145 research outputs found
Dravidian Narratives constructed by Mudiyarasan's Poems
The relationship between literature and movements is close. One depends on the other. Both have a system of giving and receiving. The new ones are the desired ones. Making major changes possible in society. Various movements have played a role in the creation of modern Tamil literature. Movements use works of art as a tool to bring about change in the social and political sphere. Dravidian ideologies have spread their ideologies in many spheres, such as short stories, novels, poetry, drama, and cinema. Countless people joined the movement and helped to expand the works of art. The role of the monarch in traditional poetry is important. This article describes them
Network Coding for Computing: Cut-Set Bounds
The following \textit{network computing} problem is considered. Source nodes
in a directed acyclic network generate independent messages and a single
receiver node computes a target function of the messages. The objective is
to maximize the average number of times can be computed per network usage,
i.e., the ``computing capacity''. The \textit{network coding} problem for a
single-receiver network is a special case of the network computing problem in
which all of the source messages must be reproduced at the receiver. For
network coding with a single receiver, routing is known to achieve the capacity
by achieving the network \textit{min-cut} upper bound. We extend the definition
of min-cut to the network computing problem and show that the min-cut is still
an upper bound on the maximum achievable rate and is tight for computing (using
coding) any target function in multi-edge tree networks and for computing
linear target functions in any network. We also study the bound's tightness for
different classes of target functions. In particular, we give a lower bound on
the computing capacity in terms of the Steiner tree packing number and a
different bound for symmetric functions. We also show that for certain networks
and target functions, the computing capacity can be less than an arbitrarily
small fraction of the min-cut bound.Comment: Submitted to the IEEE Transactions on Information Theory (Special
Issue on Facets of Coding Theory: from Algorithms to Networks); Revised on
Aug 9, 201
Research on efficiency and privacy issues in wireless communication
Wireless spectrum is a limited resource that must be used efficiently. It is also
a broadcast medium, hence, additional procedures are required to maintain communication
over the wireless spectrum private. In this thesis, we investigate three key
issues related to efficient use and privacy of wireless spectrum use. First, we propose
GAVEL, a truthful short-term auction mechanism that enables efficient use of the wireless
spectrum through the licensed shared access model. Second, we propose CPRecycle,
an improved Orthogonal Frequency Division Multiplexing (OFDM) receiver that
retrieves useful information from the cyclic prefix for interference mitigation thus improving
spectral efficiency. Third and finally, we propose WiFi Glass, an attack vector
on home WiFi networks to infer private information about home occupants.
First we consider, spectrum auctions. Existing short-term spectrum auctions do
not satisfy all the features required for a heterogeneous spectrum market. We discover
that this is due to the underlying auction format, the sealed bid auction. We propose
GAVEL, a truthful auction mechanism, that is based on the ascending bid auction
format, that avoids the pitfalls of existing auction mechanisms that are based on the
sealed bid auction format. Using extensive simulations we observe that GAVEL can
achieve better performance than existing mechanisms.
Second, we study the use of cyclic prefix in Orthogonal Frequency Division Multiplexing.
The cyclic prefix does contain useful information in the presence of interference.
We discover that while the signal of interest is redundant in the cyclic prefix,
the interference component varies significantly. We use this insight to design CPRecycle,
an improved OFDM receiver that is capable of using the information in the
cyclic prefix to mitigate various types of interference. It improves spectral efficiency
by decoding packets in the presence of interference. CPRecycle require changes to the
OFDM receiver and can be deployed in most networks today.
Finally, home WiFi networks are considered private when encryption is enabled
using WPA2. However, experiments conducted in real homes, show that the wireless
activity on the home network can be used to infer occupancy and activity states such as
sleeping and watching television. With this insight, we propose WiFi Glass, an attack
vector that can be used to infer occupancy and activity states (limited to three activity
classes), using only the passively sniffed WiFi signal from the home environment.
Evaluation with real data shows that in most of the cases, only about 15 minutes of
sniffed WiFi signal is required to infer private information, highlighting the need for
countermeasures
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