4,868 research outputs found

    Implementing and Evaluating Jukebox Schedulers Using JukeTools

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    Scheduling jukebox resources is important to build efficient and flexible hierarchical storage systems. JukeTools is a toolbox that helps in the complex tasks of implementing and evaluating jukebox schedulers. It allows the fast development of jukebox schedulers. The schedulers can be tested in numerous environments, both real and simulated types. JukeTools helps the developer to easily detect errors in the schedules. Analyzer tools create detailed reports on the behavior and performance of any of the scheduler, and provide comparisons between different schedulers. This paper describes the functionality offered by JukeTools, with special emphasis on how the toolbox can be used to develop jukebox schedulers

    Understanding the Computational Requirements of Virtualized Baseband Units using a Programmable Cloud Radio Access Network Testbed

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    Cloud Radio Access Network (C-RAN) is emerging as a transformative architecture for the next generation of mobile cellular networks. In C-RAN, the Baseband Unit (BBU) is decoupled from the Base Station (BS) and consolidated in a centralized processing center. While the potential benefits of C-RAN have been studied extensively from the theoretical perspective, there are only a few works that address the system implementation issues and characterize the computational requirements of the virtualized BBU. In this paper, a programmable C-RAN testbed is presented where the BBU is virtualized using the OpenAirInterface (OAI) software platform, and the eNodeB and User Equipment (UEs) are implemented using USRP boards. Extensive experiments have been performed in a FDD downlink LTE emulation system to characterize the performance and computing resource consumption of the BBU under various conditions. It is shown that the processing time and CPU utilization of the BBU increase with the channel resources and with the Modulation and Coding Scheme (MCS) index, and that the CPU utilization percentage can be well approximated as a linear increasing function of the maximum downlink data rate. These results provide real-world insights into the characteristics of the BBU in terms of computing resource and power consumption, which may serve as inputs for the design of efficient resource-provisioning and allocation strategies in C-RAN systems.Comment: In Proceedings of the IEEE International Conference on Autonomic Computing (ICAC), July 201

    Role of IAC in large space systems thermal analysis

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    Computer analysis programs to evaluate critical coupling effects that can significantly influence spacecraft system performance are described. These coupling effects arise from the varied parameters of the spacecraft systems, environments, and forcing functions associated with disciplines such as thermal, structures, and controls. Adverse effects can be expected to significantly impact system design aspects such as structural integrity, controllability, and mission performance. One such needed design analysis capability is a software system that can integrate individual discipline computer codes into a highly user-oriented/interactive-graphics-based analysis capability. The integrated analysis capability (IAC) system can be viewed as: a core framework system which serves as an integrating base whereby users can readily add desired analysis modules and as a self-contained interdisciplinary system analysis capability having a specific set of fully integrated multidisciplinary analysis programs that deal with the coupling of thermal, structures, controls, antenna radiation performance, and instrument optical performance disciplines

    Aircraft electromagnetic compatibility

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    Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting

    Near real-time analysis of active distribution networks in a Digital Twin framework. A real case study

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    The growth of distributed generation and the need of increasing Distribution Network (DN) resilience is encouraging Distribution System Operators (DSO) to increase awareness about the real-time status of the network as well as to actively manage flexible energy resources for improving system performances. In this context, Digital Twin (DT) is an enabling technology for a low-cost distributed framework that supports DN management. DT in the power system can be exploited taking advantage of the successful experiences in other sectors (e.g., smart manufacturing and building automation). This article presents a real case study of a DT development and its integration with an existing DN. The DT system architecture is based on the recent standards whilst main DT components have been originally developed, enabling near real-time services such as data collection, state estimation, and flexibility calculator. The individual performances of the integrated tools and the reliability of DT were tested and validated during one month of continuous operation. During the operation, good service continuity and accuracy performances were reported. Results from the flexibility calculator show the effectiveness of the proposed strategies that can improve the energy efficiency of the DN by increasing local self-consumption of Renewable Energy Sources (RES) production

    Advancing Protocol Diversity in Network Security Monitoring

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    With information technology entering new fields and levels of deployment, e.g., in areas of energy, mobility, and production, network security monitoring needs to be able to cope with those environments and their evolution. However, state-of-the-art Network Security Monitors (NSMs) typically lack the necessary flexibility to handle the diversity of the packet-oriented layers below the abstraction of TCP/IP connections. In this work, we advance the software architecture of a network security monitor to facilitate the flexible integration of lower-layer protocol dissectors while maintaining required performance levels. We proceed in three steps: First, we identify the challenges for modular packet-level analysis, present a refined NSM architecture to address them and specify requirements for its implementation. Second, we evaluate the performance of data structures to be used for protocol dispatching, implement the proposed design into the popular open-source NSM Zeek and assess its impact on the monitor performance. Our experiments show that hash-based data structures for dispatching introduce a significant overhead while array-based approaches qualify for practical application. Finally, we demonstrate the benefits of the proposed architecture and implementation by migrating Zeek\u27s previously hard-coded stack of link and internet layer protocols to the new interface. Furthermore, we implement dissectors for non-IP based industrial communication protocols and leverage them to realize attack detection strategies from recent applied research. We integrate the proposed architecture into the Zeek open-source project and publish the implementation to support the scientific community as well as practitioners, promoting the transfer of research into practice
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