5,536 research outputs found
Ethernet - a survey on its fields of application
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 fieldâs 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
Performance analysis of a Master/Slave switched Ethernet for military embedded applications
Current military communication network is a generation
old and is no longer effective in meeting the emerging
requirements imposed by the next generation military embedded applications. A new communication network based upon Full Duplex Switched Ethernet is proposed in this paper to overcome these limitations. To allow existing military subsystems to be easily supported by a Switched Ethernet network, our proposal consists in keeping their current centralized communication scheme by using an optimized master/slave transmission control on Switched Ethernet thanks to the Flexible Time Triggered (FTT) paradigm. Our main objective is to assess the performance
of such a proposal and estimate the quality of service we
can expect in terms of latency. Using the Network Calculus formalism, schedulability analysis are determined. These analysis are illustrated in the case of a realistic military embedded application extracted from a real military aircraft network, to highlight the proposal's ability to support the required time constrained communications
Centralized vs distributed communication scheme on switched ethernet for embedded military applications
Current military communication network is a generation
old and is no longer effective in meeting the emerging
requirements imposed by the future embedded military applications. Therefore, a new interconnection system is needed to overcome these limitations. Two new communication networks based upon Full Duplex Switched Ethernet are presented herein in this aim. The first one uses a distributed communication scheme where equipments can emit their data simultaneously, which clearly improves systemâs throughput and flexibility. However, migrating all existing applications into a compliant form could be an expensive step. To avoid this process, the second proposal consists in keeping the current centralized communication scheme. Our objective is to assess and compare the real time
guarantees that each proposal can offer. The paper includes the functional description of each proposed communication network and a military avionic application to highlight proposals ability to support the required time constrained communications
Evaluation of Time-Critical Communications for IEC 61850-Substation Network Architecture
Present-day developments, in electrical power transmission and distribution,
require considerations of the status quo. In other meaning, international
regulations enforce increasing of reliability and reducing of environment
impact, correspondingly they motivate developing of dependable systems. Power
grids especially intelligent (smart grids) ones become industrial solutions
that follow standardized development. The International standardization, in the
field of power transmission and distribution, improve technology influences.
The rise of dedicated standards for SAS (Substation Automation Systems)
communications, such as the leading International Electro-technical Commission
standard IEC 61850, enforces modern technological trends in this field. Within
this standard, a constraint of low ETE (End-to-End) latency should be
respected, and time-critical status transmission must be achieved. This
experimental study emphasis on IEC 61850 SAS communication standard, e.g. IEC
61850 GOOSE (Generic Object Oriented Substation Events), to implement an
investigational method to determine the protection communication delay. This
method observes GOOSE behaviour by adopting monitoring and analysis
capabilities. It is observed by using network test equipment, i.e. SPAN (Switch
Port Analyser) and TAP (Test Access Point) devices, with on-the-shelf available
hardware and software solutions
Exploring Alternatives to use Master/Slave Full Duplex Switched Ethernet for Avionics Embedded Applications
The complexity of distributed real-time systems, including military embedded applications, is increasing due to an increasing number of nodes, their functionality and higher amounts of exchanged data. This higher complexity imposes major development challenges when nonfunctional properties must be enforced. On the other hand, the current military communication networks are a generation old and are no longer effective in facing such increasingly complex requirements. A new communication network, based on Full Duplex Switched Ethernet and Master/slave approach, has been proposed previously. However, this initial approach is not efficient in terms of network bandwidth utilization. In this paper we propose two new alternative approaches that can use the network bandwidth more efficiently. In addition we provide a preliminary qualitative assessment of the three approaches concerning different factors such as performance, scalability, complexity and flexibility
