• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.261-273
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• 2022

This study aims to predict the land use demand of Seongnam-city using system dynamics and to simulate the effect of changes in family structure and land use density adjustment policy on land use demand. This study attempted to construct causal loop diagrams and an analysis model. The changes in land use demand over time were predicted through simulation results. As a result of the analysis, as of 2035, an additional supply of 2.08 km² for residential land and 1.36 km² for commercial land is required. Additionally, the current supply area of industrial land can meet the demand. Three policy experiments were conducted by changing the variable values in the basic model. In the first policy experiment, it was found that when the number of household members decreased sharply compared to the basic model, up to 7.99 km² of additional residential land were required. In the second policy experiment, if the apartment floor area ratio was raised from 200% to 300%, it was possible to meet the demand for residential land with the current supply area of Seongnam-city. In the third policy experiment, it was found that even if the average number of floors in the commercial area was raised from four to five and the building-to-land ratio in the commercial area was raised from 80% to 85%, the demand for commercial land exceeded the supply area of the commercial area in Seongnam-city. This study is meaningful in that it proposes a new analytical model for land use demand prediction using system dynamics, and empirically analyzes the model by applying the actual urban planning status and statistics of Seongnam-city.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.9
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• pp.599-608
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• 2022

Urban air mobility (UAM) equipped with rotor system is subject to ground effect at vertiport during takeoff and landing. The aerodynamic performance of the aircraft in ground effect should be analyzed for the safe operation. In this study, The ground effects on the aerodynamic performance and wake structure of the quadcopter electric vertical takeoff and landing (eVTOL) configuration equipped with coaxial counter-rotating propellers were investigated by using the lattice Boltzmann method (LBM). The influence of the ground effect was observed differently in the upper and lower propellers of the coaxial counter-rotating propeller system. There was no significant change in the aerodynamic performance of the upper propeller even if the propeller height above the ground was changed, whereas the averaged thrust and torque of the lower propeller increased significantly as propeller height decreased. In addition, the amplitude of the thrust fluctuation tended to increase as the propeller height decreased. The propeller wake was not sufficiently propagated downstream and was diffused along the ground due to the outwash flow developed by the ground effect. The impingement of the rotor wakes on the ground and a fountain vortex structure were observed.

• 지역과문화
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• v.7 no.4
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• pp.21-48
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• 2020

The purpose of this study is to analyze how the integrated heritage conservation actually affected the urban economy of historical cities. To this end, this study examined the trends and meanings of an integrated heritage conservation, and a relationship between sustainable urban development and integrated heritage conservation to find out connectivity with urban economy. Before an empirical analysis of domestic policy of integrated conservation of heritage, this study overlooked the system of the preservation and promotion of ancient cities, which can be called integrated heritage conservation system in Korea, and examined how the historic landscape improving project, which is being implemented as part of the policy of the preservation and promotion of ancient cities, actually affected the urban economy. This study empirically identified the impact of the project through a land price analysis of the region. This study focused on analyzing an impact of the project on a price of land in the proximity of subsidized land lot and analyzed the impact through Difference-In-Difference method. In particular, the project effect was analyzed only for the settlement zones among the preservation and promotion zones where the project was carried out, and as a result, it was confirmed that the average price of lands in the proximity of subsidized land increased more over the same period than in the areas where the project was not intensively implemented.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.1-14
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• 2023

High-Frequency Radar (HF-Radar) data of surface currents in Yeongil Bay (a semi-enclosed sea area of the East Sea) was used to investigate the between wind and horizontal surface currents The variation in horizontal and vertical flow of surface currents correlated closely to the water temperature time-series data of densely spaced (1 to 2 m) layers. During the time-series observation period, when the northeast wind prevailed over the entire Yeongil Bay area, a rapid rise in water temperature was recorded across all the layers. Moreover, currents parallel to the wind direction were clearly observed in low-frequency currents of the surface layer. Time-delayed correlation analysis between wind and surface current confirmed that if northeasterly wind blows in Yeongil Bay and continues unidirectionally, a southwestward surface current occured within a short period of time (1 to 2 hours). Convergence and divergence were calculated from the daily average values of low-frequency surface currents. A rapid rise in temperature occurred in the lower layers of water at the observation points, due to the convergence (downwelling) of the surface seawater (relatively high temperature water) associated with the northeasterly wind.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.518-526
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• 2022

