<p>This master thesis has been performed at Sectra Communications AB in Linköping where they manufacture electronic encryption devices. In cryptology it is essential that an eavesdropper cannot find the plain text. To assure that a system is safe, all devices are thoroughly examined so that they don’t emit any secret information, so called Compromising Emanations (CE). This is done by comparing the secret signal with measured signals on the screen of an oscilloscope, a process that is very time consuming and furthermore, the risk of missing compromising emanations is high. The purpose of this thesis is to investigate the possibilities to let a computer do this job. Two methods for comparing the signals have been suggested and implemented; cross covariance and model estimation. In the cross covariance method, the cross covariance is calculated and its highest value determine how well the signals match. In the model estimation method, a number of ARX models are estimated, and if the best model is successful in explaining the output signal, it is assumed that there exists CE. </p><p>The work shows that both these methods are functional for solving the task, yet with a few limitations. Both methods announce CE for clock signals, which really aren’t compromising. The cross covariance method is limited only to find compromising emanations that look like the secret signal or certain frequently occurring non-linearities of it. The model estimation method is more general and detects CE for all linear systems, along with the known non-linearities. However, this method has a flaw: the time delay in the system must be known approximately. Further, the results show that the model estimation method is considerably more time consuming than the cross covariance method. The measurement is carried out with a computer communicating with oscilloscope and spectrum analyzer via the GPIB interface. The implementation has been done in LabView with calculation modules coded in C++.</p>

Rotordynamic instability can be disastrous for the operation of high speed turbomachinery in the industry. Most ??instabilities?? are due to de-stabilizing cross coupled forces from variable fluid dynamic pressure around a rotor component, acting in the direction of the forward whirl and causing subsynchronous orbiting of the rotor. However, all subsynchronous whirling is not unstable and methods to diagnose the potentially unstable kind are critical to the health of the rotor-bearing system. The objective of this thesis is to explore means of diagnosing whether subsynchronous vibrations are benign or have the potential to become unstable. Several methods will be detailed to draw lines of demarcation between the two. Considerable focus of the research has been on subharmonic vibrations induced from non-linear bearing stiffness and the study of vibration signals typical to such cases. An analytical model of a short-rigid rotor with stiffness non-linearity is used for numerical simulations and the results are verified with actual experiments. Orbits filtered at the subsynchronous frequency are shown as a diagnostic tool to indicate benign vibrations as well as ??frequency tracking?? and agreement of the frequency with known eigenvalues. Several test rigs are utilized to practically demonstrate the above conclusions. A remarkable finding has been the possibility of diagnosing instability using the synchronous phase angle. The synchronous phase angle ?? is the angle by which the unbalance vector leads the vibration vector. Experiments have proved that ?? changes appreciably when there is a de-stabilizing cross coupled force acting on the rotor as compared to when there is none. A special technique to calculate the change in ?? with cross-coupling is outlined along with empirical results to exemplify the case. Subsequently, a correlation between the synchronous phase angle and the phase angle measured with most industrial balancing instruments is derived so that the actual measurement of the true phase angle is not a necessity for diagnosis. Requirements of advanced signal analysis techniques have led to the development of an extremely powerful rotordynamic measurement teststand ?? ??LVTRC??. The software was developed in tandem with this thesis project. It is a stand-alone application that can be used for field measurements and analysis by turbomachinery companies.

Although the major functions of the lymphatic system are fairly well defined, its vasculature has yet to be well characterized in comparison to its blood vasculature counterpart. Recent advances in optical imaging techniques have allowed for more detailed and quantitative evaluations of lymph flow dynamics and mechanism. A rat tail is often used for investigations of lymph flow because of the simple geometry, superficial nature, and disease progression models of its collecting lymphatic vessels. In this study, a pressure cuff system was fabricated and coupled with an existing functional near infrared (NIR) imaging system to measure the overall pumping pressure of the lymphatic vessels of a rat tail. In addition to adapting the system for use on rodents, previous systems used for measuring lymphatic pumping pressure in humans were improved upon in several ways. The system defined here utilizes closed-loop feedback control of pressure application at smaller, more precise intervals. Using this device, a significant difference in lymphatic vessel pumping pressure was detected between a control case and a treatment case in which a vasoactive substance with a nitric oxide donor (GTNO ointment) was applied to the tail. Although it is known that nitric oxide plays a crucial physiologic role in propagation of flow through lymphatic vessels, this study has quantified its significant pharmacological reduction of pumping pressure for the first time.

