A market for a low-cost vibration protection device in the rotating machine industry has been identified that satisfies the needs of small firms unable to afford and sustain a condition monitoring operation. In this project, a system is developed that satisfies the need for a low-cost, conservative, configurable and intuitive device that can perform vibration measurements on a range of gearboxes and make an inference as to the level of vibrations coming from the bearings on the shafts. The inference made by the device, derived from the frequency content of the measured signal, may be used by the operator of the gearbox to make a judgment of whether to have the gearbox investigated by a competent authority. In order to assist this investigation, a vibration history of the device is stored, both in time and frequency domain formats, as well as a full history of the relevant diagnostic information. To reach this point of maturity, the project evolved through three different hardware configurations. The various iterations were tested within the scope for which they were designed and the lessons learned after each test was incorporated into the next iteration. The final iteration incorporated all the refinements of the system up to that point as well as the anticipated scope of further development into the commercial realm. To verify the inference credibility of the device, the results of the final specification of the device was evaluated against data obtained from the condition monitoring department of SASOL in Secunda. The results were analysed on two accounts. Firstly the signal reproduction accuracy was evaluated, which established how accurately the signal was digitized and how the processing algorithms performed. Secondly, the inference accuracy was gauged against the practices of SASOL. On both accounts, the final device performed satisfactorily. The end result of this project is considered a ‘near-commercial ready’ prototype with all the hardware on-board for user interaction, signal processing, 3rd party viewing of the data and future expandability. / Dissertation (MEng)--University of Pretoria, 2014. / tm2015 / Mechanical and Aeronautical Engineering / MEng / Unrestricted

The study explored teacher educators’ utilization of constructivist education practices to develop ESL in a teacher training institution and student teachers’ engagement in the instructional practices. In light of Chomsky’s proposition in his Universal Grammar (UG) (Cook & Newson 2007) all humanity, under normal conditions, is wired with a language acquisition device (LAD), which is activated in any real-life context when individuals experience exposure to any language. In the formal learning context; teacher education in particular, student teachers experience academic language which presents challenges, resulting in poor academic performance. Cummins (2009) proposes context embedded communication to afford acquisition of academic language. This learning environment is supported for pedagogy in constructivist learning settings, thus constructivist theories of learning provided the study’s theoretical framework. This was a qualitative case study utilising lesson observations of a class of 150 first year student teachers and 4 of their teacher educators. The 4 educators and 5 of the student teachers also attended to open-ended survey questionnaires, semi-structured interviews, including reflective journals for the latter. Data were analysed through a discourse analysis approach to determine educators’ education practices and student teachers’ meta-learning actions. Findings indicated that student teachers could identify their ESL incompetence but rated it incorrectly. An overarching ESL challenge was with the writing mode. Teacher educators utilised student teachers’ real-life experiences but partially immersed them in independent exploration of tasks to foster meta-learning actions and acquire disciplinary discourses, thus the students relied heavily on their educators’ assistance than independent learning. / Thesis (PhD)--University of Pretoria, 2017. / Humanities Education / PhD / Unrestricted

The purpose of this project was to investigate if it is possible to have local wireless control of an industrial robot. This was achieved by first doing a diversity of research. Based on the research, the project was conceptualized and a real-life product was developed showcasing the functionality. The standard robot set up as of today consists of three main parts: A robot, a control unit and a handheld controller device, called Teach Pendant. All of these parts are connected with long aggravating cables. The cables cause inconvenience and can in some cases introduce unnecessary risks in the factory. Can this hardware be removed, and an overall more convenient use case be developed? The product was developed by programming an application on a Windows tablet. Further, a Bluetooth Low Energy server was created to handle the communication between the tablet and the robot control unit. The final product consisted of a tablet, a single-board computer, a robot and a control unit. The tablet is what replaces the Teach Pendant as a handheld device. The tablet is connected to the singleboard computer via Bluetooth. The single-board computer acts as a Bluetooth server and sends out advertisements for the tablet to detect. When the tablet detects a nearby robot it can then connect to it and send start and stop commands. The server then forwards it to the control unit which finally sends the data to the robot control unit to execute. The project shows that it is possible to develop wireless robot control. It showcases a potential solution on how one could set it up. However, the final product developed had a simple functionality compared to the wired Teach Pendant. To manage the same capacity as the wired Teach Pendent, further development is required.

