Scheduling on Hybrid Platforms: Improved Approximability Window

Modern platforms are using accelerators in conjunction with standard processing units in order to reduce the running time of specific operations, such as matrix operations, and improve their performance. Scheduling on such hybrid platforms is a challenging problem since the algorithms used for the case of homogeneous resources do not adapt well. In this paper we consider the problem of scheduling a set of tasks subject to precedence constraints on hybrid platforms, composed of two types of processing units. We propose a $(3+2\sqrt{2})$-approximation algorithm and a conditional lower bound of 3 on the approximation ratio. These results improve upon the 6-approximation algorithm proposed by Kedad-Sidhoum et al. as well as the lower bound of 2 due to Svensson for identical machines. Our algorithm is inspired by the former one and distinguishes the allocation and the scheduling phases. However, we propose a different allocation procedure which, although is less efficient for the allocation sub-problem, leads to an improved approximation ratio for the whole scheduling problem. This approximation ratio actually decreases when the number of processing units of each type is close and matches the conditional lower bound when they are equal

Branch-and-bound algorithm for total weighted tardiness minimization on parallel machines under release dates assumptions

This paper deals with the parallel-machine scheduling problem with the aim of minimizing the total (weighted) tardiness under the assumption of different release dates. This problem has been proven to be NP-hard. We introduce some new lower and upper bounds based on different approaches. We propose a branch-and-bound algorithm to solve the weighted and unweighted total tardiness. Computational experiments were performed on a large set of instances and the obtained results showed that our algorithms are efficient

No-wait scheduling of a two-machine flow-shop to minimize the makespan under non-availability constraints and different release dates

International audienceIn this paper, we consider the two-machine no-wait flow-shop scheduling problem, when every machine is subject to one non-availability constraint and jobs have different release dates. The non-availability intervals of the machines overlap and they are known in advance. We aim to find a non-resumable schedule that minimises the makespan. We propose several lower bounds and upper bounds. These bounding procedures are used in a branch-and-bound algorithm. Computational experiments are carried out on a large set of instances and the obtained results show the effectiveness of our method

Desarrollo de un componente Web parametrizable para la visualización de datos científicos

Auxiliar de InvestigaciónEste proyecto se fundamentó en el desarrollo de un componente Web parametrizable para la visualización de datos científicos, el cual permitirá a futuro, con integración de otros componentes, establecer un análisis visual de los datos extraídos, enfocado en la necesidad del usuario.1. GENERALIDADES 2. OBJETIVOS DEL PROYECTO 3. MARCO DE REFERENCIA 4. MARCO CONCEPTUAL 5. METODOLOGÍA 6. DESARROLLO DEL PROYECTO 7. RESULTADOS 8. CONCLUSIONES 9. TRABAJOS FUTUROS 10. BIBLIOGRAFÍA 11. GLOSARIO 12. ANEXOSPregradoIngeniero de Sistema