2,280 research outputs found
Reducing Congestion Effects by Multipath Routing in Wireless Networks
We propose a solution to improve fairness and increasethroughput in wireless networks with location information.Our approach consists of a multipath routing protocol, BiasedGeographical Routing (BGR), and two congestion controlalgorithms, In-Network Packet Scatter (IPS) and End-to-EndPacket Scatter (EPS), which leverage BGR to avoid the congestedareas of the network. BGR achieves good performancewhile incurring a communication overhead of just 1 byte perdata packet, and has a computational complexity similar togreedy geographic routing. IPS alleviates transient congestion bysplitting traffic immediately before the congested areas. In contrast,EPS alleviates long term congestion by splitting the flow atthe source, and performing rate control. EPS selects the pathsdynamically, and uses a less aggressive congestion controlmechanism on non-greedy paths to improve energy efficiency.Simulation and experimental results show that our solutionachieves its objectives. Extensive ns-2 simulations show that oursolution improves both fairness and throughput as compared tosingle path greedy routing. Our solution reduces the variance ofthroughput across all flows by 35%, reduction which is mainlyachieved by increasing throughput of long-range flows witharound 70%. Furthermore, overall network throughput increasesby approximately 10%. Experimental results on a 50-node testbed are consistent with our simulation results, suggestingthat BGR is effective in practice
Rolling Tachyon in Nonlocal Cosmology
Nonlocal cosmological models derived from String Field Theory are considered.
A new method for constructing rolling tachyon solutions in the FRW metric in
two field configuration is proposed and solutions of the Friedman equations
with nonlocal operator are presented. The cosmological properties of these
solutions are discussed.Comment: 4 pages, 2 figures. Contribution to the proceedings of PASCOS-07, 2-7
July 2007, Imperial College, Londo
STUDIES ON THE MAIN CHEMICAL COMPOUNDS AND QUALITY INDICES OF RED WINES FROM THE MAIN VINEYARDS IN OLTENIA
Recently, worldwide, there has been a decrease in wine consumption, as the consumer has become much more attentive to the quality of this food, refusing products that do not meet certain standards. At the same time, the new world wine regions specialize in quality production, coming on the market with a varied offer and at a convenient price. The fame of the particularly pleasant characteristics of Romanian wines is given not only by the extremely high value of several local varieties, which have given fame to some wine centers: Fetească alba by Alba Iulia, Grasa by Cotnari, Tămâioasă by Drăgăşani, or by Pietroasele, Busuioacă by Bohotin, Fetească neagră de Nicoreşti, Negru de Dragasani, etc., but also the fact that the most famous foreign varieties, which made famous certain regions and countries (Traminer, Sauvignon, Cabernet Sauvignon, Merlot, Pinot), cultivated in Romania wines that have often equaled or surpassed, by their "generosity" and finesse, those of the countries of origin. For wine and especially red wine, it is important to establish its typicality and authenticity due to its impact on the large mass of knowledgeable consumers who value quality and safety.
Results from the NEMO 3 experiment
The aim of the NEMO 3 experiment is the search for neutrinoless double beta
decay and precise measurement of two-neutrino double beta decay of several
isotopes. The experiment has been taking data since 2003. Since no evidence for
neutrinoless double beta decay of Mo100 and Se82 has been found, a 90% C.L.
lower limit on the half-life of this process and corresponding upper limit on
the effective Majorana neutrino mass are derived. The data are also interpreted
in terms of alternative models, such as weak right-handed currents or Majoron
emission. In addition, NEMO 3 has performed precision measurements of the
two-neutrino double beta decay for seven different isotopes. The most recent
experimental results of NEMO 3 are presented in this paper.Comment: 5 pages, 2 tables, talk at the 10th ICATPP Conference (Como, Italy, 8
- 12 October 2007
Robust adaptive beamforming for MIMO monopulse radar
Researchers have recently proposed a widely separated multiple-input multiple-output (MIMO) radar using monopulse angle estimation techniques for target tracking. The widely separated antennas provide improved tracking performance by mitigating complex target radar cross-section fades and angle scintillation. An adaptive array is necessary in this paradigm because the direct path from any transmitter could act as a jammer at a receiver. When the target-free covariance matrix is not available, it is critical to include robustness into the adaptive beamformer weights. This work explores methods of robust adaptive monopulse beamforming techniques for MIMO tracking radar
Lambda hyperonic effect on the normal driplines
A generalized mass formula is used to calculate the neutron and proton drip
lines of normal and lambda hypernuclei treating non-strange and strange nuclei
on the same footing. Calculations suggest existence of several bound
hypernuclei whose normal cores are unbound. Addition of Lambda or,
Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the
neutron and proton driplines from their conventional limits.Comment: 6 pages, 4 tables, 0 figur
An integrative approach based on probabilistic modelling and statistical inference for morpho-statistical characterization of astronomical data
This paper describes several applications in astronomy and cosmology that are
addressed using probabilistic modelling and statistical inference
Lp solutions of backward stochastic differential equations
AbstractIn this paper, we are interested in solving backward stochastic differential equations (BSDEs for short) under weak assumptions on the data. The first part of the paper is devoted to the development of some new technical aspects of stochastic calculus related to BSDEs. Then we derive a priori estimates and prove existence and uniqueness of solutions in Lp p>1, extending the results of El Karoui et al. (Math. Finance 7(1) (1997) 1) to the case where the monotonicity conditions of Pardoux (Nonlinear Analysis; Differential Equations and Control (Montreal, QC, 1998), Kluwer Academic Publishers, Dordrecht, pp. 503–549) are satisfied. We consider both a fixed and a random time interval. In the last section, we obtain, under an additional assumption, an existence and uniqueness result for BSDEs on a fixed time interval, when the data are only in L1
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