1,093,972 research outputs found

    Shuttle Ku-band and S-band communications implementation study

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    Various aspects of the shuttle orbiter S-band network communication system, the S-band payload communication system, and the Ku-band communication system are considered. A method is proposed for obtaining more accurate S-band antenna patterns of the actual shuttle orbiter vehicle during flight because the preliminary antenna patterns using mock-ups are not realistic that they do not include the effects of additional appendages such as wings and tail structures. The Ku-band communication system is discussed especially the TDRS antenna pointing accuracy with respect to the orbiter and the modifications required and resulting performance characteristics of the convolutionally encoded high data rate return link to maintain bit synchronizer lock on the ground. The TDRS user constraints on data bit clock jitter and data asymmetry on unbalanced QPSK with noisy phase references are included. The S-band payload communication system study is outlined including the advantages and experimental results of a peak regulator design built and evaluated by Axiomatrix for the bent-pipe link versus the existing RMS-type regulator. The nominal sweep rate for the deep-space transponder of 250 Hz/s, and effects of phase noise on the performance of a communication system are analyzed

    Many-Task Computing and Blue Waters

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    This report discusses many-task computing (MTC) generically and in the context of the proposed Blue Waters systems, which is planned to be the largest NSF-funded supercomputer when it begins production use in 2012. The aim of this report is to inform the BW project about MTC, including understanding aspects of MTC applications that can be used to characterize the domain and understanding the implications of these aspects to middleware and policies. Many MTC applications do not neatly fit the stereotypes of high-performance computing (HPC) or high-throughput computing (HTC) applications. Like HTC applications, by definition MTC applications are structured as graphs of discrete tasks, with explicit input and output dependencies forming the graph edges. However, MTC applications have significant features that distinguish them from typical HTC applications. In particular, different engineering constraints for hardware and software must be met in order to support these applications. HTC applications have traditionally run on platforms such as grids and clusters, through either workflow systems or parallel programming systems. MTC applications, in contrast, will often demand a short time to solution, may be communication intensive or data intensive, and may comprise very short tasks. Therefore, hardware and software for MTC must be engineered to support the additional communication and I/O and must minimize task dispatch overheads. The hardware of large-scale HPC systems, with its high degree of parallelism and support for intensive communication, is well suited for MTC applications. However, HPC systems often lack a dynamic resource-provisioning feature, are not ideal for task communication via the file system, and have an I/O system that is not optimized for MTC-style applications. Hence, additional software support is likely to be required to gain full benefit from the HPC hardware

    Enhancement of microgrid operation by considering the cascaded impact of communication delay on system stability and power management

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    Power management, system stability and communication structure are three key aspects of microgrids (MGs) that have been explored in many research studies. However, the cascaded effect of communication structure on system stability followed by the impact of stability on the power management has not been fully explored in the literature yet and needs more attention. This paper not only explores this cascaded impact, but also provides a comprehensive platform to optimally consider three layers of MG design and operation from this perspective. For generation cost minimization and stability assessment, the proposed platform uses an adaptive particle swarm optimization (PSO) while a new class of data exchange scheme based on IEC 61850 protocol is proposed to reduce the communication time delays among the inverters of distributed generations and the MG control center. This paper also considers the system stability using small-signal model of a MG in a real-time manner as an embedded function in the PSO. In this context investigations have been conducted by modeling an isolated MG with solar farm, fuel cell generator and micro-turbine in MATLAB Simulink. Detailed simulation results indicate the proposed power and stability management method effectively reduces the MG generation cost through maximizing the utilization of the available renewable generations while considering system stability. © 2020 Elsevier Lt

    Cyber-physical framework for emulating distributed control systems in smart grids

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    This paper proposes a cyber-physical framework for investigating distributed control systems operating in the context of smart-grid applications. At the moment, the literature focuses almost exclusively on the theoretical aspects of distributed intelligence in the smart-grid, meanwhile, approaches for testing and validating such systems are either missing or are very limited in their scope. Three aspects need to be taken into account while considering these applications: (1) the physical system, (2) the distributed computation platform, and (3) the communication system. In most of the previous works either the communication system is neglected or oversimplified, either the distributed computation aspect is disregarded, either both elements are missing. In order to cover all these aspects, we propose a framework which is built around a fleet of low-cost single board computers coupled with a real-time simulator. Additionally, using traffic control and network emulation, the flow of data between different controllers is shaped so that it replicates various quality of service (QoS) conditions. The versatility of the proposed framework is shown on a study case in which 27 controllers self-coordinate in order to solve the distributed optimal power flow (OPF) algorithm in a dc network