To set up port forwarding rules on network gateways, certain technical skills are requiredfrom end-users. These assumptions in the gateway software stack, can lead to an increasein support calls to network operators and resellers of customer premises equipment. Theuser interface itself is also an important part of the product and a complicated interfacewill contribute to a lessened user experience. Other issues with an overwhelming userinterface include the risk of faulty configuration by the user, potentially leaving the networkvulnerable to attacks.We present an enhancement of the current port forwarding configuration in the gatewaysoftware, with an extensible library of presets along with usability improvements. To helpusers with detecting available services, a wrapper for a network scanner is implemented, fordetecting devices and services on the local network. These parts combined relieves end-usersof looking up forwarding rules for ports and protocols to configure their gateway, basingtheir decisions on data collected by the network scanner or by using an applications nameinstead of looking up its ports. Another usability improvement is an internal DNS service,which enables access to the gateway interface through a human-memorable domain name,instead of using the LAN IP address.Using the Nmap utility for identifying services on the network, could be consideredharmful activity by network admins and intrusion detection systems. The preset libraryis extensible and generic enough to be included in the default software suite shipping withthe network equipment. Working within the unified configuration system of OpenWrt, thepreset design will add value and allow resellers to easily customize it to their services. Thisproposal could reduce support costs for the service operators and improve user experiencein configuring network gateways. / Vid portmappning i nätverksgateways krävs det vissa tekniska förkunskaper av användaren.Höga krav på kunskapsnivå kan leda till ett ökat antal supportsamtal för återförsäljareoch nätverksoperatörer. Användargränssnittet i sig är också en viktig del i produkten ochett komplicerat gränssnitt bidrar till försämrad användarupplevelse. Övriga problem medkomplicerade användargränssnitt är risken för felaktig konfiguration, vilket kan försämraIT-säkerheten på nätverket.En förändring av nuvarande inställningar för portmappning presenteras, tillsammansmed ett utbyggbart bibliotek med förinställda regler, samt generella förbättringar av an-vändargränssnittet. Ytterligare förbättringar av användarvänligheten sker i form av nä-tadressöversättning, som möjliggör åtkomst till nätverksgateway via domännamn som ärenklare att minnas än IP adressens siffror. För att hjälpa användare med identifikationav enheter och att göra rätt inställningar, utvecklas en wrapper för en portskanner, somautomatiskt kan identifiera enheter och nättjänster på det lokala nätverket. Tillsammansunderlättar dessa delar för slutanvändaren, befriar den från att referera till regler för portaroch protokoll och möjliggör inställningar enbart genom att använda portskanning eller väljanamnet på önskad tjänst från en lista.Användandet av verktyget Nmap för att identifiera nättjänster på nätverket kan kommaatt betraktas som dataintrång av nätverksadministratörer och intrångdetekteringssystem.Konfigurationsfilerna med förinställningar är utbyggbar, fungerar och passar in tillräck-ligt bra för att levereras med standardmjukvaran. Via det centraliserade konfigurationssys-temet i OpenWrt, kommer utformningen av systemet med förinställningar för portmappningmöjliggöra för komplementering av återförsäljare, för att innefatta deras respektive nät-tjänster och enheter som kräver vidarebefodring av särskilda portar. Systemet kan minskasupportkostnader för bredbandsleverantörer och bidra till en förbättrad användarupplevelsevid konfiguration av nätverksgateways.

