19,504 research outputs found

    Towards Autonomous Selective Harvesting: A Review of Robot Perception, Robot Design, Motion Planning and Control

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    This paper provides an overview of the current state-of-the-art in selective harvesting robots (SHRs) and their potential for addressing the challenges of global food production. SHRs have the potential to increase productivity, reduce labour costs, and minimise food waste by selectively harvesting only ripe fruits and vegetables. The paper discusses the main components of SHRs, including perception, grasping, cutting, motion planning, and control. It also highlights the challenges in developing SHR technologies, particularly in the areas of robot design, motion planning and control. The paper also discusses the potential benefits of integrating AI and soft robots and data-driven methods to enhance the performance and robustness of SHR systems. Finally, the paper identifies several open research questions in the field and highlights the need for further research and development efforts to advance SHR technologies to meet the challenges of global food production. Overall, this paper provides a starting point for researchers and practitioners interested in developing SHRs and highlights the need for more research in this field.Comment: Preprint: to be appeared in Journal of Field Robotic

    Corporate Social Responsibility: the institutionalization of ESG

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    Understanding the impact of Corporate Social Responsibility (CSR) on firm performance as it relates to industries reliant on technological innovation is a complex and perpetually evolving challenge. To thoroughly investigate this topic, this dissertation will adopt an economics-based structure to address three primary hypotheses. This structure allows for each hypothesis to essentially be a standalone empirical paper, unified by an overall analysis of the nature of impact that ESG has on firm performance. The first hypothesis explores the evolution of CSR to the modern quantified iteration of ESG has led to the institutionalization and standardization of the CSR concept. The second hypothesis fills gaps in existing literature testing the relationship between firm performance and ESG by finding that the relationship is significantly positive in long-term, strategic metrics (ROA and ROIC) and that there is no correlation in short-term metrics (ROE and ROS). Finally, the third hypothesis states that if a firm has a long-term strategic ESG plan, as proxied by the publication of CSR reports, then it is more resilience to damage from controversies. This is supported by the finding that pro-ESG firms consistently fared better than their counterparts in both financial and ESG performance, even in the event of a controversy. However, firms with consistent reporting are also held to a higher standard than their nonreporting peers, suggesting a higher risk and higher reward dynamic. These findings support the theory of good management, in that long-term strategic planning is both immediately economically beneficial and serves as a means of risk management and social impact mitigation. Overall, this contributes to the literature by fillings gaps in the nature of impact that ESG has on firm performance, particularly from a management perspective

    Countermeasures for the majority attack in blockchain distributed systems

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    La tecnología Blockchain es considerada como uno de los paradigmas informáticos más importantes posterior al Internet; en función a sus características únicas que la hacen ideal para registrar, verificar y administrar información de diferentes transacciones. A pesar de esto, Blockchain se enfrenta a diferentes problemas de seguridad, siendo el ataque del 51% o ataque mayoritario uno de los más importantes. Este consiste en que uno o más mineros tomen el control de al menos el 51% del Hash extraído o del cómputo en una red; de modo que un minero puede manipular y modificar arbitrariamente la información registrada en esta tecnología. Este trabajo se enfocó en diseñar e implementar estrategias de detección y mitigación de ataques mayoritarios (51% de ataque) en un sistema distribuido Blockchain, a partir de la caracterización del comportamiento de los mineros. Para lograr esto, se analizó y evaluó el Hash Rate / Share de los mineros de Bitcoin y Crypto Ethereum, seguido del diseño e implementación de un protocolo de consenso para controlar el poder de cómputo de los mineros. Posteriormente, se realizó la exploración y evaluación de modelos de Machine Learning para detectar software malicioso de tipo Cryptojacking.DoctoradoDoctor en Ingeniería de Sistemas y Computació

    Quantum dots based superluminescent diodes and photonic crystal surface emitting lasers

