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S&K Electronics;
"... Manned missions to other planetary bodies will rely heavily on robotics and automation to enhance the operational safety and capabilities of the crew. In particular, the movement and sensing capabilities of humans in spacesuits are severely constrained. Thus, an important class of robot will be thos ..."
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Cited by 15 (1 self)
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Manned missions to other planetary bodies will rely heavily on robotics and automation to enhance the operational safety and capabilities of the crew. In particular, the movement and sensing capabilities of humans in spacesuits are severely constrained. Thus, an important class of robot will be those that accompany humans during extra-vehicular activity (EVA) and provide assistance-- tool transport, video documentation, sample collection, etc. In 1999, NASA engaged in a set of field tests in California called ASRO (AStronaut-ROver), in which a space-suited test subject collaborated with the tele-operated Marsokhod mobile robot, controlled by scientist at a remote location. From the lessons learned in the ASRO tests, the EVA Robotic Assistant project was started at NASA’s Johnson Space Center to provide a testbed for continued research in astronaut-robot interaction and cooperation. In September 2000, NASA conducted two weeks of field tests in Arizona at three planetary surface analog sites. Three scenarios were tested requiring cooperation between a space-suited astronaut and the autonomous EVA Robotic Assistant: "Power Cable Deployment", "Solar Panel Deployment", and "Geologist's Assistant". In this paper, we describe the ERA project in detail, and report on results from the Arizona field tests.
Towards Real-time Fault-Tolerant CORBA Middleware
, 2002
"... An increasing number of applications are being developed using distributed object computing (DOC) middleware, such as CORBA. Many of these applications require the underlying middleware, operating systems, and networks to provide dependable end-to-end quality of service (QoS) support to enhance thei ..."
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Cited by 14 (3 self)
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An increasing number of applications are being developed using distributed object computing (DOC) middleware, such as CORBA. Many of these applications require the underlying middleware, operating systems, and networks to provide dependable end-to-end quality of service (QoS) support to enhance their efficiency, predictability, scalability, and reliability. The Object Management Group (OMG), which standardizes CORBA, has addressed many of these application requirements individually in the Real-time CORBA (RT-CORBA) and Fault-tolerant CORBA (FT-CORBA) specifications. Though the implementations of RT-CORBA are suitable for missioncritical commercial or military distributed real-time and embedded (DRE) systems, the usage of FT-CORBA with RTCORBA implementations are not yet suitable for systems that have stringent simultaneous dependability and predictability requirements.
Evaluating Policies and Mechanisms to Support Distributed Real-Time Applications with CORBA
, 2001
"... To be an effective platform for performance-sensitive realtime systems, commodity-off-the-shelf (COTS) distributed object computing (DOC) middleware must support application quality of service (QoS) requirements end-to-end. However, conventional COTS DOC middleware does not provide this support, whi ..."
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Cited by 14 (5 self)
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To be an effective platform for performance-sensitive realtime systems, commodity-off-the-shelf (COTS) distributed object computing (DOC) middleware must support application quality of service (QoS) requirements end-to-end. However, conventional COTS DOC middleware does not provide this support, which makes it unsuited for applications with stringent latency, determinism, and priority preservation requirements. It is essential, therefore, to develop standards-based, COTS DOC middleware that permits the specification, allocation, and enforcement of application QoS requirements end-to-end. The Real-time
FC-ORB: A robust distributed real-time embedded middleware with end-to-end utilization control
, 2006
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Enhancing the Robustness of Distributed Real-Time Middleware via End-to-End Utilization Control
- in RTSS ’05: Proceedings of the 26th IEEE International Real-Time Systems Symposium
, 2005
"... A key challenge for distributed real-time and embedded (DRE) middleware is maintaining both system reliability and desired real-time performance in unpredictable environments where system workload and resources may fluctuate significantly. This paper presents FC-ORB, a realtime Object Request Broker ..."
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Cited by 12 (11 self)
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A key challenge for distributed real-time and embedded (DRE) middleware is maintaining both system reliability and desired real-time performance in unpredictable environments where system workload and resources may fluctuate significantly. This paper presents FC-ORB, a realtime Object Request Broker (ORB) middleware that employs end-to-end utilization control to handle fluctuations in application workload and system resources. The contributions of this paper are three-fold. First, we present a novel utilization control service that enforces desired CPU utilization bounds on multiple processors by adapting the rates of end-to-end tasks within user-specified ranges. Second, we describe a set of middleware-level mechanisms designed to support end-to-end tasks and distributed multi-processor utilization control in a real-time ORB. Finally, we present extensive experimental results on a Linux testbed. Our results demonstrate that our middleware can maintain desired utilizations in face of uncertainties and variations in task execution times, resource contentions from external workloads, and permanent processor failure. FC-ORB demonstrates that the integration of utilization control, end-to-end scheduling and fault-tolerance mechanisms in DRE middleware is a promising approach for enhancing the robustness of DRE applications in unpredictable environments. 1
DyKnow: An Approach to Middleware for Knowledge Processing
, 2004
"... Any autonomous system embedded in a dynamic and changing environment must be able to create qualitative knowledge and object structures representing aspects of its environment on the fly from raw or preprocessed sensor data in order to reason qualitatively about the environment. These structures mus ..."
