bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization techniques for SIMD Fortran compilers
Authors: Knobe Kathleen , Weiss Michael , Lukas Joan D. 
Published: November 2006

AbstractSIMD computer systems offer tremendous potential speed‐ups but aggressive compilation strategies are required to realize this potential. The paper presents the Compass SIMD compiler technology developed while working on a number of SIMD compilers. Although the various targets have much in common, our increased understanding of the SIMD compilation process on each successive project and the differences in the targets themselves has affected the shape of each compiler.
Analysis and transformation in an interactive parallel programming tool
Authors: Kennedy Ken , McKinley Kathryn S. , Tseng Chau‐Wen 
Published: November 2006

AbstractThe ParaScope Editor is a new kind of interactive parallel programming tool for developing scientific Fortran programs. It assists the knowledgeable user by displaying the results of sophisticated program analyses and by providing editing and a set of powerful interactive transformations. After an edit or parallelism‐enhancing transformation, the ParaScope Editor incrementally updates both the analyses and source quickly. This paper describes the underlying implementation of the ParaScope Editor, paying particular attention to the analysis and representation of dependence information and its reconstruction after changes to the program.
Performance benefits of non‐volatile caches in distributed file systems
Authors: Biswas P. , Towsley D. , Ramakrishnan K. K. , Krishna C. M. 
Published: November 2006

AbstractWe study the use of non‐volatile memory for caching in distributed file systems. This provides an advantage over traditional distributed file systems in that the load is reduced at the server without making the data vulnerable to failures. We propose the use of a small non‐volatile cache for writes, at the client and the file server, together with a larger volatile read cache to keep the cost of the caches reasonable.We use a synthetic workload developed from analysis of file I/O traces from commercial production systems and use a detailed simulation of the distributed environment. The service times for the resources of the system were derived from measurements performed on a typical workstation.We show that non‐volatile write caches at the clients and the file server reduce the write response time and the load on the file server dramatically, thus improving the scalability of the system. We examine the comparative benefits of two alternative writeback policies for the non‐volatile write cache. We show that a proposed threshold based writeback policy is more effective than a periodic writeback policy under heavy load. We also investigate the effect of varying the write cache size and show that introducing a small non‐volatile cache at the client in conjunction with a moderate sized non‐volatile server write cache improves the write response time by a factor of four at all load levels.
The Prospero Resource Manager: A scalable framework for processor allocation in distributed systems
Authors: Neuman B. C. , Rao S. 
Published: November 2006

AbstractExisting techniques for allocating processors in parallel and distributed systems are not suitable for use in large distributed systems. In such systems, dedicated multiprocessors should exist as an integral component of the distributed system, and idle processors should be available to applications that need them. The Prospero Resource Manager (PRM) is a scalable resource allocation system that supports the allocation of processing resources in large networks and on multiprocessor systems.PRM employs three types of managers‐the job manager, the system manager and the node manager‐to manage resources in a distributed system. Multiple independent instances of each type of manager exist, reducing bottlenecks. When making scheduling decisions each manager utilizes information most closely associated with the entities for which it is responsible.
Adaptive transport service for high speed networks
Authors: Richards A. , Ginige T. , Seneviratne A. , Buczkowska T. , Fry M. 
Published: November 2006

AbstractIt has been shown that protocol processing represents a severe bottle‐neck for high speed computer networks. The disadvantages of currently proposed solutions are their incompatibility with existing standardised protocol implementations, their complexity and/or their inflexibility. One method of alleviating these limitation is to have an adaptable protocol stack, as proposed in the paper. Preliminary results are presented which show that significant gains in throughput can be achieved while creating a framework suitable for future applications.
Matrix multiplication on the Intel Touchstone Delta
Authors: Huss‐Lederman Steven , Jacobson Elaine M. , Tsao Anna , Zhang Guodong 
Published: November 2006

