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Nowadays, electronics and mechanical devices are increasingly adapting the concept of self-stabilization. Similarly, as in the case of self-stabilization, self-stabilizing platforms have been utilized in numerous engineering disciplines. It is therefore necessary to examine how the Micro-electromechanical systems gyroscopes and accelerometer sensors are implemented in constructing functional self-stabilizing platforms. Various concepts were applied in the implementation of the project to achieve a phased set up of a DIY self-stabilizing platform. Some of these concepts include C++ programming, 3D printing, data analysis and deduction. The process also involved testing the hardware components. A theoretical understanding of the operation of the sensors and their limitations as well as analyzing ways to overcome them was also necessary. As result, a fully assembled DIY self-stabilizing platform that could successfully retain a balanced position with its balancing plate when an object was placed on it, was created. The platform can be further improved by use of bigger servo motors, as well as the use of smoother plastic enclosures other than the PLC 3D printed material.
This thesis was commissioned for Saimaa University of Applied Sciences with the aim of understanding the control system for a robotic arm. The Robotic Arm in this case was from Saimaa University of Applied Sciences. The main objective of this thesis was to understand a control system for the Robotic Arm using a programmable logic controller (PLC) along with gripper. The control system consisted of the electronic components (the PLC, a motor controller, a voltage regulator, a control pendent and a bride board circuit). The Robotic Arm works manually using potentiometers and also with the help of PLC. At the beginning, studies were carried out to define the design constraints for finding the best options among components that are most suitable for this application. A control system with a PLC needs additional electronic components, such as a DC motor controller and control pendant. The parts selected are those that met the specifications requirements. The majority of the time is spent on understanding wiring and installation. During the installation, consideration is made for a safe and effective process. In this work, for the design of the gripper, only the research and theoretical design approach is made. After the complete theoretical installation of all the hardware sections, the theoretical programming is the last to be completed. The principles for manual modes of operation and automatic modes of operation are described in detail in the programming part of this thesis. All the parts of the control system; i.e. the hardware part and the programming part are accomplished with a successful theoretical demonstration. The complex programming is possible in the PLC for the automatic mode of operation. It is found that a Robotic Arm with a simple mechanism can be manipulated in a different complex way by using a PLC.
This thesis aims to study different analytical methods to model a squirrel cage inductionmotor, which should have minimal simulation time than the corresponding finiteelement method (FEM) based models. The purpose of doing so is to develop a modelsuitable to simulate all major faults and be used for advanced model-dependent faultdiagnostic algorithms, such as parameters estimation and inverse problem theory. Thisthesis’s second key objective is to study various signal-processing techniques for theirpros and cons to detect fault at the embryonic stage and investigate the entire currentharmonic spectrum of induction motors both in transient and steady-state regions. Thus,the motor under healthy and broken rotor bar (BRB) conditions are simulated, andexperimental measurements are investigated for validation. The dynamic d-q model with the inclusion of non-linear magnetization inductance wasconsidered as a starting point. This model helps understand the machine's basic conceptsbecause of its comprehensiveness and ability to produce compact equations, which canbe used for drives as general and in observers and state estimators as particular.However, this model was found to be less suitable to simulate machine faults because ofthe considered approximations. To address the d-q model limitations, the winding function analysis (WFA) basedmodel was prepared. In this model, the analytical equations to calculate variousinductances, resistances, currents, fluxes, torque, and speed are derived for the motorunder investigation. These equations were simulated in MATLAB, giving results near tothe practical measurements. The model is suitable for implementing some faults, suchas BRB and broken end rings. Still, the consideration of constant air gap makes it lessideal for the implementation of eccentricity and saturation-related