Optimizing Router Performance in TCP/IP Networks

This article reviews the steps necessary to configure and implement a complex router internetwork. This article will specifically concentrate on Cisco routers, and since they support Transmission Control Protocol/Internet Protocol (TCP/IP) natively, it will concentrate on a backbone network employing that protocol.     

Analysis of the effect of shrinkage on macrosegregation in alloy solidification

Numerical calculations based on a continuum model are used to examine the effects of solidification shrinkage on the redistribution of solute in a Pb-19.2 pct Sn mixture which is convectively cooled at a sidewall. For each of three different cooling rates, separate calculations are performed for shrinkage and buoyancy-induced flows, as well as for the combined influence of shrinkage and buoyancy effects. The calculations reveal that flow and macrosegregation patterns are more strongly influenced by buoyancy effects over a wide range of solidification rates. Although extremely large solidification rates yield small regions near the chilled wall in which shrinkage-induced flows control the redis-tribution of solute, the overall effect on macrosegregation is small relative to that associated with buoyancy. Scaling analysis of the governing equations produces reference shrinkage and buoyancy velocities which can be used to extend the current numerical results to other binary systems.     

New and used temporal models: An issue of time

TheSpecial Issue on Applications of Temporal Models raises many issues of time: What are the important properties of time? How can time be best represented? How can one reason about time-dependent properties? What are the important directions of temporal research? This introductory piece very briefly surveys the current wide variety of temporal models, temporal reasoning methods, and applications to time-varying phenomena. Promising areas of investigation such as the verification of concurrent systems, knowledge-base representation methods, and dealing with theFrame Problem pass in fleeting review. Brief introductions to each of the works in the volume close the section.     

Extending the Kernighan/Lin Heuristic for Hardware and Software Functional Partitioning

The Kernighan/Lin graph partitioning heuristic, also known as min-cut or group migration, has been extended over several decades very successfully for circuit partitioning. Those extensions customized the heuristic and its associated data structure to rapidly compute the minimum-cut metric central to circuit partitioning; as such, those extensions are not directly applicable to other problems. In this paper, we extend the heuristic for functional partitioning, which in turn can solve the much investigated codesign problem of partitioning a system's coarse-grained functions among hardware and software components. The key extension customizes the heuristic and data structure to rapidly compute execution-time and communication metrics, crucial to hardware and software partitioning, and leads to near-linear time-complexity and excellent resulting quality. Another extension uses a new criteria for terminating the heuristic, eliminating time-consuming and unnecessary fine-tuning of a partition. Our experiments demonstrate extremely fast execution times (just a few seconds) with results matched only by the slower simulated annealing heuristic, meaning that the extended Kernighan/Lin heuristic will likely prove hard to beat for hardware and software functional partitioning.     

Estimates of the dollar value of employee output in utility analyses: An empirical test of two theories.

Examined distributions of estimates of the dollar value of performance in studies employing the method of F. L. Schmidt et al (1979) for estimating the standard deviation of job performance (SDy) and found evidence that (1) the mean 50th percentile estimate is biased downward, (2) estimates of SDy appear to be a constant percentage of the 50th percentile estimate, and (3) estimates of SDy as a percentage of the 50th percentile value (SDp) are quite similar to empirical SDp values based on actual employee output. These findings suggest that the downward bias in the mean estimate of the 50th percentile causes the mean estimates of SDy to be similarly biased downward, but does not bias the estimates of SDp. Finally, an objective method for estimating the value of average employee output is described. The product of this value and the mean supervisory estimate of SDp yields an unbiased estimate of SDy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Zur Modellierung von Sauterdurchmesser und Hold-up beim Einsatz eines konischen Turbinenrührers zum Dispergieren gas-flüssig

By comparing the experimental data of the Sauter-mean-diameter d ₃₂ and the hold up ? with models from literature, there are presented equations for d ₃₂ and ? for the used conical turbine in gas-liquid systems. The necessary adjustment of the proportionality constants of the literature equations will be explained on the basis of fluiddynamical phenomena. It can be established by fluid-dynamical results of a former study carried out with laser-doppler-anemometry. Coalescence phenomena are taken into account in the model using an analogy to bubble columns. The analogy to bubble columns turns out to be suitable. Arguments for the necessity of considering the local fluiddynamics in the modelling of dispersions are presented.     

On-line coupled liquid chromatography-gas chromatography (LC-GC) and LC-LC-GC for detecting irradiation of fat-containing foods

Summary On-line coupled liquid chromatography-gas chromatography-flame ionisation detection (LC-GC-FID) enables efficient and unambiguous determination of irradiation for some fat-containing foods (e.g. meat). Other products, however, contain interfering components or are contaminated, e.g., with mineral oil. Since more selective detection by mass spectrometry has limited success, the determination was improved by a more selective isolation of some key components among the fat degradation products, e.g. the dienes or trienes, by LC-LC-GC-FID. Applications are shown for soup mixes, some spices, fish, and shrimps.

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Nachweis der Bestrahlung fetthaltiger Lebensmittel durch direkt gekoppelte LC-GC und LC-LC-GC

Zusammenfassung Die Bestrahlung einiger fetthaltiger Lebensmittel, z. B. Fleisch, kann mit direkt gekoppelter LC-GC-FID rationell und eindeutig nachgewiesen werden. In anderen Proben wird die Analyse aber durch Inhaltsstoffe des Produktes oder durch Verunreinigungen (z. B. mit Mineralöl) gestört. Da selektivere Detektion durch Massenspektrqmetrie wenig verspricht, wurde der Nachweis durch selektivere Isolierung von Schlüsselkomponenten unter den Bestrahlungsprodukten, z. B. der Diene oder Triene, mittels LC-LC-GC yerbessert. Anwendungen werden gezeigt für Suppenpulver, einige Gewürze, Fisch und Garnelen.

     

Specific heat of amorphous3He films and confined liquid3He

We have measured the heat capacities of³He films and liquid³He in porous Vycor glass at 10 to 600 mK. With increasing the film thickness from 1 to 3 atomic layers, the specific heat evolves gradually from that typical to solid to that of liquid³He. At about 2 atomic layers, however, its low-temperature part is nearly temperature-independent; we interpret this as a result of gradual freezing of spins in an amorphous solid³He film with decreasing the temperature. The contribution of liquid³He in the center of the Vycor pores can be described as the specific heat of bulk liquid³He at corresponding pressures in the range 0 to 28 bar. The thickness of amorphous solid on the pore walls increases with external pressure roughly linearly. Preplating the walls with⁴He allows to determine the positions of³He atoms contributing to the surface specific heat at 10 to 50 mK. In addition, the contribution from the specific heat of³ He -⁴He mixing at 100 to 600 mK is discussed as a function of pressure and amount of⁴He.0n leave from ISSP Acad. Sci. of Russia, Chernogolovka, Russia