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Non-traditional ADC and DAC testing with poly-harmonic signals
Vedral, Josef; Holub, Jan; Fexa, Pavel
2015 - English
This thesis summarizes the results from research in the field of dynamic testing Analog to Digital and Digital to Analog Converters using poly-harmonic signals.
The aim of the work is to analyze and verify properties of non-traditional methods for dynamic converters testing. The goal is to measure these parameters effectively and quickly in broader frequency range at the same time. When searching for new methods, this work was inspired with Amplitude Modulated, Frequency Modulated signals, Multi-Tone signals with Uniformly Distributed Amplitude Spectral Lines, and impulse signals such as Damped Sine Wave and (sinx/x) signal.
Previously mentioned signals were chosen to reflect measurement or generation in the real conditions. Modulated and Multi-Tone signals are common signals in radio engineering. A Damped Sine Wave signal corresponds with a step response of the second order system. Sinc (sinx/x) signal contains uniformly distributed amplitude lines in its frequency spectrum.
Signals which are stated here have one common link. Their amplitude spectra contain more than one frequency. This feature gives us complex information in one measurement and significantly reduces the time for estimation of converter’s dynamic parameters. This fact is significant in end of line testing during manufacturing of converters.
Attributes of new proposed methods using multi-harmonic signals were analyzes theoretically then simulated and finally verified by measurement on the real devices like digitizers or generators.
Results from tests using Multi-Tone signals are evaluated both in time domain and frequency domain. The dynamic parameters Effective Number of Bits (ENOB) and Signal to Noise and Distortion (SINAD) were chosen as the main parameters for methods evaluation.
Non-traditional test’s results are compared with results from standard methods like Best Sine Wave Fit Test evaluating converters in time domain or Sine Wave DFT Test testing converters in frequency domain according to a standards IEEE 1241 and IEEE1658.
The
Available in digital repository of ČVUT.
Non-traditional ADC and DAC testing with poly-harmonic signals
This thesis summarizes the results from research in the field of dynamic testing Analog to Digital and Digital to Analog Converters using poly-harmonic signals. The aim of the work is to analyze and ...
Advanced Methods and Models for Employee Timetabling Problems
Hanzálek. Zdeněk; Šůcha, Přemysl; Bäumelt, Zdeněk
2015 - English
This thesis is focused on the design of efficient models and algorithms for
employee timetabling problems (ETPs). From our point of view, there are two
significant gaps in the current state of the art.
The first one, also important in practice, concerns the ETP with strongly
varying workforce demand. Unlike the classical Nurse Rostering Problem
(NRP) this problem considers dozens of shift types that can cover the demand
more precisely than early, late and night shift type used in NRP. In
this work we call this problem the Employee Timetabling Problem with a High
Diversity of shifts (ETPHD). It comes as no surprise that the exact methods
like Integer Linear Programming are not able to find its solution in reasonable
time. Therefore, a transformation of ETPHD based on mapping of shift
types to shift kinds was proposed. The transformation allows one to design a
multistage approach (MSA). The aim of the first two stages is to find an initial
ETPHD solution, where a rough position of assigned shifts is determined.
This proved to be substantial for the last stage of MSA, where the solution
is consequently improved in terms of its quality. In order to verify the MSA
performance, a cross evaluation methodology was proposed. It is based on the
comparison of the performance provided by more approaches on more combinatorial
problems. Therefore, real life ETPHD instances from an airport ground
company and also standard benchmark NRP instances were considered. The
experiments confirmed the better or equal performance of our approach in the
most of the cases.
The second gap in the literature is an absence of parallel algorithms for
ETPs. We focused on the Nurse Rerostering Problem (NRRP) that appears
when a disruption in the roster occurs, e.g., when one of the employees becomes
sick. For this purpose, the parallel algorithm solving NRRP was proposed in
order to shorten needed computational time. This algorithm was designed for a
Graphics Processing Unit (GPU) offering a massive parallelization. To the best
of our knowledge, this is the first usage of GPU for ETPs. The performance
of the GPU parallel algorithm was tested on the real life NRRP benchmark
instances and evaluated from two points of view. Firstly, the quality of the
results was compared to the known results from the state of the art. Secondly,
the speedup achieved by the parallel algorithm related to the sequential one
was verified. In average, the parallel algorithm is able to provide the results of
the same quality 15 times faster than the sequential one.
Available in digital repository of ČVUT.
Advanced Methods and Models for Employee Timetabling Problems
This thesis is focused on the design of efficient models and algorithms for employee timetabling problems (ETPs). From our point of view, there are two significant gaps in the current state of the ...
Algebraic computations in quantum logics
Navara, Mirko; Gabriëls, Jeannine J. M.
2015 - English
Mathematical description of quantum phenomena requires an event structure more general
than a Boolean algebra. For this purpose, Birkhoff and von Neumann proposed
the notion of an orthomodular lattice. Its typical feature is the existence of so–called
non–commuting events, which are not simultaneously observable (like position and momentum,
according to Heisenberg’s uncertainty principle).
