8,275 research outputs found
Corporate Social Responsibility: the institutionalization of ESG
Understanding the impact of Corporate Social Responsibility (CSR) on firm performance as it relates to industries reliant on technological innovation is a complex and perpetually evolving challenge. To thoroughly investigate this topic, this dissertation will adopt an economics-based structure to address three primary hypotheses. This structure allows for each hypothesis to essentially be a standalone empirical paper, unified by an overall analysis of the nature of impact that ESG has on firm performance. The first hypothesis explores the evolution of CSR to the modern quantified iteration of ESG has led to the institutionalization and standardization of the CSR concept. The second hypothesis fills gaps in existing literature testing the relationship between firm performance and ESG by finding that the relationship is significantly positive in long-term, strategic metrics (ROA and ROIC) and that there is no correlation in short-term metrics (ROE and ROS). Finally, the third hypothesis states that if a firm has a long-term strategic ESG plan, as proxied by the publication of CSR reports, then it is more resilience to damage from controversies. This is supported by the finding that pro-ESG firms consistently fared better than their counterparts in both financial and ESG performance, even in the event of a controversy. However, firms with consistent reporting are also held to a higher standard than their nonreporting peers, suggesting a higher risk and higher reward dynamic. These findings support the theory of good management, in that long-term strategic planning is both immediately economically beneficial and serves as a means of risk management and social impact mitigation. Overall, this contributes to the literature by fillings gaps in the nature of impact that ESG has on firm performance, particularly from a management perspective
Examples of works to practice staccato technique in clarinet instrument
Klarnetin staccato tekniğini güçlendirme aşamaları eser çalışmalarıyla uygulanmıştır. Staccato
geçişlerini hızlandıracak ritim ve nüans çalışmalarına yer verilmiştir. Çalışmanın en önemli amacı
sadece staccato çalışması değil parmak-dilin eş zamanlı uyumunun hassasiyeti üzerinde de
durulmasıdır. Staccato çalışmalarını daha verimli hale getirmek için eser çalışmasının içinde etüt
çalışmasına da yer verilmiştir. Çalışmaların üzerinde titizlikle durulması staccato çalışmasının ilham
verici etkisi ile müzikal kimliğe yeni bir boyut kazandırmıştır. Sekiz özgün eser çalışmasının her
aşaması anlatılmıştır. Her aşamanın bir sonraki performans ve tekniği güçlendirmesi esas alınmıştır.
Bu çalışmada staccato tekniğinin hangi alanlarda kullanıldığı, nasıl sonuçlar elde edildiği bilgisine
yer verilmiştir. Notaların parmak ve dil uyumu ile nasıl şekilleneceği ve nasıl bir çalışma disiplini
içinde gerçekleşeceği planlanmıştır. Kamış-nota-diyafram-parmak-dil-nüans ve disiplin
kavramlarının staccato tekniğinde ayrılmaz bir bütün olduğu saptanmıştır. Araştırmada literatür
taraması yapılarak staccato ile ilgili çalışmalar taranmıştır. Tarama sonucunda klarnet tekniğin de
kullanılan staccato eser çalışmasının az olduğu tespit edilmiştir. Metot taramasında da etüt
çalışmasının daha çok olduğu saptanmıştır. Böylelikle klarnetin staccato tekniğini hızlandırma ve
güçlendirme çalışmaları sunulmuştur. Staccato etüt çalışmaları yapılırken, araya eser çalışmasının
girmesi beyni rahatlattığı ve istekliliği daha arttırdığı gözlemlenmiştir. Staccato çalışmasını yaparken
doğru bir kamış seçimi üzerinde de durulmuştur. Staccato tekniğini doğru çalışmak için doğru bir
kamışın dil hızını arttırdığı saptanmıştır. Doğru bir kamış seçimi kamıştan rahat ses çıkmasına
bağlıdır. Kamış, dil atma gücünü vermiyorsa daha doğru bir kamış seçiminin yapılması gerekliliği
vurgulanmıştır. Staccato çalışmalarında baştan sona bir eseri yorumlamak zor olabilir. Bu açıdan
çalışma, verilen müzikal nüanslara uymanın, dil atış performansını rahatlattığını ortaya koymuştur.
Gelecek nesillere edinilen bilgi ve birikimlerin aktarılması ve geliştirici olması teşvik edilmiştir.
Çıkacak eserlerin nasıl çözüleceği, staccato tekniğinin nasıl üstesinden gelinebileceği anlatılmıştır.
