Extended finite automata over groups

We consider a simple and natural extension of a finite automaton, namely an element of a given group is associated with each configuration. An input string is accepted if and only if the neutral element of the group is associated to a final configuration reached by the automaton. The accepting power is smaller when abelian groups are considered, in comparison with the non-abelian groups. We prove that this is due to the commutativity. Each language accepted by a finite automaton over an abelian group is actually a unordered vector language. We get a new characterization of the context-free languages as soon as the considered group is the binary free group. The result cannot be carried out in the deterministic case. Some remarks about other groups are also presented

CONCEPÇÕES DE PROFESSORES DOS ANOS INICIAIS SOBRE A RESOLUÇÃO DE PROBLEMAS NO ENSINO DE MATEMÁTICA

Este trabalho tem como ponto norteador saber o que os professores dos Anos Iniciais estão se referindo quando abordam acerca da Resolução de Problemas, e ainda se a resolução for utilizada com o campo aditivo, quais são suas ações e que ideias são exploradas e denominam. Sendo assim, a pesquisa tem como objetivo compreender as concepções de professores dos Anos Iniciais sobre a Resolução de Problemas no Ensino de Matemática e como a temática é explorada ao trabalhar com o campo aditivo. Como aporte teórico para a fundamentação da pesquisa foi feita a análise bibliográfica de autores que abordam acerca da Resolução de Problemas, e suas diferentes concepções, e também do campo conceitual aditivo de Vergnaud. Utilizando-se de uma pesquisa qualitativa, seis professores que ensinam Matemática nos Anos Iniciais do Ensino Fundamental das escolas da rede pública municipal de um pequeno município da região do Alto Vale do Itajaí responderam a um questionário realizado de forma on-line. A análise dos dados obtidos foi realizada buscando resposta às seguintes questões: Como será que professores que ensinam Matemática nos Anos Iniciais compreendem a Resolução de Problemas? Como esse professor utiliza a Resolução de Problemas na sala de aula com seus estudantes? Como esse professor utiliza a Resolução de Problemas no Campo Aditivo? Os dados analisados por meio da Análise Textual Discursiva irão permitir ao final concluir quais as concepções de Resolução de Problemas dos professores participantes da pesquisa e de que modo os mesmos utilizam o método em relação com o campo conceitual aditivo. É possível perceber que, em sua maioria, os professores ensinam Matemática para resolver problemas, sendo essa uma das concepções trazidas por meio dos autores da fundamentação teórica, e não trabalham com a Resolução de Problemas para ensinar Matemática. Outra preferência dos docentes foi a concepção de ensinar sobre Resolução de Problemas, que indica utilização apenas como uma ferramenta para o ensino e não como ponto de partida para o mesmo. Quanto ao campo aditivo, professores concebem os conceitos, objetivos e as categorias que compõem Resolução de Problemas.o campo aditivo, utilizando exemplos que se aproximam da realidade dos alunos

Capacity Bounded Grammars and Petri Nets

A capacity bounded grammar is a grammar whose derivations are restricted by assigning a bound to the number of every nonterminal symbol in the sentential forms. In the paper the generative power and closure properties of capacity bounded grammars and their Petri net controlled counterparts are investigated

Pure 2D picture grammars and languages

A new syntactic model, called pure two-dimensional (2D) context-free grammar (P2DCFG), is introduced based on the notion of pure context-free string grammar. The rectangular picture generative power of this 2D grammar model is investigated. Certain closure properties are obtained. An analogue of this 2D grammar model called pure 2D hexagonal context-free grammar (P2DHCFG) is also considered to generate hexagonal picture arrays on triangular grids

The Transnationalization and Commodification of Care Labor: A Comparative Study on Contemporary Issues in Au Pair Tourism in Norway and Australia with a Strong Focus on Employment Legislation

