Computação em nuvem é uma solução adequada para profissionais, empresas, centros de pesquisa e instituições que necessitam de acesso a recursos computacionais sob demanda. Atualmente, nuvens computacionais confiam no gerenciamento de sua estrutura para fornecer recursos computacionais com qualidade de serviço adequada as expectativas de seus clientes, tal qualidade de serviço é estabelecida através de acordos de nível de serviço. Nesse contexto, o monitoramento é uma função crítica de gerenciamento para se prover tal qualidade de serviço. Requisitos de monitoramento em nuvens computacionais são propriedades que um sistema de monitoramento de nuvem precisa reunir para executar suas funções de modo adequado e atualmente existem diversos requisitos definidos pela literatura, tais como: oportunidade, elasticidade e escalabilidade. Entretanto, tais requisitos geralmente possuem influência mútua entre eles, que pode ser positiva ou negativa, e isso impossibilita o desenvolvimento de soluções de monitoramento completas. Dado o cenario descrito acima, essa tese tem como objetivo investigar a influência mútua entre escalabilidade e oportunidade. Especificamente, essa tese propõe um modelo matemático para estimar a influência mútua entre tais requisitos de monitoramento. A metodologia utilizada por essa tese para construir tal modelo matemático baseia-se em parâmetros de monitoramento tais como: topologia de monitoramento, quantidade de dados de monitoramento e frequencia de amostragem. Além destes, a largura de banda de rede e o tempo de resposta também são importantes métricas do modelo matemático. A avaliação dos resultados obtidos foi realizada através da comparação entre os resultados do modelo matemático e de uma simulação. As maiores contribuições dessa tese são divididas em dois eixos, estes são denominados: Básico e Chave. As contribuições do eixo básico são: (i) a discussão a respeito da estrutura de monitoramento de nuvem e introdução do conceito de foco de monitoramento (ii) o exame do conceito de requisito de monitoramento e a proposição do conceito de abilidade de monitoramento (iii) a análise dos desafios e tendências a respeito de monitoramento de nuvens computacionais. As contribuições do eixo chave são: (i) a discussão a respeito de oportunidade e escalabilidade incluindo métodos para lidar com a mútua influência entre tais requisitos e a relação desses requisitos com parâmetros de monitoramento (ii) a identificação dos parâmetros de monitoramento que são essenciais na relação entre oportunidade e escalabilidade (iii) a proposição de um modelo matemático baseado em parâmetros de monitoramento que visa estimar a relação mútua entre oportunidade e escalabilidade. / Cloud computing is a suitable solution for professionals, companies, research centres, and institutions that need to have access to computational resources on demand. Nowadays, clouds have to rely on proper management of its structure to provide such computational resources with adequate quality of service, which is established by Service Level Agreements (SLAs), to customers. In this context, cloud monitoring is a critical management function to achieve it. Cloud monitoring requirements are properties that a cloud monitoring system need to meet to perform its functions properly, and currently there are several of them such as timeliness, elasticity and scalability. However, such requirements usually have mutual influence, which is either positive or negative, among themselves, and it has prevented the development of complete cloud monitoring solutions. From the above, this thesis investigates the mutual influence between timeliness and scalability. This thesis proposes a mathematical model to estimate such mutual influence to enhance cloud monitoring systems. The methodology used in this thesis is based on monitoring parameters such as monitoring topologies, the amount of monitoring data, and frequency sampling. Besides, it considers as important metrics network bandwidth and response time. Finally, the evaluation is based on a comparison of the mathematical model results and outcomes obtained via simulation. The main contributions of this thesis are divided into two axes, namely, basic and key. Basic contributions of this thesis are: (i) it discusses the cloud monitoring structure and introduced the concept of cloud monitoring focus (ii) it examines the concept of cloud monitoring requirement and proposed to divide them into two groups defined as cloud monitoring requirements and cloud monitoring abilities (iii) it analysed challenges and trends in cloud monitoring pointing research gaps that include the mutual influence between cloud monitoring requirements which is core to the key contributions. The key contributions of this thesis are: (i) it presents a discussion of timeliness and scalability that include: the methods currently used to cope with the mutual influence between them, and the relation between such requirements and monitoring parameters (ii) it identifies the monitoring parameters that are essential in the relation between timeliness and scalability (iii) it proposes a mathematical model based on monitoring parameters to estimate the mutual influence between timeliness and scalability.