Staccato tekniğinin daha kısa sürede çözüme kavuşturulması amaç edinilmiştir. Parmakların
yerlerini öğrettiğimiz kadar belleğimize de çalışmaların kaydedilmesi önemlidir. Gösterilen azmin ve
sabrın sonucu olarak ortaya çıkan yapıt başarıyı daha da yukarı seviyelere çıkaracaktır
Full Resolution Deconvolution of Complex Faraday Spectra
Polarized synchrotron emission from multiple Faraday depths can be separated
by calculating the complex Fourier transform of the Stokes' parameters as a
function of the wavelength squared, known as Faraday Synthesis. As commonly
implemented, the transform introduces an additional term , which
broadens the real and imaginary spectra, but not the amplitude spectrum. We use
idealized tests to investigate whether additional information can be recovered
with a clean process restoring beam set to the narrower width of the peak in
the real ``full" resolution spectrum with . We find that the
choice makes no difference, except for the use of a smaller
restoring beam. With this smaller beam, the accuracy and phase stability are
unchanged for single Faraday components. However, using the smaller restoring
beam for multiple Faraday components we find a) better discrimination of the
components, b) significant reductions in blending of structures in tomography
images, and c) reduction of spurious features in the Faraday spectra and
tomography maps. We also discuss the limited accuracy of information on scales
comparable to the width of the amplitude spectrum peak, and note a clean-bias,
reducing the recovered amplitudes. We present examples using MeerKAT L-band
data. We also revisit the maximum width in Faraday depth to which surveys are
sensitive, and introduce the variable , the width for which the power
drops by a factor of 2. We find that most surveys cannot resolve continuous
Faraday distributions unless the narrower full restoring beam is used.Comment: 17 pages, 23 figures, accepted for publication in MNRAS, 4 April,
202
A Decision Support System for Economic Viability and Environmental Impact Assessment of Vertical Farms
Vertical farming (VF) is the practice of growing crops or animals using the vertical dimension via multi-tier racks or vertically inclined surfaces. In this thesis, I focus on the emerging industry of plant-specific VF. Vertical plant farming (VPF) is a promising and relatively novel practice that can be conducted in buildings with environmental control and artificial lighting. However, the nascent sector has experienced challenges in economic viability, standardisation, and environmental sustainability. Practitioners and academics call for a comprehensive financial analysis of VPF, but efforts are stifled by a lack of valid and available data.
A review of economic estimation and horticultural software identifies a need for a decision support system (DSS) that facilitates risk-empowered business planning for vertical farmers. This thesis proposes an open-source DSS framework to evaluate business sustainability through financial risk and environmental impact assessments. Data from the literature, alongside lessons learned from industry practitioners, would be centralised in the proposed DSS using imprecise data techniques. These techniques have been applied in engineering but are seldom used in financial forecasting. This could benefit complex sectors which only have scarce data to predict business viability.
To begin the execution of the DSS framework, VPF practitioners were interviewed using a mixed-methods approach. Learnings from over 19 shuttered and operational VPF projects provide insights into the barriers inhibiting scalability and identifying risks to form a risk taxonomy. Labour was the most commonly reported top challenge. Therefore, research was conducted to explore lean principles to improve productivity.
A probabilistic model representing a spectrum of variables and their associated uncertainty was built according to the DSS framework to evaluate the financial risk for VF projects. This enabled flexible computation without precise production or financial data to improve economic estimation accuracy. The model assessed two VPF cases (one in the UK and another in Japan), demonstrating the first risk and uncertainty quantification of VPF business models in the literature. The results highlighted measures to improve economic viability and the viability of the UK and Japan case.
The environmental impact assessment model was developed, allowing VPF operators to evaluate their carbon footprint compared to traditional agriculture using life-cycle assessment. I explore strategies for net-zero carbon production through sensitivity analysis. Renewable energies, especially solar, geothermal, and tidal power, show promise for reducing the carbon emissions of indoor VPF. Results show that renewably-powered VPF can reduce carbon emissions compared to field-based agriculture when considering the land-use change.
