Search results for "Area network"
showing 10 items of 74 documents
Efficiency analysis of burst transmissions with block ACK in contention-based 802.11e WLANs
2005
The channel utilization efficiency of the standard 802.11 networks is severely compromised when high data transmission rates are employed, since physical layer headers and control frames are transmitted at low rate, thus wasting more channel time, proportionally. The extensions defined in the emerging 802.11e for quality-of-service (QoS) provisioning include some new mechanisms developed in order to improve the efficiency. Those include data transmission bursting (referred to as TXOP operation) and acknowledgment aggregation (referred to as block ACK). These two features allow it to offer new data transmission services, in which the data delivery and acknowledgment unit is not a single fram…
Virtual Environment for Implementation and Testing Private Wide Area Network Solutions
2013
In this paper the concept of virtual environment for implementation and testing private Wide Area Network (WAN) solutions is presented. The VMware vSphere virtualization platform is used. The paper presents the ability to reflect the structure of any given WAN topology using Vyatta software routers and VMware virtualization platform and verifies its reliability regarding data transfer. The paper includes a number of performance tests to verify the dependability of the proposed solution and provide a proof-of-concept for the network topology during the Design phase of the PPDIOO methodology, right before the Implementation phase.
The Two-Criteria Topological Design Problem in WAN with Delay Constraint: An Algorithm and Computational Results
2003
The problem is concerned with designing of wide area networks (WAN). The problem consists in selection of flow routes, channel capacities and wide area network topology in order to minimize the total average delay per packet and the leasing cost of channels subject to delay constraint. The problem is NP complete. Then, the branch and bound method is used to construct the exact algorithm. Lower bound of the criterion function is proposed. Computational results are reported. Based on computational experiments, several properties of the considered problem are formulated.
Unified computing facility design based on open source software
2012
The article describes e-infrastructure development in Latvia and migration to national Cloud as regional partner facility (RPF) in European Union (EU). In Latvia many public and private Computing Clouds is in operation and problem is how to integrate these resources as one RPF and how to design one unified computing facility that is used for many different applications. The authors offer their solution at Cloud software as a Service and Hardware as a Service level which is based on usage of open source packaged bundles.
Optimal Operating Point Calculation for Medium Voltage Distribution Systems
2007
The paper deals with the calculation of the optimal working point of a distribution system, equipped with several distributed generators, able to operate also autonomously, i.e. disconnected from the main grid. When connected to the main grid, it appears in general convenient to assign the slack bus role to the bus that represents such a connection. The problem becomes more complex when maximum power transfer constraints through the connection must be taken into account. The adequate slack bus treatment is even more important when the optimal operating condition must refer to the condition subsequent to an intentional or unintentional disconnection from the main grid. The paper presents an …
A software tool to acquire, synchronise and playback multimedia data: an application in kinesiology
2000
Assessing the physical condition of the human body frequently requires evaluating different tests performed by different devices. This information has to be analysed simultaneously to derive conclusions, and so a temporal relationship must be established between the data sources. In this paper, synchronisation of the sources of information is achieved by synchronising the clocks of computers connected in a Local Area Network. A clock synchronisation protocol is used and a global time is stamped in each information data flow. During analysis, the time-stamp is used to playback the data in a synchronised way. The proposed system is valid for any medical application in which data synchronisati…
Remote programming of network robots within the UJI Industrial Robotics Telelaboratory: FPGA vision and SNRP network protocol
2009
This paper presents the UJI Industrial Robotics Telelaboratory, which lets Ph.D. and Master’s degree students perform robotics and computer vision tele-experiments. By using this system, students are able to program experiments remotely via the Web, in order to combine the use of a field-programmable gate array (FPGA) to provide real-time vision processing, a conveyor belt, and a Motoman industrial manipulator. This paper introduces the novel SNRP protocol (i.e., Simple Network Robot Protocol), which permits the integration of network robots and sensors within an e-learning platform in a simple and reliable manner. As long as the students are able to interact remotely with a real robotic sc…
Multiservice Optical Fibre Local Area Networks For Data Transmission And Telemetry In The Electric Power Industry
1986
The paper contains a review of a few of experimental optical fibre multiservice and multibranch local area networks /LANs/. Systems accomplish transmission, distribution and processing of analog or digital signals from numerous sources or measurement terminals. The authors put stress also on the possibility of combining transmission properties of fiber optic networks with fibre optic sensors. Several construction problems and chosen properties of multiport /multiterminal/ optical buses /networks/ have been considered. All examination systems of optical fibre LANs are discussed in respect of application them as telemetric, transmission, telesignaling and telecontrol systems for the power ele…
On-body to on-body channel characterization
2011
Interest in on-body communication channels is growing as the use of wireless devices increases in medical, consumer and military sensor applications. This paper presents an experimental investigation and analysis of the narrowband on-body propagation channel. This analysis considers each of the factors affecting the channel during a range of stationary and motion activities in different environments with actual wireless mote devices on the body. Use of such motes allows greater freedom in the subject's movements and the inclusion of real-world indoor and outdoor environments in a test sequence. This paper identifies and analyses the effect of the different components of the signal propagati…
Integration and application of emerging RF systems formed by wireless sensor networks: exhaustive experiment to their implantation in different envir…
2007
This paper shows the possibility to use Bluetooth for wireless short range communication in an industrial environment. Traditionally many types of devices have been delivered as mechanical devices and more or less all or the intelligence and control has been added. Nowadays there is a growing trend towards a higher level of built-in intelligence in the devices, constituting the intelligent nodes. This type of systems allows the implementation of highly flexible control systems capable of adapting themselves to different situations. With the introduction of RF systems, another dimension is aggregated, the possibility to wirelessly connect to the devices. The technology makes it possible to e…