Search results for "Algorithm"

Distributed multi-objective optimization methods for shape design using evolutionary algorithms and game strategies

2012

Rapid growth of Atlantic salmon juveniles in captivity may indicate poor performance in nature

2011

Abstract The hatchery environment often favours completely different traits than natural selection in the wild. Consequently, hatchery-reared fish are usually larger and more aggressive than their wild counterparts. Increased growth rate and aggression are predicted to be beneficial in feeding competition in hatcheries, but not necessarily in nature, where food resources are spatially and temporally more variable. We compared the growth, condition and mortality of landlocked Atlantic salmon (Salmo salar L.) juveniles in a common hatchery environment and when feeding on natural prey in semi-natural channels. We found that the growth and survival probability of the fish in the hatchery was ne…

Selecting networks of nature reserves: methods do affect the long-term outcome

1999

Data on vascular plants of boreal lakes in Finland were used to compare the efficiency of reserve selection methods in representing four aspects of biodiversity over a 63 year period. These aspects included species richness, phylogenetic diversity, restricted range diversity and threatened species. Our results show that the efficiency of reserve selection methods depends on the selection criteria used and on the aspect of biodiversity under consideration. Heuristic methods and optimizing algorithms were nearly equally efficient in selecting lake networks over a small geographical range. In addition, a scoring procedure was observed to be efficient in maintaining different aspects of biodive…

A Smoothed Particle Image Reconstruction method

2010

Many image processing techniques work with scattered data distribution usually employing grid based methods leading to numerical problems. To address this issue, a numerical method avoiding mesh generation can be used. Such a method performs an integral representation by means of a smoothing kernel function and, in the discrete formulation, involves domain particles. In this paper the meshless Smoothed Particle Hydrodynamics method is proposed in the Image Reconstruction context and a new computational strategy called Smoothed Particle Image Reconstruction is presented; the new method is based on a scatter approach and several innovative ideas are introduced in order to improve the computat…

Complexity of operations on cofinite languages

2010

International audience; We study the worst case complexity of regular operation on cofinite languages (i.e., languages whose complement is finite) and provide algorithms to compute efficiently the resulting minimal automata.

Imaginary time propagation code for large-scale two-dimensional eigenvalue problems in magnetic fields

2013

We present a code for solving the single-particle, time-independent Schr\"odinger equation in two dimensions. Our program utilizes the imaginary time propagation (ITP) algorithm, and it includes the most recent developments in the ITP method: the arbitrary order operator factorization and the exact inclusion of a (possibly very strong) magnetic field. Our program is able to solve thousands of eigenstates of a two-dimensional quantum system in reasonable time with commonly available hardware. The main motivation behind our work is to allow the study of highly excited states and energy spectra of two-dimensional quantum dots and billiard systems with a single versatile code, e.g., in quantum …

Tuning of QoS Aware Load Balancing Algorithm (QoS–LB) for Highly Loaded Server Clusters

2001

This paper introduces a novel algorithm for content based switching. A content based scheduling algorithm (QoS Aware Load Balancing Algorithm, QoS-LB) which can be used at the front-end of the server cluster is presented. The front-end switch uses the content information of the requests and the load on the back servers to choose the server to handle each request. At the same time, different Quality of Service (QoS) classes of the customers can be considered as one parameter in the load balancing algorithm. This novel feature becomes more important when service providers begin to offer the same services for customers with different priorities.

A New Genetic Approach for the Partitioning Problem in Distributed Virtual Environment Systems

2004

The Partitioning problem is a key issue in the design of Distributed Virtual Environment (DVE) systems based on a server-network architecture. This problem consist of efficiently assigning the clients of the simulation (avatars) to the system servers. Despite the existing literature proposes different evolutive approaches for solving this NP-hard problem, an approach based on genetic algorithms is considered as the current best partitioning mechanism.

Performance Evaluation of CANIT Algorithm in Presence of Congestion Losses

2001

In this paper, we analize by queuing-simulation CANIT (Congestion Avoidance with Normalized Interval of Time) algorithm performances in presence of congestion losses. In a former work [3], we proposed the algorithm (CANIT) for TCP (Transmission Control Protocol) congestion avoidance phase in order to improve fairness during this phase, and we showed that using CANIT algorithm in an environment without loss, instead of standard congestion avoidance algorithm improves both congestion avoidance fairness and bandwith utilization for long RTT connections. In this paper, we consider congestion losses and show that the fairness as well as the bandwith utilization are more efficient when using CANI…

Graph Filtering with Quantization over Random Time-varying Graphs

2019

Distributed graph filters can be implemented over wireless sensor networks by means of cooperation and exchanges among nodes. However, in practice, the performance of such graph filters is deeply affected by the quantization errors that are accumulated when the messages are transmitted. The latter is paramount to overcome the limitations in terms of bandwidth and computation capabilities in sensor nodes. In addition to quantization errors, distributed graph filters are also affected by random packet losses due to interferences and background noise, leading to the degradation of the performance in terms of the filtering accuracy. In this work, we consider the problem of designing graph filte…