121 resultados para Chance constrained programming


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Microsoft Project is one of the most-widely used software packages for project management. For the scheduling of resource-constrained projects, the package applies a priority-based procedure using a specific schedule-generation scheme. This procedure performs relatively poorly when compared against other software packages or state-of-the-art methods for resource-constrained project scheduling. In Microsoft Project 2010, it is possible to work with schedules that are infeasible with respect to the precedence or the resource constraints. We propose a novel schedule-generation scheme that makes use of this possibility. Under this scheme, the project tasks are scheduled sequentially while taking into account all temporal and resource constraints that a user can define within Microsoft Project. The scheme can be implemented as a priority-rule based heuristic procedure. Our computational results for two real-world construction projects indicate that this procedure outperforms the built-in procedure of Microsoft Project

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mountains are among the regions most affected by climate change. The implications of climate change will reach far beyond mountain areas, as the contributions in the present publication prepared for the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 20) in Lima 2014 show. Themes discussed are water, glaciers and permafrost, hazards, biodiversity, food security and economy. The case studies included show that concrete adaptive action has been taken in many mountain areas of the world. The publication concludes with a series of recommendations for sustainable mountain development in the face of climate change.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper deals with “The Enchanted Journey,” which is a daily event tour booked by Bollywood-film fans. During the tour, the participants visit original sites of famous Bollywood films at various locations in Switzerland; moreover, the tour includes stops for lunch and shopping. Each day, up to five buses operate the tour. For operational reasons, however, two or more buses cannot stay at the same location simultaneously. Further operative constraints include time windows for all activities and precedence constraints between some activities. The planning problem is how to compute a feasible schedule for each bus. We implement a two-step hierarchical approach. In the first step, we minimize the total waiting time; in the second step, we minimize the total travel time of all buses. We present a basic formulation of this problem as a mixed-integer linear program. We enhance this basic formulation by symmetry-breaking constraints, which reduces the search space without loss of generality. We report on computational results obtained with the Gurobi Solver. Our numerical results show that all relevant problem instances can be solved using the basic formulation within reasonable CPU time, and that the symmetry-breaking constraints reduce that CPU time considerably.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Chance events are considered important in career development, yet little empirical research is available on their predictors and consequences. The present study investigated socio-demographic (gender, nationality, school-type), personality (openness, locus of control) and career development variables (career decidedness, career planning) in relation to perceived chance events with a retrospective (N = 229, eleventh grade), and 1-year longitudinal prospective study (N = 245, eighth/ninth grade) among Swiss adolescents. The results showed that the majority of both groups reported a significant influence of chance events on their transition from compulsory school to vocational education or high school. Importance of chance events related to socio-demographics and personality but not career preparation. Career preparation and chance events predicted subjective career success in terms of wish correspondence and overall satisfaction with transition outcome among the younger cohort. Implications include the necessity to integrate both thorough career preparation and chance events in theory and counseling practice.