Dynamics in stock return volatility and spillover effects: Does firm size matter?

This dissertation explores the relationship between firm size and equity volatility. Working from a solid ground that indicates the existence of a size effect in Banz (1981) and Reinganum (1981), we test two related topics. At first, whether an asymmetric effect in returns’ volatility is linked to firm size and firm’s industrial sector. Secondly, the existence of spillover effects between large and small market capitalization firms. By comparing different ARCH type models, we find that good and bad news have different impacts on volatility, as the asymmetric specifications outperform the symmetric GARCH model. In addition, our empirical results show that such dynamic is stronger in large-cap firms, but it may vary according to the firm’s sector. This study also signals a strong co-movement between large and small firms, as both display a similar dynamic in volatility and a strong correlation, especially in periods of financial turmoil. Using multivariate GARCH models, we end up unveiling an asymmetric behaviour not only in volatility but also in conditional correlation. All ARCH type models are employed to the returns’ volatility of S&P500 Index, Russel 2000 Index, and their respective industry sectors over the 2006-2020 period.Esta dissertação investiga a relação entre a dimensão de uma empresa e a volatilidade das ações. Partindo de uma base sólida de conhecimentos que indicam a existência de um fator dimensão em Banz (1981) e Reinganum (1981), testamos dois temas conexos. Inicialmente, se a assimetria na volatilidade das rendibilidades está associada ao tamanho da empresa e ao setor em que opera. Posteriormente, a existência de efeitos de repercussão entre empresas com elevado e baixo valor de mercado. Ao comparar diferentes modelos ARCH, descobrimos que boas e más notícias geram impactos distintos na volatilidade, já que as especificações assimétricas são superiores ao modelo GARCH simétrico. Os resultados mostram ainda que esta dinâmica é mais significativa em grandes empresas, mas que pode variar conforme o setor. Este estudo revela também um elevado co-movimento entre grandes e pequenas empresas, já que ambas demonstram dinâmicas similares na volatilidade e uma forte correlação, especialmente em períodos de forte instabilidade financeira. Desta forma, através de um GARCH multivariado, acabamos por confirmar um comportamento assimétrico não só na volatilidade, mas também na correlação. Os modelos ARCH implementados modelam a volatilidade dos retornos do índice S&P500, do índice Russel 2000 e dos respetivos sectores para o período 2006-2020

Equity valuation of EDP Renováveis, S.A: A critical assessment of the strategic update 2021-2025

This dissertation valuates EDP Renováveis (EDPR), a subsidiary company from Energias de Portugal (EDP), a vertically integrated energy company, listed on PSI-20. Created in 2007 to maintain and operate the growing renewable energy assets of EDP, EDPR has been the driving force behind the group´s strategic objective of decarbonising the business and being entirely carbon neutral by 2030. A rigorous and well-designed valuation of EDPR is becoming increasingly prominent since EDPR is at the international forefront of the energy transition, has been exhibiting an outstanding financial and operational development over the last years, and can provide price stability to the actual disturbance on global energy prices, mostly caused by the Russia´s aggression against Ukraine, as well as promote global energy independence. Incorporating the assumptions implied in the Strategic Update 2021-2025 issued by the entity, the value of the evaluation points to an enterprise value of €28,629.47, with a price per share of €28,71. The evaluation by multiples has served in the background as a complement to the finding provided by the DCF valuation, by concluding that the investor expectations are increasing, to what concerns the growth of EDPR in the renewable energy market. To finalize, combining both the technical analysis undertaken, and the beliefs regarding the renewable energy industry in the upcoming years, it is possible to state that EDPR represents a decent mid/long term investment opportunity and thus, the purchase of the stock is recommended.Esta dissertação tem por base avaliar financeiramente a EDP Renováveis (EDPR), uma empresa subsidiária da Energias de Portugal (EDP), uma empresa de energia verticalmente integrada, cotada no PSI-20. Criada em 2007 para manter e operar os crescentes ativos de energia renovável da EDP, a EDPR tem sido a força motriz por detrás do objetivo estratégico do grupo de descarbonizar o negócio e ser totalmente neutro em carbono até 2030. Uma avaliação rigorosa e bem concebida da EDPR está a tornar-se cada vez mais proeminente, uma vez que a EDPR está na vanguarda internacional da transição energética, tem demonstrado um desenvolvimento financeiro e operacional notável ao longo dos últimos anos, e pode proporcionar estabilidade de preços à perturbação atual dos preços globais da energia, causada principalmente pela agressão da Rússia contra a Ucrânia, bem como promover a independência energética global. Incorporando os pressupostos implícitos na Atualização Estratégica 2021-2025 emitida pela entidade, o valor da avaliação aponta para um valor de empresa de €28,629.47, com um preço por ação de €28,71. A avaliação por múltiplos serviu, no pano de fundo, como complemento ao finding fornecido pela avaliação do DCF, concluindo que as expectativas dos investidores estão a aumentar, no que diz respeito ao crescimento da EDPR no mercado das energias renováveis. Para finalizar, combinando tanto a análise técnica realizada, como as crenças relativas à indústria das energias renováveis nos próximos anos, é possível afirmar que a EDPR representa uma oportunidade de investimento decente a médio/longo prazo, pelo que se recomenda a compra das ações