The drivers for DSS adoption have been researched, showing a pathway of compliance and design thinking to overcome the ‘problem of implementation’ and enable commercialisation. Further work is suggested to standardise VF equipment, collect benchmarking data, and characterise risks. This work will reduce risk and uncertainty and accelerate the sector’s emergence
Estudo da remodelagem reversa miocárdica através da análise proteómica do miocárdio e do líquido pericárdico
Valve replacement remains as the standard therapeutic option for aortic
stenosis patients, aiming at abolishing pressure overload and triggering
myocardial reverse remodeling. However, despite the instant hemodynamic
benefit, not all patients show complete regression of myocardial hypertrophy,
being at higher risk for adverse outcomes, such as heart failure. The current
comprehension of the biological mechanisms underlying an incomplete reverse
remodeling is far from complete. Furthermore, definitive prognostic tools and
ancillary therapies to improve the outcome of the patients undergoing valve
replacement are missing. To help abridge these gaps, a combined myocardial
(phospho)proteomics and pericardial fluid proteomics approach was followed,
taking advantage of human biopsies and pericardial fluid collected during
surgery and whose origin anticipated a wealth of molecular information
contained therein.
From over 1800 and 750 proteins identified, respectively, in the myocardium
and in the pericardial fluid of aortic stenosis patients, a total of 90 dysregulated
proteins were detected. Gene annotation and pathway enrichment analyses,
together with discriminant analysis, are compatible with a scenario of increased
pro-hypertrophic gene expression and protein synthesis, defective ubiquitinproteasome system activity, proclivity to cell death (potentially fed by
complement activity and other extrinsic factors, such as death receptor
activators), acute-phase response, immune system activation and fibrosis.
Specific validation of some targets through immunoblot techniques and
correlation with clinical data pointed to complement C3 β chain, Muscle Ring
Finger protein 1 (MuRF1) and the dual-specificity Tyr-phosphorylation
regulated kinase 1A (DYRK1A) as potential markers of an incomplete
response. In addition, kinase prediction from phosphoproteome data suggests
that the modulation of casein kinase 2, the family of IκB kinases, glycogen
synthase kinase 3 and DYRK1A may help improve the outcome of patients
undergoing valve replacement. Particularly, functional studies with DYRK1A+/-
cardiomyocytes show that this kinase may be an important target to treat
cardiac dysfunction, provided that mutant cells presented a different response
to stretch and reduced ability to develop force (active tension).
This study opens many avenues in post-aortic valve replacement reverse
remodeling research. In the future, gain-of-function and/or loss-of-function
studies with isolated cardiomyocytes or with animal models of aortic bandingdebanding will help disclose the efficacy of targeting the surrogate therapeutic
targets. Besides, clinical studies in larger cohorts will bring definitive proof of
complement C3, MuRF1 and DYRK1A prognostic value.A substituição da válvula aórtica continua a ser a opção terapêutica de
referência para doentes com estenose aórtica e visa a eliminação da
sobrecarga de pressão, desencadeando a remodelagem reversa miocárdica.
Contudo, apesar do benefício hemodinâmico imediato, nem todos os pacientes
apresentam regressão completa da hipertrofia do miocárdio, ficando com maior
risco de eventos adversos, como a insuficiência cardíaca. Atualmente, os
mecanismos biológicos subjacentes a uma remodelagem reversa incompleta
ainda não são claros. Além disso, não dispomos de ferramentas de
prognóstico definitivos nem de terapias auxiliares para melhorar a condição
dos pacientes indicados para substituição da válvula. Para ajudar a resolver
estas lacunas, uma abordagem combinada de (fosfo)proteómica e proteómica
para a caracterização, respetivamente, do miocárdio e do líquido pericárdico
foi seguida, tomando partido de biópsias e líquidos pericárdicos recolhidos em
ambiente cirúrgico.
Das mais de 1800 e 750 proteínas identificadas, respetivamente, no miocárdio
e no líquido pericárdico dos pacientes com estenose aórtica, um total de 90
proteínas desreguladas foram detetadas. As análises de anotação de genes,
de enriquecimento de vias celulares e discriminativa corroboram um cenário de
aumento da expressão de genes pro-hipertróficos e de síntese proteica, um
sistema ubiquitina-proteassoma ineficiente, uma tendência para morte celular
(potencialmente acelerada pela atividade do complemento e por outros fatores
extrínsecos que ativam death receptors), com ativação da resposta de fase
aguda e do sistema imune, assim como da fibrose.
