This thesis explores the transformations of evidence in health research synthesis studies – studies that bring together evidence from a number of research reports on the same/ similar topic. It argues that health research synthesis is a broad and intriguing field in a state of pre-formation, in spite of the fact that it may appear well established if equated with its exemplar method – the systematic review inclusive of meta-analysis. Transformations of evidence are processes by which pieces of evidence are modified from what they are in the primary study report into what is needed in the synthesis study while, supposedly, having their integrity fully preserved. Such processes have received no focused attention in the literature. Yet they are key to the validity and reliability of synthesis studies. This work begins to describe them and explore their frequency, scope and drivers. A ‘meta-scientific’ perspective is taken, where ‘meta-scientific’ is understood to include primarily ideas from the philosophy of science and methodological texts in health research, and, to a lesser extent, social studies of science and psychology of science thinking. A range of meta-scientific ideas on evidence and factors that shape it guide the analysis of processes of “data extraction” and “coding” during which much evidence is transformed. The core of the analysis involves the application of an extensive Analysis Framework to 17 highly heterogeneous research papers on cancer. Five non-standard ‘injunctions’ complement the Analysis Framework – for comprehensiveness, extensive multiple coding, extreme transparency, combination of critical appraisal and critique, and for first coding as close as possible to the original and then extending towards larger transformations. Findings suggest even lower credibility of the current overall model of health research synthesis than initially expected. Implications are discussed and a radical vision for the future proposed.

This thesis examines charging of electric vehicles with charging power of 3,7 kW, in connection to an apartment building in Sweden. Also the power consumption of six electric vehicles are investigated. The charging-simulations of the electric vehicles were performed with the electric vehicle charging model (Grahn-Munkhammar) in MatLab. To simulate general energy use for a housing complex, the measured energy consumption per year for a building with 24 apartments was used. Three different systems with charging over a year were simulated. One system included six different models of electric vehicles, another system included six Tesla model S and yet another one included six Mitsubishi Outlanders. The simulations of electric vehicle charging resulted in a charging pattern with a considerable variability and an aggregation effect with a value over 20 % for all three systems. Results show that electric vehicle charging adds to the power peaks of the apartment building. However, according to the model, the aggregation effect implies that effect values of total electric vehicle charging were not harmful to an apartment building with a fuse of 63 A.

The backbone of our industrialised society and economy is electricity. To avoid a catastrophic situation, a plan for how to act during a power shortage is crucial. Previous research shows that decision models provide support to decision makers providing efficient energy rationing during power shortages in the Netherlands, United States and Canada. The existing research needs to be expanded with a group decision model to enable group decisions. This study is conducted with a case study approach where the Swedish emergency preparedness plan in case of power shortage, named Styrel, is explored and used to evaluate properties of a proposed group decision model. The study consist of a qualitative phase and a quantitative phase including a Monte Carlo simulation of group decisions in Styrel evaluated with correlation analysis. The qualitative results show that participants in Styrel experience the group decisions as time-consuming and unstructured. The current decision support is not used in neither of the two counties included in the study, with the motivation that the preferences provided by the decision support are misleading. The proposed group decision model include a measurable value function assigning values to priority classes for electricity users, an additive model to represent preferences of individual decision makers and an additive group decision model to aggregate preferences of several individual decision makers into a group decision. The conducted simulation indicate that the proposed group decision model evaluated in Styrel is sensitive to significant changes and more robust to moderate changes in preference differences between priority classes.