faults. Moreover, thespatial harmonics, which are very important for fault diagnostics and sensor-less speedestimation, cannot be simulated. Those approximations can be reduced with Fouriersummation of higher-order harmonics (winding) and Taylor series to include inverse airgap functions but at the cost of the self-defined number and amplitude of harmonics.To get more realistic results, the modified winding function analysis (MWFA) basedmodel was prepared to ensure that all winding functions and air gap were defined as afunction of stator and rotor individual and respective angles. The geometry of stator androtor slots is considered to calculate the leakage inductances and various resistances.The self and mutual inductances between rotor and stator are computed with a steppingrotor. The results at each rotor position are saved in offline 3D lookup tables. During theonline simulation, all pre-saved matrices are used as a rotor position function using theirindex value, and the performance parameters, such as currents, fluxes, torque, andspeed, are calculated. The FEM and hybrid FEM-analytical models of the machineunder investigation are prepared using commercial software to validate the results.The comparison of results shows an excellent agreement with a minimal simulation timeand least ill-posedness for the proposed model compared to the corresponding FEMmodel. Both analytical and hybrid FEM-analytical models are divided into online, offlineportions and compatible for the solution on cluster computation. Their division in the online and offline portions reduces the complexity and gives the model the freedom to simulate faults in the online portion without doing unnecessary offline calculations again.Moreover, the compatibility with cluster computation is excellent for exploitingdistributed computational resources such as cloud computation, an integral part ofindustry 4.0 standards. Towards the signal processing side, the fast Fourier transform (FFT) and wavelettransform (WT) are used extensively to study the steady-state and transient regimesignals. The infinite impulse response (IIR) based digital filters are used to improve themotor’s current spectrum’s legibility. In this way, the total harmonics are segregatedaccording to their cause of production. Moreover, the spectrum of current simulatedfrom the proposed model is compared with that simulated using the FEM model and thetest rig measurements. The comparison is made until a wide bandwidth of frequenciesfor further validation of the proposed model. Moreover, the WFA based model is also investigated during the transient regime bydoing the time-frequency analysis of the stator current. The recovered non-stationarysignal’s pattern is in good agreement with the one obtained from the practicalmeasurements. The specific fault-related pattern during the transient interval canfurther enhance the model’s effectiveness.
Various control strategies have been adopted for the field weakening control of the interior permanent magnet synchronous motors. Most of these either use the magnetic model parameters or utilize the approaches like the look up tables to minimize the effects of parametric sensitivity. The variation of the inductance values due to the magnetic saturation or the cross-coupling and fluctuation in the stator resistance and the permanent magnet flux due to the temperature difference can significantly affect the control performance especially at high speeds. In this thesis, the field weakening algorithm has been proposed that employs one of the model order reduction technique, i.e. orthogonal interpolation method. This technique obtained from reducing the order of the finite element model of the machine takes the stator current components as input and outputs the corresponding flux linkage components. At first, the control design was implemented utilizing the reduction technique that contained the motor parameters to test the validity of the orthogonal interpolation method in the field weakening operation. Thereupon, the technique was designed operating independent of any machine parameter that put into place the orthogonal interpolation method and its inversion for the references calculation. The simulink feature, ‘algebraic constraint’, was used in combination with the reduction technique to produce the required current components. The control techniques were implemented in the field oriented control scheme. The methods were at first tested through simulations in the MATLAB/Simulink environment and then the experiments were performed in the dSPACE laboratory for validity of the results. The results provided in the end confirm the feasibility of the approach used. The motor operates well in the field aweakening region and can operate in the wide speed range. The results also confirm that the approach operating independent of the machine parameters exhibit better control performance.