    Co-Optimization of Communication, Motion and Sensing in Mobile Robotic Operations

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    In recent years, there has been considerable interest in wireless sensor networks and networked robotic systems. In order to achieve the full potential of such systems, integrative approaches that design the communication, navigation and sensing aspects of the systems simultaneously are needed. However, most of the existing work in the control and robotic communities uses over-simplified disk models or path-loss-only models to characterize the communication in the network, while most of the work in networkingand communication communities does not fully explore the benefits of motion.This dissertation thus focuses on co-optimizing these three aspects simultaneously in realistic communication environments that experience path loss, shadowing and multi-path fading. We show how to integrate the probabilistic channel prediction framework, which allows the robots to predict the channel quality at unvisited locations, into the co-optimization design. In particular, we consider four different scenarios: 1) robotic routerformation, 2) communication and motion energy co-optimization along a pre-defined trajectory, 3) communication and motion energy co-optimization with trajectory planning, and 4) clustering and path planning strategies for robotic data collection. Our theoretical, simulation and experimental results show that the proposed framework considerably outperforms the cases where the communication, motion and sensing aspects of the system are optimized separately, indicating the necessity of co-optimization. They furthershow the significant benefits of using realistic channel models, as compared to the case of using over-simplified disk models

    Building Integrated Remote Control Systems for Electronics Boards

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    This paper addresses several aspects of implementing a remote control system for a large number of electronics boards in order to perform remote Field Programmable Gate Array (FPGA) programming, hardware configuration, data register access, and monitoring, as well as interfacing it to an expert system. The paper presents a common strategy for the representation of the boards in the abstraction layer of the control system, and generic communication protocols for the access to the board resources. In addition, an implementation is proposed in which the mapping between the functional parameters and the physical registers of the different boards is represented by descriptors in the board representation such that the translation can be handled automatically by a generic translation manager. Using the Distributed Information Management (DIM) package for the control communication with the boards, and the industry SCADA system PVSS II from ETM, a complete control system has been built for the Timing and Fast Control (TFC) system of the LHCb experiment at CERN. It has been in use during the entire prototyping of the TFC system and the developments of the LHCb sub-detector electronics, and is now installed in the online system of the final experiment

    Algorithmic analysis and hardware implementation of a two-wire-interface communication analyser

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    This paper discusses the development of an algorithm for the data analysis to monitor Two-Wire-Interface operation in order to improve the reliability of communication. This algorithm is designed to improve code-efficiency with regards to hardware modelling. An algorithm for the protocol used in the Standard-Mode, Fast-Mode, Fast-Mode Plus and High-Speed-Mode was developed. The proposed algorithm has been derived using the bus protocol specification and implemented in hardware via a hardware description language. The correct operation of the algorithm was proofed by applying the hardware system on a sample communication. The paper also describes the development process of embedded systems and provides information on aspects regarding hardware modelling including a mathematical description of the TWI protocol is provided

    Research of computerization and implementation of the E-prescription for individual pharmacies

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    The paper deals with establishment, implementation and development of electronic prescription or e-Prescription in context with e-Health solutions. It includes introduction of a numerous innovative solutions, which are to be committed for data information flow, data management and functionality as well as of establishment of a new feasible communication forms between doctors, patients and pharmacists. The aim of the study is to describe some technical aspects and functionality of implementation of e-Prescription system for medical institutions, patients and pharmacies; and, calculation of the total cost of implementation (TCI) for Latvian individual pharmacies. Several expecting financial aspects, which have encompassed evaluation of TCI, calculating payback time, ROI, NPV, and IRR are to be calculated. On the bases of these financial calculations, the primary investment of implementation of e-Prescription for individual pharmacies and initial costs are determined. Impact on individual parts of TCI with the scope to individual pharmacy size, location, existence or absence of formal information strategy has calculated. According to collected data, research paper shows how proposed electronic system is going to implement among Latvian individual pharmacies.publishersversionPeer reviewe
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