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This study provided evidence of cell-density dependent signalling interactions between the autotrophic ammonia-oxidising bacterium Nitrosomonas europaea and a variety of terrestrial heterotrophic bacteria. The autoinducer signal molecule N-(3-hexanoyl)-L-homoserine lactone (HHL) extended the lag phase of N. europaea recovering from starvation while N-(3-oxooctanoyl)-L-homoserine lactone (OOHL) reduced the lag phase. However, the autoinducers N-(3-oxohexanoyl)-L-homoserine lactone N-(3-oxohexanoyl)-L-homoserine lactone (OHHL), N-(3-oxobutanoyl)-L-homoserine lactone(OBHL) and N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL) did not exert an effect. Spent cell-free medium from early stationary phase cultures of Agrobacterium tumefaciens, Pseudomonas fluorescens and Micrococcus luteus reduced the lag phase of N. europaea recovering from starvation. Supplementing solid medium with spent cell-free medium from the heterotrophs A. tumefaciens, P. fluorescens and M. luteus reduced the incubation period required for the development of colonies of the ammonia-oxidiser. For example, the presence of spent cell-free medium from A. tumefaciens reduced the required incubation period from 20 weeks to 2 weeks. Spent cell-free medium from the heterotrophs Comomonas testosteroni, Erwinia carotovora and Rhizobium leguminosarum had no effect on the growth of N. europaea. A. tumefaciens produces the N-acyl autoinducer OOHL which reduces the lag phase of N. europaea. A mutant unable to produce this autoinducer was generated and spent cell-free medium from this organism had no effect on the recovery of N. europaea from starvation or the incubation period required for the development of colonies of N. europaea on solid medium. Enrichment cultures of ammonia-oxidising bacteria were established from soil and the heterotrophs present in the final stages of enrichment were isolated and identified. Spent cell-free medium from these organisms also reduced the lag phase of N. europaea recovering from starvation and reduced the incubation period required for the development of colonies of N. europaea on solid medium.

This thesis describes the development of a range sensing system. The goal was to create a range sensor that is robust and flexible so that a number of applications within the forest products manufacturing environment can be addressed. Features of the system include: the capability of producing spatially registered image pairs of range and intensity, the ability to generate both range and intensity very quickly, the applicability to a wide variety of industrial applications, the ability to handle large depth-of-field range sensing problems, the ability to do real-time data processing, and the capability to do extensive system diagnostics under complete software control. A triangulation based plane-of-light optical method is employed to extract range information. The research shows that this method suits range sensing applications where conveyor belts are involved. An in-depth study of the triangulation method is included. In the study it shows that this method also supports large depth-of-field range sensing. A dedicated signal processing hardware, built on the Micro Channel interface, performs pipelined image processing and generates range and intensity images in a spatially registered form. The hardware is designed to support several modes of operation, for the purpose of facilitating optical adjustments and calibrations. The hardware self-diagnostic facility is also included in the design. A memory management scheme is provided that facilitates real-time data processing of the range and intensity images. The experiments show that this scheme provides a real-time environment for software processing. This thesis also contains a theory exploring the limitations of the measurement accuracy of the range detection algorithm employed in the prototype system. The maximum data generation rate of the prototype system is 380 range/intensity lines per second at 128 range/intensity pixels per line. Several proposals toward future work are included that aim at improving the speed as well as the measurement accuracy of the prototype system. / Master of Science

