868 research outputs found

    Improving Deep Learning-based Defect Detection on Window Frames with Image Processing Strategies

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    Detecting subtle defects in window frames, including dents and scratches, is vital for upholding product integrity and sustaining a positive brand perception. Conventional machine vision systems often struggle to identify these defects in challenging environments like construction sites. In contrast, modern vision systems leveraging machine and deep learning (DL) are emerging as potent tools, particularly for cosmetic inspections. However, the promise of DL is yet to be fully realized. A few manufacturers have established a clear strategy for AI integration in quality inspection, hindered mainly by issues like scarce clean datasets and environmental changes that compromise model accuracy. Addressing these challenges, our study presents an innovative approach that amplifies defect detection in DL models, even with constrained data resources. The paper proposes a new defect detection pipeline called InspectNet (IPT-enhanced UNET) that includes the best combination of image enhancement and augmentation techniques for pre-processing the dataset and a Unet model tuned for window frame defect detection and segmentation. Experiments were carried out using a Spot Robot doing window frame inspections . 16 variations of the dataset were constructed using different image augmentation settings. Results of the experiments revealed that, on average, across all proposed evaluation measures, Unet outperformed all other algorithms when IPT-enhanced augmentations were applied. In particular, when using the best dataset, the average Intersection over Union (IoU) values achieved were IPT-enhanced Unet, reaching 0.91 of mIoU

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

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    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

    Towards an integrated vulnerability-based approach for evaluating, managing and mitigating earthquake risk in urban areas

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    Tese de doutoramento em Civil EngineeringSismos de grande intensidade, como aqueles que ocorreram na Turquía-Síria (2023) ou México (2017) deviam chamar a atenção para o projeto e implementação de ações proativas que conduzam à identificação de bens vulneráveis. A presente tese propõe um fluxo de trabalho relativamente simples para efetuar avaliações da vulnerabilidade sísmica à escala urbana mediante ferramentas digitais. Um modelo de vulnerabilidade baseado em parâmetros é adotado devido à afinidade que possui com o Catálogo Nacional de Monumentos Históricos mexicano. Uma primeira implementação do método (a grande escala) foi efetuada na cidade histórica de Atlixco (Puebla, México), demonstrando a sua aplicabilidade e algumas limitações, o que permitiu o desenvolvimento de uma estratégia para quantificar e considerar as incertezas epistémicas encontradas nos processos de aquisição de dados. Devido ao volume de dados tratado, foi preciso desenvolver meios robustos para obter, armazenar e gerir informações. O uso de Sistemas de Informação Geográfica, com programas à medida baseados em linguagem Python e a distribuição de ficheiros na ”nuvem”, facilitou a criação de bases de dados de escala urbana para facilitar a aquisição de dados em campo, os cálculos de vulnerabilidade e dano e, finalmente, a representação dos resultados. Este desenvolvimento foi a base para um segundo conjunto de trabalhos em municípios do estado de Morelos (México). A caracterização da vulnerabilidade sísmica de mais de 160 construções permitiu a avaliação da representatividade do método paramétrico pela comparação entre os níveis de dano teórico e os danos observados depois do terramoto de Puebla-Morelos (2017). Esta comparação foi a base para efetuar processos de calibração e ajuste assistidos por algoritmos de aprendizagem de máquina (Machine Learning), fornecendo bases para o desenvolvimento de modelos de vulnerabilidade à medida (mediante o uso de Inteligência Artificial), apoiados nas evidências de eventos sísmicos prévios.Strong seismic events like the ones of Türkiye-Syria (2023) or Mexico (2017) should guide our attention to the design and implementation of proactive actions aimed to identify vulnerable assets. This work is aimed to propose a suitable and easy-to-implement workflow for performing large-scale seismic vulnerability assessments in historic environments by means of digital tools. A vulnerability-oriented model based on parameters is adopted given its affinity with the Mexican Catalogue of Historical Monuments. A first large-scale implementation of this method in the historical city of Atlixco (Puebla, Mexico) demonstrated its suitability and some limitations, which lead to develop a strategy for quantifying and involving the epistemic uncertainties found during the data acquisition process. Given the volume of data that these analyses involve, it was necessary to develop robust data acquisition, storing and management strategies. The use of Geographical Information System environments together with customised Python-based programs and cloud-based distribution permitted to assemble urban databases for facilitating field data acquisition, performing vulnerability and damage calculations, and representing outcomes. This development was the base for performing a second large-scale assessment in selected municipalities of the state of Morelos (Mexico). The characterisation of the seismic vulnerability of more than 160 buildings permitted to assess the representativeness of the parametric vulnerability approach by comparing the theoretical damage estimations against the damages observed after the Puebla-Morelos 2017 Earthquakes. Such comparison is the base for performing a Machine Learning assisted process of calibration and adjustment, representing a feasible strategy for calibrating these vulnerability models by using Machine-Learning algorithms and the empirical evidence of damage in post-seismic scenarios.This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), reference UIDB/04029/2020. This research had financial support provided by the Portuguese Foundation of Science and Technology (FCT) through the Analysis and Mitigation of Risks in Infrastructures (InfraRisk) program under the PhD grant PD/BD/150385/2019

