932 research outputs found
Pristup specifikaciji i generisanju proizvodnih procesa zasnovan na inženjerstvu vođenom modelima
In this thesis, we present an approach to the production process specification and generation based on the model-driven paradigm, with the goal to increase the flexibility of factories and respond to the challenges that emerged in the era of Industry 4.0 more efficiently. To formally specify production processes and their variations in the Industry 4.0 environment, we created a novel domain-specific modeling language, whose models are machine-readable. The created language can be used to model production processes that can be independent of any production system, enabling process models to be used in different production systems, and process models used for the specific production system. To automatically transform production process models dependent on the specific production system into instructions that are to be executed by production system resources, we created an instruction generator. Also, we created generators for different manufacturing documentation, which automatically transform production process models into manufacturing documents of different types. The proposed approach, domain-specific modeling language, and software solution contribute to introducing factories into the digital transformation process. As factories must rapidly adapt to new products and their variations in the era of Industry 4.0, production must be dynamically led and instructions must be automatically sent to factory resources, depending on products that are to be created on the shop floor. The proposed approach contributes to the creation of such a dynamic environment in contemporary factories, as it allows to automatically generate instructions from process models and send them to resources for execution. Additionally, as there are numerous different products and their variations, keeping the required manufacturing documentation up to date becomes challenging, which can be done automatically by using the proposed approach and thus significantly lower process designers' time.У овој дисертацији представљен је приступ спецификацији и генерисању производних процеса заснован на инжењерству вођеном моделима, у циљу повећања флексибилности постројења у фабрикама и ефикаснијег разрешавања изазова који се појављују у ери Индустрије 4.0. За потребе формалне спецификације производних процеса и њихових варијација у амбијенту Индустрије 4.0, креиран је нови наменски језик, чије моделе рачунар може да обради на аутоматизован начин. Креирани језик има могућност моделовања производних процеса који могу бити независни од производних система и тиме употребљени у различитим постројењима или фабрикама, али и производних процеса који су специфични за одређени систем. Како би моделе производних процеса зависних од конкретног производног система било могуће на аутоматизован начин трансформисати у инструкције које ресурси производног система извршавају, креиран је генератор инструкција. Такође су креирани и генератори техничке документације, који на аутоматизован начин трансформишу моделе производних процеса у документе различитих типова. Употребом предложеног приступа, наменског језика и софтверског решења доприноси се увођењу фабрика у процес дигиталне трансформације. Како фабрике у ери Индустрије 4.0 морају брзо да се прилагоде новим производима и њиховим варијацијама, неопходно је динамички водити производњу и на аутоматизован начин слати инструкције ресурсима у фабрици, у зависности од производа који се креирају у конкретном постројењу. Тиме што је у предложеном приступу могуће из модела процеса аутоматизовано генерисати инструкције и послати их ресурсима, доприноси се креирању једног динамичког окружења у савременим фабрикама. Додатно, услед великог броја различитих производа и њихових варијација, постаје изазовно одржавати неопходну техничку документацију, што је у предложеном приступу могуће урадити на аутоматизован начин и тиме значајно уштедети време пројектаната процеса.U ovoj disertaciji predstavljen je pristup specifikaciji i generisanju proizvodnih procesa zasnovan na inženjerstvu vođenom modelima, u cilju povećanja fleksibilnosti postrojenja u fabrikama i efikasnijeg razrešavanja izazova koji se pojavljuju u eri Industrije 4.0. Za potrebe formalne specifikacije proizvodnih procesa i njihovih varijacija u ambijentu Industrije 4.0, kreiran je novi namenski jezik, čije modele računar može da obradi na automatizovan način. Kreirani jezik ima mogućnost modelovanja proizvodnih procesa koji mogu biti nezavisni od proizvodnih sistema i time upotrebljeni u različitim postrojenjima ili fabrikama, ali i proizvodnih procesa koji su specifični za određeni sistem. Kako bi modele proizvodnih procesa zavisnih od konkretnog proizvodnog sistema bilo moguće na automatizovan način transformisati u instrukcije koje resursi proizvodnog sistema izvršavaju, kreiran je generator instrukcija. Takođe su kreirani i generatori tehničke dokumentacije, koji na automatizovan način transformišu modele proizvodnih procesa u dokumente različitih tipova. Upotrebom predloženog