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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Mathematical modeling of the transmission dynamics of malaria in South Sudan

Mukhtar, Abdulaziz Yagoub Abdelrahman January 2019 (has links)
Philosophiae Doctor - PhD / Malaria is a common infection in tropical areas, transmitted between humans through female anopheles mosquito bites as it seeks blood meal to carry out egg production. The infection forms a direct threat to the lives of many people in South Sudan. Reports show that malaria caused a large proportion of morbidity and mortality in the fledgling nation, accounting for 20% to 40% morbidity and 20% to 25% mortality, with the majority of the affected people being children and pregnant mothers. In this thesis, we construct and analyze mathematical models for malaria transmission in South Sudan context incorporating national malaria control strategic plan. In addition, we investigate important factors such as climatic conditions and population mobility that may drive malaria in South Sudan. Furthermore, we study a stochastic version of the deterministic model by introducing a white noise.
142

The classification and framing of the curriculum: a case of integrated studies

Chien, Robyn Kay January 2004 (has links)
This study focuses on curriculum integration for several reasons. Firstly, because there appeared to be no clear definition of integration nor a consensus on what constituted good integration. Secondly, there were few studies on integration and the type of learning involved. I believe that a study looking at an integrated unit in depth should help to shed light on what integration is and how it can be accommodated within the school system. Thirdly, an opportunity existed to observe such a unit within an established middle school. As integration is purported as being "the way" young adolescents should be taught, a middle school setting seemed ideal to me. I thought that this setting should be far enough removed from the content driven senior school to allow for its complete and uninhibited development, especially given the philosophy of this well developed middle school. Fourthly, I am interested in the potential of integration as a way of focusing on learning outcomes rather than curriculum inputs. My own theoretical perspective, with a heavy leaning toward constructivist ideas, caused me to lean towards qualitative rather than quantitative research methodologies and methods. I wanted to do justice to the study by clearly describing the social context of the school and the curriculum. Basil Bemstein's pedagogic code was seen as a way of providing the framework for the development of such a method of description. As this pedagogic code had seldom been used in a study such as this, a complete investigation of its descriptive and analytic power was seen as being of benefit to future curriculum research. The study involved two major tasks. The first task was to develop the framework to a point that it would provide a descriptive language for the recording and analysis of a school culture. / This was done by reconceptualising theories about the sociology of knowledge drawing on research by Bemstein (1971a; 1971b; 1977; 1990; 1996; 2000), Young (1971), Daniels (1987; 1989; 1995; 2001), Morais (1992) and Parker (1994) and modifying the resulting mapping tool developed to suit the complexity of the data gathered. The second task was to apply this framework to the observational data and to derive a description of the culture of the school and the micro-cultures of the two units of study observed within this school. From this description meaning was generated in the form of propositional statements about the development of an integrated unit of study within the culture of a school.
143

Novel framework materials : organically templated silicogermanates and hybrid fluorotitanates

