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Deploying networks onboard mass transit vehicles, e.g., trains and buses, and connecting these moving networks to the Internet using cellular or satellite services is seen as a promising technology to meet the broadband demand in the transport sector. This thesis examines the problem of service disruptions in such moving networks and proposes original solutions to manage these disruptions. Service disruption is caused by two main reasons. First, unavailability of wireless resources in the back-haul (e.g., cellular) network may prevent successful handoff of all passenger calls when the moving vehicle leaves the coverage of one radio tower and enters another. Second, the moving network may face frequent network disconnections when the vehicle travels through environments with severe radio coverage, e.g., tunnels. To address service disruption due to back-haul resource unavailability, an advance resource reservation frame work is proposed whereby the deterministic mobility of public transport is exploited to reserve bandwidth at target radio base-stations along the route of the vehicle. The viability of the proposed advance reservation framework is validated by (i) a predictability analysis of resource demand of moving networks using real passenger data, which show that it is possible to predict the demand at an upcoming location based on past data and the passenger count at the current location, and (ii) design of cellular extensions which show that advance reservation not only can be accommodated in existing cellular architectures with minimal modifications, it can also guarantee fast and scalable access to massive reservation data. To quantify the effect of temporary network disconnections on the probability of service disruption, new mathematical models have been developed and validated by computer simulation. Finally, a novel proactive admission control (PAC) approach is proposed to reduce service disruption by rejecting new call requests when the moving network is predicted to experience an imminent network disconnection. Using mathematical modelling, it has been demonstrated that PAC reduces service disruption probability exponentially as a function of the proactive decision time with only a linear increase in the new call blocking probability. Practicality of the PAC approach has been confirmed using empirical data from actual vehicular trips.

Cloud computing provides access to on-demand computing resources and storage space, whereby applications and data are hosted with data centers managed by third parties, on a pay-per-use price model. This allows organizations to focus on core business goals instead of managing in-house IT infrastructure.                     However, as more business critical applications and data are moved to the cloud, service availability is becoming a growing concern. A number of recent cloud service disruptions have questioned the reliability of cloud environments to host business critical applications and data. The impact of these disruptions varies, but, in most cases, there are financial losses and damaged reputation among consumers.         This thesis aims to investigate the threats to service availability in cloud computing and to provide some best practices to mitigate some of these threats. As a result, we identified eight categories of threats. They include, in no particular order: power outage, hardware failure, cyber-attack, configuration error, software bug, human error, administrative or legal dispute and network dependency. A number of systematic mitigation techniques to ensure constant availability of service by cloud providers were identified. In addition, practices that can be applied by cloud customers and users of cloud services, to improve service availability were presented.

在後數位化時代，有無數的數位服務生態圈在爭奪著有限的市場。而要贏得這場競爭最好的方式就是遵照服務設計的理論來滿足顧客的渴望。本研究期望運用科技化的輔助方式來幫助服務設計者建立一個以顧客主導邏輯為基礎的區塊鏈服務生態系統。在這個方法裡面，我們必須要解譯服務設計者的服務價值主張，並且找出與之相關的價值活動來作為之後服務設計的樣本。最後透過服務渴望度、創新度以及利害關係人認可程度三個面向來衡量整個價值結構設計是否可行並有發展潛力。 / In the post-digital era, there are countless digital ecosystems to fight for the limited market share. Using service design theory to fulfill customers’ desire is the best way to win the competence. This paper proposes a technology facilitating approach to help service designers configure their blockchain-based service ecosystem with customer-dominate logic. We rephrase the service value proposition inputted by service designers and filtering related value activities as the model of designed ecosystem. To make the decentralized ecosystem become a destination, we have to examine the value configuration from three different perspectives which are desirability, disruption, and consensus. These three dimensions provide service designers with a method that can help assess if a configuration is making sense or not. After all, this paper is aimed to support service designers to create a digital destination ecosystem by recommending activities and evaluating score of ecosystem configuration.