4,643 research outputs found
Parc#: parallel computing with c# in .net
This paper describes experiments with the development of a parallel computing platform on top of a compatible C# implementation: the Mono project. This implementation has the advantage of running on both Windows and UNIX platforms and has reached a stable state. This paper presents performance results obtained and compares these results with implementations in Java/RMI. The results show that the Mono network performance, critical for parallel applications, has greatly improved in recent releases, that it is superior to the Java RMI and is close to the performance of the new Java nio package. The Mono virtual machine is not yet so highly tuned as the Sun JVM and Thread scheduling needs to be improved. Overall, this platform is a new alternative to explore in the future for parallel computing(undefined
To NACK or not to NACK? Negative Acknowledgments in Information-Centric Networking
Information-Centric Networking (ICN) is an internetworking paradigm that
offers an alternative to the current IP\nobreakdash-based Internet
architecture. ICN's most distinguishing feature is its emphasis on information
(content) instead of communication endpoints. One important open issue in ICN
is whether negative acknowledgments (NACKs) at the network layer are useful for
notifying downstream nodes about forwarding failures, or requests for incorrect
or non-existent information. In benign settings, NACKs are beneficial for ICN
architectures, such as CCNx and NDN, since they flush state in routers and
notify consumers. In terms of security, NACKs seem useful as they can help
mitigating so-called Interest Flooding attacks. However, as we show in this
paper, network-layer NACKs also have some unpleasant security implications. We
consider several types of NACKs and discuss their security design requirements
and implications. We also demonstrate that providing secure NACKs triggers the
threat of producer-bound flooding attacks. Although we discuss some potential
countermeasures to these attacks, the main conclusion of this paper is that
network-layer NACKs are best avoided, at least for security reasons.Comment: 10 pages, 7 figure
Drift without flux: Brownian walker with a space dependent diffusion coefficient
Space dependent diffusion of micrometer sized particles has been directly
observed using digital video microscopy. The particles were trapped between two
nearly parallel walls making their confinement position dependent.
Consequently, not only did we measure a diffusion coefficient which depended on
the particles' position, but also report and explain a new effect: a drift of
the particles' individual positions in the direction of the diffusion
coefficient gradient, in the absence of any external force or concentration
gradient.Comment: 4 pages, 4 ps figures, include
Fast-ParC: Position Aware Global Kernel for ConvNets and ViTs
Transformer models have made tremendous progress in various fields in recent
years. In the field of computer vision, vision transformers (ViTs) also become
strong alternatives to convolutional neural networks (ConvNets), yet they have
not been able to replace ConvNets since both have their own merits. For
instance, ViTs are good at extracting global features with attention mechanisms
while ConvNets are more efficient in modeling local relationships due to their
strong inductive bias. A natural idea that arises is to combine the strengths
of both ConvNets and ViTs to design new structures. In this paper, we propose a
new basic neural network operator named position-aware circular convolution
(ParC) and its accelerated version Fast-ParC. The ParC operator can capture
global features by using a global kernel and circular convolution while keeping
location sensitiveness by employing position embeddings. Our Fast-ParC further
reduces the O(n2) time complexity of ParC to O(n log n) using Fast Fourier
Transform. This acceleration makes it possible to use global convolution in the
early stages of models with large feature maps, yet still maintains the overall
computational cost comparable with using 3x3 or 7x7 kernels. The proposed
operation can be used in a plug-and-play manner to 1) convert ViTs to
pure-ConvNet architecture to enjoy wider hardware support and achieve higher
inference speed; 2) replacing traditional convolutions in the deep stage of
ConvNets to improve accuracy by enlarging the effective receptive field.
Experiment results show that our ParC op can effectively enlarge the receptive
field of traditional ConvNets, and adopting the proposed op benefits both ViTs
and ConvNet models on all three popular vision tasks, image classification,
objectComment: 19 pages, 8 figures, 11 tables. A preliminary version of this paper
has been published in ECCV 2022 and it can be find in arXiv:2203.0395
The Use of Audio in Minimal Access Surgery
In minimal access surgery (MAS) (also known as minimally invasive surgery), operations are carried out by making small incisions in the skin and inserting special apparatus into potential body cavities through those incisions. Laparoscopic MAS procedures are conducted in the patient’s abdomen. The aim of MAS is faster recovery, shorter hospitalisation and fewer major post-operative complications; all resulting in lower societal cost with better patient acceptability. The technique is markedly dependent on supporting technologies for vision, instrumentation, energy delivery, anaesthesia, and monitoring. However, in practice, much MAS continues to
take longer and be associated with an undesirable frequency of unwanted minor (or occasionally major) mishaps. Many of these difficulties result precisely from the complexity and mal-adaptation of the additional technology and from lack of
familiarity with it. A survey of South East England surgeons showed the two main stress factors on surgeons to be the technical difficulty of the procedure and time pressures placed on the surgeon by third parties.
Many of the problems associated with MAS operations are linked to the control and monitoring of the equipment. This paper describes work begun to explore ergonomic enhancements to laparoscopic operating technology that could result in faster and safer laparoscopic operations, less surgeon stress and reduce dependence on ancillary staff.
Auditory displays have been used to communicate complex information to users in a modality that is complementary to the visual channel. This paper proposes the development of a control and feedback system that will make use of auditory displays to improve the amount of information that can be communicated to the surgeon and his assistant without overloading the visual channel. Control of the system would be enhanced by the addition of voice input to allow the surgeon direct control
A First Step Towards Automatically Building Network Representations
To fully harness Grids, users or middlewares must have some knowledge on the
topology of the platform interconnection network. As such knowledge is usually
not available, one must uses tools which automatically build a topological
network model through some measurements. In this article, we define a
methodology to assess the quality of these network model building tools, and we
apply this methodology to representatives of the main classes of model builders
and to two new algorithms. We show that none of the main existing techniques
build models that enable to accurately predict the running time of simple
application kernels for actual platforms. However some of the new algorithms we
propose give excellent results in a wide range of situations
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