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.
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.
16999625
Memory Subsystem Characterization in a 16-Core Snoop-Based Chip-Multiprocessor Architecture
In this paper we present an exhaustive evaluation of the memory subsystem in a chip-multiprocessor (CMP) architecture composed of 16 cores. The characterization is performed making use of a new simulator that we have called DCMPSIM and extends the Rice Simulator for ILP Multiprocessors (RSIM) with the functionality required to model a contemporary CMP in great detail. 
 
To better understand the behavior of the memory subsystem, we propose a taxonomy of the L1 cache misses found in CMPs which subsequently we use to determine where the hot spots of the memory hierarchy are and, thus, where computer architects have to place special emphasis to improve the performance of future dense single-chip multiprocessors, which will integrate 16 or more processor cores.
18834648
Design and Implementation of a Grid-Enabled Component Container for CORBA Lightweight Components
Although Grid technology appears as a promising infrastructure for global computation and effective resource sharing, the development of Grid Applications is still based in traditional programming models such as Message Passing Interface (MPI), making it difficult to provide a good level of software reuse and productivity. Moreover, the Grid offers an environment where the component technology can be applied to a greater extent than ever, due to the intrinsic security enforced by the Grid, allowing the creation of a successful component market. Component technology accelerates software development enforcing software reuse and sharing. In this article we present CORBA-\(\mathcal{LC}\) and the design of its Container, that manage components and provides them with non-functional aspects such as security, concurrency, distribution, load balancing, fault tolerance, replication, data-parallelism, etc. Component implementors can thus focus only on the component functionality itself, independently of these aspects, provided by the Container. Furthermore, we identify these non-functional aspects in the Grid Computing domain and show the current status of the implementation.
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.
14863266
A Performance Evaluation of P-EDR in Different Parallel Environments
* This work has been partially supported by the Spanish CICYT under grant TIC97-0897-C04-03 Abstract This paper presents an exhaustive performance analysis of the P-EDR algorithm in some parallel machines available nowadays. EDR algorithm is a recent result of our Research Group. It constitutes an extension of the well-known Parzen method, which can be applied when dealing with uncertainty. Management of uncertainty implies heavy computational loads in terms of both calculus and storage, so a parallel version of the algorithm is more adequate to solve this problem in a practical time, especially for samples of large sizes. P-EDR represents our parallel implementation of EDR. Our tests go from an expensive and powerful MPP (as an IBM SP2 constitutes) to a cost-effective solution, as clusters of PCs represent. In these tests we have run the P-EDR algorithm in two distinct clusters of PCs each one with a different type of interconnection network: a low-cost 100 Mbit/s Fast Ethernet and a 1.28 Gbit/s Myrinet. Results obtained confirm parallel computing on networks of PCs as an attractive alternative to MPPs for cost/performance reasons.
32636956
Viral System to Solve Optimization Problems: An Immune-Inspired Computational Intelligence Approach
This paper presents Viral System as a new immune-inspired computational intelligence approach to deal with optimization problems. The effectiveness of the approach is tested on the Steiner problem in networks a well known NP-Hard problem providing great quality solutions in the order of the best known approaches or even improving them.
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.
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.