12,782 research outputs found
STEPS - an approach for human mobility modeling
In this paper we introduce Spatio-TEmporal Parametric Stepping (STEPS) - a simple parametric mobility model which can cover a large spectrum of human mobility patterns. STEPS makes abstraction of spatio-temporal preferences in human mobility by using a power law to rule the nodes movement. Nodes in STEPS have preferential attachment to favorite locations where they spend most of their time. Via simulations, we show that STEPS is able, not only to express the peer to peer properties such as inter-ontact/contact time and to reflect accurately realistic routing performance, but also to express the structural properties of the underlying interaction graph such as small-world phenomenon. Moreover, STEPS is easy to implement, exible to configure and also theoretically tractable
Performance evaluation of an efficient counter-based scheme for mobile ad hoc networks based on realistic mobility model
Flooding is the simplest and commonly used mechanism for broadcasting in mobile ad hoc networks (MANETs). Despite its simplicity, it can result in high redundant retransmission, contention and collision in the network, a phenomenon referred to as broadcast storm problem. Several probabilistic broadcast schemes have been proposed to mitigate this problem inherent with flooding. Recently, we have proposed a hybrid-based scheme as one of the probabilistic scheme, which combines the advantages of pure probabilistic and counter-based schemes to yield a significant performance improvement. Despite these considerable numbers of proposed broadcast schemes, majority of these schemes’ performance evaluation was based on random waypoint model. In this paper, we evaluate the performance of our broadcast scheme using a community based mobility model which is based on social network theory and compare it against widely used random waypoint mobility model. Simulation results have shown that using unrealistic movement pattern does not truly reflect on the actual performance of the scheme in terms of saved-rebroadcast, reachability and end to end delay
On the Dynamics of Human Proximity for Data Diffusion in Ad-Hoc Networks
We report on a data-driven investigation aimed at understanding the dynamics
of message spreading in a real-world dynamical network of human proximity. We
use data collected by means of a proximity-sensing network of wearable sensors
that we deployed at three different social gatherings, simultaneously involving
several hundred individuals. We simulate a message spreading process over the
recorded proximity network, focusing on both the topological and the temporal
properties. We show that by using an appropriate technique to deal with the
temporal heterogeneity of proximity events, a universal statistical pattern
emerges for the delivery times of messages, robust across all the data sets.
Our results are useful to set constraints for generic processes of data
dissemination, as well as to validate established models of human mobility and
proximity that are frequently used to simulate realistic behaviors.Comment: A. Panisson et al., On the dynamics of human proximity for data
diffusion in ad-hoc networks, Ad Hoc Netw. (2011
Probabilistic Human Mobility Model in Indoor Environment
Understanding human mobility is important for the development of intelligent
mobile service robots as it can provide prior knowledge and predictions of
human distribution for robot-assisted activities. In this paper, we propose a
probabilistic method to model human motion behaviors which is determined by
both internal and external factors in an indoor environment. While the internal
factors are represented by the individual preferences, aims and interests, the
external factors are indicated by the stimulation of the environment. We model
the randomness of human macro-level movement, e.g., the probability of visiting
a specific place and staying time, under the Bayesian framework, considering
the influence of both internal and external variables. We use two case studies
in a shopping mall and in a college student dorm building to show the
effectiveness of our proposed probabilistic human mobility model. Real
surveillance camera data are used to validate the proposed model together with
survey data in the case study of student dorm.Comment: 8 pages, 9 figures, International Joint Conference on Neural Networks
(IJCNN) 201
Spatial networks with wireless applications
Many networks have nodes located in physical space, with links more common
between closely spaced pairs of nodes. For example, the nodes could be wireless
devices and links communication channels in a wireless mesh network. We
describe recent work involving such networks, considering effects due to the
geometry (convex,non-convex, and fractal), node distribution,
distance-dependent link probability, mobility, directivity and interference.Comment: Review article- an amended version with a new title from the origina
A Conversation with Leo Goodman
Leo A. Goodman was born on August 7, 1928 in New York City. He received his
A.B. degree, summa cum laude, in 1948 from Syracuse University, majoring in
mathematics and sociology. He went on to pursue graduate studies in
mathematics, with an emphasis on mathematical statistics, in the Mathematics
Department at Princeton University, and in 1950 he was awarded the M.A. and
Ph.D. degrees. His statistics professors at Princeton were the late Sam Wilks
and John Tukey. Goodman then began his academic career as a statistician, and
also as a statistician bridging sociology and statistics, with an appointment
in 1950 as assistant professor in the Statistics Department and the Sociology
Department at the University of Chicago, where he remained, except for various
leaves, until 1987. He was promoted to associate professor in 1953, and to
professor in 1955. Goodman was at Cambridge University in 1953--1954 and
1959--1960 as visiting professor at Clare College and in the Statistical
Laboratory. And he spent 1960--1961 as a visiting professor of mathematical
statistics and sociology at Columbia University. He was also a research
associate in the University of Chicago Population Research Center from 1967 to
1987. In 1970 he was appointed the Charles L. Hutchinson Distinguished Service
Professor at the University of Chicago, a title that he held until 1987. He
spent 1984--1985 at the Center for Advanced Study in the Behavioral Sciences in
Stanford. In 1987 he was appointed the Class of 1938 Professor at the
University of California, Berkeley, in the Sociology Department and the
Statistics Department. Goodman's numerous honors include honorary D.Sc. degrees
from the University of Michigan and Syracuse University, and membership in the
National Academy of Sciences, the American Academy of Arts and Sciences, and
the American Philosophical Society.Comment: Published in at http://dx.doi.org/10.1214/08-STS276 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
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