions as well as firm specific factors. By applying Heckman's selection model, we found that specific regions such as Gwangju and Honam region have significant effects on the probability of obtaining patents, but there is no significant evidence that the location on specific regions increases the number of patents. On the contrary, firms with main plants in the SMA have not only significantly lower chances of obtaining patents but also produce significantly fewer patents than do firms in other regions. The analysis also found that the R&D spending-capital ratio, total employment-capital ratio of firms, and firm location in metropolitan cities are all positively related to the number of patents. As a policy implication, more active cooperation between the R&D cluster and the surrounding firms will be required to enhance the technology diffusion effects from the R&D cluster to innovative activity of the firms. This paper contributes relevant literature by showing empirically that regional location is an important determinant of technological innovation for photonics firms.

• 한국프랑스학논집
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• v.108
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• pp.269-297
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• 2019

This article is to examine the characteristics of the first foundation of the Islamic Maghreb dynasty through the city of Tlemcen and its characteristics of the dynasty. This shows that primitive Islam in the French-speaking Maghreb region is based on a singular Islamic doctrine. Similarly, looking at the Islamic dynasty of Tlemcen, which was the center of Andalusian culture in the Middle Ages, we examined the status of Tlemcen as an Andalusian cultural center. Tlemcen, which was chosen as the capital of Islamic culture in 2011 by inheriting the Andalusian tradition, is as important in its identity as in its historicity. Because this Maghreb city has helped to Islamize the Iberian Peninsula. Tlemcen also has active exchanges with Mediterranean cities and has also imported and disseminated various cultures. Although the cult of trade has changed depending on power, this city has played the most important role of the Mediterranean Sea by continually expanding its functions and spreading various cultures in sub-Saharan Africa. At the time, it was the Ziyanide dynasty that was in the center and it has important historical values ​​in the sense that it is now the homeland of Algeria. By examining the region of Tlemcen, which is of religious and cultural importance, it was possible to examine the expansion of Andalusian culture in Algeria and the attributes of primitive Islam in the Maghreb.

• Knowledge Management Research
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• v.25 no.3
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• pp.231-251
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• 2024

For Airbnb, one of the most successful examples of the sharing economy, to continuously grow, it needs a steady supply of attractive listings. To this end, this study draws on existing research on Airbnb and signaling theory to examine the factors that influence the performance of Airbnb listings. From a dynamic perspective, we expect the importance of factors affecting listings' performance to differ between new and existing listings. Analyzing Airbnb data from the 10 most active US cities using negative binomial regression, we find that dynamic attributes that require a time investment have a stronger impact on existing listings, while static attributes that require less of a time investment have a similar effect on both types. The host's membership duration and number of listings were expected to have positive effects, but showed negative effects. While the instant booking policy increased users' convenience, some hosts were reluctant to use it. The results of the analysis suggest that the importance of the factors varies depending on the type of Airbnb listing (new vs. existing), and the need for differentiated policies and complementary measures based on the type of listing is necessary in a practical perspective.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.42 no.2
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• pp.20-32
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• 2024

The purpose of this study was to divide cultural assets distributed in Shandong Province, China into five periods and identify the spatial distribution of each cultural asset type and its relationship with the natural environment, such as elevation, slope, and water system. As a result of the study, cultural properties before the Jin dynasty had a high distribution ratio of urban relics such as villages and tombs, and in Jin·Han~Su·Tang dynasty, tombs, ruins, stone caves, and stone carvings. In the Song and Yuan dynasties, there were many cultural properties such as relics, architectural and landscape cultural properties, and in the Ming and Qing dynasties, there were many cultural properties such as buildings, and they were more spatially distributed and distributed. After the Qing Dynasty, commemorative sites, political and defense-related buildings were distributed throughout Shandong, and many cultural assets were located in coastal cities on the east side of Shandong Province. It was found that the types of cultural assets were influenced not only by the social environment of each era but also by the natural environment. Except for cultural assets related to religion, such as grottoes and stone carvings, most cultural assets were located at low elevations and low slopes, and cultural assets were often distributed within 5km of water systems.

• Journal of School Social Work
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• v.42
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• pp.237-261
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• 2018

The purpose of the present was to verify the four-factor model and the high-order four-factor model of the CES-DC 11 (Center for Epidemiological Studies Depression Scale Children) scale used to measure depression of adolescents in Korea. For this purpose, data were collected randomly from 193 middle school third grade student in large-scaled cities. The collected data were identified their measurement invariance through various data analysis techniques, reliability analysis, confirmatory factor analysis, and high-order factor analysis. The main results of this present are as follows. First, the confirmatory factor analysis and the high-order factor analysis showed that the CES-DC 11 scale was a suitable model for both the four-factor model and the higher-order 4 factor. Second, the CES-DC 11 scale showed that both the four-factor model and the higher-order 4-factor model maintained the measurement invariance between male and female groups. Therefore, the researcher adopted the high-order four factor model as the most suitable final model. The results of this study show that the Korean version CES-DC 11 scale is a highly reliable and valid scale avaliable regardless of sex in measuring the depression of adolescents in Korea. It is suggested that this scale can be used for comparing the male and female adolescent groups with depression in future studies. A suggestion is presented for specific discussions and follow-up studies.