• Title/Summary/Keyword: Time-series Analysis

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A Study on the Movement of Street-based Urban Morphology Using Analysis of Integrated Land Use-Transportation (토지이용-교통 통합적 분석을 통한 도로 기반 도시 형태학적 변화에 관한 연구)

  • Joo, Yong-Jin
    • Spatial Information Research
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    • v.19 no.3
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    • pp.63-72
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    • 2011
  • Urban space structure tends to have a significant change in accordance with maintenance of urban infrastructure such as a traffic route. For this reason, quantitative analysis has been needed to establish spatial distribution and location patterns by considering change of both road accessibility and urban infrastructure level, which can have the most pervasive influence in urban development process. Therefore, this paper aims to analyze spatio-temporal urban morphology through considering distribution patterns of road among transportation infrastructures, population, and spatial structure of metropolitan areas, focusing on Seoul where population growth and the size of urban area have been dramatically increased. For this, we firstly developed and constructed time-series GIS database by using satellite images and topographic maps of the last 70 years to analyze variables which affect urban growth and transportation. In particular, we analyzed the transform of the system of the street by Space Syntax which is able to grasp hierarchical spatial structure through visibility of space and spatial cognition in terms of accessibility. What's more, we analyzed and visualized the relationship urban morphology and road according the regions of Seoul through IPA(Importance Performance Analysis). In terms of the integration land-use and transportation, Space Syntax approach is expected to contribute to efficient urban planning through understanding the influence which various transportation phenomena has an effect on urban development patterns.

Sensitivity Analysis of Sediment Transport Scaling Factors on Cross-Shore Beach Profile Changes using Deflt3D (해빈 단면의 지형변화 모의를 위한 Delft3D 내의 표사이동 관련 매개변수의 민감도 분석)

  • Yang, Jung-A;Son, Sangyoung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.6
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    • pp.493-500
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    • 2019
  • In this study, sensitivity analysis of sediment transport scaling factors in Delft3D-Morphology was performed to examine the effect those parameters on simulation results of cross-shore profile changes. For numerical experiments, one-year wave time series data which were observed in 2018 on the Maengbang coast in Gangwon prefecture were applied as external force. Bathymetric data observed in January and October of the same year were used as initial bathymetric data and annual bathymetric change data, respectively. The simulation performance of the model was evaluated based on the Brier Skill Score index for each part by dividing an arbitrary cross section within the calculation domain into the onshore and offshore parts. As a result, it was found thet the fBED variable has a slight effect on the simulation results. The fBEDW and fSUSW variables show good simulation performance in onshore part when the value less than 0.5 is applied and vice versa. Among the experimental conditions, the optimal combinations of variables are fBED = 1.0, fBEDW = 1.0, fSUSW = 0.1 for the onshore region and fBED = 1.0, fBEDW = 1.0, fSUSW = 0.5 for the offshore region. However, since these combinations were derived based on the observation data on Maengbang beach in 2018, users should be careful when applying those results to other areas.

Change in the Prevalence of Allergic Diseases and its Association with Air Pollution in Major Cities of Korea - Population under 19 Years Old in Different Land-use Areas - (주요 대도시 알레르기 질환 유병률 변화와 대기오염과의 관련성 - 지역 용도를 고려한 19세 이하 주민 대상 -)