Tang, Liqiu January 2005 (has links)
<p>Two types of novel framework materials, including six organically templated silicogermanates and five hybrid fluorotitanates, have been synthesized, and their structures have been determined by single crystal X-ray diffraction. Their structures and the interactions between the organic and inorganic species are discussed in some detail.</p><p>The frameworks of the six silicogermanates, SU-9, SU-10, SU-11, SU-12, SU-14 and SU-21, are built up from either tetrahedra exclusively, or from mixed polyhedra. SU-9, SU-10 and SU-11 consist only of tetrahedra, and SU-12, SU-14 and SU-21 are built up from mixed polyhedra. In all silicogermanates, Si and Ge share the tetrahedrally coordinated positions, and only Ge occupies the 5- and 6-coordinated positions.</p><p>The frameworks of SU-9, SU-10 and SU-11 belong to zeolite frameworks. SU-9 and SU-10 are built up from the same periodic building units (PBUs) that are formed by 4/4-4 units, and they adopt the known zeolite framework types AST and ASV, respectively. SU-11 is built up from 5-1 units and adopts the known zeolite framework type MFI. This is the first time that the frameworks of AST, ASV and MFI have been prepared in silicogermanate form.</p><p>The 3-D frameworks of SU-12 and SU-14 contain (Ge,Si)<sub>7</sub> composite building units that form one-dimensional 24-ring channels along the <i>c</i> axis. Their structures contain intersecting channels. SU-12 contains 8-, 10- 12- and 24-ring channels; while SU-14 has 9-, 10-, 12- and 24-ring channels. SU-21 is a two-dimensional framework structure containing 10-ring channels. It is the first silicogermanate with the template covalently bonded to Ge.</p><p>All silicogermanates were synthesized by using organic amines as templates. The templates play a very important role in directing the structure of the inorganic framework.</p><p>The obtained five hybrid fluorotitanates are SUF-1, SUF-2, SUF-3, SUF-4 and SUF-5. Their hybrid frameworks are built up from fluorotitanate anions, N-containing cations and crystal water/oxonium cations. Zero-dimensional fluorotitanate clusters are normally obtained when cyclic organic amines such as 1,4-diazabicyclo[2,2,2]octane (DABCO) and piperazine are used. Increasing the pH value of the starting solutions led to more condensed fluorotitanate anions, from isolated octahedra to pairs and eventually chains of octahedra. The formation of the hybrid frameworks of fluorotitanates is strongly dependent on hydrogen bonds between the fluorotitanate anions, N-containing organic cations and water molecules/oxonium ions.</p>
144

An analysis of the DOI framework

Lindelöw, Jonas, Löfberg, Richard January 2006 (has links)
<p>This report describes and evaluates an application development framework called DOI, which is used for building document-oriented applications. A document-oriented application is an application where the user interface promotes a workflow that is tightly coupled to the business objects, instead of for example the functionality (as is the case in function-oriented applications).</p><p>The report provides a brief description of the underlying technologies, Java and Enterprise JavaBeans, followed by a description of the DOI framework. This entails technical descriptions as well as a more general overview of the framework and associated tools. There is also a more detailed description of how to create an application provided in an appendix.</p><p>In the evaluation phase we consider the following attributes: usability, extensibility, code quality and developing time. After taking into consideration how the different parts of the framework affect these attributes we conclude that DOI is a usable and extensible framework, which should contribute a great deal in the development process for applications belonging to the domain of applications targeted by the framework.</p>
145

A Unified Statistical and Information Theoretic Framework for Multi-modal Image Registration

Zollei, Lilla, Fisher, John, Wells, William 28 April 2004 (has links)
We formulate and interpret several multi-modal registration methods in the context of a unified statistical and information theoretic framework. A unified interpretation clarifies the implicit assumptions of each method yielding a better understanding of their relative strengths and weaknesses. Additionally, we discuss a generative statistical model from which we derive a novel analysis tool, the "auto-information function", as a means of assessing and exploiting the common spatial dependencies inherent in multi-modal imagery. We analytically derive useful properties of the "auto-information" as well as verify them empirically on multi-modal imagery. Among the useful aspects of the "auto-information function" is that it can be computed from imaging modalities independently and it allows one to decompose the search space of registration problems.
146

Analysis of powder compaction process through equal channel angular extrusion

Kaushik, Anshul 15 May 2009 (has links)
A thermodynamic framework was presented for the development of powderconstitutive models. The process of powder compaction through Equal ChannelAngular Extrusion (ECAE) at room temperature was modeled using the finiteelement analysis package ABAQUS. The simulation setup was used to conduct aparametric study involving varying the process parameters of ECAE, aimed ataiding the process design.Two powder compaction models, the Gurson model and the Duva and Crowmodel, were used to test their efficacy in modeling this process. Thethermodynamic framework was applied to derive the constitutive equations of theDuva and Crow model. Modeling parameters like friction coefficients, interactionconditions were determined by comparing the simulations for solid billet and anempty can with actual experimental runs for loads, shear angle and workpiece geometry. The simulations using the two powder constitutive models showed nosignificant difference in the stress in the powder during the extrusion.The results obtained from the 3-D simulations were also compared toexperiments conducted to compact copper powder with a size distribution of 10mto 45m. It was found through experiments that the powder does not fullyconsolidate near the outer corner of the workpiece after the first ECAE pass and theresults from the simulations were used to rationalize this phenomenon.Modifications made to the process by applying a back pressure during thesimulations resulted in a uniformly compacted powder region.Further, simulations were carried out by varying the process parameters likethe crosshead velocity, the friction coefficient between the walls of the die and thecan, can dimensions and material, shape of the can cross section etc and the effectof each of these parameters was quantified by doing a sensitivity analysis.
147

