Browsing by Author "Wong, K. I."

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An agent-based model for queue formation of powered two-wheelers in heterogeneous traffic
(2016-11-01)
Lee, Tzu-Chang
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Wong, K. I.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This paper presents an agent-based model (ABM) for simulating the queue formation of powered two-wheelers (PTWs) in heterogeneous traffic at a signalized intersection. The main novelty is that the proposed interaction rule describing the position choice behavior of PTWs when queuing in heterogeneous traffic can capture the stochastic nature of the decision making process. The interaction rule is formulated as a multinomial logit model, which is calibrated by using a microscopic traffic trajectory dataset obtained from video footage. The ABM is validated against the survey data for the vehicular trajectory patterns, queuing patterns, queue lengths, and discharge rates. The results demonstrate that the proposed model is capable of replicating the observed queue formation process for heterogeneous traffic. (C) 2016 Elsevier B.V. All rights reserved.
AN ESTIMATION OF EFFICIENT TIME-VARYING TOLLS FOR CROSS HARBOR TUNNELS IN HONG KONG
(2011-12-01)
Hau, Timothy D.
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Loo, Becky P. Y.
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Wong, K. I.
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Wong, S. C.
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運輸與物流管理系註：原交通所+運管所
This work estimates the distribution of a time-varying toll over a 24-hour period that minimizes the combined queue length of the three tunnels that traverse Hong Kong's Victoria Harbour, taking into account institutional constraints. Our results reveal that switching from a flat toll to a time-varying toll scheme would eliminate all existing tunnel queues. We argue that optimal tunnel tolling, coupled with the nonstop electronic toll collection mechanism already in place, could be the first step toward the implementation of electronic road pricing in Hong Kong. Optimal tolling would obviate the need to build a fourth harbor crossing in the near future.
Connectivity evaluation of large road network by capacity-weighted eigenvector centrality analysis
(1970-01-01)
Ando, Hiroe
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Bell, Michael
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Kurauchi, Fumitaka
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Wong, K. I.
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Cheung, Kam-Fung
The methods to evaluate the robustness of a network have been extensively studied. Such methods often require obtaining traffic equilibrium conditions or solving mathematical problems, and these methods can only be applied to a network of limited size. On the other hand, nowadays detail road network data can be downloaded freely, and such data may provide different insights on network robustness evaluation. This paper applies the capacity-weighted eigenvector centrality method to identify the strongly and weakly connected parts of large networks. The eigenvector centrality is one of the evaluation methods based on network topology with a small computational load. This method can be applied to directed networks and does not require their adjacency matrices to be symmetric. Several numerical examples showed that the capacity-weighted eigenvector centrality analysis can identify the strongly and weakly connected parts of the network, and it can be used to evaluate connectivity of network for robustness.
Contagion Effect in International Trade After the Japanese 311 Earthquake
(2018-01-01)
Huang, Yu-Che
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Hsu, Chaug-Ing
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Wong, K. I.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This study investigates spatial contagion on trading markets when an industrialized country is stricken by a natural disaster. We present a test for contagion effects on the cargo trading among the major trading partners. The test is based on a comparison of the correlation coefficients of transnational trade linkages in industrial cargo volumes before and after a disaster. Using the Japanese 311 earthquake in 2011 as a case study, the results show that spatial contagion is observed for neighboring countries exporting to Taiwan. It also found that the occurrence of contagion effect depends on the industrial market share of the linkages, and the contagion effect disperses over time.
HEAD MOTION RECOGNITION USING A SMART HELMET FOR MOTORCYCLE RIDERS
(2019-01-01)
Wong, K. I.
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Chen, Yi-Chung
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Lee, Tzu-Chang
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Wang, Sheng-Min
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運輸與物流管理系註：原交通所+運管所
This paper presents a head motion detection and recognition study using a smart helmet for motorcycle rider which can potential be used for the analysis of behavior of motorcycle riders. The smart helmet is a full face motorcycle helmet integrated with an intelligent system embedded an Inertial Measurement Unit (IMU) sensor. In the analysis, the motions and the corresponding signals are assessed with the video footage with a data acquisition and visualization platform. We introduce a feature extraction methodology to extract the most discriminant features from the signal data, and the head motion recognition problem is formulated as a machine-learning based classification model. Experiment results show that gyroscope sensor data is more useful than accelerometer sensor data for head motion recognition and the classification accuracy for different head motions ranges from 95.9% to 99.1%.
HIGHLIGHTS OF THE 2009 TRAVEL CHARACTERISTICS SURVEY OF MACAO
(2009-01-01)
Wan, I. M.