This work aims to investigate the state of the art in test case generation for real-time systems, to analyze existing methods, and to propose future research directions in this area. We believe that a combination of design for testability, automation, and sensible test case selection is the key for verifying modern real-time systems. Existing methods for system-level test case generation for real-time systems are presented, classified, and evaluated against a real-time system model. Significant for real-time systems is that timeliness is crucial for their correctness. Our system model of the testing target adopts the event-triggered design paradigm for maximum flexibility. This paradigm results in target systems that are harder to test than its time-triggered counterpart, but the model improves testability by adopting previously proposed constraints on application behavior. This work investigates how time constraints can be tested using current methods and reveals problems relating to test-case generation for verifying such constraints. Further, approaches for automating the test-case generation process are investigated, paying special attention to methods aimed for real-time systems. We also note a need for special test-coverage criteria for concurrent and real-time systems to select test cases that increase confidence in such systems. We analyze some existing criteria from the perspective of our target model. The results of this dissertation are a classification of methods for generating test cases for real-time systems, an identification of contradictory terminology, and an increased body of knowledge about problems and open issues in this area. We conclude that the test-case generation process often neglects the internal behavior of the tested system and the properties of its execution environment as well as the effects of these on timeliness. Further, we note that most of the surveyed articles on testing methods incorporate automatic test-case generation in some form, but few consider the issues of automated execution of test cases. Four high-level future research directions are proposed that aim to remedy one or more of the identified problems.

Data aggregation is extensively used in data management systems nowadays. Based on a data aggregation taxonomy named DAGGTAX, we propose an analytic process to evaluate the run-time platform and time-related parameters of Data Aggregation Processes (DAP) in a real-time system design, which can help designers to eliminate infeasible design decisions at early stage. The process for data aggregation design and analysis mainly includes the following outlined steps. Firstly, the user needs to specify the variation of the platform and DAP by figuring out the features of the system and time-related parameters respectively. Then, the user can choose one combination of the variations between the features of the platform and DAP, which forms the initial design of the system. Finally, apply the analytic method for feasibility analysis by schedulability analysis techniques. If there are no infeasibilities found in the process, then the design can be finished. Otherwise, the design must be altered from the run-time platform and DAP design stage, and the schedulability analysis will be applied again for the revised design until all the infeasibilities are fixed. In order to help designers to understand and describe the system and do feasibility analysis, we propose a new UML (Unified Modeling Language) profile that extends UML with concepts related to real-time data aggregation design. These extensions aim to accomplish the conceptual modeling of a real-time data aggregation. In addition, the transferring method based on UML profile to transfer the data aggregation design into a task model is proposed as well. In the end of the thesis, a case study, which applies the analytic process to analyze the architecture design of an environmental monitoring sensor network, is presented as a demonstration of our research.

Syfte: “Studiens syfte är att undersöka vad som förklarar svenska onoterade företags benägenhet att lämna in sin årsredovisning i ett tidigt eller sent skede”.   Metod: I denna kvantitativa studie har sekundärdata samlats in från databasen Retriever. För att uppnå studiens syfte används multivariata regressionsanalyser med lead time och i tid/sen som beroende variabler och lönsamhet, ålder, storlek, revision, skuldsättning, bokslutsmånad samt bransch som oberoende variabler.   Resultat och Slutsats: Resultaten visar på ett negativt signifikant samband mellan lead time och lönsamhet. Sambandet mellan lead time och företagets bokslutsmånad var positivt och signifikant. Företagens val att ha revisor visade sig även det ha ett positivt signifikant samband med lead time, vilket innebär att företag med revisor kommer att lämna in sin årsredovisning senare än företag utan revisor. Det finns däremot inget som tyder på att ha en revisor eller inte påverkar huruvida företag lämnar i tid eller inte.   Bidrag: Studien har bidragit till forskningsområdet kring aktualitet dels genom att utföra studien i Sverige och dels genom att studera onoterade företag. Detta har medfört att en variabel som inte tidigare har studerats, företagets val att ha revisor eller inte, har kunnat inkluderas. Studien bidrar även till de senaste årens debatt kring tidsgränsen för hur sent årsredovisningar ska få lämnas in.   Förslag till vidare forskning: Ett förslag till vidare forskning är att studera om årsredovisningars aktualitet förändrades i och med avskaffandet av revisionsplikten. Det hade även varit intressant att utföra en liknande studie med longitudinell design där flera år undersöks för att kunna fastställa orsaksriktningen mellan variablerna. / Aim: “The aim of this study is to examine what explains Swedish unlisted companies’ tendency to file their annual reports in an early or late period”.   Method: In this quantitative study secondary data is obtained from the database Retriever. To achieve the aim of this study multivariate regression analyses are used with lead time and in time/late as the dependent variables and profitability, age, size, audit, leverage, fiscal year-end and sector as independent variables.   Results and Conclusions: The results show a negative relationship between lead time and profitability. The relationship between lead time and company fiscal year-end was positive and significant. If a company have chosen to have an auditor is shown to have a positive significant relationship with lead time, this mean that companies with an auditor will file their annual reports later than companies without an auditor. There is on the other hand no indications that having an auditor or not will affect whether the company file on time or not.   Contributions: This study has contributed to the field of research of timeliness partly by performing the study in Sweden and partly by studying unlisted companies. This resulted in the inclusion of a variable that takes into account if the company has an auditor or not, which has not been studied before. The study also contributes to previous years debate about the time allowed for companies to file their annual reports.   Suggestions for future research: A suggestion for future research is to study if the timeliness of annual reports changed as a result of the abolition of the audit obligation. It would also be interesting to conduct a similar study with a longitudinal design where more than one year is reviewed so that the causal direction of the variables can be determined.

