Papers by Chang-Hyeon Joh
Daehan gyotong haghoeji, Dec 31, 2017
This study aims to evaluate the availability of ABM (Active-Based Model), FEATHERS, as a policy e... more This study aims to evaluate the availability of ABM (Active-Based Model), FEATHERS, as a policy evaluation tool. To achieve the goal, scenario analysis on flexible working policy was conducted to measure its impact on activity-travel behavior. As a consequence, there seems no significant change in worker's daily life, other than mitigating traffic congestion due to decreasing commuting travel in the rush hour. The result of VKT (vehicle kilometers traveled) shows an opposite pattern according to given household/individual constraints. The scenario analysis on telecommuting indicates a decreasing trend in both travel frequency and distance because of the diminished number of commuting trips. As the activity space of telecommuters is shifted to a residential area, there are more short-distance trips by using non-motorized transport, which leads to decrease in VKT (using a private vehicle). Thus, the sensitivity of VKT by population groups varies due to transport mode shift (between personal and another mode) and growing non-work trips (using a private mode). This study found few things. First, it is necessary to evaluate the details of policy impact by population groups since it can be varied depending on household/individual characteristics. Second, the case study shows a promising performance of ABM as policy measurement that provides reality in policy evaluation. Third, ABM allows us to do more accurate analysis (i.e. time-series analysis by population groups) of policy assessment than those of FSM (Four-Step Model). Lastly, a further effort in data collection, literature review, and expert survey should be made to enhance the accuracy and confidence of future research.
Daehan gyotong haghoeji, Oct 31, 2014
Research on activity-based travel demand forecasting and activity-travel simulator has invited an... more Research on activity-based travel demand forecasting and activity-travel simulator has invited an international attention for the last two decades. Ways to develop the activity-based simulator may be manifold. It is obvious that importing an existing simulator that has been proven internationally likely reduces the development cost and the risk of failure. By definition of the activity-based approach, however, the details of an activity-based simulator inevitably relies on particular social, economic and cultural characteristics of the society where the simulator is developed. When importing such a simulator from overseas, the researcher should be aware of the importance of tuning the system for the society to which the imported system is applied. There are many potential works on this, including for example the tuning of data structure that is likely different form that of the original system. We authors do not aware of any research report on this yet. The current paper aims to report the result of research to transform the input data for applying an existing overseas activity-travel simulator to Seoul Metropolitan Area. To this end, the paper first introduces FEATHERS that was developed in Belgium having Albatross at the core of the system. FEATHERS Seoul that is under development to apply original FEATHERS to Seoul is briefly described and the related problems of data structure mismatching are discussed. The paper then reports the effort to alleviate the problems and the results.
Travel Behaviour Research
This paper describes the results of a comparative analysis of three activity-based travel demand ... more This paper describes the results of a comparative analysis of three activity-based travel demand models. Considered are ALBATROSS, a rule-based model, and PCA TS and LLPM -both sequential/nested logit models. The activity diary data used was split into an estimation and an holdout set. The models are estimated independently of each other on the estimation set. Various measures of goodness-of-fit are used to assess the ability of the models to predict the observed activity-travel patterns of the holdout set. The paper discusses the measures of goodness-of-fit and the results of the comparison. (a) For the covering entry of this conference, please see ITRD abstract no. E213535.
Traffic and Mobility, 1999
This paper discusses some experiences with the development of ALBATROSS, a rule-based system for ... more This paper discusses some experiences with the development of ALBATROSS, a rule-based system for predicting transport demand, currently under development for the Dutch Ministry of Transport, Public Works and Water Management. The model belongs to the class of activity-based models, implying that it attempts to predict which activities are conducted where, when, with whom, for how long, and the transport mode involved. In principle, this increased complexity allows one to predict the impact of urban and transport policies and institutional change on activity patterns and hence transport demand, but this increased complexity also involves new theoretical, and methodological challenges and problems of data collection. Some of these challenges are briefly discussed in this paper. In particular, the conceptualisation of activity behaviour, the derivation of choice heuristics from diary data, the development of appropriate goodness-of-fit measures and the problem of data quality are discussed.
Geographical Analysis, 2020
Classification of similar travel behavior is essential for market segmentation research in geogra... more Classification of similar travel behavior is essential for market segmentation research in geography and transportation science. Cluster analysis using sequence alignment measurement incorporates the sequential information embedded in activity‐travel sequences. The resultant clusters are then typically associated with the relevant variables. However, although the sequences are clustered by similar sequential information, the summary of the clusters do not reflect the sequential information with scientific rigor. This is because of the non‐numeric characteristics of the sequential information. The study aims to develop a method for finding a representative sequence (RepSeq) that better profiles the cluster of sequences. The suggested method employs a genetic algorithm to search for a sequence potentially closest to the centroid by computing the smallest sum of distances from the searched sequence to all sequences of the cluster using a sequence alignment method. The suggested method ...
