We present in this paper a general garbage collection scheme that reduces the "noise" in gossip-based broadcast algorithms. In short, our garbage collection scheme uses a simple heuristic to trade "usel...
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We present in this paper a general garbage collection scheme that reduces the "noise" in gossip-based broadcast algorithms. In short, our garbage collection scheme uses a simple heuristic to trade "useless" messages with "useful" ones. Used with a given gossip-based broadcast algorithm, a given size of buffers, and a given number of disseminated messages (e.g., per gossip round), our garbage collection scheme provides higher overall reliability than more conventional schemes. We illustrate our approach through two algorithms: bimodal multicast (pbcast) and lightweight probabilistic broadcast (lpbcast). Our scheme is based on the intuitive idea of discarding messages according to their "age". The "age" of a message represents the number of times the message has been retransmitted.
Over the past decade,the power conversion efficiency of halide perovskite solar cells has shown a rapid increase to 26.1%.The significant efficiency growth and the relative simplification of the technology for o...
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Over the past decade,the power conversion efficiency of halide perovskite solar cells has shown a rapid increase to 26.1%.The significant efficiency growth and the relative simplification of the technology for obtaining thin-film solar cells due to liquid printing methods determine the high potential for the low-cost perovskite solar cells ***,efficient use of cell geometry is comparable to the size of standard crystalline-Si wafers(156:156 mm and more).Therefore,modular geometry similar to amorphous-Si solar cell approaches is used to scale perovskite solar *** electrical connection of thin-film cells requires precise processing of the conductive layers that form the device p-i-n *** subject of research is the development of a full pulsed laser scribing cycle for inverted perovskite solar *** this work,we propose a study of a laser-patterning technology In_(2)O_(3):SnO_(2)(ITO)conductive layer and a photoactive perovskite layer Cs0,2(CH(NH_(2))_(2))_(0,8)PbI_(3).Process regimes of transparent conducting electrodes based on ITO and halide perovskite layer Cs_(0,2)(CH(NH_(2))_(2))_(0,8)PbI_(3)laser patterning were *** optimal parameters for the multipass mode processing of ITO and perovskite layer were *** cell was electrically isolated at a scribe line width of 30μm.
The effects of maternal treatment with dexamethasone during lactation on pubertal timing, serum hormonal profile and sperm indices in the male offspring were assessed. Twenty lactating dams were divided into 4 groups ...
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Through a detailed analysis of the theoretical basis for MOOCs in terms of educational learning theories, this paper attempts at finding the corresponding relationship between the theories and MOOCs, which not only th...
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ISBN:
(纸本)9789881925367
Through a detailed analysis of the theoretical basis for MOOCs in terms of educational learning theories, this paper attempts at finding the corresponding relationship between the theories and MOOCs, which not only theoretically explains the reasons why MOOCs exceed all the previous education models, but also empirically proves it with voluminous facts and data. The author conducts this research in the hope of enlightening the online education platform of other types. Besides, this paper provides the model framework and strategy to multidimensional educational review based on MOOCs. The model and strategy are applicable not only to MOOCs, the large-scale online education, but also to various online education platforms.
We examine the non-Markovian nature of human mobility by exposing the inability of Markov models to capture criticality in human mobility. In particular, the assumed Markovian nature of mobility was used to establish ...
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Leveraged by the success of applications aiming at the "free" sharing of data in the Internet, the paradigm of peer-to-peer (P2P) computing has been devoted substantial consideration recently. This paper pre...
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ISBN:
(纸本)9781581135992
Leveraged by the success of applications aiming at the "free" sharing of data in the Internet, the paradigm of peer-to-peer (P2P) computing has been devoted substantial consideration recently. This paper presents an abstraction for remote object interaction in a P2P environment, called borrow/lend (BL). We present the principles underlying our BL abstraction, and its implementation in Java. We contrast our abstraction with established abstractions for distributed programming such as the remote method invocation or the tuple space, illustrating how the BL abstraction, obviously influenced by such predating abstractions, unifies flavors of these, but also how it captures the constraints specific to P2P environments.
