The general trends in the past decade of increasing solar cell efficiency, decreasing PV system costs, increasing government incentive programs, and several other factors have all combined synergistically to reduce the barriers of entry for PV systems to enter the market and expand their contribution to the global energy portfolio. The shortcomings of current inverter functions which link PV systems to the utility network are becoming transparent as PV penetration levels continue to increase. The solution this thesis proposes is an approach to control the inverters real and reactive power output to help eliminate the problems associated with PV systems at their origin and in addition provide the grid with ancillary support services. The design, modeling, and analysis of a grid-tied PV system was performed in the PSCAD software simulation environment. Results indicate that in the presence of grid disturbances the smart inverter can react dynamically to help restore the power system back to its normal state. A harmonic analysis was also performed indicating the inverter under study met the applicable power quality standards for distributed energy resources.

The ongoing Smart Grid (SG) initiative proposes several modifications to the existing power grid in order to better manage power demands, reduce CO2 emissions and ensure reliability through several new applications. One part of the SG initiative that is currently being implemented is the Advanced Metering Infrastructure (AMI) which provides two-way communication between the utility company and the consumers' smart meters (SMs). The AMI can be built by using a wireless mesh network which enables multi-hop communication of SMs. The AMI network enables collection of fine-grained power consumption data at frequent intervals. Such a fine-grained level poses several privacy concerns for the consumers. Eavesdroppers can capture data packets and analyze them by means of load monitoring techniques to make inferences about household activities. To prevent this, in this dissertation, we proposed several privacy-preserving protocols for the IEEE 802.11s-based AMI network, which are based on data obfuscation, fully homomorphic encryption and secure multiparty computation. Simulation results have shown that the performance of the protocols degrades as the network grows. To overcome this problem, we presented a scalable simulation framework for the evaluation of IEEE 802.11s-based AMI applications. We proposed several modifications and parameter adjustments for the network protocols being used. In addition, we integrated the Constrained Application Protocol (CoAP) into the protocol stack and proposed five novel retransmission timeout calculation functions for the CoAP in order to increase its reliability. Upon work showing that there are inconsistencies between the simulator and a testbed, we built an IEEE 802.11s- and ZigBee-based AMI testbed and measured the performance of the proposed protocols under various conditions. The testbed is accessible to the educator and researchers for the experimentation. Finally, we addressed the problem of updating SMs remotely to keep the AMI network up-to-date. To this end, we developed two secure and reliable multicast-over-broadcast protocols by making use of ciphertext-policy attribute based signcryption and random linear network coding.

Skolans styrdokument ställer krav på att lärare och elever ska använda digitala medier i undervisningen och digital kompetens ses som en nyckelkomponent för ett livslångt lärande. Syftet är att analysera interaktionen mellan lärare och elever under problemlösningssituationer i matematikundervisningen med smart-board som medierande artefakt. Studien har ett sociokulturellt perspektiv. Empirin är insamlad genom video-observationer och studien är öppen och kvalitativ. Empirin består av fyra filmade och transkriberade sekvenser som innefattar fyra olika elever och hur de arbetar med problemlösning med smart-boarden som medierande artefakt. Empirin är analyserad utifrån EMA-modellen, som bygger på idéer från John Deweys pragmatiska filosofi. Resultatet visar att interaktionen styrs av läraren eftersom att det är läraren som styr över talutrymmet, men även vilka elever som ska vara delaktiga i interaktionen. Interaktionens fokus är ett sökande efter rätt svar.  Det lärande som möjliggörs i de filmade situationerna är att finna lämpliga strategier för att lösa problemet. / The school's governing documents require teachers and students to use digital media in education and digital literacy is seen as a key component of lifelong learning. The aim is to analyze the interaction between teachers and students in problem-solving situations in mathematics education with smart-board as mediating artifact. The study has a socio-cultural perspective. The empirical data is collected through video observation and the study is open and qualitative. The empirical data consists of four filmed and transcribed sequences involving four different students and how they work with problem solving with smart-board as a mediating artifact. The empirical data is analyzed by the EMA model, based on the ideas of John Dewey's pragmatic philosophy. The result shows that the interaction is controlled by the teacher because the teacher has control over the linguistic space, but he also choose which students who are getting involved in the interaction. Interaction focus is the search for the right answer. The learning that is made possible in filming situations is to find appropriate strategies to solve the problem

This thesis is a feasibility study of avirtual power plant (VPP) in centralSweden and part of a project withInnoEnergy Instinct and STRI. The VPPconsists of a wind park, small hydroplant as well as solar photovoltaic andenergy storage. The 50 kVsubtransmission network was modeled inorder to evaluate the network servicesthat could be provided by coordinatingexisting distributed energy resources inthe network. Simulations where performedusing measured hourly variations inproduction and consumption of allnetwork nodes. The studied networkservices included both reactive andactive power control.The aim of this thesis is to evaluatethe potential contribution from the VPPfor capacity firming in order to allow abalance responsible party to meet placedbids on the day-ahead spot market,minimize peak load in order to reducesubscribed power, decrease networklosses, the contribution from reactivepower control using the power convertersis studied. Comparisons of the economicgains from spot and balance markets ofthe VPP distributed energy resources aremade for each operation case.Sponsor: InnoEnergy / InnoEnergy Instinct

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This work showcases the utility of switchable materials. Included are a switchable room-temperature ionic liquid, a switchable solvent, a switchable heterogeneous catalyst system, and a switchable gel. First, the switchable ionic liquid 2-butyl-1,1,3,3-tetramethylguanidium methylcarbonate is fully investigated. Its use in a complete chemical process (including reaction, separation, reformation, and recycle) is demonstrated with several reactions. Furthermore, its potential use for bitumen separation and purification and SO2 capture/isolation are discussed, and preliminary data is presented. Next, piperylene sulfone (PS), a switchable solvent, is synthesized and fully characterized. Anionic nucleophilic substitution reactions were performed in PS, the products were isolated in high yields, and then the PS was reformed for reuse. Then, we designed an immobilized fluorous microphase system that uses F-MonoPhos to induce high enantioselectivities as a switchable heterogeneous catalyst system. Finally, stable reversible polyethyleimine-CO2 gels have been synthesized with 1-octanol. Our findings indicate that PEI-1200/octanol/CO2 gels have potential as a possible drug carrier matrix for transdermal delivery applications.

