306 research outputs found
Latent parameter estimation in fusion networks using separable likelihoods
Multi-sensor state space models underpin fusion applications in networks of
sensors. Estimation of latent parameters in these models has the potential to
provide highly desirable capabilities such as network self-calibration.
Conventional solutions to the problem pose difficulties in scaling with the
number of sensors due to the joint multi-sensor filtering involved when
evaluating the parameter likelihood. In this article, we propose a separable
pseudo-likelihood which is a more accurate approximation compared to a
previously proposed alternative under typical operating conditions. In
addition, we consider using separable likelihoods in the presence of many
objects and ambiguity in associating measurements with objects that originated
them. To this end, we use a state space model with a hypothesis based
parameterisation, and, develop an empirical Bayesian perspective in order to
evaluate separable likelihoods on this model using local filtering. Bayesian
inference with this likelihood is carried out using belief propagation on the
associated pairwise Markov random field. We specify a particle algorithm for
latent parameter estimation in a linear Gaussian state space model and
demonstrate its efficacy for network self-calibration using measurements from
non-cooperative targets in comparison with alternatives.Comment: accepted with minor revisions, IEEE Transactions on Signal and
Information Processing Over Network
A Microprocessor-based multivariable interactive control system
This study outlines the various types of control systems and reviews the necessary mathematical techniques to solve the problem of multivariable interactive control. The characteristics as well as the state representation for control processes involving either p or v type canonical structures are discussed. Next, the characteristics of multivariable interactive discrete control systems are discussed in detail. The advantages of flexibility and speed of microprocessors are used as powerful tools to implement a microprocessor-based system can be employed to control discrete processes. To demonstrate a practical application of a microprocessor-based system in a multivariable interactive discrete process, the algorithm and software (Assembly Language) is developed for a special engine control system selected as the model
Road vehicle state estimation using low-cost GPS/INS
Due to noise and bias in the Inertial Navigation System (INS), vehicle dynamics
measurements using the INS are inaccurate. Although alternative methods involving
the integration of INS with accurate Global Positioning System (GPS) exist and
are accurate, this kind of system is far too expensive to become value-adding to
production vehicles. This thesis therefore considers two aspects: 1) the possibility
of estimating vehicle dynamics using low-cost INS and GPS, and 2) the importance
of vehicle dynamics in terms of handling in the eyes of customers upon vehicle
purchase. The former aspect is considered from an engineering perspective and the
latter is studied in a marketing context.
From an engineering point of view, knowledge of vehicle dynamics not only improves
existing safety control systems, such the Anti-lock Braking System (ABS)
and Electronic Stabilising Program (ESP), but also allows the development of new
systems. Based on modelling and simulation in MATLAB/Simulink, low-cost GPS
and in-car INS (such as accelerometers, gyroscopes and wheel speed sensors) measurements
are fused using Kalman Filters (KFs) to estimate the vehicle dynamics.
These estimations are then compared with the simulation results from IPG Car-
Maker. For most simulations, the speed of the vehicle is kept between 15 to 55kph.
It is found that while triple KF designs are able to estimate the tyre radius, the
longitudinal velocity and the heading angle accurately, an integrated KF design
with known vehicle parameters is also able to estimate the lateral velocity precisely.
Apart from studying and comparing different KF designs with restricted sensors
quality, the effects and benefits of different sensor qualities in dynamic estimations
are also studied via the variation of sensor sampling rates and accuracies. This investigation
produces a design procedure and estimation error analyses (theoretical
and graphical) which may help future engineers in designing their KFs.
From a marketing perspective, it is important to understand customers’ purchase
reasons in order to allocate resources more efficiently and effectively. As GPS/INS
KF designs are able to enhance vehicle handling, it is vital to understand the relative
importance of vehicle handling as a consumer purchase choice criterion. Based on two surveys, namely the New Vehicle Experience Survey in the US (NVES US)
and the New Car Buyer Survey in the UK (NCBS UK), analyses are performed in a
computer program called the Predictive Analytics SoftWare (PASW), which is formerly
known as the Statistical Package for the Social Sciences (SPSS). The number
of purchase reasons are first reduced with factor analysis, the latent factors produced
are then used in the SPSS Two Step Cluster analysis for customer segmentation.
