DSpace Repository :: Browsing 02. Master's Thesis by Issue Date

02. Master's Thesis

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PERFORMANCE EVALUATION OF HYBRID VLC/RF SYSTEMS
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Ashimbayeva, Aigerim
The thesis is dedicated to analysis and comparison between hard switching and soft switching methods for hybrid VLC/RF systems. VLC communication is well known for its efficient high data rate service for use in indoor environment, however it is vulnerable to the line-of-sight obstruction. Its counterpart, RF communication, is easy to implement and efficient as a back up means. Optimization of the VLC/RF heterogeneous systems in terms of the overall throughput is the novelty in the field of related studies on VLC technology based hybrid systems. It allows not only to improve the system’s bit rate but also to find the most favorable initial parameters for a system. The results of simulations performed reveal the remarkable superiority of the soft switching scheme and VLC-RF throughput functions interrelationship.
Open Access
FEASIBILITY STUDY ON WIND ENERGY HARVESTING SYSTEM IMPLEMENTATION IN MOVING TRAINS
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Nurmanova, Venera
Feasibility study on implementing wind power generation on moving train is discussed in this Thesis. Wind turbines installation over the train roof is suggested and tested from different aspects. Practical aspects of wind energy utilization are discussed and challenges are highlighted. Calculations of wind power generation for wagon roof mounted turbine are provided and air drag of turbine is discussed. Simulation study is performed in SolidWorks environment to explore air drag influence of wind turbines on moving train. Simulation of wind power generation is also conducted in MATLAB Simulink. Analytically the generated power is compared to mechanical power required to overcome the extra air drag caused by wind turbines over the train wagons. Economical profit of the suggested design is also discussed in detail. The fuel economy and resultant decrease of the carbon dioxide emission have shown the reasonableness of investments on wind turbine implementation on the passenger trains. The payback period calculations for different scenarios are also discussed at the end.
Open Access
LTE IN UNLICENSED BANDS: A RIVAL OR COLLABORATOR TO WI-FI?
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Karabayev, Omar-Sayan
Due to the rapidly increasing demand for internet traffic, mobile operators have faced a problem of bandwidth availability. Since only licensed spectrum has been previously utilized by wireless networks, moving LTE to the 5 GHz unlicensed bands has become a popular research initiative, known as LTELicensed Assisted Access (LTE-LAA). This thesis studies the feasibility and implementation of LTE-LAA, and sets a goal of confirming the effectiveness of this technology. An alternative implementation of a Listen-Before-Talk channel contention mechanism is tested in this work with the use of LTE-A Vienna Link Level Simulator. The obtained results suggest that LTE-LAA is capable of boosting network throughput while providing harmonious coexistence with the IEEE 802.11 standard operating in the same unlicensed spectrum.
Open Access
MOVING OBJECT DETECTION WITH MEMRISTIVE CROSSBAR ARRAYS
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Duisenbay, Sultan
This thesis is dedicated to the hardware implementation of a novel moving object detection algorithm. Proposed circuit includes several stages, each of which implements a particular step of the algorithm. Four higher bit planes are extracted from a grayscale image and stored in memristive crossbar arrays, and the respective bit planes are compared via memristive threshold logic gates in XOR configuration. In the next stage, compared bit planes are combined by weighted summation, with a highest weight assigned to MSB plane and smaller weights for less significant bit planes. After summation stage, obtained grayscale image is thresholded to obtain binary image. The last stage is implemented via memristive content-addressable memory array, which serves two purposes. It is used as a long-term memory in comparison to crossbar arrays, which serve as a short-term memory of proposed circuit. Content-addressable memory is updated based on the row-by-row difference between first and second pair of frames processed by previous stages. It also allows for analysis of object movement direction and velocity by observing the row capacitors’ discharge. Simulations show that accuracy of proposed circuit operation is increased with the larger array size. Delay analysis of the circuit is carried out, power and area calculations show that proposed circuit is a viable candidate as a co-processing operator for existing image sensors.
