167,852 research outputs found
Evaluation of the Cedar memory system: Configuration of 16 by 16
Some basic results on the performance of the Cedar multiprocessor system are presented. Empirical results on the 16 processor 16 memory bank system configuration, which show the behavior of the Cedar system under different modes of operation are presented
CEDAR: tools for event generator tuning
I describe the work of the CEDAR collaboration in developing tools for tuning
and validating Monte Carlo event generator programs. The core CEDAR task is to
interface the Durham HepData database of experimental measurements to event
generator validation tools such as the UCL JetWeb system - this has
necessitated the migration of HepData to a new relational database system and a
Java-based interaction model. The "number crunching" part of JetWeb is also
being upgraded, from the Fortran HZTool library to the new C++ Rivet system and
a generator interfacing layer named RivetGun. Finally, I describe how Rivet is
already being used as a central part of a new generator tuning system, and
summarise two other CEDAR activities, HepML and HepForge.Comment: 13 pages, prepared for XI International Workshop on Advanced
Computing and Analysis Techniques in Physics Research, Amsterdam, April 23-27
200
Preliminary basic performance analysis of the Cedar multiprocessor memory system
Some preliminary basic results on the performance of the Cedar multiprocessor memory system are presented. Empirical results are presented and used to calibrate a memory system simulator which is then used to discuss the scalability of the system
Simulation of Ground-Water Flow in the Cedar River Alluvial Aquifer Flow System, Cedar Rapids, Iowa Scientific
The Cedar River alluvial aquifer is the primary source of municipal water in the Cedar Rapids, Iowa, area. Since 1992, the U.S. Geological Survey, in cooperation with the City of Cedar Rapids, has investigated the hydrogeology and water quality of the Cedar River alluvial aquifer. This report describes a detailed analysis of the ground-water flow system in the alluvial aquifer, particularly near well field areas. The ground-water flow system in the Cedar Rapids area consists of two main components, the unconsolidated Quaternary deposits and the underlying carbonate bedrock that has a variable fracture density. Quaternary deposits consist of eolian sand, loess, alluvium, and glacial till. Devonian and Silurian bedrock aquifers overlie the Maquoketa Shale (Formation) of Ordovician age, a regional confining unit. Ground-water and surface-water data were collected during the study to better define the hydrogeology of the Cedar River alluvial aquifer and Devonian and Silurian aquifers. Stream stage and discharge, ground-water levels, and estimates of aquifer hydraulic properties were used to develop a conceptual ground-water flow model and to construct and calibrate a model of the flow system. This model was used to quantify the movement of water between the various components of the alluvial aquifer flow system and provide an improved understanding of the hydrology of the alluvial aquifer
Flexible Session Management in a Distributed Environment
Many secure communication libraries used by distributed systems, such as SSL,
TLS, and Kerberos, fail to make a clear distinction between the authentication,
session, and communication layers. In this paper we introduce CEDAR, the secure
communication library used by the Condor High Throughput Computing software,
and present the advantages to a distributed computing system resulting from
CEDAR's separation of these layers. Regardless of the authentication method
used, CEDAR establishes a secure session key, which has the flexibility to be
used for multiple capabilities. We demonstrate how a layered approach to
security sessions can avoid round-trips and latency inherent in network
authentication. The creation of a distinct session management layer allows for
optimizations to improve scalability by way of delegating sessions to other
components in the system. This session delegation creates a chain of trust that
reduces the overhead of establishing secure connections and enables centralized
enforcement of system-wide security policies. Additionally, secure channels
based upon UDP datagrams are often overlooked by existing libraries; we show
how CEDAR's structure accommodates this as well. As an example of the utility
of this work, we show how the use of delegated security sessions and other
techniques inherent in CEDAR's architecture enables US CMS to meet their
scalability requirements in deploying Condor over large-scale, wide-area grid
systems
Implementing an engineering data management system for the LHC accelerator and experiments: the CEDAR project
The huge quantities of data required for the design, building and operation of the LHC and its experiments require consistent management and storage. The CEDAR project aims at implementing an Engineering Data Management System (EDMS) at CERN. After having defined what is an EDMS and what are the expected benefits for the LHC we present the activities held in CEDAR, during the selection and pilot project phases. Lessons learned and conclusions reached through the pilot projects are then summarised
Recommended from our members
Transcriptome analysis of the brown rot fungus \u3cem\u3eGloeophyllum trabeum\u3c/em\u3e during lignocellulose degradation