With the customer segments and the latent factors defined, a discriminant analysis
is carried out to determine customer type in the automobile sector, in particular for
Jaguar Cars. It is found that customers in general take vehicle handling for granted
and often underrate its importance in their purchase. New vehicle handling-aided
systems therefore need to be marketed in terms of the value they add to other benefits
such as reliability and performance in order to increase sales and stakeholder
value
NASA Tech Briefs, November 1994
Topics: Advanced Manufacturing; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports
De productie en moleculaire verschijningsvorm van radiotoxisch Po-210 in kernfusie- en splijtingsreactoren = The Production and Molecular Occurrence of Radiotoxic Po-210 in Nuclear Fusion and Fission Reactors
In order to counter the climate change, there is a need for a radical revolution in the global energy supply. One of the most realistic scenarios is a substantial shift towards renewable energy sources, supported by a flexible baseload from carbon-free nuclear energy. The main requirements for this new generation of nuclear reactors are intrinsic safety, high fuel efficiency and a minimum amount of (long-lived) radioactive waste. A promising candidate for the near future is the lead (alloy) cooled fast fission reactor. An ideal long-term solution are nuclear fusion reactors, which produce only a small amount of short-lived radioactive waste. A problem that occurs in both these reactor types is the undesired production of the highly radiotoxic polonium-210 isotope. In this PhD thesis, the total production of this isotope in a nuclear fusion reactor is determined using neutron transport and inventory calculations. Next, quantum chemical calculations are performed to predict the molecular form in which Po-210 will occur in both discussed reactor types. Combining both aspects allows to estimate the risk associated with the presence of Po-210 in a nuclear reactor and can help to design efficient Po-210 extraction systems
Beyond 100: The Next Century in Geodesy
This open access book contains 30 peer-reviewed papers based on presentations at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). The meeting was held from July 8 to 18, 2019 in Montreal, Canada, with the theme being the celebration of the centennial of the establishment of the IUGG. The centennial was also a good opportunity to look forward to the next century, as reflected in the title of this volume. The papers in this volume represent a cross-section of present activity in geodesy, and highlight the future directions in the field as we begin the second century of the IUGG. During the meeting, the International Association of Geodesy (IAG) organized one Union Symposium, 6 IAG Symposia, 7 Joint Symposia with other associations, and 20 business meetings. In addition, IAG co-sponsored 8 Union Symposia and 15 Joint Symposia. In total, 3952 participants registered, 437 of them with IAG priority. In total, there were 234 symposia and 18 Workshops with 4580 presentations, of which 469 were in IAG-associated symposia. ; This volume will publish papers based on International Association of Geodesy (IAG) -related presentations made at the International Association of Geodesy at the 27th IUGG General Assembly, Montreal, July 2019. It will include papers associated with all of the IAG and joint symposia from the meeting, which span all aspects of modern geodesy, and linkages to earth and environmental sciences. It continues the long-running IAG Symposia Series
Beyond 100: The Next Century in Geodesy
This open access book contains 30 peer-reviewed papers based on presentations at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). The meeting was held from July 8 to 18, 2019 in Montreal, Canada, with the theme being the celebration of the centennial of the establishment of the IUGG. The centennial was also a good opportunity to look forward to the next century, as reflected in the title of this volume. The papers in this volume represent a cross-section of present activity in geodesy, and highlight the future directions in the field as we begin the second century of the IUGG. During the meeting, the International Association of Geodesy (IAG) organized one Union Symposium, 6 IAG Symposia, 7 Joint Symposia with other associations, and 20 business meetings. In addition, IAG co-sponsored 8 Union Symposia and 15 Joint Symposia. In total, 3952 participants registered, 437 of them with IAG priority. In total, there were 234 symposia and 18 Workshops with 4580 presentations, of which 469 were in IAG-associated symposia. ; This volume will publish papers based on International Association of Geodesy (IAG) -related presentations made at the International Association of Geodesy at the 27th IUGG General Assembly, Montreal, July 2019. It will include papers associated with all of the IAG and joint symposia from the meeting, which span all aspects of modern geodesy, and linkages to earth and environmental sciences. It continues the long-running IAG Symposia Series
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