1,491 research outputs found

    Uncertainty Analysis of Feature Extraction from Expired Gas Traces

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    Noninvasive medical analyses are a convenient method to study several pathologies even though their indirect nature often requires a complex processing to determine the relevant health "indicators". The usefulness of such indicators depends on the employed model, but also on the uncertainty that is connected to the complex processing involved in the indicator determination. This paper deals with the problems related to the estimation of the uncertainty when the indicators are computed by means of a nontrivial processing on recorded traces of clinical parameters. The paper is focused on the analysis of expired gas traces, but the procedure can also be applied to many other cases where the processing involves manual or automatic selection of suitable "key points" on repetitive traces

    Model Predictive Control Strategies for Advanced Battery Management Systems

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    Consumer electronics, wearable and personal health devices, power networks, microgrids, and hybrid electric vehicles (HEVs) are some of the many applications where Lithium-ion (Li-ion) batteries are employed. From a manufacturer point of view, the optimal design and management of such electrochemical accumulators are important aspects for ensuring safe and profitable operations. The adoption of mathematical models can support the achievement of the best performance, while saving time and money. In the literature, all the models used to describe the behavior of a Li-ion battery belong to one of the two following families: (i) Equivalent Circuit Models (ECMs), and (ii) Electrochemical Models (EMs). While the former family represents the battery dynamics by means of electrical circuits, the latter resorts to first principles laws of modeling. As a first contribution, this Thesis provides a thorough investigation of the pseudo-two-dimensional (P2D) Li-ion battery EM. In particular, the objectives are to provide: (i) a detailed description of the model formulation, (ii) the Li-ION SIMulation BAttery (LIONSIMBA) toolbox as a finite volume Matlab implementation of the P2D model, for design, simulation, and control of Li-ion cells or battery packs, (iii) a validation of the proposed tool with respect to the COMSOL MultiPhysics commercial software and the Newman's DUALFOIL code, and (iv) some demonstrative simulations involving thermal dynamics, a hybrid charge-discharge cycle emulating the throttle of an HEV, and a battery pack of series connected cells. The second contribution is related to the development of several charging strategies for Advanced Battery Management Systems (ABMSs), where predictive approaches are employed to attain optimal control. Model Predictive Control (MPC) refers to a particular family of control algorithms that, according to a mathematical model, predicts the future behavior of a plant, while considering inputs and outputs constraints. According to this paradigm, in this Thesis different ABMSs strategies have been developed, and their effectiveness shown through simulations. Due to the complexity of the P2D model, its inclusion within an MPC context could prevent the online application of the control algorithm. For this reason, different approximations of the P2D dynamics are proposed and their MPC formulations carefully explained. In particular, finite step response, autoregressive exogenous, piecewise affine, and linear time varying approximations are presented. For all the aforementioned reformulations, the closed-loop performance are evaluated considering the P2D implementation of LIONSIMBA as the real plant. The closed-loop simulations highlight the suitability of the MPC paradigm to be employed for the development of the future ABMSs. In fact, its ability to predict the future behavior of the cell while considering operating constraints can help in preventing possible safety issues and improving the charging performance. Finally, the reliability and efficiency of the proposed Matlab toolbox in simulating the P2D dynamics, support the idea that LIONSIMBA can significantly contribute in the advance of the battery field.Consumer electronics, wearable and personal health devices, power networks, microgrids, and hybrid electric vehicles (HEVs) are some of the many applications where Lithium-ion (Li-ion) batteries are employed. From a manufacturer point of view, the optimal design and management of such electrochemical accumulators are important aspects for ensuring safe and profitable operations. The adoption of mathematical models can support the achievement of the best performance, while saving time and money. In the literature, all the models used to describe the behavior of a Li-ion battery belong to one of the two following families: (i) Equivalent Circuit Models (ECMs), and (ii) Electrochemical Models (EMs). While the former family represents the battery dynamics by means of electrical circuits, the latter resorts to first principles laws of modeling. As a first contribution, this Thesis provides a thorough investigation of the pseudo-two-dimensional (P2D) Li-ion battery EM. In particular, the objectives are to provide: (i) a detailed description of the model formulation, (ii) the Li-ION SIMulation BAttery (LIONSIMBA) toolbox as a finite volume Matlab implementation of the P2D model, for design, simulation, and control of Li-ion cells or battery packs, (iii) a validation of the proposed tool with respect to the COMSOL MultiPhysics commercial software and the Newman's DUALFOIL code, and (iv) some demonstrative simulations involving thermal dynamics, a hybrid charge-discharge cycle emulating the throttle of an HEV, and a battery pack of series connected cells. The second contribution is related to the development of several charging strategies for Advanced Battery Management Systems (ABMSs), where predictive approaches are employed to attain optimal control. Model Predictive Control (MPC) refers to a particular family of control algorithms that, according to a mathematical model, predicts the future behavior of a plant, while considering inputs and outputs constraints. According to this paradigm, in this Thesis different ABMSs strategies have been developed, and their effectiveness shown through simulations. Due to the complexity of the P2D model, its inclusion within an MPC context could prevent the online application of the control algorithm. For this reason, different approximations of the P2D dynamics are proposed and their MPC formulations carefully explained. In particular, finite step response, autoregressive exogenous, piecewise affine, and linear time varying approximations are presented. For all the aforementioned reformulations, the closed-loop performance are evaluated considering the P2D implementation of LIONSIMBA as the real plant. The closed-loop simulations highlight the suitability of the MPC paradigm to be employed for the development of the future ABMSs. In fact, its ability to predict the future behavior of the cell while considering operating constraints can help in preventing possible safety issues and improving the charging performance. Finally, the reliability and efficiency of the proposed Matlab toolbox in simulating the P2D dynamics, support the idea that LIONSIMBA can significantly contribute in the advance of the battery field

