Constraint programming (CP) is a technology in which a combinatorial problem is modeled declaratively as a conjunction of constraints, each of which captures some of the combinatorial substructure of the problem. Constraints are more than a modeling convenience: every constraint is partially implemented by an inference algorithm, called a propagator, that rules out some but not necessarily all infeasible candidate values of one or more unknowns in the scope of the constraint. Interleaving propagation with systematic search leads to a powerful and complete solution method, combining a high degree of re-usability with natural, high-level modeling. A propagator can be characterized as a sound approximation of a constraint on an abstraction of sets of candidate values; propagators that share an abstraction are similar in the strength of the inference they perform when identifying infeasible candidate values. In this thesis, we consider abstractions of sets of candidate values that may be described by an elegant mathematical formalism, the Galois connection. We develop a theoretical framework from the correspondence between Galois connections and propagators, unifying two disparate views of the abstraction-propagation connection, namely the oft-overlooked distinction between representational and computational over-approximations. Our framework yields compact definitions of propagator strength, even in complicated cases (i.e., involving several types, or unknowns with internal structure); it also yields a method for the principled derivation of propagators from constraint definitions. We apply this framework to the extension of an existing CP solver to constraints over strings, that is, words of finite length. We define, via a Galois connection, an over-approximation for bounded-length strings, and demonstrate two different methods for implementing this overapproximation in a CP solver. First we use the Galois connection to derive a bounded-length string representation as an aggregation of existing scalar types; propagators for this representation are obtained by manual derivation, or automated synthesis, or a combination. Then we implement a string variable type, motivating design choices with knowledge gained from the construction of the over-approximation. The resulting CP solver extension not only substantially eases modeling for combinatorial string problems, but also leads to substantial efficiency improvements over prior CP methods.

This thesis examines talking books at public libraries. The thesis focuses on what the digital evolution has cometo mean in terms of Internet-based access to talking books. The survey is based on interviews with library staff and a socio-cultural theoretical perspective. The survey aims to examine the library's talking book function as a phenomenon in which cognitive, physical, communicative and temporal dimensions are considered. The survey demonstrates that the library staff associates talking books with goals concerning everyone's right to access to literature and reading and libraries intermediary role in this regard, which these often tied to broader public librari -es goals concerning the promotion of reading, democracy, accessibility and where the establishment of the service Egen nedladdning is understood from thoughts of greater, easier and more efficient access to talking books for the talking book reader, and as an opportunity for independence for the same. Physical talking books are disussedas a tool that can be used to establish and convey the talking book function in library premises. In terms o finformation dissemination and surrounding activities are made visible not least a network-based method and spontaneous meetings. Egen nedladdning and the app Legimus imparts opportunities for those expressing interestin the face of these, but older talking book readers can communicate a smaller interest in the use of these tools. Recording sessions for the service Egen nedladdning, and possible challenges in connection to these, are also takeninto account and also information and knowledge acquisition among librarians in the case of talking books. Also, the communication and meetings between the talking book readers and library staff are discussed, and the service Egen nedladdning impact on this question. The essay ends with a discussion in which the talking book function at public libraries is discussed based on themes of space, technology and literature brokering and where operational opportunities and challenges in this regard are outlined. This is a two years master’s thesis in Libraryand information science.

