Huy A. Nguyen – Research/Miscellaneous Projects
SIP: Secure Information Provider Framework for Mobile Phone Users
The increasing power of the smart phone devices
have posed many challenges to the privacy of the information of
the device owner. Privacy has become of paramount importance
with the explosion of increasingly popular (but malicoius/curious)
mobile phone apps. In this research we provide a framework for
preventing malious services from accessing users data on his
mobile phone without his permission. We show the proposed
framework in action with the use of a music recommendation
service. We evaluate the usability of the service in presence of
our anonymizer framework.
Final project report
Information and Influence Spread on Social Networks
Influence maximization is the problem of finding
a small set of seed nodes in a social network that maximizes
the spread of influence under a certain diffusion model. The
Greedy algorithm for influence maximization first proposed by
Kempe, later improved by Leskovec suffers from two sources of
computational deficiency: 1) the need to evaluate many candidate
nodes before selecting a new seed in each round, and 2) the
calculation of the influence spread of any seed set relies on
Monte-Carlo simulations. In this work, we tackle both problems
by devising efficient algorithms to compute influence spread and
determine the best candidate for seed selection. The fundamental
insight behind the proposed algorithms is the linkage between
influence spread determination and belief propagation on a
directed acyclic graph (DAG). Experiments using real-world
social network graphs with scales ranging from thousands to
millions of edges demonstrate the superior performance of the
proposed algorithms with moderate computation costs.
Robust Resource Management in ISM Bands
Passive monitoring utilizing distributed wireless sniffers is an effective technique
to monitor activities in wireless infrastructure networks for fault diagnosis, resource
management and critical path analysis. In this research, we introduce a quality of monitoring
(QoM) metric defined by the expected number of active users monitored, and investigate
the problem of maximizing QoM by judiciously assigning sniffers to channels based on knowledge
of user activities in a multi-channel wireless network.
Two capture models are considered.
The first one, called the user-centric model assumes frame-level capturing capability of sniffers
such that the activities of different users can be distinguished. The second one, called the
sniffer-centric model only utilizes binary channel information (active or not) at a sniffer.
For the user-centric model, we show that the implied optimization problem is NP-hard, but a constant
approximation ratio can be attained via polynomial complexity algorithms. For the sniffer-centric
model, we devise a stochastic inference scheme that transforms the problem into the user-centric
domain, where we are able to apply our polynomial approximation algorithms. The effectiveness
of our proposed scheme and algorithms is further evaluated using both synthetic data as well as
real-world traces from an operational WLAN.
Mobihoc 2010 paper
Mobihoc 2010 presentation slides
Multicast Tree Topology Inference
Using multicast probes to infer network topologies and internal link/node characteristics
is an attractive approach due to its bandwidth efficiency and suitability for
large-scale measurements. In this research, we propose a new approach to infer
tree topologies by exploiting dependence among end-point receivers. We first
show that under the assumption of independent failure of intermediate nodes
or links, inferring tree topology is a special instance of the more general
problem of binary independent component analysis (bICA), and thus is amiable
to existing analytical results and algorithms for bICA. Then, we propose
seqBICA that is tailored for tree topology inference. Both analysis and
evaluation study show that the proposed algorithm outperforms existing
approaches in convergence speed and accuracy even when the number of
measurements is small.
Developing websites has been my hobby since I was an undergraduate student.
In this work, I use Drupal and MySQL database to remake WiSeR's website.
The Wireless System Research Group at the University of Houston conducts research on a variety of communication,
networking and system issues in Cyber Physical Systems. Our focus is on advancing the fundamental understanding
and development of efficient robust solutions. Our projects span core system building blocks, data and network
management tools and services, mathematical principles, and application of wireless communication and networking
to scientific, industrial and health-care disciplines. Our research is currently supported by National Science
Foundation , UH Grants to Enhance and Advance Research (GEAR), Defense University Research Instrumentation Program