pristupa, namenskog jezika i softverskog rešenja doprinosi se uvođenju fabrika u proces digitalne transformacije. Kako fabrike u eri Industrije 4.0 moraju brzo da se prilagode novim proizvodima i njihovim varijacijama, neophodno je dinamički voditi proizvodnju i na automatizovan način slati instrukcije resursima u fabrici, u zavisnosti od proizvoda koji se kreiraju u konkretnom postrojenju. Time što je u predloženom pristupu moguće iz modela procesa automatizovano generisati instrukcije i poslati ih resursima, doprinosi se kreiranju jednog dinamičkog okruženja u savremenim fabrikama. Dodatno, usled velikog broja različitih proizvoda i njihovih varijacija, postaje izazovno održavati neophodnu tehničku dokumentaciju, što je u predloženom pristupu moguće uraditi na automatizovan način i time značajno uštedeti vreme projektanata procesa
Chatbots for Modelling, Modelling of Chatbots
Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Escuela Politécnica Superior, Departamento de Ingeniería Informática. Fecha de Lectura: 28-03-202
The effectiveness of computer-based information systems: definition and measurement
Determining and enhancing the effectiveness of computer-based information systems (1/S) in organisations remains a top priority of managers. This study shows that the essential nature and role of 1/S is changing and that classic views of 1/S effectiveness have become increasingly inappropriate. Drawing on the organisational effectiveness literature, it is argued that user perceptions provide a practical alternative and a conceptually sound basis for defining and measuring 1/S effectiveness. A popular measure - User Information Satisfaction - is examined and empirical studies using this measure are critiqued. This reveal limited theoretical grounding or convergence but a growing emphasis on behavioural theory. Based on prior empirical work by the author and expectancy and motivation theory, a model of 1/S behaviours is offered. The model suggests that fit between the needs of the organisation and the capability of 1/S to satisfy these needs is essential to achieving 1/S effectiveness. Several hypotheses are formulated. The development and validation of a particular measurement instrument is traced. The instrument addresses 37 facets of the overall information systems function and respondents complete perceptual scales tapping the relative importance of these facets and how well each is performed. The instrument is used in a field survey of 1025 managers and 1/S staff in eleven large organisations. Attitudes towards 1/S are found to correlate with perceptions of fit between organisational needs and 1/S capabilities. The survey is complemented by management interviews, document analysis and an assessment of the dynamics of the relevant 1/S groups. Cultural and other features associated with perceived 1/S success are found. It is concluded that perceptions of organisational members are central to the meaning of information systems effectiveness, but that the user information satisfaction construct and purely attitudinal measures are inadequate. Based on the notion of fit, a new definition of 1/S effectiveness is proposed. Guidelines for measurement are presented and it is argued that the instrument used in this study is a satisfactory tool. Specific recommendations for management are made and rich opportunities for future research are identified
An uncertainty prediction approach for active learning - application to earth observation
Mapping land cover and land usage dynamics are crucial in remote sensing since farmers
are encouraged to either intensify or extend crop use due to the ongoing rise in the world’s
population. A major issue in this area is interpreting and classifying a scene captured in
high-resolution satellite imagery. Several methods have been put forth, including neural
networks which generate data-dependent models (i.e. model is biased toward data) and
static rule-based approaches with thresholds which are limited in terms of diversity(i.e.
model lacks diversity in terms of rules). However, the problem of having a machine learning
model that, given a large amount of training data, can classify multiple classes over different
geographic Sentinel-2 imagery that out scales existing approaches remains open.
On the other hand, supervised machine learning has evolved into an essential part of many
areas due to the increasing number of labeled datasets. Examples include creating classifiers
for applications that recognize images and voices, anticipate traffic, propose products, act
as a virtual personal assistant and detect online fraud, among many more. Since these
classifiers are highly dependent from the training datasets, without human interaction or
accurate labels, the performance of these generated classifiers with unseen observations
is uncertain. Thus, researchers attempted to evaluate a number of independent models
using a statistical distance. However, the problem of, given a train-test split and classifiers
modeled over the train set, identifying a prediction error using the relation between train
and test sets remains open.