Open Access
MOVING OBJECT DETECTION USING BIT PLANE SLICING
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Dastanova, Nazgul
This thesis presents moving object detection algorithm using bit plane extraction of successive frames and comparing the respective bit planes by XOR operation. The proposed methodworks on 8-bit grayscale video frames obtained from a static camera. This algorithm is able to detect the motion of single and multiple objects in outside and inside environments. Algorithm has been implemented in MATLAB by using several videos from VISOR database and was compared to existing conventional methods to show its effectiveness. Performance of an algorithm was evaluated based on ground truth metrics and results in terms of sensitivity, specificity, positive prediction and accuracy proved the validity of it. Results show that the proposed algorithm performs better in terms of mentioned metrics in comparison to other algorithms. i
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EXPERIMENTAL INVESTIGATION OF VLC SYSTEMS WITH CAMERA RECEIVER
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Bekkaliyev, Talgat
Current fluorescent and incandescent lamps are being replaced by solid state Light Emitting Diodes (LEDs), which offers much higher energy efficiency and longer lifespan. Apart from that LEDs are able to switch on and off at rapid rates. Such capability has given a lift to new communication technology – Visible Light Communication (VLC). LED serves as a transmitter, by providing high throughput data transfer, while photodiode or optical camera are utilized as a receiver. This thesis experimentally investigates a VLC system that uses a camera receiver. We first analyze the system with simple On-Off Keying (OOK) technique and further propose an alternative technique – Pulse Amplitude Modulation (PAM), which increases the data rate and avoids visible flickering. Furthermore, this thesis investigates VLC exploiting rolling shutter mechanism of CMOS images sensors with OOK. The Bit Error Rate (BER) performance and some characteristics of systems are presented. Next, VLC utilizing rolling shutter mechanism with Color-Shift Keying (CSK) is developed. Such a system achieved substantially higher data rates compared to VLC exploiting rolling shutter mechanism with OOK.
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FEASIBILITY STUDY ON SOLAR ENERGY HARVESTING SYSTEM IMPLEMENTATION ON MOVING TRAINS
(Nazarbayev University School of Engineering and Digital Sciences, 2016) Kudaibergenov, Zhaksylyk
This Thesis is concentrated on feasibility of solar energy harvesting system implementation on top of the moving train. Following study consists of two different ways of solar energy generation. Firstly, solar system consisting of solar panels with supplementary equipments (the charge controllers, batteries, inverters) is fitted to the roof of train coaches to supply its internal energy requirement, and secondly, solar system is implemented over the shelter of platform in train stations to feed the railway grid. Then solar-powered train travels on two specific key routes from south to the north and from south to the west of Kazakhstan are simulated and studied in detail. Above described method has practical challenges in facing variable air temperature, solar radiation and sunshine hours. This data is obtained from the NASA database, and the variable parameters for each station are calculated in MATLAB. Afterwards, the entire solar system is simulated in MATLAB Simulink and the total required investment is calculated including costs of all equipments. The return investment time is calculated according to the power generated from solar system and saved money from fuel economy. Moreover, solar-powered train shows the significant cut of carbon dioxide emission because of the fuel iii economy. Both of the payback time and decreasing of CO2 emission reveal the benefits of investment.
Open Access
TIME DOMAIN EVALUATION OF MULTILEVEL CONVERTERS VOLTAGE AND CURRENT QUALITY
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12) Urtanbayev, Nurlan
Multilevel converters are power conversion devices consisting of voltage sources and semiconductor switches. This work was motivated by the fact that majority of the conducted research estimates converter quality using frequency-domain approach, which is requires tones of calculation. As an alternative for frequency-domain approach, time-domain evaluation method, developed in a recent time, was selected. This method brings novelty in deep-seated method of convertor evaluation, based on frequency-domain. General goal of this thesis is to demonstrate competency and applicability of time-domain optimization method on online adaptive inverter systems. Work will be focused on development of algorithm for calculation of optimal parameters for single phase CHB converter. Modulation optimization and local minimum finding algorithms are developed and discussed in this work. Moreover, combination of SHE and THD minimization techniques was designed and simulated. Obtained results coincide with those presented so far. However, majority of the results are novel, and has not presented to community yet. Future work will focus on development of the optimization algorithm for three-phase inverters.
