Computer science

Skill mismatch is worldwide issue as it can be effect job satisfaction, wages and multiple other factors. Analyzing selft-reported skill mismatch is highly studied in prior work. In this paper we study evidence of skill mismatch between three categories: Professionals, Students and Faculty member. We collect data from a survey. In this paper we use the Chi-Test to find evidence of skill mismatch between Professionals, Faculty members and students. We suppose that the three proportions are equals which means they agree on the importance of skills. If the hypothesis in not true we use the Marascuillo procedure to make comparisons between all pairs of groups Results of our paper shows that categories agree on the importance of skills categories especially programming languages; However, we find evidence of a mismatch between skills types especially Databases and Audit and risk analysis. We also find agreement between groups for some skills such as C++, as participants agree that this skill is not highly used in the cybersecurity job market.

Data science techniques are powerful tools for extracting knowledge from large datasets. Analyzing the job market by classifying online job advertisements (ads) has recently received much attention. Various approaches for multi-label classification (e.g., self-supervised learning and clustering) have been developed to identify the occupation from a job advertisement and have achieved a satisfying performance. However, these approaches require labeled datasets with hundreds of thousands of examples and focus on specific databases such as the Occupational Information Network (O*NET) that are more adapted to the US job market. In this paper, we present a two-stage job title identification methodology to address the case of small datasets. We use Bidirectional Encoder Representations from Transformers (BERT) to first classify the job ads according to their corresponding sector (e.g., Information Technology, Agriculture). Then, we use unsupervised machine learning algorithms and some similarity measures to find the closest matching job title from the list of occupations within the predicted sector. We also propose a novel document embedding strategy to address the issues of processing and classifying job ads. Our experimental results show that the proposed two-stage approach improves the job title identification accuracy by 14% to achieve more than 85% in some sectors. Moreover, we found that incorporating document embedding-based approaches such as weighting strategies and noise removal improves the classification accuracy by 23.5% compared to approaches based on the Bag of words model. Further evaluations verify that the proposed methodology either outperforms or performs at least as well as the state-of-the-art methods. Applying the proposed methodology to Moroccan job market data has helped identify emerging and high-demand occupations in Morocco.

This paper proposes a simulation model to analyze the handling and the transfer system of containers in Le Havre seaport. The decision variables of simulation are determined by using the CPLEX optimization software. The goal is to determine the least expensive strategy for the transfer of a set of containers between container terminals. The simulation model is developed using an object-oriented approach and Flexsim CT simulation software. The objective is to obtain an efficient operating process for the multimodal terminal of Le Havre which is an intermediate platform for transferring containers (collection and delivery) by rail and river (trains and barges). The goal is to evaluate the performance of the containers transfer by rail shuttles between the future multimodal terminal and the maritime terminals. The aim is to analyze and to evaluate performance indicators of port logistics chain (costs, resource occupancy rate, service rate), and to test several management strategies.

The exponential flow of goods and passengers growth, fragility of certain products and the need for the optimization of transport costs imposed on carriers to use more and more multimodal transportation. In addition, the need for intermodal transport policy has been strongly driven by environmental concerns and to benefit from the combination of different modes of transport to cope with growing flows of goods. In this paper, we propose an optimization model of intermodal transport of cut flowers from the real world. We formulate the problem as a bi-objective mathematical program with binary variables, discuss the assumptions of formulation and apply the method of weighted sum for the problem. Finally, we give some experimental results found by the method of Branch and Cut of Cplex for instances related to the case studied.

The exponential growth of the flow of goods and passengers, fragility of certain products and the need for the optimization of transport costs impose on carriers to use more and more multimodal transport. In addition, the need for intermodal transport policy has been strongly driven by environmental concerns and to benefit from the combination of different modes of transport to cope with the increased economic competition.This research is mainly concerned with the Intermodal Terminal Location Problem introduced recently in scientific literature which consists to determine a set of potential sites to open and how to route requests to a set of customers through the network while minimizing the total cost of transportation. We begin by presenting a description of the problem. Then, we present a mathematical formulation of the problem and discuss the sense of its constraints. The objective function to minimize is the sum of road costs and railroad combined transportation costs.As the pr...

