Mixing Static and Dynamic Partitioning to Parallelize a Constraint Programming Solver

This paper presents an external parallelization of Constraint Programming (CP) search tree mixing both static and dynamic partitioning. The principle of the parallelization is to partition the CP search tree into a set of sub-trees, then assign each sub-tree to one computing core in order to perform a local search using a sequential CP solver. In this context, static partitioning consists of decomposing the CP variables domains in order to split the CP search tree into a set of disjoint sub-trees to assign them to the cores. This strategy performs well without adding an extra cost to the parallel search, but the problem is the load imbalance between computing cores. On the other hand, dynamic partitioning is based on preservation of the search state to generate, dynamically or on demand, the sub-trees that are assigned to the cores. This strategy offers good load balancing between the different computing cores, but computing overcosts appear due to the initialisation of the search when a sub-tree is migrated from one core to another. In this paper, we propose a new partitioning strategy that mixes the static and dynamic partitioning and enjoys the benefits of each strategy. This mixed partitioning is designed to run on shared and distributed memory architectures. The performances obtained are illustrated by solving the CP problems modelled using the FlatZinc format and solved using the Google OR-Tools solver on top of the parallel Bobpp framework.     

Numerical modelling for simulation and treatment planning of prostate thermal therapy

A 2D transmission line matrix model is used to study thermal transfer in living tissues exposed to laser energy. Damage size because of thermal coagulation in thermal treatment of benign prostate hyperplasia is determined quantitatively. Results show a quasilinear dependency of blood perfusion on temperature at the beginning of coagulation. Immediately thereafter, blood perfusion decreases considerably until it shuts down when the tissue under investigation has been coagulated. Increase in perfusion rate (ω) leads to high values of t₁₀₀, which is the time required to reach a primary zone temperature of about 100 °C, and reflects the increased cooling created by perfusion. The transmission line matrix numerical model predicts the coagulation damage contours; that way, it has a clinical interest in therapy as an aid for clinicians because damage cannot be easily measured within patients. Results are validated through comparison with other researches. Copyright © 2014 John Wiley & Sons, Ltd.     

KCSS: Kubernetes container scheduling strategy

The Journal of Supercomputing - The Kubernetes framework is a well-known open-source container-orchestration system widely used in industrial and academic fields. In this paper, we introduce a new...     

Opportunistic scheduling and resources consolidation system based on a new economic model

The Journal of Supercomputing - This paper presents a new opportunistic scheduling and resource consolidation system based on an economic model related to different service level agreements (SLAs)...     

Investigation of a Near-Perfect Quad-Band Polarization-Insensitive Metamaterial Absorber Based on Dual-T Circular Shaped Resonator Array Designed on a Silicon Substrate for C-, X- and Ku-bands Applications

Silicon - Multi-band metamaterial absorbers (MMAs) are increasingly becoming main devices for many electrical systems. Optimizing the electromagnetic qualities of this type of absorber in the...