    Assessment of Physical Activity in Adults with Progressive Muscle Disease

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    Introduction: Insufficient physical activity is a major threat to global health. Physical activity benefits peoples’ physical and mental health. The general population, including people living with disabilities and muscle wasting conditions, are recommended to avoid excessive sedentary time and engage in daily activity. Adults with progressive muscle disease experience barriers to physical activity participation, including muscle weakness, fatigue, physical deconditioning, impairment, activity limitations and participation restrictions (including societal and environmental factors), and fear of symptom exacerbation. More research is required to understand the inter-relationship between health and physical activity for adults with progressive muscle disease, particularly non-ambulant people who are under-represented in the existing research literature. Accurate measurement of FITT (frequency, intensity, time, and type of physical activity) is vital for high-quality physical activity assessment. The aim of this thesis was to assess the physical activity of ambulant and non-ambulant adults with progressive muscle disease.Systematic review findings identified various measures used to assess physical activity in adults with muscular dystrophy, including accelerometers, direct observation, heart rate monitors, calorimetry, positioning systems, activity diaries, single scales, interviews and questionnaires. None of the measures identified in the systematic review had well established measurement properties for adults with muscular dystrophy.Patient and public involvement interviews highlighted the importance of inclusive, remote, and technology-facilitated research design, the potential intrusion of direct observations of physical activity, the familiarity of questionnaires for data collection, and practical considerations to ensure wearing an activity monitor was not too burdensome.A feasibility study using multiple methods in 20 ambulant and non-ambulant adults with progressive muscle disease revealed satisfactory acceptability, interpretability, and usability of Fitbit and activity questionnaires, in both paper and electronic formats. During supervised activity tasks, Fitbit was found to have satisfactory criterion validity, reliability, and responsiveness and measurement properties were strengthened using multisensory measurement.An observational, longitudinal study that included 111 ambulant and non-ambulant adults with progressive muscle disease showed that:Activity monitoring had satisfactory validity, reliability and responsiveness using Fitbit, but there was considerable measurement error between Fitbit and the research grade GENEActiv accelerometer. Fitbit thresholds and multiple metrics (including accelerometer and heart rate data extrapolations of FITT) were appropriate for physical activity assessment in ambulant and non-ambulant adults with progressive muscle disease.Activity self-report had unsatisfactory concurrent validity, test-retest reliability, and responsiveness with substantial activity overestimation using the modified International Physical Activity Questionnaire. However, self-report properties were improved when used concurrently with Fitbit.Observed physical activity in adults with progressive muscle disease was generally low with excessive daily sedentary time. Activity frequencies, intensities and durations were lower, and activity types were more domestic, for wheelchair users and during the COVID-19 lockdown. Lower physical activity was significantly associated with greater functional impairment, less cardiorespiratory fitness, worse metabolic health, and lower quality of life. Activity optimisation thresholds and minimal clinically important differences were established.Discussion: The implications of this thesis include guidance for selection of appropriate physical activity measures by clinicians and researchers working with adults with progressive muscle disease. Fitbit is suitable in clinical practice and research for interactive, weekly remote activity monitoring or to support activity self-management and may represent an appropriate compromise between potential underestimation by accelerometry alone, and overestimation by self-report alone. A draft conceptual framework for physical activity measurement was also proposed. It includes frequency, intensity, time, and type of physical activity, and incorporates wider aspects of the physical activity construct, including somatic factors (relating to progressive muscle disease and underlying fitness) and contextual factors (relating to personal, social, and environmental situations). Future research will build on the knowledge gained in this thesis, furthering understanding of the inter-relationships between physical activity, health and wider contexts. Implementation will include testing a remote physical activity optimisation intervention that is inclusive of ambulant and non-ambulant participants, featuring Fitbit self-monitoring with a focus on optimisation of daily activity frequency and regularly interrupting sedentary time.</div

