52 research outputs found

    Algorithmic aversion in artificial intelligence co-leadership and the impact of metaphors and comparisons

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    The importance of Artificial Intelligence (AI) has been increasing at a fast pace. Besides transforming our lives, these technologies are crucial to improving business operations by conducting tasks faster, better and with lower costs, and by helping in the decision­making process that is an intellectually demanding task. However, despite the advantages AI can offer, people still disbelieve the ability of algorithms, often prefer to decide for themselves and refuse to rely on algorithms after seeing them err. This phenomenon is called algorithm aversion and goes against the best interest of companies that need to gain competitive advantage in a very competitive market. In this way, this dissertation intends to study the potential use of metaphors and comparisons as strategies to reduce algorithm aversion. For this to be done, an experimental study with three experimental groups was conducted. The effect of a language­based metaphor, a visual metaphor and an explicit comparison between human and artificial neurons was studied by relying on a specific type of AI called Artificial Neural Network (ANN) to see if people would prefer this technology that seems to function in a similar way to humans, over a general AI in a leadership position. The results of the study did not corroborate the hypothesis that the metaphors were going to reduce algorithm aversion, as the only difference found in the leadership acceptance was between the general AI group and the human one in which the new leader was a normal person.A importância da Inteligência Artificial (IA) tem aumentado a um ritmo rápido. Além de transformar as nossas vidas, estas tecnologias são cruciais para melhorar operações de empresas, realizando tarefas de modo mais rápido, melhor, com menos custos, e auxiliando a tomada de decisão que é uma tarefa intelectualmente exigente. No entanto, apesar das vantagens que a IA pode oferecer, as pessoas ainda não acreditam na capacidade dos algoritmos, muitas vezes preferem decidir por si mesmas e recusam­se a confiar nos algoritmos depois de os verem errar. Este fenómeno é chamado de aversão ao algoritmo e vai contra o melhor interesse das empresas que precisam de ganhar vantagem competitiva num mercado muito competitivo. Assim, esta dissertação pretende estudar o potencial uso de metáforas e comparações como estratégias para reduzir a aversão a algoritmos. Para isso, foi realizado um estudo experimental com três grupos experimentais. O efeito de uma metáfora linguística, uma metáfora visual e uma comparação explícita entre neurónios humanos e artificiais foi estudado através de um tipo específico de IA chamada Rede Neural Artificial (RNA) para ver se as pessoas prefeririam esta tecnologia que parece funcionar de modo semelhante aos humanos, em vez de uma IA geral numa posição de liderança. Os resultados do estudo não corroboraram a hipótese de que a metáfora incluída na RNA iria reduzir a aversão ao algoritmo, pois a única diferença encontrada na aceitação da liderança foi entre o grupo de IA geral e o humano em que o novo líder era uma pessoa normal

    Solid-liquid phase equilibrium: in search of suitable PCMs for low temperature energy storage

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    Centro de Química Estrutural is a Research Unit funded by Fundação para a Ciência e Tecnologia through projects UIDB/00100/2020 and UIDP/00100/2020. • Institute of Molecular Sciences is an Associate Laboratory funded by FCT through project LA/P/0056/2020. • M.C.M. Sequeira acknowledges the PhD grant funded by FCT ref. UI/BD/152239/2021.N/

    Viscosity measurements of compressed ionic liquid EMIM OTf

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    1ª edição do CQE Days, organizada pelo Centro de Química Estrutural, realizada na Academia das Ciências de Lisboa, de 30-31 de maio de 2019 - https://cqe.tecnico.ulisboa.pt/cqedaysIonic liquids have attracted considerable interest in recent years, as they can be used for multiple aims, namely, as antistatic agents, electrolytes, solvents, lubricants, and CO2 absorbents [1]. The use of ionic liquids in industrial processes require their thermophysical properties, in particular, the viscosity and the thermal conductivity. However, transport properties are scarce due to the difficulty of the measurements, particularly at pressures higher than the atmospheric pressure. Our group has developed a programme of measurements aiming at obtaining rigorous results for the viscosity of ionic liquids using the vibrating wire method. This technique, although very accurate for molecular, non-conducting liquids, could have some difficulties with ionic liquids due to their electrical conductivity [2]. As we were planning to use the vibrating wire method in the forced mode of oscillation, the method requires the acquisition of the frequency response of the wire in a range of frequencies containing the velocity resonance for the transverse oscillations of the wire. Therefore, it is important to verify if the ionic liquid sample is a good electrolytic conductor in the range of frequencies that matter for the measurement of viscosity. The problematic of measuring the viscosity of ionic liquids both in general and in particular, using the vibrating wire technique was studied [3]. Pardal et al. [4] have used 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIMOTf) mixed with water as the electrolyte to successfully reduce CO2 at high pressure. The objective of this work is to contribute with viscosity data in the pressure and temperature range of the work performed by those authors. Therefore, we present new ionic viscosity results for temperatures between 298 K and 347 K and pressures up to 50 MPa.N/

