126 research outputs found
A geo-informatics approach to sustainability assessments of floatovoltaic technology in South African agricultural applications
South African project engineers recently pioneered the first agricultural floating solar photovoltaic tech nology systems in the Western Cape wine region. This effort prepared our country for an imminent large scale diffusion of this exciting new climate solver technology. However, hydro-embedded photovoltaic sys tems interact with environmentally sensitive underlying aquatic ecosystems, causing multiple project as sessment uncertainties (energy, land, air, water) compared to ground-mounted photovoltaics. The dissimi lar behaviour of floatovoltaic technologies delivers a broader and more diversified range of technical advan tages, environmental offset benefits, and economic co-benefits, causing analytical modelling imperfections
and tooling mismatches in conventional analytical project assessment techniques. As a universal interna tional real-world problem of significance, the literature review identified critical knowledge and methodology
gaps as the primary causes of modelling deficiencies and assessment uncertainties. By following a design thinking methodology, the thesis views the sustainability assessment and modelling problem through a geo graphical information systems lens, thus seeing an academic research opportunity to fill critical knowledge
gaps through new theory formulation and geographical knowledge creation. To this end, this philosophi cal investigation proposes a novel object-oriented systems-thinking and climate modelling methodology to
study the real-world geospatial behaviour of functioning floatovoltaic systems from a dynamical system thinking perspective. As an empirical feedback-driven object-process methodology, it inspired the thesis to
create new knowledge by postulating a new multi-disciplinary sustainability theory to holistically characterise
agricultural floatovoltaic projects through ecosystems-based quantitative sustainability profiling criteria. The
study breaks new ground at the frontiers of energy geo-informatics by conceptualising a holistic theoretical
framework designed for the theoretical characterisation of floatovoltaic technology ecosystem operations
in terms of the technical energy, environmental and economic (3E) domain responses. It campaigns for a
fully coupled model in ensemble analysis that advances the state-of-the-art by appropriating the 3E theo retical framework as underpinning computer program logic blueprint to synthesise the posited theory in a
digital twin simulation. Driven by real-world geo-sensor data, this geospatial digital twin can mimic the geo dynamical behaviour of floatovoltaics through discrete-time computer simulations in real-time and lifetime
digital project enactment exercises. The results show that the theoretical 3E framing enables project due
diligence and environmental impact assessment reporting as it uniquely incorporates balanced scorecard
performance metrics, such as the water-energy-land-food resource impacts, environmental offset benefits
and financial feasibility of floatovoltaics. Embedded in a geoinformatics decision-support platform, the 3E
theory, framework and model enable numerical project decision-supporting through an analytical hierarchy
process. The experimental results obtained with the digital twin model and decision support system show
that the desktop-based parametric floatovoltaic synthesis toolset can uniquely characterise the broad and
diverse spectrum of performance benefits of floatovoltaics in a 3E sustainability profile. The model uniquely
predicts important impact aspects of the technology’s land, air and water preservation qualities, quantifying
these impacts in terms of the water, energy, land and food nexus parameters. The proposed GIS model
can quantitatively predict most FPV technology unknowns, thus solving a contemporary real-world prob lem that currently jeopardises floating PV project licensing and approvals. Overall, the posited theoretical
framework, methodology model, and reported results provide an improved understanding of floating PV renewable energy systems and their real-world behaviour. Amidst a rapidly growing international interest in
floatovoltaic solutions, the research advances fresh philosophical ideas with novel theoretical principles that
may have far-reaching implications for developing electronic, photovoltaic performance models worldwide.GeographyPh. D. (Geography
Proceedings of the 2nd Energy Security and Chemical Engineering Congress
Mechanical engineering is a field that is continuously evolving as a profession to provide sustainable design, products and technologies for society. Mechanical engineering products, in conjunction with technological advances in other sectors, contribute to noise, water and air pollution, and the degradation of land and landscape. The rate of production, both energy and products, is increasing at such a rapid rate that natural regeneration can no longer sustain. Emission control is a fast-growing topic for mechanical engineers and others, encompassing the development of machines and processes that produce fewer pollutants as well as new materials and processes that can decrease or eliminate pollution that has already been generated. And, in an increasingly environmentally conscious world, the concept of sustainability is also intrinsically important to the success