The Impact of Online Social Networks on Decision Support Systems

It is commonly accepted that online social networking and decision support systems are two intertwined research field. However, as the extent of such interconnection is still quite scarce, we underwent a large study of these research fields, over a time-span of eight years (from 2003 until 2010). Previous research on this matter had already determined that many concepts are encompassed by both online social networking and decision support systems research. Due to the large number of concepts and using clustering techniques, we were able to determine four concept clusters, namely: the technical infrastructure, online communities, network analysis and knowledge management. After determining the referred concept clusters, we intended to gain further knowledge on how those concepts influenced DSS related research, specifically in terms of their actual support of the three traditional decision-making phases, namely the intelligence, design and choice phases. Not only had we wanted to determine the actual contribution of each cluster to the support of the phases of decision-making process, but also we wanted to perceive the interconnections among the concept clusters themselves, for which we used structural equation modeling techniques. The results presented in this paper evidence that not only online social networks are being used as a technical infrastructure to support the three decision making phases and to support knowledge management and online communities, but also that the other clusters only regard the intelligence phase of the decision process

Monkeypox mysteries of the new outbreak in non-endemic areas

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Monkeypox virus (MPXV) was declared by the World Health Organization (WHO) in mid-2022 to be a public health emergency of international concern, following its spread around the world after circulating in Western and Central Africa. This new outbreak is concentrated in men who have sex with men (MSM). Moreover, beyond the epidemiological change, compared with endemic countries, differences in clinical features and many other aspects have also been detected. These and other characteristics are unusual and still unclear. Based on the available data, the authors try to help to clarify some of the current major gaps in monkeypox knowledge to strengthen the outbreak response.The writing of this manuscript received the support of Fundação para a Ciência e a Tecnologia, grant number UIDB/04295/2020 and UIDP/04295/2020.info:eu-repo/semantics/publishedVersio

JOBBID : a new online talent platform for the Portuguese market : assessing the interest of companies and candidates

The high unemployment levels, particularly on younger segments of the population, have become a pressing matter for the negative economic and social impact they are having in Portugal. With the growth of Internet adoption, as well as the positive impact online talent platforms can have over this issue, the aim of this dissertation is to understand the acceptance of both companies and candidates of a new recruitment/job search solution under the former category. The solution proposed here, JOBBID, is an online talent platform that works as an auction marketplace, where companies bid for a list of curated candidates that fit a certain job position. The platform addresses both students and professionals, focusing on the age range between 18-34, and its primary value proposition is to match the candidate with the job offer in the most efficient way. Starting with an extensive review of literature it was possible to obtain the underlying knowledge to both legitimate and conceptualize the platform. In order to validate this new solution an online survey was built for companies and candidates. Thereafter the results were analyzed. An adapted version of the Technology Acceptance Model of Davis (1989) was used to build a model for online talent platforms and the Intention to Use of the new solution was measured accordingly, when applicable. Moreover, a number of other topics, directly and indirectly, related with the platform were analyzed.Os elevados níveis de desemprego, particularmente nos segmentos mais jovens da população, são um tópico premente pelas consequências económicas e sociais negativas que estão a ter em Portugal. Com o aumento da adopção da Internet, bem como o impacto positivo que as plataformas de talento online podem ter sobre esta questão, o objectivo desta dissertação passa por compreender a aceitação por parte das empresas e candidatos de uma nova solução de recrutamento/procura-de-trabalho incluída na categoria anterior. A solução proposta, JOBBID, é uma plataforma de talento online que funciona como um marketplace de leilões, onde as empresas fazem ofertas a uma lista de candidatos pré-seleccionados cujo perfil corresponde a uma oferta de trabalho. A plataforma está direccionada para estudantes e profissionais, focada num intervalo de idades entre os 18-34, e a sua proposta de valor passa por garantir, de forma eficiente, que o perfil de um candidato corresponda a uma determinada oferta de trabalho. Começando por uma extensa revisão de literatura foi possível obter o conhecimento subjacente para legitimar e conceber a plataforma. De forma a validar esta nova solução foi construído um questionário online dirigido às empresas e candidatos. Subsequentemente os resultados foram analisados. Uma versão adapatda do Modelo de Aceitação de Tecnologia de Davis (1989) foi utilizada para construir um modelo para plataformas de talento online e a Intenção de Uso da nova solução foi medida consequentemente, quando aplicável. Adicionalmente, outros tópicos, directa e indirectamente, relacionados com a plataforma foram analisados