DC power supplies are being widely used in almost every modern day appliance. Basic DC power supply should only consist of AC/DC rectification unit with bulk capacitor. But irregular current drawn by rectifier pollutes the power system. Standards related to power quality puts a limit on harmonics that are being injected by a device into power system. To comply with standards Power factor correction (PFC) circuits are employed with rectification unit. Addition of an extra unit, puts a limit on overall efficiency of power supply. Advent of Wide Band Gap (WBG) power semiconductor devices have provided us with the opportunity to improve the efficiency of existing electronic circuits with relatively simple control schemes. According to recent research, it has been forecasted that GaN based devices are ideal choice for medium voltage and high speed applications. However, SiC based devices are estimated to take over high voltage applications. Conventional PFC circuit based on bridged CCM average current controlled Boost converter was chosen for this study. Simulation was made to compare the performance of GaN, SiC and Si based switches. Results from simulation revealed that 38% reduction in switching losses can be achieved by using GaN HEMT instead of Si MOSFET. Practical evaluation was performed on Transphom Totem Pole PFC and All in One Power supply. Both of these devices are based on GaN HEMTs. Totem pole PFC is the major breakthrough achieved by GaN HEMT in the field of PFC circuit. Very low reverse recovery of switches made it possible to implement this circuit with very high efficiency for high power applications. 94% efficiency was observed during evaluation of DC power supply, which validates the claim of superior performance of WBG devices.
Today’s internet was founded as a host centric abstraction for connecting machines over a geographically distributed data base. Since then it has exploded into a trillion dollar industry for providing services and content to the world. For meeting these ever growing consumer demands, internet service providers have used bolt-on approaches to patch the internet. On the other hand, the last decade has witnessed the worst natural disasters on earth which resulted in total or partial destruction of communication infrastructure. Understanding these challenges, researchers are committed to re-architect the internet with clean slate information centric approaches. These future internet architectures have shifted the dynamics from predominately location oriented models to data oriented models. These models provide location independence which eases the network configuration and implementation of network services in mobile environments. In this perspective, this thesis aims to hack content centric abstraction to provide optimized solutions for delay tolerant network scenarios. We provide information aware mechanisms which help to take adequate forwarding and caching decisions in these dynamic and challenged environments. This thesis proposes a unique popularity estimation algorithm and a name based prioritization algorithm for disseminating data more productively in intermittently connected networks. For evaluation it analyses the performance for both mechanisms and compare them with the latest solutions. Furthermore the thesis discusses potential research areas in the field of information centric networking and future directions for this thesis.
Wireless body area network(WBAN) is developed from personal area network that helps different sensors to communicate while being worn on human body. The passive UHF (Ultra-high frequency) RFID (Radio frequency identification technology) is one of the fundamental technology used for tracking animals, people and objects. Currently, an emerging area of development is the use of wearable RFID tags in health care systems. The personal healthcare systems demand information about sensed or measured biological parameters to be reliable and rapidly sent over a wireless communication link for investigation purposes. Furthermore, the communication system must be absolutely flexible, low-power, maintenance-free and low-cost in order to be utilized on different parts of the patient’s body for continuous monitoring of physiological parameters such as blood pressure, body temperature, glucose level, and respiration system. Therefore, due to the extensive need for the implementation on flexible and conformal material, researchers have been working on textile based RFID tags. One of the hottest topics is the development of electro-textile based RFID tags for body area networks. In this thesis, to measure the performance of wearable split ring antennas on electro-textile material, different split ring antennas have been developed that are materialized with two different kinds of materials such as copper and electro-textile. The development of wearable antenna is quite challenging task due to antenna material properties, environmental issues and radiation absorbing nature of human body at higher frequencies. By considering these factors, 85% antenna-IC power transfer efficiency at 915MHz has been achieved in body-worn configuration. Furthermore, to analyze the near body performance of developed antenna, distance between antenna and the human body has been varied, for example 2 mm, 3mm, 5mm and air. Moreover, to measure the performance of antenna on clothes, EPDM (Ethylene-Propylene-Diene-Monomer) substrate of different thicknesses i.e 2mm and 5mm have been used. From the simulated and measured results, it has been noticed that copper based split ring UHF RFID tag shows excellent match between measured and simulated results in body-worn configuration. Furthermore, provides excellent tag performance at variable antenna-body separations down to two millimeters and also in the air. Interestingly, this is novel feature of wearable antennas based on a single conductor layer. On the other hand, it has been analyzed that electro-textile based split ring RFID tag shows some variation between simulated and measured on-body/off-body results.