  • Lee, Jiho;Oh, Inbo;Kim, Min-ho;Bang, Jin Hee;Park, Sang Jin;Yun, Seok Hyeon;Kim, Yangho
    • Journal of Environmental Health Sciences
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    • v.43 no.6
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    • pp.478-490
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    • 2017
  • Objectives: The association of air pollution levels and land-use types with changes in the prevalence of allergic diseases (allergic conjunctivitis, allergic rhinitis, asthma, and atopic dermatitis) was investigated for seven metropolitan cities in Korea Methods: Data on daily hospital visits and admissions (of those under 19 years old) for 2003-2012 were obtained from the National Health Insurance Cooperation. Meteorological data on daily mean temperature, humidity, and air pressure were obtained from the Korea Meteorological Administration. Daily mean or maximum concentration data for five pollutants ($PM_{10}$, $O_3$, $NO_2$, $SO_2$, and CO) as measured at air quality monitoring sites operated by the Ministry of Environment were used. We estimated excess risk and 95% confidence intervals for the increasing interquatile range (IQR) of each air pollutant using Generalized Additive Models (GAM) appropriate for time series analysis. Results: In this study, we observed a significant association between the IQR increases of air pollutants and the prevalence risk of allergic diseases (allergic conjunctivitis, allergic rhinitis, asthma, and atopic dermatitis) in all metropolitan cities after adjusting for temperature, humidity, and air pressure at sea level. Among the air pollutants, $NO_2$ and $PM_{10}$ were associated with the prevalence of asthma, and $O_3$ was associated with only allergic conjunctivitis in regression analysis. However, in GAM analysis considering land-use, $O_3$ and $SO_2$ were associated with allergic conjunctivitis, PM10, O3, NO2, and CO were associated with allergic rhinitis, and $PM_{10}$, $O_3$ and $NO_2$ were associated with asthma in industrial area. Conclusion: This study found a significant association between air pollution and the prevalence of allergic related diseases in industrial areas. More detailed research considering mixed traffic-related air pollution (TRAP) and conducting meta-analyses combining data of the all cities is required.

The Factor Analysis of Land Surface Temperature(LST) Change using MODIS Imagery and Panel Data (MODIS 영상 자료와 패널 자료를 이용한 지표면온도변화 요인분석)

  • BAE, Da-Hye;KIM, Hong-Myung;HA, Sung-Ryong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.1
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    • pp.46-56
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    • 2018
  • This paper aimed to identify main factors of community characters, which have an effect on the land surface temperature(LST) change and estimate the impacting coefficient(ratio) of factors in a significant level of statistics. Chungcheongbuk-do province was selected and then partitioned into city and county areas for the sake of convenience of modeling. LST time series data and the community character data were developed based on Terra Satellite MODIS data and collected from the National Statistical Office, respectively. By the cause and effect relationship between community characters and LST, regression coefficients were estimated using a penal model. In a panel modeling, LST and community characters were used as a dependent variable and explanatory variables, respectively. Panel modeling analysis was carried out using statistical package STATA14 and one-way fixed effect model was selected as the most suitable model to evaluate the regression coefficients in the study area. The impacting ratio of LST change by any explanatory variable derived from the regression coefficients of the panel model fixed. Impacting ratios for industrial areas, elevation ${\times}$ building, energy usage, average window speed, non-urban management area, agricultural, nature and environmental conservation, average precipitation were 3.746, 2.856, 2.742, 0.553, 0.102, 0.071 and 0.003, respectively.

Spatial-temporal Variations of Nitrate Levels in Groundwater of Jeju Island, Korea: Evaluation of Long-term (1993-2015) Monitoring Data (제주도 지하수질산염 농도의 시·공간적변화 특성: 장기(1993-2015) 모니터링 자료의 평가)

  • Kim, Ho-Rim;Oh, Junseop;Do, Hyun-Kwon;Lee, Kyung-Jin;Hyun, Ik-Hyun;Oh, Sang-Sil;Kam, Sang-Kyu;Yun, Seong-Taek
    • Economic and Environmental Geology
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    • v.51 no.1
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    • pp.15-26
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    • 2018
  • The spatio-temporal variations of nitrate concentrations in groundwater of Jeju Island were evaluated by an analysis of time series groundwater quality data (N = 21,568) that were collected from regional groundwater monitoring (number of wells = 4,835) for up to 20 years between 1993 and 2015. The median concentration of $NO_3-N$ is 2.5 mg/L, which is slightly higher than those reported from regional surveys in other countries. Nitrate concentrations of groundwater in wells tend to significantly vary according to different water usage (of the well), administrative districts, and topographic elevations: nitrate level is higher in low-lying agricultural and residential areas than those in high mountainous areas. The Mann-Kendall trend test and Sen's slope analysis show that nitrate concentration in mid-mountainous areas tends to increase, possibly due to the expansion of agricultural areas toward highland. On the other hand, nitrate concentrations in the Specially Designated Groundwater Quality Protection Zones show the temporally decreasing trend, which implies the efficiency of groundwater management actions in Jeju. Proper measures for sustainable groundwater quality management are suggested in this study.

