8,948 research outputs found
Combining shallow-water and analytical wake models for tidal-array micro-siting
For tidal-stream energy to become a competitive renewable energy source, clustering multiple turbines into arrays is paramount. Array optimisation is thus critical for achieving maximum power performance and reducing cost of energy. However, ascertaining an optimal array layout is a complex problem, subject to specific site hydrodynamics and multiple inter-disciplinary constraints. In this work, we present a novel optimisation approach that combines an analytical-based wake model, FLORIS, with an ocean model, Thetis. The approach is demonstrated through applications of increasing complexity. By utilising the method of analytical wake superposition, the addition or alteration of turbine position does not require re-calculation of the entire flow field, thus allowing the use of simple heuristic techniques to perform optimisation at a fraction of the computational cost of more sophisticated methods. Using a custom condition-based placement algorithm, this methodology is applied to the Pentland Firth for arrays with turbines of 3.05m/s rated speed, demonstrating practical implications whilst considering the temporal variability of the tide. For a 24-turbine array case, micro-siting using this technique delivered an array 15.8% more productive on average than a staggered layout, despite flow speeds regularly exceeding the rated value. Performance was evaluated through assessment of the optimised layout within the ocean model that treats turbines through a discrete turbine representation. Used iteratively, this methodology could deliver improved array configurations in a manner that accounts for local hydrodynamic effects
Annals [...].
Pedometrics: innovation in tropics; Legacy data: how turn it useful?; Advances in soil sensing; Pedometric guidelines to systematic soil surveys.Evento online. Coordenado por: Waldir de Carvalho Junior, Helena Saraiva Koenow Pinheiro, Ricardo Simão Diniz Dalmolin
Foundations for programming and implementing effect handlers
First-class control operators provide programmers with an expressive and efficient
means for manipulating control through reification of the current control state as a first-class object, enabling programmers to implement their own computational effects and
control idioms as shareable libraries. Effect handlers provide a particularly structured
approach to programming with first-class control by naming control reifying operations
and separating from their handling.
This thesis is composed of three strands of work in which I develop operational
foundations for programming and implementing effect handlers as well as exploring
the expressive power of effect handlers.
The first strand develops a fine-grain call-by-value core calculus of a statically
typed programming language with a structural notion of effect types, as opposed to the
nominal notion of effect types that dominates the literature. With the structural approach,
effects need not be declared before use. The usual safety properties of statically typed
programming are retained by making crucial use of row polymorphism to build and
track effect signatures. The calculus features three forms of handlers: deep, shallow,
and parameterised. They each offer a different approach to manipulate the control state
of programs. Traditional deep handlers are defined by folds over computation trees,
and are the original con-struct proposed by Plotkin and Pretnar. Shallow handlers are
defined by case splits (rather than folds) over computation trees. Parameterised handlers
are deep handlers extended with a state value that is threaded through the folds over
computation trees. To demonstrate the usefulness of effects and handlers as a practical
programming abstraction I implement the essence of a small UNIX-style operating
system complete with multi-user environment, time-sharing, and file I/O.
The second strand studies continuation passing style (CPS) and abstract machine
semantics, which are foundational techniques that admit a unified basis for implementing deep, shallow, and parameterised effect handlers in the same environment. The
CPS translation is obtained through a series of refinements of a basic first-order CPS
translation for a fine-grain call-by-value language into an untyped language. Each refinement moves toward a more intensional representation of continuations eventually
arriving at the notion of generalised continuation, which admit simultaneous support for
deep, shallow, and parameterised handlers. The initial refinement adds support for deep
handlers by representing stacks of continuations and handlers as a curried sequence of
arguments. The image of the resulting translation is not properly tail-recursive, meaning some function application terms do not appear in tail position. To rectify this the
CPS translation is refined once more to obtain an uncurried representation of stacks
of continuations and handlers. Finally, the translation is made higher-order in order to
contract administrative redexes at translation time. The generalised continuation representation is used to construct an abstract machine that provide simultaneous support for
deep, shallow, and parameterised effect handlers. kinds of effect handlers.
The third strand explores the expressiveness of effect handlers. First, I show that
deep, shallow, and parameterised notions of handlers are interdefinable by way of typed
macro-expressiveness, which provides a syntactic notion of expressiveness that affirms
the existence of encodings between handlers, but it provides no information about the
computational content of the encodings. Second, using the semantic notion of expressiveness I show that for a class of programs a programming language with first-class
control (e.g. effect handlers) admits asymptotically faster implementations than possible in a language without first-class control
How to Be a God
When it comes to questions concerning the nature of Reality, Philosophers and Theologians have the answers.
