Concurrency in Android development – Kotlin Coroutines and RxJava

A faulty concurrency system may have an impact in the user experience of the software product and consequently to the company that owns that product. The main goal of this research is to understand the impact of concurrency in Android development and further help developers/companies to discretise the best approaches for concurrency. The research initially centres on the importance of concurrency in Android applications as well as the main approaches for concurrency/threading in Android development. It further illustrates why some asynchronous programming approaches do not fit modern Android development. This allowed the research to concentrate on the most relevant approaches to concurrency and consequently produce more pertinent results for the current state of Android development. After acknowledging Kotlin Coroutines and RxJava as the most relevant approaches to concurrency for Android (at the time of writing this document), this research moved on with the development of a case study application. This application was implemented using both Kotlin Coroutines and RxJava while reusing as much code as possible. There is a single module dedicated to the main user interface of the application and two modules (one for Kotlin Coroutines and one for RxJava) dedicated to concurrently run the necessary steps for each feature and further propagating the necessary data to the user interface. This allowed a clear separation of the specific code needed to perform the same features with Kotlin Coroutines and RxJava, facilitating its later comparison. The design of this application and its features required prior assessment of common use cases for concurrency in Android to form a fitting case study. With the intent of assessing the impact of using Kotlin Coroutines and RxJava in Android applications, we discretised the main software quality attributes to consider for Android development. By taking this step, we were able to focus mainly on the Performance and Maintainability of an Android application and understand how the usage of both Kotlin Coroutines and RxJava affects these attributes. The impact of each library in the performance and maintainability of an Android application was measured using software metrics that were provided by a combination of static analysis, benchmarks, and profiling tests. The process of designing the set of tests, setting up the required tools and the overall development of the test environment for this research is also explored in this document. The results for Kotlin Coroutines and RxJava were then illustrated, compared, and interpreted to fulfil our objective of understanding if, at the time of writing this document, there is a more sensible approach to concurrency for Android development according to our set of tests. The results for our set of tests and case study application revealed that RxJava and Kotlin Coroutines do not differently compromise the performance and maintainability of an Android application, for what developers and companies should not be limited when choosing between these libraries

Dubrovin Frobenius manifolds, Hurwitz spaces, and Extended Jacobi groups.

I define a certain extension of the Jacobi group An, and a Dubrovin-Frobenius structure is constructed on its orbit space

Anderson localization on the Falicov-Kimball model with Coulomb disorder

The role of Coulomb disorder is analysed in the Anderson-Falicov-Kimball model. Phase diagrams of correlated and disordered electron systems are calculated within dynamical mean-field theory applied to the Bethe lattice, in which metal-insulator transitions led by structural and Coulomb disorders and correlation can be identified. Metallic, Mott insulator, and Anderson insulator phases, as well as the crossover between them are studied in this perspective. We show that Coulomb disorder has a relevant role in the phase-transition behavior as the system is led towards the insulator regime

Financial reporting about provisions: evidence from Portuguese listed companies

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsThis project provides evidence about the practices of financial reporting regarding provisions namely presentation, recognition, measurement and disclosure in the consolidated annual reports in 2010 and 2009 of Portuguese non-financial companies listed in the Euronext Lisbon. Moreover it updates the findings of previous literature, analyzes the compliance with IAS 37 and identifies its main issues. The findings suggest that there exists room for improvement of provisions reporting in Portugal, as requirements are in some cases not followed in full and there is unclear information, so the research recommends to regulators, preparers and users in order to address those issues

A Study of Canadian Bankruptcies, 2014-2022

This paper studies Canadian monthly bankruptcy data from January 2014 to February 2022 with an aim towards identifying the existence of underlying heterogeneity in the decision-making of firms across different industry sectors during periods of economic adversity. The data used include provincial two-digit NAICS bankruptcy level data, provincial pandemic-related data concerning the evolution of cases and stringency of adopted policies, and external factors pertaining to the domestic and foreign economies such as industry GDP, the overnight rate target, exchange rates, imports and exports, prices, and bond liquidity premium. The method is two-fold. First, we identify changes in bankruptcy trends caused by the pandemic both provincially and by industry sector, and then contrast the findings with the results from a zero-inflated Poisson GLM model that assesses the probability of bankruptcies occurring at different points in time given the set of inputs described above. Second, the model is used to predict bankruptcy numbers for three different intervals during the reference period: 2019, 2020-2022, and 2021-2022. It is noted that despite the model’s ability to accurately predict bankruptcy values for 2019, its accuracy decreases for the pandemic period, even when pandemic-related variables are controlled for. The conclusion is that the drop in Canadian bankruptcies during the pandemic seen in the data must be accounted for some other factor that upheld firms’ continued operations. The presence of underlying heterogeneity is inferred from the fact that if heterogeneity was not present, then controlling for industry sector would suffice to capture the effect of such a program, thus increasing the accuracy of predictions for the pandemic period

Equity research: Jerónimo Martins SGPS, SA

The main objective of this dissertation is to carry out a global valuation of Jerónimo Martins and determine its value per share based on cash flows forecasts. In that sense, an analysis of the company was made, as well as a market study regarding the evolution of the retail industry. Jerónimo Martins SGPS is a Portuguese company, leader in the food retail market in Poland and one of the major players in the Portuguese market, beyond that it is also presence in the Colombian market. Jerónimo Martins also operates in the specialized retail, namely in cosmetics and confectionery markets and in the agribusiness industry. On 31/12/2020 Jerónimo Martins SGPS was listed on the Euronext Lisbon stock exchange and closed the year with a value of €13.82 per share. To determine the company value three valuation methods were used, the DCF, the EVA and the multiples methodology. According with the DCF model, the target price is €13.92, which represents an appreciation of 0.76% and thus the value offered by the market does not recognize the potential growth of the company. A sensitivity analysis was also performed to analyse the sensitivity of the share price to the discount rate and to the perpetual growth rate, two of the most crucial variables. In conclusion, it was done a comparative analysis of the results obtained through the several methods, which lead to a Buy recommendation, in line with the analysis carried out by CAIXA BANK.Esta dissertação tem como principal objetivo realizar uma avaliação global à Jerónimo Martins e determinar o valor das suas ações com base nas perspetivas futuras. Para isso, foi feita uma análise da empresa e também um estudo ao mercado que engloba a evolução do setor do retalho. A Jerónimo Martins SGPS é uma empresa portuguesa, líder no mercado alimentar na Polónia e um dos maiores players no mercado português e conta ainda com presença no mercado Colombiano. A Jerónimo Martins tem também presença no retalho especializado, nomeadamente em cosmética e confeitaria e também no mercado agro-alimentar. A 31/12/2020 a Jerónimo Martins SGPS estava cotada na bolsa de valores Euronext Lisboa e fechou o ano com as ações a valerem 13.82 euros Para determinar o valor da empresa vão ser utilizados três métodos de avaliação, o DCF, o EVA e por último, foi utilizado o método dos múltiplos. Segundo o modelo DCF, o preço alvo é de €13.92, o que representa uma apreciação de 0.76% e deste modo o valor oferecido pelo mercado não reconhece o potencial crescimento da empresa. Foi também realizado uma análise de sensibilidade tendo por base variações em duas das variáveis mais críticas, para que seja possível avaliar a sensibilidade do preço da ação relativamente à taxa de desconto e à taxa de crescimento perpétuo. Em suma, é também realizada uma comparação dos resultados obtidos através dos diversos métodos, o que origina uma recomendação de compra, em linha com a análise realizada pelo CAIXA BANK