Essay 1: Expectation-Driven House Prices, Debt Default and Inflation Dynamics We contribute to the literature on dynamic stochastic general equilibrium (DSGE) models with housing collateral by including shocks to house price expectations. We also incorporate endogenous mortgage defaults that are rarely included in DSGE models with housing collateral. We use this model to study the effects of variations in house price expectations on macroeconomic dynamics and their implications for monetary policy. Model simulations show that an increase in expected future house prices leads to a decline in mortgage default rate and interest rates on household and business loans, whereas it leads to an increase in house prices, housing demand, household debt, business debt, bank leverage ratio and economic activity. In contrast to previous studies, we find that inflation is low during a house price boom. Finally, we show that monetary policy that takes into account household credit growth reduces the volatility of output and dampens a rise in housing demand, household debt and bank leverage ratio that enhances financial stability. However, a central bank that reacts to household credit growth increases the volatility of inflation. / Essay 2: House Price Expectations, Boom-Bust Cycles and Implications for Monetary Policy This essay examines the role of household expectations about future house prices and their implications for boom-bust cycles and monetary policy. Our findings are as follows. First, waves of optimism and pessimism about future house prices generate boom-bust cycles in house prices, financial activities (household debt, business debt, bank leverage, interest rates on household and business loans) and the real economy (housing demand, consumption, employment, investment and output). Second, we find that inflation declines during a house price boom and increases during a house price burst. Third, we find that monetary policy that reacts to household credit growth reduces the magnitude of boom-bust cycles and improves household welfare. Fourth, we find that the case for taking into account household credit growth becomes stronger in an economy in which the bank capital to asset ratio requirement is low, interest rates on loans and deposits adjust immediately to changes in the policy rate, or the household sector is highly indebted. / Essay 3: Credit Disruptions and the Spillover Effects between the Household and Business Sectors This essay examines the effects of credit supply disruptions in a New Keynesian DSGE model with housing collateral and working capital channels. A tightening of business credit conditions creates negative spillovers from the business sector to the household sector through labor income and housing collateral channels. A tightening of household credit conditions has negative spillover effects on the business sector via the housing collateral channel. We find that spillovers are more sensitive to changes in leverage where the shock occurs. A negative business credit shock creates upward pressure on inflation, whereas a negative household credit shock creates downward pressure on inflation. The working capital channel magnifies the response of inflation to a business credit shock, whereas it dampens the response of inflation to a household credit shock.

Perturbações na malha aérea ocorrem em todo o mundo e afetam econômica e operacionalmente as empresas aéreas. Em 2016, os gastos que essas perturbações causaram às empresas aéreas e aos seus clientes giraram em torno de US$60 bilhões, cerca de 8% da receita de todas as empresas aéreas do mundo. Este trabalho apresenta uma Heurística Matemática Híbrida, envolvendo otimização por programação inteira mista, para resolver o Problema da Recuperação da Malha Aérea de uma empresa, em até vinte minutos, para uso do Centro de Controle Operacional (CCO) da empresa aérea. A solução consiste em uma nova programação de voos que minimiza os custos da alteração da malha aérea e atenda as restrições impostas por um cenário de múltiplas perturbações, quais sejam: atrasos, cancelamentos de voos, fechamento ou redução de capacidade aeroportuária e manutenções não-programadas. Além da heurística, apresenta-se também um modelo de fluxo em rede com programação inteira para resolver de forma exata o Problema da Recuperação da Malha. Esse modelo obteve resultados em instância de até 500 voos, para todo tipo perturbação, em tempo de execução razoável, exceto para as instâncias em que a capacidade aeroportuária estava muito comprometida. A heurística matemática híbrida apresentou resultados com diferenças de até 5% com relação ao ótimo para as instâncias com até 6000 voos, independentemente do nível de perturbação imposta à malha aérea, com tempo de execução que permite o seu uso prático. / Schedule disruptions occurs worldwide and affect economically and operationally the airlines. In 2016, disruptions cost airlines and their customers around $60 billion, or about 8% of worldwide airline revenue. In this thesis, a Hybrid Math-Heuristic including a mixed-integer linear optimization is presented. It is aimed at assisting airlines to solve the Aircraft Recovery Problem through their Operations Control Centers (OCC) in up to twenty minutes. The solution consists in a new changed schedule that minimizes the cost of changes and deals with constraints related to a scenario with multiple disruptions: delays, flight cancelations, closures or airport capacity reduction and non-scheduled maintenance. Besides the heuristic, a network flow integer programming model is presented to provide exact solutions to the Aircraft Recovery Problem. The Exact Model achieved optimal results for instances with up to 500 flights subjected to all kinds of disruptions in reasonably times, except for instances with highly constrained airport capacity. The Hybrid Math-Heuristic achieved results with maximum optimal GAP of up to 5% for instances with up to 6.000 flights, no matter the level of the imposed disruption, with time of execution that permits its use in practice.

