2,821 research outputs found
Towards a Swiss National Research Infrastructure
In this position paper we describe the current status and plans for a Swiss
National Research Infrastructure. Swiss academic and research institutions are
very autonomous. While being loosely coupled, they do not rely on any
centralized management entities. Therefore, a coordinated national research
infrastructure can only be established by federating the various resources
available locally at the individual institutions. The Swiss Multi-Science
Computing Grid and the Swiss Academic Compute Cloud projects serve already a
large number of diverse user communities. These projects also allow us to test
the operational setup of such a heterogeneous federated infrastructure
Multi-physics Extension of OpenFMO Framework
OpenFMO framework, an open-source software (OSS) platform for Fragment
Molecular Orbital (FMO) method, is extended to multi-physics simulations (MPS).
After reviewing the several FMO implementations on distributed computer
environments, the subsequent development planning corresponding to MPS is
presented. It is discussed which should be selected as a scientific software,
lightweight and reconfigurable form or large and self-contained form.Comment: 4 pages with 11 figure files, to appear in the Proceedings of ICCMSE
200
Deep Learning for Real-time Gravitational Wave Detection and Parameter Estimation: Results with Advanced LIGO Data
The recent Nobel-prize-winning detections of gravitational waves from merging
black holes and the subsequent detection of the collision of two neutron stars
in coincidence with electromagnetic observations have inaugurated a new era of
multimessenger astrophysics. To enhance the scope of this emergent field of
science, we pioneered the use of deep learning with convolutional neural
networks, that take time-series inputs, for rapid detection and
characterization of gravitational wave signals. This approach, Deep Filtering,
was initially demonstrated using simulated LIGO noise. In this article, we
present the extension of Deep Filtering using real data from LIGO, for both
detection and parameter estimation of gravitational waves from binary black
hole mergers using continuous data streams from multiple LIGO detectors. We
demonstrate for the first time that machine learning can detect and estimate
the true parameters of real events observed by LIGO. Our results show that Deep
Filtering achieves similar sensitivities and lower errors compared to
matched-filtering while being far more computationally efficient and more
resilient to glitches, allowing real-time processing of weak time-series
signals in non-stationary non-Gaussian noise with minimal resources, and also
enables the detection of new classes of gravitational wave sources that may go
unnoticed with existing detection algorithms. This unified framework for data
analysis is ideally suited to enable coincident detection campaigns of
gravitational waves and their multimessenger counterparts in real-time.Comment: 6 pages, 7 figures; First application of deep learning to real LIGO
events; Includes direct comparison against matched-filterin
Generalized Asynchronous Systems
The paper is devoted to a mathematical model of concurrency the special case
of which is asynchronous system. Distributed asynchronous automata are
introduced here. It is proved that the Petri nets and transition systems with
independence can be considered like the distributed asynchronous automata. Time
distributed asynchronous automata are defined in standard way by the map which
assigns time intervals to events. It is proved that the time distributed
asynchronous automata are generalized the time Petri nets and asynchronous
systems.Comment: 8 page
Towards a complexity theory for the congested clique
The congested clique model of distributed computing has been receiving
attention as a model for densely connected distributed systems. While there has
been significant progress on the side of upper bounds, we have very little in
terms of lower bounds for the congested clique; indeed, it is now know that
proving explicit congested clique lower bounds is as difficult as proving
circuit lower bounds.
In this work, we use various more traditional complexity-theoretic tools to
build a clearer picture of the complexity landscape of the congested clique:
-- Nondeterminism and beyond: We introduce the nondeterministic congested
clique model (analogous to NP) and show that there is a natural canonical
problem family that captures all problems solvable in constant time with
nondeterministic algorithms. We further generalise these notions by introducing
the constant-round decision hierarchy (analogous to the polynomial hierarchy).
-- Non-constructive lower bounds: We lift the prior non-uniform counting
arguments to a general technique for proving non-constructive uniform lower
bounds for the congested clique. In particular, we prove a time hierarchy
theorem for the congested clique, showing that there are decision problems of
essentially all complexities, both in the deterministic and nondeterministic
settings.
-- Fine-grained complexity: We map out relationships between various natural
problems in the congested clique model, arguing that a reduction-based
complexity theory currently gives us a fairly good picture of the complexity
landscape of the congested clique
Brief Announcement: Asymmetric Distributed Trust
Quorum systems are a key abstraction in distributed fault-tolerant computing for capturing trust assumptions. They can be found at the core of many algorithms for implementing reliable broadcasts, shared memory, consensus and other problems. This paper introduces asymmetric Byzantine quorum systems that model subjective trust. Every process is free to choose which combinations of other processes it trusts and which ones it considers faulty. Asymmetric quorum systems strictly generalize standard Byzantine quorum systems, which have only one global trust assumption for all processes. This work also presents protocols that implement abstractions of shared memory and broadcast primitives with processes prone to Byzantine faults and asymmetric trust. The model and protocols pave the way for realizing more elaborate algorithms with asymmetric trust
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