Geographical Analysis, 2019
The article develops a new method that compares activity‐travel patterns in both terms of the seq... more The article develops a new method that compares activity‐travel patterns in both terms of the sequential order of activities and the shape of activity‐travel trajectory in time and space. The similarity of the list of activities and their order between activity‐travel patterns are computed by a sequence alignment method. The shape of activity‐travel trajectory is compared between the patterns using a path similarity technique that captures the direction and speed of a movement from the current location and the duration of staying at each location. The comparison results, therefore capture how people move around in three‐dimensional space–time choreography that indicates how people conduct which activities in what order. A total of 1,000 individuals are sampled from the data of 2016 Household Travel Survey, South Korea. The data provide the information of individual activity‐travel behavior and personal characteristics. The suggested method computes the pairwise distance matrix, and ...
Journal of Korean Society of Transportation, 2017
This study aims to evaluate the availability of ABM (Active-Based Model), FEATHERS, as a policy e... more This study aims to evaluate the availability of ABM (Active-Based Model), FEATHERS, as a policy evaluation tool. To achieve the goal, scenario analysis on flexible working policy was conducted to measure its impact on activity-travel behavior. As a consequence, there seems no significant change in worker's daily life, other than mitigating traffic congestion due to decreasing commuting travel in the rush hour. The result of VKT (vehicle kilometers traveled) shows an opposite pattern according to given household/individual constraints. The scenario analysis on telecommuting indicates a decreasing trend in both travel frequency and distance because of the diminished number of commuting trips. As the activity space of telecommuters is shifted to a residential area, there are more short-distance trips by using non-motorized transport, which leads to decrease in VKT (using a private vehicle). Thus, the sensitivity of VKT by population groups varies due to transport mode shift (between personal and another mode) and growing non-work trips (using a private mode). This study found few things. First, it is necessary to evaluate the details of policy impact by population groups since it can be varied depending on household/individual characteristics. Second, the case study shows a promising performance of ABM as policy measurement that provides reality in policy evaluation. Third, ABM allows us to do more accurate analysis (i.e. time-series analysis by population groups) of policy assessment than those of FSM (Four-Step Model). Lastly, a further effort in data collection, literature review, and expert survey should be made to enhance the accuracy and confidence of future research.
This paper describes the conceptual development, operationalization and empirical testing of Alba... more This paper describes the conceptual development, operationalization and empirical testing of Albatross: A Learning Based Transportation Oriented Simulation System. This activity-based model of activity-travel behavior is derived from theories of choice heuristics that consumers apply when making decisions in complex environments. The model, one of the most comprehensive of its kind, predicts which activities are conducted when, where, for how long, with whom, and the transport mode involved. In addition, various situational, temporal, spatial, spatial-temporal and institutional constraints are incorporated in the model. The decision tree is proposed as a formalism to represent an exhaustive set of mutual exclusive rules for each decision step in the model. A CHAID decision tree induction method is used to derive decision trees from activity diary data. The case study conducted to develop and test the model indicates that performance of the model is very satisfactory. We conclude therefore that the methodology proposed in this article is useful to develop computational process models of activity-travel choice behavior.
Transportation Research Record: Journal of the Transportation Research Board, 2000
The development of a conceptual framework to build a model of multi-faceted choices underlying ac... more The development of a conceptual framework to build a model of multi-faceted choices underlying activity behavior is described. The conceptual framework views individuals developing stereotype behavior or scripts over time by learning. Various principles of learning as a function of state-dependent variables and as a function of latent behavior and adjustment principles are developed and formalized. The focus is on modeling long-term dynamics in activity choice heuristics. Theory, illustrated by a set of numerical experiments, is developed.
Proceedings ICTSC …, 2008
... is too small to describe patronage-patterns at the level of individual destinations (except f... more ... is too small to describe patronage-patterns at the level of individual destinations (except for the large department stores). ... approach of pedestrians providing with GPS-or RFID-equipment and the like when they enter the study area might ... Retail location: a micro-scale perspective ...
… Proceedings of the 9th …, 2001
Abstract: The development of activity-based models of transport demand constitutes one of the mos... more Abstract: The development of activity-based models of transport demand constitutes one of the most rapidly growing fields of interest in transportation research. Originating from the earlier human activity analysis framework developed in the early 1970's, activity-based models explicitly recognize the derived nature of travel as the need to participate in spatially disperse activities. Much of the popularity of these models lie in their ability to model and predict more specific and detailed travel demand management measures, such as longer ...
Understanding activity scheduling and rescheduling behaviour: Theory and
conference; IGU World Conference; 2000-08-13; 2000-08-18, 2000
Journal of the Korean Geographical Society, 2011
Estimating non-linear utility functions of time use in the context of an activity schedule adapta... more Estimating non-linear utility functions of time use in the context of an activity schedule adaptation model
In-vehicle congestion of the urban railway system is the most important indicator to reflect the ... more In-vehicle congestion of the urban railway system is the most important indicator to reflect the operation state of the urban railway. To provide the good service quality of urban railway, the crowdedness of the urban railway should be managed appropriately. The weather is one of the critical factors for the crowdedness. That is because even though the crowdedness of the urban railway is the same, passengers feel more uncomfortable in rainy weather condition. Indeed if specific sections and stations suddenly are concentrated excessive demand, it will lead far more serious problem. Therefore, this study analysis the relationship between the number of urban railway passenger and rainfall intensity in Seoul metropolitan subway system and then conducts the spatial analysis to deduct passenger demand patterns. This study is expected to be useful base study in order to manage the congestion at the urban railway station effectively by considering the different rainfall intensity.
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Papers by Chang-Hyeon Joh