Mobile Operators are looking for new ways to cope with ever-increasing data traffic while improving the operational and capital efficiency of their networks. Cloud computing and network function virtualization (NFV) have emerged as key enablers to optimize resource utilization and at the same time reduce network operational expenditure (OPEX). In virtualized networks, network functions are delivered as software running on generic hardware allowing service providers to dynamically allocate resources based on traffic and service demands. This work presents resource utilization using real-life data of two different mobile networks and evaluate the impact virtualization would have on these networks. Dynamic scaling of resources in NFV is a highly important challenge towards its implementation in real-life networks. In this work, a method to predict the required resources in the appropriate time to sustain true elasticity in NFV is presented. The capacity of different Virtualized Network Functions (VNFs) would increase/decrease in a way that the CPU utilization is maximized while the overall cost is minimized. Two strategies to predict the day-ahead CPU utilization are presented. The first strategy is an offline scheduling method that helps managing elasticity in virtualized networks by predicting normal days events. The second one is an online scheduling approach that predicts the day-ahead CPU utilization during sudden peaks due to some unusual circumstances. This work also presents new promising results that show the correlation between the control and data planes. Finally, a hybrid algorithm is proposed that uses both strategies to efficiently handle elasticity in virtualized networks. The obtained results are encouraging and are all based on real-life data of mobile operator networks.
Security and usability are considered to be mutually antagonistic goals. Conflicts arise when recommendations from security and usability perspectives contradict each other. Academic research and industrial practices have revealed that conflict management mainly relies on the skill of the developers. Expertise in both security and usability is difficult to find in one person; therefore, there is a need to support developers when they attempt to manage conflicts. This research investigates the gaps in research and industrial practices concerning the alignment between security and usability. More importantly, this research investigates how conflicts can be effectively managed during the system development lifecycle. This research proposes the use of design patterns to support the developers in management of the conflicts. Besides other information each pattern encapsulates problem statement, suitable trade-off (the solution), and context of use. The work performed during this dissertation led to the creation of different artefacts that enable identification and documentation of design patterns. Each identified artefact has a context in which it can be applied for identification of design patterns. This research was conducted based on the principles of design science research. The identified artefacts are listed and discussed in the body of this dissertation. Moreover, various data collection methods, including surveys, interviews, and workshops, were utilised to rationalise and validate this research when applicable. This research contributes to alignment between security and usability in the system development lifecycle. The key findings are as follows: (1) security and usability can be synergised by managing their conflicts during the system development lifecycle as early as possible; (2) the conflicts can be better understood at the level of the sub-characteristics of security and usability; and (3) the artefacts (formulated during this research) can be helpful for developing a catalogue of usable security design patterns, and the patterns can be used to influence the decision-making of developers and designers in similar contexts.
Arabidopsis thaliana, lituruoho, toimii kasvikunnan malliorganismina muun muassa forosynteesireaktioiden tutkimisessa. Fotosynteesireaktioissa vihreät kasvit tuottavat kloroplasteissaan vedestä ja hiilidioksidista auringon energian avulla happea ja sokeria. FNR (Ferredoksiini-NADP+-oksidoreduktaasi-entsyymi) osallistuu fotosynteesissä elektronin-siirtoreaktioihin pelkistämällä NADP+:n NADPH-molekyyliksi, jota käytetään ATP:n kanssa hiilensidontareaktioissa. Lituruohon genomissa kaksi eri geeniä At5g66190 (FNR1) ja At1g20020 (FNR2) koodaavat kloroplastiin ohjautuvia FNR-isoentsyymejä. Molempia isoentsyymejä esiintyy villityypin kasveilla kloroplastissa sekä liukoisessa muodossa että kiinnittyneinä tylakoidikalvoon. fnr1-poistogeenisellä