Thesis (PhD (Chemistry and Polymer Science)--University of Stellenbosch, 2006. / Synthetic peptides derived from the active core of a natural antimicrobial peptide were used as a template for the design of novel bolaamphiphilic peptides and hybrid molecules. The amphiphilic character of the original compounds was modified by using non-natural amino acids (AAs) – such as ω-AA – and varying the hydrophobic content. The outcomes of these modifications were studied focusing on structural and biological properties. Because of the bolaamphiphilic character, the alternation of polar and non-polar AAs and the use of hydrophobic AAs such as tyrosine and leucine, these novel molecules were designed to undergo self-assembly in response to certain stimuli (e.g. a pH increase). This significant property was investigated by means of different tools, such as fluorescence measurements, electron microscopy (EM), Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD). By using fluorescence it was possible to determine the critical aggregation concentration (CAC) of the new compounds. Differences in amino acid composition, which were reflected into diverse secondary structures and hydrophobicity (H), resulted in different CAC values and aggregation profiles. The data were consistent with the literature and showed that (i) the aggregation of these basic compounds was triggered by a pH increase, (ii) the use of hydrophobic AA highly augmented the self-assembly tendency while (iii) the presence of proline strongly reduced it. EM revealed the morphology of the peptide assemblies: microtubes and microvesicles were identified and characterised by dimensions of 500 nm to 2 μm. The presence of 3-way junctions and vesicles budding out of the microtubes demonstrated that the self-assembly is a dynamic process. The aggregation was confirmed by FT-IR spectroscopy, by studying the dried peptide assemblies and the significant spectral signs the process left, especially in the amide II envelope. The relationship between hydrophobicity and self-assembly was expanded by experimentally and theoretically determining the hydrophobic content of the novel bolaamphiphiles. Data from liquid chromatography and computational calculations (two common ways used to determine the hydrophobicity of a given molecule) correlated well with the tendency to self-assemble, as expressed by CAC values. Importantly, some structural parameters (such as the presence of β-turn induced by proline) also showed significant influence on the aggregation, highly limiting the role of the peptides’ hydrophobicity. These novel peptide bolaamphiphiles displayed a very low haemolytic action and retained some antimicrobial activity at high concentrations against both Gram-positive and -negative bacteria. Unfortunately, the activity was greatly reduced at low concentrations, as clearly demonstrated by the use of two antimicrobial tests. The inability to provoke cell lysis was also evident when using liposomes mimicking a negative bacterial membrane. The loss of activity is possibly related to the modifications of the three-dimensional structure caused by the use of ω-AA and proline, which strongly alter the secondary structure. The results of this study were valuable in terms of understanding the relationships between self-assembly and structural parameters, such as AA compositions, hydrophobicity and secondary structure. Possible applications of the synthesised compounds were however limited as a result of the loss of the biological activity at low concentrations.

As a post-Soviet economy, Ukraine has inherited substantial production assets and qualified personnel. However, the economy was dominated by large-scale enterprises designed for much bigger markets. After the collapse of the Soviet Union Ukrainian firms faced lack of planning, breaks in contacts with their former suppliers and customers, and distortion of prices. There was a clear need in restructuring of the entire economy. Restructuring included splitting firms into smaller parts and privatization. The first phase of transition was completed by 2000 when the output grew for the first time after a long recession in nineties, and most firms became private property. In this work I explore trends in geographic and industrial concentration of Ukrainian manufacturing firms over the period of 2001 to 2005. I found that this period was characterized by relocation of firms between sectors and between regions, as well as by an increase in economic concentration of industries. The speed of adjustment was different for various sectors and even for different industries within manufacturing. Even though the economy is still dominated by large firms, the average firm size decreases due to a rapid growth in the number of new firms. Geographically, manufacturing tends to increasingly concentrate mostly around a few big cities, apparently at the expense of other regions. I also estimate the external scale effects and compare them with Western studies. In particular I focus on machinery and high tech. I found strong localization and urbanization effects in both industry groups. An important contribution of this work is the analysis of the effect of ownership structure on agglomeration economies. I found that private firms tend to enjoy external scale effects to a greater extent than state owned, and foreign owned firms appear to be the most efficient in extracting benefits form agglomeration. Aggregation of the data may distort the estimates of agglomeration effects. I show that most effects take place at the nearest neighborhoods. When the physical distance between firms increases agglomeration effects attenuate quickly. However, localization effects reveal themselves at different level of industrial aggregation for various industries. This may reflect more complicated relationships within sectors and requires further analysis.