A validação de alguns alvos específicos através de immunoblot e correlação
com dados clínicos apontou para a cadeia β do complemento C3, a Muscle
Ring Finger protein 1 (MuRF1) e a dual-specificity Tyr-phosphoylation
regulated kinase 1A (DYRK1A) como potenciais marcadores de uma resposta
incompleta. Por outro lado, a predição de cinases a partir do fosfoproteoma,
sugere que a modulação da caseína cinase 2, a família de cinases do IκB, a
glicogénio sintase cinase 3 e da DYRK1A pode ajudar a melhorar a condição
dos pacientes indicados para intervenção. Em particular, a avaliação funcional
de cardiomiócitos DYRK1A+/- mostraram que esta cinase pode ser um alvo
importante para tratar a disfunção cardíaca, uma vez que os miócitos mutantes
responderam de forma diferente ao estiramento e mostraram uma menor
capacidade para desenvolver força (tensão ativa).
Este estudo levanta várias hipóteses na investigação da remodelagem reversa.
No futuro, estudos de ganho e/ou perda de função realizados em
cardiomiócitos isolados ou em modelos animais de banding-debanding da
aorta ajudarão a testar a eficácia de modular os potenciais alvos terapêuticos
encontrados. Além disso, estudos clínicos em coortes de maior dimensão
trarão conclusões definitivas quanto ao valor de prognóstico do complemento
C3, MuRF1 e DYRK1A.Programa Doutoral em Biomedicin
Um modelo para suporte automatizado ao reconhecimento, extração, personalização e reconstrução de gráficos estáticos
Data charts are widely used in our daily lives, being present in regular media,
such as newspapers, magazines, web pages, books, and many others. A well constructed
data chart leads to an intuitive understanding of its underlying data
and in the same way, when data charts have wrong design choices, a redesign
of these representations might be needed. However, in most cases, these
charts are shown as a static image, which means that the original data are not
usually available. Therefore, automatic methods could be applied to extract the
underlying data from the chart images to allow these changes. The task of
recognizing charts and extracting data from them is complex, largely due to the
variety of chart types and their visual characteristics.
Computer Vision techniques for image classification and object detection are
widely used for the problem of recognizing charts, but only in images without
any disturbance. Other features in real-world images that can make this task
difficult are not present in most literature works, like photo distortions, noise,
alignment, etc. Two computer vision techniques that can assist this task and
have been little explored in this context are perspective detection and
correction. These methods transform a distorted and noisy chart in a clear
chart, with its type ready for data extraction or other uses. The task of
reconstructing data is straightforward, as long the data is available the
visualization can be reconstructed, but the scenario of reconstructing it on the
same context is complex.
Using a Visualization Grammar for this scenario is a key component, as these
grammars usually have extensions for interaction, chart layers, and multiple
views without requiring extra development effort.
This work presents a model for automated support for custom recognition, and
reconstruction of charts in images. The model automatically performs the
process steps, such as reverse engineering, turning a static chart back into its
data table for later reconstruction, while allowing the user to make modifications
in case of uncertainties. This work also features a model-based architecture
along with prototypes for various use cases. Validation is performed step by
step, with methods inspired by the literature. This work features three use
cases providing proof of concept and validation of the model.
The first use case features usage of chart recognition methods focused on
documents in the real-world, the second use case focus on vocalization of
charts, using a visualization grammar to reconstruct a chart in audio format,
and the third use case presents an Augmented Reality application that
recognizes and reconstructs charts in the same context (a piece of paper)
overlaying the new chart and interaction widgets. The results showed that with
slight changes, chart recognition and reconstruction methods are now ready for
real-world charts, when taking time, accuracy and precision into consideration.Os gráficos de dados são amplamente utilizados na nossa vida diária, estando
presentes nos meios de comunicação regulares, tais como jornais, revistas,
páginas web, livros, e muitos outros. Um gráfico bem construído leva a uma
compreensão intuitiva dos seus dados inerentes e da mesma forma, quando
os gráficos de dados têm escolhas de conceção erradas, poderá ser
necessário um redesenho destas representações. Contudo, na maioria dos
casos, estes gráficos são mostrados como uma imagem estática, o que
significa que os dados originais não estão normalmente disponíveis. Portanto,
poderiam ser aplicados métodos automáticos para extrair os dados inerentes
das imagens dos gráficos, a fim de permitir estas alterações. A tarefa de
reconhecer os gráficos e extrair dados dos mesmos é complexa, em grande
parte devido à variedade de tipos de gráficos e às suas características visuais.
