• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.933-948
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• 2023

Atmospheric aerosols not only have adverse effects on human health but also exert direct and indirect impacts on the climate system. Consequently, it is imperative to comprehend the characteristics and spatiotemporal distribution of aerosols. Numerous research endeavors have been undertaken to monitor aerosols, predominantly through the retrieval of aerosol optical depth (AOD) via satellite-based observations. Nonetheless, this approach primarily relies on a look-up table-based inversion algorithm, characterized by computationally intensive operations and associated uncertainties. In this study, a novel high-resolution AOD direct retrieval algorithm, leveraging machine learning, was developed using top-of-atmosphere reflectance data derived from the Geostationary Ocean Color Imager-II (GOCI-II), in conjunction with their differences from the past 30-day minimum reflectance, and meteorological variables from numerical models. The Light Gradient Boosting Machine (LGBM) technique was harnessed, and the resultant estimates underwent rigorous validation encompassing random, temporal, and spatial N-fold cross-validation (CV) using ground-based observation data from Aerosol Robotic Network (AERONET) AOD. The three CV results consistently demonstrated robust performance, yielding R²=0.70-0.80, RMSE=0.08-0.09, and within the expected error (EE) of 75.2-85.1%. The Shapley Additive exPlanations(SHAP) analysis confirmed the substantial influence of reflectance-related variables on AOD estimation. A comprehensive examination of the spatiotemporal distribution of AOD in Seoul and Ulsan revealed that the developed LGBM model yielded results that are in close concordance with AERONET AOD over time, thereby confirming its suitability for AOD retrieval at high spatiotemporal resolution (i.e., hourly, 250 m). Furthermore, upon comparing data coverage, it was ascertained that the LGBM model enhanced data retrieval frequency by approximately 8.8% in comparison to the GOCI-II L2 AOD products, ameliorating issues associated with excessive masking over very illuminated surfaces that are often encountered in physics-based AOD retrieval processes.

• Land and Housing Review
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• v.3 no.3
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• pp.241-248
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• 2012

Although infrastructure cost comprises the great proportion of residential development cost, all of it tends to be borne by land developers which develop large area. This brings about free-riding by adjacent small development or built-up area, followed by the equity problem in terms of infrastructure development cost sharing and the privatization of development gain. This study aims to establish the method to analyze free-riding on the transportation infrastructure(roads) and investigate empirically how much the free-riding occurs. It sets several development scenarios to calculate the part generated by Bucheon Sangdong district, the case area of this study, of all the traffic flow on the roads. The Network analysis is used to estimate the proportion, by development scenarios, of traffic flow, travel time, and travel cost. As a result, the developer of Bucheon Sangdong district is responsible for 83% of the construction cost of selected roads. The methodology and empirical result of this study would contribute to determine who are liable for the infrastructure facilitation and to estimate how much of the cost the obligators have to share.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.127-142
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• 2024

This study aimed to understand the interrelationships between tree species in plant communities through Plant Social Network (PSN) analysis using a large amount of vegetation data surveyed in an island area belonging to a warm-temperate boreal forest. The Machilus thunbergii, Castanopsis sieboldii, and Ligustrum japonicum, which belong to the canopy layer, Pittosporum tobira and Ardisia japonica, which belong to the shrub layer and Trachelospermum asiaticum and Stauntonia hexaphylla, which belong to the vines, appearing in evergreen broad-leaved climax forest community, showed strong positive association(+) with each other. These tree species had a negative association or no friendly relationship with deciduous broad-leaved species due to the large difference in location environments. Divided into 4 group modularizations in the PSN sociogram, evergreen broad-leaved tree species in Group I and deciduous broad-leaved tree species in Group II showed high centrality and connectivity. It was analyzed that the arrangement of tree species (nodes) and the degree of connection (grouping) of the sociogram can indirectly estimate environmental factors and characteristics of plant communities like DCA. Tree species with high centrality and influence in the PSN included T. asiaticum, Eurya japonica, Lindera obtusiloba, and Styrax japonicus. These tree species are common with a wide range of ecological niches and appear to have the characteristics and survival strategies of opportunistic species that commonly appear in forest gaps and damaged areas. They will play a major role in inter-species interactions and structural and functional changes in plant communities. In the future, long-term research and in-depth discussions are needed to determine how these species actually influence plant community changes through interactions

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.113-130
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• 2002

