Emil Vassev

Towards an ASSL specification model for NASA swarm-based exploration missions

NASA swarm-based exploration missions represent a new class of concept missions based on the cooperative nature of a hive culture. A mission of this class requires an autonomic system, comprising a set of autonomous mobile units. The design and implementation of such systems requires specific engineering approaches, including new formal specification methods and techniques. This article presents an introduction to our research towards a formal specification of NASA concept swarm-based missions. The Autonomic System Specification Language (ASSL) is a framework for formally specifying and generating autonomic systems. With ASSL, we can specify high-level behavior policies, as part of overall system behavior, which shows that ASSL is a very appropriate language for specifying the autonomic behavior of swarm-based missions. We show how ASSL can be used to specify self-configuring, self-healing, and safety properties of NASA swarm-based missions.

ASSL - Autonomic System Specification Language

This article is an overview of the Autonomic System Specification Language (ASSL). ASSL is a framework for formally specifying and generating autonomic systems. The latter are specified as formal executable models with an interaction protocol and autonomic elements. We explain in detail the architecture of the ASSL framework and demonstrate how to specify autonomic systems. In this paper, we do not talk about syntax and semantic aspects of ASSL, since these are going to be tackled by our ongoing research and described in other papers.

Modeling the Image-Processing Behavior of the NASA Voyager Mission with ASSL

NASA exploration missions increasingly rely on the concepts of autonomic computing, exploiting these to increase the survivability of remote missions, particularly when human tending is not feasible. This paper presents initial results of long-term research targeted at the design and implementation of prototype models for future Voyager-like missions that rely on principles of autonomic computing. Here, we employ the Autonomic System Specification Language (ASSL) to build a formal model and to generate a prototype for the image-processing behavior of the NASA Voyager Mission. This helps to validate existing features and perform experiments through simulation. Moreover, this prototype lays the basis for future experiments whereby autonomic features are added in a stepwise manner.

The Challenge of Developing Autonomic Systems

In this paper, autonomic systems are discussed. The rapidly growing field of autonomic computing promises a new approach to developing complex computing systems. Different implementations of awareness for intelligent systems can prove useful in developing autonomic systems such as commercially available server monitoring platforms.

Autonomy requirements engineering: a case study on the BepiColombo mission

The development of unmanned space exploration missions is closely related to integration and promotion of autonomy in robotic spacecraft. Elicitation and expression of autonomy requirements is one of the most significant challenges the autonomous spacecraft engineers need to overcome. Nowadays, requirements engineering for autonomous systems appears to be a wide open research area with no definitive solution yet. This paper presents an approach to Autonomy Requirements Engineering where Goal-Oriented Requirements Engineering is merged with special Generic Autonomy Requirements. To provide a solution to the domain of space missions, the Generic Autonomy Requirements are put in the context of space missions. Further, the approach is applied to a case study based on the ESAs BepiColombo Mission where missions autonomy requirements are elicited.

Knowledge representation for self-adaptive behavior

An autonomic system is considered to be a self-adaptive system that changes its behavior in response to stimuli from its execution and operational environment. Such behavior is considered autonomic and self-adaptive and is intended to drive intelligent systems in situations requiring adaptation. Such systems encapsulate rules, constraints and mechanisms for self-adaptation and acquire and process knowledge about themselves and their environment. In this paper, an approach to knowledge representation and reasoning for self-adaptive behavior is presented. The approach is formal and demonstrates how knowledge representation and reasoning help to establish the vital connection between knowledge, perception, and actions realizing the self-adaptive behavior. The knowledge is used against the perception of the world to generate appropriate actions in compliance to some goals and beliefs.

Swarm Technology at NASA: Building Resilient Systems

Developing space systems is a complex task, driven by standards and safety requirements to ensure reliability of sophisticated hardware and software. Future NASA missions will focus on the development of swarm-based spacecraft systems comprising multiple self-organizing and autonomous spacecraft.

On the autonomy requirements for space missions

In new space exploration initiatives of NASA and ESA, there is emphasis on both human and robotic exploration. Risk and feasibility are major factors supporting the use of unmanned craft and the use of automation and robotic technologies where possible. In that context, an autonomous system is able to monitor its behavior and eventually modify the same according to changes in the operational environment, thus being considered as self-adaption. Requirements engineering for autonomous systems, therefore, must address what adaptations are possible and under what constrains, and how those adaptations are realized. Requirements engineering for autonomous systems appears to be a wide open research area with only a limited number of approaches yet considered. In this paper, we present initial results of our research and study on autonomy requirements for space systems.

Knowledge Representation and Awareness in Autonomic Service-Component Ensembles - State of the Art

Knowledge is the source of intelligence and both knowledge representation and knowledge management are crucial for intelligent systems. Well employed knowledge helps such systems become aware of situations, recognize states and eventually respond to changes. This paper presents our vision of knowledge representation and awareness in mobile swarm systems formed as open-ended ensembles of special autonomic components. Such components encapsulate rules, constraints and mechanisms for self-management and acquire and process knowledge about themselves, other service components and their environment. In this paper, we present our approach to high-level model of structured knowledge and a formal model of awareness in such autonomic service-component ensembles.

Towards Autonomic Specification of Distributed MARF with ASSL: Self-healing

In this paper, we discuss our work towards self-healing property specification of an autonomic behavior in the Distributed Modular Audio Recognition Framework (DMARF) by using the Autonomic System Specification Language (ASSL). ASSL aids in enhancing DMARF with an autonomic middleware that enables it to perform in autonomous systems that theoretically require less-to-none human intervention. Here, we add an autonomic middleware layer to DMARF by specifying the core four stages of the DMARF’s pattern-recognition pipeline as autonomic elements managed by a distinct autonomic manager. We devise the algorithms corresponding to this specification.