AbstractMatrix multiplication is a key primitive in block matrix algorithms such as those found in LAPACK. We present results from our study of matrix multiplication algorithms on the Intel Touchstone Delta, a distributed memory message‐passing architecture with a two‐dimensional mesh topology. We analyze and compare three algorithms and obtain an implementation, BiMMeR, that uses communication primitives highly suited to the Delta and exploits the single node assembly‐coded matrix multiplication. Our algorithm is completely general, i.e. able to deal with various data layouts as well as arbitrary mesh aspect ratios and matrix dimensions, and has achieved parallel efficiency of 86 %, with overall peak performance in excess of 8 Gflops on 256 nodes for an 8800 × 8800 matrix. We describe BiMMeR's design and implementation and present performance results that demonstrate scalability and robust behavior over varying mesh topologies.
Determining update latency bounds in Galactica Net
Authors: Clayton S. , Wilson A. , Duckworth R. J. , Michalson W. 
Published: November 2006

AbstractThe paper looks at the problem of ensuring the performance of real‐time applications hosted on Galactica Net, a mesh‐based distributed cache coherent shared memory multiprocessing system. A method for determining strict upper bounds on worst case latencies in wormhole routed networks of known or unknown communication patterns is presented. From this, a tool for determining upper bounds for shared memory update latencies is developed, and it is shown that the update latency of Galactica Net is deterministic. The analytical bounds are then compared with maximum latencies observed in simulations of GNet, with which they compare favorably. Finally, it is shown that the tool for determining update latency bounds is useful for comparing differing GNet system configurations in order to minimize update latency bounds.
Instructional footprinting and semantic preservation in Linda
Authors: Landry Kenneth , Arthur James D. 
Published: November 2006

AbstractLinda is a co‐ordination language designed to support process creation and interprocess communication within conventional computational languages. Although the Linda paradigm touts architectural and language independence, it often suffers performance penalties, particularly on local area network platforms. Instructional footprinting is an optimization technique with the primary goal of enhancing the execution speed of Linda programs. The two main aspects of instructional footprinting are instructional decomposition and code motion. The paper addresses the semantic issues encountered when the Linda primitives, IN and RD, are decomposed and moved past other Linda operations. Formal semantics are given as well as results showing significant speed‐up (as high as 100%) when instructional footprinting is used.
A parallel dynamic load‐balancing algorithm for solution‐adaptive finite element meshes on 2D tori
Authors: Chung Yeh‐Ching , Yeh Yaa‐Jyun , Liu J.‐S 
Published: November 2006

AbstractTo efficiently execute a finite element program on a 2D torus, we need to map nodes of the corresponding finite element graph to processors of a 2D torus such that each processor has approximately the same amount of computational load and the communication among processors is minimized. If nodes of a finite element graph do not increase during the execution of a program, the mapping only needs to be performed once. However, if a finite element graph is solution‐adaptive, that is, nodes of a finite element graph increase discretely due to the refinement of some finite elements during the execution of a program, a dynamic load‐balancing algorithm has to be performed many times in order to balance the computational load of processors while keeping the communication cost as low as possible. In the paper we propose a parallel dynamic load‐balancing algorithm (LB) to deal with the load‐imbalancing problem of a solution‐adaptive finite element program on a 2D torus. The algorithm uses an iterative approach to achieve load‐balancing. We have implemented the proposed algorithm along with two parallel mapping algorithms, parallel orthogonal recursive bisection (ORB) and parallel recursive mincut bipartitioning (MC), on a simulated 2D torus. Three criteria, the execution time of load‐balancing algorithms, the computation time of an application program under different load balancing algorithms, and the total execution time of an application program (under several refinement phases) are used for performance evaluation. Simulation results show that (1) the execution of LB is faster than those of MC and ORB; (2) the mappings of LB are better than those of ORB and MC; and (3) the speedups of LB are better than those of ORB and MC.
Symmetrical hopping: A scalable scheduling algorithm for irregular problems
Authors: Wu Min‐You 
Published: November 2006