In this paper, we developed DNL(Dynamic Network Loading) model based on Moving cell theory to analyze the dynamic characteristics of traffic flow in congested network. In this paper vehicles entered into link at same interval would construct one cell, and the cells moved according to Cell following rule. In the past researches relating to DNL model a continuous single link is separated into two sections such as running section and queuing section to describe physical queue so that various dynamic states generated in real link are only simplified by running and queuing state. However, the approach has some difficulties in simulating various dynamic flow characteristics. To overcome these problems, we present Moving cell theory which is developed by combining Car following theory and Lagrangian method mainly using for the analysis of air pollutants dispersion. In Moving cell theory platoons are represented by cells and each cell is processed by Cell following theory. This type of simulation model is firstly presented by Cremer et al(1999). However they did not develop merging and diverging model because their model was applied to basic freeway section. Moreover they set the number of vehicles which can be included in one cell in one interval so this formulation cant apply to signalized intersection in urban network. To solve these difficulties we develop new approach using Moving cell theory and simulate traffic flow dynamics continuously by movement and state transition of the cells. The developed model are played on simple network including merging and diverging section and it shows improved abilities to describe flow dynamics comparing past DNL models.

• Spatial Information Research
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• v.22 no.4
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• pp.89-102
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• 2014

The establishment and operation of Region-based Teleworking Centers(RTC) in Korea is in the initial stage at the moment. Although some studies have been conducted on telecommuting at home, few studies have been performed on the effects of all-out expansion and diffusion of region-based Teleworking Centers. Therefore, this study analyzed the reduction effect of commuting distance which is possible to obtain from the establishment of Teleworking Centers, based on the network in the Seoul Metropolitan Area, Subsequently, quantitative reduction of the effects of $CO_2$ were calculated from region-based Teleworking Centers. The results of the analysis indicated that region-based Teleworking Centers could reduce a total of 911 tons of $CO_2$ per day. When applying these results to 258 working days per year (according to Statistics Korea), 235,056 tons of $CO_2$ can be reduced annually by the establishment of Teleworking Centers. With quantity on environmental utility to be obtained from the establishment of Teleworking Centers, this study can be utilized as a guideline for selecting effective locations of Teleworking Centers in the future. It can also be helpful in decisions to determine the priority of extending operations of Teleworking Centers through comparisons among administrative districts.

• Journal of Korean Society of Rural Planning
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• v.21 no.2
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• pp.11-21
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• 2015

This study carried out evaluation of vulnerability in accessability and functionality using road network that was extracted from Intelligent Transportation System(ITS) and digital map. It was built in order to figure out accessability that locational data which include community center, public facilities, medical facilities and highway IC. The method for grasping functionality are Digital Elevation Model(DEM) and land slide hazard map provided by Korea Forest Service. The evaluation criteria for figure out accessability was set to related comparison of average time in urban area. Functionality value was calculated by the possibility of backing the vehicle possibility of snowfall and landslides. At last, this research computed weighting value through Analytic Hierarchy Process (AHP), calculated a vulnerable score. As the result, the accessability of rural village came out that would spend more time by 1.4 to 3.2 times in comparison with urban area. Even though, vulnerability of the road by a snowfall was estimated that more than 50% satisfies the first class, however, it show up that the road were still vulnerable due snowing because over the 14% of the road being evaluated the fifth class. The functionality has been satisfied most of the road, however, It was vulnerable around Lake Daechung and Piban-ryung, Yumti-jae, Suriti-jae where on the way Boeun. Also, the fifth class road are about 35 km away from the city hall on distance, take an hour to an hour and a half. The fourth class road are about 25 km away from the city hall on distance, take 25 min to an hour. The other class of the road take in 30 min from the city hall or aren't affected of weather and have been analyzed that a density of road is high. In A result that compare between distribution and a housing density came out different the southern and the eastern area, so this result could be suggested quantitative data for possibility of development.

