18,591 research outputs found

    Modeling and Simulation of a University LAN in OPNET Modeller Environment

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    Academia has peculiar networking needs that must be satisfied for effective dissemination of knowledge. The main purpose of a campus network is efficient resource sharing and access to information among its users. A key issue with designing and implementing such Local Area Networks (LAN) is its performance under ever increasing network traffic, and how this is affected by various network metrics such as latency and end-to-end delay. Implementation of network systems is a complex and expensive task; hence network simulation has become essential and has proven to be cost effective and highly useful for modeling the desired characteristics and analyzing performance under different scenarios. As well as providing useful prognosis of future network performance based on current expansion dynamics. We present in this paper the simulation and analysis of the Covenant University campus LAN in the OPNET Modeler environment

    Data Acquisition and Control System of Hydroelectric Power Plant Using Internet Techniques

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    VodnĂ­ energie se nynĂ­ stala nejlepĆĄĂ­m zdrojem elektrickĂ© energie na zemi. VyrĂĄbĂ­ se pomocĂ­ energie poskytovanĂ© pohybem nebo pĂĄdem vody. Historie dokazuje, ĆŸe nĂĄklady na tuto elektrickou energii zĆŻstĂĄvajĂ­ konstantnĂ­ v prĆŻběhu celĂ©ho roku. Vzhledem k mnoha vĂœhodĂĄm, větĆĄina zemĂ­ nynĂ­ vyuĆŸĂ­vĂĄ vodnĂ­ energie jako hlavnĂ­ zdroj pro vĂœrobu elektrickĂ© energie.NejdĆŻleĆŸitějĆĄĂ­ vĂœhodou je, ĆŸe vodnĂ­ energie je zelenĂĄ energie, coĆŸ znamenĂĄ, ĆŸe ĆŸĂĄdnĂ© vzduĆĄnĂ© nebo vodnĂ­ znečiĆĄĆ„ujĂ­cĂ­ lĂĄtky nejsou vyrĂĄběny, takĂ© ĆŸĂĄdnĂ© sklenĂ­kovĂ© plyny jako oxid uhličitĂœ nejsou vyrĂĄběny, coĆŸ činĂ­ tento zdroj energie ĆĄetrnĂœ k ĆŸivotnĂ­mu prostƙedĂ­. A tak brĂĄnĂ­ nebezpečí globĂĄlnĂ­ho oteplovĂĄnĂ­. PouĆŸitĂ­ internetovĂ© techniky k ovladĂĄnĂ­ několika vodnĂ­ch elektrĂĄren mĂĄ velmi vĂœznamnĂ© vĂœhody, jako snĂ­ĆŸenĂ­ provoznĂ­ch nĂĄkladĆŻ a flexibilitu uspokojenĂ­ změny poptĂĄvky po energii na straně spotƙeby. TakĂ© velmi efektivně čelĂ­ velkĂœm naruĆĄenĂ­m elektrickĂ© sĂ­tě, jako je napƙíklad pƙidĂĄnĂ­ nebo odebrĂĄnĂ­ velkĂ© zĂĄtÄ›ĆŸe, a poruch. Na druhou stranu, systĂ©m zĂ­skĂĄvĂĄnĂ­ dat poskytuje velmi uĆŸitečnĂ© informace pro typickĂ© i vědeckĂ© analĂœzy, jako jsou ekonomickĂ© nĂĄklady, predikce poruchy systĂ©mĆŻ, predikce poptĂĄvky, plĂĄny ĂșdrĆŸby, systĂ©mĆŻ pro podporu rozhodovĂĄnĂ­ a mnoho dalĆĄĂ­ch vĂœhod. Tato prĂĄce popisuje vĆĄeobecnĂœ model, kterĂœ mĆŻĆŸe bĂœt pouĆŸit k simulaci pro sběr dat a kontrolnĂ­ systĂ©my pro vodnĂ­ elektrĂĄrny v prostƙedĂ­ Matlab / Simulink a TrueTime Simulink knihovnu. UvaĆŸovanĂĄ elektrĂĄrna sestĂĄvĂĄ z vodnĂ­ turbĂ­ny pƙipojenĂ© k synchronnĂ­mu generĂĄtoru s budicĂ­ soustavou, generĂĄtor je pƙipojen k veƙejnĂ© elektrickĂ© sĂ­ti. SimulacĂ­ vodnĂ­ turbĂ­ny a synchronnĂ­ho generĂĄtoru lze provĂ©st pomocĂ­ rĆŻznĂœch simulačnĂ­ch nĂĄstrojĆŻ. V tĂ©to prĂĄci je upƙednostƈovĂĄn SIMULINK / MATLAB pƙed jinĂœmi nĂĄstroji k modelovĂĄnĂ­ dynamik vodnĂ­ turbĂ­ny a synchronnĂ­ho stroje. Program s prostƙedĂ­m MATLAB SIMULINK vyuĆŸĂ­vĂĄ k ƙeĆĄenĂ­ schematickĂœ model vodnĂ­ elektrĂĄrny sestavenĂœ ze zĂĄkladnĂ­ch funkčnĂ­ch blokĆŻ. Tento pƙístup je pedagogicky lepĆĄĂ­ neĆŸ komplikovanĂ© kĂłdy jinĂœch softwarovĂœch programĆŻ. Knihovna programu Simulink obsahuje funkčnĂ­ bloky, kterĂ© mohou bĂœt spojovĂĄny, upravovĂĄny a modelovĂĄny. K vytvoƙenĂ­ a simulovĂĄnĂ­ internetovĂœch a Real Time systĂ©mĆŻ je moĆŸnĂ© pouĆŸĂ­t bud‘ knihovnu simulinku Real-Time nebo TRUETIME, v prĂĄci byla pouĆŸita knihovna TRUETIME.Hydropower has now become the best source of electricity on earth. It is produced due to the energy provided by moving or falling water. History proves that the cost of this electricity remains constant over the year. Because of the many advantages, most of the countries now have hydropower as the source of major electricity producer. The most important advantage of hydropower is that it is green energy, which mean that no air or water pollutants are produced, also no greenhouse gases like carbon dioxide are produced which makes this source of energy environment-friendly. It prevents us from the danger of global warming. Using internet techniques to control several hydroelectric plants has very important advantages, as reducing operating costs and the flexibility of meeting changes of energy demand occurred in consumption side. Also it is very effective to confront large disturbances of electrical grid, such as adding or removing large loads, and faults. In the other hand, data acquisition systems provides very useful information for both typical and scientific analysis, such as economical costs reducing, fault prediction systems, demand prediction, maintenance schedules, decision support systems and many other benefits. This thesis describes a generalized model which can be used to simulate a data acquisition and control system of hydroelectric power plant using MATLAB/SIMULINK and TrueTime simulink library. The plant considered consists of hydro turbine connected to synchronous generator with excitation system, and the generator is connected to public grid. Simulation of hydro turbine and synchronous generator can be done using various simulation tools, In this work, SIMULINK/MATLAB is favored over other tools in modeling the dynamics of a hydro turbine and synchronous machine. The SIMULINK program in MATLAB is used to obtain a schematic model of the hydro plant by means of basic function blocks. This approach is pedagogically better than using a compilation of program code as in other software programs .The library of SIMULINK software programs includes function blocks which can be linked and edited to model. Either Simulink Real-Time library or TrueTime library can be used to build and simulate internet and real time systems, in this thesis the TrueTime library was used.