or failure of any engineering product or processes. Mechanical engineers thus play a central role in applying a truly modern approach for enabling the global transition to green energy and sustainable prac-tices. To address climate change, researchers are progressively looking into a wide range of novel solutions for energy conversion, engine efficiency, alternative fuels, nature-inspired materials, enhanced manufacturing processes and so on. In this context, this book presents part of the proceedings of the Mechanical and Materials track of the 2nd Energy Security and Chemical Engineering Congress (ESChE 2021) as presented by the academics, researchers and postgraduate students. The book provides insights into different aspects of mechanical processes, nanoma-terials and alternate fuels that set the stage for development of sustainable techno-logical solutions. The content of this book will be useful for students, researchers and professionals working in the areas of mechanical engineering, materials, energy technologies, optimization and allied fields
Integrating life cycle assessment in model-based systems engineering
The emergence of smart products has led to the development of an increasing number of multidisciplinary systems. For the successful development of such systems, a holistic approach is necessary, such as model-based systems engineering (MBSE). It is argued that certain product development activities could be integrated and improved with MBSE, one such activity being the assessment of environmental impacts. This article presents a case study on the usage of Life Cycle Assessment (LCA) on a MBSE system model. In the study a technical system is modelled with views according to the MagicGRID approach. The scope and goal of the LCA are defined by using SysML diagrams and elements. Additionally, different system variants are modelled to explore the capability of comparing LCA studies. At the end of the case study, the benefits, limitations, and shortcomings of the integration are discussed
Fast modelling of gas reservoirs using non-intrusive reduced order modelling and machine learning
This work focussed on developing approximate methods for rapidly estimating gas field production performance. Proper orthogonal decomposition (POD) - Radial basis function (RBF) and POD-Autoencoder (AE) Non Intrusive Reduced Order Models (NIROMs) were considered. The accuracy and speed of both NIROMs were evaluated for modelling different aspects of gas field modelling including reservoirs with time-varying and mixed production controls, reservoirs with and without aquifer pressure support, and for wells that were (or not ) shut-in during production lifecycle. These NIROMs were applied to predicting the performance of four gas reservoir models: a homogeneous synthetic model; a heterogeneous gas field with 3 wells and structures similar to the Norne Field; a water coning model in radian grid; and a sector model of a real gas field provided by Woodside Petroleum.
The POD-RBF and POD-AE NIROMs were trained using the simulation solutions from a commercial reservoir simulator (ECLIPSE): grid distributions of pressure and saturations as well as time series production data such as production rates, cumulative productions and pressures. Different cases were run based on typical input parameters usually used in field performance studies. The simulation solutions were then standardised to zero mean and reduced into hyperspace using POD. In most cases, the optimum number of POD basis functions (99.9% energy criterion) of the solutions (training data) were used to reduce the training data into a lower-dimensional hyperspace space. The reduced training data and their corresponding parameter values were combined to form sample and response arrays based on a cause and effect pattern. RBF or AE was then used to interpolate the weighting coefficients that represented the dynamics of the gas reservoir as captured within the reduced training data. These weighting coefficients were used to propagate the prediction of new unseen simulation cases for the duration of predictions. The simulation results from either or both NIROMs was then compared against the simulation solution of the same cases in ECLIPSE.
It was found that the POD-RBF is a better predictive tool for gas field modelling. It is faster, more accurate and consistent than the POD-AE, giving satisfactory predictions with up to 99% accuracy and 2 orders of magnitude speed-up. No single POD-AE is sufficient for predicting different production scenarios, besides, the process of arriving at a suitable POD-AE involves finetuning several hyper-parameters by trial and error, which may be more burdensome for practising petroleum engineers.
The accuracy of NIROM’s prediction of production variable is generally improved by using more than the optimal number of POD-basis functions, while predictions of grid distributed properties are satisfactorily predicted with the optimal number of POD-basis functions. NIROM’s accuracy is dependent on whether the range of parameters of the prediction, their duration and specific production scenarios (such as having mixed production controls or aquifer pressure support) reflect those of the training cases. Overall, the number of training runs, the size of the reservoir model as well as the number of time intervals at which simulation output data is required all affect the speed of training both NIROMs for prediction.
