120 research outputs found
Network anomaly detection: a survey and comparative analysis of stochastic and deterministic methods
7 pages. 1 more figure than final CDC 2013 versionWe present five methods to the problem of network anomaly detection. These methods cover most of the common techniques in the anomaly detection field, including Statistical Hypothesis Tests (SHT), Support Vector Machines (SVM) and clustering analysis. We evaluate all methods in a simulated network that consists of nominal data, three flow-level anomalies and one packet-level attack. Through analyzing the results, we point out the advantages and disadvantages of each method and conclude that combining the results of the individual methods can yield improved anomaly detection results
MORPH: A Reference Architecture for Configuration and Behaviour Self-Adaptation
An architectural approach to self-adaptive systems involves runtime change of
system configuration (i.e., the system's components, their bindings and
operational parameters) and behaviour update (i.e., component orchestration).
Thus, dynamic reconfiguration and discrete event control theory are at the
heart of architectural adaptation. Although controlling configuration and
behaviour at runtime has been discussed and applied to architectural
adaptation, architectures for self-adaptive systems often compound these two
aspects reducing the potential for adaptability. In this paper we propose a
reference architecture that allows for coordinated yet transparent and
independent adaptation of system configuration and behaviour
Optimal Minimax Mobile Sensor Scheduling Over a Network
We investigate the problem of monitoring multiple targets using a single
mobile sensor, with the goal of minimizing the maximum estimation error among
all the targets over long time horizons. The sensor can move in a
network-constrained structure, where it has to plan which targets to visit and
for how long to dwell at each node. We prove that in an optimal observation
time allocation, the peak uncertainty is the same among all the targets. By
further restricting the agent policy to only visit each target once every
cycle, we develop a scheme to optimize the agent's behavior that is
significantly simpler computationally when compared to previous approaches for
similar problems
Effective RFID-based object tracking for manufacturing
International audienceAbstract Automated Identification and in particular, Radio Frequency Identification (RFID) promises to assist with the automation of mass customised production processes by simplifying the retrieval, tracking and usage of highly specialised components. RFID has long been used to gather a history or trace of object movements, but its use as an integral part of the automated control process is yet to be fully exploited. Such (automated) use places stringent demands on the quality of the sensor data collected and the method used to interpret that data. In particular, this paper focuses on the issue of correctly identifying, tracking and dealing with aggregated objects in customised production with the use of RFID. In particular, this work presents approaches for making best use of RFID data in this context. The presented approach is evaluated in the context of a laboratory manufacturing system that produces customised gift boxes
A Process Algebra for Supervisory Coordination
A supervisory controller controls and coordinates the behavior of different
components of a complex machine by observing their discrete behaviour.
Supervisory control theory studies automated synthesis of controller models,
known as supervisors, based on formal models of the machine components and a
formalization of the requirements. Subsequently, code generation can be used to
implement this supervisor in software, on a PLC, or embedded microprocessor. In
this article, we take a closer look at the control loop that couples the
supervisory controller and the machine. We model both event-based and
state-based observations using process algebra and bisimulation-based
semantics. The main application area of supervisory control that we consider is
coordination, referred to as supervisory coordination, and we give an academic
and an industrial example, discussing the process-theoretic concepts employed.Comment: In Proceedings PACO 2011, arXiv:1108.145
Probabilistic Programming
Probabilistic programs are usual functional or imperative programs with two added constructs: (1) the ability to draw values at random from distributions, and (2) the ability to condition values of variables in a program via observations. Models from diverse application areas such as computer vision, coding theory, cryptographic protocols, biology and reliability analysis can be written as probabilistic programs. Probabilistic inference is the problem of computing an explicit representation of the probability distribution implicitly specified by a probabilistic program. Depending on the application, the desired output from inference may vary-we may want to estimate the expected value of some function f with respect to the distribution, or the mode of the distribution, or simply a set of samples drawn from the distribution. In this paper, we describe connections this research area called \Probabilistic Programming" has with programming languages and software engineering, and this includes language design, and the static and dynamic analysis of programs. We survey current state of the art and speculate on promising directions for future research
PSPACE-completeness of Modular Supervisory Control Problems*
In this paper we investigate computational issues associated with the supervision of concurrent processes modeled as modular discrete-event systems. Here, modular discrete-event systems are sets of deterministic finite-state automata whose interaction is modeled by the parallel composition operation. Even with such a simple model process model, we show that in general many problems related to the supervision of these systems are PSPACE-complete. This shows that although there may be space-efficient methods for avoiding the state-explosion problem inherent to concurrent processes, there are most likely no time-efficient solutions that would aid in the study of such “large-scale” systems. We show our results using a reduction from a special class of automata intersection problem introduced here where behavior is assumed to be prefix-closed. We find that deciding if there exists a supervisor for a modular system to achieve a global specification is PSPACE-complete. We also show many verification problems for system supervision are PSPACE-complete, even for prefix-closed cases. Supervisor admissibility and online supervision operations are also discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45090/1/10626_2004_Article_6210.pd
Perturbation analysis of stochastic hybrid systems and applications to resource contention games
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