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Life Cycle Analysis for Wind Turbines and/or other Electricity Generation Technologies from Renewable Sources
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12) Almakhan, Mukhammed; Kostas, Konstantinos; Rojas-Solórzano, Luis
In recent years, there have been increasing advances in the field of wind farms. A growing interest for wind farms brings, at the same time concerns about potential impacts on the environment. An extensive study has been conducted to contribute to the existing knowledge about influences of wind energy systems on the environment. The study involves the following stages: to measure the environmental impact of a single Vesta NM82 wind turbine, including all stages from raw material extraction to the end of life stage; in the next stage, the emissions resulting from electricity generation by wind energy extraction and coal use and combustion are compared. This study also demonstrates the potential of wind energy production sector and the necessity in development of energy production from renewable sources. In addition, this study demonstrates the importance of material recycling, which alleviates some of the negative impacts to the environment. During the research, it was realized that wind turbines, combined with additional energy sources, have significantly lower impact to the environment in comparison with coal energy. Furthermore, proper selection of materials is found to be one of the most important issues that one should take into account
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Process Modelling of Biogas Utilization System for the Landfill in Astana
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12) Myrzagaliyev, Azat; Amouei Torkmahalleh, Dr.Mehdi; Rojas-Solorzano, Dr.Luis
This thesis provides estimates of energy potential of biogas produced from a landfill in Astana in the form of electricity, as well as the economic assessment of the proposed power plant design. The goals were accomplished by first assuring a sufficient amount of landfill gas production rate. Then, a field work was carried to determine the precise biogas content. Theoretical calculations were done using the empirical equations recommended by the US Environmental Protection Agency (EPA). The energy model was simulated on ASPEN Plus. To reduce the concentration of corrosive hydrogen sulfide (H2S) in the gas, a model of a water scrubbing system was simulated in this work. Further, to obtain a maximum rate of power production, the upgraded biogas was utilized in a combined cycle gas turbine (CCGT) unit. By adding the Rankine cycle to the Brayton cycle to build up the combined system, the efficiency of the system increased from 35% to 49%, with 5 MWh power output. After obtaining the results of the energy model, the economic viability of the project was evaluated. The analysis showed that with right investment terms, the project is highly profitable. With equity payback period of 2 years, the NPV of the project was above 6.5 billion KZT, and annual life cycle savings around 1 billion KZT.
Open Access
NATURAL VOLTAGE BALANCING IN HYBRID FCC MULTILEVEL CONVERTER
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12) Kunakbayev, Aslzhan
Multilevel converters are frequently used in high and medium power applications. The challenge associated with successful operation of multilevel converters, is the voltage balancing. There are two major techniques dedicated to deal with the voltage balancing, namely: natural and active voltage balancing techniques. Natural balancing is more preferable, since it does not require sensing and in-time controlling equipment. Accepted methods of natural balancing investigation is based on the manipulations of the frequency components. This methods imply heavy computations and not general solutions. In contrast, time-domain analysis, proposed in this paper, produces simple closed-form solutions and requires simple mathematical calculations. The project is focused on performing time-domain analysis in order to investigate natural balancing characteristics of Combined H-Bridge Flying Capacitor Converter (HFCC) converter, for which natural balancing investigations is not reported in literature yet. Modulation strategy was obtained using Matlab software simulation and were implemented with PWM control and Matlab Simulink interface. Obtained results have demonstrated the fast balancing rates with natural balancing, for the majority part of modulation range. In addition, produced analytical equations, that describe voltage balancing dynamics do not require heavy computational effort and could be calculated online.