Data Acquisition and Control System of Hydroelectric Power Plant Using Internet Techniques
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 prĆŻbÄhu celĂ©ho roku. Vzhledem k mnoha vĂœhodĂĄm, vÄtĆĄina zemĂ nynĂ vyuĆŸĂvĂĄ vodnĂ energie jako hlavnĂ zdroj pro vĂœrobu elektrickĂ© energie.NejdĆŻleĆŸitÄjĆĄĂ vĂœhodou je, ĆŸe vodnĂ energie je zelenĂĄ energie, coĆŸ znamenĂĄ, ĆŸe ĆŸĂĄdnĂ© vzduĆĄnĂ© nebo vodnĂ zneÄiĆĄĆ„ujĂcĂ lĂĄtky nejsou vyrĂĄbÄny, takĂ© ĆŸĂĄdnĂ© sklenĂkovĂ© plyny jako oxid uhliÄitĂœ nejsou vyrĂĄbÄny, coĆŸ ÄinĂ tento zdroj energie ĆĄetrnĂœ k ĆŸivotnĂmu prostĆedĂ. A tak brĂĄnĂ nebezpeÄĂ globĂĄlnĂho oteplovĂĄnĂ. PouĆŸitĂ internetovĂ© techniky k ovladĂĄnĂ nÄkolika vodnĂch elektrĂĄren mĂĄ velmi vĂœznamnĂ© vĂœhody, jako snĂĆŸenĂ provoznĂch nĂĄkladĆŻ a flexibilitu uspokojenĂ zmÄny poptĂĄvky po energii na stranÄ spotĆeby. TakĂ© velmi efektivnÄ ÄelĂ velkĂœm naruĆĄenĂm elektrickĂ© sĂtÄ, jako je napĆĂklad pĆidĂĄnĂ nebo odebrĂĄnĂ velkĂ© zĂĄtÄĆŸe, a poruch. Na druhou stranu, systĂ©m zĂskĂĄvĂĄnĂ dat poskytuje velmi uĆŸiteÄnĂ© informace pro typickĂ© i vÄdeckĂ© 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 sbÄr dat a kontrolnĂ systĂ©my pro vodnĂ elektrĂĄrny v prostĆedĂ Matlab / Simulink a TrueTime Simulink knihovnu. UvaĆŸovanĂĄ elektrĂĄrna sestĂĄvĂĄ z vodnĂ turbĂny pĆipojenĂ© k synchronnĂmu generĂĄtoru s budicĂ soustavou, generĂĄtor je pĆipojen k veĆejnĂ© elektrickĂ© sĂti. SimulacĂ vodnĂ turbĂny a synchronnĂho generĂĄtoru lze provĂ©st pomocĂ rĆŻznĂœch simulaÄnĂch nĂĄstrojĆŻ. V tĂ©to prĂĄci je upĆednostĆovĂĄn SIMULINK / MATLAB pĆed jinĂœmi nĂĄstroji k modelovĂĄnĂ dynamik vodnĂ turbĂny a synchronnĂho stroje. Program s prostĆedĂm MATLAB SIMULINK vyuĆŸĂvĂĄ k ĆeĆĄenĂ schematickĂœ model vodnĂ elektrĂĄrny sestavenĂœ ze zĂĄkladnĂch funkÄnĂch blokĆŻ. Tento pĆĂstup je pedagogicky lepĆĄĂ neĆŸ komplikovanĂ© kĂłdy jinĂœch softwarovĂœch programĆŻ. Knihovna programu Simulink obsahuje funkÄnĂ bloky, kterĂ© mohou bĂœt spojovĂĄny, upravovĂĄny a modelovĂĄny. K vytvoĆenĂ a simulovĂĄnĂ internetovĂœch a Real Time systĂ©mĆŻ je moĆŸnĂ© pouĆŸĂt budâ 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.
Simulation and experimental evaluation of a flexible time triggered ethernet architecture applied in satellite nano/micro launchers
The success of small satellites has led to the study of new technologies for the realization of Nano and Micro Launch Vehicle (NMLV) in order to make competitive launch costs. The paper has the objective to define and experimentally investigate the performance of a communication system for NMLV interconnecting the End Systems as On-Board Computer (OBC), telemetry apparatus, Navigation Unit...we propose a low cost Ethernet-based solution able to provide the devices with high interconnection bandwidth. To guarantee hard delays to the Guide, Navigation and Control applications we propose some architectural changes of the traditional Ethernet network with the introduction of a layer implemented in the End Systems and allow for the lack of any contention on the network links. We show how the proposed solution has comparable performance to the one of TTEthernet standard that is a very expensive solution. An experimental test-bed equipped with Ethernet switches and Hercules boards by Texas Instruments is also provided to prove the feasibility of the proposed solution
Load flow studies on stand alone microgrid system in Ranau, Sabah
This paper presents the power flow or load flow analysis of Ranau microgrid, a
standalone microgrid in the district of Ranau,West Coast Division of Sabah. Power
flow for IEEE 9 bus also performed and analyzed. Power flow is define as an
important tool involving numerical analysis applied to power system. Power flow
uses simplified notation such as one line diagram and per-unit system focusing on
voltages, voltage angles, real power and reactive power. To achieved that purpose,
this research is done by analyzing the power flow analysis and calculation of all the
elements in the microgrid such as generators, buses, loads, transformers,
transmission lines using the Power Factory DIGSilent 14 software to calculate the
power flow. After the analysis and calculations, the results were analysed and
compared
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