This thesis addresses the problem of local intrusion detection for SCADA (Supervisory Control and Data Acquisition) field devices in the smart grid. A methodology is proposed to detect anomalies in the communication patterns using a combination of n-gram analysis and Bloom Filter. The predictable and regular nature of the SCADA communication patterns is exploited to train the intrusion detection system. The protocol considered to test the proposed approach is MODBUS which is used for communication between a SCADA server and field devices in power system. The approach is tested for attacks like HMI compromise and Man-in-the-Middle. Bloom Filter is chosen because of its strong space advantage over other data structures like hash tables, linked lists etc. for representing sets. The advantage comes from its probabilistic nature and compact array structure. The false positive rates are found to be minimal with careful choice of parameters for Bloom Filter design. Also the memory-efficient property of Bloom Filter makes it suitable for implementation in resource constrained SCADA components. It is also established that the knowledge of physical state of the power system i.e., normal, emergency or restorative state can help in improving the accuracy of the proposed approach.

The ability of typical utility meters and advanced meters including sub-circuit metering to disaggregate residential electric loads and determine what appliances a homeowner is using at a given time in investigated. The basics of residential electricity systems, instrumentation options, and characteristics of selected residential loads are presented. This information informs a discussion on present and future disaggregation algorithms. The conclusions highlight the importance of reactive power and current harmonics in determining power consumed and identifying modern electrical devices, and raise concerns related to the ability of typical 15 minute interval utility smart meters to disaggregate loads. / text

Low resolution pharyngeal manometry is an invasive diagnostic method that has recently been used as a biofeedback device for swallowing rehabilitation. The University of Canterbury Rose Centre uses pharyngeal manometry to diagnose and rehabilitate subjects who suffer from pharyngeal mis-sequencing. Pharyngeal mis-sequencing occurs when pressure is applied simultaneously throughout the pharynx rather than sequentially. Rehabilitation can only be performed in clinic due to the need for specialized equipment and trained staff, and the invasiveness of the test limits the time that can be spent training. As an alternative method to measure the pharyngeal pressure sequence, bioimpedance has been investigated by a previous University of Canterbury Master’s student. A prototype was developed that measured bioimpedance in two locations as a proxy for pharyngeal pressure sequence. The prototype device named GULPS (Guided Utility for Latency in Pharyngeal Swallowing), measured a change in impedance during swallowing. However, the features of this waveform were inconsistent and were not present during every swallow. The frequency of the current that passes through tissue affects its path through the tissue, therefore impacting the measured impedance. To improve the consistency of the impedance measurement, the effect of current injection frequency was investigated. A modular-hardware system was created from the original design to allow testing of different injection frequencies. The hardware was further developed by replacing the method of generating the constant amplitude current injection signal. The improvement to the design resulted in a differently-shaped waveform to that of the previous prototype, including a new feature. This feature is a single peak that occurred in both channels and was reproduced in every swallow. Experimentation showed that the features were not obviously frequency dependent. The separation between the peaks of the two impedance channels was compared with the separation between the two pressure peaks recorded during simultaneous pharyngeal manometry but there was no significant correlation between the two measures of peak-peak separations. Two alternative hardware/signal conditioning changes were trialled: electrical isolation of each channel and a subtraction method, which aims to remove the effect of the changing impedance between the two electrode channels. Electrical isolation of the two channels had no effect on the impedance waveforms. However, the subtraction method produced a different output and requires further investigation as the output was inconsistent. Bluetooth communication was integrated into the GULPS hardware, and a corresponding Android Application (App) was written. The developed App was successful in displaying the impedance measurement output and adds greater user flexibility, allowing the user to interface with the bioimpedance measurement hardware from their tablet or phone. With no measured significant correlation between GULPS and pharyngeal manometry, further research needs to be performed to better relate the features measured by GULPS to those seen during pharyngeal manometry. Until this can be achieved, the GULPS device cannot replace pharyngeal manometry for biofeedback-based rehabilitation of pharyngeal mis-sequencing.

The digitalization of the electricity grid can provide politicians and different kinds of companies with solid benefits in terms of efficiency, renewable integration and control. However, some part of the deployment of smart grids is only possible with the engagement of consumers who are required to change their behavior significantly. This behavioral change can be induced if energy companies (incumbents and new players) adopt business models that do not sell a technology but use technology to wrap a viable business case around the core task to “solving a customer’s problem”. This paper investigates different business models in the smart grid context on their possibility to diffuse in the market. Furthermore, it stresses that the emergence of smart grids will provide incumbents and new companies with new possibilities to offer new services. However for incumbent companies these new roles, increased competition, and new services also imply challenges. Old paradigms of the traditionally conservative utilities need to be changed. This paper finds out that the electricity consumer of today is not uniform, but rather can be divided into four segments who seem to describe the market well (at least in Germany) and have very different needs and preferences. In order to become agents of change in the future utilities will have to transform their business model, if they are not already on their way to do so. Throughout the paper, a EU (European Union) and North American perspective is considered, with primary focus on Sweden, Germany, and the USA.