High speed rail transport valuation

The present paper investigates the optimal timing of investment for a high speed rail (HSR) project, in an uncertain environment, using a real options analysis (ROA) framework. It develops a continuous time framework with stochastic demand that allows for the determination of the optimal timing of investment and the value of the option to defer in the overall valuation of the project. The modelling approach used is based on the differential utility provided to railway users by the HSR service.info:eu-repo/semantics/publishedVersio

High speed rail transport valuation and policy decisions

The present paper investigates the process of decision making regarding the optimal timing to invest in the high speed rail (HSR) project, under uncertainty, using the real options analysis (ROA) framework. It’s developed a continuous time framework that allows a solution to the problem concerning the optimal timing to invest and to value the impact of the option to defer in the overall valuation of the project, with multiple uncertainty factors. Besides considering a stochastic demand, the effect of uncertainty in the investment’s expenditure and over the benefit per user is incorporated in a model with three stochastic variables. The modelling approach used is based on the differential utility provided to railway users by the HSR service.info:eu-repo/semantics/publishedVersio

Some general results about the optimal timing of relocation

In this paper we derive general results concerning the optimal switching level in the problem of the optimal relocation policy for a firm that faces two types of uncertainty: one about the moments in which new (and more efficient) sites will become available; and the other regarding the degree of efficiency improvement inherent to each one of these new, yet to be known, potential location places. In particular, we note that the optimal switching level depends on the distribution of the degree of efficiency improvement only through an expected value. Impacts on the final results driven by the characteristics of the firm’s original location site, the market environment and the way in which risk is modelled are studied numerically. The overall results are in line with economic intuition.info:eu-repo/semantics/publishedVersio

High speed rail transport valuation

The present paper investigates the optimal timing of investment for a high speed rail (HSR) project, in an uncertain environment, using a real options analysis (ROA) framework. It develops a continuous time framework with stochastic demand that allows for the determination of the optimal timing of investment and the value of the option to defer in the overall valuation of the project. The modelling approach used is based on the differential utility provided to railway users by the HSR service.info:eu-repo/semantics/publishedVersio

Cálculo de ciclos de trabalho em sistemas automáticos de armazenamento.

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 201

Digital transformation in Portuguese shadow education : the tutor perspective

Often metaphorically called “shadow education”, the global private tutoring market was estimated to be valued at 146,1 billion dollars in 2022, making it a significant contributor to the economy. Despite this, there is a clear lack of literature on this topic. The COVID-19 pandemic and resulting lockdowns had a profound impact on society. Tutors were forced to adapt and provide online tutoring which accelerated digital transformation in this sector. However, it is still unclear what is happening post-pandemic, particularly in Portugal, where the government ignores this sector, and the literature is scarce. This study, therefore, aims to investigate the impact of COVID-19 on the digital transformation of shadow education operations in Portugal, as well as its future implications. To better understand the problem at hand, a literature review was conducted, followed by a qualitative approach with 51 in-depth interviews with tutors providing tutoring services to secondary education students (nomenclature defined by UNESCO that includes “Ensino básico” and “Ensino secundário”). The findings demonstrate that COVID-19 accelerated the digital transformation in the shadow education sector in Portugal due to the forced adoption of online tutoring which required the use of new programs and software. Most of the tutors interviewed regard the digital transformation induced by COVID-19 as an ongoing process, with its impact limited by the negative performance of the schooling system during the lockdown period.Muitas vezes denominado metaforicamente de “educação sombra”, o mercado global de explicações privadas foi avaliado em 146,1 mil milhões de dólares em 2022, tendo uma contribuição significativa para a economia. Apesar disso, verifica-se uma clara falta de estudos académicos sobre este assunto. A pandemia de COVID-19 e os consequentes confinamentos tiveram um profundo impacto na sociedade. Os explicadores foram forçados a se adaptarem e a disponibilizar explicações online, o que acelerou a transformação digital neste setor. Contudo, ainda não é claro o que está a acontecer no período pós pandemia, especialmente em Portugal, onde o governo ignora o setor das explicações e a literatura é escassa. Assim, este estudo foca-se em investigar o impacto que a COVID-19 teve na transformação digital das operações do setor de educação sombra, bem como as futuras implicações. Para entender melhor o problema em questão, foi realizada uma revisão da literatura, seguida de uma abordagem qualitativa com 51 entrevistas a explicadores que prestam serviços de explicação a estudantes do ensino básico e secundário (nomenclatura definida pela UNESCO como “secondary students”). Os resultados obtidos demonstram que a COVID-19 acelerou a transformação digital no setor da educação sombra em Portugal devido à adoção forçada de explicações online, o que exigiu o uso de novos programas e software. A maioria dos explicadores entrevistados viu a transformação digital induzida pela COVID-19 como um processo contínuo, cujo impacto foi limitado pelo desempenho negativo do sistema escolar durante o período de confinamento

Successive interference cancellation in vehicular networks to relieve the negative impact of the hidden node problem

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Telecomunicações). Universidade do Porto. Faculdade de Engenharia. 201

Skin tests and challenge-based drug allergy diagnosis: a retrospective study of patients with confirmed drug allergy

Objectives. To describe clinical manifestations and performed diagnostic workup, focusing drug challenge tests (DCT), in patients with drug allergy. Methods. Retrospective study including all patients with skin tests (STs) or DCT-based drug allergy diagnosis, between 01/2014 - 06/2018 in a Portuguese allergy unit. Data were collected from electronic and paper-based clinical records. Results. We had 75 drug allergy diagnoses. Most index reactions were mild and major or equal 1 hour after drug intake. 59 (78%) diagnoses were based on DCTs, all based on multistep protocols with major or equal 3 predicted steps. Only 10% of the DCT were positive during up-dosing; timing and severity of the index reaction predicted DCT interruption during up-dosing. Conclusions. Most drug allergy diagnoses were based on multistep DCT. The identified predictors of DCT interruption during up-dosing can support the development of more personalized DCTs protocols.info:eu-repo/semantics/publishedVersio

Cold spray deposition of WC-Co

Tese de mestrado integrado. Engenharia Metalúrgica e de Materiais. Universidade do Porto. Faculdade de Engenharia. 201