Reduced Complexity Filtering with Stochastic Dominance Bounds: A Convex Optimization Approach

This paper uses stochastic dominance principles to construct upper and lower sample path bounds for Hidden Markov Model (HMM) filters. Given a HMM, by using convex optimization methods for nuclear norm minimization with copositive constraints, we construct low rank stochastic marices so that the optimal filters using these matrices provably lower and upper bound (with respect to a partially ordered set) the true filtered distribution at each time instant. Since these matrices are low rank (say R), the computational cost of evaluating the filtering bounds is O(XR) instead of O(X2). A Monte-Carlo importance sampling filter is presented that exploits these upper and lower bounds to estimate the optimal posterior. Finally, using the Dobrushin coefficient, explicit bounds are given on the variational norm between the true posterior and the upper and lower bounds

Exact Dipole Radiation for an Oblate Spheroidal Cavity Filled With Isorefractive Material and Aperture-Coupled to a Half Space

Abstract-An oblate semi-spheroidal cavity flush-mounted under a metal plane and coupled to the half-space above it via its circular interfocal aperture is considered. The cavity is filled with a material isorefractive to the medium that occupies the half-space above it. An exact solution is obtained for the radiation of an electric or magnetic dipole located on the symmetry axis of the structure, either outside or inside the cavity, and axially oriented. Numerical results are provided

An algorithm for computing the staircase form of a system pencil and related geometric aspects

In this paper we propose a new recursive algorithm for computing the staircase form of a matrix pencil, and implicitly its Kronecker structure. The algorithm compares favorably to existing ones in terms of elegance, versatility, and complexity. In particular, the algorithm without any modification yields the structural invariants associated with a generalized state-space system and its system pencil. Two related geometric aspects are also discussed: we show that an appropriate choice of a set of nested spaces related to the pencil leads directly to the staircase form; and we extend the notion of deflating subspace to the singular pencil cas

The Best Approximation of the Field Effects in Electric Circuit Coupled Problems

The paper presents a new efficient technique to solve electromagnetic field problems coupled with electric or electronic circuits. It is based on a post-processing algorithm which extracts from the numerical field solution a lumped parameters circuit with imposed complexity, ensuring minimal approximation error. In order to evaluate the algorithm's accuracy a general theory regarding equivalent circuits for quasistationary field effects was developed. The new technique was applied and errors were evaluated in two simple but relevant cases. A practical application (the FLUXSET sensor modeling) is also presented. Index terms---Eddy currents, distributed parameter circuits, approximation methods, identification, magnetic circuits, magnetic field detector, electromagnetic circuit element. I. Introduction In electrical engineering more than often interest is focused on the analysis and design of the electromagnetic devices with field effects (eddy currents, skin effects) which are connecte..

© 2019 Copyright held by the owner/author(s). Publication rights licensed to ACM.

We investigate the use of coverage-guided fuzzing as a means ofproving satisfiability of SMT formulas over finite variable domains,with specific application to floating-point constraints. We show howan SMT formula can be encoded as a program containing a locationthat is reachable if and only if the program’s input corresponds toa satisfying assignment to the formula. A coverage-guided fuzzercan then be used to search for an input that reaches the location,yielding a satisfying assignment. We have implemented this ideain a tool,JustFuzz-itSolver (JFS), and we present a large experi-mental evaluation showing that JFS is both competitive with andcomplementary to state-of-the-art SMT solvers with respect tosolving floating-point constraints, and that the coverage-guidedapproach of JFS provides significant benefit over naive fuzzing inthe floating-point domain. Applied in a portfolio manner, the JFS approach thus has the potential to complement traditional SMTsolvers for program analysis tasks that involve reasoning aboutfloating-point constraints

CRESON: Callable and Replicated Shared Objects over NoSQL

Abstract: In a Cloud environment, the ability to share and persist objects simplifies the design of applications. Storing objects in a NoSQL database ensures their availability and provides scalability to applications. When Object-NoSQL Mapping is performed at the client side, objects that are accessed by several clients are repeatedly converted between their in-memory and serialized representations. This negatively impacts performance and increases replication costs. In this paper, we describe the design of CRESON, a system supporting callable objects over NoSQL, in which application objects are mapped and instantiated directly on the storage nodes. CRESON supports composition by reference and ensures strong consistency. Objects are replicated and maintained coherent using State Machine Replication. The implementation of CRESON leverages the support of a listenable key-value store (LKVS), a novel NoSQL storage abstraction that we introduce in this paper. We discuss the performance and complexity of CRESON with the example of the portage of a personal cloud storage service, initially developed using an object-relational mapping over a sharded PostgreSQL database. Our results show that CRESON offers a simpler programming experience both in terms of learning time and lines of code, while performing better on average and being more scalable