This research focuses on developing optical sensing systems for 2D and 3D spatial monitoring of temperature and concentration distribution profiles of complex or reacting gas flows. Non-invasive, species specific and sensitive nature of monitoring allows spatial information to be extracted from harsh environments with poor physical access, allowing validation of computational models or process monitoring. This is suitable for processes like combustion engines or sealed atmospheric cloud chambers. A novel line-of-sight (LOS) Tunable Diode Laser Absorption Spectroscopy(TDLAS) system using a preselected laser diode centred at 7212.88 cm-1 was first designed to monitor the change of relative humidity (water vapour concentration) during an expansion process within the Manchester Ice Cloud Chamber (MICC), operating from atmospheric pressure, down to 0.7 atm. The experimental results were validated with an Aerosol Cloud Precipitation Interaction Model (ACPIM) simulation, feasible for tomography applications. The MICC shares similar combustion monitoring challenges such as minimal optical access or reactive gas flows. The TDLAS system developed for the MICC was then used as a foundation design for a TDLAS tomography setup capable of conducting temporal two-dimensional (2D) and three-dimensional (3D) concentration and temperature imaging. This system uses the principle of two-line thermometry, centred within the near infrared (NIR) region of 7181.93cm-1 and 7179.8 cm-1. The laser was divided into 4 simultaneous parallel beams using a 1 × 4 fiber coupler (4 LOS). Using a motorised platform, the beams were projected at 0.5° interval, from 0° to 179° angle within 3.6 s, around the exhaust of two asymmetrical shaped flame burners. A total of 360 projection slices comprised of 1440 integrated absorbance data were used per tomogram reconstruction. By solving for the spatial distribution of temperature first, the concentration distribution of water vapour could be then calculated. Reconstruction algorithms (Filtered Back Projection, Fourier Slice Reconstruction and Direct Fourier Reconstruction (DFR)) were compared using a range of criteria. The DFR method was selected as the best method at 700 zero padding, with a spatial in-plane resolution of 1-2 lp/cm, pixel resolution of 128 by 128, thermocouple temperature validations of ±5°C and a relative mean error performance of 8.12%. The concentration could not be validated due to the lack of a mass spectrometer.3D volumetric monitoring results took 36 seconds to complete, and was constructed using 10 interpolated parallel, 1 cm height interval spaced tomograms. Independent vertical slices along the x-axis and y-axis could also be extracted. The temporal results were also successfully conducted and consisted of a quick succession of 16 experiments at a temporal resolution of 0.28 frames per second. A tomographic system that performs 3D and 2D temporal sensing was successfully developed and validated. Although 3D work was conducted using planar imaging or hyperspectral tomography, no work has been conducted so far using NIR TDLAS systems to date.

Individual cells in a genetically identical population, exposed to the same environment, can show great variation in their protein expression levels. This is due to noise, which is inherent in many biological processes, due in part to the low molecule numbers and probabilistic interactions which lead to stochasticity. Much of the work in the field of noise and its propagation in gene expression networks, whether it is experimental, modelling or theoretical, has been conducted on networks/systems that occur within a single cell. However, cells do not exist solely in isolation and understanding how cells are able to coordinate their behaviour despite this noise is an interesting area of expansion for the field. In this study, a synthetic intercellular communication system was designed that allows the investigation of how noise is propagated in intercellular communication. The communication system consists of separate sender and receiver cells incorporating components of the Lux quorum sensing system of Vibrio fischeri. The sender cell was designed so that the production of the signalling molecule, 3-oxohexanoyl homoserine lactone, is able to be controlled by addition of isopropyl-β-D-thio-galactoside (IPTG) and monitored via a reporter gene. The receiver cell was designed with a dual reporter system to enable the response of the cell to the signalling molecule to be monitored and the intrinsic and extrinsic noise contributions to the total noise to be calculated. Sender and the receiver cells were engineered in Escherichia coli. The functionality of the receiver cells was tested in the presence of known concentrations of the signalling molecule. The population response and the noise characteristics of the receiver cells in the homogeneous environment were determined from single cell measurements. The functionality of the sender cells was tested in the presence of a range of IPTG concentrations and the induction of expression from the LacI-repressible promoter was monitored. Mathematical models of the system were developed. Stochastic simulations of the models were used to investigate any unexplained behaviour seen in the characterisation of the cells. The full functionality of the intercellular communication system was then tested by growing the receiver in the collected media of the induced sender cells. The response of the receiver cells to the signalling molecule in the media was again characterised using single cell measurements of the reporter expression levels. The analysis of mixed populations of the sender and receiver cells was hampered by the technical limitations of the instruments used for the single cell measurements. Difficulties were encountered in simultaneous and specific measurement of the three reporter genes. Two methods for overcoming this issue were proposed using microscopy, and one of these methods was shown to have potential in overcoming the issue.