    Energy-Exergy, Environmental and Economic Criteria in Combined Heat and Power (CHP) Plants: Indexes for the Evaluation of the Cogeneration Potential

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    In the first part of this work, combined heat and power (CHP) criteria pertaining to energy, exergy, environmental (pollutant emission) and economic aspects, have been investigated and compared. Although the constraints in legislation usually refer to energy efficiency, primary energy savings and greenhouse gas savings, other criteria should also be taken into account in order to obtain a better evaluation of a cogeneration plant. Here particular attention has been paid to saving indexes for both an individual CHP-unit and for a CHP-system, that is the complete system with all the cogeneration units and the auxiliary plants necessary to cover the users' demand. Five indexes, named potential indexes, have been introduced to evaluate the cogeneration potential: one for energy saving, one for exergy, two for environmental aspects (global and local scale) and one for economic aspects. Finally, some indexes analysed in the paper have been applied to a case study concerning a district heating cogeneration system, and the different behaviour of the energy-exergy, environmental and economic aspects has been discussed

    The ethology of the wasp, Pseudomasaris Edwardsii (Cresson), and a description of its immature forms (Hymenoptera: Vespoidea, Masaridae)

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    In a greenhouse, each nest of Pseudomasaris edwardsii (Cresson) was constructed of nectar-moistened soil, was solitary and was placed in open but concealed niches attached to a variety of substrates. The wasp anchored her egg by its posterior tip to the bottom of the cell, deposited a jellylike cylindrical provision composed of Phacelia pollen and nectar and constructed a cell cap. Soil carried to the nest was attached to the post genal surfaces of the female\u27s head, and the pollen and nectar were transported in her honey stomach. Cells were clustered and attached to each other and to the substrate along their lateral margins. Most nests were covered with separate layers of soil (surface ornamented in various ways) that camouflaged the nest against natural enemies and protected it against extreme temperatures. The larva, after consuming its provision, spun a cocoon which closely adhered to the inner surface of the cell, and then voided its feces across the bottom of the cell. The post-defecated larva subsequently migrated to the anterior limit of the cell where it firmly appressed against the cocoon as it assumed a strongly decurved, overwintering, prepupal position. Rearings in the laboratory indicated that the species is univoltine and nonproterandrous. The immature forms of P. edwardsii and Euparagia scutellaris Cresson are described and represent the first descriptions of the immatures within the family Masaridae. Relationship of these immatures is discussed and both are compared with the immature forms of other known vespoids

    Fast model predictive control for hydrogen outflow regulation in ethanol steam reformers

