12,512 research outputs found
AliEn Resource Brokers
AliEn (ALICE Environment) is a lightweight GRID framework developed by the
Alice Collaboration. When the experiment starts running, it will collect data
at a rate of approximately 2 PB per year, producing O(109) files per year. All
these files, including all simulated events generated during the preparation
phase of the experiment, must be accounted and reliably tracked in the GRID
environment. The backbone of AliEn is a distributed file catalogue, which
associates universal logical file name to physical file names for each dataset
and provides transparent access to datasets independently of physical location.
The file replication and transport is carried out under the control of the File
Transport Broker. In addition, the file catalogue maintains information about
every job running in the system. The jobs are distributed by the Job Resource
Broker that is implemented using a simplified pull (as opposed to traditional
push) architecture. This paper describes the Job and File Transport Resource
Brokers and shows that a similar architecture can be applied to solve both
problems.Comment: 5 pages, 8 figures, CHEP 03 conferenc
Reuse It Or Lose It: More Efficient Secure Computation Through Reuse of Encrypted Values
Two-party secure function evaluation (SFE) has become significantly more
feasible, even on resource-constrained devices, because of advances in
server-aided computation systems. However, there are still bottlenecks,
particularly in the input validation stage of a computation. Moreover, SFE
research has not yet devoted sufficient attention to the important problem of
retaining state after a computation has been performed so that expensive
processing does not have to be repeated if a similar computation is done again.
This paper presents PartialGC, an SFE system that allows the reuse of encrypted
values generated during a garbled-circuit computation. We show that using
PartialGC can reduce computation time by as much as 96% and bandwidth by as
much as 98% in comparison with previous outsourcing schemes for secure
computation. We demonstrate the feasibility of our approach with two sets of
experiments, one in which the garbled circuit is evaluated on a mobile device
and one in which it is evaluated on a server. We also use PartialGC to build a
privacy-preserving "friend finder" application for Android. The reuse of
previous inputs to allow stateful evaluation represents a new way of looking at
SFE and further reduces computational barriers.Comment: 20 pages, shorter conference version published in Proceedings of the
2014 ACM SIGSAC Conference on Computer and Communications Security, Pages
582-596, ACM New York, NY, US
Transforming ASN.1 Specifications into CafeOBJ to assist with Property Checking
The adoption of algebraic specification/formal method techniques by the
networks' research community is happening slowly but steadily. We work towards
a software environment that can translate a protocol's specification, from
Abstract Syntax Notation One (ASN.1 - a very popular specification language
with many applications), into the powerful algebraic specification language
CafeOBJ. The resulting code can be used to check, validate and falsify critical
properties of systems, at the pre-coding stage of development. In this paper,
we introduce some key elements of ASN.1 and CafeOBJ and sketch some first steps
towards the implementation of such a tool including a case study.Comment: 8 pages, 12 figure
Formal Verification of Probabilistic SystemC Models with Statistical Model Checking
Transaction-level modeling with SystemC has been very successful in
describing the behavior of embedded systems by providing high-level executable
models, in which many of them have inherent probabilistic behaviors, e.g.,
random data and unreliable components. It thus is crucial to have both
quantitative and qualitative analysis of the probabilities of system
properties. Such analysis can be conducted by constructing a formal model of
the system under verification and using Probabilistic Model Checking (PMC).
However, this method is infeasible for large systems, due to the state space
explosion. In this article, we demonstrate the successful use of Statistical
Model Checking (SMC) to carry out such analysis directly from large SystemC
models and allow designers to express a wide range of useful properties. The
first contribution of this work is a framework to verify properties expressed
in Bounded Linear Temporal Logic (BLTL) for SystemC models with both timed and
probabilistic characteristics. Second, the framework allows users to expose a
rich set of user-code primitives as atomic propositions in BLTL. Moreover,
users can define their own fine-grained time resolution rather than the
boundary of clock cycles in the SystemC simulation. The third contribution is
an implementation of a statistical model checker. It contains an automatic
monitor generation for producing execution traces of the
model-under-verification (MUV), the mechanism for automatically instrumenting
the MUV, and the interaction with statistical model checking algorithms.Comment: Journal of Software: Evolution and Process. Wiley, 2017. arXiv admin
note: substantial text overlap with arXiv:1507.0818
Symbolic Reachability Analysis of B through ProB and LTSmin
We present a symbolic reachability analysis approach for B that can provide a
significant speedup over traditional explicit state model checking. The
symbolic analysis is implemented by linking ProB to LTSmin, a high-performance
language independent model checker. The link is achieved via LTSmin's PINS
interface, allowing ProB to benefit from LTSmin's analysis algorithms, while
only writing a few hundred lines of glue-code, along with a bridge between ProB
and C using ZeroMQ. ProB supports model checking of several formal
specification languages such as B, Event-B, Z and TLA. Our experiments are
based on a wide variety of B-Method and Event-B models to demonstrate the
efficiency of the new link. Among the tested categories are state space
generation and deadlock detection; but action detection and invariant checking
are also feasible in principle. In many cases we observe speedups of several
orders of magnitude. We also compare the results with other approaches for
improving model checking, such as partial order reduction or symmetry
reduction. We thus provide a new scalable, symbolic analysis algorithm for the
B-Method and Event-B, along with a platform to integrate other model checking
improvements via LTSmin in the future
The AliEn system, status and perspectives
AliEn is a production environment that implements several components of the
Grid paradigm needed to simulate, reconstruct and analyse HEP data in a
distributed way. The system is built around Open Source components, uses the
Web Services model and standard network protocols to implement the computing
platform that is currently being used to produce and analyse Monte Carlo data
at over 30 sites on four continents. The aim of this paper is to present the
current AliEn architecture and outline its future developments in the light of
emerging standards.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, Word, 10 figures. PSN
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