Pedro Cosme Costa Vieira

• PhD + Diploma
• Inactive at University of Porto

Os reactores nucleares não emitem gases com efeito de estufa mas a gestão dos resíduos radioativos de alto nível permanece um dos maiores desafios da energia nuclear. Apesar de continuar com uma elevada densidade energética, o combustível nuclear usado é tradicionalmente tratado como um passivo a longo prazo, sujeito a armazenamento prolongado e so...

A redução dos custos de recolha, transmissão, armazenamento e processamento da informação tem permitido o crescimento exponencial das bases-de-dados. Neste texto vou apresentar o conceito de Base-de-Dados-Relacional e mostrar exercícios que tornem o leitor capaz de pegar num qualquer problema de gestão de informação e desenhar uma base-de-dados na...

The decreasing costs of information collection, transmission, storage, and processing have enabled the exponential growth of databases. In this text, I will introduce the concept of the Relational Database and present exercises that will enable the reader to take any information management problem and design a database in Third Normal Form.

Nos últimos 50 anos aconteceu uma grande abertura do mercado norte-americano ao comércio internacional o que permitiu ganhos importantes no nível de vida de países como a China e a Índia. No entanto, essa abertura veio acompanhada por um défice da balança corrente que se acumula em cerca de $23E12. Sendo que o presidente Donald Trump entende que es...

Over the past 50 years, the U.S. market has experienced significant liberalization in international trade, which has allowed countries such as China and India to achieve substantial improvements in living standards. However, this liberalization has been accompanied by a persistent current account deficit amounting to a total of approximately $23 tr...

Os sistemas de comunicação à distância usando num canal público são matematicamente seguros quase a 100% se forem usados os algoritmos DH, RSA ou ECDH e confirmadas as chaves públicas. O problema está nas falhas humanas em que, por erro ou descuido, o indivíduo revela a sua chave privada. Foi isso que aconteceu no Signalgate em que o gestor de um g...

Long-distance communication systems using a public channel are mathematically secure almost 100% of the time when using the DH, RSA, or ECDH algorithms, provided public keys are properly confirmed. The main issue lies in human errors, where individuals may inadvertently reveal their private keys. This was the case in the Signalgate incident, where...

Electricity generated from solar power has seen a significant decrease in unit cost but suffers from the issue of requiring a backup system when there is no sunlight, which considerably increases the average cost of energy. In contrast, nuclear-generated electricity seems to be on the path to extinction as its unit cost has increased to the point t...

Resumo: Mais do que a qualidade do ensino, o financiamento das instituições universitárias está cada vez mais ligado ao impacto dos artigos científicos publicados pelo seu staff o que implica que a contratação e promoção dos professores está cada vez mais sub-contratado no factor de impacto das revistas científicas o que desenvolve nestas um poder...

More than the quality of teaching, university funding is increasingly linked to the impact of scientific articles published by its faculty. This implies that the hiring and promotion of professors is becoming increasingly dependent on the impact factor of scientific journals, granting these journals a monopoly power that results in submission, publ...

Cryptocurrencies are trendy but are nothing more than a "Pump and Dump" scam. This paper presents the foundational concepts of a ledger-based currency, of which Bitcoin is an example. As an exercise in monetary information management, crypto-notes once created can be used without control from any authority. The created crypto-notes are superior to...

As cryptomoedas estão na moda mas não são mais do que uma fraude "Pump and Dump". Este texto apresenta os conceitos fundadores de uma moeda escritural de que a bitcoin é um exemplo. Como exercício de gestão de informação monetária são criadas crypto-notas que podem ser usadas sem controlo de nenhuma autoridade. As crypto-notas criadas são superiore...

Actualmente, a capacidade da linha férrea de transporte de passageiros que liga Lisboa a Setúbal e que é explorada pela Fertagus tem capacidade claramente insuficiente para as necessidades. Neste texto, com a ajuda do chatGPT, implemento um modelo de simulação em tempo real da linha férrea com o qual mostro que pode haver a triplicação do número de...