• Journal of Environmental Impact Assessment
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• v.24 no.6
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• pp.593-606
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• 2015

This study was intended to develop Korean Environmental Sustainable City Index (ESCI) so that local governments can examine and identify urban environment issues and then come up with a policy to improve the environment and urban biodiversity for cities. Green City Index (GCI), Environmental Performance Index (EPI), and City Biodiversity Index (CBI) which have used worldwide were analyzed. Based on the result of analysis, evaluation indicators of ESCI were finally a total of 20 indicators under four categories, which are native biodiversity, living environment, ecosystem services, and governance and management. Then, five cities with biotope mapping and evaluation index were selected to apply ESCI for evaluation. In order to apply ESCI, local governments need to accumulate basic data. There should be a policy which requires local governments to build data for biotope mapping so that the rate of natural area, ecological network and permeable land surface can be evaluated. Indicators must be applied to be compliant with scale of the city and level of data building gradually.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.251-258
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• 1998

The purpose of this study is to develop the District-level Planning Support System (DPSS) by using GIS. The district-level planning which is related for district-level control of city, needs the various parcel-level information which is composing the urban physical environment. The information has to be stored and analyzed for recognizing the study area, then the district-level planning will be efficiently managed. The use of GIS in the process of district-level planning is restricted for the creation of thematic map. GIS is not used for the analysis of spatial patterns and planning process. This study evaluates the characteristics of current district-level planning and the basic components of urban physical environment. And the database model is built. The topology among components is defined by using the spatial relationship. Then the spatial query machine for district-level planing is developed by using ArcView 3.1, Avenue and Dialog Extension. This spatial query machine is applied for case study. This study shows 1) the possibility of the district-level planning support system for analyzing spatial relationship, 2) the needs of the up-to-date topographic map showing current building's footlines and the complete integration with cadastral maps, it will reduce the uncertainty in the spatial decision making process, 3) the methodology for the construction of spatial decision making rules, 4) the further study for the using of raster, network, image and three dimension data.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.1
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• pp.1-17
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• 2020

The study aims to identify economic interdependencies between regions and define functional economic areas of Korea by analyzing inter-firm transaction networks. Previous research has relied on pre-given administrative boundaries or cultural homogeneity and used data such as commuting, population movement, and cargo flows which could not fully explain economic activities. To overcome the limitations, this study applies a community detection method to inter-firm transaction networks derived from the CRETOP+ database of Korean corporate data. The novel dataset and the network analysis enables us to identify Korea's functional economic areas based on actual inter-firm linkages. The result shows that there are six to seven economic blocs in the networks as of 2018. In particular, one huge economic bloc is formed integrating the Seoul metropolitan area, Chungcheong, and Gangwon provinces. Meanwhile, North Jeolla and South Jeolla provinces form two economic blocs separately rather than being tied up in one bloc due to the low frequency of transactions between each other. The two big economic blocs of Daegu-Gyeongbuk and Busan-Gyeongnam exist, and interestingly, Ulsan, Gyeongju, and Pohang form a separate middle-sized bloc across the administrative boundaries. The results reveal that the future balanced national development policies should be implemented based on functional economic areas derived from empirical data.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.1
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• pp.9-16
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• 2018

Landscape architecture is an indispensable professional service in building sustainable land and urban environments. The landscape architecture industry is closely related to the promotion of the health and welfare of the people, urban revitalization and residential environment improvement as well as job creation. Despite various public interest values of landscape architecture, the growth engine of the landscape architecture industry, which is supposed to improve the quality of landscape services, has stagnated. In 2015, the Landscape Architecture Promotion Act was enacted to provide a landscape architectural promotion facility and complex system to support revitalization through the integration of the landscape architecture industry. The purpose of this study is to suggest an improvement plan to enhance the effectiveness of the landscape architectural promotion facility and complex system. The results of the analysis are as follows: First, workers and experts in landscape architecture recognized the need for policies and projects to promote the landscape architecture industry. Second, the industrial types suitable for the landscape architectural promotion facility were landscape design, landscape maintenance and management, and landscape construction industry. Meanwhile the industrial types suitable for a landscape architectural promotion complex were landscape trees and landscape facilities production and distribution. Third, the expected effect of the designation of the landscape architectural facility was 'the increase of the business opportunity through the expansion of the network'. On the other hand, that of the landscape architectural promotion complex was 'the activation of various information sharing'. Fourth, 'the size of the local government landscape architecture industry and the capacity to cultivate' was the most important among the designation criteria of the landscape architectural promotion facility. As for that of the landscape architectural promotion complex, the 'feasibility of promotion plan' was the most crucial. Fifth, 'tax benefit and deductible exemption' was considered as a necessary support method for the activation of the landscape architectural promotion facility, and 'maintenance and management fee support' was recognized in the case of the landscape architectural promotion complex.