Developing Experimental Models for NASA Missions with ASSL

NASA's new age of space exploration augurs great promise for deep space exploration missions whereby spacecraft should be independent, autonomous, and smart. Nowadays NASA increasingly relies on the concepts of autonomic computing, exploiting these to increase the survivability of remote missions, particularly when human tending is not feasible. Autonomic computing has been recognized as a promising approach to the development of self-managing spacecraft systems that employ onboard intelligence and rely less on control links. The Autonomic System Specification Language (ASSL) is a framework for formally specifying and generating autonomic systems. As part of long-term research targeted at the development of models for space exploration missions that rely on principles of autonomic computing, we have employed ASSL to develop formal models and generate functional prototypes for NASA missions. This helps to validate features and perform experiments through simulation. Here, we discuss our work on developing such missions with ASSL.Comment: 7 pages, 4 figures, Workshop on Formal Methods for Aerospace (FMA'09

General architecture for demand migration in the GIPSY demand-driven execution engine

During the conceptual design stage of a building, the design team often has to make critical decisions with significant impact on energy performance and indoor comfort conditions. The design and selection of fenestration systems and their control plays a key role in determining building performance, especially for perimeter spaces of commercial buildings. The domains of heating, cooling and lighting are closely related. An integrated thermal and daylighting approach is required for investigating the interactions between the different building systems. Advanced building simulation software can be used to evaluate overall building performance for specific fenestration schemes. However, these tools cannot provide information on how to select near-optimal design solutions from a large set of alternatives, since they require detailed input data which are not yet available at the early design stage. Therefore the selection of final design solutions concerning fenestration often involves many subjective factors. In this Thesis, a general and systematic simulation-based methodology for integrated daylighting and thermal analysis of facades and perimeter spaces of commercial buildings during the early design stage is presented. Using a systems integration approach, major dynamic links between thermal and daylighting performance are identified and used as design variables in a coupled thermal and daylighting simulation program. Integrated performance-based indices, generated from the continuous interaction between daylighting and thermal simulation, are calculated as a function of key linking parameters for investigating the balance between daylighting benefits and energy performance. The variation of these measures allows extraction of critical information for selection of window-to-wall ratio, shading device properties and control plus electric lighting control strategies. Maximization of daylight utilization, reduction in peak loads and energy demand for heating, cooling and lighting are used as criteria. The methodology is general and can be applied to any type of façade, location, orientation, glazing type and shading options. Results presented for perimeter offices in Montreal provide guidelines for selecting window-to-wall ratio for unobstructed façades, as well as recommendations for choosing shading device properties and control in conjunction with electric lighting operatio

Towards a Self-Forensics Property in the ASSL Toolset

This preliminary conceptual work discusses a notion of self-forensics as an autonomic property to augment the Autonomic System Specification Language (ASSL) framework of formal specification tools for autonomic systems. The core of the proposed methodology leverages existing designs, theoretical results, and implementing systems to enable rapid completion of and validation of the experiments and their the results initiated in this work. Specifically, we leverage the ASSL toolkit to add the self-forensics autonomic property (SFAP) to enable generation of the Java-based Object-Oriented Intensional Programming (JOOIP) language code laced with traces of Forensic Lucid to encode contextual forensic evidence and other expressions