Novel framework materials : organically templated silicogermanates and hybrid fluorotitanates

Tang, Liqiu January 2005 (has links)
Two types of novel framework materials, including six organically templated silicogermanates and five hybrid fluorotitanates, have been synthesized, and their structures have been determined by single crystal X-ray diffraction. Their structures and the interactions between the organic and inorganic species are discussed in some detail. The frameworks of the six silicogermanates, SU-9, SU-10, SU-11, SU-12, SU-14 and SU-21, are built up from either tetrahedra exclusively, or from mixed polyhedra. SU-9, SU-10 and SU-11 consist only of tetrahedra, and SU-12, SU-14 and SU-21 are built up from mixed polyhedra. In all silicogermanates, Si and Ge share the tetrahedrally coordinated positions, and only Ge occupies the 5- and 6-coordinated positions. The frameworks of SU-9, SU-10 and SU-11 belong to zeolite frameworks. SU-9 and SU-10 are built up from the same periodic building units (PBUs) that are formed by 4/4-4 units, and they adopt the known zeolite framework types AST and ASV, respectively. SU-11 is built up from 5-1 units and adopts the known zeolite framework type MFI. This is the first time that the frameworks of AST, ASV and MFI have been prepared in silicogermanate form. The 3-D frameworks of SU-12 and SU-14 contain (Ge,Si)7 composite building units that form one-dimensional 24-ring channels along the c axis. Their structures contain intersecting channels. SU-12 contains 8-, 10- 12- and 24-ring channels; while SU-14 has 9-, 10-, 12- and 24-ring channels. SU-21 is a two-dimensional framework structure containing 10-ring channels. It is the first silicogermanate with the template covalently bonded to Ge. All silicogermanates were synthesized by using organic amines as templates. The templates play a very important role in directing the structure of the inorganic framework. The obtained five hybrid fluorotitanates are SUF-1, SUF-2, SUF-3, SUF-4 and SUF-5. Their hybrid frameworks are built up from fluorotitanate anions, N-containing cations and crystal water/oxonium cations. Zero-dimensional fluorotitanate clusters are normally obtained when cyclic organic amines such as 1,4-diazabicyclo[2,2,2]octane (DABCO) and piperazine are used. Increasing the pH value of the starting solutions led to more condensed fluorotitanate anions, from isolated octahedra to pairs and eventually chains of octahedra. The formation of the hybrid frameworks of fluorotitanates is strongly dependent on hydrogen bonds between the fluorotitanate anions, N-containing organic cations and water molecules/oxonium ions.
148

A Framework for Assessing National Tourism Plans

Ibrahim, Zainub January 2013 (has links)
An integrated framework is created to assess national-level tourism plans and is applied to the Egyptian case. To date, the assessment of tourism planning has been a tedious, expensive process and detailed evaluations have not often been undertaken in a systematic manner. It is argued that much can be learned about tourism planning by examining tourism planning documents systematically according to a set of criteria. Although plans differ depending on their contexts, there are certain attributes that should be present in all tourism plans. In this dissertation a set of characteristics is delineated that should be present in national-level tourism plans. The proposed assessment framework is divided into four major components: goals and objectives, approach to tourism planning, institutional elements, and marketing. Each component is then further divided into key points drawn from pertinent literatures that suggest the characteristics of a good plan and, therefore, what should be assessed in plan evaluation. The framework is then applied to the Egyptian tourism plan to guide an examination and assessment of the documents. Based on this analysis, recommendations are made to improve Egyptian tourism planning. This research contributes to tourism planning by suggesting a framework that can be employed with relative ease to assess tourism plans for different national-level destinations, thus facilitating problem and issue identification, offering an opportunity for learning, and providing a structure for undertaking comparative studies.
149