The heart disease Atrial Fibrillation (AFib) has increased worldwide in recent years. Untreated AFib can lead to cardiovascular complications such as stroke and heart failure. AFib is detected by physicians using Electrocardiogram (ECG). Since this disease can occur without symptoms for some patients, it can lead to late detection. Therefore, smart solutions for continuous monitoring of ECG to detect AFib is needed. This paper presents an approach to model an low-cost intelligent health monitoring system (IHMS) to classify and detect AFib in ECG using 1D Convolutional Neural Network (CNN). The core objective of this paper were to investigate the suitability of the computing architecture, edge and cloud, for an IHMS, and how complex 1D-CNN could be deployed to an edge device. Three 1D-CNN models with increased complexity was designed, trained and tested on AFib and NSR episodes collected from 25 records of the LTAF database. Each record were noise filtered and segmented into 10 sec. The best 1D-CNN model presented an accuracy of 83.93 %, 89.83 % in AUC, 84.32 % in sensitivity (AFIb), 83.46 % in specificity (NSR), 84.81 % in F1-score and 68.23 % in MCC. Two experiments into end-to-end delay and prediction time were performed todetermine the computing architectures suitability. The end-to-end delay were measured by sending ECG segments of different sizes to both computing architectures, while the prediction time were measured by deploying the designed 1D-CNN models on both computing architectures. Both measurements were added together to form the response time of the computing architectures. The edge computing architecture produced a delay around 0.019-0.377 sec and prediction time around 0.00X sec compared to cloud’s delay around 1.32-4.43 sec and 0.000X in prediction time. Resulting, that the edge computing architecture produced a lower response time and therefore considered the more suitable architecture for an IHMS. The designed 1D-CNN models had no issues in executing on the edge device, resulting in the conclusion that the most complex model to execute had 6 convolutional layers. The presented result in this paper contributes to the development of a health monitoring system in terms of choosing computing architecture platform and model complexity for a resource constraint device.

In real-time systems functional requirements are coupled to timing requirements, a specified event needs to occur at the appropriate time.  In order to ensure that timing requirements are fulfilled, there are two main approaches, static and measurement-based. The static approach relies on modeling the hardware and software and calculating upper bounds for the timing behavior. On the other hand, measurement-based approaches use timing data collected from the system to estimate the timing behavior. The usability of static and measurement-based approaches is limited in many modern systems due to the increased complexity of hardware and software architectures. Static approaches to timing and schedulability analysis are often infeasible due to their complexity. Measurement-based approaches require that design-time measurements are representative of the timing behavior at runtime, which is problematic to ensure in many cases. Designing systems that guarantee the timing requirements without excessive resource overprovisioning is a challenge. A Hidden Markov Model (HMM) describes a system where the behavior is state-dependent.  In this thesis, we model the execution time distribution of a periodic task as an HMM where the states are associated with continuous emission distributions. By modeling the execution times in this manner with a limited number of parameters, a step is taken on the path toward tracking and controlling timing properties at runtime.  We present a framework for parameter identification of an HMM with Gaussian emission distributions from timing traces, and validation of the identified models. In evaluated cases, the parameterized models are valid in relation to timing traces. For cases where design-time measurements are not representative of the system at runtime we present a method for the online adaptive update of the emission distributions of an HMM. Evaluation with synthetic data shows that the estimate tracks the ground truth distribution.  A method for estimating the deadline miss probability for a task with execution times modeled by an HMM with Gaussian emission distributions, in a Constant Bandwidth Server (CBS) is proposed. The method is evaluated with simulation and for a synthetic task with a known Markov Chain structure running on real hardware. / I realtidssystem är funktionella krav kopplade till tidskrav – en viss händelse måste inträffa vid rätt tid. För att försäkra sig om att tidskrav är uppfyllda finns två huvudsakliga metoder – statisk eller mätningsbaserad. En statisk analys baseras på modeller av hårdvara och mjukvara, och beräknar en övre gräns för tidsbeteendet. Mätningsbaserade analyser använder insamlat data från systemet för att uppskatta tidsbeteendet. Användbarheten av både statiska och mätningsbaserade metoder är begränsad i många moderna system eftersom komplexiteten hos hårdvara och mjukvara ökat. Statiska metoder är ofta omöjliga att genomföra på grund av komplexiteten. För mätningsbaserade metoder krävs att mätningarna som insamlats vid design är representativa för tidsbeteendet i drift, vilket är svårt att garantera i många fall. Att designa system som garanterar tidskraven utan överdriven resurstilldelning är en utmaning. En Hidden Markov Model (HMM) beskriver ett system med beteende som är tillståndsberoende. I denna avhandling modellerar vi exekveringstidens fördelning hos en periodisk task (uppgift) som en HMM där tillstånden är kopplade till kontinuerliga emissionsfördelningar. Genom att modellera exekveringstiderna på detta vis med ett begränsat antal parametrar, tar vi ett steg på vägen mot att följa och kontrollera tidsbeteendet i drift. Vi presenterar ett ramverk för parameteridentifiering för en HMM med Gaussiska emissionsfördelningar från tidsdata, och validering av de identifierade modellerna. De parametriserade modellerna är giltiga i relation till tidsdata i de fall som utvärderats. För fall när mätningar vid design inte är representativa för systemet i drift presenterar vi en metod för direkt adaptiv uppdatering av emissionsfördelningarna i en HMM. Utvärdering med syntetiska data visar att uppskattningen följer den sanna fördelningen. En metod föreslås för att uppskatta sannolikheten för att missa en deadline när exekveringstiden modelleras som en HMM med Gaussiska emissionsfördelningar hos en task i en Constant Bandwidth Server (CBS). Metoden utvärderas med simulering och med syntetiska program med känd Markov-struktur som körs på verklig hårdvara.

