Proceedings of the EAA Spatial Audio Signal Processing symposium: SASP 2019

International audienc

Applications of numerical analysis in navigation

Part one of the thesis contains analysis of the methods of computation in navigation. We start with loxodromic navigation and, although this subject is well documented, we make a positive attempt to analyse the subject matter using the methods of differential geometry. We then turn to the problem of shortest path curves and set out an alternative method of solving the problem of navigating along the arc of a great circle on the surface of a sphere which can be generalised to other surfaces. In particular, a contribution made by the thesis is an analysis of the problem of navigating along shortest path geodesic arcs on the surface of a spheroid which introduces an algebraic representation of the geodesic curve by solving Clairaut' s equation using a cylindrical transformation. We are therefore able to compute the the coordinates of the positions of points along the path of the geodesic and the length of arc along the path of the. geodesic curve can then be computed step by step between these points by a numerical method - the Direct Cubic Spline method which was first introduced by this author in the Bachelor of Philosophy thesis in 1982 and is developed further in part 2 of this thesis. We apply this method also to the special problem of computing the distance along the shortest path between nearly antipodean points on the surface of a spheroid. We analyse the problem of computing an observer's position on the surface of the Earth using astronomical observations and show how a position locus is distorted when it is transferred over the surface. We offer a method of computing the observer's position by a series of observations of a single astronomical body taken over a comparitively short period of time and which does not necessarily include an observation at the tide of meridian passage of the body. In part two of the thesis we discuss the Direct Spline approximation to integrals and give some error bounds. The Direct Cubic Spline is a step by step method of fitting a cubic spline to the integral of a function directly which computes the value of the integral of the function step by step between the data points which need not be evenly spaced. We extend the idea to splines of higher order and give the formula from which they may be obtained but we show that, except for a particular special form of the direct quartic spline. the higher order direct splines do not yield algorithm for computing integrals which are as efficient as the Direct Cubic Spline

The limit equilibrium method of slope stability analysis

Imperial Users onl

Horizon definition study summary - Horizon definition study

Earth infrared horizon definition for space guidance, navigation, control, and pointing systems - feasibility stud

Literature review of the remote sensing of natural resources

Abstracts of 596 documents related to remote sensors or the remote sensing of natural resources by satellite, aircraft, or ground-based stations are presented. Topics covered include general theory, geology and hydrology, agriculture and forestry, marine sciences, urban land use, and instrumentation. Recent documents not yet cited in any of the seven information sources used for the compilation are summarized. An author/key word index is provided

Machine Learning Econometrics

Much of econometrics is based on a tight probabilistic approach to empirical modeling that dates back to Haavelmo (1944). This thesis explores a modern algorithmic view, and by doing so, finds solutions to classic problems while developing new avenues. In the first chapter, Kalman-filter based computations of random walk coefficients are replaced by a closed-form solution only second to least squares in the pantheon of simplicity. In the second chapter, random walk “drifting” coefficients are themselves dismissed. Rather, evolving coefficients are modeled and forecasted with a powerful machine learning algorithm. Conveniently, this generalization of time-varying parameters provides statistical efficiency and interpretability, which off-the-shelf machine learning algorithms cannot easily offer. The third chapter is about the to the fundamental problem of detecting at which point a learner stops learning and starts imitating. It answers “why can’t Random Forest overfit?” The phenomenon is shown to be a surprising byproduct of randomized “greedy” algorithms – often deployed in the face of computational adversity. Then, the insights are utilized to develop new high-performing non-overfitting algorithms

Feasibility study for a Scanning Celestial Attitude Determination System /SCADS/ for three axis attitude determination at a Command and Data Acquisition /CDA/ station Final report

Scanning Celestial Attitude Determination System /SCADS/ for three axis attitude determination at Command and Data Acquisition /CDA/ statio