Currently, the railway line connecting Lisbon to Setúbal, operated by Fertagus, has a transport capacity that is clearly insufficient for demand. In this text, with the help of ChatGPT, I implement a real-time simulation model of the railway line, demonstrating that the number of transported passengers can be tripled. The evaluation shows that doub...

Resumo: Apesar de o AES ser um algoritmo de encriptação simétrica impossíveis se quebrar se a chave secreta tiver qualidade e não for comprometida, ao ser patrocinado pela NIST, há quem acredite que os norte-americanos introduziram uma chave mestra, uma backdoor. Para essas pessoas proponho um novo algoritmo de encriptação que é velho no sentido de...

Although AES is a symmetric encryption algorithm that is impossible to break if the secret key is strong and remains uncompromised, its endorsement by NIST has led some to believe that the U.S. government introduced a master key, a backdoor. For those who share this concern, I propose a new encryption algorithm that is old in the sense that the XOR...

Resumo: Neste texto resolvo o problema dos servidores, sem separar os que facultam informação legal dos que facultam informação ilegal, que pretendem manter a confidencialidade mesmo permitindo o acesso anónimo. O algoritmo tem duas fases. Na primeira fase, é criado um sistema de registo que garante a anonimidade dos utilizadores. Na segunda fase,...

In this text, I address the problem of servers-without distinguishing between those providing legal and illegal information-that seek to maintain confidentiality while allowing anonymous access. The algorithm consists of two phases. In the first phase, a registration system is created that ensures user anonymity. In the second phase, a debugging al...

Resumo: Neste texto proponho um Universo infinito, com dimensão infinita, massa infinita e que não teve início nem terá fim. É difícil imaginar esta teoria porque a mente humana não consegue abarcar o infinito. É necessário dar este passo porque a teoria aceite de que o Universo é uma realidade finita que teve início há tempo finito da explosão de...

In this text, I propose an infinite Universe, with infinite dimension, infinite mass, and one that had no beginning and will have no end, infinite time. It is difficult to accept this theory because the human mind cannot grasp infinity. Nonetheless, this step is necessary because the accepted theory that the Universe is a finite reality that began...

Resumo: A inferência Estatística testa se uma hipótese sobre uma população, H0, é compatível com uma amostra com elementos selecionados de forma aleatória. O comum é que H0 seja um escalar que representa o valor médio da população. No entanto, há muitos problemas em que a população é caracterizada por um vetor cujas componentes, por exemplo, quanti...

Abstract: Statistical inference tests whether a hypothesis about a population, H0, is compatible with a sample whose elements are randomly selected. Typically, H0 is a scalar representing the population's average value. However, in many cases, the population is characterized by a vector whose components, for example, quantify the proportion of a ce...

Resumo: Os casinos on-line têm problemas de segurança financeira, de confiança nos resultados e dificuldades no cálculo do pay-off dos jogos por parte dos apostadores o que os obriga a recorrer a uma entidade externa acreditadora. Estes problemas traduzem-se numa barreira à entrada no mercado de novos casinos o que desfavorece os consumidores de jo...

Online casinos face financial security issues, lack of trust in game outcomes, and difficulties for Gamblers in calculating game pay-offs, forcing them to rely on external accreditation entities. These challenges create a barrier to market entry for new casinos, ultimately disadvantaging gambling consumers. In this text, I will develop a protocol t...

Resumo: A desmaterialização dos processos judiciais torna obrigatório que a sua distribuição pelos juízes passe a ser feita remotamente e de forma ágil sem, com isso, colocar em causa a aleatoriedade e a transparência do procedimento. Neste texto vou desenvolver um algoritmo que, transmitindo informação ofuscada entre o Tribunal e o Autor numa fase...

Resumo: Em Junho de 1742 Goldbach conjetura que qualquer número inteiro par pode ser decomposto na soma de dois números primos e, consequentemente, qualquer número inteiro ímpar pode ser decomposto na soma de três números primos. Neste texto não provo nem contraprovo esta conjetura mas apenas conjeturo que, na forma reduzida, o número de conjuntos...

