6040707
A Performance and Scalability Analysis of the BlueGene/L Architecture
Based on a set of measurements done on the 512-node 500MHz prototype and early results on a 2048 node 700MHz BlueGene/L machine at IBM Watson, we present a performance and scalability analysis of the architecture from low-level characteristics to large-scale applications. In addition, we present predictions using our models for the performance of two representative applications from the ASC² workload on the full BlueGene/L configuration of 64K nodes. We have compared the measured values for several of the benchmarks in our suite against the predicted numbers from our performance models. In general, the error bars were relatively low. A comparison between the performance of BlueGene/L and the ASCI Q, the largest supercomputer in the US, is presented, also based on our predictive performance models.
14275613
An empirical performance analysis of commodity memories in commodity servers
This work details a performance study of six different types of commodity memories in two commodity server nodes. A number of micro-benchmarks are used that measure low-level performance characteristics, as well as two applications representative of the ASC workload. The memories vary both in terms of performance, including latency and bandwidths, and in terms of their physical properties and manufacturer. The two server nodes analyzed were an Itanium-II Madison based system, and a Xeon based system. All memories can be used within both of these processing nodes. This allows the performance of the memories to be directly examined while keeping all other factors within a node the same (processor, motherboard, operating system etc.). The results of this study show that there can be a significant difference in application performance depending on the actual memory used - by as much as 20%. The achieved performance is a result of the integration of the memory into the node as well as how the applications actually utilize it.
53225813
Architecture - A performance comparison through benchmarking and modeling of three leading supercomputers: blue Gene/L, Red Storm, and Purple
11728820
The Hugin Tool for Probabilistic Graphical Models
As the framework of probabilistic graphical models becomes increasingly popular for knowledge representation and inference, the need for efficient tools for its support is increasing. The Hugin Tool is a general purpose tool for construction, maintenance, and deployment of Bayesian networks and influence diagrams. This paper surveys the key functionality of the Hugin Tool and reports on new advances of the tool. Furthermore, an empirical analysis reports on the efficiency of the Hugin Tool on common inference and learning tasks.
7987492
Reconsidering the "Software Crisis": A Study of Hypermedia Systems Development
With the advent and growth of the Web, hypermedia information systems have propagated within and beyond organizations. Much concern has been expressed about the quality of hypermedia systems being developed and the apparent absence of disciplined development practices. There has been talk that the infamous “software crisis” is afflicting hypermedia systems development, allegedly brought about by shoddy project management, inadequate requirements analysis and planning, and ad hoc “quick and dirty” development approaches. This paper reports on the findings of a survey of 438 organisations in Ireland, the objectives of which were to test the validity of assertions of a “hypermedia crisis”, and to explore what mechanisms if any are being used to guide and control hypermedia systems development. The preliminary conclusions are that hypermedia development is much more disciplined that popularly believed, and the state of practice is much healthier than depicted by many academic researchers.
120859220
Analysis of trapped entanglements in polymer networks
This work reviews different standard methods to analyze trapped entanglements of polymer networks and discusses their advantages and drawbacks with respect to simplicity, computing time and accuracy of the results. Since this standard analysis is based on the pairwise test of closed cycles, two algorithms for the determination of these cycles are introduced and compared. The decomposition into meshes creates unsolved problems regarding the non-ambiguity and the completeness of the received results. Examples are given in order to show their effects and to start further discussion to receive more convenient methods. As one possible solution Vassiliev's invariants are discussed and an approximation method is introduced to correct the possible multiple counting of entanglements.
34671312
Hugin - The Tool for Bayesian Networks and Influence Diagrams
9385354
The Hugin Tool for Learning Bayesian Networks
In this paper, we describe the Hugin Tool as an efficient tool for knowledge discovery through construction of Bayesian networks by fusion of data and domain expert knowledge. The Hugin Tool supports structural learning, parameter estimation, and adaptation of parameters in Bayesian networks. The performance of the Hugin Tool is illustrated using real-world Bayesian networks, commonly used examples from the literature, and randomly generated Bayesian networks.