3,420 research outputs found

    Space Station Freedom automation and robotics: An assessment of the potential for increased productivity

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    This report presents the results of a study performed in support of the Space Station Freedom Advanced Development Program, under the sponsorship of the Space Station Engineering (Code MT), Office of Space Flight. The study consisted of the collection, compilation, and analysis of lessons learned, crew time requirements, and other factors influencing the application of advanced automation and robotics, with emphasis on potential improvements in productivity. The lessons learned data collected were based primarily on Skylab, Spacelab, and other Space Shuttle experiences, consisting principally of interviews with current and former crew members and other NASA personnel with relevant experience. The objectives of this report are to present a summary of this data and its analysis, and to present conclusions regarding promising areas for the application of advanced automation and robotics technology to the Space Station Freedom and the potential benefits in terms of increased productivity. In this study, primary emphasis was placed on advanced automation technology because of its fairly extensive utilization within private industry including the aerospace sector. In contrast, other than the Remote Manipulator System (RMS), there has been relatively limited experience with advanced robotics technology applicable to the Space Station. This report should be used as a guide and is not intended to be used as a substitute for official Astronaut Office crew positions on specific issues

    Deep space network resource scheduling approach and application

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    Deep Space Network (DSN) resource scheduling is the process of distributing ground-based facilities to track multiple spacecraft. The Jet Propulsion Laboratory has carried out extensive research to find ways of automating this process in an effort to reduce time and manpower costs. This paper presents a resource-scheduling system entitled PLAN-IT with a description of its design philosophy. The PLAN-IT's current on-line usage and limitations in scheduling the resources of the DSN are discussed, along with potential enhancements for DSN application

    Adaptive Network Coding for Scheduling Real-time Traffic with Hard Deadlines

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    We study adaptive network coding (NC) for scheduling real-time traffic over a single-hop wireless network. To meet the hard deadlines of real-time traffic, it is critical to strike a balance between maximizing the throughput and minimizing the risk that the entire block of coded packets may not be decodable by the deadline. Thus motivated, we explore adaptive NC, where the block size is adapted based on the remaining time to the deadline, by casting this sequential block size adaptation problem as a finite-horizon Markov decision process. One interesting finding is that the optimal block size and its corresponding action space monotonically decrease as the deadline approaches, and the optimal block size is bounded by the "greedy" block size. These unique structures make it possible to narrow down the search space of dynamic programming, building on which we develop a monotonicity-based backward induction algorithm (MBIA) that can solve for the optimal block size in polynomial time. Since channel erasure probabilities would be time-varying in a mobile network, we further develop a joint real-time scheduling and channel learning scheme with adaptive NC that can adapt to channel dynamics. We also generalize the analysis to multiple flows with hard deadlines and long-term delivery ratio constraints, devise a low-complexity online scheduling algorithm integrated with the MBIA, and then establish its asymptotical throughput-optimality. In addition to analysis and simulation results, we perform high fidelity wireless emulation tests with real radio transmissions to demonstrate the feasibility of the MBIA in finding the optimal block size in real time.Comment: 11 pages, 13 figure

    Ethernet - a survey on its fields of application

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    During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

    Develop specifications for knowledge worker system, version 1.0

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    Issued as Monthly progress reports [nos. 1-2], Monthly status reports [nos. 1-7], and Reports [nos. 1-6], Project D-48-61

    PLAN-IT: Scheduling assistant for solar system exploration

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    A frame-based expert scheduling system shell, PLAN-IT, is developed for spacecraft scheduling in the Request Integration Phase, using the Comet Rendezvous Asteroid Flyby (CRAF) mission as a development base. Basic, structured, and expert scheduling techniques are reviewed. Data elements such as activity representation and resource conflict representation are discussed. Resource constraints include minimum and maximum separation times between activities, percentage of time pointed at specific targets, and separation time between targeted intervals of a given activity. The different scheduling technique categories and the rationale for their selection are also considered