There is scarce research that implement a formal framework when evaluating usability evaluation methods such as heuristicevaluation. This paper aimed to explore and compare the results of a heuristic evaluation performed by end-users and a heuristicevaluation performed by experts. Both heuristic evaluations took place in the context of forestry industry where a mobileapplication developed to give harvest operators performance feedback was evaluated. A thorough literature review for researchregarding evaluation of UEM was a crucial first step. The outcome of this produced an evaluation framework that included threecriteria, Relevance, Frequency and Timeliness. These criteria were used to analyse the results from the heuristics evaluationsperformed by the two groups, using mixed methods. The quantitative analysis concluded that the evaluation performed by theend-users had a higher frequency and relevance value, and that the evaluation performed by the expert group had higher valuefor their solution rate in the timeliness criteria. Furthermore, the qualitative analysis held within the criteria timeliness concludedthat the two groups identified different types of usability problems, confirming previous research performed on different types ofheuristic evaluators.

No description available.

In the late 1980s and early 1990s few transportation agencies around the world considered performance-based specifications as an alternative to improve the efficiency of the services provided to the public. These initiatives are better known as Performance-Based Road Maintenance (PBRM). PBRM calls for performance-based work, in which a desired outcome is specified rather than a material or method. This type of specification promises to be an excellent tool to improve government efficiency in maintaining transportation networks; however, without proper monitoring, it could likely yield adverse outcomes. Since PBRM is relatively new, the availability of reliable and comprehensive sets of guidelines to evaluate the effectiveness and efficiency of this type of specifications in the roadway maintenance arena is limited. Transportation agencies currently rely on criteria and procedures they have had developed from their traditional methods used to evaluate performance. Unfortunately, some of these procedures cannot appropriately assess the benefits, if any, accrued by the government as a result of implementing performance-based specifications for the maintenance of the roadway system. This research presents the development of a framework for monitoring PBRM more comprehensively and accurately. The framework considers the assessment of five main areas -- Level of Service Effectiveness, Cost-Efficiency, Timeliness of Response, Safety Procedures, and Quality of Services -- in order to guarantee the comprehensiveness and reliability of the evaluation process. The major contribution of this framework is to provide transportation agencies with guidelines for evaluating the effectiveness and efficiency of PBRM as an alternative delivery method to maintain and preserve the roadway system. / Ph. D.