As técnicas de Visão Computacional para classificação de imagens e deteção
de objetos são amplamente utilizadas para o problema de reconhecimento de
gráficos, mas apenas em imagens sem qualquer ruído. Outras características
das imagens do mundo real que podem dificultar esta tarefa não estão
presentes na maioria das obras literárias, como distorções fotográficas, ruído,
alinhamento, etc. Duas técnicas de visão computacional que podem ajudar
nesta tarefa e que têm sido pouco exploradas neste contexto são a deteção e
correção da perspetiva. Estes métodos transformam um gráfico distorcido e
ruidoso em um gráfico limpo, com o seu tipo pronto para extração de dados
ou outras utilizações. A tarefa de reconstrução de dados é simples, desde que
os dados estejam disponíveis a visualização pode ser reconstruída, mas o
cenário de reconstrução no mesmo contexto é complexo.
A utilização de uma Gramática de Visualização para este cenário é um
componente chave, uma vez que estas gramáticas têm normalmente
extensões para interação, camadas de gráficos, e visões múltiplas sem exigir
um esforço extra de desenvolvimento.
Este trabalho apresenta um modelo de suporte automatizado para o
reconhecimento personalizado, e reconstrução de gráficos em imagens
estáticas. O modelo executa automaticamente as etapas do processo, tais
como engenharia inversa, transformando um gráfico estático novamente na
sua tabela de dados para posterior reconstrução, ao mesmo tempo que
permite ao utilizador fazer modificações em caso de incertezas. Este trabalho
também apresenta uma arquitetura baseada em modelos, juntamente com
protótipos para vários casos de utilização. A validação é efetuada passo a
passo, com métodos inspirados na literatura. Este trabalho apresenta três
casos de uso, fornecendo prova de conceito e validação do modelo.
O primeiro caso de uso apresenta a utilização de métodos de reconhecimento
de gráficos focando em documentos no mundo real, o segundo caso de uso
centra-se na vocalização de gráficos, utilizando uma gramática de visualização
para reconstruir um gráfico em formato áudio, e o terceiro caso de uso
apresenta uma aplicação de Realidade Aumentada que reconhece e reconstrói
gráficos no mesmo contexto (um pedaço de papel) sobrepondo os novos
gráficos e widgets de interação. Os resultados mostraram que com pequenas
alterações, os métodos de reconhecimento e reconstrução dos gráficos estão
agora prontos para os gráficos do mundo real, tendo em consideração o
tempo, a acurácia e a precisão.Programa Doutoral em Engenharia Informátic
The Adirondack Chronology
The Adirondack Chronology is intended to be a useful resource for researchers and others interested in the Adirondacks and Adirondack history.https://digitalworks.union.edu/arlpublications/1000/thumbnail.jp
Registration accuracy of the optical navigation system for image-guided surgery
Abstract. During the last decades, image-guided surgery has been a vastly growing method during medical operations. It provides a new opportunity to perform surgical operations with higher accuracy and reliability than before. In image-guided surgery, a navigation system is used to track the instrument’s location and orientation during the surgery. These navigation systems can track the instrument in many ways, the most common of which are optical tracking, mechanical tracking, and electromagnetic tracking. Usually, the navigation systems are used primarily in surgical operations located in the head and spine area. For this reason, it is essential to know the registration accuracy and thus the navigational accuracy of the navigation system, and how different registration methods might affect them.
In this research, the registration accuracy of the optical navigation system is investigated by using a head phantom whose coordinate values of holes in the surface are measured during the navigation after different registration scenarios. Reference points are determined using computed tomography images taken from the head phantom. The absolute differences of the measured points to the corresponding reference points are calculated and the results are illustrated using bar graphs and three-dimensional point clouds. MATLAB is used to analyze and present the results.
Results show that registration accuracy and thus also navigation accuracy are primarily affected by how the first three registration points are determined for the navigation system at the beginning of the registration. This should be considered in future applications where the navigation system is used in image-guided surgery.Kuvaohjatun kirurgian optisen navigointilaitteen rekisteröintitarkkuus. Tiivistelmä. Viimeisten vuosikymmenien aikana kuvaohjattu kirurgia on yleistynyt laajalti lääketieteellisten toimenpiteiden aikana ja se tarjoaa entistä paremman mahdollisuuden tarkkaan ja luotettavaan hoitoon. Kuvaohjatussa kirurgiassa navigointilaitteisto seuraa käytetyn instrumentin paikkaa ja orientaatiota operaation aikana. Navigointilaitteistoilla on erilaisia toimintaperiaatteita, joiden perusteella ne seuraavat instrumenttia. Yleisimmin käytetyt navigointilaitteistot perustuvat optiseen, mekaaniseen, tai sähkömagneettiseen seurantaan. Yleensä kuvaohjattua kirurgiaa käytetään pään ja selkärangan alueen kirurgisissa operaatioissa, joten on erittäin tärkeää, että navigointilaitteiston rekisteröinti- ja siten myös navigointitarkkuus tunnetaan, sekä erilaisten rekisteröintitapojen mahdolliset vaikutukset kyseisiin tarkkuuksiin.