In June 1742, Goldbach conjectured that any even integer can be decomposed into the sum of two prime numbers, and consequently, any odd integer can be decomposed into the sum of three prime numbers. In this text, I neither prove nor disprove this conjecture. Instead, I conjecture that, in its reduced form, the number of sets that decompose an integ...

In this text, I will compare Communism with Capitalism in addressing the economic problem of allocating scarce resources to maximize people's happiness. I demonstrate that, on a national scale, even if Communism is perfectly implemented-that is, with a benevolent dictator-such implementation will inevitably lead to poverty and the loss of individua...

Neste texto vou comparar o Comunismo com o Capitalismo na resolução do problema económico da afectação dos recursos escassos de forma a maximizar a felicidade das pessoas. Mostro que, à escala de um país, mesmo que o comunismo seja implementado de forma perfeita, isto é, com um bom tirano, essa implementação acabará necessariamente em pobreza e per...

Resumo: A programação é uma ferramenta conceptual em que os problemas complexos são divididos em problemas elementares que, depois, são combinados. Criado o programa ou algoritmo, vem a fase da codificação numa linguagem de programação. Vai ser apresentada a Python porque é de fácil aprendizagem e tem uma leitura fácil o que permite a identificação...

We all accept that the probability of an event occurring is always non-negative. The question I pose is: "What if there are events whose probability of occurrence is negative?" Could statisticians be as mistaken as Pythagoras was when he argued that all real numbers could be represented as a ratio of two natural numbers? Perhaps the existence of ne...

Nowadays, discussing Artificial Intelligence means discussing supervised multilayer neural networks solved with groups of thousands of GPUs with astronomical computational capacities. However, the foundation of AI is the simple rule, y(x) = 0 if x < k else 1, which statistically divides data into two subgroups. In this text, I will talk about rules...

Should a quantum computer suddenly emerge, due to Shor’s algorithm, current key exchange algorithms, such as DH, RSA, and ECDH, will become unsafe. In this paper, I present the modular exponentiation of a matrix as a quantum-safe key exchange algorithm, DHMatrix, implementing an efficient algorithm using Python. The DHMatrix is quantum-safe because...

When the Internet was created, due to computational restrictions of network cards publicly visible addressing was necessary, which allows for the collection of metadata and enables certain countries to block specific private servers. For example, Google, WhatsApp, and ChatGPT are blocked in China. My proposal is to use ECDH [1, 2] to encrypt IP add...

The literature on ‘Sleeping Beauties’ (SBs), papers that have been ‘asleep’ for a certain amount of time and that, suddenly, gain a significant amount of attention, is not very extensive, and has analyzed the phenomenon mainly in the Sciences. The present study seeks to find the SBs and their 'Princes’ (first studies citing the SBs that have more c...

The present study focuses on the estimation of the human capital stock for the Cape Verdean economy in the period 1950‐2012. Adapting the methodology proposed by Barro and Lee, based on past schooling values, we found that between 1950 and 2012 the Cape Verdean working-age population showed a gradual improvement in the levels of schooling, rising f...

A Sleeping Beauty (SB) is a publication that goes unnoticed for a long time, and then, almost suddenly, is awakened by a ‘prince’ (PR), attracting from there on a lot of attention in terms of citations. Although there are some studies on the SB and the PR phenomena in the sciences, barely any research on this topic has been conducted in the social...

Varroa destructor is a parasitic of honeybees that, beginning in the 1960´s, has become a worldwide serious economic problem. Although there are miticides capable of controlling the infestation they contaminate the honey. In this paper I question if it is possible to implement a perfectly different strategy that is to isolate the brood area from th...

The rapid growth in the consumption of electricity in China and India has been covered at 80% by coal, which has the side effect of emitting CO2 to the atmosphere. The alternative is the use of nuclear energy that, to become unquestionably competitive, must use super critical water as coolant. The problem is that the inflow temperature of a super c...