There is an old open problem whether the word problem for orthomodular lattices
is solvable. Is it possible to decide whether two formulas are equivalent? In Boolean
algebras, an easy positive answer is given by a transformation of the formula to a unique
normal form. This requires the commutativity, associativity, and distributivity of the
Boolean operations (disjunction and conjunction).
In orthomodular lattices, the corresponding lattice operations (join and meet) violate
distributivity. This disables the use of normal forms. We looked for alternative approaches.
E.g., the join is only one of six orthomodular lattice operations generalizing
the disjunction. In the thesis, we study the question whether some of the 96 binary
operations in orthomodular lattices admit normal forms similar to the classical logic.
The first question was which operations satisfy the associative identity, eventually
under the assumption that some variables commute. Then we studied monotonicity
because it is related to distributivity over the meet and join. The conclusion is that
there is no pair of operations in orthomodular lattices admitting “Boolean–like” normal
forms. In the last chapter we study “Moufang–like” identities, which were inspired by
the algebras of quaternions and octonions. These identities generalize associativity and
may enable further progress.
As a by–product, we proved interesting, yet unknown, properties of some orthomodular
lattice operations (e.g., the Sasaki projection). These new tools simplify algebraic
computations and give a chance to develop algorithms more general than the current
specialized software.
Available in digital repository of ČVUT.
Algebraic computations in quantum logics
Mathematical description of quantum phenomena requires an event structure more general than a Boolean algebra. For this purpose, Birkhoff and von Neumann proposed the notion of an orthomodular ...
On Concern-separation of Data Presentations in User Interfaces
Janoušek, Jan; Donahoo J. Michael; Černý, Tomáš
2015 - English
Available in digital repository of ČVUT.
On Concern-separation of Data Presentations in User Interfaces
Description and Generation of Large-Amplitude Acoustic Fields in Closed Spaces
Bednařík, Michal; Červenka, Milan; Šoltés, Martin
2015 - English
Available in digital repository of ČVUT.
Description and Generation of Large-Amplitude Acoustic Fields in Closed Spaces
Risk Management Methods for Industrial Systems
Bílek, Jan; Ferkl, Lukáš; Nývlt, Ondřej
2015 - English
Risk management (RM) is today a commonly used term in many different disciplines (e.g.
economy, industry, human resources, IT). Its goal is firstly to identify risks (e.g. of a machine
operation, human behaviour or of a whole project) which can cause harm to properties, persons
or environment. Secondly the RM should evaluate probabilities and severities of these unwanted
events and propose measures for their elimination or a reduction of their impact. This whole
process should be periodically repeated to assess influences of the measures of a risk control on
detected risks. If the risks are mitigated insufficiently, then there should be additional measures
proposed.
This general interdisciplinary approach could be split into three parts or phases. This Ph.D.
thesis is focused on the first phase: the risk analysis (RA). There are few commonly used
traditional RA methods in the industry area e.g. Fault Tree Analysis (FTA) or Event Tree
Analysis (ETA). These methods were developed many years ago, so their original definitions do
not meet today’s requirements for analysis of large and complex systems or accidental scenarios
with different types of dependencies, dynamic changes and other pitfalls. Different industrial
areas have developed their own narrowly focused methods during last years, even though there
could be, for selected tasks, used some of the mentioned common, but slightly modified methods.
Based on the stated facts, this Ph.D. thesis is focused on an analysis of traditional RA methods,
on a detection of their specific problems and mainly on a proposal of new alternative universal
methods which are able to solve the mentioned problems. These new methods should integrate
more than two phases of the RA together and they have to be practically usable. As a framework
for a design of new methods, Petri nets (PN) were chosen. They are often used for a modelling
and analysis of discrete event systems (DES), but they are still not common in the area of the RA.
The first part of the thesis shows how advantageous it is to use general (in this case traditional)
methods instead of the narrowly focused ones. As an example, a risk analysis of the Strahov city
road tunnel is chosen. The goal of the analysis is to select which option of a reconstruction of
the tunnel is the best from the point of view of the risk/cost ratio. A slightly modified general
analysis called Probabilistic Risk Assessment, which is known from the nuclear and aerospace
industry, provides superb results and supports the idea of using non-specialized methods.
The second part of the thesis introduces a concept of the PN as a tool for a solution of selected
problems of traditional RA methods. The non-marked PN are used for a theoretical solution of
dependencies of pivotal events in the ETA.
The final part of the thesis presents a proposal of a new alternative complex RA method
based on stochastic PN, which is able to model the whole accidental scenario without pitfalls
of the traditional FTA and ETA. It extends a classical approach with an ability to easily model
dependencies and dynamic changes of an event sequence in the scenario. This method is fully
usable and is supported by existing commercial software tools.
This doctoral thesis demonstrates that the PN are still a little bit overlooked but powerful
framework for risk analysis and management and offer new possibilities for modelling, simulation
and analysis.