Philosophers have the answers that can’t be proven right. Theologians have the answers that can’t be proven wrong.
Today’s designers of Massively-Multiplayer Online Role-Playing Games create realities for a living. They can’t spend centuries mulling over the issues: they have to face them head-on. Their practical experiences can indicate which theoretical proposals actually work in practice.
That’s today’s designers. Tomorrow’s will have a whole new set of questions to answer.
The designers of virtual worlds are the literal gods of those realities. Suppose Artificial Intelligence comes through and allows us to create non-player characters as smart as us. What are our responsibilities as gods? How should we, as gods, conduct ourselves?
How should we be gods
Radionuclide and heavy metal sorption on to functionalised magnetic nanoparticles for environmental remediation
The presence of radionuclides and heavy metal ions in aqueous waste streams from industrial processes, especially in the nuclear waste industry, are a major concern. Many other processes are inherent producers of hazardous aqueous waste streams that require treatment for further disposal. These wastes quite often contain many contaminants, from harmful to very toxic. Contact with the environment, through groundwater or rivers, with such contaminants needs to be avoided. The ability to selectively sequester and remove contaminants from aqueous wastes with high loading capacities is of paramount importance to achieve full removal of the contaminants produced in many industries. The recent development of phosphate functionalised superparamagnetic magnetite ((PO)x-Fe3O4) nanoparticles have been shown to have ultra-high loading capacities and a high degree of selectivity towards uranium (U(VI)). The ability to manipulate these NPs with an external magnetic field gives these nanomaterials an advantage over many other conventional technologies in the field. These low-cost, non-toxic, and easily prepared magnetic NPs are highly biocompatible and have already been widely applied in the biotechnology and biomedical industries. The addition of specific functionalities allows for the fine tuning of the selectivity towards certain elements, therefore allowing full control over the selective removal of a wide range of contaminants. This study addresses the optimisation of the NPs manufacturing process that allows for the use of these NPs in a wider range of environments. Many of these waste streams are extreme environments, where they can be highly acidic or highly basic conditions. Therefore the feasibility of coating the Fe3O4 with silica (SiO2) was addressed, to provide an acid resistant layer and substrate for further functionalisation. Both the silica coating, and the applied surface functionality, were found to be stable against dissolution or chemical changes under acidic conditions from pH 1-4. Once acid resistance was established, the ability to extract a wide range of contaminant ions was also investigated. Sorption experiments with a wide range of contaminant ions were conducted to determine the selectivity and loading capacities of both (PO)x-Fe3O4 and (PO)x-SiO2@Fe3O4 NPs, at acidic (pH 3), neutral (pH 7), and basic (pH 11) conditions. Providing a basis for the manufacture of a state-of-the-art, novel extraction tool for both heavy metals and radionuclides. Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy - Energy Dispersive X-Ray (STEM-EDX) were used to achieve full characterisation of the NP complexes and supernatants to determine the successful extraction and presence of the contaminant metal ions used in this study. Determining the uptake kinetics, loading capacities for Cs(I), K(I), Na(I), Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Mo(II), Ni(II), Pb(II), Sr(II), Al(III), Ce(III), Cr(III), Eu(III), Fe(III) and La(III) on to (PO)x-Fe3O4 and (PO)x-SiO2@Fe3O4 NPs. Implications of the use of these NPs in the extraction of radionuclides and heavy metals have been discussed in each case along with the potential for developing a broad-spectrum adsorbent. In conclusion, this PhD has shown the potential of these novel as-synthesised phosphate functionalised NP complexes to be utilised for heavy metal and radionuclide extraction, of a range of contaminants, from aqueous solutions, in acidic, neutral, and basic conditions. The production of these cost-effective and selective nanomaterials which exhibit rapid kinetics has the potential to be an important asset to the water treatment industry. Overall, these NP-complexes have been effective in fully removing a wide range of heavy metal contaminants and, therefore, have shown great promise to become a broad-spectrum adsorbent tool, which ultimately will aid in the clean-up of many new and legacy waste environments.Open Acces
