822 research outputs found
Auction-Based Distributed Resource Allocation for Cooperation Transmission in Wireless Networks
Cooperative transmission can greatly improve communication system performance
by taking advantage of the broadcast nature of wireless channels. Most previous
work on resource allocation for cooperation transmission is based on
centralized control. In this paper, we propose two share auction mechanisms,
the SNR auction and the power auction, to distributively coordinate the
resource allocation among users. We prove the existence, uniqueness and
effectiveness of the auction results. In particular, the SNR auction leads to a
fair resource allocation among users, and the power auction achieves a solution
that is close to the efficient allocation.Comment: To appear in the Proceedings of the IEEE IEEE Global Communications
Conference (GLOBECOM), Washington, DC, November 26 - 30, 200
Auction-based Resource Allocation for Multi-relay Asynchronous Cooperative Networks
Resource allocation is considered for cooperative transmissions in
multiple-relay wireless networks. Two auction mechanisms, SNR auctions and
power auctions, are proposed to distributively coordinate the allocation of
power among multiple relays. In the SNR auction, a user chooses the relay with
the lowest weighted price. In the power auction, a user may choose to use
multiple relays simultaneously, depending on the network topology and the
relays' prices. Sufficient conditions for the existence (in both auctions) and
uniqueness (in the SNR auction) of the Nash equilibrium are given. The fairness
of the SNR auction and efficiency of the power auction are further discussed.
It is also proven that users can achieve the unique Nash equilibrium
distributively via best response updates in a completely asynchronous manner.Comment: To appear in the Proceedings of the 2008 IEEE International
Conference on Acoustics, Speech and Signal Processing, Las Vegas, NV, March
30 to April 4, 200
Stochastic volatility with an Ornstein-Uhlenbeck process: An extension
In this paper, we reexamine and extend the stochastic volatility model of Stein and Stein (1991) where volatility follows a mean-reversion Ornstein-Uhlenbeck process. Using Fourier inversion techniques we are able to allow for correlation between instan-taneous volatilities and the underlying stock returns. A closed-form pricing Solution for European options is derived and some numerical examples are given
Blow-up for the compressible isentropic Navier-Stokes-Poisson equations
summary:We will show the blow-up of smooth solutions to the Cauchy problems for compressible unipolar isentropic Navier-Stokes-Poisson equations with attractive forcing and compressible bipolar isentropic Navier-Stokes-Poisson equations in arbitrary dimensions under some restrictions on the initial data. The key of the proof is finding the relations between the physical quantities and establishing some differential inequalities
Metal adsorption by quasi cellulose xanthogenates derived from aquatic and terrestrial plant materials
The FTIR spectra, SEM-EDXA and copper adsorption capacities of the raw plant materials, alkali treated straws and cellulose xanthogenate derivatives of Eichhornia crassipes shoot, rape straw and corn stalk were investigated. FTIR spectra indicated that of the three plant materials, the aquatic biomass of Eichhornia crassipes shoot contained more O-H and C=O groups which accounted for the higher Cu²⁺ adsorption capacities of the raw and alkali treated plant material. SEM-EDXA indicated the incorporation of sulphur and magnesium in the cellulose xanthogenate. The Cu²⁺ adsorption capacities of the xanthogenates increased with their magnesium and sulphur contents. However more copper was adsorbed than that can be explained by exchange of copper with magnesium. Precipitation may contribute to the enhanced uptake of copper by the cellulose xanthogenate
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