Contributed Session Mon.3.H 0106

Monday, 15:15 - 16:45 h, Room: H 0106

Cluster 13: Logistics, traffic, and transportation [...]

Applications in transportation problems


Chair: Paola Pellegrini



Monday, 15:15 - 15:40 h, Room: H 0106, Talk 1

Joshua Adekunle Magbagbeola
Operations research approach to enhancing enterprise through alliances: A case study of Mowe Town, Ogun State, Nigeria

Coauthors: Samuel A. Awoniyi, Eunice O. Magbagbeola


Small firm sub-sector has the potential to reduce poverty and unemployment in Nigeria. However, in the face of global competition, market uncertainties and rapid technological changes, it is necessary to assist firms, particularly small enterprise to access information that can build their business competencies to create income and employment generation opportunities. Through in-depth recourse to existing theories and empirical literature on factors that explain firm growth, the study identifies business competencies, derived through inter-firm alliances, as determinants of enterprise performance. The study establishes that the size of the firm influences the choice of business association among manufacturing enterprises in Nigeria. It is further noted that the decision to join a business association is positively related to the ages of the entrepreneur and enterprise. The study recommends incentive mechanisms that encourage business associations among small enterprise.



Monday, 15:45 - 16:10 h, Room: H 0106, Talk 2

Hidetoshi Miura
Comparative study of reduced total travel times in check-pattern and hierarchical express systems

Coauthor: Toshio Nemoto


Express-service stop pattern on railway is an important factor to shorten travel time for long-distance users. However, it is difficult for trunk line to run enough expresses during rush hours by reason of track capacity for safety. Lack of track capacity gives trains few occasions to pass others. This study calculates reduced total travel time by expresses to compare three limited-service stop patterns: single express pattern system, check-pattern system, and hierarchical system. The hierarchical system gives stops of upper type of express to include all stops of lower expresses. The check-pattern system does not allow sharing stops between different types of expresses. Though the check-pattern system does not become common, it will give more expresses than the hierarchical system during high train density. Some simple assumptions in this railway model facilitate analytical representation to locate limited-service stops for maximizing reduced travel times. We will describe the optimal limited-service stop patterns and the optimal number of stops of three systems.



Monday, 16:15 - 16:40 h, Room: H 0106, Talk 3

Paola Pellegrini
Exact models for the real time railway traffic management problem: tackling perturbed traffic considering real junction details

Coauthors: Grégory Marlière, Joaquin Rodriguez


A railway traffic management problem appear when trains are delayed: the originally planned routing and scheduling become infeasible. This problem must be solved in real time (i.e., in a short time) by finding a minimum cost feasible routing and scheduling of trains on a network. Solution cost is assessed in terms of either punctuality or fluidification.
In the literature, this problem, known as "real time railway traffic management problem'', is typically tackled with heuristic algorithms. Optimal approaches appear only when few network details are considered. We propose two mixed-integer linear programming models which consider real railway junctions details. They differ in the computation of solution cost.
We test the two models on real instances representing three complex junctions: Pierrefitte-Gonesse (France), Lille Flandres station (France), and Utrecht Den Bosh line (Netherlands).
In all cases, computation time is very short. Interestingly, different junctions are differently complex for the two models. We will devote further research to the explanation of these differences, and to the identification of effective valid inequalities.


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