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Efficient Communication (efficient + communication)

Distribution by Scientific Domains

Life Sciences	40%

Selected Abstracts

Efficient communication using message prediction for clusters of multiprocessors

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 10 2002
Ahmad Afsahi
Abstract With the increasing uniprocessor and symmetric multiprocessor computational power available today, interprocessor communication has become an important factor that limits the performance of clusters of workstations/multiprocessors. Many factors including communication hardware overhead, communication software overhead, and the user environment overhead (multithreading, multiuser) affect the performance of the communication subsystems in such systems. A significant portion of the software communication overhead belongs to a number of message copying operations. Ideally, it is desirable to have a true zero-copy protocol where the message is moved directly from the send buffer in its user space to the receive buffer in the destination without any intermediate buffering. However, due to the fact that message-passing applications at the send side do not know the final receive buffer addresses, early arrival messages have to be buffered at a temporary area. In this paper, we show that there is a message reception communication locality in message-passing applications. We have utilized this communication locality and devised different message predictors at the receiver sides of communications. In essence, these message predictors can be efficiently used to drain the network and cache the incoming messages even if the corresponding receive calls have not yet been posted. The performance of these predictors, in terms of hit ratio, on some parallel applications are quite promising and suggest that prediction has the potential to eliminate most of the remaining message copies. We also show that the proposed predictors do not have sensitivity to the starting message reception call, and that they perform better than (or at least equal to) our previously proposed predictors. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Efficient communication in unknown networks

NETWORKS: AN INTERNATIONAL JOURNAL, Issue 1 2001
Luisa Gargano
Abstract We consider the problem of disseminating messages in networks. We are interested in information dissemination algorithms in which machines operate independently without any knowledge of the network topology or size. Three communication tasks of increasing difficulty are studied. In blind broadcasting (BB), the goal is to communicate the source message to all nodes. In acknowledged blind broadcasting (ABB), the goal is to achieve BB and inform the source about it. Finally, in full synchronization (FS), all nodes must simultaneously enter the state terminated after receiving the source message. The algorithms should be efficient both in terms of the time required and the communication overhead they put on the network. We limit the latter by allowing every node to send a message to at most one neighbor in each round. We show that BB is achieved in time at most 2n in any n -node network and show networks in which time 2n , o(n) is needed. For ABB, we show algorithms working in time (2 + ,)n, for any fixed positive constant , and sufficiently large n. Thus, for both BB and ABB, our algorithms are close to optimal. Finally, we show a simple algorithm for FS working in time 3n and a more complicated algorithm which works in time 2.9n. The optimal time of full synchronization remains an open problem. © 2001 John Wiley & Sons, Inc. [source]

Signalling pathways in the pathogenesis of Cryptococcus

CELLULAR MICROBIOLOGY, Issue 3 2009
Lukasz Kozubowski
Summary Efficient communication with the environment is critical for all living organisms. Fungi utilize complex signalling systems to sense their environments and control proliferation, development and in some cases virulence. Well-studied signalling pathways include the protein kinase A/cyclic AMP (cAMP), protein kinase C (PKC)/mitogen-activated protein kinase (MAPK), lipid signalling cascades, and the calcium,calcineurin signalling pathway. The human pathogenic basidiomycetous fungus Cryptococcus neoformans deploys sensitive signalling systems to survive in the human host, leading to life-threatening meningoencephalitis. Known virulence traits of this fungus, including the antioxidant melanin production, the antiphagocytic polysaccharide capsule and the ability to grow at 37°C, are orchestrated by complex signalling networks, whose understanding is crucial to better treat, diagnose and prevent cryptococcosis. [source]

Attention , oscillations and neuropharmacology

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2009
Gustavo Deco
Abstract Attention is a rich psychological and neurobiological construct that influences almost all aspects of cognitive behaviour. It enables enhanced processing of behaviourally relevant stimuli at the expense of irrelevant stimuli. At the cellular level, rhythmic synchronization at local and long-range spatial scales complements the attention-induced firing rate changes of neurons. The former is hypothesized to enable efficient communication between neuronal ensembles tuned to spatial and featural aspects of the attended stimulus. Recent modelling studies suggest that the rhythmic synchronization in the gamma range may be mediated by a fine balance between N -methyl- d -aspartate and ,-amino-3-hydroxy-5-methylisoxazole-4-propionate postsynaptic currents, whereas other studies have highlighted the possible contribution of the neuromodulator acetylcholine. This review summarizes some recent modelling and experimental studies investigating mechanisms of attention in sensory areas and discusses possibilities of how glutamatergic and cholinergic systems could contribute to increased processing abilities at the cellular and network level during states of top-down attention. [source]

Faculty-development activity to promote effective communication between instructors and students

THE CLINICAL TEACHER, Issue 2 2010
Netta Notzer
Summary Background:, Educators claim that conflicts and teacher,student miscommunications interfere in achieving optimal learning outcomes. Context:, Conflicts arise when clinical instructors communicate in a patronising fashion, expressing values that are not those of their medical students. This paper presents our approach of coping with such conflicts. It is based on the notion that language is comprised of developmental levels. The objective is to switch the instructor's lower level of language from an uncontrolled reaction to a high level of efficient communication. Innovation:, During our faculty-development workshops, we piloted sessions consisting of vignettes depicting instructor,student conflicts. The workshop participants were asked to react and discuss questions on their feelings in similar conflicts, and their immediate speech reaction to students. The workshop's facilitator pointed out that there was no one right solution. She singled out the reaction that takes into account the student's personality, avoiding imposing solutions. The feedback on these sessions was very favourable, indicating a high level of satisfaction. Implications:, The positive feedback is very encouraging. We believe that our workshops amplify the desired effective instructor,student communication, and suggest that the success of this intervention is partly achieved by selecting problematic issues of communication, and adjusting them to the current needs of our faculty members. In order to reproduce our approach, we suggest that other institutions should define their own values and communication code. We recommend them to use the same technique of intervention among a small group in an empowering atmosphere of discussion, using their own situations. [source]