Unfolding-based Partial Order Reduction

Partial order reduction (POR) and net unfoldings are two alternative methods to tackle state-space explosion caused by concurrency. In this paper, we propose the combination of both approaches in an effort to combine their strengths. We first define, for an abstract execution model, unfolding semantics parameterized over an arbitrary independence relation. Based on it, our main contribution is a novel stateless POR algorithm that explores at most one execution per Mazurkiewicz trace, and in general, can explore exponentially fewer, thus achieving a form of super-optimality. Furthermore, our unfolding-based POR copes with non-terminating executions and incorporates state-caching. Over benchmarks with busy-waits, among others, our experiments show a dramatic reduction in the number of executions when compared to a state-of-the-art DPOR.Comment: Long version of a paper with the same title appeared on the proceedings of CONCUR 201

Altering the stability of the Cdc8 overlap region modulates the ability of this tropomyosin to bind cooperatively to actin and regulate myosin.

Tropomyosin (Tm) is an evolutionarily conserved ?-helical coiled-coil protein, dimers of which form end-to-end polymers capable of associating with and stabilising actin-filaments and regulate myosin function. The fission yeast, Schizosaccharomyces pombe, possesses a single essential Tm, Cdc8, which can be acetylated on its amino terminal methionine to increase its affinity for actin and enhance its ability to regulate myosin function. We have designed and generated a number of novel Cdc8 mutant proteins with amino terminal substitutions to explore how stability of the Cdc8-polymer overlap region affects the regulatory function of this Tm. By correlating the stability of each protein, its propensity to form stable polymers, its ability to associate with actin and to regulate myosin, we have shown the stability of the amino terminal of the Cdc8 ?-helix is crucial for Tm function. In addition we have identified a novel Cdc8 mutant with increased amino-terminal stability, dimers of which are capable of forming Tm-polymers significantly longer than the wild-type protein. This protein had a reduced affinity for actin with respect to wild type, and was unable to regulate actomyosin interactions. The data presented here are consistent with acetylation providing a mechanism for modulating the formation and stability of Cdc8 polymers within the fission yeast cell. The data also provide evidence for a mechanism in which Tm dimers form end-to-end polymers on the actin-filament, consistent with a cooperative model for Tm binding to actin

Multiscale Imaging of Evapotranspiration

Evapotranspiration (ET; evaporation + transpiration) is central to a wide range of biological, chemical, and physical processes in the Earth system. Accurate remote sensing of ET is challenging due to the interrelated and generally scale dependent nature of the physical factors which contribute to the process. The evaporation of water from porous media like sands and soils is an important subset of the complete ET problem. Chapter 1 presents a laboratory investigation into this question, examining the effects of grain size and composition on the evolution of drying sands. The effects of composition are found to be 2-5x greater than the effects of grain size, indicating that differences in heating caused by differences in reflectance may dominate hydrologic differences caused by grain size variation. In order to relate the results of Chapter 1 to the satellite image archive, however, the question of information loss between hyperspectral (measurements at 100s of wavelength intervals) laboratory measurements and multispectral (≤ 12 wavelength intervals) satellite images must be addressed. Chapter 2 focuses on this question as applied to substrate materials such as sediment, soil, rock, and non-photosynthetic vegetation. The results indicate that the continuum that is resolved by multispectral sensors is sufficient to resolve the gradient between sand-rich and clay-rich soils, and that this gradient is also a dominant feature in hyperspectral mixing spaces where the actual absorptions can be resolved. Multispectral measurements can be converted to biogeophysically relevant quantities using spectral mixture analysis (SMA). However, retrospective multitemporal analysis first requires cross-sensor calibration of the mixture model. Chapter 3 presents this calibration, allowing multispectral image data to be used interchangeably throughout the Landsat 4-8 archive. In addition, a theoretical explanation is advanced for the observed superior scaling properties of SMA-derived fraction images over spectral indices. The physical quantities estimated by the spectral mixture model are then compared to simultaneously imaged surface temperature, as well as to the derived parameters of ET Fraction and Moisture Availability. SMA-derived vegetation abundance is found to produce substantially more informative ET maps, and SMA-derived substrate fraction is found to yield a surprisingly strong linear relationship with surface temperature. These results provide context for agricultural applications. Chapter 5 investigates the question of mapping and monitoring rice agricultural using optical and thermal satellite image time series. Thermal image time series are found to produce more accurate maps of rice presence/absence, but optical image time series are found to produce more accurate maps of rice crop timing. Chapter 6 takes a more global approach, investigating the spatial structure of agricultural networks for a diverse set of landscapes. Surprisingly consistent scaling relations are found. These relations are assessed in the context of a network-based approach to land cover analysis, with potential implications for the scale dependence of ET estimates. In sum, this thesis present a novel approach to improving ET estimation based on a synthesis of complementary laboratory measurements, satellite image analysis, and field observations. Alone, each of these independent sources of information provides novel insights. Viewed together, these insights form the basis of a more accurate and complete geophysical understanding of the ET phenomenon

