41430454
An Evaluation of Parallel Computing in PC Clusters with Fast Ethernet
Currently, clusters of Personal Computers (PCs) with sharing Fast Ethernet may offer a significant price/performance ratio in parallel processing. This paper presents a study of the promising possibilities of parallelism in this environment, using both a classical numerical method to solve a differential equation and an innovative algorithm to solve the statistical problem of density estimation. In addition, and to compare, some comparisons with an IBM SP2 are carried out.
17330539
Automatic Code Generation for Non-Funtional Aspects in the CORBA-LC Component Model
Component Technology allows a better modularity and reusability of applications. Components are even better suited for the development of distributed applications, as those applications can be partitioned in terms of components installed and running (deployed) in the di erent hosts participating in the system. Components, apart from implementing their own functionality, have other requirements in term of non-functional aspects such as CPU power utilization, load balancing, fault-tolerance, etc. The code for ensuring these aspects can be automatically generated based on the requirements stated by components and applications, thus leveraging the component implementer of having to deal with these non-functional aspects. In this paper we present (1) architecture of the automatic code generator, and (2) the characteristics of the generated code for dealing with the aforementioned non-functional aspects in the context of CORBA LC.CORBA LC is a lightweight distributed re ective component model based on CORBA that imposes a peer network model in which the whole network acts as a repository for managing and assigning the whole set of resources: components, CPU cycles, memory, etc.
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.
1081050
An efficient implementation of a 3D wavelet transform based encoder on hyper-threading technology
Video medical compression algorithms based on the 3D wavelet transform obtain both excellent compression rates and very good quality, at the expense of a higher execution time. The goal of this work is to improve the execution time of our 3D Wavelet Transform Encoder. We examine and exploit the characteristics and advantages of a hyper-threading processor. The Intel Hyper-threading Technology (HT) is a technique based on simultaneous multi-threading (SMT), which allows several independent threads to issue instructions to multiple functional units in a single cycle. In particular, we present two approaches: data-domain and functional, which differ in the way that the decomposition of the application is performed. The first approach is based on data division, where the same task is performed simultaneously by each thread on an independent part of the data. In the second approach, the processing is divided in different tasks that are executed concurrently on the same data set. Based on the latter approach, we present three proposals that differ in the way that the tasks of the application are divided between the threads. Results show speedups of up to 7% and 34% by the data-domain and functional decomposition, respectively, over a version executed without hyper-threading technology. Finally, we design several implementations of the best method with Pthreads and OpenMP using functional decomposition. We compare them in terms of execution speed, ease of implementation and maintainability of the resulting code.
11677088
Owner Prediction for Accelerating Cache-to-Cache Transfer Misses in a cc-NUMA Architecture
Cache misses for which data must be obtained from a remote cache (cache-to-cache transfer misses) account for an important fraction of the total miss rate. Unfortunately, cc-NUMA designs put the access to the directory information into the critical path of 3-hop misses, which significantly penalizes them compared to SMP designs. This work studies the use of owner prediction as a means of providing cc-NUMA multiprocessors with a more efficient support for cache-to-cache transfer misses. Our proposal comprises an effective prediction scheme as well as a coherence protocol designed to support the use of prediction. Results indicate that owner prediction can significantly reduce the latency of cache-to-cache transfer misses, which translates into speed-ups on application performance up to 12%. In order to also accelerate most of those 3-hop misses that are either not predicted or mispredicted, the inclusion of a small and fast directory cache in every node is evaluated, leading to improvements up to 16% on the final performance.
605710
Leakage Energy Reduction in Value Predictors through Static Decay
As process technology advances toward deep submicron (below 90 nm), static power becomes a new challenge to address for energy-efficient high performance processors, especially for large on-chip array structures such as caches and prediction tables. Value prediction appeared as an effective way of increasing processor performance by overcoming data dependences, but at the risk of becoming a thermal hot spot due to the additional power dissipation. This paper proposes the design of low-leakage value predictors by applying static decay techniques in order to disable unused entries from the prediction tables. We explore decay strategies suited for the three most common Value predictors (STP, FCM and DFCM) studying the particular tradeoffs for these prediction structures. Our mechanism reduces VP leakage energy efficiently without compromising VP accuracy nor processor performance. Results show average leakage energy reductions of 52%, 65% and 75% for the STP, DFCM and FCM value predictors, respectively.
25679945
A Comparison of GRASP and an Exact Method for Solving a Production and Delivery Scheduling Problem
In this paper we consider the production and delivery scheduling problem, a problem that deals with the selection of orders to be processed by a manufacturing plant and immediately delivered to the customer site. Orders have a fixed due date and must be prepared in a single plant with limited capacity. A limited number of vehicles are available for delivery. A ready-mix concrete manufacturing case study has motivated this research. We describe an exact method to find optimal solutions based on the construction of a graph that collects all feasible solutions. We also describe a greedy randomized adaptive search (GRASP) for the problem that finds good, though not necessarily optimal, solutions.
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.
7433683
Viral systems: A new bio-inspired optimisation approach
The paper presents a new approach to deal with combinatorial problems. It makes use of a biological analogy inspired by the performance of viruses. The replication mechanism, as well as the hosts' infection processes is used to generate a metaheuristic that allows the obtention of valuable results. The viral system (VS) theoretical context is described and it is applied to a library of medium-to-large-sized cases of the Steiner problem for which the optimal solution is known. The method is compared with the metaheuristics that have provided the best results for the Steiner problem. The VS provides better solutions than genetic algorithms and certain tabu search approaches. For the most sophisticated tabu search approaches (the best metaheuristic approximations to the Steiner problem solution) VS provides solutions of similar quality.
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.