A radial sine phase filter is introduced in optical systems to control and alter the optical system focusing properties with incident Gaussian beam. It was found that the radial sine phase filter can induce tunable mu...
详细信息
Broadcasting is an information dissemination problem in a connected network, in which one node, called the originator, disseminates a message to all other nodes by placing a series of calls along the communication lin...
详细信息
Broadcasting is an information dissemination problem in a connected network, in which one node, called the originator, disseminates a message to all other nodes by placing a series of calls along the communication lines of the network. Once informed, the nodes aid the originator in distributing the message. Finding the minimum broadcast time of a vertex in an arbitrary graph is NP-complete. The problem is solved polynomially only for trees, unicyclic graphs, and tree of cycles. In this paper we consider broadcasting in a new class called the Fully Connected Trees (FCT). We present a O(n log n) algorithm to find the broadcast time of any originator in an arbitrary FCT.
The wide increase of total processing cores in commodity processors tends to lighten the need for computer performance by the classical scientific problems as well as by the modern multimedia and every day embedded ap...
详细信息
The wide increase of total processing cores in commodity processors tends to lighten the need for computer performance by the classical scientific problems as well as by the modern multimedia and every day embedded applications. Nevertheless, the introduction of this powerful and promising technology seems to inherit and in some cases magnify all the classical problems that already exist on the programming side of these environments. In this work we present a portable environment based on the Java platform targeting to mitigate the performance loss associated with the programming models used in modern multicore systems. We propose a shared memory model for programming modern multicore and distributed environments, presuming only minor interventions by the application programmer. We finally prove that when we use shared memory programming with a widely accepted programming language like Java, we can achieve at least comparable performance with classical though more sophisticated technologies.
In recent years, many routing protocols for wireless sensor networks (WSNs) have been designed to achieve high energy-efficiency, high reliability, low overhead, etc. However, few routing protocols for WSNs were desig...
详细信息
In recent years, many routing protocols for wireless sensor networks (WSNs) have been designed to achieve high energy-efficiency, high reliability, low overhead, etc. However, few routing protocols for WSNs were designed to minimize the communication delay, which is one of the most important requirements for applications of WSNs, such as real-time surveillance systems. In this paper, a novel real-time routing protocol for WSNs is proposed for guaranteeing real-time communication. Additionally, energy-efficiency that prolongs the network lifetime is fully considered. Performance analyses and simulation results show that our protocol has much better performance than Directed Diffusion and Rumor Routing in terms of both communication delay and network lifetime.
Volunteer Computing is a form of distributed computing in which the general public offers processing power and storage to scientific research projects. A large variety of Volunteer Computing systems (VCS) have been pr...
详细信息
Volunteer Computing is a form of distributed computing in which the general public offers processing power and storage to scientific research projects. A large variety of Volunteer Computing systems (VCS) have been proposed in the literature which use different architectures from client/server to P2P. This paper aims to provide a formal abstraction of VCS. At first, we identify three key roles played by VCS computing resources. Then, a formal model and related methods concerning Volunteer Computing are introduced. Relationships among elements are also characterized, based on set theory and operational reduction rules. We apply this model to describe a part of the XtremWeb protocol. Our results can help to lay a substantial foundation for the research on formalisms of Volunteer Computing.
Computer-based knowledge management systems have become a major part of today's communication system, and with the Internet as a medium, distance is no longer the barrier. In line with this development, we propose...
详细信息
Computer-based knowledge management systems have become a major part of today's communication system, and with the Internet as a medium, distance is no longer the barrier. In line with this development, we propose an interactive online multi-user document editing system for the use of collaborative report paper creation. The goal of this study is not only in developing the system, but also to create an environment where collaborative report paper creation is possible even if users are not in the same *** paper presents a collaborative report paper creation tool for the use of creating report papers within an industrial *** particular, we explain how the system works, how the interface lookslike, as well as the advantages of our system incomparison to other existing systems.
As modern supercomputing systems reach the peta-flop performance range, they grow in both size and complexity. This makes them increasingly vulnerable to failures from a variety of causes. Checkpointing is a popular t...
详细信息
ISBN:
(纸本)9781424437511
As modern supercomputing systems reach the peta-flop performance range, they grow in both size and complexity. This makes them increasingly vulnerable to failures from a variety of causes. Checkpointing is a popular technique for tolerating such failures, enabling applications to periodically save their state and restart computation after a failure. Although a many automated system-level checkpointing solutions are currently available to HPC users, manual application-level checkpointing remains more popular due to its superior performance. This paper improves performance of automated checkpointing via a compiler analysis for incremental checkpointing. This analysis, which works with both sequential and OpenMP applications, reduces checkpoint sizes by as much as 80% and enables asynchronous checkpointing.
Clock is an important notion in TA (Timed automata). In order to manipulate clock easily and conveniently in TA, a mechanized system called FVofTA (formal verification of timed automata) for specifying and reasoning a...
详细信息
Clock is an important notion in TA (Timed automata). In order to manipulate clock easily and conveniently in TA, a mechanized system called FVofTA (formal verification of timed automata) for specifying and reasoning about real-time systems using TA theory in PVS (prototype verification system) is presented in this paper. This system includes two parts: one for modeling real-time system using TA template in PVS and the other for proof intending for formal verification of real-time system. As one of the important modular of FVofTA, clock manipulations are given in PVS specification and mainly include (1) clock interpretation and clock constraints, (2) clock region equivalence definition and its application, and (3) the clock zone and its DBM (difference-bound matrices) representation. Finally, a case study is investigated with the aid of clock manipulation theories and the results are satisfied.
Over the last decade, commodity graphics processors (GPUs) have evolved from fixed-function graphics units into powerful, programmable data-parallel processors. Today's GPU is capable of sustaining computation rat...
详细信息
Over the last decade, commodity graphics processors (GPUs) have evolved from fixed-function graphics units into powerful, programmable data-parallel processors. Today's GPU is capable of sustaining computation rates substantially greater than today's modern CPUs, with technology trends indicating a widening gap in the future. Researchers in the rapidly evolving field of GPU computing have demonstrated mappings to these processors for a wide range of computationally intensive tasks, and new programming environments offer the promise of a wider role for GPU computing in the coming years. In this talk I will begin by discussing the motivation and background for GPU computing and describe some of the recent advances in the field. The field of GPU computing has substantially changed over its short lifetime due to new applications, techniques, programming models, and hardware. As parallel computing has decidedly moved into the mainstream, the lessons of GPU computing are applicable to both today's systems as well as to the designers of tomorrow's systems. I will address the way a GPU-CPU system is a heterogeneous system and why it is an interesting one, and discuss some case studies on how one can program and use such a system.
High-performance cluster networks achieve very high throughput thanks to zero-copy techniques that require pinning of application buffers in physical memory. The Open-MX stack implements message passing over generic E...
详细信息
High-performance cluster networks achieve very high throughput thanks to zero-copy techniques that require pinning of application buffers in physical memory. The Open-MX stack implements message passing over generic Ethernet hardware with similar needs. We present the design of an innovative pinning model in Open-MX based on the decoupling of memory pinning from the application. This idea eases the implementation of a reliable pinning cache in the kernel and enables full overlap of pinning with communication. The pinning cache enables performance improvement when the application reuses the same buffers multiple times, while overlapped pinning is also applicable to other applications. Performance evaluation shows that both these optimizations bring from 5 up to 20% throughput improvements depending on the host and network performance.
暂无评论