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Dissertations / Theses on the topic 'Research methods'
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1
Wood, David L. "Research Methods Overview." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/5173.
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Faxälv, Lars. "Imaging methods for haemostasis research." Doctoral thesis, Linköpings universitet, Klinisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19178.
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Blood is a vital part of the human physiology; a transport system that brings nutrients and oxygen to sustain living cells and simultaneously facilitates the removal of carbon dioxide and other waste products from the body. To assure the continuity of these functions, it is of uttermost importance to keep the flowing blood inside the vascular system at any cost. The principal components of the haemostatic system are the blood platelets and the plasma coagulation system, both working in concert to create a blood stopping haemostatic plug when a vessel is ruptured. In modern health care, methods for treatment and diagnostics often implicate the contact between blood and artificial materials (biomaterials). Biomaterial surfaces may activate platelets and the coagulation cascade by exposing a surface that during blood contact shares certain characteristics with surfaces found at the site of vascular injury. Therefore it is of great importance that the mechanisms behind the interactions between foreign surfaces and blood are studied in order to minimize, and if possible, prevent unnecessary reactions that may lead to thrombosis. This thesis describes two important methods to study blood – surface interactions in terms of surface induced plasma coagulation and platelet adhesion/aggregation. The method ‘Imaging of coagulation’, a coagulation assay based on time-lapse image capture of the coagulation process was developed during the course of this work. The use of images enables the method to answer questions regarding where coagulation was initiated and how fast coagulation propagates. Such questions are highly relevant in the study of blood-biomaterial interactions but also in general haemostasis research. In vivo, platelet adhesion and aggregation are events that always proceed under flow conditions. Therefore we also developed a cone-and-plate flow model to study these mechanisms under similar conditions in vitro. The cone-and-plate setup was found to be a flexible platform and was used for both blood compatibility testing of potential biomaterials as well as for general haemostasis research. With the above mentioned methods we tested the haemocompatibility of glycerol monooleate (GMO), a proposed substance for use in biomaterial applications. It was found that GMO did not activate coagulation to any great extent either in plasma or in whole blood. Surface induced coagulation and platelet adhesion was also studied on PEG-containing hydrogels and compared with hydrogels constructed from three different non-PEG-containing monomers. It was concluded that all the grafted hydrogels, in particular those produced from the monomers 2-hydroxyethyl methacrylate (HEMA) and/or PEG- methacrylate (PEGMA), demonstrated good haemocompatibility. Supported phospholipid bilayers were used to investigate the relationship between surface charge and procoagulant activity. The coagulation process was studied in a straightforward manner using the imaging of coagulation setup. We concluded that the content of negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-L-serine] (POPS) in the bilayer must exceed ~ 6% for the bilayer to exert procoagulant activity. The physiological role of factor XII in human haemostasis and thrombosis was investigated in the imaging of coagulation setup and the cone and plate setup by the use of surfaces with thrombogenic coatings. We found that tissue factor initiated coagulation could be greatly accelerated by the presence of contact activating agents in a platelet dependent manner. In conclusion, the method ‘Imaging of coagulation’ and platelet adhesion/aggregation in the cone-and-plate flow model are both versatile methods with many possible applications. The combination of the two methods provides a solid foundation for biomaterial and haemostasis research.
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Hill, Brian Joseph. "Textile research : methods and applications." Thesis, University of Ulster, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339310.
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Grinko, N. V. "Community-based participatory research methods." Thesis, БДМУ, 2022. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18974.
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Tolley, Rebecca. "Sage Research Methods Online [workshop]." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/5753.
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Knutson, Anna V., and Merideth Garcia. "Ethics in Digital Research Methods." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/5449.
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Sandgren, Niclas. "Parametric methods for frequency-selective MR spectroscopy /." Uppsala : Univ. : Dept. of Information Technology, Univ, 2004. http://www.it.uu.se/research/reports/lic/2004-001/.
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Desjardins, Pat. "Theories and methods in feminist research." Thesis, University of Essex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280813.
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Vanchuliak, O., V. T. Bachinskiy, and Y. Sarkisova. "Latest prospective polarizational methods of research." Thesis, Abstracts of international scientific conference “Modern advances in forensic science and expertise” Uzhgorod, 2015, 2015. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/11258.
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Fronza, Raffaele <1971>. "Bioinformatic methods in applied genomic research." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3567/1/fronza_raffaele_tesi.pdf.
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Here I will focus on three main topics that best address and include the projects I have been working in during my three year PhD period that I have spent in different research laboratories addressing both computationally and practically important problems all related to modern molecular genomics.
