With the increase of iOS applications on the market the demand and use of Backend as a Service (BaaS) providers also increase. In an early phase of the development it is beneficial for a potential application publisher to use a BaaS to quickly reach the market. Over time the provided services may be inadequate which make many BaaS users migrate to a custom developed backend. This paper intends to investigate which BaaS provider gives the least dismissed effort when making a transition to a custom developed backend with the purpose of providing basis for potential application publishers in the selection of a provider, given that a future transition to a custom backend will occur. From a population of ten providers, five were randomly selected – Firebase, Kinvey, CloudMine, Kumulos and Kii. In order to measure required effort for each provider, code that is tightly coupled to each provider’s SDK was implemented, according to provider guidelines and documentation. The implementations were measured with the COCOMO II model which gives a result in terms of required person months (PM). The measured PM of each implementation was compared. The hypothesis of the study could be rejected if the resulting PM of two implementations were disjointed. The result and analysis show difference in PM which lead to a rejection of the hypothesis. Whether the assumptions of the organization, product and project affected the results were analysed and the hypothesis was rejected regardless of these assumptions. If the organization of a potential application publisher resembles the one in the research Firebase is the recommended choice of BaaS provider.

The objective of this study has been to investigate and compare frontend javascript frameworks and cloud services in order to find which ones are most suitable to implement a web based product development application. The application will be based on the "House of Quality" methodology, which is commonly used in product development. It is basically a way to organize customer requirements, identify relevant quantifiable technical parameters and rank them in order to find out which ones are most important for the finished product. By using this very methodology on the application itself, the most important parameters were found to be data update delays and the need for additional services. The selected cloud services were benchmarked according to these parameters. For framework comparison, the methodology was based on existing research regarding what developers actually base their selection of frontend javascript frameworks on, which resulted in the metrics maturity, community size and documentation. SQL queries and benchmarking scripts were constructed in order to gather statistics from online services and run performance benchmarks. The results reveal substantial differences between frameworks as well as in performance among cloud services. A combination of the frontend framework Angular, the backend service Firebase and the authentication service Auth0 were found to be well suited for fulfilling the requirements of the product development application. Finally, potential problems, ethical considerations and areas where more research is required are discussed.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-15T13:05:35Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Disserta__o_Igor_Costa__Copy_(1).pdf: 11507063 bytes, checksum: f631fc6dd87314e89ea560a118301875 (MD5) / Made available in DSpace on 2016-03-15T13:05:35Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Disserta__o_Igor_Costa__Copy_(1).pdf: 11507063 bytes, checksum: f631fc6dd87314e89ea560a118301875 (MD5) Previous issue date: 2015-08-31 / As limitações da computação móvel abrem caminhos para utilizar recursos de computação em nuvem voltadas à dispositivos móveis, sendo este o principal objetivo da Mobile Cloud Computing (MCC). Questões como armazenamento e processamento podem afetar a disponibilidade de um serviço no dispositivo móvel, assim, para minimizar esses problemas é possível o particionamento da aplicação em frontend e backend. Os serviços de nuvem auxiliam esse processo com a utilização de ambientes Mobile Backend-as-a-Service (MBaaS), que permitem os desenvolvedores conectar o backend de suas aplicações para o armazenamento em nuvem. Uma plataforma de MBaaS oferece um serviço de sincronização completa para aplicações móveis. Uma vez que os dados armazenados no dispositivo móvel estão sincronizados com os centros de dados distribuídos, a disponibilidade do sistema no lado servidor é um atributo fundamental que requer investigação, pois sistemas computacionais tendem a falhar. As falhas podem ocorrer em hardwares, softwares e meios de conexão, acarretando assim, em prejuízos financeiros e comprometendo a credibilidade das empresas provedoras do serviço. Os administradores necessitam de mecanismos para estimar a disponibilidade de seus sistemas, podendo definir Service Level Agreement (SLA) com mais propriedade. Assim, modelos analíticos podem ser utilizados para avaliar a disponibilidade destes tipos de ambientes, bem como auxiliar a mitigar o downtime, aumentando a disponibilidade do serviço. Este trabalho propõe modelos analíticos para avaliar a disponibilidade desses ambientes. Para tanto, foi adotada uma metodologia: primeiramente definiu-se a arquitetura básica do serviço; a qual foi modelada a partir de um modelo hierárquico, composto de diagramas de blocos de confiabilidade (RBD) e cadeias de Markov de tempo contínuo (CTMC) e validado através de um testbed de injeção de falhas e reparos em um ambiente real. Baseado no modelo de serviço proposto, foi efetuada a análise de sensibilidade, que identificou o sistema como componente crítico. A partir disto, foram sugeridos modelos hierárquicos que representem o ambiente de nuvem, e com base neste ambiente, através da técnica de análise de sensibilidade, foram propostas quatro arquiteturas, sendo estas avaliados em termos de disponibilidade e downtime anual. Os resultados demonstram que a implementação de um processo de recuperação automática sobre o componente de software, Java Virtual Machine, reduz o downtime anual na arquitetura básica em cerca de 10%, bem como é possível observar que no ambiente de nuvem utilizando o mecanismo de redundância warm-standby nos nós e no frontend apresenta efetiva melhora na disponibilidade. Desta forma, a presente pesquisa pode orientar os administradores de sistemas MBaaS no planejamento de suas políticas de manutenção. / The mobile computer restrictions propose new ways to use cloud computing resources aimed at mobile devices, this is the Mobile Cloud Computing (MCC) primary goal. Issues such as storage and processing can impact the service availability on the mobile device. With the reducing purpose, these questions are its possible divide the application into two pieces, frontend, and backend. The cloud services assist this process with the Mobile Backend-as-a- Service (MBaaS) use. This tool allows the developers connect yours application backend to cloud storage. The MBaaS OpenMobster platform offers complete synchronization service to mobile applications. Since the data stored on mobile was synchronized distributed data center, the server’s system availability is an essential attribute and request attention, because computer systems will sometimes fail. The failures can happen on components variety as hardware, software and connections, causing financial losses and reliability compromising of the companies, which offer this services. The administrators need tools to project the system availability, with this they can define the SLA with more assurance. Analytic models can be used to availability evaluate in this environment and mitigate the downtime risk, this improves the service availability. This work primary goal is proposed analytic models to availability evaluated in these environments. It was adopted a methodology as follow: First, define the base service architecture. It was modeled by use a hierarchical model, using a reliability block diagram (RBD) and continuous-time Markov chain (CTMC). The validation considers a fault injection testbed and repairs on real environment. Considering the model proposed, it was done sensitivity analysis, these results present the system as a critical component. This analysis was proposed hierarchical models to represents cloud environment. On these sensibility analysis, a background was offered four scenarios. The scenarios were evaluated to determine the availability and annual downtime. The results show that the an automatic recovery implementation process on the software component, Java Virtual Machine, decrease the annual downtime on base architecture to 10%. The results present the availability improvement when adopted redundancy strategy as warm standby on a cloud environment. This way, the work can guide the MBaaS system administrators in planning their maintenance policies.