An assessment of how brand awareness influences brand recognition throught product placement, applied to the automotive industry and computers

In an era where traditional forms of communication have been losing their effectiveness due to consumer saturation, marketers have been looking for alternative ways to reach their target. Therefore, in a scenario where brands compete fiercely to be seen, heard, but especially remembered in consumers’ minds, product placement presents itself as an attractive and distinctive alternative to be explored. Despite the growth of product placement in recent years, most empirical studies focus solely on assessing viewers recall and attitudes towards product placement. Thus, this research further contributes to existing literature by introducing the dimension of brand recognition. Moreover, it will direct its focus towards cars and computers product placement within movies, allowing for new and unique insights. This procedure also allows for an interesting segmentation of the distinct group of consumers which are likely to recognize brands in this context. The present research is quantitative natured and comprises a brand awareness test and a brand recognition experiment. The brand awareness test allowed to group the brands into three distinct groups of awareness: top-of-mind, spontaneous awareness and the lowest level of awareness (Aaker, 1991). While the brand recognition experiment aimed to study consumers’ ability to identify the brand’s name through visual cues and other brand attributes. The results suggest that there is a direct relationship between brand awareness and brand recognition in both product categories analyzed. It was also possible to identify profiles of brand recognition considering socio-demographic characteristics, viewing frequency of movies, knowledge of the product category, and consumer’s attitude towards product placement.Numa época em que as formas tradicionais de comunicação têm vindo a perder a sua eficácia devido à saturação do consumidor a estes estímulos, as marcas têm procurado formas alternativas para comunicar com o seu público alvo. Neste cenário, onde as marcas competem ferozmente para serem vistas, ouvidas, mas especialmente lembradas nas mentes dos consumidores, o "product placement" apresenta-se como uma alternativa atrativa e distinta a ser explorada. Apesar do crescimento do product placement nos últimos anos, a maioria dos estudos empíricos concentra-se unicamente na avaliação do "recall" e das atitudes face ao "product placement". Neste sentido, esta pesquisa contribui para a literatura existente introduzindo a dimensão do reconhecimento da marca. Além disso, direcionará o seu foco para o "product placement" de carros e computadores em filmes. Este procedimento permite também uma segmentação de diferentes grupos de consumidores de forma a identificar perfis de reconhecimento. A presente pesquisa é de caráter quantitativo e compreende um teste de notoriedade e um teste de reconhecimento de marcas. O teste de notoriedade permitiu agrupar as marcas em três grupos distintos de notoriedade: "top-of-mind", notoriedade espontânea e notoriedade baixa (Aaker, 1991). Ao passo que o teste de reconhecimento da marca pretendeu estudar a capacidade dos consumidores em identificar o nome da marca através dos seus elementos. Os resultados sugerem que existe uma relação direta entre a notoriedade da marca e o seu reconhecimento, para ambas as categorias de produtos analisadas. Foi também possível identificar perfis de reconhecimento considerando características sociodemográficas, frequência de visualização de filmes, conhecimento da categoria de produto e atitude do consumidor em relação ao "product placement"