AbstractA run‐time support is necessary for parallel computations with irregular and dynamic structures. One important component in the support system is the run‐time scheduler which balances the working load in the system. We present a new algorithm, Symmetrical Hopping, for dynamic scheduling of ultra‐lightweight processes. It is a dynamic, distributed, adaptive and scalable scheduling algorithm. This algorithm is described and compared to four other algorithms that have been proposed in this context, namely the randomized allocation, the sender‐initiated scheduling, the receiver‐initiated scheduling, and the gradient model. The performance of these algorithms on Intel Touchstone Delta is presented. The experimental results show that the Symmetrical Hopping algorithm achieves much better performance due to its adaptiveness.
Uplink PID power control technique for TDMA‐based cellular radio systems
Authors: Weng Chien‐Erh , Lain Jenn‐Kaie , Shen Chia‐Huei , Wen Jyh‐Horng 
Published: November 2006

AbstractThe efficient management of wireless resource is essential to the success of wireless systems. While power control is traditionally considered to be a means to counteract the detrimental effects of channel fading, it is also a flexible mechanism that achieves high link quality, high bandwidth utilization, and low power consumption, which are mainly driven in cellular radio systems. Once the power control algorithm provides a lower outage probability, the SUs experienced adequate link quality need not to competitively increase their transmission power. Spontaneously, the systems with lower power consumption and better bandwidth efficiency are achieved. In this paper, a novel power control based on the proportional‐integration‐derivative (PID) controller is proposed, and its performance with an autonomous closed‐loop uplink power control model under the time division multiple access (TDMA) systems is presented. Computer simulation is used to illustrate the performance of the proposed power control algorithm in a cellular radio system with Rayleigh fading channels. The results show that our proposed power control algorithm is remarkably superior to several previous power control methods, especially in a short power control period. Copyright © 2006 John Wiley & Sons, Ltd.
Adiponectin as a therapeutic target for obesity‐related metabolic and cardiovascular disorders
Authors: Wang Yu , Lam Karen S.L. , Xu Aimin 
Published: November 2006

AbstractObesity is the major risk factor for the metabolic syndrome, which encompasses a cluster of inter‐related metabolic risk factors for type 2 diabetes mellitus (T2DM), atherosclerosis, and cardiovascular diseases. Adiponectin, a major adipokine secreted from adipocytes, plays an important role in obesity‐related metabolic and cardiovascular diseases. Longitudinal studies from different ethnic groups have identified low levels of plasma adiponectin (hypoadiponectinemia) to be an independent risk factor for T2DM, hypertension, and coronary artery diseases. On the other hand, results from various animal models have demonstrated the role of adiponectin as an insulin‐sensitizer with potent anti‐diabetic, anti‐atherogenic, anti‐inflammatory, and cardio‐protective activities. Therefore, upregulation of endogenous adiponectin production by pharmacological and/or dietary interventions might have multiple beneficial effects on obesity‐related disorders. A number of pharmacological agents that increase adiponectin production have recently been identified. Among them, the anti‐diabetic actions of the PPARγ agonists, thiazolidinediones (TZDs), are mediated, at least in part, by induction of adiponectin expression. Here, we summarize the recent progress on clinical and pharmacological studies of adiponectin, and discuss the utility of adiponectin as a target to develop novel therapies for treatment and prevention of obesity‐related metabolic and cardiovascular diseases. Drug Dev. Res. 67:677–686, 2006. © 2006 Wiley‐Liss, Inc.
Recent progress on geometric algorithms for approximating functions: Toward applications to data analysis
Authors: Tokuyama Takeshi 
Published: November 2006

