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.
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.
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.
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.
6582409
A Low Overhead Fault Tolerant Coherence Protocol for CMP Architectures
It is widely accepted that transient failures will appear more frequently in chips designed in the near future due to several factors such as the increased integration scale. On the other hand, chip-multiprocessors (CMP) that integrate several processor cores in a single chip are nowadays the best alternative to more efficient use of the increasing number of transistors that can be placed in a single die. Hence, it is necessary to design new techniques to deal with these faults to be able to build sufficiently reliable chip multiprocessors (CMPs). In this work, we present a coherence protocol aimed at dealing with transient failures that affect the interconnection network of a CMP, thus assuming that the network is no longer reliable. In particular, our proposal extends a token-based cache coherence protocol so that no data can be lost and no deadlock can occur due to any dropped message. Using GEMS full system simulator, we compare our proposal against a similar protocol without fault tolerance (TOKENCMP). We show that in absence of failures our proposal does not introduce overhead in terms of increased execution time over TOKENCMP. Additionally, our protocol can tolerate message loss rates much higher than those likely to be found in the real world without increasing execution time more than 15%
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.
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.
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.
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.
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.