    Studying the PEG family

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    1ª edição do CQE Days, organizada pelo Centro de Química Estrutural, realizada na Academia das Ciências de Lisboa, de 30-31 de maio de 2019 - https://cqe.tecnico.ulisboa.pt/cqedaysThe main goal of this line of research is the realisation of experimental measurements of thermophysical properties of a homologous series of ethylene and polyethylene glycols [H(OCH2CH2)nOH], and the development of correlation methods, with an accuracy adequate for the applications. Ethylene glycols and poly (ethylene) glycols (PEG) are widely used in many industrial applications as green solvents and as components of important sustainable processes as they are considered environmentally acceptable compounds [1,2]. Liquid Poly(ethyleneglycols) [PEGs] are in general considered as green solvents. They are non-volatile; their toxicity is very low, such that they are being used as food additives [3]. PEGs have been found to be biodegradable by bacteria in soil or sewage, but the ability of bacteria to biodegrade PEG decreases with increasing molecular weight [3]. The study of this series of compounds is important in many respects, not only because it is aimed at the study of PEGs which have innumerable practical applications but also because this study can be useful to monitor the degree of polymerization in the production of PEGs, themselves. In the present work, the viscosity of three ethylene glycols, namely diethylene, triethylene and tetraethylene glycols [4] and PEG 400 were measured with high accuracy using the vibrating wire technique at moderately high pressures. Complementary experimental density, surface tension and rheological behavior were obtained for the same liquids. One of the aims of the work is to analyse the relation of the present results with those obtained before for CO2 saturated PEG400 mixturesProject UID/QUI/00100/2013 and Project UID/QUI/00100/2019 funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal.N/

    Exploratory study on the viscosity of Poly(ethyleneglycols) and their mixtures with CO2

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    Encontro realizado em Erlangen, a 31 de agosto de 2019.Project UID/QUI/00100/2013 and Project UID/QUI/00100/2019 funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal.N/

    Positive mental health in university students and its relations with psychological vulnerability, mental health literacy, and sociodemographic characteristics: a descriptive correlational study

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    This study aimed to evaluate positive mental health (PMH) and its relation with sociodemographic characteristics, mental health literacy, and the psychological vulnerability scale (PVS) in Portuguese university students aged 17 to 62. A descriptive correlational study was carried out. An online survey was conducted to evaluate demographic variables, and several questionnaires were applied to evaluate positive mental health, psychological vulnerability, and mental health literacy. The data was collected from 1 November 2019 to 1 September 2020. Overall, 3405 students participated in the study. The results show that 67.8% of students revealed a high level of PMH, 31.6% presented a medium level of PMH, and 0.6% had a low level of PMH. Male students reported higher personal satisfaction (t (3170) = −2.39, p = 0.017) and autonomy (t (3170) = −3.33, p = 0.001) in PMH compared to female students. Students without a scholarship scored higher (t (3127) = −2.04, p = 0.42) in PMH than students who held a scholarship. Students who were not displaced from their home reported higher (t (3170) = −1.99, p = 0.047) self-control in PMH than those displaced from their home. University students with higher PMH results had lower PVS results and higher literacy results. The findings of this study will contribute to identifying students’ PMH intervention needs.info:eu-repo/semantics/publishedVersio

    Di-Alkyl adipates as new phase change material for low temperature energy storage