kasveilla FNR1-geeni on keskeytetty, jonka seurauksena FNR1-proteiinia ei tuoteta mutta FNR2-proteiinia esiintyy kloroplastin stroomassa. fnr2-poistogeeniset kasvit eivät tuota FNR2-proteiinia mutta FNR1-proteiinia esiintyy kloroplastin stroomassa ja tylakoidikalvoilla. Opinnäytetyön tarkoituksena on valmistaa FNR1 yliekspressiolinja fnr2-poistogeeniseen taustaan ja FNR2 yliekspressiolinja fnr1-poistogeeniseen taustaan. Yliekspressiolinjoissa tuotetaan ylimäärin kyseistä FNR-isoentsyymiä. Yliekspressiolinjoja tutkimalla pyritään selvittämään johtuuko mutanttikasvien fenotyyppi FNR:n alhaisesta totaalimäärästä vai ainoastaan toisen isoentsyymin puuttumisesta. Samalla kerätään lisätietoa fotosynteesi-mekanismeista. Yliekspressiolinjoja tuotetaan käyttämällä yhdistelmä-DNA-tekniikan menetelmiä. E. colin DH10B-linjan DKLAT5g66190- ja DKLAT1g20020-plasmideissa olevat FNR-geenit eristetään ja liitetään agrobakteerissa toimivaan pGWR8-plasmidiin. pGWR8-konstruktit transformoidaan agrobakteeriin, joka luonnostaan pystyy infektoimaan kasveja Ti-plasmidinsa avulla. Infektoituneet kasvit voidaan erottaa muista kasveista pGWR8-plasmidissa olevan antibioottiresistenssikasetin avulla kasvattamalla kasvin siemeniä selektiivisellä kasvatusalustalla. Vain mutatoituneet siemenet voivat kasvattaa alustalla juuria ja ne voidaan siten siirtää mullalle kasvamaan. Agrobakteerivälitteisen trasformaation tuloksena saadaan kaksi mutanttikasvia, yksi tuottaa ylimäärin FNR1- isoentsyymiä ja toinen FNR2-isoentsyymiä. Homotsygoottisia kasveja tutkitaan myöhemmin muun muassa proteiinitasolla immunoblottauksella.
Utilitarian thinking comes under the wider framework of normative ethical theories which judges the morality of any act based on the outcomes achieved. Normative Ethics is the discipline of social sciences that comes under the head of philosophy which is based on moral principles. Based on such moral principles, any act is being considered as either right or wrong. Like any other domain, cyberspace also has some ethical values. To understand the ethics on Cyberspace, first we need to understand that how internet works and how many layers it has and what kind of activities are possible over every layer, respectively. This thesis aims to explain the privacy issues caused by Panopticons related to illegal, unethical, and un-consensual mass surveillance across the internet via using various insidious methodologies. It also explains that who panopticons are and how this terminology came into existence and how it replicates current era’s mass surveillance? Moreover, it addresses the parameters under which any surveilling authority could be declared as a Panopticon. It explains that how and why Panopticons are doing unauthorized, unethical and non-consensual mass surveillance and how that surveillance actually takes place and up to which extent Panopticons have gone to achieve their desired mode of surveillance and it highlights different actors that are involved in mass surveillance at different scales via different techniques. The involvement of Governments with or without the collaboration of Private Internet companies has also been a shady topic exactly till Snowden made his revelations which later on caused a drastic awareness among masses and opened new doors of discussion as well as urged authorities to take some practical measures in order to curb the mass surveillance. That is why, Snowden’s revelations have been taken as a case study to present the depth and techniques of mass surveillance that are in practice both by private and government organizations. The analysis part holds the primary importance in this thesis, that’s why the thesis concludes with analyzing ethical aspects of Mass Surveillance via Utilitarian point of view which analyzes the Snowden’s act of reveling classified information and the corresponding top three accusations posed on him by USA’s house of representatives, followed by legal and cultural implications.
Security and usability are two important characteristics often in conflict with each other. This paper presents challenges related to alignment between security and usability in the industry. The challenges were identified after analyzing the data from 12 semi-structured interviews. There were nine different challenges in industrial practices which were identified after the interviews, moreover, two recommendations for future solutions were also identified. The paper also presents a framework for addressing the identified challenges within the industry context. The framework presented in the paper has been tailored for the agile development context and aims at identifying minimal trade-offs between security and usability.