Intelligent joint channel parameter estimation techniques for mobile wireless positioning applications

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Mobile wireless positioning has recently received great attention. For mobile wireless communication networks, an inherently suitable approach is to obtain the parameters that are used for positioning estimates from the radio signal measurements between a mobile device and one or more xed base stations. However, obtaining accurate estimates of these location-dependent channel parameters is a challenging task. The focus of this thesis is on the estimation of these channel parameters for mobile wireless positioning applications. In particular, we investigate novel estimators that jointly estimate more than one type of channel parameters. We rst perform a comprehensive critical review on the most recent and popular joint channel parameter estimation techniques. Secondly, we improve a state-of-the-art technique, namely the Space Alternating Generalised Expectation maximisation (SAGE) algorithm by employing adaptive interference cancellation to improve the estimation accuracy of weaker paths. Thirdly, a novel intelligent channel parameter estimation technique using Evolution Strategy (ES) is proposed to overcome the drawbacks of the existing iterative maximum likelihood methods. Furthermore, given that in reality it is di cult to obtain the number of multipath in advance, we propose a two tier Hierarchically Organised ES to jointly estimate the number of multipath as well as the channel parameters. Finally, we extend the proposed ES method to further estimate the Doppler shift in mobile environments. Our proposed intelligent joint channel estimation techniques are shown to exhibit excellent performance even with low Signal to Noise Ratio (SNR) channel conditions as well as robust against uncertainties in initialisations.EPSRC and Cambridge Silicon Radi

Ottimizzazione delle prestazioni energetiche dell'involucro edilizio per l'esposizione solare.

Nel corso del Dottorato di Ricerca in Energetica Elettrica e Termica (XXIV ciclo) il sottoscritto ha approfondito tematiche relative al comportamento termico degli edifici e al risparmio energetico in edilizia, con particolare riferimento all'ottimizzazione delle prestazioni energetiche dell'involucro edilizio. L'attività è stata svolta all'interno del gruppo di Fisica Tecnica Ambientale del Dipartimento di Ingegneria dell'Energia e dei Sistemi (DESE) dell'Università di Pisa. I temi trattati, volti all'ottimizzazione dell’involucro nei suoi diversi aspetti, sono stati in particolare i seguenti. Studio dei parametri, trasmittanza termica dinamica Yie e ritardo temporale t, caratterizzanti il comportamento in condizioni non stazionarie delle pareti esterne opache, anche con riferimento ai più recenti sviluppi normativi. Sviluppo di un programma di calcolo, adatto per applicazioni progettuali, per valutare i parametri trasmittanza termica dinamica Yie e ritardo temporale t di pareti e coperture opache in condizioni di regime termico periodico. Studio del raffrescamento passivo degli edifici con l'impiego di facciate e coperture ventilate e sviluppo di un programma di calcolo, adatto per applicazioni progettuali, per valutare i parametri caratterizzanti il comportamento in condizioni di regime termico stazionarie di pareti e coperture ventilate. Sviluppo di un programma di calcolo per valutare il comportamento termico dinamico di pareti e coperture ventilate, anche in relazione alle soluzioni tecniche conformi precisare nella normativa. Studio dell'ottimizzazione della percentuale di superficie finestrata dell'involucro edilizio e dell'uso di serre solari addossate, facendo uso di un edificio test. Di tale edificio sono state studiate le prestazioni energetiche e le corrispondenti variazioni al variare della localizzazione geografica, della percentuale di superficie finestrata e dell'uso di una serra solare. Studio dell'esposizione solare dell'involucro edilizio, allo scopo di individuare le forme e le superfici ideali di involucro che permettano di massimizzare o minimizzare l'apporto energetico dovuto all'irraggiamento solare, con metodi variazionali. Ottimizzazione della forma dell'edificio per l'esposizione solare e i consumi energetici ad esso associati, con metodo numerico basato su Algoritmi Evolutivi. Tale attività è stata svolta, per un semestre come exchange doctoral students, presso l'École Polytechnique Fédérale de Lausanne

Hierarchically organised evolution strategies on the parabolic ridge

Organising evolution strategies hierarchically has been proposed as a means for adapting strategy parameters such as step lengths. Experimental research has shown that on ridge functions, hierarchically organised strategies can significantly outperform strategies that rely on mutative selfadaptation. This paper presents a first theoretical analysis of the behaviour of a hierarchically organised evolution strategy. Quantitative results are derived for the parabolic ridge that describe the dependence on the length of the isolation periods of the mutation strength and the progress rate. The issue of choosing an appropriate length of the isolation periods is discussed and comparisons with recent results for cumulative step length adaptation are drawn

On the modelling and optimisation of urban energy fluxes

Around 3/4 of global resources are currently consumed in urban settlements, with corresponding adverse environmental consequences. According to population forecasts this situation will worsen in the coming years. It is therefore imperative that we understand how to design less resource intensive urban settlements. Software for the modelling and optimisation of resource flows are of interest to support urban designers in achieving this objective. To this end we have, in the first instance, tackled the problem of optimising the layout and form of buildings for the utilisation of solar radiation by using a multi-objective evolutionary algorithm. This new methodology facilitates a considerably more exhaustive search of the parameter space than manual trial and error which has been favoured in past studies. However, multi-objective optimisers involve many redundant evaluations when only one objective (the energy consumption) and analytical constraints (the volume of the urban form has to remain within bounds) are taken into account. To resolve this, we developed a new evolutionary algorithm that avoids evaluations of potential solutions that violate constraints. This is a hybrid based of the CMA-ES and HDE evolutionary algorithms. This hybrid algorithm achieves 100% convergence to the global minimum relating to two highly multi-modal benchmark functions and good results compared to the multi-objective evolutionary algorithm previously used and to a hybrid of heuristic and direct search methods (PSO/HJ) for real-world problems. Key contributions have also been made to the development of a new urban energy modelling tool: CitySim. These contributions include a mono and multi-zone thermal model, which is linked to an HVAC model that takes into account the increased energy demands due to the use of air as medium for heating, cooling and fresh air supply. In order to complete the provision of heating/cooling as well as electricity, the most commonly used energy conversion systems are modelled. Outputs from these systems may also be coupled with a model of sensible/latent heat storage. Finally the new hybrid evolutionary algorithm was used to optimise the energy performance of a case study of 26 buildings in the Matthäus district (Basel) using CitySim as the energy modelling tool. The results indicated that air conditioning plant should not be necessary in Switzerland if occupants behave appropriately. Concrete strategies for minimising the primary energy demand for the case study were also identified subject to constrained investment capital. This demonstrated that optimally (environmentally) sustainable solutions can be found at the urban scale, to help guide urban designers' decisions