<p> With the increased use of the internet, artificial intelligence, IoT, and wearable devices, it has become significantly critical to ensure security and confidentiality of information, particularly within these resource-constrained edge devices. The increased attentions to security and confidentially of information led to the development of computationally-secure cryptographic algorithms. At the same time, low-power sensing devices have emerged as highly promising tools for a wide range of technological applications such as diagnostics, physiological monitoring, and healthcare systems. The desire for seamless and continuous monitoring in sensing applications necessitates these devices to be compact in size and exhibit low power consumption, making them suitable for wearable or portable use with batterypowered operation.</p> <p> Keeping this objective in focus, I will structure this dissertation into the subsequent chapters. The first part (Chapter 2) will cover a theoretical analysis of the proposed Co-planar capacitivE Asymmetry SEnsing (CEASE) technique utilizing four on-die top-layer metal plates. Also, it will present the comparison with other sensing methods which are capacitive parallel and inductive sensing technique in terms of detection range through electromagnetic simulation. The second part (Chapters 3) of this this dissertation will involve explore of the concept of capacitive sensing in an IC layout and co-optimizing both the ground plane capacitance and the sensing capacitance to maximize sensitivity. It will present design of the post-processing circuits and systems with ultra-low power for sensing attacks and to prove the efficacy through the post-layout simulation results. Additionally, integration with digital SCA protection and AES-256 crypto core and checking the efficacy of the proposed method using the integrated detection and countermeasure system in post-layout simulations. Next in Chapter 4, we will show the lowest-power and the energy/conversion step time-based RDC for low frequency applications. It will presents the ways to enhance the energy-resolution trade-offs in time-based RDC, improving the rms jitter/phase noise with help of speed-up latches, to achieve higher bit-resolution. Furthermore, the power/performance trade-off in experiment through 3 different design variations optimized towards lowest energy baseline, higher resolution, and process portability tapeout and IC measurements is presented. Finally, in Chapter 5, we will show a novel proposed switchable dual-mode device that combines a high-frequency antenna and a Human Body Communication (HBC) coupler in a single device. The integration of these two modes addresses the limitations of HBC, such as restricted data transmission, and overcomes the drawbacks of signal absorption in the 24GHz frequency band by the human body. </p>

This thesis reports on the combined effects of toxicants and physicochemical factors on micro-organisms. The main objective of the project was to use multi-sensing systems such as mediated and non-mediated sensor systems, growth tests and physicochemical sensors to investigate novel stressor-toxicant-assay combinations. Screen-printed, disposable, developmental-phase, physicochemical sensor constructs (conductivity and dissolved oxygen) were validated under conditions compatible with microbial bioassays, to ascertain their potential role in toxicity testing. The conductivity sensor construct could be used to indirectly inform on the osmolality of the test samples, but the dissolved oxygen sensor construct was not found to give reproducible results. The results were thought to be compromised by in-house screen-printing using a complex carbon ink formulation for the working electrode. Escherichia coli and a consortium with ammonia oxidation capacity (CAOC) were used as the test species for the bioassays. The combined effects of four inorganic salts (NaCl, NaN03, KCl and KN03) and two toxicants (3,5-DCP and HgCh) on E. coli were investigated using the CellSense™ biosensor system, Clark oxygen electrode and microtitre plate growth assays. A variety of trends were observed with each salt-toxicantbioassay combination, emphasising a need for better understanding of the assay media and factors such as bioavailability, to interpret the toxicity data. The results also suggested the importance of using multiple bioassays with varied end points, for toxicity testing. The CAOC, which was isolated from the activated sludge, was tested for physicochemical stressor and toxicant effects using the mediated biosensors. The results were very different from those obtained with E. coli, indicating that each species reacts to toxicants and changes in physicochemical factors differently. Although the full potential of disposable, physicochemical sensors, at the point of toxicity testing was not achieved, the study did investigate previously uncharacterised, combined effects of salts and toxicants on microbial cells. It highlighted the need for development of hybrid systems and also offered a route towards integration of physicochemical and biological sensing systems for simultaneous monitoring of both environmental and biological elements.

