9,800 research outputs found
Smart Pacing for Effective Online Ad Campaign Optimization
In targeted online advertising, advertisers look for maximizing campaign
performance under delivery constraint within budget schedule. Most of the
advertisers typically prefer to impose the delivery constraint to spend budget
smoothly over the time in order to reach a wider range of audiences and have a
sustainable impact. Since lots of impressions are traded through public
auctions for online advertising today, the liquidity makes price elasticity and
bid landscape between demand and supply change quite dynamically. Therefore, it
is challenging to perform smooth pacing control and maximize campaign
performance simultaneously. In this paper, we propose a smart pacing approach
in which the delivery pace of each campaign is learned from both offline and
online data to achieve smooth delivery and optimal performance goals. The
implementation of the proposed approach in a real DSP system is also presented.
Experimental evaluations on both real online ad campaigns and offline
simulations show that our approach can effectively improve campaign performance
and achieve delivery goals.Comment: KDD'15, August 10-13, 2015, Sydney, NSW, Australi
A Software-Defined Channel Sounder for Industrial Environments with Fast Time Variance
Novel industrial wireless applications require wideband, real-time channel
characterization due to complex multipath propagation. Rapid machine motion
leads to fast time variance of the channel's reflective behavior, which must be
captured for radio channel characterization. Additionally, inhomogeneous radio
channels demand highly flexible measurements. Existing approaches for radio
channel measurements either lack flexibility or wide-band, real-time
performance with fast time variance. In this paper, we propose a correlative
channel sounding approach utilizing a software-defined architecture. The
approach enables real-time, wide-band measurements with fast time variance
immune to active interference. The desired performance is validated with a
demanding industrial application example.Comment: Submitted to the 15th International Symposium on Wireless
Communication Systems (ISWCS 2018
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The evaluation of effectiveness of school-based small group mentoring system : Discovery Scholars Program at UT Austin
Previous studies have found that students’ college experiences differ vastly depending on their socioeconomic status (SES), not only in their academic achievement (Chen & Carroll, 2005; Harackiewicz et al., 2014), but also in the wholesome process of the college experience, including college preparation and socio-cultural practices while at college (Engle & Tinto, 2008; Merritt, 2008). The present study examines the effectiveness of a small-group mentoring program, Discovery Scholars Program, targeted for students identified as at-risk due to SES and lower entrance scores at the University of Texas at Austin. Through exploring the survey data collected as part of the program, the current study explored the following research questions: 1) Did the students engage in and benefit from DSP events and feel supported by the DSP groups? 2) Did the DSP program help students develop academic skills necessary for college life? 3) Did the DSP program help students feel more comfortable and confident as a part of the UT community? The results showed that, while more long-term goals of the program were difficult to measure, the program succeeded in helping students develop social support groups and academic skills that aided in their adjustment process to college.Educational Psycholog
PI-BA Bundle Adjustment Acceleration on Embedded FPGAs with Co-observation Optimization
Bundle adjustment (BA) is a fundamental optimization technique used in many
crucial applications, including 3D scene reconstruction, robotic localization,
camera calibration, autonomous driving, space exploration, street view map
generation etc. Essentially, BA is a joint non-linear optimization problem, and
one which can consume a significant amount of time and power, especially for
large optimization problems. Previous approaches of optimizing BA performance
heavily rely on parallel processing or distributed computing, which trade
higher power consumption for higher performance. In this paper we propose
{\pi}-BA, the first hardware-software co-designed BA engine on an embedded
FPGA-SoC that exploits custom hardware for higher performance and power
efficiency. Specifically, based on our key observation that not all points
appear on all images in a BA problem, we designed and implemented a
Co-Observation Optimization technique to accelerate BA operations with
optimized usage of memory and computation resources. Experimental results
confirm that {\pi}-BA outperforms the existing software implementations in
terms of performance and power consumption.Comment: in Proceedings of IEEE FCCM 201
Symbol Synchronization for SDR Using a Polyphase Filterbank Based on an FPGA
This paper is devoted to the proposal of a highly efficient symbol synchronization subsystem for Software Defined Radio. The proposed feedback phase-locked loop timing synchronizer is suitable for parallel implementation on an FPGA. The polyphase FIR filter simultaneously performs matched-filtering and arbitrary interpolation between acquired samples. Determination of the proper sampling instant is achieved by selecting a suitable polyphase filterbank using a derived index. This index is determined based on the output either the Zero-Crossing or Gardner Timing Error Detector. The paper will extensively focus on simulation of the proposed synchronization system. On the basis of this simulation, a complete, fully pipelined VHDL description model is created. This model is composed of a fully parallel polyphase filterbank based on distributed arithmetic, timing error detector and interpolation control block. Finally, RTL synthesis on an Altera Cyclone IV FPGA is presented and resource utilization in comparison with a conventional model is analyzed
