7,206 research outputs found
Three applications for mobile epidemic algorithms
This paper presents a framework for the pervasive sharing of data using wireless networks. 'FarCry' uses the mobility of users to carry files between separated networks. Through a mix of ad-hoc and infrastructure-based wireless networking, files are transferred between users without their direct involvement. As users move to different locations, files are then transmitted on to other users, spreading and sharing information. We examine three applications of this framework. Each of these exploits the physically proximate nature of social gatherings. As people group together in, for example, business meetings and cafés, this can be taken as an indication of similar interests, e.g. in the same presentation or in a type of music. MediaNet affords sharing of media files between strangers or friends, MeetingNet shares business documents in meetings, and NewsNet shares RSS feeds between mobile users. NewsNet also develops the use of pre-emptive caching: collecting information from others not for oneself, but for the predicted later sharing with others. We offer observations on developing this system for a mobile, multi-user, multi-device environment
Studies of nucleotide sequences in TMV-RNA. II - The action of spleen diesterase
Spleen diesterase action on polynucleotide and ribonucleic acid infectivit
Picking pockets on the lawn: the development of tactics and strategies in a mobile game
This paper presents Treasure, an outdoor mobile multiplayer game inspired by Weiser’s notion of seams, gaps and breaks in different media. Playing Treasure involves movement in and out of a wi-fi network, using PDAs to pick up virtual ’coins’ that may be scattered outside network coverage. Coins have to be uploaded to a server to gain game points, and players can collaborate with teammates to double the points given for an upload. Players can also steal coins from opponents. As they move around, players’ PDAs sample network signal strength and update coverage maps. Reporting on a study of players taking part in multiple games, we discuss how their tactics and strategies developed as their experience grew with successive games. We suggest that meaningful play arises in just this way, and that repeated play is vital when evaluating such games
Hydrogeological controls on microbial activity and habitability in the Precambrian continental crust
Measurement of the ΔS=-ΔQ Amplitude from K_(e3)^0 Decay
We have measured the time distribution of the π^+e^-ν and π^-e^+ν modes from initial K^0's in a spark-chamber experiment performed at the Bevatron. From 1079 events between 0.2 and 7 K_S^0 lifetime, we find ReX=-0.069±0.036, ImX=+0.108_(-0.074)^(+0.092). This result is consistent with X=0 (relative probability = 0.25), but more than 4 standard deviations from the existing world average, +0.14 -0.13i
Irreversible Deposition of Line Segment Mixtures on a Square Lattice: Monte Carlo Study
We have studied kinetics of random sequential adsorption of mixtures on a
square lattice using Monte Carlo method. Mixtures of linear short segments and
long segments were deposited with the probability and , respectively.
For fixed lengths of each segment in the mixture, the jamming limits decrease
when increases. The jamming limits of mixtures always are greater than
those of the pure short- or long-segment deposition.
For fixed and fixed length of the short segments, the jamming limits have
a maximum when the length of the long segment increases. We conjectured a
kinetic equation for the jamming coverage based on the data fitting.Comment: 7 pages, latex, 5 postscript figure
Random sequential adsorption on a dashed line
We study analytically and numerically a model of random sequential adsorption
(RSA) of segments on a line, subject to some constraints suggested by two kinds
of physical situations:
- deposition of dimers on a lattice where the sites have a spatial extension;
- deposition of extended particles which must overlap one (or several)
adsorbing sites on the substrate.
Both systems involve discrete and continuous degrees of freedom, and, in one
dimension, are equivalent to our model, which depends on one length parameter.
When this parameter is varied, the model interpolates between a variety of
known situations : monomers on a lattice, "car-parking" problem, dimers on a
lattice. An analysis of the long-time behaviour of the coverage as a function
of the parameter exhibits an anomalous 1/t^2 approach to the jamming limit at
the transition point between the fast exponential kinetics, characteristic of
the lattice model, and the 1/t law of the continuous one.Comment: 14 pages (Latex) + 4 Postscript figure
Critical behavior of thermopower and conductivity at the metal-insulator transition in high-mobility Si-MOSFET's
This letter reports thermopower and conductivity measurements through the
metal-insulator transition for 2-dimensional electron gases in high mobility
Si-MOSFET's. At low temperatures both thermopower and conductivity show
critical behavior as a function of electron density which is very similar to
that expected for an Anderson transition. In particular, when approaching the
critical density from the metallic side the diffusion thermopower appears to
diverge and the conductivity vanishes. On the insulating side the thermopower
shows an upturn with decreasing temperature.Comment: 4 pages with 3 figure
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