32057483
An Evolutionary Algorithm for the Design of Hybrid Fiber Optic-Coaxial Cable Networks in Small Urban Areas
Telecommunication is one of the fastest growing business sectors. Future networks will need to integrate a wide variety of services demanding different qualities and capacities from the network. In this paper, network architecture based on hybrid fiber optic-coaxial cable (HFC) is proposed to develop cable integrated telematic services. An evolutionary algorithm is presented to solve the problem in suitable computation times when dealing with real times civil works problems. Finally we present the results over both problem library and real life scenarios.
206167311
Genetic algorithm for planning cable telecommunication networks
Abstract Optical fiber networks over synchronous digital hierarchy operating on ATM mode appear as one of the best alternatives for the new high-speed telecommunications networks. The network management requires planning studies so that the designed networks allow efficient operation in real time. A quantitative model evaluating the global topological design of an optical fiber network over synchronous digital hierarchy is described. The model includes the economic aspects involved in the project, the civil works, the capacity evaluation costs and the introduction of reliability conditions. A genetic approach based on the exploitation of the Kuhn–Tucker optimality conditions is proposed to solve the model.
16750894
A Genetic Algorithm for Solving a Production and Delivery Scheduling Problem with Time Windows
This paper deals with the problem of selecting and scheduling a set of orders to be processed by a manufacturing plant and immediately delivered to the customer site. Constraints to be considered are the limited production capacity, the available number of vehicles and the time windows within which orders must be served. We describe the problem relating it to similar problems studied in the literature. A genetic algorithm to solve the problem is developed and tested empirically with randomly generated problems. Comparisons with an exact procedure and a tabu search procedure show that the method finds very good-quality solutions.
8103944
Evaluating IA-32 web servers through simics: a practical experience
Nowadays, the use of multiprocessor systems is not just limited to typical scientific applications, but these systems are increasingly being used for executing commercial applications, such as databases and web servers. Therefore, it becomes essential to study the behavior of multiprocessor architectures under commercial workloads. To accomplish this, we need simulators able to model not only the CPU, memory and interconnection network but also other aspects that are critical in the execution of commercial workloads, such as I/O subsystem and operating system. In this paper, we present our first experiences using Simics, a simulator which allows full-system simulation of multiprocessor architectures covering all the topics previously mentioned. Using Simics we carry out a detailed performance study of a static web content server, showing how changes in some architectural parameters, such as number of processors and cache size, affect final performance. The results we have obtained corroborate the intuition of increasing performance of a dual-processor web server opposite to a single-processor one, and at the same time, allow us to check out Simics limitations. Finally, we compare these results with those that are obtained on real machines.
16699598
Design and implementation requirements for CORBA lightweight components
This paper describes the guidelines we followed and the requirements we stated while designing and implementing the CORBA Lightweight Components (CORBA-/spl Lscr/C) Component Model. CORBA-/spl Lscr/C is a lightweight distributed reflective component model based on CORBA. Instead of using a traditional client/server model, it imposes a peer network model in which the whole network act as a repository for managing and assigning the whole set of resources: components, CPU cycles, memory, etc. Thus, application deployment is automatically and adaptively performed at run-time. Requirements for component description, packaging, deployment, reflection, logical network cohesion, distributed resource queries and fault-tolerant protocols are identified. Finally, we show the validity of the identified requirements in dealing with CSCW and Grid Computing applications and show how current component models fail on addressing some of these requirements.
9781969
CORBA Lightweight Components : A Model for Distributed Component-BasedHeterogeneous Computation
In this article we present CORBA Lightweight Components, CORBA-LC, a new network-centered reflective component model which allows building distributed applications assembling binary independent components spread on the network. It provides a peer network view in which the component dependencies are managed automatically to perform an intelligent application run-time deployment, leading to better utilization of resources. We show the validity of the CORBA-LC approach in dealing with CSCW and Grid Computing applications.
1090384
Reducing 3D wavelet transform execution time through the Streaming SIMD Extensions
This paper focuses on reducing the execution time of the video compression algorithms based on the 3D wavelet transform. We present several optimizations that could not be applied by the compiler due to the characteristics of the algorithm. First, we use the Streaming SIMD Extensions (SSE) for some of the dimensions of the sequence (y and time), in order to reduce the number of floating point instructions, exploiting data level parallelism. Then, we apply loop unrolling and data prefetching to critical parts of the code, and finally the algorithm is vectorized by columns, allowing the use of SIMD instructions for the y dimension. Results show improvements of up to 1.54 over a version compiled with the maximum optimizations of the Intel CIC++ compiler Our experiments also show that, allowing the compiler to perform some of these optimizations (i.e. automatic code vectorization) causes performance slowdown which demonstrates the effectiveness of our optimizations.