    Real-time characteristics of switched ethernet for "1553B" -embedded applications : simulation and analysis

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    In our previous work , Full Duplex Switched Ethernet was put forward as an attractive candidate to replace the MIL-STD 1553B data bus, in next generation "1553B"-embedded applications. An analytic study was conducted, using the Network Calculus formalism, to evaluate the deterministic guarantees offered by our proposal. Obtained results showed the effectiveness of traffic shaping techniques, combined with priority handling mechanisms on Full Duplex Switched Ethernet in order to satisfy 1553B-like real-time constraints. In this paper, we extend this work by the use of simulation. This gives the possibility to capture additional characteristics of the proposed architecture with respect to the analytical study, which was basically used to evaluate worst cases and deterministic guarantees. Hence, to assess the real-time characteristics of our proposed interconnection technology, the results yielded by simulation are discussed and average latencies distributions are considered

    The CMS Event Builder

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    The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.Comment: Conference CHEP0

    Integrated Transversal Equalizers in High-Speed Fiber-Optic Systems

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    Intersymbol interference (ISI) caused by intermodal dispersion in multimode fibers is the major limiting factor in the achievable data rate or transmission distance in high-speed multimode fiber-optic links for local area networks applications. Compared with optical-domain and other electrical-domain dispersion compensation methods, equalization with transversal filters based on distributed circuit techniques presents a cost-effective and low-power solution. The design of integrated distributed transversal equalizers is described in detail with focus on delay lines and gain stages. This seven-tap distributed transversal equalizer prototype has been implemented in a commercial 0.18-”m SiGe BiCMOS process for 10-Gb/s multimode fiber-optic links. A seven-tap distributed transversal equalizer reduces the ISI of a 10-Gb/s signal after 800 m of 50-”m multimode fiber from 5 to 1.38 dB, and improves the bit-error rate from about 10^-5 to less than 10^-12

    Performance study of voice over frame relay : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Information Engineering, Massey University, Albany, New Zealand

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    Frame Relay (FR) represents an important paradigm shift in modern telecommunication. This technology is beginning to evolve from data only application to broad spectrum of multimedia users and potential to provide end users with cost effective transport of voice traffic for intra office communication. In this project the recent development in voice communication over Frame relay is investigated. Simulations were carried out using OPNET, a powerful simulation software. Following the simulation model, a practical design of the LAN-to-LAN connectivity experiment was also done in the Net Lab. From the results of the simulation, Performance measures such as delay, jitter, and throughput are reported. It is evident from the results that real-time voice or video across a frame relay network can provide acceptable performance

    The Dynamics of Internet Traffic: Self-Similarity, Self-Organization, and Complex Phenomena

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    The Internet is the most complex system ever created in human history. Therefore, its dynamics and traffic unsurprisingly take on a rich variety of complex dynamics, self-organization, and other phenomena that have been researched for years. This paper is a review of the complex dynamics of Internet traffic. Departing from normal treatises, we will take a view from both the network engineering and physics perspectives showing the strengths and weaknesses as well as insights of both. In addition, many less covered phenomena such as traffic oscillations, large-scale effects of worm traffic, and comparisons of the Internet and biological models will be covered.Comment: 63 pages, 7 figures, 7 tables, submitted to Advances in Complex System

    Technical Proposal for FASER: ForwArd Search ExpeRiment at the LHC

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    FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment.Comment: 82 pages, 62 figures; submitted to the CERN LHCC on 7 November 201
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