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Cited by 12 (12 self)
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Any autonomous system embedded in a dynamic and changing environment must be able to create qualitative knowledge and object structures representing aspects of its environment on the fly from raw or preprocessed sensor data in order to reason qualitatively about the environment. These structures must be managed and made accessible to deliberative and reactive functionalities which are dependent on being situationally aware of the changes in both the robotic agent's embedding and internal environment. DyKnow is a software framework which provides a set of functionalities for contextually accessing, storing, creating and processing such structures. The system is implemented and has been deployed in a deliberative /reactive architecture for an autonomous unmanned aerial vehicle. The architecture itself is distributed and uses real-time CORBA as a communications infrastructure. We describe the system and show how it can be used in execution monitoring and chronicle recognition scenarios for UAV applications.
Automating component-based system assembly
- IN PROCEEDINGS OF THE 2007 INTERNATIONAL SYMPOSIUM ON SOFTWARE TESTING AND ANALYSIS (ISSTA ’07
, 2007
"... One of the major challenges in the development of large component-based software systems is the system assembly problem: from a sea of available components, which should be selected and how should they be connected, integrated, and assembled so that the overall system requirements are satisfied? We ..."
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Cited by 10 (3 self)
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One of the major challenges in the development of large component-based software systems is the system assembly problem: from a sea of available components, which should be selected and how should they be connected, integrated, and assembled so that the overall system requirements are satisfied? We present a powerful framework for automatically solving the system assembly problem directly from system requirements. Our framework includes an expressive language for declaratively describing system-level requirements, including component interfaces and dependencies, resource requirements, safety properties, objective functions, and various types of constraints. We show how to automatically solve system assembly problems using verification technology that takes advantage of current advances in Boolean satisfiability methods. We have implemented our techniques in the CoBaSA tool (Component-Based System Assembly), and we have successfully applied it to several large-scale industrial examples.
Evaluating and Optimizing Thread Pool Strategies for Real-Time CORBA
- Proc. of the ACM SIGPLAN Workshop on Language, Compiler and Tool Support for Embedded Systems
, 2000
"... Strict control over the scheduling and execution of processor resources is essential for many fixed-priority real-time applications. To facilitate this common requirement, the Real-Time CORBA (RT-CORBA) specification defines standard middleware features that support end-to-end predictability for ope ..."
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Cited by 10 (0 self)
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Strict control over the scheduling and execution of processor resources is essential for many fixed-priority real-time applications. To facilitate this common requirement, the Real-Time CORBA (RT-CORBA) specification defines standard middleware features that support end-to-end predictability for operations in such applications. One of the most important features in RT-CORBA is thread pools, which allow application developers and end-users to configure and control processor resources. This paper provides two contributions to the evaluation of techniques for improving the quality of implementation of RTCORBA thread pools. First, we describe the key patterns underlying common strategies for implementing RT-CORBA thread pools. Second, we evaluate each thread pool strategy in terms of its consequences on (1) feature support, such as request buffering and thread borrowing, (2) scalability in terms of endpoints and event demultiplexers required, (3) efficiency in terms of data movement, context switches, memory allocations, and synchronizations required, (4) optimizations in terms of stack and thread specific storage memory allocations, and (5) bounded and unbounded priority inversion incurred in each implementation. This paper also provides results that illustrate empirically how different thread pool implementation strategies perform in different ORB configurations. 1
Research Advances in Middleware for Distributed Systems: State of the Art
, 2002
"... this paper, we can do little more than summarize and lend perspective to the many activities, past and present, that contribute to making DOC middleware technology an area of exciting current development, along with considerable opportunity and unsolved challenging problems. We have provided many re ..."
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Cited by 10 (1 self)
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this paper, we can do little more than summarize and lend perspective to the many activities, past and present, that contribute to making DOC middleware technology an area of exciting current development, along with considerable opportunity and unsolved challenging problems. We have provided many references to other sources to obtain additional information about ongoing activities in this area. We have also provided a more detailed discussion and organization for a collection of activities that we believe represent the most promising future R&D 33 directions of middleware for large-scale, network-centric systems. Downstream, the goals of these R&D activities are to: 1. Reliably and repeatably construct and compose network-centric systems that can meet and adapt to more diverse, changing requirements/environments and 2. Enable the affordable construction and composition of the large numbers of these systems that society will demand, each precisely tailored to specific domains
A Time-Triggered Ethernet Protocol for Real-Time CORBA
, 2002
"... The Real-Time CORBA and minimumCORBA specifications are important steps towards defining standard-based middleware which can satisfy real-time requirements in an embedded system. These real-time middlewares must be based on a real-time operating system (RTOS) and a real-time network. This article pr ..."
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Cited by 9 (1 self)
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The Real-Time CORBA and minimumCORBA specifications are important steps towards defining standard-based middleware which can satisfy real-time requirements in an embedded system. These real-time middlewares must be based on a real-time operating system (RTOS) and a real-time network. This article presents a new timetriggered ethernet protocol that has been implemented under RTLinux. Furthermore it describes a Real-Time CORBA implementation called ROFES, which is based on this new real-time network.