The extension of life expectancy due to modernization means an extension of the benefit time for elderly care and disease. However, compared to the increase in the elderly, the attitude of children toward parental responsibility is gradually weakening. These social phenomena bring alienation, hopelessness, and stress to life in old age, and the resulting sense of helplessness leads to suicidal thoughts or intentional death (suicide), becoming a social problem. The intentional death (suicide) of the elderly is a social phenomenon that often occurs around them, and the reality can be seen through the movie. In this study, the main character 'Soyoung' in the movie 'The Woman Who Kills' and the surrounding characters 'Song Old Man', 'Jongsu', and 'Jaewoo' in conversations with the elderly problem and death factors were analyzed in the Matrix. ), and then applied to the 'flow chart of problems in the elderly due to modernization' compiled by Byeong-Woo Lim (2019), to explore the factors of intentional death (suicide). As a result of the analysis, the four elderly were exposed to problems of the elderly such as disease, alienation and loneliness, poverty, and loss. (Suicide) was analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.821-829
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• 2006

Traffic load comprise primary input to pavement design causing pavement damage. therefore it should be proceeded suitable traffic load distribution modeling for pavement design and analysis. Traffic load have been represented by equivalent single axle loads (ESALs) which convert mixed traffic stream into one value for design purposes. But there are some limit to apply ESALs to other roads because it is empirical value developed as part of the original AASHO(American Association of State Highway Officials) road test. There have been many efforts to solve these problems. Several leading country have implemented M-E(Mechanistic-Empirical) design procedures based on mechanical concept. As a result, they established traffic load quantification method using load distribution model known as Axle Load Spectra. This paper details Axle Load Spectra and presents axle load distribution model based on normal mixture distribution function using truck load data collected by WIM system installed in national highway. Axle load spectra and axle load distribution model presented in this paper could be useful for basic data when making traffic load quantification plan for pavement design, overweight vehicle permit plan and pavement maintenance cost plan.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.443-451
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• 2010

This paper proposes the methodology about advisory safety speed based on real-time vehicular data collected from highway. The proposed model is useful information to drivers by appling seamless wireless communication and being collected from ECU(Engine Control Unit) equipment in every vehicle. Furthermore, this model also permits the use of realtime sensing data like as adverse weather and road-surface data. Here, the advisory safety speed is defined "the safety speed for drivers considering the time-dependent traffic condition and road-surface state parameter at uniform section", and the advisory safety speed model is developed by considering the parameters: inter-vehicles safe stopping distance, statistical vehicle speed, and real-time road-surface data. This model is evaluated by using the simulation technique for exploring the relationships between advisory safety speed and the dependent parameters like as traffic parameters(smooth condition and traffic jam), incident parameters(no-accident and accident) and road-surface parameters(dry, wet, snow). A simulation's results based on 12 scenarios show significant relationships and trends between 3 parameters and advisory safety speed. This model suggests that the advisory safety speed has more higher than average travel speed and is changeable by changing real-time incident states and road-surface states. The purpose of the research is to prove the new safety related services which are applicable in SMART Highway as traffic and IT convergence technology.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.484-484
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• 2022

