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Counterexamples to general convergence of a commonly used recursive identification method

A recursive algorithm for parametric identification of discrete-time systems known as Panuska's method, the approximate maximum likelihood method or the extended matrix method, is analyzed. Making use of recently developed theory for asymptotic analysis of recursive stochastic algorithms, dynamic systems, and autoregressive moving average (ARMA) processes are constructed for which this algorithm d

Scattering theory and linear least squares estimation : Part I: Continuous-time problems

The Riccati equation plays as important a role in scattering theory as it does in linear least squares estimation theory. However, in the scattering literature, a somewhat different framework of treating the Riccati equation has been developed. This framework is shown to be appropriate for estimation problems and makes possible simple derivations of known results as well as leading to several new

Scattering theory and linear least squares estimation : Part II: Discrete-time problems

A certain "star-product" formalism in scattering theory as developed by Redheffer is shown to also be naturally applicable to discrete-time linear least-squares estimation problems. The formalism seems to provide a nice way of handling some of the well-known algebraic complications of the discrete-time case, e.g., the distinctions between time and measurement updates, predicted and filtered estima

Comments on "A Stochastic Approximation Method"

The results stated in the above paper1 concerning an approved stochastic approximation method are considered. Formulas for the variances of the estimates are derived, and it is found that, in fact, the new algorithm is inferior to previously suggested ones.

Evaluating and Improving Risk Analysis Methods for Critical Systems

At the same time as our dependence on IT systems increases, the number of reports of problems caused by failures of critical IT systems has also increased. Today, almost every societal system or service, e.g., water supply, power supply, transportation, depends on IT systems, and failures of these systems have serious and negative effects on society. In general, public organizations are responsibl

Can the STarT Back Tool predict health-related quality of life and work ability after an acute/subacute episode with back or neck pain? A psychometric validation study in primary care

OBJECTIVES: The predictive ability of the STarT Back Tool (SBT) has not yet been examined among acute/subacute back and/or neck pain in a primary care setting in respect to health-related quality of life (HRQoL) and work ability outcomes. The aim of this study was to evaluate the SBT's predictive validity for HRQoL and work ability outcomes at long-term follow-up in a population with acute/subacut

A WHO-HPH operational program versus usual routines for implementing clinical health promotion : An RCT in health promoting hospitals (HPH)

Background: Implementation of clinical health promotion (CHP) aiming at better health gain is slow despite its effect. CHP focuses on potentially modifiable lifestyle risks such as smoking, alcohol, diet, and physical inactivity. An operational program was created to improve implementation. It included patients, staff, and the organization, and it combined existing standards, indicators, documenta

Scaling our world view : How monoamines can put context into brain circuitry

Monoamines are presumed to be diffuse metabotropic neuromodulators of the topographically and temporally precise ionotropic circuitry which dominates CNS functions. Their malfunction is strongly implicated in motor and cognitive disorders, but their function in behavioral and cognitive processing is scarcely understood. In this paper, the principles of such a monoaminergic function are conceptuali

Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses

Hard x-ray multi-projection imaging for single-shot approaches

High-brilliance x-ray sources (x-ray free-electron lasers or diffraction-limited storage rings) allow the visualization of ultrafast processes in a 2D manner using single exposures. Current 3D approaches scan the sample using multiple exposures, and hence they are not compatible with single-shot acquisitions. Here we propose and verify experimentally an x-ray multi-projection imaging approach, whi