A measurement system is to be presented, which is used to obtain the I-V characteristics of a solar cell and to track its temperature during irra-diation before mounting it into a complete array/module. This project presents both the design and implementation of an Electronic load for testing the solar cell under field conditions of 10000 W/m^2, which is able to provide current versus voltage and power versus voltage charac-teristics of a solar cell using a software based model developed in Lab-VIEW. An efficient water cooling method which includes a heat pipe array system is also suggested. This thesis presents the maximum power tracking of a solar cell and the corresponding voltage and current values. In addition, the design of the clamp system provides an easy means of replacing the solar cell during testing.Keywords: Solar cell, Metal Oxide Semiconductor Field Effect Transistor (MOSFET), I-V characteristics, cooling system, solar cell clamp system, LabVIEW, Graphical User Interface (GUI).

This master thesis has been performed at Sectra Communications AB in Linköping where they manufacture electronic encryption devices. In cryptology it is essential that an eavesdropper cannot find the plain text. To assure that a system is safe, all devices are thoroughly examined so that they don’t emit any secret information, so called Compromising Emanations (CE). This is done by comparing the secret signal with measured signals on the screen of an oscilloscope, a process that is very time consuming and furthermore, the risk of missing compromising emanations is high. The purpose of this thesis is to investigate the possibilities to let a computer do this job. Two methods for comparing the signals have been suggested and implemented; cross covariance and model estimation. In the cross covariance method, the cross covariance is calculated and its highest value determine how well the signals match. In the model estimation method, a number of ARX models are estimated, and if the best model is successful in explaining the output signal, it is assumed that there exists CE. The work shows that both these methods are functional for solving the task, yet with a few limitations. Both methods announce CE for clock signals, which really aren’t compromising. The cross covariance method is limited only to find compromising emanations that look like the secret signal or certain frequently occurring non-linearities of it. The model estimation method is more general and detects CE for all linear systems, along with the known non-linearities. However, this method has a flaw: the time delay in the system must be known approximately. Further, the results show that the model estimation method is considerably more time consuming than the cross covariance method. The measurement is carried out with a computer communicating with oscilloscope and spectrum analyzer via the GPIB interface. The implementation has been done in LabView with calculation modules coded in C++.

In recent years, smart gird has received much attention, and many researchers have devoted to home area network (HAN) to improve the efficiency of grid. This thesis proposes a bidirectional isolated DC-DC converter (Dual Active Bridge, DAB) with phase shift control to implement the concept of HAN. Li+Fe battery is used as storage device of the converter, and a bidirectional communication between Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) and Digital Signal Processor (DSP) is realized by CAN-bus. By setting the current command given by LabVIEW system, the converter is able to charge the Li+Fe battery with constant current and constant voltage method as well as discharge the Li+Fe battery with constant current. Operation principle of the converter and the associated loss are presented.

This work focuses on modeling, parameter estimation, and real-time position control of a two axis Gimbaled Mirror System (GMS) which is designed and manufactured to move an IR spot generated by an Infra Red Scene Generator System (IRSGS) in two orthogonal axes (elevation and azimuth) within the IR scene which is also generated by the IRSGS. Mathematical models of the GMS, the control system, and the disturbance torque originated from the movements of Flight Motion Simulator (FMS), on which the IRSGS will be mounted, are constructed using MATLAB&reg / /Simulink&reg / and MATLAB/Simulink/SimMechanics&reg / . Parameter estimations of the GMS and control system elements are achieved using MATLAB/Simulink Parameter Estimation Tool&reg / . The controller tuning is performed using the developed mathematical models in MATLAB/Simulink environment. Optimized digital PID controllers are implemented in the real-time control system. Performances of the controllers for both GMS axes are evaluated by both real system tests and simulation runs / and the results of these runs are compared. Controller performances under the effect of disturbances are analyzed by using the mathematical models developed in the MATLAB/ Simulink environment.