Stimulating Non‐Energy Exports in Trinidad and Tobago: Evidence from a Small Petroleum‐Exporting Economy Experiencing the Dutch Disease
The motivation for this study hinges around the fact that Trinidad and Tobago (T&T) is suffering from the Dutch disease which inadvertently hinders the growth of non-energy exports. This paper examines measures that can be adopted for a small petroleum-exporting economy to dampen the effect of Dutch disease by promoting non-energy trade. This paper is novel and contributes to the literature in using panel data for the T&T case, as it investigates the effect of a devaluation of the TT dollar in order to stimulate non-energy exports (a combination of agriculture and manufacturing trade). Note that previous studies would have examined the Marshall–Lerner condition on the aggregate trade balance which is heavily influenced by energy revenues. The panel autoregressive distributed lag (ARDL) method is used for ten of T&T’s main trading partners for the period 1991 to 2019 to establish findings. The results show that the Marshall–Lerner condition does not hold for aggregate trade in the long run, as expected. However, when non-energy trade is isolated, it is found that a devaluation of the TT dollar does have a positive impact on non-energy trade and the Marshall–Lerner condition holds. Other measures are also recommended to stimulate non-energy exports in the long run
Excess foundry sand characterization and experimental investigation in controlled low-strength material and hot-mixing asphalt
This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: a statistically sound evaluation of the characterization of foundry sand, a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at Nini, Ndes, and Nmax. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.Structural Engineerin
Parametric software effort estimation based on optimizing correction factors and multiple linear regression
Context: Effort estimation is one of the essential phases that must be accurately predicted in the early stage of software project development. Currently, solving problems that affect the estimation accuracy of Use Case Points-based methods is still a challenge to be addressed. Objective: This paper proposes a parametric software effort estimation model based on Optimizing Correction Factors and Multiple Regression Models to minimize the estimation error and the influence of unsystematic noise, which has not been considered in previous studies. The proposed method takes advantage of the Least Squared Regression models and Multiple Linear Regression models on the Use Case Points-based elements. Method: We have conducted experimental research to evaluate the estimation accuracy of the proposed method and compare it with three previous related methods, i.e., 1) the baseline estimation method – Use Case Points, 2) Optimizing Correction Factors, and 3) Algorithmic Optimization Method. Experiments were performed on datasets (Dataset D1, Dataset D2, and Dataset D3). The estimation accuracy of the methods was analysed by applying various unbiased evaluation criteria and statistical tests. Results: The results proved that the proposed method outperformed the other methods in improving estimation accuracy. Statistically, the results proved to be significantly superior to the three compared methods based on all tested datasets. Conclusion: Based on our obtained results, the proposed method has a high estimation capability and is considered a helpful method for project managers during the estimation phase. The correction factors are considered in the estimation process. AuthorFaculty of Applied Informatics, Tomas Bata University in Zlin [IGA/CebiaTech/2021/001, RO30216002025
Achieving human and ecological well-being through sustainable development goals (SDGs) : a case study of Iran
Doutoramento em Estudos de DesenvolvimentoThis thesis investigates on the contribution of Sustainable Development Goals (SDGs) in transitioning toward an economy based on human and ecological well-being. This thesis has developed in two parts: Part One focuses on the literature review of the Human and Ecological Well-being and the SDGs, which provides the theoretical basis for Part Two, which focuses on Systems Dynamics Model of SDGs for Iran, which explores the research questions through an empirical inquiry.
In the theoretical part, it reviews the conceptions of human and ecological well-being from an interdisciplinary perspective. Further it analyzes the role of SDGs in transitioning toward an economy based on human and ecological well-being. Then based on thermodynamics model of sustainability, and end-means continuum of Daly (1991) it proposes a conceptual framework which considers the interactions among goals of SDGs and distinguishes between means and ends which enhances the contribution of SDGs to human and ecological well-being.