Tässä tutkimuksessa optisen navigointilaitteen rekisteröintitarkkuutta tutkitaan päämallin avulla, jonka pintaan luotujen reikien koordinaattiarvot mitataan navigointitilanteessa erilaisten rekisteröintitapojen jälkeen. Referenssipisteet kyseisille mittauspisteille määritetään päämallin tietokonetomografiakuvista. Mitattujen pisteiden, sekä vastaavien referenssipisteiden väliset absoluuttiset erot lasketaan ja tulokset esitetään palkkikuvaajien, sekä kolmiulotteisten pistepilvien avulla käyttäen apuna MATLAB-ohjelmistoa.
Tulokset osoittavat, että rekisteröintitarkkuuteen ja siten navigointitarkkuuteen vaikuttaa eniten rekisteröintitilanteen alussa määritettävien kolmen ensimmäisen rekisteröintipisteen sijainti ja tämä tuleekin ottaa huomioon jatkossa tilanteissa, joissa navigointilaitetta käytetään kuvaohjatussa kirurgiassa
Karttatypografia: luettavuuden parantaminen kirjainmuotoilun keinoin topografisissa kartoissa
This thesis examines the legibility of type on maps and aims to find out ways to improve it through type design. As type often is an integral part of maps – something that helps the map user navigate, understand, and perceive a wide range of information in an effective way – type design and legibility must be regarded as important design elements. However, even though cartography and typography have extensive theoretical bases, the subject of legibility has not been comprehensively researched in cartographic context. Thus, by combining type design theory and scientific legibility studies with cartographic theory, the legibility of type on maps could be improved.
The topic is first studied by an extensive literature review to cover existing concepts and theories of cartography, cartographic typography, and typography. After a competent knowledge basis of these concepts and theories is acquired, the findings are utilised in the design component. The design component is a type family designed specifically to be used with topographic maps: it consists of two elements, a project description that follows the design process of the type family, relating design choices to the theoretical findings and perspectives presented in the literary review, and the finished type family. In conclusion of the design component, several visual studies are made both to compare the design component (type family) to other relevant typefaces, and to validate the possible functionality of the design component in the chosen cartographic application (topographic map).
A broad understanding of the topics of the literature review was formed. Cartographic theory observed the overall nature of maps and specified the various map elements and their intended uses. Cartographic typography deepened the understanding of type on maps – it highlighted the specific needs that must be taken into consideration, demonstrated the diversity of typographic situations that might occur, and presented a large set of guidelines to help the mapmaker to achieve better results. Typography and type design focused on the micro-level of type: how the minor design choices affect the whole, and furthermore, through legibility studies, validated certain views and brought new topics into consideration. By combining theoretical literature from these domains, this thesis helped to form a foundation for an improved framework for type de-sign for (topographic) maps. Furthermore, the domains of cartographic typography and typography and type design gave clear suggestions on how the legibility of type on topographic maps can be improved: legibility of type in this context constitutes from multiple components that must be both taken into consideration and be applied to processes of mapmaking and type design.Tässä opinnäytetyössä tutkitaan karttatypografiaa ja pyritään löytämään keinoja parantaa luettavuutta kirjainmuotoilun keinoin. Teksti on usein elimellinen osa karttoja: se helpottaa kartan käyttäjää navigoimaan ja sisäistämään suuren määrän informaatiota tehokkaasti. Siispä kirjainmuotoilua ja luettavuutta tulee pitää tärkeinä karttasuunnittelun työkaluina. Vaikka sekä kartografiassa että typografiassa on olemassa laajat teoreettiset perustat, luettavuutta ei ole kattavasti tutkittu kartografisessa kontekstissa. Yhdistämällä kirjainmuotoilun ja tieteelliset luettavuustutkimukset kartografiseen teoriaan, karttatekstien luettavuutta voidaan parantaa.