Rotordynamic instability can be disastrous for the operation of high speed turbomachinery in the industry. Most ??instabilities?? are due to de-stabilizing cross coupled forces from variable fluid dynamic pressure around a rotor component, acting in the direction of the forward whirl and causing subsynchronous orbiting of the rotor. However, all subsynchronous whirling is not unstable and methods to diagnose the potentially unstable kind are critical to the health of the rotor-bearing system. The objective of this thesis is to explore means of diagnosing whether subsynchronous vibrations are benign or have the potential to become unstable. Several methods will be detailed to draw lines of demarcation between the two. Considerable focus of the research has been on subharmonic vibrations induced from non-linear bearing stiffness and the study of vibration signals typical to such cases. An analytical model of a short-rigid rotor with stiffness non-linearity is used for numerical simulations and the results are verified with actual experiments. Orbits filtered at the subsynchronous frequency are shown as a diagnostic tool to indicate benign vibrations as well as ??frequency tracking?? and agreement of the frequency with known eigenvalues. Several test rigs are utilized to practically demonstrate the above conclusions. A remarkable finding has been the possibility of diagnosing instability using the synchronous phase angle. The synchronous phase angle ?? is the angle by which the unbalance vector leads the vibration vector. Experiments have proved that ?? changes appreciably when there is a de-stabilizing cross coupled force acting on the rotor as compared to when there is none. A special technique to calculate the change in ?? with cross-coupling is outlined along with empirical results to exemplify the case. Subsequently, a correlation between the synchronous phase angle and the phase angle measured with most industrial balancing instruments is derived so that the actual measurement of the true phase angle is not a necessity for diagnosis. Requirements of advanced signal analysis techniques have led to the development of an extremely powerful rotordynamic measurement teststand ?? ??LVTRC??. The software was developed in tandem with this thesis project. It is a stand-alone application that can be used for field measurements and analysis by turbomachinery companies.

An Inverted double pendulum is a combination of two individual pendulums which represents an example of a nonlinear and unstable dynamic system and it is also a good example of a physical system which can exhibit chaotic behavior.This document contains a first analysis of the model and the control of this system. Also presented is the installation of the electrical materials needed to control the system contain instrumenting the motor, current measurement system, motor shaft angle sensor, vision systemand MYRIO which is an embedded hardware device created by National Instruments will be used for data acquisition and control the system

Recently, the high radiance of synchrotron sources was used to enhance FTIR spectrometer performance. However, excessive channel spectra when synchrotron sources are used degrade the quality of retrieved spectral parameters. In the research reported in this thesis, seven different techniques for handling channel spectra were investigated. These techniques were used to reduce channel spectra for a test group of seven samples of CO2 mixed with air recorded using the synchrotron source at the Canadian Light Source. The increases in signal to noise ratio (SNR) of spectra handled with each technique were calculated. SNR results showed that transmission spectra, produced using synthetic background spectra with simulated channel spectra, achieved the highest SNR improvement. However, when the spectra groups were fitted using nonlinear least square fit algorithm, the technique using channel spectra fitting produced the smallest fitting residual. Moreover, the retrieved intensities and air broadening coefficients of 21 spectral lines showed that the spectral fitting technique produced the most accurate values as compared to the HITRAN 2008 database. Although the spectral fitting technique was accurate in retrieving spectral line parameters, applying the technique at wider spectral ranges was less accurate. A modification to the channel spectra fitting technique by performing iterations of channel fitting was introduced to process wider spectral ranges. Carbon dioxide laser band I centred at 961 wavenumber was analyzed using 24 spectra recorded under different experimental conditions. The intensity and air-and self-broadening coefficients were retrieved for 48 spectral lines with average deviations from HITRAN database values of 2.11%, 1.25% and 4.14%, respectively, using the Voigt profile. These average deviations lie within the uncertainty limits listed by the database. The deviation between our results and other results reported in the literature were also examined and it is found to be also within the range of HITRAN uncertainties. The effect of errors in fitting channel spectra parameters was examined and found to be mitigated by the inclusion of channel-free spectra in the multispectral fit. / xiv, 134 leaves : ill. ; 29 cm