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Wong, K. I.
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Kou, K. P.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
Modeling urban taxi services with multiple user classes and vehicle modes
(2008-12-01)
Wong, K. I.
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Wong, S. C.
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Yang, Hai
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Wu, J. H.
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運輸與物流管理系註：原交通所+運管所
This paper extends the model of urban taxi services in congested networks to the case of multiple user classes, multiple taxi modes, and customer hierarchical modal choice. There are several classes of customers with different values of time and money, and several modes of taxi services with distinct combinations of service area restrictions and fare levels. The multi-class multi-mode formulation allows the modeling of both mileage-based and congestion-based taxi fare charging mechanisms in a unified framework, and can more realistically model most urban taxi services, which are charged on the basis of both time and distance. The introduction of multiple taxi modes can also be used to model the differentiation between luxury taxis and normal taxis by their respective service areas and customer waiting times. We propose a simultaneous mathematical formulation of two equilibrium sub-problems for the model. One sub-problem is a combined network equilibrium model (CNEM) that describes the hierarchical logit mode choice model of occupied taxis and normal traffic, together with the vacant taxi distributions in the network. The other sub-problem is a set of linear and nonlinear equations (SLNE), which ensures the satisfaction of the relation between taxi and customer waiting times, the relation between customer demand and taxi supply for each taxi mode, and taxi service time constraints. The CNEM can be formulated as a variational inequality program that is solvable by means of a block Gauss-Seidel decomposition approach coupled with the method of successive averages. The SLNE can be solved by a Newtonian algorithm with a line search. The CNEM is formulated as a special case of the general travel demand model so that it is possible to incorporate the taxi model into an existing package as an add-on module, in which the algorithm for the CNEM is built in practice. Most of the parameters are observable, given that such a calibrated transport planning model exists. A numerical example is used to demonstrate the effectiveness of the proposed methodology. (C) 2008 Elsevier Ltd. All rights reserved.
Nonlinear pricing of taxi services
(2010-06-01)
Yang, Hai
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Fung, C. S.
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Wong, K. I.
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Wong, S. C.
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運輸與物流管理系註：原交通所+運管所
This paper examines the effects of nonlinear fare structures in taxi markets using an extended taxi model with an explicit consideration of perceived profitability. The expected profit, defined as the profit per unit time (inclusive of both occupied and vacant taxi times), that a taxi driver expects to receive from picking up a customer in a particular zone or location, has great impact on the taxi driver's choice of location in the search for customers. The fare structure directly governs the profitability of taxi rides of different distances originating from different locations. With these explicit considerations, the extended model is intended to look into the market effects of adopting a nonlinear fare structure with declining incremental charges. The proposed nonlinear fare structure could help restore a level-playing field for taxi operators whose businesses have been affected by some taxi drivers who resort to practices such as offering fare discounts or accepting requests for discounted fares from passengers for long-haul trips. Analysis of sensitivity of social welfare and profit gain as well as taxi/customer wait/search times is conducted with respect to the parameters in the nonlinear fare structure for the Hong Kong taxi market, and Pareto-improving nonlinear fare amendments are identified that neither disadvantage any customer nor reduce the taxi operators' profits. (C) 2010 Elsevier Ltd. All rights reserved.
On dynamic demand responsive transport services with degree of dynamism
(2014-01-02)
Wong, K. I.
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Han, A. F.
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Yuen, C. W.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
The operation of a demand responsive transport service usually considers advanced and real-time requests. Previous studies focused on solution algorithms for routing and scheduling challenges of a pickup and delivery problem with time windows, but the operational issues of the overall system performance under a partially dynamic environment have not been investigated. In this article, we explore the operating efficiency of a dispatching system with a degree of dynamism (i.e. a ratio of dynamic requests). It is found that a dispatching system incurs higher transportation costs and accepts fewer requests when the request arrivals are partially dynamic, as compared to static or fully dynamic scenarios. Operational policies are derived for the dispatcher to avoid the inefficient range of degree of dynamism if future demand can be anticipated.
ON THE PATH TOWARDS SUSTAINABLE TRANSPORTATION FOR GAMING-LED TOURISM CITY: THE CASE OF MACAO
(2010)
Wan, I. M.
