1,028 research outputs found
Conditions for suboptimal filter stability in SLAM
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2004, Sendai (Japón)In this article, we show marginal stability in SLAM, guaranteeing convergence to a non-zero mean state error estimate bounded by a constant value. Moreover, marginal stability guarantees also convergence of the Riccati equation of the one-step ahead state error covariance to at least one psd steady state solution. In the search for real time implementations of SLAM, covariance inflation methods produce a suboptimal filter that eventually may lead to the computation of an unbounded state error covariance. We provide tight constraints in the amount of decorrelation possible, to guarantee convergence of the state error covariance, and at the same time, a linear-time implementation of SLAM.This work was supported by the project 'Supervised learning of industrial scenes by means of an active vision equipped mobile robot.' (J-00063).Peer Reviewe
Discrimination of Dynamical System Models for Biological and Chemical Processes
In technical chemistry, systems biology and biotechnology, the construction of predictive models has become
an essential step in process design and product optimization. Accurate modelling of the reactions requires detailed
knowledge about the processes involved. However, when concerned with the development of new products and production
techniques for example, this knowledge often is not available due to the lack of experimental data. Thus, when one has
to work with a selection of proposed models, the main tasks of early development is to discriminate these models. In this
article, a new statistical approach to model discrimination is described that ranks models wrt. the probability with which
they reproduce the given data. The article introduces the new approach, discusses its statistical background, presents
numerical techniques for its implementation and illustrates the application to examples from biokinetics
Development of Acid-Sensitive Platinum(II) Complexes With Protein-Binding Properties
Four new protein-binding platinum(II) complexes, 10, 11, 21, 22, in which the dichloroplatinum moiety is coordinated either to a carbon-substituted or a nitrogen-substituted ethylene diamino ligand, were prepared in ten-step syntheses. According to pH-dependent stability studies with strictly related compounds, 11 and 22 exhibit acid-sensitive properties
Verified and potential pathogens of predatory mites (Acari: Phytoseiidae)
Several species of phytoseiid mites (Acari: Phytoseiidae), including species of the genera Amblyseius, Galendromus, Metaseiulus, Neoseiulus, Phytoseiulus and Typhlodromus, are currently reared for biological control of various crop pests and/or as model organisms for the study of predator¿prey interactions. Pathogen-free phytoseiid mites are important to obtain high efficacy in biological pest control and to get reliable data in mite research, as pathogens may affect the performance of their host or alter their reproduction and behaviour. Potential and verified pathogens have been reported for phytoseiid mites during the past 25 years. The present review provides an overview, including potential pathogens with unknown host effects (17 reports), endosymbiotic Wolbachia (seven reports), other bacteria (including Cardinium and Spiroplasma) (four reports), cases of unidentified diseases (three reports) and cases of verified pathogens (six reports). From the latter group four reports refer to Microsporidia, one to a fungus and one to a bacterium. Only five entities have been studied in detail, including Wolbachia infecting seven predatory mite species, other endosymbiotic bacteria infecting Metaseiulus (Galendromus, Typhlodromus) occidentalis (Nesbitt), the bacterium Acaricomes phytoseiuli infecting Phytoseiulus persimilis Athias-Henriot, the microsporidium Microsporidium phytoseiuli infecting P. persimilis and the microsporidium Oligosproridium occidentalis infecting M. occidentalis. In four cases (Wolbachia, A. phytoseiuli, M. phytoseiuli and O. occidentalis) an infection may be connected with fitness costs of the host. Moreover, infection is not always readily visible as no obvious gross symptoms are present. Monitoring of these entities on a routine and continuous basis should therefore get more attention, especially in commercial mass-production. Special attention should be paid to field-collected mites before introduction into the laboratory or mass rearing, and to mites that are exchanged among rearing facilities. However, at present general pathogen monitoring is not yet practical as effects of many entities are unknown. More research effort is needed concerning verified and potential pathogens of commercially reared arthropods and those used as model organisms in research
Estimating Kinetic Parameters for the Spontaneous Polymerization of Glycidol at Elevated Temperatures
The ring-opening polymerization of glycidol at elevated temperatures is investigated. To
improve the synthesis of dendritic polyether polyols, experiments are carried out without
initiator to identify the influence of thermal side reactions. This results in a step-growth
polymerization caused by the spontaneous combination
of monomers. Kinetic parameters of the
side reactions are estimated by fitting simulated
number- and weight-average molecular weights
to the experimental values measured at different
reaction times during the polymerization. The
reactions are conducted at three different temperatures
of 90, 105, and 120 8C. It is shown that
thermal side reactions lead to high dispersities of
the final product and are highly sensitive to the
reactor operating temperature
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