Environmental Impact Assessment by Green Processes

Primary energy consumption around the world has been increasing steadily since the Industrial Revolution and shows no signals of slowing down in the coming years. This trend is accompanied by the increasing pollutant concentration on the Earth’s biosystems and the general concerns over the health and environmental impacts that will ensue. Air quality, water purity, atmospheric CO2 concentration, etc., are some examples of environmental parameters that are degrading due to human activities. These ecosystems can be safeguarded without renouncing industrial development, urban and economic development through the use of low environmental impact technologies instead of equivalent pollutant ones or through the use of technologies to mitigate the negative impact of high emissions technologies. Pollutant abatement systems, carbon capture technologies, biobased products, etc. need to be established in order to make environmental parameters more and more similar to the pre-industrialization values of the planet Earth. In 15 papers international scientists addressed such topics, especially combining a high academic standard coupled with a practical focus on green processes and a quantitative approach to environmental impacts

Catalytic steam reformer tubes non-destructive inspection technology investigation and advancement : a dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Manawatu Campus, New Zealand

Catalytic Steam reforming is a chemical synthesis process used in the production of hydrogen by mixing hydrocarbon with steam in the presence of a metal-based catalyst. This is achieved in a steam reformer plant where the mixture of gases is elevated to high pressure and temperature through a continuous process for efficient mass production of syngas to meet the global hydrogen demand. One of the challenges in operating a steam reformer plant is monitoring and maintaining the tubular reactors (Reformer tube). Under the severe service conditions the tubes a subjected to various degradation mechanism which ultimately determine the service life. With the tubes accounting to over 20% of the capital cost of a reformer plant, it is of great significance to maximise the service life of each tubes, which has been the motivation to the advancement in metallurgy and NDT technology around reformer tubes from the introduction of Catalytic Steam reforming in the early 20th century. Under the influence of long-term exposure of mechanical stressing and elevated temperature, reformer tube is subjected to a material degrading phenomenon call creep deformation. In 1952, F.R. Larson and J. Miller devised the Larson-Miller Parameter which predicts the lifetime of a material based on service temperature and stress-rupture time and for decades this method was used design and managed reformer tubes on a time-based strategy of 10,000 service hour. However, case studies have time and time shown premature rupture of reformer tube causing unexpected downtime resulting in significant loss in production and asset. Hence engineers and researchers have worked on a more direct method of assessing the remaining service life of reformer tubes. Inline pipe inspection is a hot area of research in robotics and automation. Eddy current, laser profilometry, ultrasonic and infrared thermography is the four technology that is currently dominating the Reformer industry, of which laser profilometry assessment being the only method capable of early stage creep detection. While other fields of pipe inspection have advanced and industrially applied over past decades, it is the author's opinion that NDT technology for reformer tube is outdated with areas of innovation. The aim of this research is to investigate an alternative solution to overcome the challenges and limited faced in modern systems and contribute to the advancement of NDT of Catalytic Steam reformer tubes. Presented in this dissertation is a new framework for an autonomous Reformer Tube inspection system, which incorporates a number of innovative elements for improved creep damage assessment. The program for this work is comprised of three studies. In the first study, the challenges around process profilometry dataset is demonstrated, the limitation in the available methods is discussed, and the impacts in regards to detection creep deformation is identified. Based on the finding, a three-stage creep detection algorithm (CDA) is derived, offering a dynamic solution to distinguish two modes of isotropic and anisotropic creep deformation. The system is experimentally assessed using a set of profilometry measurements collected from retire reformer tube. In the second study, a novel method for tracking a motion of an object moving inside a reformer tube is devised. Literature study showed that conventional profilometry system suffers from measurement uncertainty cause from an uncontrolled rotation of measurement instruction during an inspection. Because location information gives valuable insight as to the performance of the plant, the long-range optic solution is conceptualised, based on polarising filters and Malus Law, to overcome these limitations. In this research, a proof of concept experiment is conducted to evaluate and justify the conceptual method through the development of a working prototype. This novel technique is named Optical Position Tracking (OPT) system. Presented in the final study is an autonomous reformer tube inspection system developed on the basis of the results and finding in the first portion of the research. The contribution of this research is demonstrated with a working prototype justifying the practicality of CDA and the OPT system. The design incorporates wireless communication, modular design, and modern semiconductor sensing technology. In conclusion, this research met the first milestone for an ongoing research to progress the NTD industry