The increasing usage of electronics and software in a modern automobile enables realization of many advanced features. One such feature is autonomous driving. Autonomous driving means that a human driver’s intervention is not required to drive the automobile; rather, theautomobile is capable of driving itself. Achieving automobile autonomyrequires research in several areas, one of which is the area of automotive electrical/electronics (E/E) architectures. These architectures deal with the design of the computer hardware and software present inside various subsystems of the vehicle, with particular attention to their interaction and modularization. The aim of this thesis is to investigate how automotive E/E architectures should be designed so that 1) it ispossible to realize autonomous features and 2) a smooth transition canbe made from existing E/E architectures, which have no explicit support for autonomy, to future E/E architectures that are explicitly designed for autonomy.The thesis begins its investigation by considering the specific problem of creating autonomous behavior under cooperative driving condi-tions. Cooperative driving conditions are those where continuous wireless communication exists between a vehicle and its surroundings, which consist of the local road infrastructure as well as the other vehicles in the vicinity. In this work, we define an original reference architecture for cooperative driving. The reference architecture demonstrates how a subsystem with specific autonomy features can be plugged into an existing E/E architecture, in order to realize autonomous driving capabilities. Two salient features of the reference architecture are that it isminimally invasive and that it does not dictate specific implementation technologies. The reference architecture has been instantiated on two separate occasions and is the main contribution of this thesis. Another contribution of this thesis is a novel approach to the design of general, autonomous, embedded systems architectures. The approach introduces an artificial consciousness within the architecture, that understands the overall purpose of the system and also how the different existing subsystems should work together in order to meet that purpose.This approach can enable progressive autonomy in existing embedded systems architectures, over successive design iterations. / <p>QC 20130412</p>

Spin Torque Oscillator (STO) is a promising technology for microwave and radar applications due to its large tunability, miniature size, high operation frequency, high integration level, etc. However, the technology comes also with issues and challenges,such as low output power and spectrum impurity. For instance, in order to apply the STO technology into communication systems, an amplifier is required to compensate the STO’s low output power.     This thesis presents an amplifier for promising Magnetic Tunnel Junction (MTJ) STO devices. The motional resistance of different MTJ STO devices varies from several Ohms to hundreds Ohms, which makes the design challenging. This thesis focuses first on extracting the amplifier requirements using the state-of-the-art MTJ STO devices. The operation frequency of MTJ STO is in the range of 4-8GHzwith a -40～-60 dBm output power. Therefore, a wideband amplifier with 45-65 dB gain is required. Then based on the amplifier requirements, an amplifier topology is proposed, which is composed of two types of input balun-LNA stages depending onthe motional resistance of the STO, a broadband limiting amplifier and an outputbuffer. CG-CS architecture is suitable for the input balun-LNA in the small motional resistance case and cascoded-CS architecture is suitable for the large motional resistance case. The limiting amplifier and the output buffer are the common circuits shared by two cases via switches.     The wideband amplifier for STO is implemented using a 65nm CMOS process with 1.2 V supply and it exhibits 52.36 dB gain with 1.34-11.8 GHz bandwidth insmall motional resistance case and 59.29 dB gain with 1.171-8.178 GHz bandwidth in large motional resistance case. The simulation results show that the amplifier has very low power consumption and meets the linearity and noise performance requirements.

