11,678 research outputs found
Stochastic user behaviour modelling and network simulation for resource management in cooperation with mobile telecommunications and broadcast networks
The latest generations of telecommunications networks have been designed to deliver higher data rates than widely used second generation telecommunications networks, providing flexible communication capabilities that can deliver high quality video images. However, these new generations of telecommunications networks are interference limited, impairing their performance in cases of heavy traffic and high usage. This limits the services offered by a telecommunications network operator to those that the operator is confident their network can meet the demand for. One way to lift this constraint would be for the mobile telecommunications network operator to obtain the cooperation of a broadcast network operator so that during periods when the demand for the service is too high for the telecommunications network to meet, the service can be transferred to the broadcast network. In the United Kingdom the most recent telecommunications networks on the market are third generation UMTS networks while the terrestrial digital broadcast networks are DVB-T networks. This paper proposes a way for UMTS network operators to forecast the traffic associated with high demand services intended to be deployed on the UMTS network and when demand requires to transfer it to a cooperating DVB-T network. The paper aims to justify to UMTS network operators the use of a DVB-T network as a support for a UMTS network by clearly showing how using a DVB-T network to support it can increase the revenue generated by their network
Report : review of the literature : maintenance and rehabilitation costs for roads (Risk-based Analysis)
Realistic estimates of short- and long-term (strategic) budgets for maintenance and
rehabilitation of road assessment management should consider the stochastic
characteristics of asset conditions of the road networks so that the overall variability
of road asset data conditions is taken into account.
The probability theory has been used for assessing life-cycle costs for bridge
infrastructures by Kong and Frangopol (2003), Zayed et.al. (2002), Kong and
Frangopol (2003), Liu and Frangopol (2004), Noortwijk and Frangopol (2004), Novick
(1993). Salem 2003 cited the importance of the collection and analysis of existing
data on total costs for all life-cycle phases of existing infrastructure, including bridges,
road etc., and the use of realistic methods for calculating the probable useful life of
these infrastructures (Salem et. al. 2003). Zayed et. al. (2002) reported conflicting
results in life-cycle cost analysis using deterministic and stochastic methods.
Frangopol et. al. 2001 suggested that additional research was required to develop
better life-cycle models and tools to quantify risks, and benefits associated with
infrastructures.
It is evident from the review of the literature that there is very limited information on
the methodology that uses the stochastic characteristics of asset condition data for
assessing budgets/costs for road maintenance and rehabilitation (Abaza 2002,
Salem et. al. 2003, Zhao, et. al. 2004). Due to this limited information in the research
literature, this report will describe and summarise the methodologies presented by
each publication and also suggest a methodology for the current research project
funded under the Cooperative Research Centre for Construction Innovation CRC CI
project no 2003-029-C
Unsplittable Load Balancing in a Network of Charging Stations Under QoS Guarantees
The operation of the power grid is becoming more stressed, due to the
addition of new large loads represented by Electric Vehicles (EVs) and a more
intermittent supply due to the incorporation of renewable sources. As a
consequence, the coordination and control of projected EV demand in a network
of fast charging stations becomes a critical and challenging problem.
In this paper, we introduce a game theoretic based decentralized control
mechanism to alleviate negative impacts from the EV demand. The proposed
mechanism takes into consideration the non-uniform spatial distribution of EVs
that induces uneven power demand at each charging facility, and aims to: (i)
avoid straining grid resources by offering price incentives so that customers
accept being routed to less busy stations, (ii) maximize total revenue by
serving more customers with the same amount of grid resources, and (iii)
provide charging service to customers with a certain level of
Quality-of-Service (QoS), the latter defined as the long term customer blocking
probability. We examine three scenarios of increased complexity that gradually
approximate real world settings. The obtained results show that the proposed
framework leads to substantial performance improvements in terms of the
aforementioned goals, when compared to current state of affairs.Comment: Accepted for Publication in IEEE Transactions on Smart Gri
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