116,005 research outputs found
Automatic computation of data-set definitions
Mathematical method for the construction of a computer program data set description from a computer program contains detailed declarative information. Cartesian products and disjoint-union operators are used to yield a series of recursive group equations
Kalman Filtering Over a Packet-Dropping Network: A Probabilistic Perspective
We consider the problem of state estimation of a discrete time process over a packet-dropping network. Previous work on Kalman filtering with intermittent observations is concerned with the asymptotic behavior of E[P_k], i.e., the expected value of the error covariance, for a given packet arrival rate. We consider a different performance metric, Pr[P_k ≤ M], i.e., the probability that P_k is bounded by a given M. We consider two scenarios in the paper. In the first scenario, when the sensor sends its measurement data to the remote estimator via a packet-dropping network, we derive lower and upper bounds on Pr[P_k ≤ M]. In the second scenario, when the sensor preprocesses the measurement data and sends its local state estimate to the estimator, we show that the previously derived lower and upper bounds are equal to each other, hence we are able to provide a closed form expression for Pr[P_k ≤ M]. We also recover the results in the literature when using Pr[P_k ≤ M] as a metric for scalar systems. Examples are provided to illustrate the theory developed in the paper
Deliverable JRA1.1: Evaluation of current network control and management planes for multi-domain network infrastructure
This deliverable includes a compilation and evaluation of available control and management architectures and protocols applicable to a multilayer infrastructure in a multi-domain Virtual Network environment.The scope of this deliverable is mainly focused on the virtualisation of the resources within a network and at processing nodes. The virtualization of the FEDERICA infrastructure allows the provisioning of its available resources to users by means of FEDERICA slices. A slice is seen by the user as a real physical network under his/her domain, however it maps to a logical partition (a virtual instance) of the physical FEDERICA resources. A slice is built to exhibit to the highest degree all the principles applicable to a physical network (isolation, reproducibility, manageability, ...). Currently, there are no standard definitions available for network virtualization or its associated architectures. Therefore, this deliverable proposes the Virtual Network layer architecture and evaluates a set of Management- and Control Planes that can be used for the partitioning and virtualization of the FEDERICA network resources. This evaluation has been performed taking into account an initial set of FEDERICA requirements; a possible extension of the selected tools will be evaluated in future deliverables. The studies described in this deliverable define the virtual architecture of the FEDERICA infrastructure. During this activity, the need has been recognised to establish a new set of basic definitions (taxonomy) for the building blocks that compose the so-called slice, i.e. the virtual network instantiation (which is virtual with regard to the abstracted view made of the building blocks of the FEDERICA infrastructure) and its architectural plane representation. These definitions will be established as a common nomenclature for the FEDERICA project. Other important aspects when defining a new architecture are the user requirements. It is crucial that the resulting architecture fits the demands that users may have. Since this deliverable has been produced at the same time as the contact process with users, made by the project activities related to the Use Case definitions, JRA1 has proposed a set of basic Use Cases to be considered as starting point for its internal studies. When researchers want to experiment with their developments, they need not only network resources on their slices, but also a slice of the processing resources. These processing slice resources are understood as virtual machine instances that users can use to make them behave as software routers or end nodes, on which to download the software protocols or applications they have produced and want to assess in a realistic environment. Hence, this deliverable also studies the APIs of several virtual machine management software products in order to identify which best suits FEDERICA’s needs.Postprint (published version
Model Creation and Equivalence Proofs of Cellular Automata and Artificial Neural Networks
Computational methods and mathematical models have invaded arguably every
scientific discipline forming its own field of research called computational
science. Mathematical models are the theoretical foundation of computational
science. Since Newton's time, differential equations in mathematical models
have been widely and successfully used to describe the macroscopic or global
behaviour of systems. With spatially inhomogeneous, time-varying, local
element-specific, and often non-linear interactions, the dynamics of complex
systems is in contrast more efficiently described by local rules and thus in an
algorithmic and local or microscopic manner. The theory of mathematical
modelling taking into account these characteristics of complex systems has to
be established still. We recently presented a so-called allagmatic method
including a system metamodel to provide a framework for describing, modelling,
simulating, and interpreting complex systems. Implementations of cellular
automata and artificial neural networks were described and created with that
method. Guidance from philosophy were helpful in these first studies focusing
on programming and feasibility. A rigorous mathematical formalism, however, is
still missing. This would not only more precisely describe and define the
system metamodel, it would also further generalise it and with that extend its
reach to formal treatment in applied mathematics and theoretical aspects of
computational science as well as extend its applicability to other mathematical
and computational models such as agent-based models. Here, a mathematical
definition of the system metamodel is provided. Based on the presented
formalism, model creation and equivalence of cellular automata and artificial
neural networks are proved. It thus provides a formal approach for studying the
creation of mathematical models as well as their structural and operational
comparison.Comment: 13 pages, 1 tabl
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