När tiden för utveckling av nya produkter kortas ner måste testning och verifiering utföras i ett tidigare utvecklingsstadie. Genom simulering av systemet kan tester utföras utan tillgång till det faktiska systemet och därmed kan utvecklingsprocessen accelereras. I BAE Systems Hägglunds stridsvagnar används en tröghetsnavigator som kan beräkna stridsvagnens position utan externa referenser. Test och verifiering av navigation med denna enhet i testbänk är ej fullt möjligt. Syftet med detta arbete är att kunna genomföra verklighetstrogna tester, i testbänk i utvecklingsfasen, genom att simulera navigatorns funktioner. Eftersom kommunikation med fordonssystemet ska ske i realtid samtidigt som navigationsdata läses från ett externt program, så ställs krav på att modellen har tillräcklig prestanda för att ge en verklighetstrogen simulering. Den övergripande frågeställningen i detta examensarbete är om en modell realiserad på en mikrokontroller (MCU) har tillräcklig prestanda för att användas vid simulering av en tröghetsnavigator. För att besvara frågeställningen har hårdvara för anpassning av gränssnittet mellan fordonssystem, MCU och externt program samt mjukvara för att simulera en tröghetsnavigator skapats. Därefter har modellen verifierats genom att mäta tiden för utvalda processer. Alla funktioner hos navigatorn har inte implementerats i simuleringsmodellen men resultaten visar att modellen kan användas för verklighetstrogna tester i testbänk. / When time for development of new products is shortened, testing and verification must be performed at an earlier stage of development. By simulating the system, tests can be performed without access to the actual system and thus the development process can be accelerated.  BAE Systems Hägglunds manufacture combat vehicles and use an Inertial Navigation System (INS) to calculate the combat vehicle’s position without external references. Testing and verification of navigation with this unit in the test bench is not entirely possible.  The aim of this thesis is to enable realistic tests, in a test bench in the development phase, by simulating the navigator’s functions. Since communication with the Vehicle Control System (VCS) must take place in real time at the same time as navigation data must be read from external program, the model is required to have sufficient performance to provide a realistic simulation.  The overall question in this thesis is whether a model realized on a microcontroller (MCU) has sufficient performance to be used for simulation of an INS. To answer the question at issue, hardware for adapting the interface between the VCS, MCU and external program as well as software for simulating an INS have been created. Thereafter, the model has been verified by measuring the time for selected processes.  Not all functions of the navigator have been implemented in the simulation model, but the results show that the model can be used for realistic tests in the test bench.

”Keep Talking and Nobody Explodes” är ett spel som normalt spelas med ”vitual reality”-glasögon på en spelkonsol. Spelet går ut på att två spelare ska sammabeta för att lösasex pussel på tid för att desarmera en bomb. En person ser bomben och ska förklarahur den ser ut för den andra personen som, med hjälp av en manual, ska berätta hurpusslet ska lösas baserat på utseendet. I denna rapport beskrivs utvecklingen av en fysiskvariant av detta spel. Utmaningen med att utveckla spelet var att designa inbyggdasystem som efterliknade det virtuella spelet så mycket som möjligt. I utvecklingeningick både design av elektriska kretsar och programmering av mikroprocessorer. Syftetmed rapporten är att ge ett exempel på hur en fysisk produkt kan utvecklas från envirtuell variant och vilka för- och nackdelar de båda varianterna kan ha. Resultatet frånprojektet blev ett spel som efterliknade den virtuella versionen med ett pussel, samt enkravspecifikation för vidare utveckling av pussel. / ”Keep Talking and Nobody Explodes” är ett spel som normalt spelas med ”vitual reality”-glasögon på en spelkonsol. Spelet går ut på att två spelare ska sammabeta för att lösasex pussel på tid för att desarmera en bomb. En person ser bomben och ska förklarahur den ser ut för den andra personen som, med hjälp av en manual, ska berätta hurpusslet ska lösas baserat på utseendet. I denna rapport beskrivs utvecklingen av en fysiskvariant av detta spel. Utmaningen med att utveckla spelet var att designa inbyggdasystem som efterliknade det virtuella spelet så mycket som möjligt. I utvecklingeningick både design av elektriska kretsar och programmering av mikroprocessorer. Syftetmed rapporten är att ge ett exempel på hur en fysisk produkt kan utvecklas från envirtuell variant och vilka för- och nackdelar de båda varianterna kan ha. Resultatet frånprojektet blev ett spel som efterliknade den virtuella versionen med ett pussel, samt enkravspecifikation för vidare utveckling av pussel.