The Spectral Characteristics of Climatological Variables over the Asian Dust Source Regions and its Association with Particle Concentrations in Busan (황사 발원지 기후자료의 시계열 특성과 부산지역 먼지 농도의 연관성 분석)

  • Son, Hye-Young;Kim, Cheol-Hee
    • Journal of the Korean earth science society
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    • v.30 no.6
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    • pp.734-743
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    • 2009
  • In order to examine how climatological condition can influence on urban scale particulate air pollutants, single and cross spectrum analysis have been performed to daily mean concentrations of particulate matters ($PM_{10}$) in Busan together with the climatological variables over the Asian dust source regions. Single power spectrum analysis of $PM_{10}$ concentrations in Busan shows that, aside from the typical and well-known periodicities, 3-4 year of peak periodicity of power spectrum density was identified. In cross spectrum analysis, this 3-4 year periodicity is found to have a strong positive correlation with the wind speed and pressure, and negative with the temperature and relative humidity, which is rather consistent with both characteristics of air mass during the Asian dust event whose periodicities have been recorded inter-annually over the Korean urban cities. Over the Asian dust source regions, $PM_{10}$ vs. precipitation shows no significant periodicity from the time series of precipitation data, but the periodicity of EDI (Effective Drought Index) shows some interannual variabilities ranging from 2 to 4 years over the various source regions, suggesting that, rather than precipitation itself, the EDI could be more closely associated with the occurrence frequency of Asian dust and interannual variability of urban particle concentrations in Korean cities.

An Analysis of Teaching Strategies of Science Teacher's Teaching in Science Museum (과학관 학습 실행에서 나타난 과학 교사의 교수 전략 분석)

  • Han, Moonjung;Yang, Chanho;Noh, Taehee
    • Journal of The Korean Association For Science Education
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    • v.34 no.6
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    • pp.559-569
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    • 2014
  • In this case study, we investigated teaching strategies of science teacher's teaching in science museum. Two secondary science teachers who completed a teacher training course on teaching in science museums participated in this study. We conducted interviews about their perceptions on teaching in science museum and their teaching plans before teaching. Then, we observed and recorded their teaching practices in the science museum throughout one semester, and collected all of the teaching materials. The interviews were also conducted after every lessons and at the end of the semester. For the analysis of teaching strategies, we used a framework that was revised from the framework for museum practice (FMP). The analysis of results revealed that the teachers understood the significance of planning the activities in a series of pre-visit, during-visit, and post-visit, so that they structured their teaching as continuous activities, not as an one-time event. However, they showed differences in the extent of connecting the activities with the national science curriculum according to their teaching objectives. In addition, there were differences in strategies such as promoting social interaction, evoking students' curiosity and interest, providing students with choices and control, and inducing engagement and challenge depending on each teacher's perceptions and experiences on teaching in science museum. These results suggest that science teacher education for the professional development of teaching in science museum should systematically provide knowledge and experiences on teaching strategies based on appropriate perceptions on teaching in science museum.

Analysis of Thermal Heat Island Potential by Urbanization Using Landsat-8 Time-series Satellite Imagery (Landsat-8 시계열 위성영상을 활용한 도심지 확장에 따른 열섬포텐셜 분석)