Submitted in complete fulfillment of the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, Durban, South Africa. 2014. / The global demand for green technology has created a need to search for microbes that can play an active role in advancing a greener and cleaner future. Microbial enzymes are nature’s keys to life and their efficiency, specificity and environmental-friendliness has lead to their increased use in industrial processes. Thermomyces lanuginosus is a thermophilic fungus that can degrade plant biomass and produces a variety of enzymes that have industrial application. The fungus T. lanuginosus SSBP has been reported in literature to produce the highest level of xylanase among other Thermomyces strains and some of its enzyme s viz., amylase and lipase are already being used. Because of this ability, it has been identified as one of the organisms that can have various industrial applications. Although a few proteins from this fungus have been cloned and used commercially, the vast majority are still unknown. In order to identify new protein candidates and understand their biochemical interactions, the T. lanuginosus genome (DNA) and the transcriptome (mRNA) were sequenced using 454 Roche and Solexa sequencing platforms. Genome and transcriptome data was assembled using Newbler software forming a genome size of 23.3 Mb contained 30 scaffolds. Protein prediction identified 5105 candidates as protein-coding genes and these gene models were supported by expressed sequence tag and transcriptomic data. The annotated data was assembled into metabolic pathways in order to identify functional pathways and validate the accuracy of the annotation process. T. lanuginosus is usually found in composting plant material thus protein related to plant hydrolysis were analysed. The total number of plant biomass-degrading and related proteins that fall into the carbohydrate-active enzyme (CAZy) family was 224. Most of these proteins were similar to proteins found in other filamentous fungi. Surprisingly, T. lanuginosus contained a single gene coding for xylanase which hydrolyses xylan although this organism is well known for being among the highest producers of this enzyme. An important subset of the above group of proteins is the cellulose degrading-proteins as this can be used in biofuel production. Eight candidates belonging to this group were identified, making this fungus significant in the biofuels. Among the eight cellulase candidates, phylogenetic analysis revealed that three of them were closely related to Trichoderma reesei, a well known industrial cellulase-producer. Utilization of cellulase-related compounds was validated by phenotypic microarray experiments, with cellobiose having inducing biomass in T. lanuginosus. Proteins that are involved in high temperature survival are vital for the survival. of this thermophilic fungus. Interestingly, T. lanuginosus contains 19 heat shocking proteins which are responsible for thermostability. Another adaptation identified in this fungus is the accumulation of trehalose to combat heat stress. Furthermore, T. lanuginosus contains the highest reported number methyltransferases, which have been linked to producing thermostable proteins and higher energy production. Also because of this organism’s ability to grow on composting environments, the assimilation and ability to produce biomass on different carbon sources were analysed using phenotypic microarray technique. The results showed that xylose was the best compound to induce biomass followed by trehalose, maltose and maltotriose. The genomic sequencing of this fungus has provided valuable information that can be used for various biotechnological applications, as well as providing greater insights into its thermostability. Understanding the metabolic pathways involved may allow for manipulation to increase production of these enzymes or cloning into other hosts. This can have an impact in the field of biofuel production and other plant biomass-related processes.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 vi, 92 leaves / Interest in xylanases from different microbial sources has increased markedly in the past decade, in part because of the application of these enzymes in a number of industries, the main area being the pulp and paper industry. While conventional methods will continue to be applied to enzyme production from micro-organisms, the application of recombinant DNA techniques is beginning to reveal important information on the molecular basis and this knowledge is now being applied both in the laboratory and commercially. In this study, a directed evolution strategy was used to select an enzyme variant with high thermostability. This study describes the use of error-prone PCR to modify the xylanase gene from Thermomyces lanuginosus DSM 5826, rendering it tolerant to temperatures in excess of 80°C. Mutagenesis comprised of different concentrations of nucleotides and manganese ions. The variants were generated in iterative steps and subsequent screening for the best mutant was evaluated using RBB-xylan agar plates. The optimum temperature for the activity of xylanases amongst all the enzyme variants was 72°C whilst the temperature optimum for the wild type enzyme was 70°C. Long term thermostability screening was therefore carried out at 80°C and 90°C. The screen yielded a variant which had a 38% improvement in thermostability compared to the wild type xylanase from pX3 (the unmutated gene). Successive rounds of error-prone PCR were carried out and in each round the progeny mutant displayed better thermostability than the parent. The most stable variant exhibited 71% residual activity after 90 minutes at 80˚C. Sequence analysis revealed four single amino acid residue changes that possibly enhanced their thermostabilities. This in vitro enzyme evolution technique therefore served as an effective tool in improving the thermostable property of this xylanase which is an important requirement in industry and has considerable potential for many industrial applications.