The gap between abstract, mathematics-oriented research in cryptography and the engineering approach of designing practical, network security protocols is widening. Network researchers experiment with well-known cryptographic protocols suitable for different network models. On the other hand, researchers inclined toward theory often design cryptographic schemes without considering the practical network constraints. The goal of this dissertation is to address problems in these two challenging areas: building bridges between practical network security protocols and theoretical cryptography. This dissertation presents techniques for building performance sensitive security protocols, using primitives from linear feedback register sequences (LFSR) sequences, for a variety of challenging networking applications. The significant contributions of this thesis are: 1. A common problem faced by large-scale multicast applications, like real-time news feeds, is collecting authenticated feedback from the intended recipients. We design an efficient, scalable, and fault-tolerant technique for combining multiple signed acknowledgments into a single compact one and observe that most signatures (based on the discrete logarithm problem) used in previous protocols do not result in a scalable solution to the problem. 2. We propose a technique to authenticate on-demand source routing protocols in resource-constrained wireless mobile ad-hoc networks. We develop a single-round multisignature that requires no prior cooperation among nodes to construct the multisignature and supports authentication of cached routes. 3. We propose an efficient and scalable aggregate signature, tailored for applications like building efficient certificate chains, authenticating distributed and adaptive content management systems and securing path-vector routing protocols. 4. We observe that blind signatures could form critical building blocks of privacypreserving accountability systems, where an authority needs to vouch for the legitimacy of a message but the ownership of the message should be kept secret from the authority. We propose an efficient blind signature that can serve as a protocol building block for performance sensitive, accountability systems. All special forms digital signatures—aggregate, multi-, and blind signatures—proposed in this dissertation are the first to be constructed using LFSR sequences. Our detailed cost analysis shows that for a desired level of security, the proposed signatures outperformed existing protocols in computation cost, number of communication rounds and storage overhead.

Ce travail est dédié à l'étude du comportement agrégatif chez la fourmi Lasius niger afin de caractériser le phénomène au niveau collectif, par l'étude de la dynamique et de la structure agrégative, et au niveau des mécanismes sous-tendant le phénomène par l’analyse des comportements individuels des fourmis. Nous avons montré expérimentalement et vérifié par la modélisation que l’agrégation est essentiellement liée à un phénomène amplificateur : plus l’agrégat est de grande taille, plus les fourmis y restent longtemps. Nos résultats indiquent que le niveau d’agrégation et la structure formée sont dépendants de plusieurs facteurs comme la densité et la surface disponible : une évolution de la structure agrégative des nourrices est observée, passant d’un grand agrégat stable pour les petites densité-surface à plusieurs agrégats à hiérarchie de taille moins marquée pour les grandes densité-surface. L’agrégation est aussi influencée par la caste éthologique des fourmis, les nourrices s’agrégeant en un agrégat stable de grande taille, les fourrageuses en quelques petits agrégats instables. Cette différence s’explique par une probabilité plus faible des fourrageuses à rester dans l’agrégat. Dans les groupes mixtes, les fourmis gardent les caractères propres à leur caste, ne semblant pas influencées par la caste de l’individu rencontré. Enfin, l’agrégation diffère quantitativement mais non qualitativement selon l’espèce utilisée : nos études sur Crematogaster scutellaris, Atta sexdens-rubropilosa, Solenopsis invicta, Pheidole pallidula, Linepithema humile, Myrmica rubra et M. ruginodis montrent une grande variété de réponses, en nombre et en taille d’agrégats, qui est aussi fonction de la caste de fourmis utilisée. Une constance, cependant, apparaît dans nos résultats : les nourrices paraissent mieux s’agréger que les fourrageuses. Ces résultats sont discutés en fonction de leur valeur adaptative pour la colonie et d’un lien possible avec la distribution spatiale des individus à l’intérieur du nid./This work is dedicated to the study of the aggregative behaviour in the ant Lasius niger in order to characterize the phenomenon at the collective level by a study of the dynamic and the collective structure, and at the individual level to understand the mechanisms underlying the phenomenon. We demonstrated experimentally and verified by a model that aggregation is essentially due to an amplificatory phenomenon: the greater the ant numbers in a cluster, the greater the time spent by an ant inside this cluster. Our results indicate that the aggregation level and the form of the collective structure depend on different factors such as the density and the surface: for brood-tenders, an evolution of the aggregative structure is observed shifting from a large stable aggregate for low density-surface to several smaller clusters with a less pronounced hierarchical size for the greater density-surface. Aggregation is also influenced by the ethological caste of the ant: the brood-tenders aggregate in a big stable cluster and the foragers in some unstable clusters. This difference is explained by a smaller probability of foragers to stay inside the cluster. In mixed groups, ants keep their own characteristics, not appearing to be influenced by the caste of the individual encountered. Finally, aggregation is influenced by the ant species: our studies on Crematogaster scutellaris, Atta sexdens-rubropilosa, Solenopsis invicta, Pheidole pallidula, Linepithema humile, Myrmica rubra and M. ruginodis show us a large variety of responses, in the number and the size of the clusters, which is also a function of the caste of ants which is used. A constant result, nevertheless, appears in our results: brood-tenders seem to aggregate better than foragers. These results are discussed in term of their adaptive value for the colony and a possible link with the spatial distribution of ants inside the nest.

