5,229 research outputs found

    Beam scanning by liquid-crystal biasing in a modified SIW structure

    Get PDF
    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    Multimodal spatio-temporal deep learning framework for 3D object detection in instrumented vehicles

    Get PDF
    This thesis presents the utilization of multiple modalities, such as image and lidar, to incorporate spatio-temporal information from sequence data into deep learning architectures for 3Dobject detection in instrumented vehicles. The race to autonomy in instrumented vehicles or self-driving cars has stimulated significant research in developing autonomous driver assistance systems (ADAS) technologies related explicitly to perception systems. Object detection plays a crucial role in perception systems by providing spatial information to its subsequent modules; hence, accurate detection is a significant task supporting autonomous driving. The advent of deep learning in computer vision applications and the availability of multiple sensing modalities such as 360° imaging, lidar, and radar have led to state-of-the-art 2D and 3Dobject detection architectures. Most current state-of-the-art 3D object detection frameworks consider single-frame reference. However, these methods do not utilize temporal information associated with the objects or scenes from the sequence data. Thus, the present research hypothesizes that multimodal temporal information can contribute to bridging the gap between 2D and 3D metric space by improving the accuracy of deep learning frameworks for 3D object estimations. The thesis presents understanding multimodal data representations and selecting hyper-parameters using public datasets such as KITTI and nuScenes with Frustum-ConvNet as a baseline architecture. Secondly, an attention mechanism was employed along with convolutional-LSTM to extract spatial-temporal information from sequence data to improve 3D estimations and to aid the architecture in focusing on salient lidar point cloud features. Finally, various fusion strategies are applied to fuse the modalities and temporal information into the architecture to assess its efficacy on performance and computational complexity. Overall, this thesis has established the importance and utility of multimodal systems for refined 3D object detection and proposed a complex pipeline incorporating spatial, temporal and attention mechanisms to improve specific, and general class accuracy demonstrated on key autonomous driving data sets

    The Entrenched Political Limitations of Australian Refugee Policy: A Case Study of the Australian Labor Party (2007-2013)

    Full text link
    This thesis deconstructs Australia’s asylum and refugee policy trajectory under the Labor government between 2007 and 2013. For a short time after the 2007 election, in accordance with its promise to abolish the LNP’s Pacific Solution, Labor began to unwind certain policy structures of externalisation and deterrence that had been in place since the introduction of mandatory detention in 1992. By 2013 however, the ALP had declared that asylum seekers arriving by boat had no prospect of resettlement in Australia. This thesis analyses the political strategy of the ALP in rhetoric, policy choices and policy justifications to derive lessons from Labor’s mitigated challenge to the deterrence/externalisation paradigm. Critical Discourse Analysis is used to examine the political strategies of lead actors, particularly the ALP and the LNP, and to reconcile these strategies with policy outcomes such as irregular arrivals, detention figures, deaths at sea and compliance with obligations under international law. A central argument of this thesis is that Labor’s attempt to sustainably depart from the dominant externalisation paradigm was impaired, not by a lack of commitment to its stated program of reform, but rather by entrenched political limitations of the Australian context. These limitations include the LNP’s rigid partisanship and lack of policy compromise, the deep-rooted nature of mandatory detention, and the Australian public’s historical and continued support for controlled migration. A precise and detailed analysis of the impact of these limitations on Labor’s proposed reform fills a gap in academic knowledge about the political influences on policy action in Australian asylum and refugee policy. I contend that these limitations must be effectively engaged with in any attempt to reform the Australian asylum and refugee policy space

    2023-2024 Boise State University Undergraduate Catalog

    Get PDF
    This catalog is primarily for and directed at students. However, it serves many audiences, such as high school counselors, academic advisors, and the public. In this catalog you will find an overview of Boise State University and information on admission, registration, grades, tuition and fees, financial aid, housing, student services, and other important policies and procedures. However, most of this catalog is devoted to describing the various programs and courses offered at Boise State

    Cyberbullying in educational context

    Get PDF
    Kustenmacher and Seiwert (2004) explain a man’s inclination to resort to technology in his interaction with the environment and society. Thus, the solution to the negative consequences of Cyberbullying in a technologically dominated society is represented by technology as part of the technological paradox (Tugui, 2009), in which man has a dual role, both slave and master, in the interaction with it. In this respect, it is noted that, notably after 2010, there have been many attempts to involve artificial intelligence (AI) to recognize, identify, limit or avoid the manifestation of aggressive behaviours of the CBB type. For an overview of the use of artificial intelligence in solving various problems related to CBB, we extracted works from the Scopus database that respond to the criterion of the existence of the words “cyberbullying” and “artificial intelligence” in the Title, Keywords and Abstract. These articles were the subject of the content analysis of the title and, subsequently, only those that are identified as a solution in the process of recognizing, identifying, limiting or avoiding the manifestation of CBB were kept in the following Table where we have these data synthesized and organized by years

    Modelling, Monitoring, Control and Optimization for Complex Industrial Processes

    Get PDF
    This reprint includes 22 research papers and an editorial, collected from the Special Issue "Modelling, Monitoring, Control and Optimization for Complex Industrial Processes", highlighting recent research advances and emerging research directions in complex industrial processes. This reprint aims to promote the research field and benefit the readers from both academic communities and industrial sectors