20 years after the Maastricht Treaty, the Euro Zone (EZ) is on the brick of disaster because some of the EZ countries higher inflation originated the accumulation of massive external deficits. Now the Euro has been converted in a straitjacket that compels those highly indebted countries (HIC) to decrease nominal prices and wages to control the exte...

We rank universities and colleges using the EconLit database and measuring quality by the number of American Economic Review-equivalent articles published over the ten-year period 1996-2005. We observe that there is some dissimilarity between the sub-fields rankings and that of the general field of Economics, so that the sub-field rankings provide...

We rank universities and colleges and we list the top 100 authors in the sub-field of International Finance using the EconLit database and measuring quality by the number of American Economic Review-equivalent articles published over the ten-year period 1996-2005. We observe that there is some dissimilarity between the ranking of this sub-field and...

Foi prometido que Portugal, ao pertencer à Zona Euro, iria convergir rapidamente com os restantes países da UE e que teria taxas de juro muito baixas. No entanto, uma década de descontrolo económico levaram o país para uma situação de taxas de juro proibitivamente elevadas o que tem um efeito terrível na economia que se traduz em taxas de desempreg...

The text contains an introductory text to financial mathematics.

Neste texto apresento o modelo base da abordagem te�rica denominada por New Macroeconomics aplicando-o � tend�ncia secular, aos ciclos econ�micos e ao crescente endividamento de Portugal. � demonstrado que i) o endividamento crescente prejudica as exporta��es e favorece as importa��es e que, ii) n�o podendo o aumentar para sempre, a correc��o do en...

In this article, I examine whether the academics reward policy must correlate positively with the published number of articles per co-author, number of pages and journals reputation. This is accomplished by estimating a nonlinear model with a panel data from 168 economics journals covered in the ISI-Web of Knowledge database (58 825 articles). The...

This paper relaxes the Motta & Vasconcelos’ (2005) short-term assumption that firms’ capital is fixed. We demonstrate that, contrary to the conclusion of that article, in the best interest of consumers, even when firms have large economies of scale, long-term forward-looking Antitrust Authorities must block firms’ merger plans whenever profits of f...

CETTE THESE A ETE REALISEE POUR REPONDRE A LA QUESTION SUIVANTE : LES INFORMATIONS APPORTEES PAR LES MARCHES A TERME DE COMMODITES ET LES TECHNIQUES DE COUVERTURE QU'ILS PROPOSENT PEUVENTELLES SERVIR A VALORISER UN GISEMENT PETROLIER ET DECIDER DE SA DATE D'EXPLOITATION ? LES TRAVAUX ONT DONC ETE CENTRES SUR LA VALORISATION D'UN BARIL DE PETROLE PO...

No mercado de trabalho, observa-se que os trabalhadores de empresas com elevado risco de fal�ncia t�m sal�rios mais baixos que a m�dia. Aparentemente, esta observa��o � contr�ria ao previsto pela teoria financeira relativamente a agentes racionais e avessos ao risco que prev� que os activos com maior risco apenas s�o preferidos se a sua rentabilida...

One important issue in firms' governance is how to incentives so that activity centres can become more efficient. In this paper, we first introduce an agency contract where the salary of the manager of an activity centre that produces an intermediate product is dependent of its performance. Secondly, we add competition within the organization. This...

Although there is considerable consensus that Finance, Management, and Marketing are ‘science’, some debate remains with regard to whether these three areas comprise autonomous, organized and settled scientific research fields. In this paper we aim to explore this issue by analyzing the occurrence of citations in the top-ranked journals in the area...

Corruption in the public sector erodes tax compliance and leads to higher tax evasion. Moreover, corrupt public officials abuse their public power to extort bribes from the private agents. In both types of interaction with the public sector, the private agents are bound to face uncertainty with respect to their disposable incomes. To analyse effect...