Moreover, while some training data is essential for supervised machine learning, what
happens if there is insufficient labeled data? After all, assigning labels to unlabeled datasets
is a time-consuming process that may need significant expert human involvement. When
there aren’t enough expert manual labels accessible for the vast amount of openly available
data, active learning becomes crucial. However, given a large amount of training and
unlabeled datasets, having an active learning model that can reduce the training cost of
the classifier and at the same time assist in labeling new data points remains an open
problem.
From the experimental approaches and findings, the main research contributions, which
concentrate on the issue of optical satellite image scene classification include: building
labeled Sentinel-2 datasets with surface reflectance values; proposal of machine learning
models for pixel-based image scene classification; proposal of a statistical distance based
Evidence Function Model (EFM) to detect ML models misclassification; and proposal of
a generalised sampling approach for active learning that, together with the EFM enables
a way of determining the most informative examples.
Firstly, using a manually annotated Sentinel-2 dataset, Machine Learning (ML) models
for scene classification were developed and their performance was compared to Sen2Cor the reference package from the European Space Agency – a micro-F1 value of 84%
was attained by the ML model, which is a significant improvement over the corresponding
Sen2Cor performance of 59%. Secondly, to quantify the misclassification of the ML models,
the Mahalanobis distance-based EFM was devised. This model achieved, for the labeled
Sentinel-2 dataset, a micro-F1 of 67.89% for misclassification detection. Lastly, EFM was
engineered as a sampling strategy for active learning leading to an approach that attains
the same level of accuracy with only 0.02% of the total training samples when compared
to a classifier trained with the full training set.
With the help of the above-mentioned research contributions, we were able to provide
an open-source Sentinel-2 image scene classification package which consists of ready-touse
Python scripts and a ML model that classifies Sentinel-2 L1C images generating a
20m-resolution RGB image with the six studied classes (Cloud, Cirrus, Shadow, Snow,
Water, and Other) giving academics a straightforward method for rapidly and effectively
classifying Sentinel-2 scene images. Additionally, an active learning approach that uses, as
sampling strategy, the observed prediction uncertainty given by EFM, will allow labeling
only the most informative points to be used as input to build classifiers; Sumário:
Uma Abordagem de Previsão de Incerteza para
Aprendizagem Ativa – Aplicação à Observação da Terra
O mapeamento da cobertura do solo e a dinâmica da utilização do solo são cruciais na
deteção remota uma vez que os agricultores são incentivados a intensificar ou estender as
culturas devido ao aumento contínuo da população mundial. Uma questão importante
nesta área é interpretar e classificar cenas capturadas em imagens de satélite de alta resolução.
Várias aproximações têm sido propostas incluindo a utilização de redes neuronais
que produzem modelos dependentes dos dados (ou seja, o modelo é tendencioso em relação
aos dados) e aproximações baseadas em regras que apresentam restrições de diversidade
(ou seja, o modelo carece de diversidade em termos de regras). No entanto, a criação de
um modelo de aprendizagem automática que, dada uma uma grande quantidade de dados
de treino, é capaz de classificar, com desempenho superior, as imagens do Sentinel-2 em
diferentes áreas geográficas permanece um problema em aberto.
Por outro lado, têm sido utilizadas técnicas de aprendizagem supervisionada na resolução
de problemas nas mais diversas áreas de devido à proliferação de conjuntos de dados etiquetados.
Exemplos disto incluem classificadores para aplicações que reconhecem imagem
e voz, antecipam tráfego, propõem produtos, atuam como assistentes pessoais virtuais e
detetam fraudes online, entre muitos outros. Uma vez que estes classificadores são fortemente
dependente do conjunto de dados de treino, sem interação humana ou etiquetas
precisas, o seu desempenho sobre novos dados é incerta. Neste sentido existem propostas
para avaliar modelos independentes usando uma distância estatística. No entanto, o problema
de, dada uma divisão de treino-teste e um classificador, identificar o erro de previsão
usando a relação entre aqueles conjuntos, permanece aberto.