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    This thesis reports the design, fabrication, and electrical and optical characterisations of GaAs-based quantum dot (QD) photonic devices, specifically focusing on superluminescent diodes (SLDs) and photonic crystal surface-emitting lasers (PCSELs). The integration of QD active regions in these devices is advantageous due to their characteristics such as temperature insensitivity, feedback insensitivity, and ability to utilise the ground state (GS) and excited state (ES) of the dots. In an initial study concerning the fabrication of QD-SLDs, the influence of ridge waveguide etch depth on the electrical and optical properties of the devices are investigated. It is shown that the output power and modal gain from shallow etched ridge waveguide is higher than those of deep etched waveguides. Subsequently, the thermal performance of the devices is analysed. With increased temperature over 170 ºC, the spectral bandwidth is dramatically increased by thermally excited carrier transition in excited states of the dots. Following this, an investigation of a high dot density hybrid quantum well/ quantum dot (QW/QD) active structure for broadband, high-modal gain SLDs is presented. The influence of the number of QD layers on the modal gain of hybrid QW/QD structures is analysed. It is shown that higher number of dot layer provides higher modal gain value, however, there is lack of emission from QW due to the requirement of large number of carriers to saturate the QD. Additionally, a comparison is made between “unchirped QD” and “ chirped QD” of hybrid QW/QD structure in terms of modal gain and spectral bandwidth. It is showed that “chirped” of the QD can improve the “flatness” of the spectral bandwidth. Lastly, the use of self-assembled InAs QD as the active material in epitaxially regrown GaAs-based PCSELs is explored for the first time. Initially, it is shown that both GS and ES lasing can be achieved for QD-PCSELs by changing the grating period of the photonic crystal (PC). The careful design of these grating periods allows lasing from neighbouring devices at GS ( ~1230 nm) and ES (~1140 nm), 90 nm apart in wavelength. Following this, the effect of device area, PC etch depth, PC atom shape (circle or triangle or orientation) on lasing performance is presented. It is shown that lower threshold current density and higher slope efficiencies is achieved with increasing the device size. The deeper PC height device has higher output power due to more suitable height and minimal distance to active region. The triangular atom shape has slightly higher slope efficiency compared to triangular atom shape which is attributed to breaking in-plane symmetry and increase out-of-plane emission

    Measurement of telescope transmission using a Collimated Beam Projector

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    With the increasingly large number of type Ia supernova being detected by current-generation survey telescopes, and even more expected with the upcoming Rubin Observatory Legacy Survey of Space and Time, the precision of cosmological measurements will become limited by systematic uncertainties in flux calibration rather than statistical noise. One major source of systematic error in determining SNe Ia color evolution (needed for distance estimation) is uncertainty in telescope transmission, both within and between surveys. We introduce here the Collimated Beam Projector (CBP), which is meant to measure a telescope transmission with collimated light. The collimated beam more closely mimics a stellar wavefront as compared to flat-field based instruments, allowing for more precise handling of systematic errors such as those from ghosting and filter angle-of-incidence dependence. As a proof of concept, we present CBP measurements of the StarDICE prototype telescope, achieving a standard (1 sigma) uncertainty of 3 % on average over the full wavelength range measured with a single beam illumination

    Change of depressive symptoms during the course of electroconvulsive therapy (ECT) and predictive value of these symptoms for ECT outcome

