Yongjin Joo

An empirical study on sustainable walkability indices for transit-oriented development by using the analytic network process approach

The moving spaces for pedestrians are facilities that have very important functions for urbanities’ comfortable traffic and resting areas. Although research on transit-oriented development (TOD) has recently emerged as an issue, most domestic studies have not addressed comprehensive analysis or concrete inducement techniques when it comes to the effects of TOD. Therefore, a decision support system is needed which assists in policy making systems by analysing quantitative effects concerning major planning factors of TOD, such as transit mode, level of service (LOS), density, diversity of land use and pedestrian-friendly urban design. In this respect, this study is intended to seek ways to consider developing Walkability Indicators that simplify pedestrian environment elements around areas adjacent to subway stations, depending on the types of walking space, with a quantitative index, and evaluating and visualizing the overall degree (in terms of pleasantness and aesthetics) of pedestrian friendliness of the environment, as well as pedestrians’ convenience and accessibility. Accordingly, we measured distribution of the traffic facilities and amenities as well as connectivity of the pedestrian networks quantitatively in order to perform a comprehensive evaluation of the pedestrian environments. To develop a pedestrian environment index, quantifiable parameters such as mobility, safety, convenience, pleasantness and environment-friendliness were organized. As a result, parameters were selected and they are viewed to have the potential to be used as indexes for the development of Geographic Information System (GIS). Twenty-one route segment parameters related to pleasantness and safety, and nine intersection-related parameters were classified into five areas. For setting the weight values of the evaluation criteria obtained from the survey, we employed an analytic network process (ANP). The computed scores using these criteria are classified and normalized according to the levels of pedestrian dependency and, finally, displayed on a map. The proposed system is expected to be applicable in the visualization of pedestrian movements and the evaluation of convenience levels of the pedestrian environments.

Design of a dynamic land-use change probability model using spatio-temporal transition matrix

This study aims to analyze land use patterns using time-series satellite images of Seoul Metropolitan Area for the past 30 years, and present a macroscopic model for predicting future land use patterns using Markov Chain based probability model, and finally examine its applicability to Korea. Several Landsat MSS and TM images were used to acquire land-use change patterns and dynamic land-use change patterns were categorized from the classified images. Finally, spatio-temporal transition matrices were constructed from the classified images and applied them into a Markov Chain based model to predict land-use changes for the study area.

An application of the UrbanSim land price model in Yongsan-gu, Seoul, Korea

The land price model in Yongsan-gu aims to assist the development of an integrated land-use and transport model for Seoul city. The simulation software and modelling approach used is UrbanSim, which is comprised of a number of models. One of these models is the land price model. Factors that affect land prices in urban areas are analyzed, categorized and used to explain spatial differences at 150 m × 150 m grid cells in Yongsan-gu by employing a hedonic regression model. The current model is part of the data development of an UrbanSim model for Seoul city. The data preparation, estimation and modelling results are described in this working paper. This paper hopes to contribute to developing an agent-based large scale land-use and transport model in Korea and surrounding countries.

A study on transformation of urban layout patterns through analysis of spatial relationships with urban street configurations

Spatial structures of large cities are typically complex and dynamic as a result of constant changes to their physical and socioeconomic characteristics. Studying both spatial and temporal forms is important for understanding their structures, as well as forecasting possible future changes in city growth patterns. In this study, we analyze structural changes of Seoul, the capital city of Korea, using physical and socioeconomic factors such as street structure, land use and population. We used 25 administrative sub-regions that have composed Seoul City for 30 years from the 1960s to the 1990s, with the analysis broken down into 10-year increments. We used the space syntax theory for the analysis of the changing structure of Seouls street pattern in smaller resolution than existing methods that have focused on issues of accessibility based on zone levels. First, we analyze the attribute values of space syntax, population density and land uses changed in each administrative area of Seoul in each time period. Next, we examine the relationship between street networks and spatial patterns and evaluate whether development patterns are positive or not. Finally, we present the differences of spatial structures between planned areas and naturally grown areas.

A Review of the Development and Application of UrbanSim Integrated Land-Use and Transportation Model

To analysis and mitigate the accelerated growth of urban complexity, dynamic urbar growth simulation modeling techniques have long been considered by planner and related stakeholder. However, most of the existing techniques to study dynamic urban growth have lack of accuracy at the level of household or land parcel and majority of them remain highly aggregate despite the use of disaggregate calibration methods and essentially static in nature. It is with this in mind, to anticipate the future changes of Seoul Metropolitan Area dynamic micro simulation model “UrbanSim” has undertaken into consideration or Korean perspective since it is operational and have been implemented and used for policy analyses. This paper provides an overview of UrbanSim model conception, its development, a list of application to date, as well as our experiment through Yongsan-Gu in Korea.

Developing a Time-series Visualization Technique using a Temporal GIS Database for Urban Growth Simulation

This study aims to design and develop an urban growth simulation using a temporal GIS database consisting of different forms of spatial data for analyzing urban sprawl phenomena in Seoul Metropolitan Area and Gyeonggi Province. We analyzed the characteristics of spatial data and selected appropriate scales and transformation methods to establish consistent database contents. For this, we first developed and constructed time-series visualization techniques with a temporal GIS database and satellite images and topographic maps of the last 80 years to analyze variables which affect urban growth. The variables are roads, transportation systems, land use, population, and urbanization etc. Then, we implemented the visualization methods for various socio-economic and physical variables using the constructed temporal GIS database. We expect that the proposed technique shall be used in many different purposes such as urban sprawl monitoring, river basin analyses, environmental impact analyses, and hydrological modeling. In addition, while being the basic information for sustainable urban growth and urban land use planning, the developed temporal GIS database can be used in calibrating the current urban model and developing future urban growth models as well.