On collaborative content distribution using multi-message gossip

We study epidemic schemes in the context of collaborative data delivery. In this context, multiple chunks of data reside at different nodes, and the challenge is to simultaneously deliver all chunks to all nodes.     

Assessing pre- and post-deformation in the southern Arava Valley segment of the Dead Sea Transform, Israel by differential interferometry

Differential radar interferometry, using archived ERS data over the region of the Dead Sea Transform, allows to detect ground movement (subsidence or uplift) in playas within the southern Arava Valley segment of the Dead Sea Rift. These measurements are consistent with a mean displacement rate of about 0.4 cm/month, in the direction of the radar beam, during the 8-month period preceding the Nuweiba earthquake of 22 November 1995. In the 3 years following the earthquake, the measured rate was smaller by a factor of 10. These movements are not related to salt diapirs or water pumping activities in the area. The exact location, along faults, suggests a possible correlation with pre-seismic and post-seismic fault deformation.A simple fault model consistent with the observed phenomena associates the observed subsidence/uplift to right and left stepping en-echelon fault patterns related to inter-seismic tensional accumulation along the faults. Further observations are necessary on this site and similar fault areas to corroborate the correlation between seismic activity and the observed phenomena. Monitoring of these sites should continue with differential Global positioning system (GPS) measurements and radar interferometric analysis using Envisat and Radarsat as well as archived data (including J-ERS).     

Automatic processing of psychological distance: Evidence from a Stroop task.

A picture-word version of the Stroop task was used to test the automatic activation of psychological distance by words carrying various senses of psychological distance: temporal (tomorrow, in a year), social (friend, enemy), and hypotheticality (sure, maybe). The pictures implied depth, with the words appearing relatively close to or distant from the observer. The participants classified the spatial distance of words faster when the word's implicit psychological distance matched its spatial distance (e.g., a geographically close word was classified faster when it was "friend" than when it was "enemy"). The findings are consistent with the idea that psychological distance is accessed automatically, even when it is not directly related to people's current goals, and suggest that psychological distance is an important dimension of meaning, common to spatial distance, temporal distance, social distance, and hypotheticality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A mixed-mode fracture specimen: analysis and testing

A mixed-mode fracture specimen which is employed to measure K _I and K _II failure values for 0K _I /K _II 0.28 is analyzed. In order to perform experiments, specimen calibration formulas relating K _I and K _II to the applied load and specimen geometric parameters must be obtained.To this end, a mixed-mode weight function method is applied to the specimen, requiring the stress intensity factors and displacement fields induced by two different loading cases. These quantities are determined by means of a finite element analysis which makes use of a singular crack tip element. For this range of K ratio, the stress field in the central region of the specimen before crack introduction is nearly uniform; hence, expressions for the desired mixed-mode stress intensity factors may be written as the product of two factors; one depending upon crack length and one depending upon loading angle.Once the K calibration formulas are obtained as a function of applied load and specimen geometry, testing may be carried out. Here, perspex specimens are tested; results for K _I , K _II and crack propagation angle at fracture compare reasonably well with failure curves determined from an extended maximum tangential stress criterion.

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Résumé On analyse le cas d'une éprouvette présentant une rupture de mode mixte en vue de mesurer les valeurs à la rupture de K _I et K _II , le rapport K ₁ /K ₂ étant compris entre 0 et 0,28. Pour réaliser l'expérience, il y a lieu d'établir les formules d'étalonnage mettant en relation K _I et K _II avec la charge appliquée et les paramètres géométriques de l'éprouvette.A cette fin, on applique à l'éprouvette une méthode de fonction pondérée de mode mixte, requérant les valeurs des facteurs d'intensité de contraintes et les champs de déplacement induits par deux cas de mise en charge différents.Ces quantités sont déterminées grâce à une analyse par éléments finis utilisant un élément singulier à l'extrémité de la fissure.Pour les rapports de K ci-dessus, le champ de contraintes dans la région centrale de l'éprouvette avant introduction de la fissure est sensiblement uniforme. On peut, dès lors, écrire les expressions des facteurs d'intensité de contrainte correspondant au mode mixte désiré sous forme d'une produit de deux facteurs: l'un dépend de la longueur de fissure et l'autre de l'angle de mise en charge.L'essai peut être exécuté une fois obtenues les formules d'étalonnage de K en fonction de la charge appliquée et de la géométrie de l'éprouvette. On utilise dans le cas présent des éprouvettes en perspex, et les résultats pour K _I , K _II et l'angle de propagation de la fissure lors de la rupture concordent assez bien avec les courbes de rupture déterminée à partir d'une critère élargi de la tension tangentielle maximale.