For a generic loop: while (constraints) {updates} it is well known that the termination problem is undecidable in general, even for a simple class of polynomial programs. If the constraints or the updating function in...
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For a generic loop: while (constraints) {updates} it is well known that the termination problem is undecidable in general, even for a simple class of polynomial programs. If the constraints or the updating function in the above loop is not linear, the loop is called nonlinear. In this paper, we investigate how to solve the termination of the above loop by deciding whether a fixed point exists, when the constraints are the union of intervals and the updating functions are polynomials. Furthermore, when all fixed points are on the boundaries of the union of intervals, we also establish a corresponding necessary and sufficient condition of nontermination.
We address the problem of performing a pipelined broadcast on a mesh architecture. Meshes require a different approach than other topologies, and their very nature puts a tighter bound on the performance that one can ...
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We address the problem of performing a pipelined broadcast on a mesh architecture. Meshes require a different approach than other topologies, and their very nature puts a tighter bound on the performance that one can hope to achieve. By using the appropriate techniques, however, one can obtain excellent performance for sufficiently long messages. The resulting algorithm will work on meshes of any dimension with any number of nodes. Our model assumes that the mesh is a torus and/or that it has bidirectional links and uses wormhole routing. Performance data from the Cray T3D are included.
Publish/subscribe (pub/sub) is considered a valuable middleware architecture that proliferates loose coupling and leverages reconfigurability and evolution. Up to now, existing pub/sub middleware was optimized for sta...
ISBN:
(纸本)9783540403173
Publish/subscribe (pub/sub) is considered a valuable middleware architecture that proliferates loose coupling and leverages reconfigurability and evolution. Up to now, existing pub/sub middleware was optimized for static systems where users as well as the underlying system structure were rather fixed. We study the question whether existing pub/sub middleware can be extended to support mobile and location-dependent applications. We first analyze the requirements of such applications and distinguish two orthogonal forms of mobility: the system-centric physical mobility and an application-centric logical mobility (where users are aware that they are changing location). We introduce location-dependent subscriptions as a suitable means to exploit the power of the event-based paradigm in mobile applications. Briefly spoken, location-dependency refines a subscription to accept only events related to a mobile user's current location. Implementations for both forms of mobility are presented within the content-based pub/sub middleware Rebeca, drawing from its refined routing capabilities (namely, covering and merging).
Bioinformatics applications constitute an emerging data-intensive, high-performance computing (HPC) domain. While there is much research on algorithmic improvements, (2004), the actual performance of an application al...
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Bioinformatics applications constitute an emerging data-intensive, high-performance computing (HPC) domain. While there is much research on algorithmic improvements, (2004), the actual performance of an application also depends on how well the program maps to the target hardware. This paper presents a performance study of two parallel bioinformatics applications HMMER (sequence alignment) and SVM-RFE (gene expression analysis), on Intel x86 based hyperthread-capable (2002) shared-memory multiprocessor systems. The performance characteristics varied according to the application and target hardware characteristics. For instance, HMMER is compute intensive and showed better scalability on a 3.0 GHz system versus a 2.2 GHz system. However, SVM-RFE is memory intensive and showed better absolute performance on the 2.2 GHz machine which has better memory bandwidth. The performance is also impacted by processor features, e.g. hyperthreading (HT) (2002) and prefetching. With HMMER we could obtain -75% of the performance with HT enabled with respect to doubling the number of CPUs. While load balancing optimizations can provide speedup of -30% for HMMER on a hyperthreading-enabled system, the load balancing has to adapt to the target number of processors and threads. SVM-RFE benefits differently from the same load-balancing and thread scheduling tuning. We conclude that compiler and runtime optimizations play an important role to achieve the best performance for a given bioinformatics algorithm.
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