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Wong, K. I.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
As one of the two special administrative regions of China, Macao is a gaming-led tourism city owing to its unique city profile. Macao has rich historic buildings and monuments, and the historic center was awarded `World Cultural Heritage\' by the United Nations Educational, Scientific and Cultural Organization in 2005. Since reunification with China in 1999, the Macao Government has defined gaming sector as their long term economic development direction and has deregulated the monopoly of the gaming industry in 2002. This strategy has successfully boosted the tourism as well as the economics in the city. However, the transportation system does not catch up with the increasing demand from both citizens and visitors, and the mobility of people within the city is of increasing concern. Notably, casinos and gaming groups provided their own transportation service - free shuttle services between selected locations - to compete between each other. This solves part of the transportation problem for visitors but also damages the accessibility of many local residents in various ways. Recently, the Government has announced the first ten-year land transport policy consultation paper for defining goals towards sustainable transportation development for the next decade. In this study, an overview of transportation system of Macao will be carried out through the assessment of urban development, land use and tourism. The impacts of city development and the possible directions for sustainable transportation of the city will be discussed. The unique experience for a tourism oriented city for developing transport sustainability will be critically examined.
Reliability-based stochastic transit assignment with capacity constraints: Formulation and solution method
(2013-10-01)
Szeto, W. Y.
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Jiang, Yu
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Wong, K. I.
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Solayappan, Muthu
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運輸與物流管理系註：原交通所+運管所
This paper proposes a Linear Complementarity Problem (LCP) formulation for the reliability-based stochastic transit assignment problem with capacity constraints and non-additive link costs, where in-vehicle travel times and waiting times are uncertain. The capacity constraints are developed via the notions of effective capacity and chance constraints. An equivalent route-based linear program (LP) for the proposed problem is formulated to determine the patronage of each line section, critical links, critical service frequencies, unmet demand and the network capacity, which considers the risk-aversive behavior of travelers. A solution method is developed, utilizing the IC-shortest path algorithm, the column generation technique, and the revised simplex method, to solve the proposed LP with guaranteed finite convergence. Numerical experiments are also set up to illustrate the properties of the problem and the application of the proposed model for reliability analysis. (C) 2011 Elsevier Ltd. All rights reserved.
Residents' perceptions on the traffic impact of a special event: a case of the Macau Grand Prix
(2018-01-01)
Han, Anthony F.
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Wong, K. I.
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Ho, S. N.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
Special events may cause significant disruptions to the community and affect the daily lives of the local residents. This study examines how local residents perceive the traffic impact of a major tourism event, the Macau Grand Prix, which is an annual event that takes place on a circuit around the streets of the city, Macao. An exploratory factor analysis reveals five factors regarding the traffic impacts of the event, and the residents of different transportation modes have distinct views on the traffic measures. Bus transit and pedestrian traffic management is found to be the most effective. The result provides the event organizer implications and assessment for the traffic planning and management measures in gaining support from the community.
SHORT-TERM TRAFFIC FLOW FORECASTING FOR URBAN ROADS
(2009)
Hsieh, Ya-Chen
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Wong, K. I.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
The interests and applications of short-term traffic forecasting have been growing in the recent years. Many of the applications in Advance Traveler Information System (ATIS) and Advance Traffic Management Systems (ATMS) require an estimation and forecasting of the traffic conditions of the network. With a historical database of past traffic data from various types of vehicle detectors installed in the roads, real-time traffic information is collected which will be used to estimate the current traffic conditions and predict the condition in near future. Whereas most of the literature focused on the traffic flow prediction on the freeways, modeling traffic flow in urban arterials is more challenging as there are disturbances such as motorcycles and traffic signals in urban area. In this study, the traffic flow forecasting for urban arterials is investigated. Seasonal ARIMA and neural network are considered as the algorithms, and two arterials in the Taipei city, Taiwan, are studied in our numerical example.
SHORT-TERM TRAFFIC FLOW FORECASTING FOR URBAN ROADS USING SPACE-TIME ARIMA
(2010)
Wong, K. I.