Submitted in fulfillment for the requirement of a Degree of Master of Technology: Biotechnology, in the Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa, 2009. / Protein engineering has provided a key for adapting naturally-occurring enzymes for industrial processes. However, several obstacles have to be overcome after these proteins have been adapted, the main one being finding a suitable host to over-express these recombinant protein. This study investigated Saccharomyces cerevisiae, Pichia pastoris and Escherichia coli as suitable expression hosts for a previously modified fungal xylanase, which is naturally produced by the filamentous fungus, Thermomyces lanuginosus. A xylanase variant, NC38, that was made alkaline-stable using directed evolution was cloned into four different vectors: pDLG1 with an ADH2 promoter and pJC1 with a PGK promoter for expression in S. Cerevisiae, pBGP1 with a GAP promoter for expression in P. pastoris and pET22b(+) for expression in E. Coli BL21 (DE3). S. Cerevisiae clones with the p DLG1-NC38 combination showed very low activity on the plate assay and were not used for expression in liquid media as the promoter was easily repressed by reducing sugars used during production experiments. S. cerevisiae clones carrying pJC1-NC38 were grown in media without uracil while P. Pastoris clones were grown in YPD containing the antibiotic, zeocin and E. Coli clones were grown in LB with ampicillin. The levels of xylanase expression were then compared between P. Pastoris, S. cerevisiae and E. coli. The highest recombinant xylanase expression was observed in P. Pastoris with 261.7U/ml, followed by E.coli with 47.9 U/ml and lastly S. cerevisiae with 13.2 U/ml. The localization of the enzyme was also determined. In the methylotrophic yeast, P. Pastoris, the enzyme was secreted into the culture media with little or no contamination from the host proteins, while the in other hosts, the xylanase was located intracellularly. Therefore in this study, a mutated alkaline stable xylanase was successfully expressed in P. Pastoris and was also secreted into the culture medium with little or no contamination by host proteins, which favours the application of this enzyme in the pulp and paper industry. / National Research Foundation

Submitted in complete fulfillment for the Degree of Master of Technology (Biotechnology)in the Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa, 2009. / Protein engineering has been a valuable tool in creating enzyme variants that are capable of withstanding the extreme environments of industrial processes. Xylanases are a family of hemicellulolytic enzymes that are used in the biobleaching of pulp. Using directed evolution, a thermostable and alkaline stabl xylanase variant (S340) was created from the thermophilic fungus, Thermomyces lanuginosus. However, a host that was capable of rapid growth and high-level expression of the enzyme in large amounts was required. The insert containing the xylanase gene was cloned into a series a pET vectors in Escherichia coli BL21 (DE3) pLysS and trimmed from 786 bp to 692 bp to remove excess fungal DNA upstream and downstream of the open reading frame (ORF). The gene was then re-inserted back into the pET vectors. Using optimized growth conditions and lactose induction, a 14.9% increase in xylanase activity from 784.3 nkat/ml to 921.8 nkat/ml was recorded in one of the clones. The increase in expression was most probably due to the removal of fungal DNA between the vector promoter and the start codon. The distribution of the xylanase in the extracellular, periplasmic and cytoplasmic fractions was 17.3%, 51.3% and 31.4%, respectively. The modified enzyme was then purified to electrophoretic homogeneity using affinity chromatography. The xylanase had optimal activity at pH 5.5 and 70°C. After 120 min at 90°C and pH 10, S340 still displayed 39% residual activity. This enzyme is therefore well suited for its application in the pulp and paper industry. / National Research Foundation