The first topic is the use of livestock species (pigs) as a model of obesity, a complex human dysfunction. My efforts here concern the detection and annotation of Single Nucleotide Polymorphisms. I developed a pipeline for mining human and porcine sequences. Starting from a set of human genes related with obesity the platform returns a list of annotated porcine SNPs extracted from a new set of potential obesity-genes. 565 of these SNPs were analyzed on an Illumina chip to test the involvement in obesity on a population composed by more than 500 pigs. Results will be discussed. All the computational analysis and experiments were done in collaboration with the Biocomputing group and Dr.Luca Fontanesi, respectively, under the direction of prof. Rita Casadio at the Bologna University, Italy.
The second topic concerns developing a methodology, based on Factor Analysis, to simultaneously mine information from different levels of biological organization. With specific test cases we develop models of the complexity of the mRNA-miRNA molecular interaction in brain tumors measured indirectly by microarray and quantitative PCR. This work was done under the supervision of Prof. Christine Nardini, at the “CAS-MPG Partner Institute for Computational Biology” of Shangai, China (co-founded by the Max Planck Society and the Chinese Academy of Sciences jointly)
The third topic concerns the development of a new method to overcome the variety of PCR technologies routinely adopted to characterize unknown flanking DNA regions of a viral integration locus of the human genome after clinical gene therapy. This new method is entirely based on next generation sequencing and it reduces the time required to detect insertion sites, decreasing the complexity of the procedure. This work was done in collaboration with the group of Dr. Manfred Schmidt at the Nationales Centrum für Tumorerkrankungen (Heidelberg, Germany) supervised by Dr. Annette Deichmann and Dr. Ali Nowrouzi.
Furthermore I add as an Appendix the description of a R package for gene network reconstruction that I helped to develop for scientific usage (http://www.bioconductor.org/help/bioc-views/release/bioc/html/BUS.html).
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Fronza, Raffaele <1971>. "Bioinformatic methods in applied genomic research." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3567/.
Full textAbstract:
Here I will focus on three main topics that best address and include the projects I have been working in during my three year PhD period that I have spent in different research laboratories addressing both computationally and practically important problems all related to modern molecular genomics.
The first topic is the use of livestock species (pigs) as a model of obesity, a complex human dysfunction. My efforts here concern the detection and annotation of Single Nucleotide Polymorphisms. I developed a pipeline for mining human and porcine sequences. Starting from a set of human genes related with obesity the platform returns a list of annotated porcine SNPs extracted from a new set of potential obesity-genes. 565 of these SNPs were analyzed on an Illumina chip to test the involvement in obesity on a population composed by more than 500 pigs. Results will be discussed. All the computational analysis and experiments were done in collaboration with the Biocomputing group and Dr.Luca Fontanesi, respectively, under the direction of prof. Rita Casadio at the Bologna University, Italy.
The second topic concerns developing a methodology, based on Factor Analysis, to simultaneously mine information from different levels of biological organization. With specific test cases we develop models of the complexity of the mRNA-miRNA molecular interaction in brain tumors measured indirectly by microarray and quantitative PCR. This work was done under the supervision of Prof. Christine Nardini, at the “CAS-MPG Partner Institute for Computational Biology” of Shangai, China (co-founded by the Max Planck Society and the Chinese Academy of Sciences jointly)
The third topic concerns the development of a new method to overcome the variety of PCR technologies routinely adopted to characterize unknown flanking DNA regions of a viral integration locus of the human genome after clinical gene therapy. This new method is entirely based on next generation sequencing and it reduces the time required to detect insertion sites, decreasing the complexity of the procedure. This work was done in collaboration with the group of Dr. Manfred Schmidt at the Nationales Centrum für Tumorerkrankungen (Heidelberg, Germany) supervised by Dr. Annette Deichmann and Dr. Ali Nowrouzi.
Furthermore I add as an Appendix the description of a R package for gene network reconstruction that I helped to develop for scientific usage (http://www.bioconductor.org/help/bioc-views/release/bioc/html/BUS.html).
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Rolland, Erik. "Abstract heuristic search methods for graph partitioning." Connect to resource, 1991. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1262633923.
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Rönkkö, Kari. "Making Methods Work in Software Engineering : Method Deployment - as a Social Achievement." Doctoral thesis, Ronneby : Blekinge Institute of Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00264.
