Catálogo de publicaciones - libros

Network on a chip (NoC) has been proposed to address the inefficiency of buses in the current System on Chips (SoC). However as the chip scales, the probability of errors is also increasing, thus, making fault tolerance a key concern in scaling chips. Transient faults are becoming a major cause of errors in a packet based NoC. A transient error can either corrupt the header or the payload of packet requiring a retransmission from the source. Due to retransmissions, packets arrive out of order at the receiver side. Complex reordering algorithms are required at the receiver side to organize packets before sending them to associated resource. This adds a major overhead as the storage and logic capabilities are limited on a chip. We therefore provide a low-cost, fast and reliable end-to-end protocol for NoC which does not require reordering of the packets at the receiver end. Our protocol performs bitwise logical operations using binary representation of the addresses for the buffers to handle packets, hence making it much faster than conventional algorithms. Furthermore, the protocol is equally applicable to both static as well as dynamic routing environments on a chip.

This work investigates the escalation of leakage power loss in today’s low power processors as their feature size shrinks rapidly. The problem seems to exacerbate as technology scaling dives steadily into Very Deep Submicron (VDSM). A quantitatively analysis has been carried out in several cache systems and has shown that the 1-way set associativity optimizes this power component across various generations.

e-Science Aerospace Integrated Research System(e-AIRS) is one of e-Science projects in KOREA. This system has been developed for aerospace researchers to be offered total research environment which is integrated and collaborative environment to enable computational simulation and remote experiments via portal. This paper presents that the core part of this system is adapted to Teragrid at NCSA. By way of this goal components of e-AIRS system are updated and customized to Teragrd and is added existing grid portal technology. Also this system is interlocked with NCSA tools to use Teragrid resources. Through these efforts e-AIRS offers easy-to-use research environment to aerodynamic researchers on Teragrid.

The influence of the microdefect interactions on the stress intensity factors (SIF’s) at the tip of the macrocracks in cortical bones is considered using one of the linear fracture mechanics models developed by Tamuzs [1]A human bone is a living organism governed by quite complex biological processes. However, at any given moment of time a frame of the human body is a mechanical structure of composite materials (of various mechanical properties for the different types of bones). As it is established experimentally [2], microcracks and other microdefects are present in cortical bones at every stage of life of the bone. They play a vital role in the process of remodeling of the bone. With age, the distances between microcracks are decreasing [10], making “bridges” (uncracked ligament) smaller that causes increase of SIF’s and decrease of the critical fracture load. In another words , a bone fracture can occur even without extraordinary external force. The objective of this work is to provide a mechanistic interpretation of interaction of macro-and microcracks in cortical bones. The structural integrity of a composite material of the bone is obviously vital for the work of the human body frame. Traditionally, the bone quality is defined in terms of bone mineral density (BMD), namely, the amount of bone mineral per unit of volume. The fracture of the bone may occur not only as a result of a single impact but may also be caused by the microcrack interactions resulting in so called stress fracture (without a major impact). Therefore, for comprehensive understanding of the bone fracture it is necessary to study the microstructural interactions in bones. As the linear fracture mechanics is considered by most researchers an appropriate tool for investigating failure processes in bones [2], the analysis of the stress intensity factors governing the hierarchy in macro-microcrack propagation and the amplification (“intrinsic”) and shielding (“extrinsic”) effects is conducted using solutions obtained in [1,4].

This article addresses the problem of solving the collisions through chaining in the simple uniform hashing. The personal contribution consists of the improvement of the algorithm of dispersion through linking, by modifying the linking schema of the elements of the hash table. A contribution presents solving the collisions by creating combined linked ordered lists for storing the elements that have the same hash value. The code returned by the second hash function applied to the key of each element, is used for ordering the elements of the combined linked list. The proof of the performance of the proposed algorithm consists in the computing of the time needed for the search with and without success and of the comparative analysis of the time of execution of the algorithms.

We have built a simulator named, CDLR SPEC 2000. This simulator is based on traces for systems with cache memories. With CDLR SPEC 2000 program we can study, for a memory hierarcy, the next parameters: maping function, block size, writing strategies, replacement algoritm, size of cache memory, number of cache sets (for the set associative caches), number of words form a block. The simulator can be used for the study of cache memory behaviour. Also the CDLR SPEC 2000 program, introduce the calculus of CDLR of a memory hierarchy. A common metric used for the assessment of overall reliability, in a memory hierarchy is the Mean Time To Failure (MTTF), but it doesn’t take into account for the time of data storage in each level. We propose another metric, Cache Data Loss Rate (CDLR), for this reason. We will derive a recurrent formula for computing CDLR, and we will validate it by computer simulation.

A mobile ad hoc network can be defined as a network that is spontaneously deployed and is independent of any static network. The network consist of mobile nodes1 with wireless interfaces and has an arbitrary dynamic topology. The networks suffers from frequent link formation and disruption due to the mobility of the nodes. In this paper we present a token based algorithm for Group Mutual Exclusion in ad hoc mobile networks. The proposed algorithm is adapted from the RL algorithm in [1]. The algorithm requires nodes to communicate with only their current neighbors. The algorithm ensures the mutual exclusion, the bounded delay, and the concurrent entering properties.

The presented paper describes a promising approach of adaptive deployment in CORBA Component Model (CCM). Adaptation, as an essential concept of contemporary distributed systems, is used to improve planning of component deployment. There is described a concept and implementation of mechanisms which, using monitoring infrastructure and simple policy-based engine, allows improving execution efficiency. The presented tool, named CCMAD, is intended for use with OpenCCM platform, an open source Java implementation of CCM model. It is, however, expected that adapting CCMAD for any other CCM platform would not be troublesome.

Data sharing represents one of the key objectives and major challenges of today’s cancer research. CancerGrid, a consortium of clinicians, cancer researchers, computational biologists and software engineers from leading UK institutions, is developing open-standards cancer informatics addressing this challenge. The CancerGrid solution involves the representation of a widely accepted clinical trials model in controlled vocabulary and common data elements (CDEs) as the enabling factor for cancer data sharing. This paper describes a cancer data query system that supports data sharing across CancerGrid-compliant clinical trial boundaries. The formal specification of the query system allows the model-driven development of a flexible, web-based interface that cancer researchers with limited IT experience can use to identify and query common data across multiple clinical trials.

This paper considers the application of computer-based technologies in retail settings and describes the development of a system designed to support the in-store interaction between customer and sales person. The particular application context is that of a made-to-measure shirt shop. A sustained program of research has led to the development of a system that facilitates the selection of shirt components (e.g., fabrics, collars, cuffs) and allows customers to see a virtual representation of a shirt prior to purchase. An iterative and participatory design process has been adopted, and many interface alternatives considered. Results of this work from a usability point of view are presented and implications considered. Advantages for the customers, sales personnel, and shop owners can be identified. However, integration of ‘usable’ computer technology in this complex ‘real world’ setting needs to be improved and further issues remain to be resolved.