Brown rot fungi have great potential in biorefinery wood conversion systems because they are the primary wood decomposers in coniferous forests and have an efficient lignocellulose degrading system. Their initial wood degradation mechanism is thought to consist of an oxidative radical-based system that acts sequentially with an enzymatic saccharification system, but the complete molecular mechanism of this system has not yet been elucidated. Some studies have shown that wood degradation mechanisms of brown rot fungi have diversity in their substrate selectivity. Gloeophyllum trabeum, one of the most studied brown rot species, has broad substrate selectivity and even can degrade some grasses. However, the basis for this broad substrate specificity is poorly understood. In this study, we performed RNA-seq analyses on G. trabeum grown on media containing glucose, cellulose, or Japanese cedar (Cryptomeria japonica) as the sole carbon source. Comparison to the gene expression on glucose, 1,129 genes were upregulated on cellulose and 1,516 genes were upregulated on cedar. Carbohydrate Active enZyme (CAZyme) genes upregulated on cellulose and cedar media by G. trabeum included glycoside hyrolase family 12 (GH12), GH131, carbohydrate esterase family 1 (CE1), auxiliary activities family 3 subfamily 1 (AA3_1), AA3_2, AA3_4 and AA9, which is a newly reported expression pattern for brown rot fungi. The upregulation of both terpene synthase and cytochrome P450 genes on cedar media suggests the potential importance of these gene products in the production of secondary metabolites associated with the chelator-mediated Fenton reaction. These results provide new insights into the inherent wood degradation mechanism of G. trabeum and the diversity of brown rot mechanisms
Old-growth Characteristics of Northern White-cedar Stands
Northern white-cedar (Thuja occidentalis; hereafter white-cedar) communities have received relatively little research attention, and managers lack the tools used in the management of other commercial tree species. This includes the recognition of old-growth characteristics and the differentiation between old-growth and partially harvested stands, particularly in the context of Forest Stewardship Council (FSC-US) certification. Specifically, there is very little information about characteristics that define old-growth white-cedar stands despite the species’ abundance and wide distribution. Regional indices for late-successional or old-growth stands (Whitman and Hagan, 2007) do not include white-cedar. Forests dominated by white-cedar represent a type that currently lacks quantitative benchmarks for old-growth characteristics.
To identify the structural characteristics unique to old-growth white-cedar stands, we inventoried 16 old-growth and 17 partially harvested stands in Maine and New Brunswick. In Chapter 1, we report the outcomes from a range of structural metrics commonly used in forest management such as basal area (BA, m² ha-1), quadratic mean diameter (QMD, cm), large tree (≥ 40 cm dbh) density, and volumes of coarse woody material (CWM, m³ ha-1), along with a set of structural complexity indices (e.g., diameter distribution index, mingling index). Two significant predictors were identified that, in combination, differentiate old-growth from partially harvested white-cedar stands: advanced-decay coarse woody material volume (logs in decay stages 4 and 5 using a 5-stage system) and live tree QMD. No structural complexity indices were useful in predicting old-growth status. Our research improves the understanding of old-growth characteristics in white-cedar stands and provides an important tool for the successful management of white-cedar.
In Chapter 2, we present a practitioner-oriented guide to aid in the application of our findings by forest managers. Specifically, we provide an equation for determining the probability that a white-cedar stand has old-growth characteristics, as well as supporting information about how to collect and prepare the data needed to use this prediction tool. Illustrations and photographs are used to demonstrate the forest attributes of interest, and to aid the practitioner in measuring and determining the decay classes of coarse woody material. In addition, we discuss the relevance of our findings to ecological forestry prescriptions. This guide will prove useful for forest managers working under FSC guidelines, wherein the recognition of old-growth characteristics is institutionalized in requirements for reserving old-growth stands and maintaining old-growth characteristics where they are found in managed stands
Comparison of the decomposition behaviors of hardwood and softwood in supercritical methanol
The chemical conversion of Japanese beech (Fagus crenata Blume) and Japanese cedar (Cryptomeria japonica D. Don) woods in supercritical methanol was studied using the supercritical fluid biomass conversion system with a batch-type reaction vessel. Under conditions of 270°C/27 MPa, beech wood was decomposed and liquefied to a greater extent than cedar wood, and the difference observed was thought to originate mainly from differences in the intrinsic properties of the lignin structures of hardwood and softwood. However, such a difference was not observed at 350°C/43 MPa, and more than 90% of both beech and cedar woods were effectively decomposed and liquefied after 30 min of treatment. This result indicates that the supercritical methanol treatment is expected to be an efficient tool for converting the woody biomass to lower-molecular-weight products, such as liquid fuels and useful chemicals
Effect of Habitat on Blow Fly (Diptera: Calliphoridae) Oviposition in Michigan
Forensic entomology applies data gained from insects to aid the criminal justice system. Blow flies (Diptera: Calliphoridae) are usually the first insects to arrive and oviposit (lay eggs) on carrion. Their quick appearance is the foundation for post mortem interval estimations, making any factors that influence their oviposition crucial. This study examined the effects of habitat (forest vs. prairie) on blow fly oviposition timing. Research was conducted in 2015 at Pierce Cedar Creek Institute in Barry County, Michigan. No significant differences were found in oviposition timing or frequency between prairie and forest habitats. Temperature and humidity were not correlated with oviposition timing, which contradicted previous studies. Lucilia coeruleiviridis (Macquart) was the dominant species found, comprising about 90% of collected specimens. The data confirm previous reports that Lucilia species are the first to arrive on carrion
- …