AbstractData simplification is an extremely important issue in our current information‐oriented society. Normally, a real‐world database contains a massive amount of raw data, and when we consider the data as a distribution function, it has fluctuations due to sampling errors, outliers, and/or invalid inputs. Therefore, for data analysis technology such as data mining, it is important to approximate the input data by a simplified function. There are various approaches to function approximation, and functional analytical methods and learning‐based techniques are quite popular. Apart from them, computational geometric approach based on optimization using discrete algorithms is widely studied. However, the conventional application of computational geometrical techniques is pattern matching, and to apply them to data analysis, their formulation and optimization criteria must be changed accordingly. Therefore, various difficulties and computational barriers arise, which must be eliminated or avoided. In this paper, we discuss data approximation in computational geometry and describe current trends centered on the author's latest research. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 1–12, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20297
Ionic dispersion in nanofluidics
Authors: De Leebeeck Angela , Sinton David 
Published: November 2006

AbstractAn analytical solution for dispersion of ionic and neutral solutes in nanoscale channels is presented. Results suggest that in the presence of relatively thick electrical double layers (EDLs) characteristic of nanofluidics, the dispersion of ionic solutes differs from that of neutral solutes on which previous theory is based. Ionic dispersion for circular cross‐section channels is quantified as a function of a valance parameter, the relative EDL thickness, and the form of the velocity profile. Two unique mechanisms governing ionic dispersion in both pressure‐ and electrokinetically driven flows are identified. The results of the analytical solution, employing the linearized form of the Poisson–Boltzmann equation, are supported and extended by the results of an independent computational model employing the nonlinear Poisson–Boltzmann equation. Applicability of the computational results is not limited by the Debye–Hückel approximation. Collectively, these results indicate that dispersion of ionic species in nanoscale channels is markedly charge dependent, and substantially deviates from that of neutral solutes in the same flow.
Microchip electrophoresis with wall‐jet electrochemical detector: Influence of detection potential upon resolution of solutes
Authors: Pumera Martin , Merkoçi Arben , Alegret Salvador 
Published: November 2006

AbstractThis report studies the electrochemical response of wall‐jet detector for microchip electrophoresis (µCE). It shows that in wall‐jet configuration, the electrochemical detector operates in coulometric mode and that there is an influence of detection potential upon peak width and therefore upon the resolution of solutes. Upon raising the detection potential from +0.3 to +0.9 V, the resolution between model analytes, dopamine and catechol, increases from 0.63 to 2.90. The reasons for this behavior originate in wall‐jet detector design and in its typically significant higher detector volume than the volume of injected sample. The conversion efficiency of the wall‐jet electrochemical detection cell was found to be 97.4% for dopamine and 98.0% for catechol. The paper brings deeper understanding of operations of wall‐jet electrochemical detectors for microchip devices, and it explains previously reported significantly sharper peaks when electrocatalytic electrodes (i.e., palladium and carbon nanotube) were used in µCE‐electrochemistry wall‐jet detector.
Production of Iridoids and Phenolics by Transformed Harpagophytum procumbens Root Cultures
Authors: Georgiev M. , Heinrich M. , Kerns G. , Pavlov A. , Bley T. 
Published: November 2006

AbstractHarpagophytum procumbens (Devil's claw) is an important medicinal plant, which tubers are used for the treatment of different inflammatory diseases. In this study, the time courses of growth of Devil's claw hairy roots and accumulation of intracellular total iridoids and phenolics were investigated during cultivation under submerged conditions. After 21 days of growth in liquid hormone‐free MS medium, a growth index of 81.3 was achieved and the accumulated biomass reached 0.58 g/flask. It was found that the time courses of total iridoids and phenolics production showed almost the same patterns with a maximum on day 21 from the beginning of cultivation (15.93 mg harpagoside equivalents/L and 261 mg gallic acid equivalents/L, respectively). The methanolic extracts possessed relatively high DPPH‐radical scavenging properties (IC50 4.08 mg/mL), while for the culture media no antiradical activity was detected. According to our best knowledge, the present report is the first one dealing with the investigation of transformed root cultures from Harpagophytum procumbens plants.
Adsorption of pure carbon dioxide and methane on dry coal from the sulcis coal province (SW Sardinia, Italy)
Authors: Ottiger Stefan , Pini Ronny , Storti Giuseppe , Mazzotti Marco , Bencini Roberto , Quattrocchi Fedora , Sardu Giorgio , Deriu Giuseppe 
Published: November 2006