Master's thesis in International Hospitality ManagementAu Pair tourism is an increasingly popular activity in many places around the world. Au Pair tourism has its roots in Switzerland in the mid-19th century and has ever since developed from a formerly upper-class cultural exchange phenomenon to one that now spans a broader socio-economic spectrum regarding both, host families and Au Pairs. Europe has tried to formalize Au Pair employment via a supranational European Agreement on Au Pair Placement in 1969. A handful of countries, among them Norway, have ratified and adopted this agreement and their Au Pair schemes build upon this more than four decades old legal framework. Norway’s Au Pair market is thus highly formalized and regulated yet does not consider Au Pairs as workers which causes controversy and high rates of foreign workforce exploitation. Previous scholarship on this issue claims that Norway is part of a global care chain meaning the Global North exploiting the Global South. Australia, a prime Au Pair destination, has a largely unregulated Au Pair market and does not have a dedicated Au Pair scheme. In Australia exploitative working conditions for young migratory care workers seem to be the rule rather than the exception. This study investigates the advantages and disadvantages of unregulated and regulated Au Pair markets using the two cases Australia and Norway. The study was preceded by a pre-study which was conducted in the second half of 2018 in Australia. A total of 16 semi-structured interviews with researchers, organizations, and Au Pairs in Australia and Norway have been conducted and build the foundation for any conclusions in this paper. This paper also contains a model that allows to estimate the nature of the relation between certain sending and host countries, called ECDI (Econo-Cultural Distance Index). Lastly, suggestions for improvement to both the Australian and the Norwegian Au Pair employment regulations.submittedVersio

Social big data mining for the sustainable mobility and transport transition: findings from a large-scale cross-platform analysis

Abstract The paper reports findings from a study that examining how cross-platform social media analysis can help to map the digital discourse on sustainable mobility and sustainable transport, and enhance the understanding of sociotechnical low-carbon transport transitions. Using the hashtag search queries #sustainabletransport and #sustainablemobility, 33,121 Tweets (2013–2021) and 8,089 Instagram images including captions (2017/2018–2021) were scraped using the Python modules Twint and Instaloader. Quantitative text and sentiment analyses were applied to the Tweets and image captions. Additionally, an automated machine learning-based image analysis of the Instagram images was conducted using object detection via OpenCV. Synthesized results formed the base for a cross-platform analysis inspired by Rogers’ method comprising hot topics/key themes, user mentions, sentiment polarity, and co-hashtags. Notably, electromobility emerged as a prominent theme, particularly on Instagram, while #sustainabletransport was closely associated with active travel, notably bicycling, and #sustainablemobility showcased a dominance of electromobility discourse. The study demonstrates the investigative potentials of cross-platform social media analysis studies to enhance the understanding of sociotechnical low-carbon transport transitions. Drawing on key results, the paper suggests an adapted version of the Geelsean Multi-Level Perspective on Sociotechnical Transitions

Come Fly with Me (Sustainably) : Pathways to Sustainable General Aviation and Private Pilot Training

Whereas commercial aviation is attempting to achieve the reduction of its substantial carbon footprint, general aviation’s (GA) climate change contribution is negligibly small, which is why the sector is facing other sustainability challenges mainly entailing the operation of dated technology and aircraft, increasing regulatory constraints, rising costs, noise emissions, and popular discontent, as well as remaining the last mobility sector in the world to still use leaded fuels. Throughout recent years, there have been remarkable sustainability trends in GA as well as heightened efforts to improve its emissions profile (noise, pollutants, CO2) and environmental reputation, for instance by the increased use of electric aircraft, especially for private pilot training. From a sociotechnical perspective, this mixed-methods study highlights current sustainability challenges and trends in GA as well as potential pathways towards more sustainable GA and private pilot training. Eight in-depth semi-structured interviews with Swiss and international GA stakeholders were complemented with a bilingual representative quantitative online survey (N=427) among Swiss GA stakeholders, a comparative CO2 analysis showing the emissions advantages and feasibility limits of supplementing private pilot training with lessons using electric aircraft, as well as participant observation. The data show that most Swiss GA stakeholders have increased environmental awareness and are concerned about sustainability and the environment both, in flight and other activities. Although the majority advocates for sustainable development in GA there are not one but many challenges and obstacles to a more sustainable GA. The largest challenges are the abatement of noise emissions and the facilitation of the leaded aviation gasoline (AVGAS 100LL) phaseout. The most pertinent obstacles towards sustainable GA innovation are said to be bureaucracy, overregulation and reluctance in the civil aviation authorities, high costs, averseness to risk and innovation, as well as a trend of decline in GA activity due to continuous demographic change. No single sustainability pathway but rather a mix of immediate and long-term sustainability measures was identified. Despite its current limitations, electric aviation proves to be one of the most feasible pathways to sustainable private pilot training. For more sustainable GA, the use of more fuel-efficient planes and available unleaded fuels, propeller, and muffler retrofits, as well as is feasible short- and midterm measures. In the long run, electric and hybrid aviation as well as bio- and synfuels are likely to become attractive options for GA. The study shows the importance of sustainable development in GA and private pilot training, not because it will majorly contribute to climate change mitigation, but because it will ensure the improvement of its negative environmental reputation and societal acceptance, which will be vital to ensuring the survival of the GA sector.