K. Kulkarni, H.C. Lau, H. Wang, S. Sivabalasingam and K.T. Tran. Design and Implementation of Decision Support for Traffic Management at Multipurpose Port Gates. 2018 Winter Simulation Conference (WSC 2018), Gothenburg, Sweden, Dec 2018.
Effective traffic management can help port operators gain a competitive edge in service level and efficient use of limited resources. One critical aspect of traffic management is gate operations management, ensuring a good customer experience to logistic carriers and considering the impact of congestion in and around the port. In this paper, we describe the design and implementation of a decision support tool to help gate operators plan for future scenarios with fluctuating demand and limited resources. We propose a simulationoptimization framework which incorporates theoretical results from queuing theory to approximate complex multi-lane multi-server systems. Our major contribution in this paper is the demonstration that the proposed design, when coupled with real data, can indeed help port operators improve their performances. To provide concrete real-world evidence that such technology has benefits, we have tested the system operationally since December 2017 and present the results and analysis in this paper.
S. Shekhar Jha, S.-F. Cheng, R. Rajendram, N. Wong, F. B. A. Rahman, N. T. Trong, M. Lowalekar and P. Varakantham. A driver guidance system for taxis in Singapore, Seventeenth International Conference on Autonomous Agents and Multiagent Systems. 17th International Conference on Autonomous Agents and Multiagent Systems (AAMAS-18), Pg 1820-1822, Stockholm, Sweden, Jul 2018.
Traditional taxi fleet operators world-over have been facing intense competitions from various ride-hailing services such as Uber and Grab. Based on our studies on the taxi industry in Singapore, we see that the emergence of Uber and Grab in the ride-hailing market has greatly impacted the taxi industry: the average daily taxi ridership for the past two years has been falling continuously, by close to 20% in total. In this work, we discuss how efficient real-time data analytics and large-scale multiagent optimization technology could help taxi drivers compete against more technologically advanced service platforms. Our system has been in field trial with close to 400 drivers, and our initial results show that by following our recommendations, drivers on average save 21.5% on roaming time.
S.-F. Cheng, S. Shekhar Jha, R. Rajendram. Taxis strike back: A field trial of the driver guidance system. Seventeenth International Conference on Autonomous Agents and Multiagent Systems (AAMAS-18), to appear, Stockholm, Sweden, Jul 2018.
Traditional taxi fleet operators world-over have been facing intense competitions from various ride-hailing services such as Uber and Grab (specific to the Southeast Asia region). Based on our studies on the taxi industry in Singapore, we see that the emergence of Uber and Grab in the ride-hailing market has greatly impacted the taxi industry: the average daily taxi ridership for the past two years has been falling continuously, by close to 20% in total. In this work, we discuss how efficient real-time data analytics and large-scale multi-agent optimization technology could potentially help taxi drivers compete against more technologically advanced service platforms.
S. Shekhar Jha, S.-F. Cheng, M. Lowalekar, N. Wong, R. Rajendram, T.K. Tran, P. Varakantham, N.T. Trong, F.B.A. Rahman. Upping the Game of Taxi Driving in the Age of Uber. Thirtieth Annual Conference on Innovative Applications of Artificial Intelligence (IAAI-18), New Orleans, USA, Feb 2018
In most cities, taxis play an important role in providing point-to-point transportation service. If the taxi service is reliable,responsive, and cost-effective, past studies show that taxi-like services can be a viable choice in replacing a significant amount of private cars. However, making taxi services efficient is extremely challenging, mainly due to the fact that taxi drivers are self-interested and they operate with only local information. Although past research has demonstrated how recommendation systems could potentially help taxi drivers in improving their performance, most of these efforts are not feasible in practice. This is mostly due to the lack of both the comprehensive data coverage and an efficient recommendation engine that can scale to tens of thousands of drivers.
L. Agussurja, K. Akshat and H. C. Lau. Resource-Constrained Scheduling for Maritime Traffic Management. In Proc. Thirty-Second AAAI Conference on Artificial Intelligence (AAAI-18), New Orleans, USA, Feb 2018.
We address the problem of mitigating congestion and preventing hotspots in busy water areas such as Singapore Straits and port waters. Increasing maritime traffic coupled with narrow waterways makes vessel schedule coordination for just-in-time arrival critical for navigational safety. Our contributions are: 1) We formulate the maritime traffic management problem based on the real case study of Singapore waters; 2) We model the problem as a variant of the resourceconstrained project scheduling problem (RCPSP), and formulate mixed-integer and constraint programming (MIP/CP) formulations; 3) To improve the scalability, we develop a combinatorial Benders (CB) approach that is significantly more effective than standard MIP and CP formulations. We also develop symmetry breaking constraints and optimality cuts that further enhance the CB approach’s effectiveness; 4) We develop a realistic maritime traffic simulator using electronic navigation charts of Singapore Straits. Our scheduling approach on synthetic problems and a real 55-day AIS dataset results in significant reduction of the traffic density while incurring minimal delays.
B.X. Li, H. Wang , H.C. Lau. An Exact Approach for the Vehicle Routing Problem with Location Congestion. 6th INFORMS Transportation Science and Logistics Society Workshop (TSL 2018), Hong Kong, Jan 2018
The Vehicle Routing Problem with Location Congestion (VRPLC) integrates Vehicle Routing Problem (VRP) and the location congestion constraints (e.g., due to docking capacity). The capacity of any location that needs to be served by multiple vehicles is assumed to be limited, so that only a limited number of vehicles can visit a location in any particular time period. The goal for VRPLC is to minimize the weighted summation of vehicle travel time between visited locations and vehicle waiting time induced by the visited locations congestion. We formulate the problem into a Mixed Integer Programming (MIP) model and propose an exact approach using Benders decomposition to solve it.
L. Lin, C.K. Han, S.-F. Cheng, H. C. Lau, and A. Misra. Smart Bundling for Crowdsourced Package Deliveries. 6th INFORMS Transportation Science and Logistics Society Workshop (TSL 2018), Hong Kong, Jan 2018
Mobile crowdsourcing, which involves the use of a pool of crowd-workers who visit different locations to perform a variety of location-specific tasks, has emerged as a key paradigm for executing many urban services. While on-demand crowdsourced transportation (e.g. Uber) has arguably received the greatest attention, last mile logistics and package delivery is another service that is rapidly adopting this crowdsourcing paradigm. Crowdsourced package delivery has several key advantages: (1) Logistics companies no longer have to maintain a large dedicated fleet and worker pool, thus reducing their capital expenses; (2) They can tap on a flexible workforce that can handle seasonal demand fluctuations. Despite avid interests in adopting the crowdsourcing paradigm, most current practices suffer from the inefficiency caused by decentralized task allocation. This is so since crowd-workers need to independently browse and choose their preferred tasks, which in most cases are cognitively demanding and rarely optimal.
Last updated on 24 Aug 2018 .