The life and times of a learning technology system: the impact of change and evolution

With the inception of the web now being more than 20 years ago, many web-based learning technology systems (LTS) have had a long life and have undergone many changes, both affecting content and infrastructure technologies. A change factor model can capture the various factors causing LTS to change. Methods for change-aware design of LTS have been suggested. The purpose of this investigation is, firstly, to add empirical results to aspects of these models and methods in order to show the relevance of such a change factor model by specifically looking at an LTS that has been developed, maintained and extended over a period of 20 years. Secondly, these results shall be used to develop a conceptual model capturing and assessing the impact of change. A key observation is an unexpectedly high impact of environmental constraints on the LTS, but also new opportunities emerging over time have had dramatic changes as their consequence

Evolution of security engineering artifacts: a state of the art survey

Security is an important quality aspect of modern open software systems. However, it is challenging to keep such systems secure because of evolution. Security evolution can only be managed adequately if it is considered for all artifacts throughout the software development lifecycle. This article provides state of the art on the evolution of security engineering artifacts. The article covers the state of the art on evolution of security requirements, security architectures, secure code, security tests, security models, and security risks as well as security monitoring. For each of these artifacts the authors give an overview of evolution and security aspects and discuss the state of the art on its security evolution in detail. Based on this comprehensive survey, they summarize key issues and discuss directions of future research

Overview of International Waste Management Activities in Fusion

The minimization of active waste from the operation and decommissioning of a fusion power plant is a common goal of fusion development programs in Europe and in the US. Approaches differ, according to national regulations, and include reuse and recycling, clearance for non-active disposal or free-release recycling, and shallow land burial. Adopting the minimization of active waste volume as a design requirement leads to a Low Activation Design if properly optimized for materials choices. Power plant studies, both ARIES in the US and the PPCS in Europe, are adopting strategies to meet such requirements. International collaboration, particularly in the frame of an IEA co-operative program, provides benefits in the development of waste management strategie