Monia Rekik

An exact solution approach for multi-objective location-transportation problem for disaster response

This paper considers a three-objective location-transportation problem for disaster response. The location problem aims at determining the number, the position and the mission of required humanitarian aid distribution centers (HADC) within the disaster region. The transportation problem deals with the distribution of aid from HADCs to demand points. Three conflicting objectives are considered. The first objective minimizes the total transportation duration of needed products from the distribution centers to the demand points. The second objective minimizes the number of agents (first-aiders) needed to open and operate the selected distribution centers. The third objective minimizes the non-covered demand for all demand points within the affected area. We propose an epsilon-constraint method for this problem and prove that it generates the exact Pareto front. The proposed algorithm can be applied to any three-objective optimization problem provided that the problem involves at least two integer and conflicting objectives. The results obtained in our experimental study show that the computing time required by the proposed method may be large for some instances. A heuristic version of our algorithm yielded, however, good approximation of the Pareto front in relatively short computing times.

Solving multi-activity multi-day shift scheduling problems with a hybrid heuristic

This paper addresses a multi-activity multi-day shift scheduling problem in a continuous and flexible environment including a heterogeneous workforce. Given days-off schedules associated with each employee, our objective is to construct and assign admissible multi-activity shifts to employees on their work days in a way that minimizes under-staffing and over-staffing with a restricted budget on workforce cost. A hybrid heuristic which combines tabu search with a branch-and-bound procedure is proposed to solve the problem. The computational experiments prove that our method provides good schedules in relatively short computing times.

Reputation-based winner determination problem for combinatorial transportation procurement auctions

This paper proposes a reputation-based winner determination problem for transportation procurement auctions where the allocation of long-term contracts to carriers is decided with respect to both bid ask-prices and carriers reputation. The objective is to manage the trade-off between transport costs and the quality of service during operations. Carriers reputation is translated into unexpected hidden cost that represents the possible additional cost that the shipper may incur when dealing with a set of winning carriers. This cost depends essentially on the carriers reputation as evaluated by the shipper running the auction. To evaluate carriers reputations, the shipper uses a number of service attributes with different weights depending on shipping contracts.

A Decision Support System for Humanitarian Network Design and Distribution Operations

In this paper, we model the situation faced by decision-makers in the first hours following a disaster when they have to deploy a humanitarian aid distribution network. This is done by first determining the number and the choice of depots to be opened and then by planning the distribution of humanitarian aid from these depots towards the affected people. We propose a decision support system (DSS) to help decision-makers in these tasks. The DSS is built around mathematical models that provide answers to the network design and distribution problems, and is completed by a multi-criteria analysis module. The DSS also provides a complete interface to display the problem’s geographic structure, including distribution routes and the location of network nodes.

Transforming city initiative into a smart city initiative: the case of "winter maintenance operations"

A smart city has the objective to improve the quality of life of citizens by the extensive use of Information and Communication Technologies. In this project, the focus will be made on winter maintenance operations (WMO). Based on an integrative framework for smart cities initiatives, we will try to understand the links that can be established between smart city theoretical concepts and winter maintenance smart initiatives in practice. This proposal is a first step to bridge the gap between theory and practice by analysing smart city initiatives related to snow collecting. A qualitative analysis, based on structured observations and interviews with decision-makers of WMO in snowy cities, will be made in order to provide relevant knowledge that would serve as a basis for decision-makers to better plan their smart city initiatives.