RESUME : L'objectif de ce travail est de proposer un mode d'exploitation optimisé, basé sur une approche d'optimisation et de simulation, pour le transfert ferroviaire massifié de conteneurs entre le terminal maritime Atlantique et le futur terminal multimodal du port du Havre. L'outil de simulation à événements discrets a été réalisé en utilisant le logiciel Flexsim CT. Les variables de décision de la simulation sont déterminées par l'optimisation grâce au logiciel Cplex. Le but est de déterminer la stratégie la moins coûteuse pour le transfert d'un ensemble de conteneurs entre deux terminaux à conteneurs. Des résultats numériques sont présentés et analysés pour montrer l'efficacité de notre approche.

Le Havre Port Authority is putting into service a multimodal hub terminal with massified hinterland links (trains and barges) in order to restrict the intensive use of roads, to achieve a more attractive massification share of hinterland transportation and to provide a river connection to its maritime terminals that do not currently have one. This paper focuses on the rail-rail transshipment yard of this new terminal. In the current organizational policy, this yard is divided into two equal operating areas, and, in each one, a crane is placed, and it is equipped with reach stackers to enable container moves across both operating areas. However, this policy causes poor scheduling of crane moves, because it gives rise to many crane interference situations. For the sake of minimizing the occurrence of these undesirable situations, this paper proposes a multi-agent simulation model including an improved strategy for crane scheduling. This strategy is inspired by the ant colony approach and it is governed by a new configuration for the rail yard's working area that eliminates the use of reach stackers. The proposed simulation model is based on two planner agents, to each of which a time-horizon planning is assigned. The simulation results show that the model developed here is very successful in significantly reducing unproductive times and moves (undesirable situations), and it outperforms other existing simulation models based on the current organizational policy.

In this paper, we introduce and study the incomplete version of the intermodal terminal location problem. It's a generalization of the classical version by relaxing the assumption that the induced graph by located terminals is complete. We propose a mixed integer program to model the problem and we provide several extensions. All models are tested through validation in CPLEX solver. Numerical results are reported using well-known data set from the literature.

This chapter addresses different optimization/simulation approaches for the innovative logistics in Le Havre port in France. These approaches are applied to various decisional problems raised in the maritime terminals (MT) and in the multimodal terminal (MMT). The first problem concerns container transfer by rail between the maritime terminals and the multimodal terminal. The second aims to optimize trains/shuttles parking in the rail yard of the multimodal terminal. The third and the fourth are about rail-rail transshipment of containers. The goal is to elaborate a dashboard for decision makers to analyze and evaluate performance indicators of port logistics chain (costs, resource occupancy rate, service rate) and to test several management strategies.

A parallel genetic algorithm (GA) implemented on GPU clusters is proposed to solve the Uncapacitated Single Allocation p-Hub Median problem. The GA uses binary and integer encoding and genetic operators adapted to this problem. Our GA is improved by generated initial solution with hubs located at middle nodes. The obtained experimental results are compared with the best known solutions on all benchmarks on instances up to 1000 nodes. Furthermore, we solve our own randomly generated instances up to 6000 nodes. Our approach outperforms most well-known heuristics in terms of solution quality and time execution and it allows hitherto unsolved problems to be solved.

Nowadays, seaports seek to achieve a better massification (massive transportation of containers) share of their hinterland transport by promoting rail and river connections in order to more rapidly evacuate increasing container traffic shipped by sea and to avoid landside congestion. The attractiveness of a seaport to shipping enterprises depends not only on its reliability and nautical qualities but also on its massified hinterland connection capacity. Contrary to what has been observed in Europe, the massification share of Le Havre seaport has stagnated in recent years. To overcome this situation, Le Havre Port Authority is putting into service a multimodal hub terminal linked only with massified modes. In this study, we focus on rail–rail transshipment of this new terminal, specifically on minimizing unproductive situations of cranes to improve crane productivity and to speed up freight train processing. To this end, an improving agent-based engineering strategy called the “crane...