Keywords:
Risk management; Risk analysis; Petri nets; Road tunnels; Fault trees; Event trees
Available in digital repository of ČVUT.
Risk Management Methods for Industrial Systems
Risk management (RM) is today a commonly used term in many different disciplines (e.g. economy, industry, human resources, IT). Its goal is firstly to identify risks (e.g. of a machine operation, ...
Global Optimization Techniques in Camera-Robot Calibration
Pajdla, Tomáš; Heller, Jan
2015 - English
The need to relate measurements made by a camera to a different known coordinate system
arises in many engineering applications. Historically, it appeared for the first time in the
connection with cameras mounted on robotic systems. This problem is commonly known as
hand-eye calibration. In this thesis, we study the problem of hand-eye calibration as well as
a problem closely connected to it—the problem of robot-world calibration. The first objective
of this work is to apply recent results in mathematical optimization to provide globally
optimal solution to these problems. The second objective is to formulate and study these
problems as minimization problems under some geometrically meaningful error measures
using image measurements directly. We also study global optimizers in situation where image
measurements are not available using the classical problem formulations. The solutions
presented in this thesis are compared to existing methods and validated by both synthetic and
real world data experiments.
In the first part of the thesis, we survey the state of the art of the camera-robot calibration
as well as of the main concepts of the geometrical computer vision. Further, we review
several results in the globally optimization techniques and their application in the computer
vision.
Next, we formulate the problem of hand-eye calibration as a minimization problem under
some geometrically meaningful error measures. We provide two solutions; the first solution
employs a Structure-from-Motion approach and the Second Order Cone Programming optimization
and the second one uses the Brand-and-Bound optimization strategy. Both solutions
provide globally optimal minimizers and work with image measurements directly, instead of
using them as a pre-step for explicitly calculating camera poses. Using a similar approach,
we also formulate a minimization task for the robot-world calibration problem. This time, to
solve the task we use the method of Linear Matrix Inequality relaxations.
Further, we investigate the problem of hand-eye calibration in situations, where the information
about the rotation of the robot is not known. This problem arises when the robot
is not calibrated or the information from the robot is not available. We use the method of
Gröbner basis to deal with this scenario.
Finally, we revisit the classical formulation of the hand-eye and robot-world calibration.
Using the method of Linear Matrix Inequality relaxations, we provide several global optimizers
in situations, where image measurements are not available and the calibration has to
be estimated from robot and camera poses only.
Available in digital repository of ČVUT.
Global Optimization Techniques in Camera-Robot Calibration
The need to relate measurements made by a camera to a different known coordinate system arises in many engineering applications. Historically, it appeared for the first time in the connection with ...
Scheduling with Alternative Process Plans
Hanzálek, Zdeněk; Šůcha, Přemysl; Čapek, Roman
2015 - English
Available in digital repository of ČVUT.
Scheduling with Alternative Process Plans
Spike Sorting of Microelectrode Single-channel Recordings
Novák, Daniel; Štěpánková, Olga; Wild, Jiří
2015 - English
Until now the experimental research in medical neuroscience has been limited to analyzing
summary activity of large neuron populations. However, thanks to recent e orts in using
neuroinformatics, arti cial intelligence and machine learning methods in neuroscience
as well as medical and technological advances, new opportunities to record activity of
individual neurons arises. These opportunities allow us to better understand the neural
mechanism of complex behavior, as well as identify parts of the brain responsible for
speci c tasks.
In this thesis, we were focusing on applying such methods to data recorded from patients
with Parkinson's disease that were treated with deep brain stimulation, to improve
our understanding of the human brain and the mechanism of the deep brain stimulation
in particular.
This thesis concentrated mainly on two problems in this eld. First, the evaluation
of the state-of-the-art methods used to identify and classify neuronal action potentials
(i.e spike sorting methods) in microelectrode recordings, which required devising and
implementation of signal generator that produced arti cial signals with similar properties
as the signals recorded from basal ganglia.
Second, to use these methods to discriminate individual neurons from a microelectrode
recording and to use this knowledge to identify neurons with speci c functions in
basal ganglia and better understanding of the human brain in general. Spike sorting
methods allowed us to nd approx. 20% of basal ganglia neurons with activity related to
control of eye movements and 17% of basal ganglia neurons with activity related to processing
emotional stimuli or responding to di erent types of emotional stimuli. We were
also able to nd several statistically signi cant relations between severity of Parkinson's
disease symptoms (described using Uni ed Parkinson's Disease Rating Scale subscores)
and statistical characteristics of both microelectrode records and by individual neuron
ring patterns using linear mixed-e ects models.
Available in digital repository of ČVUT.
Spike Sorting of Microelectrode Single-channel Recordings
Until now the experimental research in medical neuroscience has been limited to analyzing summary activity of large neuron populations. However, thanks to recent e orts in using neuroinformatics, ...
Bioimpedance measurement of specific body resistance
Lhotská, Lenka; Hlúbik, Jan
2015 - English
Available in digital repository of ČVUT.
Bioimpedance measurement of specific body resistance
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