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    This work is a contribution to the thermal characterization of a selected binary system of two di-n-alkyl adipates that can be used as phase change material for thermal energy storage at low temperatures. The construction of the solid–liquid phase diagram using differential scanning calorimetry (DSC), complemented with Raman Spectroscopy studies for the system composed by diethyl and dibutyl adipates is presented. The solidus and liquidus equilibrium temperatures were determined by DSC for the pure components and 30 binary mixtures at selected molar compositions were used to construct the corresponding solid–liquid phase diagram. The binary system of diethyl and dibutyl adipates presents eutectic behaviour at low temperatures. The eutectic temperature was found at 240.46 K, and the eutectic composition was determined to occur at the molar fraction xdibutyl = 0.46. Additionally, the system shows a polymorphic transition, characteristic of dibutyl adipate, occurring at ca. 238 K, confirmed by optical microscopy. To the best of our knowledge, no reference to the phase diagram of the present system could be found in the literature. Raman spectroscopy was essential to complement the construction of the phase equilibrium diagram, enabling the identification of the solid and liquid phases of the system. Finally, the liquidus curve of the phase diagram was also successfully predicted using a suitable fitting equation, being the root mean square deviation of the data from the correlation equal to 0.54 K. In addition, this fitting operation enabled a correct prediction of the eutectic composition of the system.info:eu-repo/semantics/publishedVersio

    Solid-liquid phase equilibrium: alkane systems for low temperature energy storage

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    The incessant and increasing need for energy requires urgent and effective solutions. The supply of renewable energies is mainly intermittent, which often leads to a gap between the availability of energy and its consumption. Therefore, energy storage becomes imperative for increasing the efficiency in the use of the produced energy. Concerning this, the use of phase change materials (PCMs) has taken a very important role, especially for active cooling systems. In particular, eutectic systems can be designed with characteristics that make them suitable for each application, allowing significant energy savings, which is very relevant in what concerns economic and environmental sustainability [1]. This work aims to the characterization of selected systems that can be used for energy storage at low temperatures, starting by the construction of solid-liquid phase diagrams using differential scanning calorimetry (DSC) and Raman Spectroscopy results. Phase diagrams are crucial to characterize the behaviour of these systems and reveals the robustness of the PCM, and for new PCMs, equilibrium studies are essential to achieve the desired melting temperature [2]. This work is focused on binary systems composed by normal alkanes, in particular, the binary mixtures C8-C10 and C10-C12. These systems revealed to behave as eutectic systems at low temperatures, showing a promising applicability for thermal energy storage for low temperature applications. The eutectic points are around -61ºC and -35ºC, respectively. Additionally, a fitting equation for the experimental liquidus lines of the phase equilibrium diagrams is proposed for each system.N/

    Adipates as new phase change material: seeking for a low temperature energy storage system

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    The recent and endless increasing need for energy is requiring imperative and efficient solutions. Renewable energies are an effective solution, but they are also intermittent, which often leads to a gap between the availability of energy and its demand. Therefore, energy storage becomes crucial for improving the efficiency by reducing the mismatch between demand and supply thus offering better management capabilities. The use of phase change materials (PCMs) became an attractive technology, especially for active cooling systems. In particular, eutectic systems can be designed for each application, allowing significant energy savings, which is very relevant in what concerns economic and environmental sustainability [1]. Equilibrium studies and their phase diagrams are crucial to characterize the behavior of these systems, particularly for new PCMs [2]. This work aims the characterization of a selected type of binary system composed by di-n-alkyl adipates that can be used for energy storage at low temperatures, starting by the construction of solid-liquid phase diagram based on Differential Scanning Calorimetry (DSC) and Raman Spectroscopy results. The studied system is a binary mixture of diethyl and dibutyl adipates and reveals to behave as a eutectic system at low temperatures, possessing also polymorphism, therefore presenting a relatively complex phase diagram. The eutectic point was found around -33ºC and the polymorphism transition, being characteristic of the dibutyl adipate, occurs at around -36ºC for the overall phase diagram. Raman spectroscopy was fundamental concerning the construction of the phase diagram, enabling to identify the different solid and liquid phases of the system. This work provides new phase equilibrium data, which, to the knowledge of the authors, are the first in the literature, concerning these compounds. The studied binary system has promising characteristics for low temperature energy storage. It is also demonstrated how solid-liquid-phase equilibrium studies are the key to select the most appropriate phase change material for a specific thermal energy storage (TES) application.N/
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