Using GSS For Decision Reconstruction: A Preliminary Study

The importance of understanding the reasons of past decisions is not a new subject. However, there seems to be a gap regarding the verification of the efficiency of tools for understanding past decisions. In this paper we posit that the ability to perform decision reconstruction, using a GSS solution, can provide a flexible solution to the problem, but only if the information model underneath it is able to support/structure both ways the phases of a decision-making process. Based on earlier work, we present a first proposal for a general information model to support the decision-making process, as well as the decision reconstruction process. We tested these ideas by setting a case study where we used a prototype, based on a proposed model, to analyze a simulated public contracting process and present a discussion based on the obtained results

The missing link : theoretical reflections on decision reconstruction

In this paper, we address theoretical considerations on the problem of decision reconstruction, which is defined as the process that allows an individual or group of individuals, whether internal or external to the organization, to understand how a group, using a GSS, reached a previous decision. We also analyze the implications of decision reconstruction with regard to both group support systems (GSS) research and knowledge management We present an information model, whose constituting elements are not only concerned with GSS decision-making, but also towards GSS decision reconstruction. Using a GSS prototype based on the proposed model, we made a preliminary test in order to analyze how different people act when reconstructing decisions. In the process, we have exposed and detected limitations and present a solution proposal to overcome these limitations

Monkeypox: From A Neglected Tropical Disease to a Public Health Threat

Since the first case of human monkeypox was diagnosed in 1970, the disease remained endemic in several countries in West and Central Africa. In 1996, there was a sudden increase in cases in the Democratic Republic of Congo (DRC), and since 2017 an ongoing outbreak in Nigeria took place, probably related to the population growth, human invasion of MPXV animal habitat reservoirs, and the waning of the cross-protection offered from smallpox immunization, later ending in 1980. Since May 2022, an unprecedented outbreak of human monkeypox has rapidly spread around the world, outside endemic regions of Africa, through new modes of transmission, showing differences in clinical features compared with previous reports. The 2022 MPXV strain belongs to the clade of West Africa but diverges from the original strain, making the virus more transmissible. The authors review the main milestones in more than 50 years of history of human monkeypox, from a rare viral zoonotic infection to a public health emergency.The writing of this manuscript received the support of Fundação para a Ciência e a Tecnologia, grant numbers UIDB/04295/2020 and UIDP/04295/2020.info:eu-repo/semantics/publishedVersio

OMECO: Generating personalized business card designs from images

Rising competition in the retail and hospitality sectors, especially in densely populated and touristic destinations is a growing concern for many business owners, who wish to deliver their brand communication strategy to the target audience. Many of these businesses rely on word-of-mouth marketing, delivering business cards to customers. Furthermore, the lack of a dedicated marketing team and budget for brand image consolidation and design creation often limits the brand expansion capability. The purpose of this study is to propose a novel system prototype that can suggest personalized designs for business cards, based on an existing business card picture. Using perspective transformation, text extraction and colour reduction techniques, we were able to obtain features from the original business card image and generate an alternative design, personalized for the end user. We have successfully been able to generate customized business cards for different business types, with textual information and a custom colour palette matching the original submitted image. All of the system modules were demonstrated to have positive results for the test cases and the proposal answered the main research question. Further research and development is required to adapt the current system to other marketing printouts, such as flyers or posters.O aumento da concorrência nos setores retalhista e hoteleiro, especialmente em destinos e densamente povoados e turísticos, é uma preocupação crescente para muitos empresários, que desejam apresentar a sua estratégia de comunicação de marca ao público-alvo. Muitos destes negócios dependem do marketing boca-a-boca, entregando cartões de visita aos clientes. Além disso, a falta de uma equipa de marketing dedicada e de orçamento para a consolidação da imagem e criação de design limita muitas vezes a capacidade de expansão da marca. O objectivo deste estudo é propor um novo protótipo de sistema que possa sugerir desenhos personalizados para cartões de visita, com base numa imagem de cartão de visita já existente. Utilizando técnicas de transformação de perspectiva, extracção de texto e redução de cor, conseguímos obter características da imagem original do cartão de visita e gerar um desenho alternativo, personalizado para o utilizador final. Conseguímos gerar cartões de visita personalizados para diferentes tipos de negócio, com informação textual e uma palete de cores personalizada que corresponde à imagem original apresentada. Todos os módulos do sistema demonstraram ter resultados positivos para os casos de teste e a proposta respondeu à principal questão de pesquisa. É necessária mais investigação e desenvolvimento para adaptar o sistema atual a outros imprimíveis de marketing, tais como folhetos ou cartazes

A Portuguese Study

A balanced implementation of functionalities within a commercial internet presence is important, because of not only the involved complexity and cognitive load required in their use, but also for financial reasons. Investing money on features (e.g., software modules, programming time, maintenance and update, etc.) that are not valued by online consumers, hinders an efficient allocation of resources, especially when financial resources are scarce, a situation that corresponds too many small businesses operating on the internet. However, literature provides little help for managers to decide which functionalities should be implemented, according to a rational basis. Within this context, this research sought to fill in the gap between literature review and the need for helping companies to understand better how to build and keep online businesses. The authors work identified 16 essential functionalities grouped into four sets: order processing, advertising and prominence, product analysis, and payment.info:eu-repo/semantics/publishedVersio