• Web Interface for Telescience
We developed a web-based system which enables mission scientists and planners to collaboratively plan and simulate Mars rover and lander missions over the Internet. The Web Interface for Telescience (WITS) was extended by Jet Propulsion Laboratory and selected for planning and control of the Robotic Arm and Surface Stereo Imager in the Mars Polar Lander (MPL) Mission. An adapted version of WITS, called Science Activity Planner, was used for science operations planning in the Mars Exploration Rover (MER) mission.
• Operator Interface for UAV Control
We developed an agent-based intelligent operator interface MIIIRO (Multi-Modal Immersive Intelligent Interface for Remote Operation) for controlling unmanned aerial vehicles in performing surveillance tasks. This interface accepts multimodal inputs, including joystick, head tracker and voice. An information mediator network is used to enable the coordination among the intelligent agents.
• Guarded Software Upgrading
We developed a methodology that is called onboard guarded software upgrading (GSU) for evolvable avionics systems. This methodology permits an upgraded software component to start its service to a long-life mission seamlessly through onboard validation and guarded operation; in the case that the upgraded component is not sufficiently reliable and thus imposes an unacceptable risk to the mission, the GSU framework ensures that the system will be safely downgraded back by replacing the upgraded software component with an earlier version, with minimal loss of mission performance.
• MDCD Error Containment and Recovery Protocol
The message-driven confidence-driven (MDCD) nature of this protocol makes it differ significantly from traditional software fault tolerance techniques for distributed computing. Most importantly, rather than prevent, by controlling and mediating the information flow, erroneous information from affecting a system component, the MDCD approach allows the interacting processes to talk to each other without restriction but keeps track of potential error contamination to enable recovery actions. This protocol has been prototyped in the GSU middleware.
• Software Rejuvenation for Distributed Applications
Inspired by the prior work and motivated by the fact that rapidly advancing network technologies have resulted in the reliance of an ever-increasing fraction of the world's infrastructure upon distributed software systems, we have developed a software rejuvenation framework for stateful distributed applications that comprise server replicas. The framework is constructed based on three building blocks, namely, a rejuvenation algorithm, a set of performability metrics, and a performability model. The building blocks collectively allow preventive maintenance to be carried out in stateful distributed systems, without causing operation disruption or violating eventual consistency.
• Failure Detection Services for Large-Scale Ad Hoc Wireless Network Applications
Ad hoc wireless networks are notoriously vulnerable to message loss, which precludes deterministic guarantees for the completeness and accuracy properties of failure detection services (FDS). To meet the challenges, we have developed an FDS based on the notion of clustering. Specifically, we use a cluster-based communication architecture to permit the FDS to be implemented in a distributed manner via intra-cluster heartbeat diffusion and to allow a failure report to be forwarded across clusters through the upper layer of the communication hierarchy. We extensively exploit the message redundancy that is inherent in ad hoc wireless settings to mitigate the effects of message loss on the accuracy and completeness properties of failure detection. As shown by quantitative analyses, the resulting FDS is able to provide satisfactory probabilistic guarantees for detection completeness and accuracy.
• Performability Modeling for Engineering Applications
We developed a model-translation approach that enables us to exploit reward model solution techniques which we would otherwise be unable to utilize for engineering applications. In particular, we transform the problem of solving a complex performability measure into that of evaluating several constituent reward variables, each of which can be easily mapped to a reward structure and thereby evaluated efficiently using any mathematical modeling tools that support reward model solutions.
• Distributed Information Integration
We developed a scalable, secure, open-system architecture for distributed information integration and intelligent information management. This architecture supports an integrated Navy shipboard information management system (INSIMS) that combines the existing Navy information systems that are distributed and heterogeneous in nature. We consider an information system as an information/service requester as well as an information/service provider. We model information/service requesters and providers with a domain model, which is developed using ontology technology, and connects the activities of the requesters and providers using wrapper middleware technology.
• Distributed Collaboration via Wireless Communications
We developed an infrastructure which enables multiple users to interact and collaborate on software applications remotely using their mobile devices. Multiuser collaboration is an important element of ground operations in planetary rover and lander missions. During mission operations, scientists need to meet often to plan science activities with planning and visualization tools projected on large displays. This infrastructure allows the scientists to interact directly with the software tools and collaborate on science planning activities.
• Risk Assessment and Management Environment
We developed a design-for-safety (DFS) workbench called Risk Assessment and Management Environment (RAME) for microelectronic avionics systems. Our objective is to transform DFS practice from an ad-hoc, inefficient, error-prone approach to a stringent engineering process such that DFS can keep up with the rapidly growing complexity of avionics systems. RAME is built upon an information infrastructure that comprises a test-reporting/failure-tracking system, an off-the-shelf data mining tool, a knowledge base, and a fault model. This infrastructure permits systematic learning from prior projects and enables the automation of failure mode, effect and criticality analysis (FMECA). Among other unique features, the most important advantage of RAME is its capability of directly accepting design source code in hardware description languages (HDLs) for automated failure mode analysis, which enables RAME to be compatible to and to evolve with most ECAD (electronic-computer-aided-design) systems.