One important issue in firms’ governance is how to create incentives so that activity centres can become more efficient. In this paper, we first introduce an agency contract where the salary of the manager of an activity centre that produces an intermediate product is dependent of its performance. Secondly, we add competition within the organizatio...

As pessoas receiam a energia nuclear por diversas razões. Foi desenvolvida no contexto de uma guerra mundial, é a base da “destruição mútua garantida”, houve o acidente de Chernobyl e é necessário guardar o combustível utilizado durante vários séculos. Mas Portugal não tem recursos energéticos e precisa de energia para se desenvolver sem aumentar a...

Nuclear energy is economic and does not emit CO2 but has two central setbacks. First, it has not been yet implemented an efficient method of disposing the spent fuel. Second, the reactors’ complexity is expensive and turns possible the occurrence of accidents. In this paper, first I propose a very simple, economic and safe boiling heavy-water react...

Sendo que há necessidade de conhecer a qualidade relativa das “revistas internacionais com avaliação” especializadas em economia regional e urbana, na literatura não existe tal listagem. Para colmatar esta lacuna, apresentamos neste trabalho uma hierarquização e uma classificação das 39 revistas cobertas pela base de dados bibliográfica ISI Web of...

In this article, I examine whether the academics reward policy must correlate positively with the number of published articles per co-author, the number of pages and journal reputation. This is accomplished by estimating a non-linear model with a panel data from 168 economics journals covered in the ISI-Web of Knowledge database (58825 articles). T...

Although it is an empirical regularity that in the trade of homogeneous goods there is persistent price dispersion and buyers search for low-priced items, theoretically we find that in market equilibrium, when buyers are optimisers (the neo-classical framework), these regularities do not occur. Summing this undesirable theoretical result to the fac...

On a regular basis the scientific output of academic people has to be evaluated, e.g. to decide tenure. A very important item in this evaluation is the published papers’ quality that tends to be approximated by its impact in the literature. As the measure of this impact requires a long-term analysis, thus it is used as its estimator the journal ave...

In this paper I investigate whether, in market equilibrium, one observes price dispersion and search when buyers intend to acquire several products whose price is unknown and exists a positive search cost. Although that seems fruitful, I prove that in market equilibrium it is not observed neither price dispersion nor search and shops act as if they...

In this paper I intend to model a firm decision of entrance into a profitable fashion market where fashion results from the existence of positive interdependence between buyers utility functions. I conclude theoretically that i) when incumbent firm has an aggressive strategy it sets a marketing limit strategy that do not permit the other firm to en...

Although it is known that there are circumstances where the competitive situation does not promote social welfare maximization, collusion is usually associated with firms’ strategies that decrease welfare. In this paper, using the theoretical framework of the industrial organization, I demonstrate in a model with two sectors that the economic revol...

Este texto � uma primeira parte de um curso de micro-economia pensado em 2 semestres a leccionar num curso de Economia ou Gest�o, escrito em Portugu�s. Tamb�m � indicado a pessoas graduadas em engenharia. Est� dividido em quatro cap�tulos. O primeiro � introdut�rio. O segundo trata da decis�o do consumidor maximizador de uma fun��o de utilidade car...

Ao nível microeconómico alguma evidência sugere que a acumulação de capital humano está associada a taxas de falência empresariais mais elevadas. Ao nível macroeconómico, contudo, a maioria dos estudos sugere uma relação positiva entre acumulação de capital humano e a dinâmica da produtividade. No presente artigo tentamos compatibilizar as evidênci...

It is an empirical fact that low-level income countries manufacture low price commodities, using simple technology, with no investment in Research and Development. This constitutes a poverty trap where it is not advantageous for workers to get further training and poorly educated/trained workers are not productive to the R&D sector. We present a mo...

In this paper I address four questions concerning the quality of scientific economic papers. First, I validate the ex-ante procedure of computing the average impact of economic papers by comparing its results with the expost values. Second, I calibrate an estimator of papers normalised impact. Third, I compute the ranking variability of journals us...