Other contributions of this work include showing that the linear RBF is the most suitable RBF for gas field modelling; developing a novel normalisation approach for time-varying parameters; and applying NIROMs to seasonally varying production scenarios with mixed production controls. This work is the first time that the POD-AE has been developed and evaluated for petroleum field development planning.Open Acces
Structure Preserving Transformations for Practical Model-based Systems Engineering
In this third decade of systems engineering in the twenty-first century, it
is important to develop and demonstrate practical methods to exploit
machine-readable models in the engineering of systems. Substantial investment
has been made in languages and modelling tools for developing models. A key
problem is that system architects and engineers work in a multidisciplinary
environment in which models are not the product of any one individual. This
paper provides preliminary results of a formal approach to specify models and
structure preserving transformations between them that support model
synchronization. This is an important area of research and practice in software
engineering. However, it is limited to synchronization at the code level of
systems. This paper leverages previous research of the authors to define a core
fractal for interpretation of concepts into model specifications and
transformation between models. This fractal is used to extend the concept of
synchronization of models to the system level and is demonstrated through a
practical engineering example for an advanced driver assistance system.Comment: Accepted by the 8th IEEE International Symposium on Systems
Engineering (ISSE 2022), Special Session on Theoretical Foundations of System
Engineering (THEFOSE
Experimentation to Evaluate the Benefits of Model Driven Development
Tesis por compendio[ES] El Desarrollo Dirigido por Modelos, MDD por sus siglas en inglés (Model Driven Development), es un enfoque de ingeniería del software que centra la creación y evolución de productos software en el modelado. Desde hace casi dos décadas, la comunidad científica ha descrito muchas de las ventajas de MDD frente a otros enfoques, sin embargo, su adopción en el entorno industrial es muy poco frecuente.
Con el objetivo de entender por qué MDD no ha reemplazado otros enfoques de ingeniería software, he realizado una investigación empírica a través de tres experimentos controlados. Con el primer experimento pretendo aclarar si los beneficios de MDD frente al Desarrollo centrado en Código, CcD por sus siglas en inglés (Code Centric Development), son fieles a la realidad del desarrollo software actual. En el segundo experimento comparo la valoración que realizan los ingenieros de los modelos que utilizan, con su utilidad para ser utilizados en contextos MDD. En el tercer experimento analizo el desempeño de los profesionales software en tareas de mantenimiento en contextos MDD.
Nuestros resultados confirman los beneficios de MDD frente a otros enfoques, pero también, que la intención de uso de MDD no alcanza valores máximos. Los sujetos subestiman el potencial de los modelos que desarrollan y utilizan en contextos MDD. El problema de adopción parece estar ligado a factores humanos, no a factores técnicos.[CA] El Desenvolupament Dirigit per Models, MDD (Model Driven Development), és un enfocament d'enginyeria del programari que centra la creació i evolució de productes programari en el modelatge. Des de fa quasi dues dècades, la comunitat científica ha descrit moltes dels avantatges de MDD enfront d'altres enfocaments, no obstant això, la seua adopció en l'entorn industrial és molt poc freqüent.
Amb l'objectiu d'entendre per què MDD no ha reemplaçat altres enfocaments d'enginyeria programari, he realitzat una investigació empírica a través de tres experiments controlats. Amb el primer experiment pretenc aclarir si els beneficis de MDD enfront d'altres enfocaments, com el Desenvolupament centrat en Codi, CcD (Code Centric Development), són fidels a la realitat del desenvolupament programari actual. En el segon experiment compare la valoració que realitzen els enginyers dels models que utilitzen, amb la seua utilitat per a ser utilitzats en contextos MDD. En el tercer experiment analitze l'acompliment del professional programari en tasques de manteniment en contextos MDD.
Els nostres resultats confirmen els beneficis de MDD enfront d'altres enfocaments, però també, que la intenció d'ús de MDD no aconsegueix valors màxims. Els subjectes subestimen el potencial dels models que desenvolupen i utilitzen en contextos MDD. El problema d'adopció sembla estar lligat a factors humans, no a factors tècnics.[EN] Model Driven Development (MDD) is a software engineering approach in which the code of a software product is generated and evolutionated from conceptual models that abstractly represents the system. For nearly two decades, the scientific community has described many of the advantages of MDD over other approaches. Despite the benefits of MDD, its use in real practical developments is merely anecdotal.
To understand why MDD has not replaced other software engineering approaches, I have conducted an empirical investigation through three controlled experiments. The first experiment aims to clarify whether the benefits of MDD compared to code-centric development (CcD) match the reality of development in real environments. In the second experiment, I compare engineers' assessment of the models they develop with the usefulness of these models to be used in MDD contexts. In the third experiment, I analyze the performance of software professionals in maintenance tasks in MDD contexts.