Thesis submitted in compliance with the requirements for the Master's Degree in Technology: Industrial Engineering, Department of Industrial Engineering, Durban University of Technology, 2009. / This research focuses on the design and implementation of an intelligent machine vision and sorting system that can be used to sort objects in an industrial environment. Machine vision systems used for sorting are either geometry driven or are based on the textural components of an object’s image. The vision system proposed in this research is based on the textural analysis of pixel content and uses an artificial neural network to perform the recognition task. The neural network has been chosen over other methods such as fuzzy logic and support vector machines because of its relative simplicity. A Bluetooth communication link facilitates the communication between the main computer housing the intelligent recognition system and the remote robot control computer located in a plant environment. Digital images of the workpiece are first compressed before the feature vectors are extracted using principal component analysis. The compressed data containing the feature vectors is transmitted via the Bluetooth channel to the remote control computer for recognition by the neural network. The network performs the recognition function and transmits a control signal to the robot control computer which guides the robot arm to place the object in an allocated position. The performance of the proposed intelligent vision and sorting system is tested under different conditions and the most attractive aspect of the design is its simplicity. The ability of the system to remain relatively immune to noise, its capacity to generalize and its fault tolerance when faced with missing data made the neural network an attractive option over fuzzy logic and support vector machines.

The transformation of the Swedish Armed Forces is bringing about major changes in many areas. Indirect fire is one capability affected by these changes. Financial savings, a shrinking organization and higher eligibility requirements mean that fewer soldiers will gain access to exclusive high-tech support resources such as the JAS 39 Gripen aircraft and the ARCHER artillery system. This thesis aims to examine whether access to indirect fire capability can be increased through the use of civilian products and communication networks. Technology development in the civilian mobile communications area is exponential and nations such as the USA, facing challenges similar to those of the Swedish Armed Forces, devote substantial resources to research and development. Is the use of mobile phones for military purposes the innovation needed by the Swedish Armed Forces, do the necessary technical conditions exist and is the technology applicable during peace and wartime operations? The results indicate that the military use of commercial technology is too low at the moment, but that the technology itself sets no limits, and that there is a need and a demand to develop military mobile apps. The robustness of commercial networks does not meet Armed Forces’ requirements and the Armed Forces need a clear strategy that states the aims and objectives before procurement and implementation is possible. The results show further that, regardless of the challenges identified, there are good reasons to continue to pursue these issues in order to build up experience and knowledge in this area of technology. The development of civil mobile phone technology for military purposes will mean that there is an economically viable resource to use in the future.

Pain is a personal subjective experience with physiological and psychological components and involves many complex processes. In 1965 Melzack and Wall proposed the influential gate control theory (GCT) of pain and, in general, this has been supported by subsequent research. This theory postulates that cells in the substantia gelatinosa, located within the spinal cord, act like a gate mechanism that modulates the flow of information through the spinal cord to the brain and thus impacts on the pain experience. The abundance of literature and experimental data that is available from pain research supports the development and testing of computational models for the simulation and exploration of the pain process. Despite the fact that pain is an ideal candidate for modeling, it is an area that has received little attention. One of the few published models (Britton and Skevington, 1989; Britton et al., 1996) translated the explicitness of the GCT and its well-defined architecture into a basic mathematical model. The aim of this research is to develop a biologically appropriate computational model of pain, capable of modelling both acute and chronic pain states, and describe applications and simulations appropriate to such a model. Therefore this research firstly replicates a mathematical model of pain (Britton and Skevington, 1989; Britton et al., 1996) to explore its adequacy and to assess its potential for further development. The original model is then developed and extended to produce a more biologically plausible representation of the pain processes involved in the Gate Control mechanism. The improvements in the computational model have enabled a clinically plausible simulation of a pain modulatory technique, transcutaneous electrical nerve stimulation (TENS), which validates the model’s representation of the GCT and provides insight into how pain modulation can occur. Other developments to this model show its unique ability to represent symptoms of chronic pain, such as allodynia and hyperalgesia, which are associated with pathological pain states developed through the loss of inhibition and glial cell activation

International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / The purpose of this paper is to describe the Tri-Service effort to use the NAVSTAR Global Positioning System (GPS) on Tri-Service ranges. It will describe the background, the development program, the equipment, the management team, the specifications that the equipment must satisfy, the integration into five DOD ranges, an assessment of developmental risk, a recap of logistical aspects, and will provide a development schedule.