Four issues concerning the quality of scientific economics papers are addressed. First, the ex-ante procedure of computing the average impact of economic papers are validated by comparing its results with the ex post values. Second, an estimator of papers normalized impact is calibrated. Third, the ranking variability of journals is computed using...

It is acknowledged that in the trading of homogeneous goods there is persistent price dispersion. However, it is theoretically derived that if buyers are optimizers there is no price dispersion. This negative result motivates the emergence of alternative paths in the literature that studies price dispersion. In Burdett and Judd's seminal work, buye...

In global markets, the market shares of the two or three biggest firms sum up more than 90 percent and firms do marketing efforts. However, the classical neo-walrasiano theoretical framework only is able to justify these stylized facts with particular firms’ cost structures, being one reason the presumption that there are no information costs. Towa...

It is widely recognised that one of the greatest economic problems facing developed countries is unemployment. An example of this recognition is the recent reports by the OECD ("The OECD Jobs Study", 1994) on unemployment, its causes and possible policies. One issue that is closely associated with unemployment in many people's minds is competitiven...

In this work, I present an extension of Kydland and Prescott’s (K&P) model. The extension is to consider that prices and wages are nominal and that economic agents anticipate the probability of occurrence of exogenous shocks. Once calibrated the model, I compute the nominal and real dynamic response to a monetary shock. The results observed are in...

Morgan (1983) guaranteed that VSS dominated both FSS and SSR. But it is difficult to calculate the optimal sample size and the optimal reservation price both without recall and with full recall. As VSS without recall is a simplification of VSS with full recall, we will present on appendix a VB30 program that calculates only the full recall case. As...

While inter-regional costs cause the c losing of regions to trade, firms are locally competitive e ven if they aren't competitive e lsewhere. But t he historical t endency is the opening of markets. My work is a theoretical study of the e volution o f the market structure a nd the competitiveness of the "country" with the decrease of inter-regional...

In a global market, a small family firm can only be competitive if it specialises in a link of the chain of value, buying and selling in the market intermediate goods or services.

Based on empirical evidence of the evolution of the computing capacity of x86 CPU (Computer Processor Unit), this paper provides a new rationale for the persistence of duopolistic positions. Since 1960's computing capacity of x86 CPU increased rapidly but it cut short in 2003. We proved that stagnation is an outcome resulting not from technological...

This textbook supports undergraduate microeconomics students. In Chapter 1, it presents the market as three Laws of Nature: i) that supply function is the result from the decision of the sellers, ii) that demand function is the result from the decisions of buyers; iii) that the market balance the decisions of buyers with that of sellers. This chapt...

In this article I investigate which is the effect that the number of co-authors and pages have in the value of economics articles. I address these questions by estimating numerically a non- linear model with data from the 100 top ranking economics journals covered by the ISI-Web of Knowledge database throughout 1986-1996 (39895 articles). The data...

To overcome market failures society creates common laws that stimulate or penalize individual actions, the enforcement of which depends on the actions of public authorities who may be susceptible to corruption. Thus, a new market emerges where 'influences' are traded. Legislators have incentives to deviate from the goal of efficiency and produce la...

Resumo: Na generalidade dos estudos de controlo de qualidade considerados na li-teratura, é assumido que o "processo de controlo" é efectuado pelo mesmo agente económico responsável pelo "processo de fabrico". No meu trabalho, utilizando pro-gramação dinâmica, formalizo um modelo de mercado competitivo em que é transac-cionado um bem ou serviço car...

Nowadays we depend on equipment that may fail at any moment. But some failures may cause such big damage, e.g. the fall of an aircraft, that it is essential a pre-emptive maintenance strategy. In my work, I present an inter-temporal optimisation model that permits the comparison between the net benefit of a pre-emptive maintenance strategy and a co...

In operation sequencing problems where the rate that the operators execute the tasks is increasing with the workload, for example, it is increasing with the size of the queue, the theory of the chaos foresees that it may occur dynamics that resemble the random behaviour. In this work, that is exploratory, we analyse, in theoretical terms, if such c...