Parallel Gesture Recognition with Soft Real-Time Guarantees

Using imperative programming to process event streams, such as those generated by multi-touch devices and 3D cameras, has significant engineering drawbacks. Declarative approaches solve common problems but so far, they have not been able to scale on multicore systems while providing guaranteed response times. We propose PARTE, a parallel scalable complex event processing engine that allows for a declarative definition of event patterns and provides soft real-time guarantees for their recognition. The proposed approach extends the classical Rete algorithm and maps event matching onto a graph of actor nodes. Using a tiered event matching model, PARTE provides upper bounds on the detection latency by relying on a combination of non-blocking message passing between Rete nodes and safe memory management techniques. The performance evaluation shows the scalability of our approach on up to 64 cores. Moreover, it indicates that PARTE's design choices lead to more predictable performance compared to a PARTE variant without soft real-time guarantees. Finally, the evaluation indicates further that gesture recognition can benefit from the exposed parallelism with superlinear speedups

Parallel Gesture Recognition with Soft Real-Time Guarantees

Applying imperative programming techniques to process event streams, like those generated by multi-touch devices and 3D cameras, has significant engineering drawbacks. Declarative approaches solve these problems but have not been able to scale on multicore systems while providing guaranteed response times. We propose PARTE, a parallel scalable complex event processing engine which allows a declarative definition of event patterns and provides soft real-time guarantees for their recognition. It extends the state-saving Rete algorithm and maps the event matching onto a graph of actor nodes. Using a tiered event matching model, PARTEprovides upper bounds on the detection latency. Based on the domain-specific constraints, PARTE's design relies on a combination of 1) lock-free data structures; 2) safe memory management techniques; and 3) message passing between Rete nodes. In our benchmarks, we measured scalability up to 8 cores, outperforming highly optimized sequential implementations

The 1990 Goddard Conference on Space Applications of Artificial Intelligence

The papers presented at the 1990 Goddard Conference on Space Applications of Artificial Intelligence are given. The purpose of this annual conference is to provide a forum in which current research and development directed at space applications of artificial intelligence can be presented and discussed. The proceedings fall into the following areas: Planning and Scheduling, Fault Monitoring/Diagnosis, Image Processing and Machine Vision, Robotics/Intelligent Control, Development Methodologies, Information Management, and Knowledge Acquisition

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area

Incipient fault detection study for advanced spacecraft systems

A feasibility study to investigate the application of vibration monitoring to the rotating machinery of planned NASA advanced spacecraft components is described. Factors investigated include: (1) special problems associated with small, high RPM machines; (2) application across multiple component types; (3) microgravity; (4) multiple fault types; (5) eight different analysis techniques including signature analysis, high frequency demodulation, cepstrum, clustering, amplitude analysis, and pattern recognition are compared; and (6) small sample statistical analysis is used to compare performance by computation of probability of detection and false alarm for an ensemble of repeated baseline and faulted tests. Both detection and classification performance are quantified. Vibration monitoring is shown to be an effective means of detecting the most important problem types for small, high RPM fans and pumps typical of those planned for the advanced spacecraft. A preliminary monitoring system design and implementation plan is presented

Aeronautical engineering: A continuing bibliography with indexes (supplement 217)

This bibliography lists 450 reports, articles, and other documents introduced into the NASA scientific and technical information system in August, 1987

Fifth Conference on Artificial Intelligence for Space Applications

The Fifth Conference on Artificial Intelligence for Space Applications brings together diverse technical and scientific work in order to help those who employ AI methods in space applications to identify common goals and to address issues of general interest in the AI community. Topics include the following: automation for Space Station; intelligent control, testing, and fault diagnosis; robotics and vision; planning and scheduling; simulation, modeling, and tutoring; development tools and automatic programming; knowledge representation and acquisition; and knowledge base/data base integration

Second Annual Workshop on Space Operations Automation and Robotics (SOAR 1988)

Papers presented at the Second Annual Workshop on Space Operation Automation and Robotics (SOAR '88), hosted by Wright State University at Dayton, Ohio, on July 20, 21, 22, and 23, 1988, are documented herein. During the 4 days, approximately 100 technical papers were presented by experts from NASA, the USAF, universities, and technical companies. Panel discussions on Human Factors, Artificial Intelligence, Robotics, and Space Systems were held but are not documented herein. Technical topics addressed included knowledge-based systems, human factors, and robotics

Circa: The Cooperatice Intelligent Real-Time Control Architecture

The Cooperative Intelligent Real-time Control Architecture (CIRCA) is a novel architecture for intelligent real-time control that can guarantee to meet hard deadlines while still using unpredictable, unrestricted AI methods. CIRCA includes a real-time subsystem used to execute reactive control plans that are guaranteed to meet the domain's real-time deadlines, keeping the system safe. At the same time, CIRCA's AI subsystem performs higher-level reasoning about the domain and the system's goals and capabilities, to develop future reactive control plans. CIRCA thus aims to be intelligent about real-time: rather than requiring the system's AI methods to meet deadlines, CIRCA isolates its reasoning about which time-critical reactions to guarantee from the actual execution of the se ected reactions. The formal basis for CIRCA's performance guarantees is a state-based world model of agent/environment interactions. Borrowing approaches from real-time systems research, the world model provides the information required to make real-time performance guarantees, but avoids unnecessary complexity. Using the world model, the AI subsystem develops reactive control plans that restrict the world to a limited set of safe and desirable states, by guaranteeing the timely performance of actions to preempt transitions that lead out of the set of states. By executing such "safe" and "stable" plans, CIRCA's real-time subsystem is able to keep the system safe (in the world as modeled) for an indeterminate amount of time, while the parallel AI subsystem develops the next appropriate plan. We have applied a prototype CIRCA implementation to a simulated Puma robot arm performing multiple tasks with real-time deadlines, such as packing parts off a conveyor belt and responding to asynchronous interrupts. Our experimental results show how the system can guarantee to accomplish these tasks under a given set of domain conditions (e.g., conveyor belt speed) and resource limitations (e.g., robot arm speed). Furthermore, because CIRCA reasons explicitly about its own predictable, guaranteed behaviors, the system can recognize when its resources are insufficient for the desired behaviors (e.g., parts are arriving too quickly to be packed carefully), and can then make principled modifications to its performance (e.g., temporarily stacking parts on a table) to maintain system safety. (Also cross-referenced as UMIACS-TR-93-104