    Food - Media - Senses: Interdisciplinary Approaches

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    Food is more than just nutrition. Its preparation, presentation and consumption is a multifold communicative practice which includes the meal's design and its whole field of experience. How is food represented in cookbooks, product packaging or in paintings? How is dining semantically charged? How is the sensuality of eating treated in different cultural contexts? In order to acknowledge the material and media-related aspects of eating as a cultural praxis, experts from media studies, art history, literary studies, philosophy, experimental psychology, anthropology, food studies, cultural studies and design studies share their specific approaches

    A risk management model for commercial property development and investment in Ghana

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    Commercial property development and investment provide many benefits to individuals and governments around the globe; these include the generation of income for investors, employment, tax revenues, and contributions to a country‘s GDP. Yet commercial property development and investment projects involve construction, economic and management risks. A lack of effective risk assessment and management tools may lead to developers and investors incurring losses. To curtail such losses, this study sought to create a credible management model that can be used to assess and manage risks in Ghana‘s commercial property development and investment industry. An extensive literature review was done, covering all 12 identified study constructs: real estate trends and cycle, construction project management, outside advice/mentorship, spatial development, strategic factors, business management skills, PMBOK, PESTEL analysis, general management skills, governance structures, financial feasibility, professional feasibility, and risk management. Each construct was defined and operationalised. A positivistic philosophical approach was used, and quantitative approach was used to solicit data from the main respondents through the distribution of questionnaires to the target population sample. CB-SEM and SPSS version 24 were used to analyse data, SEM to test the positive relationships hypothesised between the identified variables and SPSS to analyse the demographic data. The major findings are that there is a lack of financial and professional feasibility analysis among respondents along the following factors: the PMBOK, real estate trends and cycles, general management, business management, strategic factors, spatial development, and PESTEL analysis. It was found that these factors have positive and favourable influences on CPDI projects. The study recommends that developers and investors do financial and professional feasibility studies before they embark on projects. This could improve project viability in commercial property development and investment. The study has contributed to the body of knowledge in CPDI sector by developing a new risk assessment/risk management model.Thesis (PhD) -- Faculty of Engineering Built Environment and Technology, School of the built Environment, 202

    Designing a New Tactile Display Technology and its Disability Interactions

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    People with visual impairments have a strong desire for a refreshable tactile interface that can provide immediate access to full page of Braille and tactile graphics. Regrettably, existing devices come at a considerable expense and remain out of reach for many. The exorbitant costs associated with current tactile displays stem from their intricate design and the multitude of components needed for their construction. This underscores the pressing need for technological innovation that can enhance tactile displays, making them more accessible and available to individuals with visual impairments. This research thesis delves into the development of a novel tactile display technology known as Tacilia. This technology's necessity and prerequisites are informed by in-depth qualitative engagements with students who have visual impairments, alongside a systematic analysis of the prevailing architectures underpinning existing tactile display technologies. The evolution of Tacilia unfolds through iterative processes encompassing conceptualisation, prototyping, and evaluation. With Tacilia, three distinct products and interactive experiences are explored, empowering individuals to manually draw tactile graphics, generate digitally designed media through printing, and display these creations on a dynamic pin array display. This innovation underscores Tacilia's capability to streamline the creation of refreshable tactile displays, rendering them more fitting, usable, and economically viable for people with visual impairments
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