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The last three decades have seen significant advances in the wireless communication field. As the data rates of wireless systems are increasing, the demand for mobile services also is increasing rapidly. Like other natural resources, radio spectrum suitable for mobile wireless communications is also limited. In order to keep up with this ever increasing demand, there is a requirement of new signal processing algorithms. Diversity is a technique used in wireless systems to combat the effects of fading and thereby improve reliability of data transfer. There are many ways in which algorithms can exploit diversity in wireless channels. Hybrid-automatic repeat request (H-ARQ) schemes and relaying mechanisms are two such diversity extracting techniques. Even though these diversity achieving techniques have been well understood in theory, there are many ways in which one can optimize these techniques for specific application scenarios.In this thesis, we focus on improving the performance of retransmission schemes and relaying systems. In the first part of the thesis, we improve the performance of H-ARQ schemes in the 3GPP- long term evolution (LTE) system by improving the performance of feedback signaling. We employ complex-field coding to extract the inherent frequency diversity available in the resources. Next, we provide a sub-optimal solution to the outage-optimal power allocation problem in incremental redundancy based H-ARQ system, whose performance is practically the same as that of the optimal solution. In the later part of the thesis, we propose a retransmission scheme based on superposition coding (SPC) for the symmetric relaying scenario. We provide packet error probability (PEP) expressions and solutions for the optimal fraction of power allocated for the partners' data. Finally, we study the optimal bits-to-symbol mappings for SPC and its effect on an H-ARQ scheme and the symmetric relaying scenario using SPC.

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Denna studie argumenterar för att dagens mediesamhälle fungerar som en hybrid, där sociala medier och traditionella medier lever och verkar i symbios. Det som får tillräckligt stor spridning på sociala medier kan påverka nyhetsdagordningen och därmed vad allmänheten anser vara viktigt för tillfället. Detta är betydelsefullt för biståndsorganisationer som, för att kunna nå ut till många och öka chanserna till att samla in pengar, är i behov av att deras sak får plats på dagordningen. Studien baseras på en kvantitativ innehållsanalys av samtliga publicerade videoklipp av Sverige för UNHCR på Facebook under 2015. Variablerna baserades på teorier om viralitet, som ursprungligen har utvecklats inom marknadsföring. Där ingick teori om social delning av känslor, social nätverksteori, self-determination theory samt marknadsföringsmodellen ”the Dragonfly effect”. Studien visade hur teorierna kunde utnyttjas även i detta sammanhang, om de anpassades utifrån kontexten. Resultatet visade att the Dragonfly effect tycks vara en lämplig modell i denna kontext. Videon ”Search for Syria” utmärkte sig i detta urval, genom att ha högst antal visningar kombinerat med en förhållandevis hög andel användarresponser, som bidrar till spridningen. Alla fyra steg inom Dragonfly-modellen kunde identifieras i denna video, vilket indikerar att detta är en lämplig modell för att öka chansen till spridning i denna kontext. Studien fann också att urvalet av videoklipp generellt inte var konstruerade på ett sätt som uppmuntrar till spridning. Vidare noterades att starka känslomässiga inslag, så som provokativa och obehagliga scener, förekommer mer i videor som fått flest visningar. Samtidigt tycks videoklipp med en större andel positiva och hoppfulla inslag få större användarrespons i form av ”gillningar”, kommentarer och delningar.

Doctor of Philosophy / Department of Chemistry / Eric A. Maatta / Polyoxometalates are self-assembled metal-oxygen anionic clusters formed primarily by Mo, W and the Group V transition metals. Their structural, chemical and physical diversity have attracted much attention from fields such as catalysis, imaging, magnetic materials, medicine and photochromism. While many of these inorganic systems are easy to prepare, their conversion to hybrid inorganic-organic materials through functionalization is an ongoing challenge. Two approaches used for functionalization involve the insertion of metal-nitrido fragments into a lacunary polyoxometalate or the direct replacement of the terminal oxo ligands with the isoelectronic organoimido [NR][superscript]2-, hydrazido [NNR[subscript]2][superscript]2-, nitrosonium [NO][superscript]+ and diazenido [NNR][superscript]+ ligands. The later process has been proven successful with a variety of different nitrogenous ligands. One of our group's goals has been to synthesize a functionalized hexamolybdate species capable of metal coordination, with the ultimate goal of forming self-assembled networks. However, previous results have been unsuccessful due to the electron withdrawing effect of the cluster which is transmitted to the metal binding site. In order to overcome this effect, several new organoimido delivery reagents (phosphineimines, isocyanates and arylamines) containing electron donating substituents have been synthesized and characterized. Attempts to attach these species to hexamolybdate are described. The synthesis and characterization of biarylimido ligands bearing remote σ-donor functionalities and their incorporation into the hexamolybdate cluster will be described. A new and exciting avenue of polyoxometalate chemistry will be demonstrated through the successful metal coordination of the biarylimido functionalized hexamolybdate to a ruthenium(II) metalloporphyrin. This also brings the hexamolybdate polyoxometalate one step closer to being capable of forming the supramolecular architectures mentioned earlier. A chromium(V) nitrido polyoxometalate has been synthesized and characterized from a lacunary Keggin precursor, in collaboration with our colleagues in Paris. The ability of this complex as a nitrogen transfer reagent will be explored. An alternative synthetic route to the osmium-nitrido-Dawson species, [(OsN)P[subscript]2W[subscript]17O[subscript]61][superscript]4- will also be described. These nitrido species could be an entry point to other derivatives through reactions with various nucleophiles and electrophiles.

