Automated Validation of State-Based Client-Centric Isolation with TLA ⁺

Clear consistency guarantees on data are paramount for the design and implementation of distributed systems. When implementing distributed applications, developers require approaches to verify the data consistency guarantees of an implementation choice. Crooks et al. define a state-based and client-centric model of database isolation. This paper formalizes this state-based model in, reproduces their examples and shows how to model check runtime traces and algorithms with this formalization. The formalized model in enables semi-automatic model checking for different implementation alternatives for transactional operations and allows checking of conformance to isolation levels. We reproduce examples of the original paper and confirm the isolation guarantees of the combination of the well-known 2-phase locking and 2-phase commit algorithms. Using model checking this formalization can also help finding bugs in incorrect specifications. This improves feasibility of automated checking of isolation guarantees in synthesized synchronization implementations and it provides an environment for experimenting with new designs.</p

Dynamics of Long-Life Assets: From Technology Adaptation to Upgrading the Business Model

Knowledge management; Business information system

Dynamics of Long-Life Assets: From Technology Adaptation to Upgrading the Business Model

The editors present essential methods and tools to support a holistic approach to the challenge of system upgrades and innovation in the context of high-value products and services. The approach presented here is based on three main pillars: an adaptation mechanism based on a broad understanding of system dependencies; efficient use of system knowledge through involvement of actors throughout the process; and technological solutions to enable efficient actor communication and information handling.The book provides readers with a better understanding of the factors that influence decisions, and put forward solutions to facilitate the rapid adaptation to changes in the business environment and customer needs through intelligent upgrade interventions. Further, it examines a number of sample cases from various contexts including car manufacturing, utilities, shipping and the furniture industry. The book offers a valuable resource for both academics and practitioners interested in the upgrading of capital-intensive products and services

A Computational Framework for Resilience-Informed Design

It is desirable for complex engineered systems to perform missions efficiently and economically, even when these missions' complex, variable, long-term operational profiles make it likely for hazards to arise. It is thus important to design these systems to be resilient so that they will actively prevent and recover from hazards when they occur. To most effectively design a system to be resilient, the resilience of each design alternative should be quantified and valued so that it can be incorporated in the decision-making process. However, considering resilience in early design is challenging because resilience is a dynamic and stochastic property characterizing how the system performs over time in a set of unlikely-but-salient hazardous scenarios. Quantifying these properties thus requires a model to simulate the system's dynamic behavior and performance over the set of hazardous scenarios. Thus, to be able to incorporate resilience in the design process, there is a need to develop a framework which implements and integrates these models with design exploration and decision-making. This dissertation fulfills this need by defining resilience to enable fault simulations to be incorporated in decision-making, devising and implementing a modelling framework for early assessment of system resilience attributes, and exploring optimization architectures to efficiently structure the design exploration of resilience variables. Additionally, this dissertation provides a validity testing framework to determine when the resilient design process has been effective given the uncertainties present in the design problem. When each of these parts are used together, they comprise an overall framework that can be used to consider and incorporate system resilience in the early design process