Our results confirm the benefits of MDD over other approaches; however, the intention to use MDD does not reach maximum values. Subjects underestimate the potential of the models they develop and use in MDD contexts. The adoption problem seems to be linked to human factors, not to technical factors.Domingo Montes, MÁ. (2022). Experimentation to Evaluate the Benefits of Model Driven Development [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185748Compendi
European Privacy by Design [védés előtt]
Three competing forces are shaping the concept of European Privacy by Design (PbD): laws and regulations, business goals and architecture designs. These forces carry their own influence in terms of ethics, economics, and technology.
In this research we undertook the journey to understand the concept of European PbD. We examined its nature, application, and enforcement. We concluded that the European PbD is under-researched in two aspects: at organizational level (compared to the individual level); and mainly in the way it is enforced by authorities. We had high hopes especially with regards to the latter, and eager to bring significant scientific contribution on this field. We were interested to learn if data protection authorities are having such impacts looking at European PbD, that can pioneer new approaches to privacy preservation. This is why we elaborated on possible ways to measure their activity, in a manner that both legal and non-legal experts can understand our work.
We promised a response to the research question can the enforcement of European PbD be measured and if yes, what are possible ways to do so? We conducted data analytics on quantitative and qualitative data to answer this question the best way possible. Our response is a moderate yes, the enforcement of PbD can be measured. Although, at this point, we need to settle with only good-enough ways of measure and not dwell into choosing the most optimal or best ways.
One reason for this is that enforcement of PbD cases are highly customized and specific to their own circumstances. We have shown this while creating models to predict the amount of administrative fines for infringement of GDPR. Clustering these cases was a daunting task.
Second reason for not delivering what could be the best way of measure is lack of data availability in Europe. This problem has its roots in the philosophical stance that the European legislator is taking on the topic of data collection within the EU. Lawmakers in Europe certainly dislike programs that collect gigantic amounts of personal data from EU citizens.
Third reason is a causal link between the inconsistent approach between the data protection authorities’ practices. This is due to the different levels of competencies, reporting structures, personnel numbers, and experience in the work of data protection authorities.
Looking beyond the above limitations, there are certainly ways to measure the enforcement of European PbD. Our measurements helped us formulate the following statements:
a. The European PbD operates in ‘data saver’ mode: we argue that analogous to the data saving mode on mobile phones, where most applications and services get background data only via Wi-Fi connection, in Europe data collection and data processing is kept to minimal. Therefore, we argue that European PbD is in essence about data minimization. Our conviction that this concept is more oriented towards data security have been partially refuted.
b. The European PbD is platform independent: we elaborated in the thesis on various infrastructures and convergent technologies that found compatibility with the PbD principles. We consider that the indeed the concept is evolutionary and technology –neutral.
c. The European PbD is a tool obligation: we argue that the authorities are looking at PbD as a tool utilization obligation. In a simple language, companies should first perform a privacy impact assessment in order to find out which tools are supporting their data processing activities and then implement these, as mandated PbD.
d. The European PbD is highly territorial: we reached the conclusion that enforcement of PbD is highly dependent on geographical indicators (i.e. countries and counties). The different level of privacy protection cultures are still present in Europe. On a particular level, what is commonly true across all countries is that European PbD mandates strong EU data sovereignty
APPLICATIONS OF GRAPH THEORY FOR REUSE OF MODEL BASED SYSTEMS ENGINEERING DESIGN DATA
This dissertation contributes to systems engineering (SE) by introducing and demonstrating a novel graph-based design repository (GBDR) tool. GBDR enables engineers to leverage system design information from a heterogenous set of system models created using multiple model based systems engineering (MBSE) software tools as an integrated body of knowledge. Specifically, the research provides a set of approaches that allow the use of system models described in Systems Modeling Language and Lifecycle Modeling Language as an integrated body of design information. The coalesced body of system design information serves to support concept ideation and analysis within SE. The research accomplishes this by using a graph database to store system model information imported from digital artifacts created by MBSE tools and applying principles from graph theory and semantic web technologies to identify likely connections and equivalent concepts across system models, modeling languages, and metamodels. The research demonstrates that the presented tool can import, store, synthesize, search, display, distribute, and export information from multiple MBSE tools. As a practical demonstration, feasible subsystem design alternatives for a small unmanned aircraft system government reference architecture are identified from within a set of existing system models.OSD CAPECivilian, Office of the Secretary of DefenseApproved for public release. Distribution is unlimited
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