561 research outputs found
The Fundamentals of Radar with Applications to Autonomous Vehicles
Radar systems can be extremely useful for applications in autonomous vehicles. This paper seeks to show how radar systems function and how they can apply to improve autonomous vehicles. First, the basics of radar systems are presented to introduce the basic terminology involved with radar. Then, the topic of phased arrays is presented because of their application to autonomous vehicles. The topic of digital signal processing is also discussed because of its importance for all modern radar systems. Finally, examples of radar systems based on the presented knowledge are discussed to illustrate the effectiveness of radar systems in autonomous vehicles
Cross-layer design of multi-hop wireless networks
MULTI -hop wireless networks are usually defined as a collection of nodes
equipped with radio transmitters, which not only have the capability to
communicate each other in a multi-hop fashion, but also to route each others’ data
packets. The distributed nature of such networks makes them suitable for a variety of
applications where there are no assumed reliable central entities, or controllers, and
may significantly improve the scalability issues of conventional single-hop wireless
networks.
This Ph.D. dissertation mainly investigates two aspects of the research issues
related to the efficient multi-hop wireless networks design, namely: (a) network
protocols and (b) network management, both in cross-layer design paradigms to
ensure the notion of service quality, such as quality of service (QoS) in wireless mesh
networks (WMNs) for backhaul applications and quality of information (QoI) in
wireless sensor networks (WSNs) for sensing tasks. Throughout the presentation of
this Ph.D. dissertation, different network settings are used as illustrative examples,
however the proposed algorithms, methodologies, protocols, and models are not
restricted in the considered networks, but rather have wide applicability.
First, this dissertation proposes a cross-layer design framework integrating
a distributed proportional-fair scheduler and a QoS routing algorithm, while using
WMNs as an illustrative example. The proposed approach has significant performance
gain compared with other network protocols. Second, this dissertation proposes
a generic admission control methodology for any packet network, wired and
wireless, by modeling the network as a black box, and using a generic mathematical
0. Abstract 3
function and Taylor expansion to capture the admission impact. Third, this dissertation
further enhances the previous designs by proposing a negotiation process,
to bridge the applications’ service quality demands and the resource management,
while using WSNs as an illustrative example. This approach allows the negotiation
among different service classes and WSN resource allocations to reach the optimal
operational status. Finally, the guarantees of the service quality are extended to
the environment of multiple, disconnected, mobile subnetworks, where the question
of how to maintain communications using dynamically controlled, unmanned data
ferries is investigated
Energy-Efficient Power Control for Contention-Based Synchronization in OFDMA Systems with Discrete Powers and Limited Feedback
This work derives a distributed and iterative algorithm by which mobile
terminals can selfishly control their transmit powers during the
synchronization procedure specified by the IEEE 802.16m and the 3GPP-LTE
standards for orthogonal frequency-division multiple-access technologies. The
proposed solution aims at maximizing the energy efficiency of the network and
is derived on the basis of a finite noncooperative game in which the players
have discrete action sets of transmit powers. The set of Nash equilibria of the
game is investigated, and a distributed power control algorithm is proposed to
achieve synchronization in an energy-efficient manner under the assumption that
the feedback from the base station is limited. Numerical results show that the
proposed solution improves the energy efficiency as well as the timing
estimation accuracy of the network compared to existing alternatives, while
requiring a reasonable amount of information to be exchanged on the return
channel
Quadratic optimal functional quantization of stochastic processes and numerical applications
In this paper, we present an overview of the recent developments of
functional quantization of stochastic processes, with an emphasis on the
quadratic case. Functional quantization is a way to approximate a process,
viewed as a Hilbert-valued random variable, using a nearest neighbour
projection on a finite codebook. A special emphasis is made on the
computational aspects and the numerical applications, in particular the pricing
of some path-dependent European options.Comment: 41 page
American Options Based on Malliavin Calculus and Nonparametric Variance Reduction Methods
This paper is devoted to pricing American options using Monte Carlo and the
Malliavin calculus. Unlike the majority of articles related to this topic, in
this work we will not use localization fonctions to reduce the variance. Our
method is based on expressing the conditional expectation E[f(St)/Ss] using the
Malliavin calculus without localization. Then the variance of the estimator of
E[f(St)/Ss] is reduced using closed formulas, techniques based on a
conditioning and a judicious choice of the number of simulated paths. Finally,
we perform the stopping times version of the dynamic programming algorithm to
decrease the bias. On the one hand, we will develop the Malliavin calculus
tools for exponential multi-dimensional diffusions that have deterministic and
no constant coefficients. On the other hand, we will detail various
nonparametric technics to reduce the variance. Moreover, we will test the
numerical efficiency of our method on a heterogeneous CPU/GPU multi-core
machine
Goal-Oriented Quantization: Analysis, Design, and Application to Resource Allocation
In this paper, the situation in which a receiver has to execute a task from a
quantized version of the information source of interest is considered. The task
is modeled by the minimization problem of a general goal function for
which the decision has to be taken from a quantized version of the
parameters . This problem is relevant in many applications e.g., for radio
resource allocation (RA), high spectral efficiency communications, controlled
systems, or data clustering in the smart grid. By resorting to high resolution
(HR) analysis, it is shown how to design a quantizer that minimizes the gap
between the minimum of (which would be reached by knowing perfectly)
and what is effectively reached with a quantized . The conducted formal
analysis both provides quantization strategies in the HR regime and insights
for the general regime and allows a practical algorithm to be designed. The
analysis also allows one to provide some elements to the new and fundamental
problem of the relationship between the goal function regularity properties and
the hardness to quantize its parameters. The derived results are discussed and
supported by a rich numerical performance analysis in which known RA goal
functions are studied and allows one to exhibit very significant improvements
by tailoring the quantization operation to the final task
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