Ensuring reliability in Component-Based Software Systems (CBSSs) is important for their effective applications in large scale and safety critical systems. However, only few techniques consider failure propagation in system architectures for system reliability assessment. Those techniques focus only on content failure propagation through component interfaces. Therefore, the evaluation of CBSS architectures based on the current techniques fails to consider the impacts of all failure types on system reliability. In this paper, we present a failure propagation analysis technique for CBSSs. We analyze failure propagation based on architectural service routes (ASRs). An ASR is a sequence of components that are connected through interfaces. We discuss the attributes of ASRs with respect to system components and present their impacts on failure propagation and consequently on the reliability of CBSSs. Further analysis determines upper and lower bounds of failure propagation among components and shows some relationships between system reliability and architectural attributes. Our technique is not limited to any failure type, and it considers failure scattering and masking. Therefore, unlike other works, the proposed technique demonstrates more accurate representation of the practical aspect of failure propagation in CBSSs. The technique can also be used to achieve reliable designs in the early design stages of CBSSs and to localize component faults in the operational stage. We compare different example architectures based on their impacts on system reliability.

Standards demand that assurance cases support safety critical developments. It is widely acknowledged, however, that the current practice of post-hoc assurance-that the product is built and only then argued for safety-leads to many engineering process deficiencies, extra expense, and poorer products. This paper argues how the Problem Oriented Software Engineering framework can be used in the concurrent design of a safe product and its safety case, by which these deficiencies can be addressed. The basis of the paper is a real development, undertaken by the second author of this paper, of safety-related subsystems flying in real aircraft. The case study retains all essential detail and complexity.

Due to the complexity of the current software systems and the diversity of their architectural styles and component models, architecture-based reliability is becoming a more important quality requirement than ever before. Architecturebased reliability efforts depend on the behavior of individual components and their interactions with respect to their influences on the system reliability. Depending on different viewpoints and assumptions, a component takes various definitions and forms. As a result, numerous reliability works that involve varieties of the underlying strategies, objectives, and parameters are proposed for software architectures. Classifying these efforts is important for creating and selecting potential solutions that handle the reliability of software applications. In this paper, we provide a taxonomy of architecture-based reliability efforts. We classify these efforts according to the reliability goals, component abstraction, and level of granularity. We explain the existing techniques considering their assumptions with respect to these classification parameters and provide detailed description about the specific issues and considerations of each class.

Carbonate rocks from the Minia, Samalut, Maghagha, and Qarara localities were collected for geological and engineering research. The purpose of this study is to determine the suitability of these rocks for exploitation in the construction, aggregate, and chemical fields. The petrography, physical, and mechanical analyses show that the rock has the most suitable qualities for many uses in structural engineering fields and chemical plants. Samalut Formation carbonates are exceptionally pure. As a result, they are suitable for paper, paint, and other chemical industries, whereas carbonates from the Minia Formation are suitable for paint, cement, and building. Additionally, the Maghagha and Qarara Formations are appropriate for construction.