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Regional energy system modeling with alternative energy sources in Kazakhstan
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12) Kazmaganbetova, Meruyert; Luis R. Rojas-Solórzano, Aiymgul Kerimray
Kazakhstan is emerged as a result of Soviet Union dissolution and it has 9th largest territory in the world. Despite its large territory Kazakhstan has low population density. Kazakhstan is rich of fossil fuels, particularly oil, coal and gas. Its economy is highly carbon intensive and coal plays an important role in electricity production, accounting for 75 % of electricity produced. Due to poor quality coal, low energy efficiency and high energy intensity Kazakhstan’s emissions are amongst highest in the world. Such an environmental issue challenged Kazakhstan to diversify the economy and take measures such as improving the efficiency of power plants, reducing the sectoral energy intensity and adoption of renewable energy sources. Kazakhstan has huge amount of renewable and non-renewable energy sources. The total potential of renewable energy sources in Kazakhstan is much higher than the total installed capacity of power plants operating in Kazakhstan. Along with high renewable energy sources potential, Kazakhstan established feed-in tariffs for the electricity generated by renewable energy sources. However, it is necessary to achieve a balance between economic competitiveness and the need to respond to the threat of climate change. Thus, current research aims at modeling the implementation of subsidies for renewable energy sources on regional basis using tool TIMES and observing the effect of different levels of subsidies on the electricity production sector and emissions.
Open Access
SOFTWARE AND HARDWARE IMPLEMENTATION OF THE NEUROMORPHIC LGN BASED IMAGE PROCESSING AND FEATURE EXTRACTION
(Nazarbayev University School of Engineering and Digital Sciences, 2016-12-09) Dorzhigulov, Anuar
The processing of the graphical data is popular methodology of obtaining important information. However, there is a major drawback: it typically requires large computational resources. The human brain is an excellent example of the efficient image processing hardware, due to the fact the biological visual system can allow to easily and quickly obtain the information of the world around, such as object identification and movement detection. In particular, there is one element of the biological visual system that has unique functionality in image processing, which is lateral geniculate nucleus (LGN). Ganglion cells, which are terminated in LGN, have high sensitivity to the image spatial intensity difference. This cell feature is used for pre-processing of the visual data before being modulated and relayed to the main processing module, visual cortex. As a result, the processing load on cortex is reduced, due to the pre-processing of the data. The aim of the project is to develop the algorithm for visual features extraction, such as edge detection, based on the structure and properties similar to the LGN, with a possibility of the hardware model implementation. Preliminary results show the edge detection property of the proposed method. Moreover, the measured performance is comparable to other popular edge detection techniques, even exceeding expectations to small extent in the noisy environment.
Open Access
HIGH-DIMENSIONAL SIGNAL PROCESSING AND STATISTICAL LEARNING
(Nazarbayev University School of Engineering and Digital Sciences, 2017) Bakir, Daniyar
Classical statistical and signal processing techniques are not generally useful in situations wherein the dimensionality (p) of observations is comparable or exceeding the sample size (n). This is mainly due to the fact that the performance of these techniques is guaranteed through classical notion of statistical consistency, which is itself fashioned for situations wherein n >> p. Statistical consistency has been viogorously used in the past century to develop many signal processing and statistical learning techniques. However, in recent years, two sets of mathematical machineries have emerged that show the possibility of developing superior techniques suitable for analyzing high-dimensional observations, i.e., situations where p >> n. In this thesis, we refer to these techniques, which are grounded either in double asymptotic regimes or sparsity assumptions, as high-dimensional techniques. In this thesis, we examine and develop a set of high-dimensional techniques with applications in classification. The thesis is mainly divided to three parts. In the first part, we introduce a novel approach based on double asymptotics to estimate the regularization parameter used in a well-known technique known as RLDA classifier. We examine the robustness of the developed approach to Gaussianity, an assumption used in developing the core estimator. The performance of the technique in terms of accuracy and efficiency is verified against other popular methods such as cross-validation. In