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131.
Distributed match-making 总被引:1,自引:0,他引:1
In many distributed computing environments, processes are concurrently executed by nodes in a store- and-forward communication network. Distributed control issues as diverse as name server, mutual exclusion, and replicated data management involve making matches between such processes. We propose a formal problem called distributed match-making as the generic paradigm. Algorithms for distributed match-making are developed and the complexity is investigated in terms of messages and in terms of storage needed. Lower bounds on the complexity of distributed match-making are established. Optimal algorithms, or nearly optimal algorithms, are given for particular network topologies.The work of the second author was supported in part by the Office of Naval Research under Contract N00014-85-K-0168, by the Office of Army Research under Contract DAAG29-84-K-0058, by the National Science Foundation under Grant DCR-83-02391, and by the Defence Advanced Research Projects Agency (DARPA) under Contract N00014-83-K-0125. Current address of both authors: CWI, Kruislaan 413, 1098 SJ Amsterdam, The Netherlands. 相似文献
132.
Werner Strohmaier Henning Klostermeyer Paul Deuritz Erich Windhab 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1992,194(6):531-535
Summary Current texture-measuring instruments and a recently developed measuring method (two-dimensional measuring of the force necessary to spread a sample) were compared in measuring the spreadability of processed cheese. How far subjective assessment by a qualified panel correlates with the instrumental results in determining spreadability and firmness was also investigated. Samples of processed cheese with various consistencies were measured by an Universal testing machine, a buttermeasuring instrument (DIN 10331), a rotational-type rheometer (oscillation mode) and a two-dimensional force measuring instrument. The evaluation of the results shows that an oscillating rheometer is most suitable to measure the spreadability of processed cheese; the correlation coefficient (r) between the dynamic Weissenberg number, calculated from parameters of the rheometer, and the subjective judgement by the panel wasr=0.91. For the determination of firmness the two-dimensional force measuring instrument is most suitable. The correlation coefficient between the parameter tangential energy (S
t) and the sensorially evaluated firmness wasr=0.95.
Vergleich verschiedener Bestimmungsmethoden für die Streichfähigkeit und Festigkeit von Schmelzkäse
Zusammenfassung Verschiedene gebräuchliche Meßinstrumente und ein neu entwickeltes Gerät zur zweidimensionalen Messung der Kräfte, die zum Ausstreichen einer Probe erforderlich sind, wurden vergleichend zur Charakterisierung der Streichfähigkeit von Schmelzkäse erprobt. Dabei wurde auch geprüft, inwieweit die subjektiven Beurteilungen eines qualifizierten Prüferpanels mit den Meßwerten für Streichfähigkeit und Festigkeit korrelierten. Gemessen wurde mit einer Universalprüfmaschine, dem Butterprüfgerät (DIN 10331), einem Rotationsrheometer und mit dem zweidimensional registrierenden Kraftmeßgerät. Dabei zeigte sich, daß das Rheometer im oscillierenden Modus die Streichfähigkeit am besten zu charakterisieren vermag. Die Korrelation zwischen den Rheometerwerten, berechnet als dynamische Weissenbergzahl, und den sensorisch ermittelten Werten für die Streichfähigkeit betrugr=0,91. Zur Bestimmung der Festigkeit ist das zweidimensional registrierende Kraftmeßgerät am besten geeignet, was sich in einem Korrelationskoeffizienten vonr=0,95 zwischen dem ParameterS t und den im Sensoriktest ermittelten Werten für dieFestigkeit ausdrückt.相似文献
133.
A revolution is coming--is absolutely essential--in healthcare. The chief information officer must be among the generals who plan battle strategies and lead the campaigns to fight inflating costs and overwhelming demands. Without their leadership and expertise, armies of healthcare providers are destined to fail, and legions of citizens will fall victim to a system inadequate to meet their needs. 相似文献
134.
