669 research outputs found
Estimation, Analysis and Smoothing of Self-Similar Network Induced Delays in Feedback Control of Nuclear Reactors
This paper analyzes a nuclear reactor power signal that suffers from network
induced random delays in the shared data network while being fed-back to the
Reactor Regulating System (RRS). A detailed study is carried out to investigate
the self similarity of random delay dynamics due to the network traffic in
shared medium. The fractionality or selfsimilarity in the network induced delay
that corrupts the measured power signal coming from Self Powered Neutron
Detectors (SPND) is estimated and analyzed. As any fractional order randomness
is intrinsically different from conventional Gaussian kind of randomness, these
delay dynamics need to be handled efficiently, before reaching the controller
within the RRS. An attempt has been made to minimize the effect of the
randomness in the reactor power transient data with few classes of smoothing
filters. The performance measure of the smoothers with fractional order noise
consideration is also investigated into.Comment: 6 pages, 6 figure
Proposed Fuzzy Real-Time HaPticS Protocol Carrying Haptic Data and Multisensory Streams
Sensory and haptic data transfers to critical real-time applications over the Internet require better than best effort transport, strict timely and reliable ordered deliveries. Multi-sensory applications usually include video and audio streams with real-time control and sensory data, which aggravate and compress within real-time flows. Such real-time are vulnerable to synchronization to synchronization problems, if combined with poor Internet links. Apart from the use of differentiated QoS and MPLS services, several haptic transport protocols have been proposed to confront such issues, focusing on minimizing flows rate disruption while maintaining a steady transmission rate at the sender. Nevertheless, these protocols fail to cope with network variations and queuing delays posed by the Internet routers.
This paper proposes a new haptic protocol that tries to alleviate such inadequacies using three different metrics: mean frame delay, jitter and frame loss calculated at the receiver end and propagated to the sender. In order to dynamically adjust flow rate in a fuzzy controlled manners, the proposed protocol includes a fuzzy controller to its protocol structure. The proposed FRTPS protocol (Fuzzy Real-Time haPticS protocol), utilizes crisp inputs into a fuzzification process followed by fuzzy control rules in order to calculate a crisp level output service class, denoted as Service Rate Level (SRL). The experimental results of FRTPS over RTP show that FRTPS outperforms RTP in cases of congestion incidents, out of order deliveries and goodput
Roaming Real-Time Applications - Mobility Services in IPv6 Networks
Emerging mobility standards within the next generation Internet Protocol,
IPv6, promise to continuously operate devices roaming between IP networks.
Associated with the paradigm of ubiquitous computing and communication, network
technology is on the spot to deliver voice and videoconferencing as a standard
internet solution. However, current roaming procedures are too slow, to remain
seamless for real-time applications. Multicast mobility still waits for a
convincing design. This paper investigates the temporal behaviour of mobile
IPv6 with dedicated focus on topological impacts. Extending the hierarchical
mobile IPv6 approach we suggest protocol improvements for a continuous
handover, which may serve bidirectional multicast communication, as well. Along
this line a multicast mobility concept is introduced as a service for clients
and sources, as they are of dedicated importance in multipoint conferencing
applications. The mechanisms introduced do not rely on assumptions of any
specific multicast routing protocol in use.Comment: 15 pages, 5 figure
Analysis domain model for shared virtual environments
The field of shared virtual environments, which also
encompasses online games and social 3D environments, has a
system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model
FPGA-Based Testbed for Synchronization on Ethernet Fronthaul with Phase Noise Measurements
Cloud radio access network (C-RAN) is a recent trend of RAN architecture positioned to help the operators to address challenges of new wireless services, such as emerging 4G and 5G mobile networks. C-RAN uses baseband processing units in a central server which connects to the radio front-ends at cell sites via the so-called fronthaul network. The fronthaul infrastructure is currently provided by CPRI (Common Public
Radio Interface) and OBSAI (Open Basestation Architecture Initiative) industry standards which use dedicated optical links with high deployment costs. An alternative is to use Ethernet technology aiming to reuse of network infrastructure available in many commercial buildings. However, in contrast to the
traditional synchronous fronthaul, Ethernet suffers with packet delay variation (PDV) and challenging synchronization recovery.
This work presents a complete and flexible testbed to evaluate Ethernet-based fronthaul. The system is validated via extensive measurements that show the effects of synchronization procedures and network impairments on regenerated clock phase noise
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