Master of Science / Department of Architectural Engineering and Construction Science / Fred L. Hasler / On-site energy production is becoming increasingly prevalent in building systems design with a renewed public awareness of sustainability, decreased energy resources, and an increase in the requirements of local and federal energy codes. Systems such as photovoltaics and solar thermal collectors have been implemented in designs to meet these challenges. The emerging technology of hybrid photovoltaic thermal (PVT) offers the potential to combine these systems into one contained module. A hybrid PVT system can simultaneously produce thermal and electrical energy, maximizing the use of available surface area available for energy production. Hybrid PVT can be implemented using PVT air collectors, PVT liquid collectors, and ventilated PV facades. Hybrid PVT is gaining interest at the academic level and is being applied at the residential level. Several commercial hybrid PVT products are currently manufactured, but options are limited. This report will evaluate PV, solar thermal collector, and hybrid PVT technologies, discuss the various components required for these systems, and present advantages and disadvantages of these systems. For an example elementary school design, the report will compare monthly energy production of the various systems, evaluating their ability to supply the peak loads of an example building design. Estimated first costs and operating and maintenance costs will be evaluated. The report will also quantify the ideal balance of PV and solar thermal collectors for the example based on loads and simple payback. Conclusions will be made about the current state of hybrid PVT and what steps need to be taken for it to be effectively implemented in the commercial building market.

Published Article / The paper highlights the design, development and evaluation of a hybrid convective-far-infrared (FIR) dehydrator for the purpose of drying fruit. The methodology followed is based on an experimental and practical approach. The application of the dryer for this study is aimed at the production of apple chips as well as other types of fruit chips and the more common dried fruit. The fruit dryer proposed uses both infrared energy and convective heating to effectively and efficiently dehydrate apple slices to produce dried apple chips. The apple chips are produced in very short time frames and accomplished by using relatively low heater power. These types of apple chip snacks also contribute to the more healthy variety of snacks available on the market.

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Human papilloma virus (HPV) is a ubiquitous virus implicated in a growing list of cancers, particularly cervical cancer‐ the second most common cancer among women worldwide. Although persistent infection with high‐risk oncogenic HPVs such as types ‐16 or ‐18 is necessary, additional factors like co‐infection with other viruses can play a role in cancer progression. Protein‐protein interactions play a central role in the infection, survival and proliferation of the virus in the host. Although some interactions of HPV proteins are well characterised, it is essential to discover other key viral interactions to further improve our understanding of the virus and to use this knowledge for the development of newer biomarkers and therapeutics. The aim of this study was to systematically analyse the interactions of HPV‐16 proteins using yeast two‐hybrid (Y2H). To achieve this, a clone collection of the viral proteome was generated by recombinatorial cloning and three independent Y2H screens were performed: (i) Intra‐viral screen to identify interactions among the HPV‐16 proteins; (ii) Inter‐viral screen to identify interactions with proteins of Herpes Simplex Virus (HSV) which is suggested to be a co‐factor; and (iii) Virus‐host screen to identify novel cellular binding partners. The intra‐viral Y2H screen confirmed some of the previously known interactions and also identified binding of the E1 and E7 proteins. Deletion mutagenesis was performed to map the interaction domains to the amino‐terminal 92 amino acids of E1 and carboxy‐terminal CxxC domain of E7. Replication assays suggest a possible repression of E1‐mediated episomal replication by direct binding of E7. The inter‐viral Y2H screen identified interactions of HPV proteins with seventeen HSV‐1 proteins including transcriptional regulator ICP4 and neurovirulance factor ICP34.5. The biological relevance of these interactions in the context of co‐infection is discussed. The virus‐host screen performed against a human cDNA library identified 54 interactions, a subset of which was validated by biochemical pull‐down assays. The functional relevance of an interaction between E7 and a proto‐oncogene spermatogenic leucine zipper protein (SPZ1) was further investigated suggesting a role of SPZ1 in E7‐mediated cell proliferation. The work presented in this thesis identifies several novel interactions of HPV proteins. Future work will involve the in‐depth elucidation of biological relevance of these interactions. In particular, the interactions of E7 with E1 and SPZ1 are of great interest to improve our understanding of the life cycle and pathogenesis of the virus which can be applied for improved strategies of prevention and treatment of malignancies caused by HPV.