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    Aim: Research examining change in symptoms of depression during treatment with electroconvulsive therapy (ECT) and proposing reliable predictors of ECT outcome is limited and previous studies have led to inconclusive results. This dissertation aims to explore the change of depressive symptomatology assessed with Montgomery-Åsberg Depression Rating Scale (MADRS) single items throughout the course of ECT and analyse the predictive value of these MADRS single items and their change throughout the course of ECT treatment regarding ECT outcome. Methods: This retrospective naturalistic study analysed MADRS data from 96 depressed psychiatric inpatients. MADRS data were routinely collected at three time points during the course of ECT treatment. ANOVAs for repeated measures were used to explore change of depressive symptomatology throughout the course of ECT. In order to analyse the predictive value of depressive symptomatology and its change regarding ECT treatment outcome logistic and linear regression models were applied. Results: Strongest reductions throughout the course of ECT treatment were found for MADRS items apparent sadness, reported sadness and inability to feel, assessing affective symptoms of depression. Lowest reductions were found for items assessing concentration difficulties and suicidal thoughts. MADRS single items were found to be potent predictors of ECT outcome, particularly the following items addressing affective symptomatology: apparent sadness, reported sadness, and inability to feel. Regression models that contained reported sadness indicated the most potent effects with as much as 80% correct prediction of ECT outcome. In order to determine a favorable MADRS cutoff value for ECT response, we conducted ROC analyses. Conclusions: Affective symptoms of depression decreased the most throughout the course of antidepressant ECT treatment. A favorable ECT outcome appears to be associated with more pronounced affective depressive symptomatology at baseline before treatment start and a stronger decline of affective symptomatology throughout the course of ECT. Additionally, precise cut-off values for clinical use after future validation were suggested. In search of reliable and easy-to-assess predictors of ECT outcome, depressive symptoms measured with MADRS single items could be regarded as a cost- and time-effective, valuable addition to clinical decision-making. In general, these findings illustrate the potential of a symptom-based approach, which might pose a useful expansion to the prevailing focus on depression sum-scores and generalized diagnostic categories in depression research and treatment.Ziel: Bislang liegen wenig belastbare Ergebnisse zur Veränderung distinkter depressiver Symptome durch die Behandlung mit EKT sowie zu zuverlässigen Prädiktoren einer erfolgreichen antidepressiven Behandlung mit EKT vor. Vorangegangene Studien haben zudem teils widersprüchliche Ergebnisse hervorgebracht. Diese Dissertation untersucht daher die Veränderung depressiver Symptome während der Behandlung mit EKT sowie die Vorhersagekraft initial bestehender depressiver Symptome und ihrer Veränderungen für eine erfolgreiche EKT-Behandlung. Einzelne depressive Symptome wurden dabei mittels Einzel-Items der Montgomery-Åsberg Depression Rating Scale (MADRS) erfasst. Methodik: In dieser naturalistischen retrospektiven Studie wurden MADRS Daten von 96 depressiven Patienten ausgewertet, die sich in stationärer psychiatrischer Behandlung befanden. Dabei wurden Daten von drei Messzeitpunkten im Verlauf der EKT-Behandlung analysiert. ANOVAs für Messwiederholungen wurden verwendet, um die Veränderung der depressiven Symptome im Verlauf der EKT-Behandlung zu untersuchen. Logistische und lineare Regressionsmodelle wurden angewandt, um die Vorhersagekraft distinkter depressiver Symptome und ihrer Veränderungen für eine erfolgreiche EKT-Behandlung zu explorieren. Ergebnisse: Die stärkste Symptomreduktion im Verlauf der EKT-Behandlung wurde für affektive Symptome gefunden; für die Items Sichtbare Traurigkeit, Berichtete Traurigkeit und Gefühllosigkeit. Die geringste Symptomreduktion wurde in Bezug auf Konzentrationsschwierigkeiten sowie Suizidgedanken gefunden. MADRS Einzel-Items waren wirksame Prädiktoren für das Ergebnis der EKT-Behandlung, insbesondere die o.g. affektiven Symptome. Die stärksten Effekte wurden dabei für Regressionsmodelle mit dem Item Berichtete Traurigkeit gefunden, mit bis zu 80% korrekter Vorhersage des Behandlungsergebnisses. Mittels ROC-Analysen konnten Schwellenwerte für die Vorhersage einer erfolgreichen EKT-Behandlung definiert werden. Schlussfolgerungen: Im Verlauf der antidepressiven Behandlung mit EKT reduzierte sich die affektive depressive Symptomatik am meisten. Eine stärker ausgeprägte affektive Symptomatik zu Behandlungsbeginn sowie eine stärkere Abnahme dieser affektiven Symptome im Behandlungsverlauf scheinen mit einem günstigeren Behandlungsergebnis einherzugehen. Dementsprechend könnten depressive Symptome erfasst anhand von MADRS Einzel-Items einfache, zuverlässige sowie zeit- und kostensparende Prädiktoren für erfolgreiche EKTBehandlungen darstellen und somit einen wertvollen Beitrag zur klinischen Entscheidungsfindung leisten. Diese Befunde verdeutlichen zudem den zusätzlichen Nutzen symptombasierter Depressionsforschung und –behandlung als Ergänzung zur weiterhin vorherrschenden Fokussierung auf Summenscores und übergeordnete Diagnosekriterien

