A Stochastic Hybrid Framework for Driver Behavior Modeling Based on Hierarchical Dirichlet Process

Scalability is one of the major issues for real-world Vehicle-to-Vehicle network realization. To tackle this challenge, a stochastic hybrid modeling framework based on a non-parametric Bayesian inference method, i.e., hierarchical Dirichlet process (HDP), is investigated in this paper. This framework is able to jointly model driver/vehicle behavior through forecasting the vehicle dynamical time-series. This modeling framework could be merged with the notion of model-based information networking, which is recently proposed in the vehicular literature, to overcome the scalability challenges in dense vehicular networks via broadcasting the behavioral models instead of raw information dissemination. This modeling approach has been applied on several scenarios from the realistic Safety Pilot Model Deployment (SPMD) driving data set and the results show a higher performance of this model in comparison with the zero-hold method as the baseline.Comment: This is the accepted version of the paper in 2018 IEEE 88th Vehicular Technology Conference (VTC2018-Fall) (references added, title and abstract modified

Insomnia : the affordance of hybrid media in visualising a sleep disorder

The integration of visual and numerical abstraction in contemporary audio-visual communication has become increasingly prevalent. This increase reflects the evolution of computational machines from simple data processors. Computation and interface have augmented our senses and converged algorithmic logic with cultural techniques to form hybrid channels of communication. These channels are fluid and mutable, allowing creatives to explore and disseminate knowledge through iterative media practice. Insomnia is an auto-ethnographic case study that examines the affordance of merging Brain-Computer Interfaces (BCIs) and node- based programming software (TouchDesigner), as a hybrid media system (McMullan, 2020). As a system, Insomnia compiles my archived brain activity data and processes it through a custom designed generative visualisation interface. Documenting and ‘processing’ a sleep disorder is filtered through key concepts of media archaeology, cultural techniques, and practice-led research allowing Insomnia to inform discussion of the affordance of hybrid media. Insomnia is presented as a virtual exhibition with a supporting exegesis. The methodology and outcomes of the project form a framework that bridges science communication and creative practice and points to continued development for interactive installation design

3D PRINTED FOOTWEAR DESIGN

This project is focused on developing a range of design concepts for printable footwear. The idea is to build a consumer based system, which reduces labor for manufacturing and provides ease of access to new products for consumers. Experts predict that everyone will have a 3D printer at home in the near future and people will be able to design and make objects on their own (Dale Nicholls 2014). Currently the 3D printing technology is not developed enough for non-designer use. By developing a range of stylish footwear design concepts, the production process would speed up and the costs of production would be reduced. This idea will allow everyone to use prepared designs and print usable products on their personal 3D printers. This footwear will be designed in a way that lets a regular 3D printer make it without fail. In addition, the final CAD files of products will be accessible to 3D printer owners

Fabrication of thin film solar cell materials by APCVD

Thin film solar cells are currently being implemented commercially as they reduce the amount of semiconductor material required for each cell when compared to silicon wafers, thereby lowering the cost of production. Currently two direct band gap chalcogenide thin-film technologies, CdTe and CuInGa(S,Se)2 (CIGS), yield the highest reported power conversion efficiencies of 16.5% and 20.3%, respectively. In addition, Cu2ZnSnS4 (CZTS) is one of the most promising chalcogenide thin film photovoltaic absorber materials; with an optimal band gap of about 1.5 eV. More importantly, CZTS consists of abundant and non-toxic elements, so research on CZTS thin-film solar cells has been increasing significantly in recent years. Moreover, Sb2S3 based chalcogenide thin films have been proposed for use in photovoltaic applications. The preparation of chalcogenide thin films solar cells commonly use physical vapour deposition methods including thermal/e-beam evaporation, sputtering, and pulsed laser deposition, electrochemical deposition, spray pyrolysis, solution-based synthesis, followed by the sulfurization or selenization annealing process. In this paper, we report a non-vacuum process, using atmospheric pressure chemical vapour deposition (APCVD), to fabricate chalcogenide thin film solar cell materials as well as transparent conductive oxide (TCO) thin films. The optical, electrical, and structural properties of these materials were characterized by UV-VIS-NIR, four-point probes, SEM, EDX, XRD, Micro-Raman

The Effect of Non-Local Electrical Conductivity on Near-Field Radiative Heat Transfer Between Graphene Sheets

Every object above zero kelvin emits electromagnetic radiation with the dominant wavelength determined using the Wien’s law (10 microns at room temperature). These waves can transfer energy and hence are the foundation of radiative heat transfer (RHT). RHT consists of two regimes: far-field and near-field. If the distance between the heat exchanging media is more than the dominant wavelength, the regime is far-field and is limited to the ideal Planck’s blackbody, and only propagating waves contribute to heat transfer. On the other hand, when the distance is less than the dominant wavelength, the regime is called the near-field. In near-field radiative heat transfer (NFRHT), the contribution of evanescent waves becomes more significant than the propagating ones, and this causes a spike in the spectral RHT that exceeds Planck’s blackbody limit by several orders of magnitude. If the thermal emitter supports surface modes, NFRHT can become monochromatic. These surface modes can be surface phonon polaritons (SPhP) and surface plasmon polaritons (SPP). Materials such as silicon carbide support SPhP and graphene is an example of a material that support SPPs. These surface modes cause the quasi-monochromatic behavior that can be exploited for applications such as thermophotovoltaic devices and thermal rectifiers. Graphene is one of the few materials that support surface modes in the infrared where these modes can be thermally excited. Another characteristic of graphene SPPs is their tunability using gate voltage or chemical doping which has transformed graphene into a revolutionary material for NFRHT applications in mid-to far-infrared regions. Graphene has been studied both theoretically and experimentally. However, in most NFRHT studies, graphene has been investigated theoretically for its application in NFRHT. NFRHT for graphene is calculated using its electrical conductivity. The studies in NFRHT have utilized a local method for graphene’s electrical conductivity called the Kubo formula. However, graphene is a non-local material that has non-local conductivity and dielectric response, hence it is not clear whether a local model such as the Kubo formula can capture the non-local behavior of graphene. In this thesis, a non-local model called the Lindhard formula is used to calculate graphene’s conductivity, and the radiative conductance between two graphene sheets. The Lindhard predictions are compared with the results obtained from the Kubo formula. It is found that at low chemical potential both methods agree, while by increasing the chemical potential of graphene, the Kubo formula overestimates the radiative conductance between two graphene sheets by several orders of magnitude. Increasing the gap size and reducing temperature would increase the difference. It is concluded that the observed differences are due to the simplification involved when deriving the Kubo formula, and therefore it is recommended to use the Lindhard formula in NFRHT studies