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Hsieh, Ya-Chen
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
With the development of technologies in telemetric, the interests and applications of Intelligent Transportation Systems (ITS) have been growing in the recent years. The applications in Advanced Traveler Information System (ATIS) and Advanced Traffic Management Aystem (ATMS) require the forecasting of traffic pattern to the near future. In contrast to the strategic models which predict over a period of month or year for long-term planning purposes, short-term models forecast traffic conditions within a day or a few hours that capture the dynamics of traffic, and are suitable for traffic management and information systems. A wide variety of short-term traffic forecasting problems have been investigated during past decades. An earlier comprehensive overview was given by Vlahogianni et al. (2004). Usage of input data would separate the forecasting techniques into univariate and multivariate approaches (Makridakis and Wheelwright, 1978). Univariate methods assumed that utilizing the historical time series data of a single variable is sufficient to detect the basic pattern for forecasting. Among the univariate models, autoregressive integrated moving average (ARIMA) model has been successfully applied in many areas and proved for its advantages over some other forecasting methods (Williams et al., 1998; Smith et al., 2002). Multivariate methods assumed there exists some relationships between two or more variables, and this pattern or trend can be extrapolated into the future (Stathopoulos and Karlaftis, 2003). This approach enables the modeling of the relationship of traffic measurements at different locations. The modelling of spatial-temporal domain of traffic data in urban area has been receiving attention in the recent years. Yang (2006) developed a spatial-temporal Kalman filter (STKF) forecasting model to compare with ARIMA and neural network (NN). An adaptive forecasting model selection strategy was proposed, which selects STKF with real-time data, but switch to use historical average method if real-time data was not available. Ghosh et al. (2009) proposed a structural time-series model methodology, which considers explicitly the trend, seasonal, cyclical, and calendar variations of traffic pattern, with the model flexibility that the immediate upstream junctions can be incorporated in the model as explanatory variables for the downstream predictions. In this paper, the space-time ARIMA (STARIMA) is used to investigate the spatial-temporal relationship and forecasting of urban traffic flow. Following the successful implements of ARIMA in the single location traffic prediction, a natural extension is to develop the multivariate version of the model with spatial-temporal domain. The space-time ARIMA model was firstly proposed by Pfeifer and Deutsch (1980), and is characterized by the autoregressive and moving average forms of several univariate time series lagged in both space and time. As compared to the ARIMA model, the calibrated model of STARIMA has the advantage with its small number of parameters, requiring fulfillment of rigorous statistical tests. A case study using the traffic data from 24 vehicle detectors in Taipei city, Taiwan are used to illustrate the performance of the model, and it is shown that STARIMA model are suitable for traffic flows forecasting in urban area.
Short-term Travel Time Estimation and Prediction for Long Freeway Corridor using NN and regression
(2012)
Wang, J. Y.
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Wong, K. I.
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Chen, Y. Y.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
Travel time information is a fundamental component in Advanced Traveler Information System. In this paper, we propose a short-term travel time estimation and prediction framework for long freeway corridor, considering measurements from vehicle detectors (VD) and floating car data (FCD). The modeling approach is based on a modified Nearest-Neighborhood (NN) model with threshold and a regression model capturing the within day variations. The advantages are that our approach allows for missing data without the need of data imputation in real-time, and is suitable for travel time prediction of long corridors. The validation analysis using an 88 km long section of freeway shows satisfactory results.
Special issue: Freight transport and sustainability
(2013-06-01)
Ganji, S. S.
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Wong, K. I.
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Najafi, Mohammad
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
STRATEGIES FOR THE DYNAMIC DIAL-A-RIDE PROBLEM
(2005)
Wong, K. I.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
In the Dial-a-Ride Problem (DARP), passengers specific their transportation requests between origins and destinations with desired departure or arrival time, and the operator is responsible to provide transportation with a fleet of vehicles. The objective of the scheduler is to design a set of routes which minimizes the total service cost, capable of providing service to all requests. Existing approaches on the DARP focus on the static version of the problem. The objective of this paper is to develop an efficient strategy for the dynamic dial-a-ride problem to describe how the operator should response to the requests and manage the vehicles, taking into account the real-time characteristics and stochastic effects. In contrast to the heuristics used in the static problems which emphasize in the routing component, we identify that the core of the strategy in the dynamic approach is in the scheduling component.
The optimal dispatching of taxis under congestion: a rolling horizon approach
(2006-03-01)
Wong, K. I.
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Bell, Michael G. H.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
Taxis make an important contribution to transport in many parts of the world, offering demand-responsive, door-to-door transport. In larger cities, taxis may be hailed on-street or taken from taxi ranks. Elsewhere, taxis are usually ordered by phone. The objective of a taxi dispatcher is to maximize the efficiency of fleet utilization. While the spatial and temporal distribution of taxi requests has in general a high degree of predictability, real time traffic congestion information can be collected and disseminated to taxis by communication technologies. The efficiency of taxi dispatching may be significantly improved through the anticipation of future requests and traffic conditions. A rolling horizon approach to the optimisation of taxi dispatching is formulated, which takes the stochastic and dynamic nature of the problem into account. Numerical experiments are presented to illustrate the performances of the heuristics, taking the time dependency of travel times and passenger arrivals into account.
WAITING STRATEGIES FOR THE DYNAMIC DIAL-A-RIDE PROBLEM
(2007)
Yuen, C. W.
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Wong, K. I.
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Han, Anthony F.
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management