Complex Dynamics and Synchronization of Delayed-Feedback Nonlinear Oscillators
We describe a flexible and modular delayed-feedback nonlinear oscillator that
is capable of generating a wide range of dynamical behaviours, from periodic
oscillations to high-dimensional chaos. The oscillator uses electrooptic
modulation and fibre-optic transmission, with feedback and filtering
implemented through real-time digital-signal processing. We consider two such
oscillators that are coupled to one another, and we identify the conditions
under which they will synchronize. By examining the rates of divergence or
convergence between two coupled oscillators, we quantify the maximum Lyapunov
exponents or transverse Lyapunov exponents of the system, and we present an
experimental method to determine these rates that does not require a
mathematical model of the system. Finally, we demonstrate a new adaptive
control method that keeps two oscillators synchronized even when the coupling
between them is changing unpredictably.Comment: 24 pages, 13 figures. To appear in Phil. Trans. R. Soc. A (special
theme issue to accompany 2009 International Workshop on Delayed Complex
Systems
A Survey of Techniques For Improving Energy Efficiency in Embedded Computing Systems
Recent technological advances have greatly improved the performance and
features of embedded systems. With the number of just mobile devices now
reaching nearly equal to the population of earth, embedded systems have truly
become ubiquitous. These trends, however, have also made the task of managing
their power consumption extremely challenging. In recent years, several
techniques have been proposed to address this issue. In this paper, we survey
the techniques for managing power consumption of embedded systems. We discuss
the need of power management and provide a classification of the techniques on
several important parameters to highlight their similarities and differences.
This paper is intended to help the researchers and application-developers in
gaining insights into the working of power management techniques and designing
even more efficient high-performance embedded systems of tomorrow
A survey of fuzzy control for stabilized platforms
This paper focusses on the application of fuzzy control techniques (fuzzy
type-1 and type-2) and their hybrid forms (Hybrid adaptive fuzzy controller and
fuzzy-PID controller) in the area of stabilized platforms. It represents an
attempt to cover the basic principles and concepts of fuzzy control in
stabilization and position control, with an outline of a number of recent
applications used in advanced control of stabilized platform. Overall, in this
survey we will make some comparisons with the classical control techniques such
us PID control to demonstrate the advantages and disadvantages of the
application of fuzzy control techniques
Software Defined Radio Implementation of Carrier and Timing Synchronization for Distributed Arrays
The communication range of wireless networks can be greatly improved by using
distributed beamforming from a set of independent radio nodes. One of the key
challenges in establishing a beamformed communication link from separate radios
is achieving carrier frequency and sample timing synchronization. This paper
describes an implementation that addresses both carrier frequency and sample
timing synchronization simultaneously using RF signaling between designated
master and slave nodes. By using a pilot signal transmitted by the master node,
each slave estimates and tracks the frequency and timing offset and digitally
compensates for them. A real-time implementation of the proposed system was
developed in GNU Radio and tested with Ettus USRP N210 software defined radios.
The measurements show that the distributed array can reach a residual frequency
error of 5 Hz and a residual timing offset of 1/16 the sample duration for 70
percent of the time. This performance enables distributed beamforming for range
extension applications.Comment: Submitted to 2019 IEEE Aerospace Conferenc
Fast Adaptive Robust Differentiator Based Robust-Adaptive Control of Grid-Tied Inverters with a New L Filter Design Method
In this research, a new nonlinear and adaptive state feedback controller with a fast-adaptive robust differentiator is presented for grid-tied inverters. All parameters and external disturbances are taken as uncertain in the design of the proposed controller without the disadvantages of singularity and over-parameterization. A robust differentiator based on the second order sliding mode is also developed with a fast-adaptive structure to be able to consider the time derivative of the virtual control input. Unlike the conventional backstepping, the proposed differentiator overcomes the problem of explosion of complexity. In the closed-loop control system, the three phase source currents and direct current (DC) bus voltage are assumed to be available for feedback. Using the Lyapunov stability theory, it is proven that the overall control system has the global asymptotic stability. In addition, a new simple L filter design method based on the total harmonic distortion approach is also proposed. Simulations and experimental results show that the proposed controller assurances drive the tracking errors to zero with better performance, and it is robust against all uncertainties. Moreover, the proposed L filter design method matches the total harmonic distortion (THD) aim in the design with the experimental result
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