the second part of the thesis, the performance of the newly developed RLDA and several other classifiers are compared in situations where p is comparable or exceeding n. While in the first two parts of the thesis, we focus more on double asympii totic methods, in the third part, we study two important class of techniques based on sparsity assumption. One of these techniques known as LASSO has gained much attention in recent years within the statistical community, while the second one, known as compressed sensing, has become very popular in signal processing literature. Although both of these techniques use sparsity assumptions as well as L1 minimization, the objective functions and constrains they are constructed on are different. In the third part of the thesis, we demonstrate the application of both techniques in high-dimensional classification and compare them in terms of shrinkage rate and classification accuracy
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REAL TIME PREDICTIVE CONTROL OF UR5 ROBOTIC ARM THROUGH HUMAN UPPER LIMB MOTION TRACKING
(Nazarbayev University School of Engineering and Digital Sciences, 2017) Omarali, Bukeikhan
This thesis reports the authors’ results on developing a real-time predictive control system for an Universal Robot UR5 robotic arm through human motion capture with a visualization environment built in the Blender Game Engine. The UR5 is a 6 degree of freedom serial manipulator commonly used in academia and light industry. It is a very safe robot by design that comes at a cost of a rather limited API with very little support of real-time operation. The motion tracking is performed by a wireless low-cost inertial motion capture setup produced in-house. The motion tracker is an extension of author’s previous work on replacing a forearm IMU in conventional inertial motion tracking suits with a potentiometer in order remove anatomical constraints from corresponding data fusion algorithms. The external controller incorporates an iTaSC SDLS IK solver and a Python wrapped C explicit model predictive controller generated using the Multi Parametric Toolbox. The visualisation provides the user with the feedback on the robot’s progress towards the target. It is planned to extend the visualisation to virtual reality in future. Tests have shown that the robot follows the operator’s wrist position and orientation with an average of 0.05sec. time lag in the case when the operator moves under the robot’s velocity and acceleration limits. When the operator moves too fast for the robot to keep up in real-time, the robot is able to catch up with the operator with little or no overshooting. Thesis results are described in a late-breaking report and demo accepted by the 12th annual IEEE/ACM international conference Human-Robot Interaction (HRI2017).
Open Access
IDENTIFYING AND REMOVING BARRIERS TO INNOVATION IN BI GROUP
(Nazarbayev University School of Engineering and Digital Sciences, 2017) Akhmetova, Ainur; Khassenova, Assiya
To succeed in today’s fast changing world, companies specifically operating in a high knowledge-intensive industries must continuously innovate and improve. In this regard, firms worldwide are quickly raising their awareness of the significance of the role of knowledge management (KM) in the innovation process. Many successful companies have already achieved excellent results in the KM implementation, and thus have learnt how to bring innovation to their organizations. However, there is no universal approach to KM, and obviously any company first has to start with the exploring the obstacles to innovation.
Open Access
T-MESHES AND T-SPLINE MODELLING FOR FREE-FORM SHAPE REPRESENTATIONS AND ISOGEOMETRIC ANALYSIS
(Nazarbayev University School of Engineering and Digital Sciences, 2017-01) Faiznur, Alibek; Kostas, Konstantinos; Rojas-Solórzano, Luis R.
Nowadays, Isogeometric Analysis has become an effective alternative to traditional Design to Analysis process which uses the same geometry standard both for Design and Analysis purposes. However, NURBS, currently used in Isogeometric Analysis standard, has the limitation of rectangular topology, which results in many superfluous control points. Such points increase the computation time of simulation processes. Moreover, complex object models are composed of a number of NURBS patches, and thus, the designer has to spend time to revise the connectivity between the surfaces. Recently, T-splines surface was explored to overcome the limitations of NURBS. This paper provides the analysis of T-spline implementation in Isogeometric Analysis. It starts from mathematical definition of NUBRS and T-splines, then it describes implementation of T-splines in Rhino and provides the developed program which defines T-mesh parameters.
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PARAMETRIC MODELING FOR SHAPE OPTIMIZATION
(Nazarbayev University School of Engineering and Digital Sciences, 2017-01) Bocharov, Sergey; Kostas, Konstantinos; Rojas-Solórzano, Luis R.