    Identification of Micro- and Submicron (Nano) Plastics in Water Sources and the Impact of COVID-19 on Plastic Pollution

    Get PDF
    One of the most significant environmental issues that our society may deal with this century could be plastics. The world's water bodies, as well as land and air, are becoming more and more contaminated by plastic due to the ongoing and expanding manufacturing of these synthetic materials, as well as the lack of an effective strategy for managing plastic waste. The fact that plastics break down into smaller particles (micro and nanoplastics) by action of environmental physical and chemical reactions, and do not degrade biologically in a reasonable time, is a cause of concern as plastics are believed to cause harm in animals, plants and humans.To identify the types of plastics prevalent in aquatic habitats, a number of procedures have been developed, from sampling to identification. After a water body has been sampled using nets, pumps, or other tools, depending on the type of sample taken, it is usually necessary to treat the samples for separation and purification. The next stage is to employ analytical techniques to identify the synthetic contaminants. The most common approaches are microscopy, spectroscopy, and thermal analysis. This thesis gives an overview of where in the environment microplastics (MPs) and nanoplastics (NPs) can be found and summarizes the most important technologies applied to analyse the importance of plastics as a contaminant in water bodies. The development of standardised analytical procedures is still necessary as most of them are not suitable for the identification of particles below 50 μm due to resolution limitations. The preparation and analysis of samples are usually time-consuming factors that shall be considered. Particularly for MP and NP analysis in aqueous samples, thermal analysis methods based on sample degradation are generally not considered to be the most effective approach. Nevertheless, Pyrolysis - Gas Chromatography Time-of-Flight Mass Spectrometry (Py-GCToFMS) is used in this thesis to propose a novel approach as due to its unique detection abilities, and with a novel filtration methodology for collection, it enables the identification of tiny particle sizes (>0.1 μm) in water samples.PTFE membranes were selected to filter the liquid samples using a glass filtration system. This way, the synthetic particles will be deposited on the membranes and will allow the study and analysis of the precipitated material. PTFE is a readily available, reasonably priced, and adaptable product that makes sample preparation quick and simple.The three plastics under study—polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC)—can be identified from complex samples at trace levels thanks to the employment of these widely used membranes and the identification of various and specific (marker) ions. The technique was examined against a range of standards samples that contained predetermined concentrations of MPs and NPs. Detection levels were then determined for PVC and PS and were found to be below <50 μg/ L, with repeatable data showing good precision (RSD <20 %). The examination of a complex matrix sample taken from a nearby river contributed to further validate this innovative methodology; the results indicated the existence of PS with a semi-quantifiable result of 250.23 g/L. Because of this, PY-GCToFMS appears to be a method that is appropriate for the task of identifying MPs and NPs from complex mixtures.This thesis also focuses on the environmental challenge that disposable plastic face masks (DPFMs) pose, which has been made significantly worse due to the COVID-19 pandemic. By the time this thesis was written, the production of disposable plastic facemasks had reached to approximately 200 million a day, in a global effort to tackle the spread of the new SARS-CoV-2 virus. This thesis investigates the emissions of pollutants from several different DPFM brands (medical and non-medical) that were submerged in water to replicate the conditions in the environment after these DPFMs have been discarded. The DPFM leachates were filtered using inorganic membranes type and characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Light/Optical Microscopy (LM/OM), Inductively coupled plasma mass spectrometry (ICP-MS) and Liquid chromatography–mass spectrometry (LC-MS). Micro and nano scale polymeric fibres, particles, siliceous fragments and leachable inorganic and organic chemicals were observed from all of the tested DPFMs. For non-medical DPFMs, traces of concerning heavy metals were detected in association with silicon containing fragments (i.e. lead up to 6.79 μg/L). ICP-MS also confirmed the presence of other leachable metals like cadmium (up to 1.92 μg/L), antimony (up to 3.93 μg/L) and copper (up to 4.17 μg/L). LC-MS analysis identified organic species related to plastic additives; polyamide-66 monomer and oligomers (nylon-66 synthesis), surfactant molecules, and dye-like molecules were all tentatively identified in the leachate. The question of whether DPFMs are safe to use daily and what implications may be anticipated after their disposal into the environment is brought up by the toxicity of some of the chemicals discovered.The previous approach is expanded to medical DPFMs with the utilisation of Field Emission Gun Scanning Electron Microscope (FEG-SEM) in order to get high resolution images of the micro and nanoparticles deposited on the membranes. It is also incorporated the use of 0.02 μm pore size inorganic membranes to better identify the nanoparticles released.Separated aqueous samples were also obtained by submerging medical DPFMs for 24 hours to be analysed using ICP-MS and LC-MS.Both particles and fibres in the micro and nano scale were found in all 6 DPFMs brands of this study. EDS analysis revealed the presence of particles containing different heavy metals like lead, mercury, and arsenic among others. ICP-MS analysis results confirmed traces of heavy metals (antimony up to 2.41 μg/L and copper up to 4.68 μg/L). LC-MS analysis results identified organic species related to plastic additives and contaminants; polyamide-66 monomer and oligomers (nylon-66 synthesis), surfactant molecules, and polyethylene glycol were all tentatively identified in the leachate. The toxicity of some of the chemicals found raises the question of whether DPFMs are safe to be used on a daily basis and what consequences are to be expected after their disposal into the environment
    corecore