서식지적합도지수(Habitat Suitability Index, HSI)는 어류의 환경생태유량(Environmental Ecological Flow) 산정과 관련해 국내외에서 PHABSIM (Physical Habitat Simulation System)이나 River2D 모형과 같은 생태수리 모형에 적용되고 있으며, 특히 물리적서식지모의시스템은 흐름특성(유량유속, 수심 등)의 변화에 대한 하도구간 내 대표어종의 물리적 서식지 변화를 예측하여 대상 어종에 대한 가용서식지면적(어류가 살 수 있는 서식지 면적, Weighed Usable Area, WUA)유량 관계를 통해 서식에 필요한 최적 유량을 산정하는 데 목적이 있다. 물리적 서식지적합도지수 산정과 화학적 서식지적합도지수 산정방법은 WDFW (Washington Department of Fish and Wildlife, 2004)방법과 IFASG (Instream Flow and Aquatic Systems Group, 1986)의 방법으로 산정하였다. 섬진강에서 2020년에는 3개지점, 2021년에는 2020년 3개지점과 새로운 3개지점에 대하여 각각 4, 5, 6, 9, 10 및 11월에 어류 조사 및 물리적 조건 등에 대하여 현장 모니터링을 실시하였다. 2차년도 동안 모니터링 결과 섬진강에서는 줄납자루, 섬진자가사리, 참중고기, 참몰개, 잉어, 붕어, 칼납자루, 큰납지리, 누치, 모래무지, 피라미, 치리, 블루길, 배스 14종에 대하여 물리적 및 화학적 HSI를 산정하였다. 주요종의 WDFW 방법에 따른 큰줄납자루는 수심 0.3~0.6 m, 유속 0.1~0.4 m/s, 섬진자가사리는 수심 0.2~0.5 m, 유속 0.3~0.7 m/s, 참중고기는 수심 0.4~0.8 m, 유속 0.1~0.6 m/s, 피라미는 수심 0.3~0.7 m, 유속 0.1~0.5 m/s로 산정되었다. IFASG 방법으로 큰줄납자루는 섬진강에서는 수심 0.64 m에서 최대의 출현도를 보였으며, HSI는 0.46~0.83 m, 유속은 0.59 m/s에서 최대의 출현도를 보였고, HSI는 0.38~0.83 m/s, 하상기질의 선호도는 평균입경(𝚽m) -1.14(grevel)에서 최대의 출현도를 보였으며, HSI -3.35~0.65(grevel~sand)로 산정되었다. 화학적 HSI 산정결과 큰줄납자루는 BOD는 1.0 mg/L에서 최대 출현도를 보였고, HSI는 0.7~1.2 mg/L, T-N은 0.925 mg/L에서 최대 출현도를 보이며 HSI는 0.604~1.277 mg/L, T-P는 0.028 mg/L에서 최대 출현도를 보이며 HSI는 0.021~0.034 mg/L, SS는 3.6 mg/L에서 최대 출현도를 보이며, HSI는 2.1~5.2 mg/L의 범위로 산정되었다. 산정된 범위는 환경부 생활환경기준 BOD 매우좋음(Ia)~좋음(Ib), T-P 매우좋음(Ia)~좋음(Ib) 등급으로 각각 확인되었다. 본 과제는 3차년(2022년)이 아직 남아 있어 HSI에 대하여 약간 보정이 있을 것이며, 최종 HSI가 산정이 되면 향후 환경적 기능을 고려한 중장기 정부 정책의 활용성 높은 기초자료가 될 것이다.

• Journal of the Korean Society for information Management
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• v.40 no.4
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• pp.403-428
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• 2023

This study investigates the development path and intellectual structure of data literacy research, aiming to identify emerging topics in the field. A comprehensive search for data literacy-related articles on the Web of Science reveals that the field is primarily concentrated in Education & Educational Research and Information Science & Library Science, accounting for nearly 60% of the total. Citation network analysis, employing the PageRank algorithm, identifies key papers with high citation impact across various topics. To accurately trace the development path of data literacy research, an enhanced PageRank main path algorithm is developed, which overcomes the limitations of existing methods confined to the Education & Educational Research field. Keyword bibliographic coupling analysis is employed to unravel the intellectual structure of data literacy research. Utilizing the PNNC algorithm, the detailed structure and clusters of the derived keyword bibliographic coupling network are revealed, including two large clusters, one with two smaller clusters and the other with five smaller clusters. The growth index and mean publishing year of each keyword and cluster are measured to pinpoint emerging topics. The analysis highlights the emergence of critical data literacy for social justice in higher education amidst the ongoing pandemic and the rise of AI chatbots. The enhanced PageRank main path algorithm, developed in this study, demonstrates its effectiveness in identifying parallel research streams developing across different fields.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.108-126
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• 2023

In this paper, the dynamic hard shoulder running for bus only (HSRFBO) was presented to solve the traffic congestion by increase the capacity in chronic congested sections of highways, and a simulation was performed to evaluate the comparison with the current hard shoulder running for all vehicles(HSRFAV) and median bus only lane and HSR(MBOLHSR). According to the evaluation results, it was evaluated to be more advantageous in terms of traffic flow and safety than the current HSRFAV. In addition, the speed of passing buses is slightly reduced compared to the MBOHSR, but the speed of entering and exiting buses is increased and the speed of buses and cars is greatly improved. Therefore It was analyzed that the efficiency of transport personnel was also improved. In particular, it is expected that traffic flow will be stabilized as the difference in speed between passenger cars and buses will be greatly reduced, and violations of exclusive bus lanes by passenger cars will be greatly reduced. In addition, the operation time of HSR is greatly reduced, so that the original function of the shoulder lane can be maintained as much as possible. As a result, it was analyzed that the risk of accidents was significantly reduced when operating HSRFBO compared to when operating MBOHSR, and cross-conflicts with high accident severity did not occur.