abstract: The need for incorporating game engines into robotics tools becomes increasingly crucial as their graphics continue to become more photorealistic. This thesis presents a simulation framework, referred to as OpenUAV, that addresses cloud simulation and photorealism challenges in academic and research goals. In this work, OpenUAV is used to create a simulation of an autonomous underwater vehicle (AUV) closely following a moving autonomous surface vehicle (ASV) in an underwater coral reef environment. It incorporates the Unity3D game engine and the robotics software Gazebo to take advantage of Unity3D's perception and Gazebo's physics simulation. The software is developed as a containerized solution that is deployable on cloud and on-premise systems. This method of utilizing Gazebo's physics and Unity3D perception is evaluated for a team of marine vehicles (an AUV and an ASV) in a coral reef environment. A coordinated navigation and localization module is presented that allows the AUV to follow the path of the ASV. A fiducial marker underneath the ASV facilitates pose estimation of the AUV, and the pose estimates are filtered using the known dynamical system model of both vehicles for better localization. This thesis also investigates different fiducial markers and their detection rates in this Unity3D underwater environment. The limitations and capabilities of this Unity3D perception and Gazebo physics approach are examined. / Dissertation/Thesis / Masters Thesis Computer Science 2020

Gold nanoparticles, are one of the most widely investigated nanoparticles (NP) and are normally synthesized by the reduction of metal salts in citrate solution. The reason for studying this nanostructured material from a technological standpoint is mainly the anticipated application in different areas based on optical properties explained with plasmon resonance. The main work of this study was to develop different sensing systems using gold nanoparticles. Three techniques have been utilized, being lateral flow immunoassay (LFIA), surface plasmon resonance (SPR), and surface-enhanced Raman scattering (SERS). A one-step semi-quantitative LFIA strip test was developed using colloidal gold coated by a partially-purified polyclonal antibody (pAb) raised in sheep as a signal generator, and bovine serum albumin-Estriol-16-glucuronide (BSA-E3-16G) conjugates as the capture agent spotted onto a nitrocellulose membrane as the test line. In this system, gold nanoparticles were applied for visualising the response. The application of the strip sensor to urinary samples from pregnant woman proved successful. A quantitative evaluation of low levels of E3-16G in liquid media was developed based on SPR, which used the same pAb-nanogold conjugates employed for the LFIA analysis. The assay can be carried out directly on any urine samples without sample pretreatment. In this system, gold nanoparticles were utilized as high mass label to improve the sensitivity of the assay. A SERS probe was developed which comprised of Raman reporter molecules (RRM) and gold NPs. Results showed that the conducting polymer materials of 3’-[(E)-2-(4-R-phenyl)ethenyl]-2’2’:5’,2”-terthiophene (R-pe3T, where R is NO2 or NH2) showed significant enhancement. Moreover, high bio-activity groups included in the compounds make them potential candidates for the development of a SERS based sensing system.

Participatory Sensing Systems (PSS) are a type of Mobile Crowdsensing System where users voluntarily participate in contributing information. Task initiators create tasks, targeting specific data that needs to be gathered by the users’ device sensors. Such systems have been designed with different requirements, such as data trustworthiness, accountability, and incentives, in a secure and private way. However, it is complex to protect user privacy without affecting the performance of the rest of the system. For example, with task assignment, either the user authenticates anonymously, or discloses its sensors for an efficient allocation. If the user identity is hidden from the system, it could receive a task it cannot perform. This thesis aims to design an anonymous authentication model for PSS based on privacy-preserving attribute-based signatures. The proposed solution allows the Participatory Sensing System to enforce sensor requirements for efficient task allocation. In addition to the design, experiments measuring the performance of the operations are included in the thesis, to prove it is suitable for real-world scenarios. / Participatory Sensing Systems (PSS) är en typ av mobilt Crowdsensing-system där användare frivilligt deltar i att bidra med information. Aktivitetsinitiatorer skapar uppgifter, inriktade på specifik data som behöver samlas in av användarnas enhetssensorer. Sådana system har utformats med olika krav, såsom datatillförlitlighet, ansvarighet och incitament, på ett säkert och privat sätt. Det är dock komplicerat att skydda användarnas integritet utan att påverka prestandan för resten av systemet. Till exempel, med uppgiftstilldelning, antingen autentiserar användaren anonymt eller avslöjar sina sensorer för en effektiv tilldelning. Om användaridentiteten är dold från systemet kan den få en uppgift som den inte kan utföra. Denna avhandling syftar till att designa en anonym autentiseringsmodell för PSS baserad på integritetsbevarande attributbaserade signaturer. Den föreslagna lösningen gör det möjligt för Participatory Sensing System att upprätthålla sensorkrav för effektiv uppgiftsallokering. Utöver designen ingår experiment som mäter verksamhetens prestanda i avhandlingen, för att bevisa att den är lämplig för verkliga scenarier.