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The study of network-service disruptions caused by large-scale disturbances has mainly focused on assessing network damage; however, network-disruption responses, i.e., how the disruptions occur depending on social organizations, weather, and power resources, have been studied little. The goal of this research is to study the responses of network-service disruptions caused by large-scale disturbances with respect to (1) temporal and logical network, and (2) external factors such as weather and power resources, using real and publicly available heterogeneous data that are composed of network measurements, user inputs, organizations, geographic locations, weather, and power outage reports. Network-service disruptions at the subnet level caused by Hurricanes Katrina in 2005 and Ike in 2008 are used as the case studies. The analysis of network-disruption responses with respect to temporal and logical network shows that subnets became unreachable dependently within organization, cross organization, and cross autonomous system. Thus, temporal dependence also illustrates the characteristics of logical dependence. In addition, subnet unreachability is analyzed with respect to the external factors. It is found that subnet unreachability and the storm are weakly correlated. The weak correlation motivates us to search for root causes and discover that the majority of subnet unreachability reportedly occurred because of power outages or lack of power generators. Using the power outage data, it is found that subnet unreachability and power outages are strongly correlated.

The climate and ecological emergency (CEE) is depicted as far in space and time to the (yet) unaffected human through politics not acting according to it as well as media not doing the topic justice. No experiences or experiences only through media depiction are created which the human bases its reality on. This is not only problematic but also mediates a distorted reality of not being and feeling affected by the CEE. (Climate) activism can be seen as a counter-perspective of politics. Extinction Rebellion (XR) – a decentralized movement – mostly aims for polarization, actions in the physical space, and disruptions. Decentral XR groups practice close-making of the CEE through different strategies and affect-mediations in the public space. Nevertheless, like most climate activist actions, it also deals with the dilemma of media depictions. The reach of the action within the public space as an affect-mediation is lesser than the reach through the media translation. If most humans are negatively affected through the media reach, what happens if affect-mediations are executed in the coded infrastructure(s) that surrounds the humans? As human entanglements with the coded infrastructure(s) can be seen as a body-mind-life extension, I aim with this work to intervene in it. By proposing to seed digitally induced disruptions as affect-mediations in the human entanglements with coded infrastructures(s) surrounding them, the work is aiming to practice close-making and enhance the notion of feeling affected. The approach was explored by mapping out the coded infrastructure(s) of the author, making it public through two workshops as well as setting up affect-mediation prototypes. By empowering local (XR) activist groups to explore and generate disruptive ideas based on my proposal, the research question emerged: How can local activist (Extinction Rebellion) groups be empowered to create affect-mediations and therefore affecting bodily experiences with the CEE through executing digitally induced disruptions to support their local demands? While conceptualizing a platform for XR as the Design Project – incorporating and digitally translating the workshop as well as other elements – the concept aims to host a collective pool of digitally induced disruption actions and approaches.

