17,744 research outputs found
Partially ordered distributed computations on asynchronous point-to-point networks
Asynchronous executions of a distributed algorithm differ from each other due
to the nondeterminism in the order in which the messages exchanged are handled.
In many situations of interest, the asynchronous executions induced by
restricting nondeterminism are more efficient, in an application-specific
sense, than the others. In this work, we define partially ordered executions of
a distributed algorithm as the executions satisfying some restricted orders of
their actions in two different frameworks, those of the so-called event- and
pulse-driven computations. The aim of these restrictions is to characterize
asynchronous executions that are likely to be more efficient for some important
classes of applications. Also, an asynchronous algorithm that ensures the
occurrence of partially ordered executions is given for each case. Two of the
applications that we believe may benefit from the restricted nondeterminism are
backtrack search, in the event-driven case, and iterative algorithms for
systems of linear equations, in the pulse-driven case
Execution replay and debugging
As most parallel and distributed programs are internally non-deterministic --
consecutive runs with the same input might result in a different program flow
-- vanilla cyclic debugging techniques as such are useless. In order to use
cyclic debugging tools, we need a tool that records information about an
execution so that it can be replayed for debugging. Because recording
information interferes with the execution, we must limit the amount of
information and keep the processing of the information fast. This paper
contains a survey of existing execution replay techniques and tools.Comment: In M. Ducasse (ed), proceedings of the Fourth International Workshop
on Automated Debugging (AADebug 2000), August 2000, Munich. cs.SE/001003
Communication Theoretic Data Analytics
Widespread use of the Internet and social networks invokes the generation of
big data, which is proving to be useful in a number of applications. To deal
with explosively growing amounts of data, data analytics has emerged as a
critical technology related to computing, signal processing, and information
networking. In this paper, a formalism is considered in which data is modeled
as a generalized social network and communication theory and information theory
are thereby extended to data analytics. First, the creation of an equalizer to
optimize information transfer between two data variables is considered, and
financial data is used to demonstrate the advantages. Then, an information
coupling approach based on information geometry is applied for dimensionality
reduction, with a pattern recognition example to illustrate the effectiveness.
These initial trials suggest the potential of communication theoretic data
analytics for a wide range of applications.Comment: Published in IEEE Journal on Selected Areas in Communications, Jan.
201
Causal Boxes: Quantum Information-Processing Systems Closed under Composition
Complex information-processing systems, for example quantum circuits,
cryptographic protocols, or multi-player games, are naturally described as
networks composed of more basic information-processing systems. A modular
analysis of such systems requires a mathematical model of systems that is
closed under composition, i.e., a network of these objects is again an object
of the same type. We propose such a model and call the corresponding systems
causal boxes.
Causal boxes capture superpositions of causal structures, e.g., messages sent
by a causal box A can be in a superposition of different orders or in a
superposition of being sent to box B and box C. Furthermore, causal boxes can
model systems whose behavior depends on time. By instantiating the Abstract
Cryptography framework with causal boxes, we obtain the first composable
security framework that can handle arbitrary quantum protocols and relativistic
protocols.Comment: 44+24 pages, 16 figures. v3: minor edits based on referee comments,
matches published version up to layout. v2: definition of causality weakened,
new reference
The ISIS project: Fault-tolerance in large distributed systems
The semi-annual status report covers activities of the ISIS project during the second half of 1989. The project had several independent objectives: (1) At the level of the ISIS Toolkit, ISIS release V2.0 was completed, containing bypass communication protocols. Performance of the system is greatly enhanced by this change, but the initial software release is limited in some respects. (2) The Meta project focused on the definition of the Lomita programming language for specifying rules that monitor sensors for conditions of interest and triggering appropriate reactions. This design was completed, and implementation of Lomita is underway on the Meta 2.0 platform. (3) The Deceit file system effort completed a prototype. It is planned to make Deceit available for use in two hospital information systems. (4) A long-haul communication subsystem project was completed and can be used as part of ISIS. This effort resulted in tools for linking ISIS systems on different LANs together over long-haul communications lines. (5) Magic Lantern, a graphical tool for building application monitoring and control interfaces, is included as part of the general ISIS releases
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