Light On String Solving: Approaches to Efficiently and Correctly Solving String Constraints

Widespread use of string solvers in formal analysis of string-heavy programs has led to a growing demand for more efficient and reliable techniques which can be applied in this context, especially for real-world cases. Designing an algorithm for the (generally undecidable) satisfiability problem for systems of string constraints requires a thorough understanding of the structure of constraints present in the targeted cases. We target the aforementioned case in different perspectives: We present an algorithm which works by reformulating the satisfiability of bounded word equations as a reachability problem for non-deterministic finite automata. Secondly, we present a transformation-system-based technique to solving string constraints. Thirdly, we investigate benchmarks presented in the literature containing regular expression membership predicates and design a decission procedure for a PSPACE-complete sub-theory. Additionally, we introduce a new benchmarking framework for string solvers and use it to showcase the power of our algorithms via an extensive empirical evaluation over a diverse set of benchmarks

O comportamento do investimento direto estrangeiro em anos de crise: seus efeitos no brasil no período 2008-2020

Desde o maior surgimento das empresas multinacionais na metade do século XX, o investimento direto estrangeiro tornou-se uma das ferramentas fundamentais para a internacionalização das empresas. No Brasil, este processo ganhou força na década de 1990, quando o governo dependia do IDE para que ajudasse a atingir objetivos econômicos. Com o aumento do fluxo de IDEno país, o Brasil se tornou, a partir de 1996, o principal receptordeste tipo de investimento estrangeiro daAmérica Latina e Caribe, e um dos principais no mundo. O IDE é considerado capital de risco, pois possui baixa liquidez e há incerteza no prazo de retorno e na rentabilidade do capital investido. Em momentos de crises econômicas, esta incerteza tende a crescer, levando à contração dos IDEs. A atração de IDE depende de fatores nacionais como o tamanho e crescimento do mercado, a disponibilidade de mão-de-obra e osseus custos, os níveis de inflação e de endividamento externo. No século XXI, já ocorreram duas crises econômicas mundiais, a crise do subprimeem 2008 e a crise da pandemia da COVID-19, em 2020. Dado estes cenários, o objetivo do trabalho será analisar ocomportamento do fluxo de IDE do Brasil em momentos de crise, especificamente durante as crises financeiras de 2008 e a da pandemia da COVID-19, e seu impacto em indicadores econômicos selecionados do país, sendo esses PIB, taxa de juros e taxa de câmbio,visto que esses são determinantes importantes do fluxo de IDE, e apresentam variações significativas em momentos de crise. A hipótese do trabalho é que o comportamento dos fluxos de IDE no Brasil tem relação com o desempenho dos indicadores econômicos selecionados. A principal conclusão deste trabalho é que as mudanças nos fluxos de IDE em momentos de crise estão correlacionadas aos comportamentos dos indicadores econômicos selecionados. A situação da economia do país não gera grande atratividade do IDE, assim como a desvalorização do câmbio brasileiro. Por fim, as participações de ambos osfluxos de IDE sofreram consideráveis reduções na composição do PIB brasileiro.Since the emergence of multinational companies in the mid-twentieth century, foreign direct investment has become one of the key tools for companies’ internationalization. In Brazil, this process gained strength in the 1990s, when the government relied on FDI to help achieve economic goals. With the increase in the FDI flow into the country, Brazil has become, since 1996, the main recipient of this type of foreign investment in Latin America and the Caribbean, and one of the main ones in the world. FDI is considered risk capital, as it has low liquidity and there is uncertainty regarding the return period and profitability of the invested capital. In times of economic crisis, this uncertainty tends to grow, leading to a contraction of FDI. The attraction of FDI depends on national factors such as the market size and its growth, the labor supply and its costs, the inflation levels and external debt. In the 21st century, two global economic crises have already occurred, the subprime crisis in 2008 and the COVID-19 pandemic crisis in 2020. Given these scenarios, the purpose of this study is to analyze FDI’s flow behavior in Brazil in timesof crisis, specifically during the 2008 financial crisis and the COVID-19 pandemic crisis, and their impact on the country’s selected economic indicators, namely GDP, interest rate and exchange rate, as these are important determinants of FDI flow and show significant variations in times of crisis. The study hypothesizes that the behavior of FDI flows in Brazil is related to the performance of these selected economic indicators. The main conclusion of this essay is that the changes in FDI flow in times of crisis are correlated with the behavior of the selected economic indicators. The situation of the country's economy does not generate great attractiveness for foreign direct investment flows. Based on data from the period 2008 -2020, analyzed in this study, it was noticed that the low interest rates and profitability of the real against the dollar do not generate the high expected return on FDI, which would compensate for its high level of risk. The low interest rate in times of economic crisis, in 2008 and 2020, inhibits the attractiveness of FDI, as well as the devaluation of the Brazilian exchange rate. Finally, the shares of both FDI flows suffered considerable reductions in the composition of the Brazilian GDP

Criador e criatura : a invenção de uma persona-objeto

Criador e Criatura: a invenção de uma persona-objeto trata da criação de uma persona, tendo como objetivo apresentar uma possibilidade poética em fotografia e vídeo. Toma por base o conceito de terceiro analítico na psicanálise, apresentando a “ferramenta persona” e sua produção resultante, assim como discute os aportes e os desdobramentos poéticos trazidos pelos meios escolhidos para sua criação, permeados pelos conceitos de máscara levantados por Hans Belting (2017) e Paulo Sérgio Faitanin (2006).Creator and Creature: the invention of a persona-object deals with the creation of a persona, having as its objective to introduce a poetic possibility in photography and video. It takes as reference the concept of the analytical third in psychoanalysis, introducing the “persona tool” and its resulting works, as well as discusses the poetic contributions and unfoldings brought by such mediums to its creation, permeated by the concepts of mask brought up by Hans Belting (2017) and Paulo Sergio Faitanin (2006)