The invasion of Ukraine during early 2022 resulted in significant disruptions for supply chains globally. With massive delays and resource shortages, many companies have found a need to rethink their approach to resilience to not be as affected by future disruptions of similar proportions. These companies did not have much time to prepare for the Ukraine conflict as the effects of the disruptions caused by the Covid19 pandemic could still be felt. In the midst of these disruptions there is also a large ongoing shift toward more sustainable practices that aim to reduce waste and streamline operations. Balancing between these sustainable practices and efficient resilience measures is a difficult task as there are many ways the two can clash. Through a case study on the Swedish automotive industry the disruptions caused by the Covid pandemic and Ukraine conflict were looked into as well as what resilience measures were being implemented in response. The effects that both the disruptions and resilience measures had on the sustainable practices of the companies were explored in addition. The study collected data through semi-structured interviews to gather first-hand insights into the relevant supply chains. Based on the conducted research, the study presents three primary findings. Firstly, there is a rising trend in the Swedish automotive industry to rethink current resilience strategies and become more proactive. This is new as the previous approach has been primarily reliant on reactive resilience measures. The first step in this transition focuses on supply chain mapping and visualization to become more knowledgeable about one's supply chain. With the newfound information, the companies are planning to put in efforts where they are most effective with measures like dual sourcing and buffer stocks are critical points in the chain. Secondly, the study presents a transition towards local supply chains as a means to connect resilience and sustainability for enhanced benefits to both areas. With shorter transport routes, there is less risk for disruptions and lower emissions. Moving sourcing to Europe also enables better transparency and promises better working conditions as a result of local labor laws. Local sourcing further provides stability by minimizing the effects disrupting events in other parts of the world have on the supply chain. Thirdly, the concept of product redesign is presented as an alternative resilience measure. When supply of materials becomes scarce and bottlenecks arise, adapting products to what is available can offer flexible companies with a new reactive measure of resilience. This measure offers a unique way of optimizing resource usage while minimizing the impact of a disruption. As companies become more aware of potential future disruptions, the redesign of products based on perceived future availability of materials can also serve as a proactive resilience measure. / Invasionen av Ukraina våren 2022 resulterade i betydande störningar för värdekedjor globalt. Med storskaliga förseningar och resursbrist var många företag tvungna att tänka om deras inställning till resiliens för att inte bli påverkade i samma utsträckning av framtida störningar av samma storlek. Dessa företag hade inte mycket tid till att förbereda sig för Ukrainakonfliktens effekter eftersom Covidpandemins påverkan fortfarande kändes. Samtidigt som detta sker pågår även en stor omställning till mer hållbara metoder med minskat avfall och optimerade verksamheter som mål. Balansen mellan hållbarhet och resiliens är svår att hitta då det finns många sätt de två kan krocka. Genom en fallstudie på den svenska fordonsindustrin studerades störningarna som Covidpandemin och Ukrainakonflikten gett upphov till samt de resiliensåtgärder som implementerades som svar. Utöver det utforskades effekterna av så väl störningarna som resiliensåtgärderna hade på företagens hållbarhetsarbete. Studien samlade in data genom intervjuer för att få förstahandsinformation om de relevanta värdekedjorna. Baserat på studien kunde tre slutsatser presteras. För det första, det finns en stigande trend inom den svenska fordonsindustrin att tänka om nuvarande resiliensstrategier för att bli mer proaktiva. Detta är nytt då det tidigare hållningssättet var att främst förlita sig på reaktiva resiliensåtgärder. Det första steget i denna omställning fokuserar på att kartlägga och visualisera värdekedjan för att få mer kännedom om den. Med den nyfunna kunskapen planerar företag att agera där det får störst effekt med åtgärder såsom utökad lagerhållning och utökning med alternativa leverantörer. För det andra, studien presenterar en övergång till mer lokala värdekedjor som ett sätt att binda samman resiliens och hållbarhet för stärkt effekt inom båda områdena. Med kortare transportsträckor finns en lägre risk för störningar och även lägre utsläpp. En övergång till försörjning av europeiska varor möjliggör bättre transparens och arbetsförhållanden till följd av lokala lagar. Lokala inköp bidrar till ytterligare stabilitet genom att minimera effekterna störningar i andra delar av världen har på den egna värdekedjan. För det tredje, omdesign av produkter presenteras som ett koncept för en alternativ resiliensåtgärd. När tillgång till material sinar och flaskhalsar uppstår kan flexibla företag genom att anpassa sina produkter till vad som finns tillgängligt finna en reaktiv resiliensåtgärd. Denna metod erbjuder ett unikt sätt att optimera resursanvändningen samtidigt som störningens effekt minimeras. Allt som företag blir mer medvetna om potentiella framtida störningar kan omdesign av produkter baserat på uppskattad framtida tillgänglighet av material utgöra en proaktiv resiliensåtgärd.

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Yes / Purpose Medicine shortages have a detrimental impact on stakeholders in the pharmaceutical supply chain (PSC). Existing studies suggest that building resilience strategies can mitigate the effects of these shortages. As such, this research aims to examine whether resilience strategies can reduce the impact of medicine shortages in the United Kingdom's (UK) PSC. Design/methodology/approach A sequential mixed-methods approach that involved qualitative and quantitative research enquiry was employed in this study. The data were collected using semi-structured interviews with 23 key UK PSC actors at the qualitative stage. During the quantitative phase, 106 respondents completed the survey questionnaires. The data were analysed using partial least square-structural equation modelling (PLS-SEM). Findings The results revealed that reactive and proactive elements of resilience strategies helped tackle medicine shortages. Reactive strategies increased relational issues such as behavioural uncertainty, whilst proactive strategies mitigated them. Practical implications The findings suggest that PSC managers and decision-makers can benefit from adopting structural flexibility and proactive strategies, which are cost-effective measures to tackle medicine shortages. Also engaging in strategic alliances as a proactive strategy mitigates relational issues that may arise in a complex supply chain (SC). Originality/value This study is the first to provide empirical evidence of the impact of resilience strategies in mitigating medicine shortages in the UK's PSC.