Shape optimization has become a necessity in our pursuit for performance and efficiency in highly competitive fields ranging from engineering and science and finishing to medicine and agriculture. This plethora of shape-related problems gives rise to the requirement of flexible and generic frameworks that can address a wide series of problems. In our work, we closely examine the development of such a framework for the case of fluid flows around airfoils but we implement it in a way that would allow the extension of our approach to different areas of application. Commercial software packages like Solidworks or Ansys offer an advanced modeling and analysis environment but they do not come up with the required flexibility and customization capability demanded in our endeavor. On the other hand, the open source software package like OpenFOAM coupled with Matlab proved to be an efficient combination for our purposes. As a benchmark case for the framework, airfoil shapes are optimized at a single-point operating condition with fixed flow parameters. The Matlab's implementations for constrained nonlinear optimization drive the shape optimization process in our framework. The parametric model is based on the NURBS curve representation and the resulting airfoil instances are generated with the aid of eight parameters. Airfoil's performance is evaluated via appropriate flow analysis solvers for the selected range of applications. The framework's capabilities are demonstrated in the optimization of a given airfoil 6 shape with respect to its lift coefficient. Specifically, a 4% increase is attained for the lift coefficient while the shape parameters are constrained to deviate up to 0.5% from the initial values.
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KINEMATIC AND KINETOSTATIC ANALYSIS OF A THREE-FINGER UNDERACTUATED PROSTHETIC HAND
(Nazarbayev University School of Engineering and Digital Sciences, 2017-01-01) Mukhanov, Nurzhan
Mankind has long been looking for opportunities to return the deficient parts of bodies for people with disabilities. This is especially applicable to the loss or congenital absence of arm, which requires a functional and light prosthesis to improve the quality of a person’s life. However, it is rarely possible to combine these two features in the prosthesis without compromising one of them. Improvement in one of these parameters leads to a deterioration of another: it usually becomes necessary to choose between functionality and the weight. Thus, the question arises about the possibility of creating a prosthesis that is both functional and lightweight. To create highly functional, light prosthesis with subsequently optimized design, and less weak areas, it is necessary to establish a more detailed understanding of the system, to recreate the model of the movement and to understand the kinematics and kinetostatics of the prosthesis. To address this issue, the use of four-bar linkage system in prosthesis will be presented in this thesis. Also, the thesis will discuss the reasons why this model of prosthesis was chosen, the principle of work of the four-bar linkage system in the prosthetic finger mechanism, and provide its kinematic and kinetostatic analysis.
Open Access
Treatment of toxic wastewater by use of biological processes
(Nazarbayev University School of Engineering and Digital Sciences, 2017-12) Doskaliyev, Daniyar
The present work evaluates the capacity of suspended-growth un-acclimated sludge in treating 2-chorophenol (2-CP) and 2,4,6 – trichlorophenol (2,4,6 – TCP) containing synthetic wastewater in Continuous Flow Reactor (CFR) and in Sequencing Batch Reactor (SBR). In CFR, 2-CP concentrations were 103 and 163 ppm; 2,4,6 – TCP concentrations were 71 and 72 ppm. Under these 2-CP and 2,4,6 –TCP loadings, TSS growth was halted. Also, continuous decrease in nitrification was observed characterized by increasing effluent ammonium and decreasing nitrate production. 2-CP and 2,4,6 – TCP removals were decreasing under all their concentrations. In SBR, 2-CP inlet concentrations were 17 and 51 ppm; 2,4,6 – TCP inlet concentrations were 20 and 26 ppm. TSS demonstrated continued growth under all chlorophenol concentrations. 2-CP 17 and 51 ppm inhibited nitrification process. 2,4,6 – TCP 20 and 26 ppm did not cause nitrification inhibition. 100% removal of all 2-CP and 2,4,6 – TCP feed concentrations was achieved. Aeration in SBR played a significant role removing 43.9 % of Total Carbon (TC) and 39.9% of Total Nitrogen during the 1st day of experiment.