  • Kim, Taeheon;Lee, Won Hee;Han, Youkyung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.4
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    • pp.305-316
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    • 2018
  • As the urbanization ratio increases, the heat environment in cities is becoming more important due to the urban heat island. In this study, the heat island spatial analysis was calculated and conducted for analysis of urban thermal environment of Sejong city, which was launched in 2012 and has been developed rapidly. To analyze the ratio and change rate of urban area, a multi temporal land cover map (2013 to 2015 and 2017) of study area is generated based on Landsat-8 OLI/TIRS (Operational Land Imager / Thermal Infrared Sensor) satellite imagery. Then, we select an TIR (Thermal Infrared) band from the two TIR bands provided by the Landsat-8, which is used for calculating the heat island potential, through the accuracy evaluation of the brightness temperature and AWS (Automatic Weathering Station) data. Based on the selected band and surface emissivity, land surface temperature is calculated and the estimated heat island potential change is analyzed. As a result, the land surface temperature of the high ratio and change rate of urban area was significantly higher than the surrounding area around $3^{\circ}C$ to $4^{\circ}C$, and the heat island potential was also higher around $4^{\circ}C$ to $5^{\circ}C$. However, the heat island phenomenon was alleviated in urban areas with high rate of change that also show high green area ratio. Therefore, we demonstrated that dense urban area increases the possibility of inducing heat island, but it can mitigate the heat island through green areas.

A point-scale gap filling of the flux-tower data using the artificial neural network (인공신경망 기법을 이용한 청미천 유역 Flux tower 결측치 보정)

  • Jeon, Hyunho;Baik, Jongjin;Lee, Seulchan;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.53 no.11
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    • pp.929-938
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    • 2020
  • In this study, we estimated missing evapotranspiration (ET) data at a eddy-covariance flux tower in the Cheongmicheon farmland site using the Artificial Neural Network (ANN). The ANN showed excellent performance in numerical analysis and is expanding in various fields. To evaluate the performance the ANN-based gap-filling, ET was calculated using the existing gap-filling methods of Mean Diagnostic Variation (MDV) and Food and Aggregation Organization Penman-Monteith (FAO-PM). Then ET was evaluated by time series method and statistical analysis (coefficient of determination, index of agreement (IOA), root mean squared error (RMSE) and mean absolute error (MAE). For the validation of each gap-filling model, we used 30 minutes of data in 2015. Of the 121 missing values, the ANN method showed the best performance by supplementing 70, 53 and 84 missing values, respectively, in the order of MDV, FAO-PM, and ANN methods. Analysis of the coefficient of determination (MDV, FAO-PM, and ANN methods followed by 0.673, 0.784, and 0.841, respectively.) and the IOA (The MDV, FAO-PM, and ANN methods followed by 0.899, 0.890, and 0.951 respectively.) indicated that, all three methods were highly correlated and considered to be fully utilized, and among them, ANN models showed the highest performance and suitability. Based on this study, it could be used more appropriately in the study of gap-filling method of flux tower data using machine learning method.

A Study on the Type of Litigation through Analysis of Landscape Precedent (조경 판례분석을 통한 소송의 유형화 연구)

  • Park, Hyun-Bin;Kim, Dong-Pil;Moon, Ho-Kyung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.4
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    • pp.8-18
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    • 2020
  • This study selected landscaping-related precedents among Supreme Court decisions to which the Basic Construction Industry Act and Civil Litigation Act were applied, and divided them by year, by sector type, and by litigation type according to the cause of the litigation, and examined time-series trends and the main characteristics of landscaping-related litigation. As a result of the analysis by year, it became apparent that litigation cases began to appear in earnest in 1977, similar to when landscape licenses were first issued. The types according to the cause of the litigation were analyzed by dividing them into 'planning', 'construction', and 'management'. Among them, 'planning' was the most frequently identified (409 cases). Various precedents were searched according to 'construction', and some of them were found to be due to unclear legal standards related to landscaping. In 'management', cases such as safety accidents and crimes were considered. The users, legal definitions, and purposes of the space served as the basis for judgments. As a result of analysis by case type, there were many administrative landscaping-related cases, and the proportion of criminal cases in the management type was the highest. The results of this study looked at precedents across the entire landscape industry, and it was significant that it provides basic data that could be used by the general public as that they were categorized by field. In the future, amendments to the law and various studies should be conducted to reduce and resolve disputes, and it is necessary to expand the publicity of precedents for this purpose.