O consumo de drogas resulta em consequências para o indivíduo tanto no âmbito social quanto no de saúde. Conhecimentos sobre comportamentos de saúde dos usuários de drogas tornam-se relevante para melhor compreender esse grupo. O estudo teve por objetivo avaliar as propriedades psicométricas do Questionário Comportamentos de Saúde em usuários de substâncias psicoativas. Trata-se de um estudo quantitativo do tipo descritivo. O estudo foi desenvolvido no Centro de Atenção Psicossocial - Álcool e Drogas de Ribeirão Preto, SP, Brasil. A amostra foi composta por 140 usuários do serviço. O instrumento utilizado foi composto por: Informações sociodemográficas, Escala de Severidade da Dependência de Drogas, Severity Alcohol Dependence Data e o Questionário Comportamentos de Saúde. Utilizou-se a análise descritiva dos dados e a validade de construto por meio da análise fatorial. Para a consistência interna do instrumento e de seus fatores utilizou-se o coeficiente alfa de Cronbach. A amostra caracteriza-se predominantemente por usuários do sexo masculino, adultos, solteiros, cor da pele branca, com baixo nível de escolaridade. A maior parte deles já esteve em tratamento e a busca por atendimento ocorreu voluntariamente ou por meio de seus familiares. A droga de maior consumo foi o crack. Os usuários, em sua maioria apresentaram níveis graves de severidade da dependência alcoólica e também da dependência de cocaína e crack. A maconha foi a droga de primeiro uso. A análise fatorial resultou em um modelo composto por oito fatores, sendo: comportamentos sexuais seguros; autocuidado com poluição ambiental; saúde; atividades físicas; autocuidado com alimentação; alimentação saudável; automedicação e consumo de bebidas alcoólicas, além da segurança motorizada. Os coeficientes de alfa de Cronbach mostraram-se satisfatórios com índices acima de 0,50 para os fatores, e 0,82 para o questionário Comportamentos de Saúde global. Os resultados confirmam a confiabilidade do Questionário Comportamentos de Saúde na versão brasileira para sua aplicabilidade em usuários de substâncias psicoativas. / Drugs consumption results in consequences for the individual both in the social as in health environment. Knowledge about health behaviors of drug users becomes important to better understand this group. The study aimed to evaluate the pschycometric propriety of the health behavior questionnaires in users of psychoactive substances. It is about a quantitative descriptive study. The study was conducted at the Center of Psychosocial Care - Alcohol and Drugs from Ribeirão Preto, SP, Brazil. The sample consisted of 140 service users. The instrument used was composed of: Sociodemographic Information, Severity of Dependence Scale, Severity Alcohol Dependence Data and the Health Behaviors Questionnaire. It has been used a descriptive analyses of the data and construct validity using factor analysis. For the internal consistency of the instrument and it\'s factors it was used the Cronbach Alpha Coefficient. The sample is characterized predominantly by male users, adults, singles, white color (Caucasian) with a low educational level. Most of them have already been on treatment and the search for it happened voluntarily or through their families. The most consumed drug was crack. The majority of users presented serious levels of severity of alcohol dependence and also the dependence of cocaine and crack. Cannabis was the first used drug. Factor analysis resulted in a model composed of eight factors, as follows: safe sexual behavior; self care with environmental pollution; health; physical activity; self care with food; healthy eating; self medication and alcohol consumption, as well as motorized safety. The Cronbach\'s alpha coefficients were satisfactory with indexes above 0.50 for the factors, and 0.82for the global Health Behaviors Questionnaire. The results confirm the reliability of the Health Behaviors Questionnaire in Brazilian version forits applicability in users of psychoactive substances.

