65,915 research outputs found
Algebraic Watchdog: Mitigating Misbehavior in Wireless Network Coding
We propose a secure scheme for wireless network coding, called the algebraic
watchdog. By enabling nodes to detect malicious behaviors probabilistically and
use overheard messages to police their downstream neighbors locally, the
algebraic watchdog delivers a secure global self-checking network. Unlike
traditional Byzantine detection protocols which are receiver-based, this
protocol gives the senders an active role in checking the node downstream. The
key idea is inspired by Marti et al.'s watchdog-pathrater, which attempts to
detect and mitigate the effects of routing misbehavior.
As an initial building block of a such system, we first focus on a two-hop
network. We present a graphical model to understand the inference process nodes
execute to police their downstream neighbors; as well as to compute, analyze,
and approximate the probabilities of misdetection and false detection. In
addition, we present an algebraic analysis of the performance using an
hypothesis testing framework that provides exact formulae for probabilities of
false detection and misdetection.
We then extend the algebraic watchdog to a more general network setting, and
propose a protocol in which we can establish trust in coded systems in a
distributed manner. We develop a graphical model to detect the presence of an
adversarial node downstream within a general multi-hop network. The structure
of the graphical model (a trellis) lends itself to well-known algorithms, such
as the Viterbi algorithm, which can compute the probabilities of misdetection
and false detection. We show analytically that as long as the min-cut is not
dominated by the Byzantine adversaries, upstream nodes can monitor downstream
neighbors and allow reliable communication with certain probability. Finally,
we present simulation results that support our analysis.Comment: 10 pages, 10 figures, Submitted to IEEE Journal on Selected Areas in
Communications (JSAC) "Advances in Military Networking and Communications
Algebraic model checking for discrete linear dynamical systems
Model checking infinite-state systems is one of the central challenges in automated verification. In this survey we focus on an important and fundamental subclass of infinite-state systems, namely discrete linear dynamical systems. While such systems are ubiquitous in mathematics, physics, engineering, etc., in the present context our motivation stems from their relevance to the formal analysis and verification of program loops, weighted automata, hybrid systems, and control systems, amongst many others. Our main object of study is the problem of model checking temporal properties on the infinite orbit of a linear dynamical system, and our principal contribution is to show that for a rich class of properties this problem can be reduced to certain classical decision problems on linear recurrence sequences, notably the Skolem Problem. This leads us to discuss recent advances on the latter and to highlight the prospects for further progress on charting the algorithmic landscape of linear recurrence sequences and linear dynamical systems
Algebraic Model Checking for Discrete Linear Dynamical Systems
Model checking infinite-state systems is one of the central challenges in automated verification. In this survey we focus on an important and fundamental subclass of infinite-state systems, namely discrete linear dynamical systems. While such systems are ubiquitous in mathematics, physics, engineering, etc., in the present context our motivation stems from their relevance to the formal analysis and verification of program loops, weighted automata, hybrid systems, and control systems, amongst many others. Our main object of study is the problem of model checking temporal properties on the infinite orbit of a linear dynamical system, and our principal contribution is to show that for a rich class of properties this problem can be reduced to certain classical decision problems on linear recurrence sequences, notably the Skolem Problem. This leads us to discuss recent advances on the latter and to highlight the prospects for further progress on charting the algorithmic landscape of linear recurrence sequences and linear dynamical systems
ΠΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΎΠ½Π½ΡΠ΅ ΠΏΡΠΎΡΠ΅Π΄ΡΡΡ Π² Π°ΡΡΠΈΠ½Π½ΠΎΠΉ ΠΏΡΠΎΠ²Π΅ΡΠΊΠ΅ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ
Symbolic model checking is based on a compact representation of sets of states and transition relations. At present there are three basic approaches of symbolic model checking: BDD-methods, bounded model checking using SAT-solvers, and various algebraic techniques, for example, constraint based model checking and regular model checking. In this paper we suggest improved algorithms for an algebraic data representation, namely, optimization algorithms for affine data structures.Π‘ΠΈΠΌΠ²ΠΎΠ»ΡΠ½Π°Ρ ΠΏΡΠΎΠ²Π΅ΡΠΊΠ° Π½Π° ΠΌΠΎΠ΄Π΅Π»ΠΈ ΠΎΡΠ½ΠΎΠ²Π°Π½Π° Π½Π° ΠΊΠΎΠΌΠΏΠ°ΠΊΡΠ½ΠΎΠΌ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΠΈ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ². ΠΠ° Π΄Π°Π½Π½ΡΠΉ ΠΌΠΎΠΌΠ΅Π½Ρ Π΅ΡΡΡ ΡΡΠΈ ΠΎΡΠ½ΠΎΠ²Π½ΡΡ
Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΡΠΈΠΌΠ²ΠΎΠ»ΡΠ½ΠΎΠΉ ΠΏΡΠΎΠ²Π΅ΡΠΊΠΈ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ: ΠΌΠ΅ΡΠΎΠ΄Ρ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΠ΅ Π½Π° Π±ΠΈΠ½Π°ΡΠ½ΡΡ
ΡΠ°Π·ΡΠ΅ΡΠ°ΡΡΠΈΡ
Π΄ΠΈΠ°Π³ΡΠ°ΠΌΠΌΠ°Ρ
, ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½Π½Π°Ρ ΠΏΡΠΎΠ²Π΅ΡΠΊΠ° ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΠ°Ρ SAT-ΡΠ΅ΡΠ°ΡΠ΅Π»ΠΈ, ΠΈ ΡΠ°Π·Π»ΠΈΡΠ½ΡΠ΅ Π°Π»Π³Π΅Π±ΡΠ°ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Ρ ΠΊ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΠΌΡ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΡ Π΄Π°Π½Π½ΡΡ
. Π Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΡΡΡ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅ΡΡ ΡΠ»ΡΡΡΠ΅Π½Π½ΡΠ΅ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ ΠΌΠ°Π½ΠΈΠΏΡΠ»ΡΡΠΈΠΈ Ρ Π°Π»Π³Π΅Π±ΡΠ°ΠΈΡΠ΅ΡΠΊΠΈΠΌ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΠ΅ΠΌ Π΄Π°Π½Π½ΡΡ
, Π° ΠΈΠΌΠ΅Π½Π½ΠΎ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ Π°ΡΡΠΈΠ½Π½ΡΡ
ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΠΉ Π΄Π°Π½Π½ΡΡ
A balancing act : analyzing a distributed lift system
The process-algebraic language Β΅crl is used to analyze an existing distributed system for lifting trucks. Four errors were found in the original design. We propose solutions for these problems and show by means of model-checking that the modified system meets the requirements
- β¦