Esta dissertação tem o propósito principal de fornecer evidências empíricas acerca dos fatores que influenciam as decisões dos gestores quanto ao prazo de divulgação das demonstrações contábeis anuais das companhias não financeiras listadas na BM&FBOVESPA. O prazo de divulgação, chamado defasagem, foi medido como o intervalo em dias entre o encerramento do exercício social e a data da primeira apresentação das Demonstrações Financeiras Padronizadas (DFPs). O foco da pesquisa foi a influência, sobre a defasagem, dos seguintes fatores não observáveis: monitoramento, complexidade contábil, governança corporativa, relatório de auditoria e performance. Com base na literatura revisada, foram formuladas proxies destinadas a captar os efeitos desses fatores. Para a consecução dos objetivos, foram estimados modelos econométricos por meio dos métodos: (i) Mínimos Quadrados Ordinários (MQO) com dados em corte transversal; (ii) MQO com dados agrupados (OLS pooled); e (iii) painel de dados. Os testes foram aplicados sobre um painel balanceado de dados, ou seja, 644 observações de 322 companhias, referentes aos exercícios 2010 e 2011. Os resultados das estimações revelaram que tendem a divulgar mais rapidamente suas demonstrações companhias: (i) com maior número de acionistas; (ii) com maior nível de endividamento; (iii) que aderiram a um entre os níveis diferenciados de governança corporativa da BM&FBOVESPA; (iv) que possuem maiores proporções de diretores independentes na composição da diretoria (board); e (v) que foram auditadas por uma entre as firmas de auditoria do grupo Big-4. Por outro lado, constatou-se que tendem a atrasar suas divulgações companhias que: (i) estão sujeitas à consolidação de balanços; (ii) tiveram suas demonstrações contábeis ressalvadas pelos auditores independentes; (iii) e que registraram resultados negativos (prejuízos). Adicionalmente, foram formuladas proxies para captar os efeitos das surpresas contidas nos resultados, uma delas tendo como base o benchmark para as expectativas do mercado, qual seja, a previsão dos analistas, no entanto, não foram constatados impactos das surpresas sobre o prazo de divulgação. Também não foram verificadas influências, sobre o timing, oriundas da proporção de investidores institucionais, da formação de blocos de controle, da regulação estatal, do nível de rentabilidade, do porte e tampouco da negociação de valores mobiliários em mercados estrangeiros. Os achados desta pesquisa podem contribuir não apenas para a literatura dedicada a essa linha de pesquisa, como também para investidores, analistas de mercado e reguladores. As nuances observadas para os exercícios analisados, que marcaram a adoção integral do padrão contábil alinhado às normas IFRS e a recuperação da economia brasileira em relação aos impactos da crise financeira mundial, permitiram relevantes constatações. Além disso, a relevância deste estudo é ampliada pelo ineditismo presente na aplicação de proxies ainda não utilizadas em ambiente nacional para explicar os prazos de divulgação.

Esta dissertação tem o propósito principal de fornecer evidências empíricas acerca dos fatores que influenciam as decisões dos gestores quanto ao prazo de divulgação das demonstrações contábeis anuais das companhias não financeiras listadas na BM&FBOVESPA. O prazo de divulgação, chamado defasagem, foi medido como o intervalo em dias entre o encerramento do exercício social e a data da primeira apresentação das Demonstrações Financeiras Padronizadas (DFPs). O foco da pesquisa foi a influência, sobre a defasagem, dos seguintes fatores não observáveis: monitoramento, complexidade contábil, governança corporativa, relatório de auditoria e performance. Com base na literatura revisada, foram formuladas proxies destinadas a captar os efeitos desses fatores. Para a consecução dos objetivos, foram estimados modelos econométricos por meio dos métodos: (i) Mínimos Quadrados Ordinários (MQO) com dados em corte transversal; (ii) MQO com dados agrupados (OLS pooled); e (iii) painel de dados. Os testes foram aplicados sobre um painel balanceado de dados, ou seja, 644 observações de 322 companhias, referentes aos exercícios 2010 e 2011. Os resultados das estimações revelaram que tendem a divulgar mais rapidamente suas demonstrações companhias: (i) com maior número de acionistas; (ii) com maior nível de endividamento; (iii) que aderiram a um entre os níveis diferenciados de governança corporativa da BM&FBOVESPA; (iv) que possuem maiores proporções de diretores independentes na composição da diretoria (board); e (v) que foram auditadas por uma entre as firmas de auditoria do grupo Big-4. Por outro lado, constatou-se que tendem a atrasar suas divulgações companhias que: (i) estão sujeitas à consolidação de balanços; (ii) tiveram suas demonstrações contábeis ressalvadas pelos auditores independentes; (iii) e que registraram resultados negativos (prejuízos). Adicionalmente, foram formuladas proxies para captar os efeitos das surpresas contidas nos resultados, uma delas tendo como base o benchmark para as expectativas do mercado, qual seja, a previsão dos analistas, no entanto, não foram constatados impactos das surpresas sobre o prazo de divulgação. Também não foram verificadas influências, sobre o timing, oriundas da proporção de investidores institucionais, da formação de blocos de controle, da regulação estatal, do nível de rentabilidade, do porte e tampouco da negociação de valores mobiliários em mercados estrangeiros. Os achados desta pesquisa podem contribuir não apenas para a literatura dedicada a essa linha de pesquisa, como também para investidores, analistas de mercado e reguladores. As nuances observadas para os exercícios analisados, que marcaram a adoção integral do padrão contábil alinhado às normas IFRS e a recuperação da economia brasileira em relação aos impactos da crise financeira mundial, permitiram relevantes constatações. Além disso, a relevância deste estudo é ampliada pelo ineditismo presente na aplicação de proxies ainda não utilizadas em ambiente nacional para explicar os prazos de divulgação.