Aluksi tutustutaan olemassa oleviin konsepteihin ja kartografisiin teorioihin kattavan kirjallisuuskatsauksen avulla. Kun tarpeellinen tietopohja on rakennettu, saavutettua tietämystä hyödynnetään opinnäytetyön projektiosassa, joka tässä tapauksessa on topografisten karttojen yhteydessä käytettävä kirjainperhe. Projektiosio on kaksijakoinen ja pitää sisällään sekä valmiin kirjainperheen, että projektikuvauksen. Projektikuvaus seuraa suunnitteluprosessia ja peilaa tehtyjä valintoja kirjallisuuskatsauksessa esiteltyihin löydöksiin. Projektiosion päätelmässä tutkitaan visuaalisesti kirjainperheen toimintaa ja käyttökelpoisuutta topografisessa karttaympäristössä, sekä verrataan kirjainperheen toimivuutta suhteessa muihin kirjaintyyppeihin.
Tutkimuksen perusteella muodostuu laaja ymmärrys aiheesta. Kartografinen teoria valottaa yleisesti karttojen olemusta ja toimintaa, sekä esittelee erilaisia karttalementtejä ja niiden toimintatapoja. Karttatypografian teoria syventää ymmärrystä tekstin käyttäytymisestä karttaympäristössä, esittelee karttatypografian erityispiirteitä, ja tarjoaa laajan karttatypografisen ohjeiston. Typografian ja kirjainmuotoilun teoria keskittyy mikrotason aiheisiin: kuinka vähäpätöisiltä vaikuttavat suunnitteluvalinnat vaikuttavat kokonaisuuteen, ja kuinka luettavuustutkimukset auttavat näkemään asioita uudessa valossa. Tämä opinnäytetyö auttaa parantamaan kirjainmuotoilua (topografisessa) karttaympäristössä yhdistämällä edellä mainittujen alojen teorioita keskenään ja pohjustamalla paranneltuja suunniteluvalintoja. Yhdistetty teoria viittaa selkeästi siihen, että luettavuus karttaympäristössä koostuu lukuisista osatekijöistä – nämä osatekijät tulee ymmärtää, ottaa huomioon, ja soveltaa sekä karttojen että niille suunniteltujen kirjaintyyppien suunnitteluprosesseissa
Non-Rigid Liver Registration for Laparoscopy using Data-Driven Biomechanical Models
During laparoscopic liver resection, the limited access to the organ, the small field of view and lack of palpation can obstruct a surgeon’s workflow. Automatic navigation systems could use the images from preoperative volumetric organ scans to help the surgeons find their target (tumors) and risk-structures (vessels) more efficiently. This requires the preoperative data to be fused (or registered) with the intraoperative scene in order to display information at the correct intraoperative position.
One key challenge in this setting is the automatic estimation of the organ’s current intra-operative deformation, which is required in order to predict the position of internal structures. Parameterizing the many patient-specific unknowns (tissue properties, boundary conditions, interactions with other tissues, direction of gravity) is very difficult. Instead, this work explores how to employ deep neural networks to solve the registration problem in a data-driven manner. To this end, convolutional neural networks are trained on synthetic data to estimate an organ’s intraoperative displacement field and thus its current deformation. To drive this estimation, visible surface cues from the intraoperative camera view must be supplied to the networks. Since reliable surface features are very difficult to find, the networks are adapted to also find correspondences between the pre- and intraoperative liver geometry automatically. This combines the search for correspondences with the biomechanical behavior estimation and allows the networks to tackle the full non-rigid registration problem in one single step. The result is a model which can quickly predict the volume deformation of a liver, given only sparse surface information. The model combines the advantages of a physically accurate biomechanical simulation with the speed and powerful feature extraction capabilities of deep neural networks.
To test the method intraoperatively, a registration pipeline is developed which constructs a map of the liver and its surroundings from the laparoscopic video and then uses the neural networks to fuse the preoperative volume data into this map. The deformed organ volume can then be rendered as an overlay directly onto the laparoscopic video stream. The focus of this pipeline is to be applicable to real surgery, where everything should be quick and non-intrusive. To meet these requirements, a SLAM system is used to localize the laparoscopic camera (avoiding setup of an external tracking system), various neural networks are used to quickly interpret the scene and semi-automatic tools let the surgeons guide the system.