Mais ainda, embora alguns dados de treino sejam essenciais para a aprendizagem supervisionada,
o que acontece quando a quantidade de dados etiquetados é insuficiente? Afinal,
atribuir etiquetas é um processo demorado e que exige perícia, o que se traduz num envolvimento
humano significativo. Quando a quantidade de dados etiquetados manualmente por
peritos é insuficiente a aprendizagem ativa torna-se crucial. No entanto, dada uma grande
quantidade dados de treino não etiquetados, ter um modelo de aprendizagem ativa que
reduz o custo de treino do classificador e, ao mesmo tempo, auxilia a etiquetagem de novas
observações permanece um problema em aberto.
A partir das abordagens e estudos experimentais, as principais contribuições deste trabalho,
que se concentra na classificação de cenas de imagens de satélite óptico incluem:
criação de conjuntos de dados Sentinel-2 etiquetados, com valores de refletância de superfície;
proposta de modelos de aprendizagem automática baseados em pixels para classificação de cenas de imagens de satétite; proposta de um Modelo de Função de Evidência (EFM)
baseado numa distância estatística para detetar erros de classificação de modelos de aprendizagem;
e proposta de uma abordagem de amostragem generalizada para aprendizagem
ativa que, em conjunto com o EFM, possibilita uma forma de determinar os exemplos mais
informativos.
Em primeiro lugar, usando um conjunto de dados Sentinel-2 etiquetado manualmente,
foram desenvolvidos modelos de Aprendizagem Automática (AA) para classificação de cenas
e seu desempenho foi comparado com o do Sen2Cor – o produto de referência da
Agência Espacial Europeia – tendo sido alcançado um valor de micro-F1 de 84% pelo classificador,
o que representa uma melhoria significativa em relação ao desempenho Sen2Cor
correspondente, de 59%. Em segundo lugar, para quantificar o erro de classificação dos
modelos de AA, foi concebido o Modelo de Função de Evidência baseado na distância de
Mahalanobis. Este modelo conseguiu, para o conjunto de dados etiquetado do Sentinel-2
um micro-F1 de 67,89% na deteção de classificação incorreta. Por fim, o EFM foi utilizado
como uma estratégia de amostragem para a aprendizagem ativa, uma abordagem
que permitiu atingir o mesmo nível de desempenho com apenas 0,02% do total de exemplos
de treino quando comparado com um classificador treinado com o conjunto de treino
completo.
Com a ajuda das contribuições acima mencionadas, foi possível desenvolver um pacote
de código aberto para classificação de cenas de imagens Sentinel-2 que, utilizando num
conjunto de scripts Python, um modelo de classificação, e uma imagem Sentinel-2 L1C,
gera a imagem RGB correspondente (com resolução de 20m) com as seis classes estudadas
(Cloud, Cirrus, Shadow, Snow, Water e Other), disponibilizando à academia um método
direto para a classificação de cenas de imagens do Sentinel-2 rápida e eficaz. Além disso, a
abordagem de aprendizagem ativa que usa, como estratégia de amostragem, a deteção de
classificacão incorreta dada pelo EFM, permite etiquetar apenas os pontos mais informativos
a serem usados como entrada na construção de classificadores
General Course Catalog [2022/23 academic year]
General Course Catalog, 2022/23 academic yearhttps://repository.stcloudstate.edu/undergencat/1134/thumbnail.jp
Re-Discovering & Re-Conceptualising Local Area Plans: A Qualitative Investigation in Guiding Spatial Sustainability in Maitland, Cape Town
Cities and their sub-units are increasingly conceived as being dynamic, relational, and unbounded. Due to these attributes, they are recognised as a key means of driving sustainability and sustainable urban development (which is best understood as the entwined requirements for progress towards lasting wellbeing). In response to this, the global policy document the New Urban Agenda Illustrated introduced a fourth dimension to sustainable urban development: spatial sustainability, wherein guiding the physical form of urban environments towards specific spatial conditions can enhance social, economic, and environmental value and wellbeing and, in so doing, arrive at equity. The document recommends the use of local area plans to guide urban development toward spatial sustainability. However, South Africa's local area plans are currently not conceptualised to guide spatial sustainability which, as a recent global concept, has yet to be rigorously researched in specific contexts. Moreover, local area plans are generally under-explored and under-utilised in South African planning theory and policy, where the emphasis is on large-scale strategic spatial plans and spatial development frameworks. In response to this, the research aims to 1) establish whether South Africa's planning system requires local area plans and, if so, to clarify their contribution, and 