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    © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In the recent years, the presence of alternative power sources, such as solar panels, wind farms, hydropumps and hydrogen-based devices, has significantly increased. The reasons of this trend are clear: contributing to a reduction of gas emissions and dependency on fossil fuels. Hydrogen-based devices are of particular interest due to their significant efficiency and reliability. Reforming technologies are among the most economic and efficient ways of producing hydrogen. In this paper we consider the regulation of hydrogen outflow in an ethanol steam reformer (ESR). In particular, a fast model predictive control approach based on a finite step response model of the process is proposed. Simulations performed using a more realistic non-linear model show the effectiveness of the proposed approach in driving the ESR to different operating conditions while fulfilling input and output constraints.Peer ReviewedPostprint (author's final draft

    Comparative Notes on the Biology and Development of \u3ci\u3eEpeolus compactus\u3c/i\u3e Cresson., a Cleptoparasite of \u3ci\u3eColletes kincaidii\u3c/i\u3e Cockerell (Hymenoptera: Anthophoridae, Colletidae)

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    The biology of the nomadine bee, Epeolus compactus Cresson, is described based on composite notes taken from field, laboratory, and greenhouse studies of the host bee, Colletes kincaidii Cockerell. Details of Epeolus egg deposition are described and compared with other known noma dine bees. We document the release of a glandular secretion during egg deposition by E. compactus which dissolves the polyester host cell lining on contact. Late embryogenesis and hatching of Epeolus are described and adaptive features are discussed. The cleptoparasitic habits of the first instar are outlined, and anatomical differences expressed by various ins tars are compared. Methods used by Epeolus in parasitizing host nests excavated by the nesting Colletes female, or in host nests constructed in existing burrows, are reported. Possible reasons why rates of parasitism differ between kinds of nest architectures constructed by the host bee are discussed in some detail. Potentially useful biosystematic characters of immature stages of Epeolus are compared with those of other known nomadine bees

    The Strategic Value of Information: A Manager\u27s Guide to Profiting from Information Systems

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    The unprecedented volume of data captured by modern hospitality firms can be used to create economic value. This report provides a methodology to help hospitality managers identify and prioritize possible data-driven initiatives. This process starts with identifying the transaction-processing systems in the organization and inventorying the data they capture and store. After envisioning possible initiatives that employ these data, the methodology suggests a way to prioritize projects to ensure that only those offering positive returns are implemented. The methodology presented here allows managers to make such a cost-benefit assessment for any data-driven initiative

    Economic and Human Features for Energy and Environmental Indicators: A Tool to Assess Countries’ Progress towards Sustainability

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    Energy and environmental data represent fundamental information for the analysis of sustainable development. On the other hand, these aspects should be associated with economic and human dimensions in order to obtain a more holistic vision. From this perspective, some indicators are discussed and analyzed in this paper in order to assess the performance of a country. As regards the energetic aspects, the data of total primary energy supply and exergy losses were considered. The environmental aspects were taken into account by considering the greenhouse gas emissions and the particulate matter emissions. These energy and environmental data were put in relation to the GDP (gross domestic product) and HDI (human development index, a multidimensional index proposed by United Nations), respectively. So, two sets of indicators were introduced—the set E for economic properties and the set H for human aspects. A case study was conducted by analyzing a group of countries that meet two criteria: the same macro-geographical area and comparable numbers of citizens. The European area—in particular, its six most populous countries—was chosen. From the results obtained, it is possible to point out that some countries present different rankings depending on whether set E or set H is considered. Another important aspect discussed is the temporal evolution of the indicators (the interval from 1990 to 2017 was considered). Political decision-makers can be supported by the use of the indicators of set H in order to evaluate well-being related to their choices on actions related to the energy and environment. These indicators can be used both to analyze the trends of a country and to compare them with the performance of some other similar countries

    Mixed Neural-Conventional Processing to Differentiate Airway Diseases by Means of Functional Noninvasive Tests

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    This paper describes a processing technique that can be used to combine information from different medical analyze to discriminate between different pathologies that have similar symptoms. The paper is focused on the differentiation between asthma, bronchitis, and emphysema, using only functional noninvasives tests, but the proposed technique can be easily applied to other similar situations where different tests have to be used to identify a pathology. The technique is based on mixed neural-and-conventional processing that not only suggests the pathology, but also estimates the reliability of this suggestion
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