Growing competition in the world enforces the need for an efficient design of transportation networks. Furthermore, a competitive transportation network should also be eco-friendly. As road transportation is responsible for the largest quantities of CO2 emissions, Intermodal Transportation (IT) might be a potential alternative. From this perspective, intermodal terminals location is a cornerstone for building a sustainable transportation network. The purpose of this paper is to study and efficiently solve the Intermodal Terminal Location Problem on incomplete networks. We model this problem as a mixed integer linear program and develop a simulated annealing algorithm to tackle medium and large instances. The computational results show that the obtained solutions using simulated annealing are competitive and close to the exact solutions found by CPLEX solver for small and medium instances. The same developed algorithm outperforms the best found solutions from the literature using heu...

High transportation costs and poor quality of service are common vulnerabilities in various logistics networks, especially in food distribution. Here we propose a many-objective Customer-centric Perishable Food Distribution Problem that focuses on the cost, the quality of the product, and the service level improvement by considering not only time windows but also the customers’ target time and their priority. Recognizing the difficulty of solving such model, we propose a General Variable Neighborhood Search (GVNS) metaheuristic based approach that allows to efficiently solve a subproblem while allowing us to obtain a set of solutions. These solutions are evaluated over some non-optimized criteria and then ranked using an a posteriori approach that requires minimal information about decision maker preferences. The computational results show (a) GVNS achieved same quality solutions as an exact solver (CPLEX) in the subproblem; (b) GVNS can generate a wide number of candidate solutions...

Freight transport is essential to modern urban civilization. No urban area could exist without a powerful freight transport system. However, the distribution of perishable foods in urban areas is seen as a source of problems, due to traffic congestion, time pressures, and environmental impact. In this paper, an Agent-Based Model integrated with Geographic Information Systems (ABM-GIS) is designed for a time-dependent vehicle routing problem with time windows. This simulation model consists of determining the quickest routes to transport fresh products, estimating Vehicle kilometer traveled VKT and vehicle hour traveled VHT where speeds and travel times depend on the time of the day. Based on a case study, analyses of changes on traffic condition were conducted to get an insight into the impact of these changes on cost, service quality represented by the respect of time windows, and carbon emissions. The results reveal that traffic jams and restrictive time windows lead to additional cost, cause delays, and increase co2 emission. As for a short-term planning, time-dependent scheduling algorithm was proposed and assessed while extending time windows. Results have proved the potential saving in cost, travel time, and carbon emission. 2 Agent Based Model and GIS integration Agent-based modeling is a relatively new method compared to system dynamics and discrete event modeling. This modeling paradigm is developed to simulate complex systems through the study of active entities behavior, known as agents. Agent Based System (ABS) has been adopted to solve complex problems, from various domains, such as logistics optimization, traffic, and urban planning. ABS can be used for different purpose: (1) Understanding observed dynamics, processes, and systems, (2) Designing or engineering of processes or systems, (3) Managing a system or process,(4) Formulating theory and explanatory

L’objectif de ce travail est de proposer un mode d’exploitation optimise, base sur une approche d’optimisation et de simulation, pour le transfert ferroviaire massifie de conteneurs entre le terminal maritime Atlantique et le futur terminal multimodal du port du Havre. L’outil de simulation a evenements discrets a ete realise en utilisant le logiciel Flexsim CT. Les variables de decision de la simulation sont determinees par l’optimisation grâce au logiciel Cplex. Le but est de determiner la strategie la moins couteuse pour le transfert d’un ensemble de conteneurs entre deux terminaux a conteneurs. Des resultats numeriques sont presentes et analyses pour montrer l’efficacite de notre approche.

le cadre du projet DCAS pour ses remarques, relectures et suggestions. Je remercie Michèl Bézien, photographe au GPMH, pour la collection de photos fournie et pour ses nombreuses conseils et remarques. Un grand merci pour mes collègues au laboratoire Modélisation et Calcul Scientifique de la FST de Fès, au laboratoire du Mathématiques Appliquées du Havre et à la Direction des Transports Terrestres au GPMH. Je remercie chaleureusement mes parents, mes soeurs et frères pour leur encouragement permanent et pour l'intérêt qu'ils ont toujours porté pour ce que je faisais. Je remercie bien tendrement ma femme pour ses encouragements et pour son soutien inconditionnel. Je remercie tous les membres de ma famille, mes amis, collègues et professeurs pour leur soutien inestimable. vi 4 Modélisation des problèmes d'optimisations rencontrés .