101,124 research outputs found
The STRESS Method for Boundary-point Performance Analysis of End-to-end Multicast Timer-Suppression Mechanisms
Evaluation of Internet protocols usually uses random scenarios or scenarios
based on designers' intuition. Such approach may be useful for average-case
analysis but does not cover boundary-point (worst or best-case) scenarios. To
synthesize boundary-point scenarios a more systematic approach is needed.In
this paper, we present a method for automatic synthesis of worst and best case
scenarios for protocol boundary-point evaluation.
Our method uses a fault-oriented test generation (FOTG) algorithm for
searching the protocol and system state space to synthesize these scenarios.
The algorithm is based on a global finite state machine (FSM) model. We extend
the algorithm with timing semantics to handle end-to-end delays and address
performance criteria. We introduce the notion of a virtual LAN to represent
delays of the underlying multicast distribution tree. The algorithms used in
our method utilize implicit backward search using branch and bound techniques
and start from given target events. This aims to reduce the search complexity
drastically. As a case study, we use our method to evaluate variants of the
timer suppression mechanism, used in various multicast protocols, with respect
to two performance criteria: overhead of response messages and response time.
Simulation results for reliable multicast protocols show that our method
provides a scalable way for synthesizing worst-case scenarios automatically.
Results obtained using stress scenarios differ dramatically from those obtained
through average-case analyses. We hope for our method to serve as a model for
applying systematic scenario generation to other multicast protocols.Comment: 24 pages, 10 figures, IEEE/ACM Transactions on Networking (ToN) [To
appear
I2PA : An Efficient ABC for IoT
Internet of Things (IoT) is very attractive because of its promises. However,
it brings many challenges, mainly issues about privacy preserving and
lightweight cryptography. Many schemes have been designed so far but none of
them simultaneously takes into account these aspects. In this paper, we propose
an efficient ABC scheme for IoT devices. We use ECC without pairing, blind
signing and zero knowledge proof. Our scheme supports block signing, selective
disclosure and randomization. It provides data minimization and transactions'
unlinkability. Our construction is efficient since smaller key size can be used
and computing time can be reduced. As a result, it is a suitable solution for
IoT devices characterized by three major constraints namely low energy power,
small storage capacity and low computing power
The Dafny Integrated Development Environment
In recent years, program verifiers and interactive theorem provers have
become more powerful and more suitable for verifying large programs or proofs.
This has demonstrated the need for improving the user experience of these tools
to increase productivity and to make them more accessible to non-experts. This
paper presents an integrated development environment for Dafny-a programming
language, verifier, and proof assistant-that addresses issues present in most
state-of-the-art verifiers: low responsiveness and lack of support for
understanding non-obvious verification failures. The paper demonstrates several
new features that move the state-of-the-art closer towards a verification
environment that can provide verification feedback as the user types and can
present more helpful information about the program or failed verifications in a
demand-driven and unobtrusive way.Comment: In Proceedings F-IDE 2014, arXiv:1404.578
Person Re-Identification by Deep Joint Learning of Multi-Loss Classification
Existing person re-identification (re-id) methods rely mostly on either
localised or global feature representation alone. This ignores their joint
benefit and mutual complementary effects. In this work, we show the advantages
of jointly learning local and global features in a Convolutional Neural Network
(CNN) by aiming to discover correlated local and global features in different
context. Specifically, we formulate a method for joint learning of local and
global feature selection losses designed to optimise person re-id when using
only generic matching metrics such as the L2 distance. We design a novel CNN
architecture for Jointly Learning Multi-Loss (JLML) of local and global
discriminative feature optimisation subject concurrently to the same re-id
labelled information. Extensive comparative evaluations demonstrate the
advantages of this new JLML model for person re-id over a wide range of
state-of-the-art re-id methods on five benchmarks (VIPeR, GRID, CUHK01, CUHK03,
Market-1501).Comment: Accepted by IJCAI 201
Security by Spatial Reference:Using Relative Positioning to Authenticate Devices for Spontaneous Interaction
Spontaneous interaction is a desirable characteristic associated with mobile and ubiquitous computing. The aim is to enable users to connect their personal devices with devices encountered in their environment in order to take advantage of interaction opportunities in accordance with their situation. However, it is difficult to secure spontaneous interaction as this requires authentication of the encountered device, in the absence of any prior knowledge of the device. In this paper we present a method for establishing and securing spontaneous interactions on the basis of emphspatial references that capture the spatial relationship of the involved devices. Spatial references are obtained by accurate sensing of relative device positions, presented to the user for initiation of interactions, and used in a peer authentication protocol that exploits a novel mechanism for message transfer over ultrasound to ensures spatial authenticity of the sender
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