This thesis contributes to the literature in the finance and accounting field throughout its three empirical chapters. The first empirical chapter contributes to the literature on accounting conservatism in several ways; first, it investigates the accounting conservatism of US insurance companies using four measures, namely, non-operating accruals, skewness of earnings and cash flows, book to market ratio and asymmetric timeliness measures. Second, this paper compares these four measures in order to determine the association and differences between them. Finally, the level of accounting conservatism of the insurance companies is compared to that of a sample of commercial banks to check whether they have similar levels of accounting conservatism. The results of the first chapter suggest that the changes in accounting performance, as measured by return over assets, can be partly explained by accounting conservatism, since it is measured by the accumulation of non-operating accruals, skewness of operating cash flow and accruals, book to market ratio, adjusted book to market ratio and Basu's asymmetric measure. All of these four measures give robust evidence that insurance companies' accounts tended to be conservative for the whole sample period, and that the level of conservatism has risen over the years. More interestingly, a t test for the differences in means suggests that accruals conservatism show on average a higher level of accounting conservatism than book value conservatism does. Finally, our results, based on a constant sample consist of 92 banks and 46 insurance companies whose data are available for all the sample years; they suggest that both insurance companies and banks have similar levels of accounting conservatism due to their similar reporting characteristics. The second empirical chapter contributes to the existing literature on equity valuation in two ways. First, it confirms the importance of imposing linear information dynamics when predicting the equity values of insurance companies, because the restricted models result in fewer error metrics. Second, it highlights the role of the accruals components in the equity valuation of US insurance companies by demonstrating that the incorporation of accrual components in the residuals income valuation model suggested by Ohlson (1995) has smaller error metrics than those of aggregate net income. Our results are based on a sample of US insurance companies, which consists of 718 firm-year observations over the period from 2001 to 2012. For instance, our results suggest that total accruals, changes in insurance reserve, changes in account receivables, and deferred acquisition costs have an incremental ability to predict equity market value over abnormal earnings and book values. Furthermore, the predictive ability of changes in insurance reserves is higher than the predictive ability of changes in account receivables and the change in deferred acquisition costs without imposing the LIM structures. However, when the LIM structure is imposed the predictive ability of changes in deferred acquisition costs is higher than the predictive ability of both changes in accounts receivable and changes in insurance reserves. Our final empirical chapter contributes to the literature on accounting anomalies by investigating the value to price anomaly (V/P), where the fundamental value (V) is estimated using the residual income valuation model. Motivated by the findings of Hwang and Lee (2013), Fama and French (2015), and Fama and French (2016), Chapter Four asks whether V/P strategies reflect the risks factor or whether this is better explained by market inefficiency, and whether Fama and French's five-factor model can explain the excess return of V/P. To answer the previous questions we use data from the merger of COMPUSTAT, CRSP, I/B/E/S for all the non-financial firms listed in AMEX, NYSE, and NASDAQ during the period from 1987 to 2015. Our findings suggest that the V/P ratio is positively correlated to future stock returns after controlling for several firm characteristics, which are known to be proxies of common risks. Our results indicate that the omission of risk factors is not likely to be an explanation of the V/P effect. To answer the second question, we compare the performances of different asset pricing models by calculating the GRS F-statistics. Our findings clearly indicate that the five-factor model of Fama and French performs better than either the CAPM or the traditional Fama and French three factor model. These results confirm that the excess returns of V/P strategy vary due to the differences in size, the B/M ratio, operating profit and betas across quintile portfolios. However, these factors cannot explain all the variation in excess returns; moreover, the stocks in the high V/P may be riskier than the stocks in the low V/P portfolios in certain other dimensions.