    Extending Office 365 with Microsoft Azure

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    The topic of this thesis is extending Office 365 with cloud services offered by Microsoft Azure. The purpose of this thesis is to identify and present Azure services which can be used to extend Office 365 functionality. The most essential services and tools are covered from built-in services to custom solutions. In addition to Azure services, Office 365 application programming interfaces are also covered as they can be used with several extension scenarios. Both Office 365 and Azure are rapidly developing cloud platforms that are constantly transforming and offering new features. This thesis will compare cloud solutions to traditional on-premises solutions and will also cover a few upcoming Azure features that can be used to extend Office 365 in the future. Almost all Azure services can be used to extend Office 365 in some way but the study is focused on common Office 365 extension scenarios. General description of each Azure service is given, after which the use cases with Office 365 are specified. This thesis provides an overview on Office 365 extension with a modern cloud computing platform. The extension scenarios are sorted under three topics which describe the usage with Office 365. Several Azure services are covered on some extension scenarios, comparing the options to achieve the most suitable solution for the case. A more profound study is presented of a single specific Office 365 extension scenario.Tässä opinnäytetyössä tutkittiin Office 365 -tuoteperheen laajentamista Microsoftin Azure-pilvipalveluiden avulla. Tavoitteena opinnäytetyössä oli selvittää, mitä Azuren palveluita voidaan käyttää Office 365 -laajentamisessa. Tutkimus on rajattu kaikkein olennaisimpiin Azuren palveluihin. Työssä kuvataan laajennusmahdollisuuksia sisäänrakennetuista palveluista ja työkaluista räätälöityihin ratkaisuihin. Azuren palveluiden lisäksi opinnäytetyössä kuvataan Office 365 -rajapinnat, jotka liittyvät moneen käsiteltävään laajennustapaukseen. Sekä Office 365 että Azure ovat Microsoftin nopeasti kehittyviä pilvipalveluja, jotka muuttuvat koko ajan tarjoten uusia ominaisuuksia. Tämä opinnäytetyö vertaa pilviratkaisuja perinteisiin paikallisiin ratkaisuihin ja esittelee myös muutaman uuden Azure-palvelun, joita voidaan hyödyntää Office 365 -laajentamisessa tulevaisuudessa. Lähes jokaista Azuren palvelua voidaan jollakin tavalla hyödyntää Office 365 -kehityksessä, mutta tutkimuksessa pyrittiin löytämään ratkaisuja yleisimpiin Office 365 -laajennustapauksiin. tarkennetaan palveluun liittyvät Office 365 -käyttötapaukset sekä palvelun käyttö kehitystyössä. Opinnäytetyö antaa kokonaiskuvan Office 365 -laajentamisesta modernin pilvipalvelun kautta. Laajennustapaukset ovat jaoteltu työssä muutaman kokonaisuuden alle. Joidenkin tapausten kohdalla kuvataan useampi Azure-palvelu, joita vertailemalla saadaan selville tapaukseen parhaiten sopiva ratkaisu. Yhden laajentamistapauksen rakentaminen Azure-palvelun avulla kuvataan opinnäytetyössä tarkemmin

    A Concept for Robust, High Density Terminal Air Traffic Operations

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    This paper describes a concept for future high-density, terminal air traffic operations that has been developed by interpreting the Joint Planning and Development Office s vision for the Next Generation (NextGen) Air Transportation System and coupling it with emergent NASA and other technologies and procedures during the NextGen timeframe. The concept described in this paper includes five core capabilities: 1) Extended Terminal Area Routing, 2) Precision Scheduling Along Routes, 3) Merging and Spacing, 4) Tactical Separation, and 5) Off-Nominal Recovery. Gradual changes are introduced to the National Airspace System (NAS) by phased enhancements to the core capabilities in the form of increased levels of automation and decision support as well as targeted task delegation. NASA will be evaluating these conceptual technological enhancements in a series of human-in-the-loop simulations and will accelerate development of the most promising capabilities in cooperation with the FAA through the Efficient Flows Into Congested Airspace Research Transition Team

    An Integrated Control Framework for Long-Term Autonomy in Mobile Service Robots

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