AbstractEnhanced coalbed methane recovery (ECBM) increases the recovery of the methane present in a coal seam by injecting CO2 at high pressure. It is attractive from two perspectives, the valuable methane recovered and the storage of the greenhouse gas CO2 for geological times. In the framework of a feasibility study for the Sulcis Coal Province in Italy, the adsorption of pure CO2 and CH4 on dry coal has been measured at 45 and 60°C, using a magnetic suspension balance with in situ density measurement. The results show that the CO2 adsorption isotherms on coal are similar to those for other standard adsorbents such as silica gel and activated carbon. From the excess adsorption isotherms, the absolute adsorption is calculated using the assumption of constant volume of the adsorbed phase. As expected, CO2 get adsorbed more than CH4 in all cases. The Sulcis coal can uptake CO2 at the reservoir conditions in an amount of about 10% of its mass. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
The incidence of first‐onset psychotic symptoms and paranoid ideation in a representative population sample followed from age 70–90 years. Relation to mortality and later development of dementia
Authors: Östling S. , Pálsson S. P. , Skoog I. 
Published: November 2006

AbstractBackgroundLimited data are available on the incidence of psychotic symptoms in the elderly.ObjectiveTo elucidate the incidence of first‐onset psychotic symptoms in the elderly and their relation to mortality and later development of dementia.MethodA population‐sample (n = 392) born 1901–1902 was assessed from age 70–90 with psychiatric examinations, medical record reviews and from age 85, also with key‐informant interviews. Individuals developing dementia were excluded.ResultThe cumulative incidence of first‐onset psychotic symptoms was 4.8% (8.0% including key‐informant reports in the total sample) and 19.8 % in those who survived to age 85. Sixty‐four percent of those with first‐onset hallucinations later developed dementia, compared to 30% of those with delusions and 25% of those without psychotic symptoms.ConclusionsOne fifth of non‐demented elderly who survives up to age 85 develops first‐onset psychotic symptoms. Hallucinations predict dementia, but most elderly individuals with first‐onset psychotic symptoms do not develop dementia. Copyright © 2006 John Wiley & Sons, Ltd.
Pores in synthetic nerve conduits are beneficial to regeneration
Authors: Vleggeert‐Lankamp C.L.A.M. , de Ruiter G.C.W. , Wolfs J.F.C. , Pêgo A.P. , van den Berg R.J. , Feirabend H.K.P. , Malessy M.J.A. , Lakke E.A.J.F. 
Published: November 2006

AbstractCurrent opinion holds that pores in synthetic nerve guides facilitate nerve regeneration. Solid factual support for this opinion, however, is absent; most of the relevant studies assessed only morphological parameters and results have been contradictory. To evaluate the effect of pores, the rat sciatic nerve was either autografted or grafted with nonporous, macroporous (10–230 μm), and microporous (1–10 μm) biodegradable ε‐caprolactone grafts. Twelve weeks later, the grafted nerves were resected, and the electrophysiological properties were determined in vitro. Subsequently midgraft‐level sections were inspected, and peroneal nerve sections were evaluated morphometrically. Finally, the gastrocnemic and tibial muscle morphometrical properties were quantified. The microporous nerve graft performed much better than the nonporous and macroporous grafts with respect to most parameters: it was bridged by a free floating bundle that contained myelinated nerve fibers, there were more nerve fibers present distal to the graft, the electrophysiological response rate was higher, and the decrease in muscle cross‐sectional area was markedly smaller. Hence, the present study demonstrates the beneficial effect of synthetic nerve guide pores on nerve regeneration, although with the caveat that not pores per se, but only small (1–10 μm) pores were effective. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006