2) to enrich the interpretation of spatial sustainability, with the view to 3) exploring how planners might re-discover and re-conceptualise local area plans to guide spatial sustainability. The research aims were achieved through the qualitative research approach that methodologically made use of a case study in Maitland, Cape Town. Data was collected and analysed through various techniques and against a conceptual framework derived from a literature review. The study employed design-orientated inquiry in which an initial local area plan proposal was presented to a focus group and – based on their feedback – undetected facets of analysis were further explored and the local area plan proposal was redrafted. The enriched interpretation of spatial sustainability recognises that space that seeks to achieve equity comprises relations and processes as much as the substantive features of physical form. To this end, the research suggests that it is necessary to appreciate the context, structure, and dynamics of place (the product of planned space), which is best understood through analysing the activity, psychology, and physicality of place. The results of this analysis in Maitland are threefold. Firstly, the analysis confirms that local area plans are a crucial component of South Africa's planning system when situated in areas of strategic importance. Secondly, Maitland is revealed to be a multifaceted port-of-entry neighbourhood where relations and practices extend beyond the area's boundaries. Thirdly, the results suggest that a local area plan re-conceptualised to guide spatial sustainability should be viewed as both a process and a product. In other words, local area planning requires two responses: it needs to produce a material local area plan (the plan as a noun), and the method of achieving that plan needs to foster the conditions for diverse current and future involvement in the planning process (planning as a verb). Based on these significant findings and using Maitland as a point of reference, the research proposes recommendations for preparing for, producing, and sustaining a local area plan in areas of strategic importance. Re-discovered and re-conceptualised in this way, local area plans are an essential means of achieving equity and lasting wellbeing in complex contemporary contexts, which is the fundamental objective of spatial sustainability
The effectiveness of computer-based information systems : definition and measurement
Determining and enhancing the effectiveness of computer-based information systems (1/S) in organisations remains a top priority of managers. This study shows that the essential nature and role of 1/S is changing and that classic views of 1/S effectiveness have become increasingly inappropriate. Drawing on the organisational effectiveness literature, it is argued that user perceptions provide a practical alternative and a conceptually sound basis for defining and measuring 1/S effectiveness. A popular measure - User Information Satisfaction - is examined and empirical studies using this measure are critiqued. This reveal limited theoretical grounding or convergence but a growing emphasis on behavioural theory. Based on prior empirical work by the author and expectancy and motivation theory, a model of 1/S behaviours is offered. The model suggests that fit between the needs of the organisation and the capability of 1/S to satisfy these needs is essential to achieving 1/S effectiveness. Several hypotheses are formulated. The development and validation of a particular measurement instrument is traced. The instrument addresses 37 facets of the overall information systems function and respondents complete perceptual scales tapping the relative importance of these facets and how well each is performed. The instrument is used in a field survey of 1025 managers and 1/S staff in eleven large organisations. Attitudes towards 1/S are found to correlate with perceptions of fit between organisational needs and 1/S capabilities. The survey is complemented by management interviews, document analysis and an assessment of the dynamics of the relevant 1/S groups. Cultural and other features associated with perceived 1/S success are found. It is concluded that perceptions of organisational members are central to the meaning of information systems effectiveness, but that the user information satisfaction construct and purely attitudinal measures are inadequate. Based on the notion of fit, a new definition of 1/S effectiveness is proposed. Guidelines for measurement are presented and it is argued that the instrument used in this study is a satisfactory tool. Specific recommendations for management are made and rich opportunities for future research are identified
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