The empirical part of this thesis measures this transition through presenting a systems dynamics model of four SDGs (SDG-1, SDG-8, SDG-12, and SDG-13) for Iran. The model is used to generate four possible stories about the implementation of SDGs in the future of Iranian economy from 2020 to 2050: two conventional scenarios (Business as Usual, and Inclusive Growth), and two transformational ones (Steady State Economy, and Well-being for People and Planet). The performance of the Iranian economy for progressing SDGs is monitored through four SDGs Indexes, and a Combined Index of four SDGs. The results of the simulation of the SDGs model of Iran shows that transformational scenarios provide better pathway in comparison to conventional scenarios for achieving SDGs. This thesis concludes that new economic system that is based on transformational policy changes and extraordinary efforts are required for progress in achieving SDGs and delivering human and ecological well-being.Esta tese investiga a contribuição dos Objetivos de Desenvolvimento Sustentável (ODS) na transição para uma economia baseada no bem-estar humano e ecológico. Este estudo identifica três questões principais de pesquisa (RQs): RQ1) Como contribuir para a transição de uma economia baseada no crescimento econômico para uma baseada no bem-estar humano e ecológico? RQ2) Como a Agenda 2030 da ONU de ODS se relaciona e contribui para o bem-estar humano e ecológico? RQ3) Os ODS selecionados poderiam ser alcançados no Irã até 2050 por meio de uma abordagem integrada para melhorar o bem-estar humano e ecológico? Para responder a essas perguntas, o presente trabalho é composto por duas partes: a primeira parte enfoca teoricamente no Bem-estar Humano e Ecológico e nos ODS. A segunda parte é constituído pela elaboração de um Modelo em Sistemas Dinâmicos sobre os ODS, que procura explorar as questões de pesquisa por meio uma investigação empírica. Destaca-se que as duas partes são complementares. A parte teórica revisa as concepções de bem-estar humano e ecológico em uma perspectiva interdisciplinar. Este estudo se baseia na discussão do bem-estar humano que vai além dos aspectos meramente econômicos e explica que o bem-estar humano e ecológico estão inter-relacionados e a importância do mesmo. É explorado os aspectos multidimensionais do bem-estar humano e ecológico e os categoriza em três aspectos inter-relacionados de social, econômico e ambiental. Esta pesquisa considera o bem-estar humano e ecológico para enfatizar o fato de que o bem-estar humano depende do bem-estar ecológico. Portanto, permanecer dentro dos limites planetários é essencial para alcançar o bem-estar humano. Além disso, ele revisa a compreensão e a interpretação do bem-estar na literatura iraniana e, em seguida, compara-a com a literatura de língua inglesa convencional. Através da revisão da literatura com o continuum fins-meios de Daly (1991) em seu centro, esta tese acrescenta às críticas existentes sobre a consideração do crescimento econômico como o objetivo principal da economia dominante, o que ainda leva à proposição de uma estrutura. considerar o bem-estar humano e ecológico como o objetivo final da economia. Essa revisão ajudou a fortalecer as críticas existentes ao crescimento econômico como o objetivo final da economia do ponto de vista da sustentabilidade e do bem-estar. Ainda que muitos países desenvolvidos e em desenvolvimento continuem a pensar no crescimento econômico como o objetivo final de suas economias, este estudo junta-se aos apelos para uma transição de meramente considerar o crescimento econômico como o objetivo final em direção a uma economia baseada no bem-estar humano e ecológico. Além disso, analisa o papel de agendas alternativas (além do PIB, decrescimento e economia de estado estacionário e metas globais), com foco específico nos ODS, na transição para uma economia baseada no bem-estar humano e ecológico. Portanto, ele se concentra nos desafios e riscos que enfrentamos na implementação dos ODS. Esta pesquisa explica as críticas existentes sobre os ODS em relação à obtenção do bem-estar humano e ecológico, incluindo 1) ser baseado no modelo de três pilares de sustentabilidade, 2) desconsiderar as interações entre objetivos e metas (Costanza, Daly, et al. 2016a; ICSU 2017; Nilson et al. 2016, e 3) ausência de um objetivo final (Costanza, Daly, et al. 2016a; ICSU e ISSC, 2015). Em seguida, com base no modelo termodinâmico de sustentabilidade, e meio-fim continuum de Daly (1991), ele propõe um quadro conceitual que considera as interações entre os objetivos dos ODS e distingue entre meios e fins o que aumenta a contribuição dos ODS para o bem-estar humano e ecológico. A estrutura do contínuo fins-meios fornece uma base sólida para defender o “bem-estar humano e ecológico” como o objetivo final desejável. A parte empírica do presente trabalho mede essa transição através da apresentação de um modelo de sistemas dinâmicos composto por quatro ODS (ODS-1 (Sem Pobreza), ODS-8 (Crescimento Econômico e Trabalho Decente), ODS-12 (Consumo e Produção Sustentáveis) e ODS -13 (Ação Climática)) para o Irã. O modelo é usado para gerar quatro cenários possíveis sobre a implementação dos ODS no futuro da economia iraniana de 2020 a 2050: dois cenários convencionais (Business as usual e Crescimento Inclusivo) que são baseados em políticas convencionais, e dois transformacionais (Economia Estacionária e Bem-estar para as Pessoas e o Planeta) que se baseiam em políticas transformacionais. 