Beyond the concrete advantages of the data-driven approach for intraoperative registration, this work also demonstrates general benefits of training a registration system preoperatively on synthetic data. The method lets the engineer decide which values need to be known explicitly and which should be estimated implicitly by the networks, which opens the door to many new possibilities.:1 Introduction
1.1 Motivation
1.1.1 Navigated Liver Surgery
1.1.2 Laparoscopic Liver Registration
1.2 Challenges in Laparoscopic Liver Registration
1.2.1 Preoperative Model
1.2.2 Intraoperative Data
1.2.3 Fusion/Registration
1.2.4 Data
1.3 Scope and Goals of this Work
1.3.1 Data-Driven, Biomechanical Model
1.3.2 Data-Driven Non-Rigid Registration
1.3.3 Building a Working Prototype
2 State of the Art
2.1 Rigid Registration
2.2 Non-Rigid Liver Registration
2.3 Neural Networks for Simulation and Registration
3 Theoretical Background
3.1 Liver
3.2 Laparoscopic Liver Resection
3.2.1 Staging Procedure
3.3 Biomechanical Simulation
3.3.1 Physical Balance Principles
3.3.2 Material Models
3.3.3 Numerical Solver: The Finite Element Method (FEM)
3.3.4 The Lagrangian Specification
3.4 Variables and Data in Liver Registration
3.4.1 Observable
3.4.2 Unknowns
4 Generating Simulations of Deforming Organs
4.1 Organ Volume
4.2 Forces and Boundary Conditions
4.2.1 Surface Forces
4.2.2 Zero-Displacement Boundary Conditions
4.2.3 Surrounding Tissues and Ligaments
4.2.4 Gravity
4.2.5 Pressure
4.3 Simulation
4.3.1 Static Simulation
4.3.2 Dynamic Simulation
4.4 Surface Extraction
4.4.1 Partial Surface Extraction
4.4.2 Surface Noise
4.4.3 Partial Surface Displacement
4.5 Voxelization
4.5.1 Voxelizing the Liver Geometry
4.5.2 Voxelizing the Displacement Field
4.5.3 Voxelizing Boundary Conditions
4.6 Pruning Dataset - Removing Unwanted Results
4.7 Data Augmentation
5 Deep Neural Networks for Biomechanical Simulation
5.1 Training Data
5.2 Network Architecture
5.3 Loss Functions and Training
6 Deep Neural Networks for Non-Rigid Registration
6.1 Training Data
6.2 Architecture
6.3 Loss
6.4 Training
6.5 Mesh Deformation
6.6 Example Application
7 Intraoperative Prototype
7.1 Image Acquisition
7.2 Stereo Calibration
7.3 Image Rectification, Disparity- and Depth- estimation
7.4 Liver Segmentation
7.4.1 Synthetic Image Generation
7.4.2 Automatic Segmentation
7.4.3 Manual Segmentation Modifier
7.5 SLAM
7.6 Dense Reconstruction
7.7 Rigid Registration
7.8 Non-Rigid Registration
7.9 Rendering
7.10 Robotic Operating System
8 Evaluation
8.1 Evaluation Datasets
8.1.1 In-Silico
8.1.2 Phantom Torso and Liver
8.1.3 In-Vivo, Human, Breathing Motion
8.1.4 In-Vivo, Human, Laparoscopy
8.2 Metrics
8.2.1 Mean Displacement Error
8.2.2 Target Registration Error (TRE)
8.2.3 Champfer Distance
8.2.4 Volumetric Change
8.3 Evaluation of the Synthetic Training Data
8.4 Data-Driven Biomechanical Model (DDBM)
8.4.1 Amount of Intraoperative Surface
8.4.2 Dynamic Simulation
8.5 Volume to Surface Registration Network (V2S-Net)
8.5.1 Amount of Intraoperative Surface
8.5.2 Dependency on Initial Rigid Alignment
8.5.3 Registration Accuracy in Comparison to Surface Noise
8.5.4 Registration Accuracy in Comparison to Material Stiffness
8.5.5 Champfer-Distance vs. Mean Displacement Error
8.5.6 In-vivo, Human Breathing Motion
8.6 Full Intraoperative Pipeline
8.6.1 Intraoperative Reconstruction: SLAM and Intraoperative Map
8.6.2 Full Pipeline on Laparoscopic Human Data
8.7 Timing
9 Discussion
9.1 Intraoperative Model
9.2 Physical Accuracy
9.3 Limitations in Training Data
9.4 Limitations Caused by Difference in Pre- and Intraoperative Modalities
9.5 Ambiguity
9.6 Intraoperative Prototype
10 Conclusion
11 List of Publications
List of Figures
Bibliograph
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