Interview with Dunja Fehimović and Rebecca Ogden

In this interview, Dunja Fehimović (Lecturer in Hispanic Studies at the Newcastle University) and Rebecca Ogden (Lecturer in Latin American Studies at the University of Kent) examine how perceptions of national image and reputation are shaped in the continent, which is the focs of their book "Branding Latin America: Strategies, Aims, Resistance". They discuss the way Latin America has experienced global visibility and competitiveness since colonial times and argue that the production of an uneven playing field in the world makes the continent an interesting case of analysis in terms of branding. While the countries in the region are still perceived as peripheral, branding strategies have been seen as a means to intervene in the global system to retell national storylines or shed unfavourable ones --with uneven results in each of the countries that have attempted it

Resilience in Industry 4.0 Digital Infraestructures and Platforms

A indústria 4.0 consiste numa mudança de paradigma de produção automatizada para um conceito de produção inteligente, onde todos os ativos físicos estão conectados e podem interagir entre eles via protocolos de internet. Estes ativos são agora chamados de Sistemas Ciber-Físicos (CPS-Cyber-Physical Systems) e o sistema de produção passa a ser um sistema de produção ciber-fisico (CPPS). Estes sistemas comprometem tecnologias como IoT, produção baseada em Cloud e smart manufacturing, que são responsáveis por digitalizar os processos de produção e negócio. A crescente complexidade das aplicações dos sistemas ciber-físicos levam a maior flexibilidade na produção, permitindo a produção de lotes pequenos a custos baixos e melhorar a qualidade no que toca ao cumprimento dos requisitos do cliente. Contudo, também causam grande vulnerabilidade a disrupções durante os processos de produção. Então, os sistemas de produção devem ser resilientes a disrupções, pelo que devem ser tomadas decisões rapidamente para reduzir o seus impactos. Com sistemas de informação mais complexos, os CPS vão lidar com novas disrupções, resultando em consequências inesperadas. Por forma a estarem preparadas para os eventos descritos, as empresas devem procurar uma solução capaz de medir o impacto de disrupções nos processos, descobrir ações de mitigação adequadas e calcular o ganho em resiliência. As empresas que aderem ao paradigma da indústria 4.0 estão a migrar os seus sistemas de informação, inclusive sistemas de apoio a produção, para servidores em cloud. Esta mudança torna a produção mais ágil, mas ao mesmo tempo introduz novos problemas de comunicação e informação. A digitalização dos processos tornou o uso de planos de mitigação mais limitado e dependente de ferramentas digitais. Hoje em dia é importante a possibilidade de prever possíveis disrupções no sistema de produção e de informação, medir o seu impacto e criar uma base de dados com medidas de prevenção eficazes. Ciente desta necessidade, esta dissertação objetiva avaliar a eficácia de metodologias baseadas em simulação para medir o impacto de disrupções em sistemas de produção ciber-físicos e assim contribuir para a sua resiliência. Para tal, é apresentada uma metodologia cujo funcionamento está alinhado com um sistema de gestão de disrupções, e que é posteriormente testada num caso de estudo da indústria corticeira. Aqui, os resultados são avaliados baseados num modelo de simulação do sistema de produção descrito e do seu sistema de informação também.We live in a world where companies are shifting toward the industry 4.0 paradigm. One of the pillars of Industry 4.0 (i4.0) is the digitalization of physical assets and manufacturing and business processes towards the Cyber-Physical Production Systems concept (CPPSs). CPPSs are distinguished by highly versatile production processes capable of adapting to the current market conditions and manufacturing a wide range of small-batch items. As a result of modern applications of cyber-physical production systems, modified frameworks, and more complex IT infrastructures, new types of disruption events may occur. In the case of process disruption, actions must be taken in a short time to minimize the impact on production systems. Hence, companies that adhere to i4.0 enabling technologies must protect themselves against these unexpected problems by introducing disruption management solutions. This dissertation introduces a simulation-based methodology capable of evaluating the impacts of disruption events and finding suitable response actions to increase resilience in Cyber-Physical Production Systems processes