    Anuário científico da Escola Superior de Tecnologia da Saúde de Lisboa - 2021

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    É com grande prazer que apresentamos a mais recente edição (a 11.ª) do Anuário Científico da Escola Superior de Tecnologia da Saúde de Lisboa. Como instituição de ensino superior, temos o compromisso de promover e incentivar a pesquisa científica em todas as áreas do conhecimento que contemplam a nossa missão. Esta publicação tem como objetivo divulgar toda a produção científica desenvolvida pelos Professores, Investigadores, Estudantes e Pessoal não Docente da ESTeSL durante 2021. Este Anuário é, assim, o reflexo do trabalho árduo e dedicado da nossa comunidade, que se empenhou na produção de conteúdo científico de elevada qualidade e partilhada com a Sociedade na forma de livros, capítulos de livros, artigos publicados em revistas nacionais e internacionais, resumos de comunicações orais e pósteres, bem como resultado dos trabalhos de 1º e 2º ciclo. Com isto, o conteúdo desta publicação abrange uma ampla variedade de tópicos, desde temas mais fundamentais até estudos de aplicação prática em contextos específicos de Saúde, refletindo desta forma a pluralidade e diversidade de áreas que definem, e tornam única, a ESTeSL. Acreditamos que a investigação e pesquisa científica é um eixo fundamental para o desenvolvimento da sociedade e é por isso que incentivamos os nossos estudantes a envolverem-se em atividades de pesquisa e prática baseada na evidência desde o início dos seus estudos na ESTeSL. Esta publicação é um exemplo do sucesso desses esforços, sendo a maior de sempre, o que faz com que estejamos muito orgulhosos em partilhar os resultados e descobertas dos nossos investigadores com a comunidade científica e o público em geral. Esperamos que este Anuário inspire e motive outros estudantes, profissionais de saúde, professores e outros colaboradores a continuarem a explorar novas ideias e contribuir para o avanço da ciência e da tecnologia no corpo de conhecimento próprio das áreas que compõe a ESTeSL. Agradecemos a todos os envolvidos na produção deste anuário e desejamos uma leitura inspiradora e agradável.info:eu-repo/semantics/publishedVersio

    Evaluating environmental effects in construction and demolition waste recycling plant with the Iranian Leopold Matrix method

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    BACKGROUND AND OBJECTIVES: Recycling and reusing construction and demolition debris is a productive step toward solving this problem. Still, the recycling process also leaves industrial effluents, which is evident in producing recycled sand. The present research has investigated the environmental effects of recycling construction debris at sand recycling plants. Considering the negative impacts of sand washing mud produced at the plant in the Aab'Ali Landfill of Tehran in Iran, the material's physicochemical characteristics and environmental impact have also been investigated to regulate practices.                        METHODS: The Environmental Impact Assessment has been carried out in physicochemical, biological, socio-cultural, and economic-technical areas. Due to the large dispersion of the studied soil and the composition diversity in each sampling, 30 samples of the sand washing mud and the material mixed with the surrounding soil have been collected. The exploitation phase during the factory construction plan's implementation stage was considered the current research's main phase. Hence, 13 micro activities and 23 environmental parameters were identified, and the results were analyzed in the Environmental Impact Assessment Plus Software using the Iranian Leopold Matrix method and discussed based on the results of the experiments.FINDINGS: According to the results of the matrix calculation, the three micro-activities included washing the sand through a sand-washing machine, fine sand washing through the EvoWash machine with a score of -3.6, converting concrete pieces and large boulders into smaller pieces by jackhammers, transferring to the jaw crusher machine with a score of -2.8, and transferring the remaining sand washing mud produced by the EvoWash machine to the storage pond with a score of -2.7 had the most negative effects. The three micro-activities of waste processing for green space irrigation (+2.2), selling products (+0.9), and hiring employees with a score of +0.5 have the most positive effects on the environment. As ranking smaller than -31 forming 50% of the total average of rows and columns, the activity of the plant and the sand extraction process in this landfill is approved by providing modification alternatives.CONCLUSION: Considering the positive impact on the economy, increasing green spaces in the region, job creation, and also reducing the amount of increasing debris accumulated in the landfill is evaluated positively and can be done considering the reforms; including the prevention of releasing remnant sand washing mud freely and recycling it instead. Reusing the sand washing mud requires improving the water purification systems used in the EvoWash machine
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