Paul Feautrier 《International journal of parallel programming》1992,21(6):389-420
This paper extends the algorithms which were developed in Part I to cases in which there is no affine schedule, i.e. to problems whose parallel complexity is polynomial but not linear. The natural generalization is to multidimensional schedules with lexicographic ordering as temporal succession. Multidimensional affine schedules, are, in a sense, equivalent to polynomial schedules, and are much easier to handle automatically. Furthermore, there is a strong connection between multidimensional schedules and loop nests, which allows one to prove that a static control program always has a multidimensional schedule. Roughly, a larger dimension indicates less parallelism. In the algorithm which is presented here, this dimension is computed dynamically, and is just sufficient for scheduling the source program. The algorithm lends itself to a divide and conquer strategy. The paper gives some experimental evidence for the applicability, performances and limitations of the algorithm. 相似文献
135.
Paul F. Becher 《Journal of Materials Science》1986,21(1):297-300
The room temperature slow crack growth resistance in air ( 50% relative humidity) and in water for large cracks in MgO-partially stabilized zircoba (PSZ) improves with increase in critical fracture toughness,K
lc. Ageing the as-fired PSZ at 1400° C for 8 h results in decreasing Klc from 8.5 MPa m1/2 to 6 M Pa M1/2. The ageing treatment also promotes the growth of eutectoid decomposition products on grain boundaries that is accompanied by a decrease in the dependence (A the change in Region I crack velocity with a change in the applied stress intensity. Calculated times to failures are markedly decreased in the aged as compared to the as-fired PSZ ceramic. 相似文献
136.
The tokamak and tandem mirror concepts are compared with alternate confinement concepts using the criteria established in DOE/ET-0047, An Evaluation of Alternate Magnetic Fusion Concepts 1977. The concepts are evaluated and rated in each of three broad categories: confidence in physics and technology, and reactor desirability. The STARFIRE and MARS reactors are used as a basis for comparing the mainline tokamak and tandem mirror concepts with the alternate concepts evaluated in DOE/ET-0047. Two recent alternate concepts, theohmically heated toroidal experiment (OHTE) and thecompact reversed field pinch reactor (CRFPR), are also evaluated. Results indicate that the physics of the mainline tokamaks and tandem mirrors is better understood than that of most alternate concepts. Both mainline concepts rank near the middle for technology requirements, and both rank near or at the bottom when compared with the reactor desirability of alternate concepts. 相似文献
137.
Paul E. Dunne 《Acta Informatica》1985,22(2):229-240
Summary The k-th threshold function, T
k
n
, is defined as:
where x
i{0,1} and the summation is arithmetic. We prove that any monotone network computing T
3/n(x
1,...,x
n) contains at least 2.5n-5.5 gates.This research was supported by the Science and Engineering Research Council of Great Britain, UK 相似文献
138.
Oxyfluorophosphate glasses containing about 80 mol% of [LiF+Li2O] show unusually high lithium ion conductivity at elevated temperatures. A detailed investigation has been carried out on the glasses prepared by both conventional cooling and a rapid quenching technique. Chemical analysis of the glasses reveals fluorine loss during melting and it becomes difficult to make glasses with exact predetermined compositions. Electrical conductivity of the glasses, determined from complex impedance analysis increases with Li2O content. A glass with nominal composition 70 LiF15 Li2O15 Al(PO3)3 shows the highest conductivity (~ 1.3×10–3 ohm–1 cm–1 around 200° C) among all the compositions studied. An interesting feature of the impedance plot is the near perfect semicircle for bulk relaxation indicating a narrow distribution of relaxation times. This has been explained on the basis of a relatively small proportion of lithium ions which are mobile. The electrical conductivity of the glasses is found to be essentailly independent of dissolved water content. The infrared spectra of these glasses (2 to 50m region) could not produce much useful structural information. 相似文献
139.
Theoretical Models for Binder Burnout 总被引:8,自引:0,他引:8
The kinetics of binder burnout, from a ceramic green body, are considered for the case of an "unzipping" binder which decomposes to produce a volatile monomer. The process is considered to fail if the concentration of monomer in the green body exceeds that in equilibrium with vapor at 1 atm (≅105 Pa), when an internal bubble would be expected to form. Steady-state diffusional calculations and computer simulations explore the size and temperature dependence of the process and are in agreement. The model suggests that it is not feasible to burn out a large flat piece greater than about 3 mm thick, without going to very long times of burnout. The kinetics are significantly improved if porosity develops in the piece during the early stages of decomposition, as opposed to the retreat of the binder into the piece on a uniform front. 相似文献
140.