1) Cenário de Business as usual apenas projeta as tendências atuais no futuro, 2) Cenário de crescimento inclusivo é projetado para ter mais igualdade de renda e crescimento econômico mais rápido, no cenário Estado Estacionário medidas são introduzidas para melhorar o aspectos sociais e ambientais, embora tenha crescimento econômico zero, e 4) Cenário de Bem-estar para as Pessoas e o Planeta é projetado para melhorar os aspectos socioeconômicos e ambientais da economia iraniana para alcançar os ODS no Irã. O desempenho da economia iraniana para o progresso dos ODS é monitorado por meio de quatro índices de ODS que são medidos com base na média aritmética dos indicadores selecionados para cada ODS, que incluem pobreza, crescimento do PIB, desigualdade de renda, taxa de desemprego, trabalho decente, proporção de investimento em energia renovável para PIB, emissões de CO2 e pegada ecológica, que contribuem para o objetivo final do bem-estar humano e ecológico. Para mensurar de forma mais amplas os cenários projetados sobre a implementação desses quatro ODS, um Índice Combinado de quatro Índices ODS é medido com base na média aritmética dos índices do ODS-1, ODS-8, ODS-12 e o SDG-13. O Índice Combinado de quatro ODS mostra, em média, qual dos cenários oferece um caminho melhor para atingir esses quatro ODS. A análise de tais índices pode ajudar a informar a formulação de políticas sociais, econômicas e ambientais no Irã. Os resultados das simulações mostram que nos cenários convencionais o Índice Combinado de quatro ODS está diminuindo ao longo do tempo em comparação com o ano base de 2020. Por outro lado, o Índice Combinado de quatro ODS em cenários transformacionais melhora futuramente em comparação ao ano base 2020. Dentre esses quatro cenários, o cenário de Bem-estar para as Pessoas e o Planeta oferece o melhor caminho possível para o alcance dos ODS. Além disso, o modelo de ODS do Irã analisa a implementação dos ODS por meio de uma economia estacionária, cujos resultados ilustram que fornece um caminho melhor para atingir os ODS em comparação com os cenários convencionais. Portanto, os resultados da simulação do modelo de ODS do Irã mostram que os cenários transformacionais fornecem um caminho melhor em comparação com os cenários convencionais para atingir os ODS. Isso significa que políticas transformacionais e mudanças no sistema econômico atual são necessárias para cumprir os ODS.
Este estudo conclui que os ODS têm potencial para contribuir para o bem-estar humano e ecológico, no entanto, sua contribuição poderia ser maior se for baseada em uma abordagem de sustentabilidade forte, distinguindo entre meios e objetivos e definindo um objetivo final. Os ODS são metas ambiciosas e, portanto, alcançá-los até 2030 é muito difícil, especialmente em países em desenvolvimento que enfrentam falta de recursos financeiros, infraestrutura, etc. O Irã está enfrentando alguns obstáculos na implementação dos ODS, incluindo a implementação fraca e desorganizada dos planos, além de negligenciar as interações entre três sistemas de economia, sociedade e meio ambiente, falta de energia renovável, falta de consciência ambiental, falta de dados de alta qualidade e visões paradoxais na implementação dos ODS da ONU no Irã. O presente estudo conclui que um novo sistema econômico baseado em mudanças de política transformacional e esforços extraordinários são necessários para o progresso no alcance dos ODS. Essa transformação no sistema econômico preenche a lacuna entre três sistemas de economia, sociedade e meio ambiente, ao prestar atenção detalhada às interações entre os objetivos dos ODS. Atualmente, estamos enfrentando questões complexas como mudanças climáticas, desigualdades, etc. que não podem ser resolvidas se considerarmos o crescimento como um objetivo final da economia. Portanto, ter uma perspectiva de pensamento sistêmico é necessário para ser capaz de enfrentar todas as crises. É necessário passar de uma economia baseada no crescimento econômico para uma economia baseada no bem-estar humano e ecológico.info:eu-repo/semantics/publishedVersio
Three-dimensional forward modelling and inversion for the CSAMT method using unstructured grids
Three-dimensional forward-modelling and inversion problems are investigated for the
controlled-source audio-frequency magnetotelluric (CSAMT) method and both
forward-modelling and inversion codes written. The finite-element (FE) method,
which is a numerical method for obtaining approximate solutions to boundary-value
problems, is used for forward modelling. A potential formulation, specifically the
decomposition of the electric field into vector and scalar potentials for the Helmholtz
and the conservation of charge equations, is used. Vector and scalar basis functions
are used for the potentials. The equations are discretized using the weighted residual
method, which results in a sparse linear system. Modelling domains are subdivided
into unstructured tetrahedral grids. The linear system is solved by the direct solver,
MUMPS, with LU factorization. A number of examples are presented for the
validation of the code. A minimum-structure method with Gauss-Newton iterations is
used for the inversion. Iterative preconditioned conjugate gradient and
nonpreconditioned generalized minimal residual methods are used to solve the linear
systems of equations for the model updates. These solvers do not request explicit
calculations of the matrices; therefore, this significantly reduces memory demand.
Three benchmark tests are presented to verify the inversion code
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