Com a heterogeneidade de tecnologias de comunicação sem fio presentes na borda de redes de acesso, serviços providos na Internet podem ser acessados de forma quasi ubíqua através de dispositivos móveis ou portáteis. O acesso a esses serviços, contudo, está associado a atrasos e rupturas frequentes na comunicação devido a razões inerentes à mobilidade do dispositivo, como: i) perda de sinal em locais onde há pouca ou nenhuma cobertura de acesso móvel; ii) erros no quadro de dados durante a transmissão e, consequentemente, perdas de pacotes, que podem ser ocasionados por interferência no sinal ou enfraquecimento deste pelo distanciamento do dispositivo em relação à Estação Base; iii) mudanças de endereços IP durante transmissões em andamento causadas pela migração do dispositivo entre diferentes redes. Como consequência, aplicações falham com a ruptura de comunicações orientadas a conexão. Tratar a mobilidade de forma transparente à aplicação é um dos desafios da Computação Móvel e Ubíqua que vem sendo pesquisado ao longo da última década. Soluções foram propostas para operarem desde a Camada de Enlace à Aplicação. Muitas delas, entretanto, exigem modificações na pilha de protocolos TCP/IP e adição de infraestrutura específica de rede no suporte à comunicação fim-a-fim. Além de elevar o custo das etapas de implantação e manutenção, estratégias intrusivas e dependentes de infraestrutura adicional podem não apresentar desempenho satisfatório. Nesse contexto, propomos tratar a mobilidade no nível da própria aplicação através de Sessões de Comunicação que não falham com atrasos e desconexões. Operando somente nos nós-fim e de modo transparente às Camadas adjacentes de Aplicação e Transporte, as sessões não requerem infraestrutura adicional para intermediar ou controlar a comunicação entre pares, tampouco modificações em protocolos legados da pilha TCP/IP. O conceito de Sessões Tolerantes a Rupturas é implementado através de uma API de propósito geral em sistemas Linux que estende a interface de Sockets. A API é, na prática, uma camada transparente sobre o Socket que provê Ciência de Mobilidade à aplicação através de mecanismos para: acompanhar a localização de nós ao longo da duração de uma sessão; detectar rupturas nas transmissões causadas pela mobilidade do nó ou de seu par remoto; suspender e retomar sessões de forma eficiente, segura e confiável. Experimentos conduzidos em ambientes emulados e reais com equipamentos de uso comercial mostram a eficiência das sessões. Além de introduzir baixa degradação na vazão fim-a-fim, rupturas na transmissão podem ser detectadas em microssegundos e sessões suspensas são reabertas em milissegundos. Com um desempenho superior a solução de mobilidade geral da Camada IP, as sessões não necessitam de adaptações de software em equipamentos de rede / Nowadays services available on the Internet can be accessed from mobile devices while they roam across heterogeneous wireless networks. Due to the inherent reasons of device mobility, however, the access to such services is frequently involved with delay and disruptions. The most common reasons are: i) losing radio signal at places where mobile access coverage area is not available; ii) frame error, losses, and fading on the radio signal when the mobile device moves away from the Base Station; iii) changes on the devices IP address over ongoing transmission, while the mobile node migrates among different wireless networks. As result, networked application fails with disruptions on TCP connections established in the mobile users path. Handling seamlessly mobility on the Internet is a technical challenge of the Mobile Computing Paradigm. It has been widely researched over the last decade. Several solutions have been proposed to work from the Link Layer to the Application Layer. Most of them, however, work intrusively and require modifications in the classical TCP/IP protocol stack, as well as rely on additional network infrastructure to support mobile end-to-end communication. Besides increasing the cost of deployment and maintenance, intrusive and infrastructure dependent strategies may not present suitable performance. In this sense, we devised an architecture to handle mobility at the Application level by means of communication sessions that do not fail with delay, disruption or disconnection. Such sessions work only at the end-systems in a such way that: are fully transparent to the adjacent layers of Transport and Application; do not require additional network infrastructure to forward and manage the communication between two mobile peers; and do not impose any modification on the legacy protocols from the TCP/IP stack. The concept of Disruption-Tolerant Sessions is implemented in Linux by means of a general purpose API extended from the Socket interface. Such API is a transparent layer placed on top of the Socket to provide mobility awareness to the Application Layer. To do so, session services are provided for: tracking mobile peers along the session duration; detecting disruptions over TCP connection caused by mobility of the local or remote peer; suspending and resuming sessions with efficiency, security and reliability. Experiments conducted in emulated and real systems (off-the-shelf hardware and open source software) showed the desired efficiency. Besides introducing little overhead on the goodput, disruptions are detected in a range of microseconds and suspended sessions are resumed in milliseconds. With performance greater than the general IP layer mobility solution, the proposed sessions do not require software adaptation in the core of the network infrastructure