Exploring Learning Experiences and Outcomes among Cardiologists Participating in a Web Conference Workshop Series

Pullen, Carolyn 06 November 2012 (has links)
Opportunities for supporting physician continuing professional development (CPD) may exist through careful instructional design and creative use of information and communication technology. The overarching goal of this study was to explore the learning experiences and outcomes of cardiologists participating in a web conference (“webinar”) series to understand the factors that can support webinars in being an appealing and satisfying CPD medium for these learners. Acknowledging that a pedagogically-based framework for program design is a cornerstone of effective CPD (Hutchinson & Estabrooks, 2009; Inan & Lowther, 2007; Casimiro, MacDonald, Thompson, & Stodel, 2009), this study used the W(e)Learn Framework (MacDonald, Stodel, Thompson, & Casimiro, 2009) as a process guide and quality standard for program design, development and delivery. Cardiologists voluntarily participated in an educational webinar series in which they shared their observations and experiences. Informed by the results of a systematic review of physician eLearning design preferences, this dissertation serves as a mechanism to learn about how webinars can be implemented to support learning and practice change within a population of highly specialized physician learners. Methodological approaches included a systematic review of literature examining physician preferences for eLearning design, a case study of webinar implementation, and interviews with cardiologists who participated in the webinars. The findings of the systematic review, the case study and the interviews aligned to characterize key considerations in webinar implementation. Webinar designers must carefully determine program structures, content, and media to create a satisfying learning experience. Cardiologists seek a webinar experience that responds to their professional reality of competing priorities, complex patients, and ambiguous clinical questions. They seek a mix of evidence-based, authentic and challenging content, delivered by credible content experts. The study found that purposefully designed webinars can be a satisfying learning experience for cardiologists with the potential to influence changes in knowledge and practice. The use of an instructional design framework may structure and enrich webinar implementation; this dissertation encourages their use.
150

DescribeX: A Framework for Exploring and Querying XML Web Collections

Rizzolo, Flavio Carlos 26 February 2009 (has links)
The nature of semistructured data in web collections is evolving. Even when XML web documents are valid with regard to a schema, the actual structure of such documents exhibits significant variations across collections for several reasons: an XML schema may be very lax (e.g., to accommodate the flexibility needed to represent collections of documents in RSS feeds), a schema may be large and different subsets used for different documents (e.g., this is common in industry standards like UBL), or open content models may allow arbitrary schemas to be mixed (e.g., RSS extensions like those used for podcasting). A schema alone may not provide sufficient information for many data management tasks that require knowledge of the actual structure of the collection. Web applications (such as processing RSS feeds or web service messages) rely on XPath-based data manipulation tools. Web developers need to use XPath queries effectively on increasingly larger web collections containing hundreds of thousands of XML documents. Even when tasks only need to deal with a single document at a time, developers benefit from understanding the behaviour of XPath expressions across multiple documents (e.g., what will a query return when run over the thousands of hourly feeds collected during the last few months?). Dealing with the (highly variable) structure of such web collections poses additional challenges. This thesis introduces DescribeX, a powerful framework that is capable of describing arbitrarily complex XML summaries of web collections, providing support for more efficient evaluation of XPath workloads. DescribeX permits the declarative description of document structure using all axes and language constructs in XPath, and generalizes many of the XML indexing and summarization approaches in the literature. DescribeX supports the construction of heterogenous summaries where different document elements sharing a common structure can be declaratively defined and refined by means of path regular expressions on axes, or axis path regular expression (AxPREs). DescribeX can significantly help in the understanding of both the structure of complex, heterogeneous XML collections and the behaviour of XPath queries evaluated on them. Experimental results demonstrate the scalability of DescribeX summary refinements and stabilizations (the key enablers for tailoring summaries) with multi-gigabyte web collections. A comparative study suggests that using a DescribeX summary created from a given workload can produce query evaluation times orders of magnitude better than using existing summaries. DescribeX’s light-weight approach of combining summaries with a file-at-a-time XPath processor can be a very competitive alternative, in terms of performance, to conventional fully-fledged XML query engines that provide DB-like functionality such as security, transaction processing, and native storage.

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