     

The microstructure and infra-red spectra of hydrated tricalcium silicate containing phosphate

The influence of phosphate, in the concentration range 0.7 to 4.5%, on the hydration reaction of tricalcium silicate was examined with a scanning electron microscope and an infra-red spectrometer. Correlation between the morphology and infra-red vibrations, on the one hand, and the free lime content dependence on the phosphate concentration, on the other, is discussed.This paper is in partial fulfilment of the MSc degree of Y. Rubinsztain, at the Hebrew University.     

Determinants of perceived social support: Interpersonal transactions, personal outlook, and transient affective states.

During the last decade, the study of social support has relied heavily on recipients' reports of perceived support. However, such reports of support may reflect not only actual supportive interpersonal transactions but also the recipients' own personal and perceptual dispositions and comparatively transient mood states. This study examines these factors' independent effects on perceived support. Interpersonal transactions of social support were assessed in a longitudinal panel design using reports from 486 adult male respondents and their significant others (mostly wives). Using structural modeling techniques ({lisrel vi}), an unfolding series of statistical analyses were performed. The results provide strong support for a model in which recipients' perception of support is determined significantly and strongly by actual interpersonal transactions as reported by significant others, moderately by the recipients' negative outlook bias, and weakly by their anxiety and depression as indicators of their poor mental health. The implications of the results for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Counteractive self-control in overcoming temptation.

How do anticipated short-term costs affect the likelihood of engaging in an activity that has long-term benefits. Five studies investigated the factors that determine (a) how anticipated short-term costs elicit self-control efforts and (b) how self-control efforts eventually diminish the influence of short-term costs on behavior. The studies manipulated short-term costs (e.g., painful medical procedures) and assessed a variety of self-control strategies (e.g., self-imposed penalties for failure to undergo a test). The results show that short-term costs elicit self-control strategies for self rather than others, before rather than after behavior, when long-term benefits are important rather than unimportant and when the costs are moderate rather than extremely small or large. The results also show that the self-control efforts help people act according to their long-term interests. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Time-dependent gambling: Odds now, money later.

Four experiments investigated temporal changes in the influence of probability and payoffs on gambling. Using urn draws, the authors found in Experiment 1 that temporal distance increased the influence of payoffs and decreased the influence of probability on preferences. The authors found in Experiment 2 that in choosing among the more distant gambles, participants offered more reasons dealing with payoffs and fewer reasons dealing with probability. In Experiments 3 and 4, the authors extended the scope of these findings using a card game and a raffle. The results were interpreted in terms of a temporal construal process that highlights the desirability of outcomes in the distant future and the feasibility of attaining the outcomes in the near future. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Efficient parallel algorithms forr-dominating set andp-center problems on trees

We develop efficient parallel algorithms for ther-dominating set and thep-center problems on trees. On a concurrent-read exclusive-write PRAM, our algorithm for ther-dominating set problem runs inO(logn log logn) time withn processors. The algorithm for thep-center problem runs inO(log² n log logn) time withn processors.Xin He was supported in part by an Ohio State University Presidential Fellowship, and by the Office of Research and Graduate Studies of Ohio State University. Yaacov Yesha was supported in part by the National Science Foundation under Grant No. DCR-8606366.     

Temporal construal.

Construal level theory proposes that temporal distance changes people's responses to future events by changing the way people mentally represent those events. The greater the temporal distance, the more likely are events to be represented in terms of a few abstract features that convey the perceived essence of the events (high-level construals) rather than in terms of more concrete and incidental details of the events (low-level construals). The informational and evaluative implications of high-level construals, compared with those of low-level construals, should therefore have more impact on responses to distant-future events than near-future events. This article explores the implications of construal level theory for temporal changes in evaluation, prediction, and choice. The authors suggest that construal level underlies a broad range of evaluative and behavioral consequences of psychological distance from events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)