<p>When using Voice over IP (VoIP) in Wireless Mesh Networks the overhead induced by the IEEE 802.11 PHY and MAC layer accounts for more than 80% of the channel utilization time, while the actual payload only uses 20% of the time. As a consequence, the Voice over IP capacity is very low. To increase the channel utilization efficiency and the capacity several IP packets can be aggregated in one large packet and transmitted at once. This paper presents a new hop-by-hop IP packet aggregation scheme for Wireless Mesh Networks.</p><p>The size of the aggregation packets is a very important performance factor. Too small packets yield poor aggregation efficiency; too large packets are likely to get dropped when the channel quality is poor. Two novel distributed protocols for calculation of the optimum respectively maximum packet size are described. The first protocol assesses network load by counting the arrival rate of routing protocol probe messages and constantly measuring the signal-to-noise ratio of the channel. Thereby the optimum packet size of the current channel condition can be calculated. The second protocol, which is a simplified version of the first one, measures the signal-to-noise ratio and calculates the maximum packet size.</p><p>The latter method is implemented in the ns-2 network simulator. Performance measurements with no aggregation, a fixed maximum packet size and an adaptive maximum packet size are conducted in two different topologies. Simulation results show that packet aggregation can more than double the number of supported VoIP calls in a Wireless Mesh Network. Adaptively determining the maximum packet size is especially useful when the nodes have different distances or the channel quality is very poor. In that case, adaptive aggregation supports twice as many VoIP calls as fixed maximum packet size aggregation.</p>

<p>3D city models have been widely used in different applications such as urban planning, traffic control, disaster management etc. Effective visualisation of 3D city models in various scales is one of the pivotal techniques to implement these applications. In this thesis, a framework is proposed to visualise the 3D city models both online and offline using City Geography Makeup Language (CityGML) and Extensible 3D (X3D) to represent and present the models. Then, generalisation methods are studied and tailored to create 3D city scenes in multi-scale dynamically. Finally, the quality of generalised 3D city models is evaluated by measuring the visual similarity from the original models.</p><p> </p><p>In the proposed visualisation framework, 3D city models are stored in CityGML format which supports both geometric and semantic information. These CityGML files are parsed to create 3D scenes and be visualised with existing 3D standard. Because the input and output in the framework are all standardised, it is possible to integrate city models from different sources and visualise them through the different viewers.</p><p> </p><p>Considering the complexity of the city objects, generalisation methods are studied to simplify the city models and increase the visualisation efficiency. In this thesis, the aggregation and typification methods are improved to simplify the 3D city models.</p><p> </p><p>Multiple representation data structures are required to store the generalisation information for dynamic visualisation. One of these is the CityTree, a novel structure to represent building group, which is tested for building aggregation. Meanwhile, Minimum Spanning Tree (MST) is employed to detect the linear building group structures in the city models and they are typified with different strategies. According to the experiments results, by using the CityTree, the generalised 3D city model creation time is reduced by more than 50%.</p><p> </p><p>Different generalisation strategies lead to different outcomes. It is important to evaluate the quality of the generalised models. In this thesis a new evaluation method is proposed: visual features of the 3D city models are represented by Attributed Relation Graph (ARG) and their similarity distances are calculated with Nested Earth Mover’s Distance (NEMD) algorithm. The calculation results and user survey show that the ARG and NEMD methods can reflect the visual similarity between generalised city models and the original ones.</p> / QC 20100923 / ViSuCity Project

<p>Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets.</p><p>The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV.</p><p>Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia.</p><p>There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument.</p><p>Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.</p>