Wyniki wyszukiwania - BazTech

1

Forecast duration of requests with time constraints in the dynamic vehicle routing problem

Fedczuk S.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2017

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z. 75

17--18

EN

This paper presents a simple algorithm used to forecast realization time of requests. It takes into account priorities of requests and maximum efficiency of deliveries with limited resources. The method is based on predicting future states based on hypothetical requests in some fixed time horizon. The efficiency of the algorithm has been verified by two simulations.

2

Online taxi dispatching via exact offline optimization

Maciejewski M.

Logistyka

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2014

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nr 4

EN

The paper proposes an online taxi dispatching strategy that is based on solving exactly the equivalent offline problem at each decision epoch. First, a general framework for simulating dynamic transport services in MATSim (Multi-Agent Transport Simulation) is described. Next, the model of online taxi dispatching is defined, followed by a formulation of the offline problem as a mixed integer programming problem. Then the MIP strategy that solves the offline problem with a finite planning horizon at each decision epoch is described. The performance of MIP was evaluated on the simulation scenario of taxi services in the city of Mielec and compared with that of two selected strategies (RES and NOS). The obtained results show the advantage of MIP over the reference strategies in terms of the solution quality, but at the cost of response time.

PL

W artykule zaproponowano strategię przydziału online taksówek do zleceń opartą na dokładnym rozwiązaniu odpowiednika problemu w trybie offline dla każdej epoki decyzyjnej. W pierwszej kolejności opisano ogólny szkielet symulacji dynamicznych usług transportowych w MATSim (Multi-Agent Transport Simulation). Następnie zdefiniowano model przydziału taksówek do zleceń w trybie online oraz sformułowano problem offline jako problem programowania mieszanego całkowitoliczbowego MIP. W oparciu o ten problem stworzono strategię MIP polegającą na rozwiązywaniu problemu offline dla skończonego horyzontu planistycznego dla każdej epoki decyzyjnej. Efektywność strategii MIP oceniono na podstawie scenariusza symulacyjnego usług taksówkowych w Mielcu i porównano z efektywnością dwóch wybranych strategii (RES i NOS). Otrzymane rezultaty wskazują na przewagę MIP nad strategiami referencyjnymi pod względem jakości rozwiązań, ale kosztem czasu odpowiedzi.

3

Benchmarking minimum passenger waiting time in online taxi dispatching with exact offline optimization methods

Maciejewski M.

Archives of Transport

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2014

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Vol. 30, iss. 2

67--75

EN

This paper analyses the use of exact offline optimization methods for benchmarking online taxi dispatching strategies where the objective is to minimize the total passenger waiting time. First, a general framework for simulating dynamic transport services in MATSim (Multi-Agent Transport Simulation) is described. Next, the model of online taxi dispatching is defined, followed by a formulation of the offline problem as a mixed integer programming problem. Three benchmarks based on the offline problem are presented and compared to two simple heuristic strategies and a hypothetical simulation with teleportation of idle taxis. The benchmarks are evaluated and compared using the simulation scenario of taxi services in the city of Mielec. The obtained (approximate) lower and upper bounds for the minimum total passenger waiting time indicate directions for further research.