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The software engineering community is concerned with improvements in existing methods and development of new and better methods. The research approaches applied to take on this challenge have hitherto focused heavily on the formal and specifying aspect of the method. This has been done for good reasons, because formalizations are the means in software projects to predict, plan, and regulate the development efforts. As formalizations have been successfully developed new challenges have been recognized. The human and social role in software development has been identified as the next area that needs to be addressed. Organizational problems need to be solved if continued progress is to be made in the field. The social element is today a little explored area in software engineering. Following with the increased interest in the social element it has been identified a need of new research approaches suitable for the study of human behaviour. The one sided focus on formalizations has had the consequence that concepts and explanation models available in the community are one sided related in method discourses. Definition of method is little explored in the software engineering community. In relation to identified definitions of method the social appears to blurring. Today the software engineering community lacks powerful concepts and explanation models explaining the social element. This thesis approaches the understanding of the social element in software engineering by applying ethnomethodologically informed ethnography and ethnography. It is demonstrated how the ethnographic inquiry contributes to software engineering. Ethnography is also combined with an industrial cooperative method development approach. The results presented demonstrate how industrial external and internal socio political contingencies both hindered a method implementation, as well as solved what the method was targeted to do. It is also presented how project members’ method deployment - as a social achievement is played out in practice. In relation to this latter contribution it is provided a conceptual apparatus and explanation model borrowed from social science, The Documentary method of interpretation. This model addresses core features in the social element from a natural language point of view that is of importance in method engineering. This model provides a coherent complement to an existing method definition emphasizing formalizations. This explanation model has also constituted the underpinning in research methodology that made possible the concrete study results.
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Hong, Mei. "On two methods for identifying dynamic errors-in-variables systems." Licentiate thesis, Uppsala : Department of Information Technology, Uppsala University, 2005. http://www.it.uu.se/research/reports/lic/2005-007/.
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Bängtsson, Erik. "Robust preconditioned iterative solution methods for large-scale nonsymmetric problems /." Uppsala : Department of Information Technology, Uppsala University, 2005. http://www.it.uu.se/research/reports/lic/2005-006/.
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Neequaye, Beryl Koteikor. "Reviewing the Quality of Mixed Methods Research Reporting in Comparative and International Education: A Mixed Methods Research Synthesis." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565886346044592.
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Lukin, Galit. "Prescriptive methods for adaptive learning." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127293.
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Thesis: S.M., Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, May, 2020Cataloged from PDF version of thesis.
Includes bibliographical references (pages 53-54).
It is undeniable that recent world events and globalization have transformed online learning into one of the main channels for education. Online learning has become a necessity, not a luxury. Universities, schools, and pre-schools have transformed into the online learning space holding classes of hundreds of students concurrently. However, online learning has yet to reach its full potential. Although educators understand the benefits and effectiveness of online learning platforms, the lack of engagement and evaluation are clear. None the less, these challenges can be solved through machine learning. In this thesis, we present novel, interpretable prescriptive methods to the online learning setting. We apply these techniques to adaptive learning and test them in real online course settings. We show that using an interpretable, optimal tree-based approach improves both the engagement and the learning rates of the learners. We present PLOpt, a full-stack web app that leverages machine learning models and learner, content knowledge to create assignments that best suit each individual learner. We describe the models, how they were tested, and their evaluation. We demonstrate that by using PLOpt, learners achieved higher engagement and proficiency levels. In addition, we show how PLOpt created assignments that matched the correct difficulty level of the learners so that the learner could remain engaged with challenging questions, yet not frustrated by questions too difficult to answer. Altogether, this work demonstrates that applying interpretable machine learning to online learning builds personalized learning platforms and solves the challenges raised in today's online learning world.
by Galit Lukin.
S.M.
S.M. Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center
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Bwanika, Daniel. "Realistic Theory as Methods for Scientific Research." Thesis, Örebro University, School of Humanities, Education and Social Sciences, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-6327.
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楊謹鴻 and Kim-fong Roseline Yong. "Exploring hikikomori: a mixed methods qualitative research." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41712146.
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Corrado, Charles J. "Nonparametric statistical methods in financial market research." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184608.
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This dissertation presents an exploration of the use of nonparametric statistical methods based on ranks for use in financial market research. Applications to event study methodology and the estimation of security systematic risk are analyzed using a simulation methodology with actual daily security return data. The results indicate that procedures based on ranks are more efficient than normal theory procedures currently in common use.
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Cheng, Xiao Liang. "Some research on mixed finite element methods." HKBU Institutional Repository, 1995. http://repository.hkbu.edu.hk/etd_ra/48.
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Yong, Kim-fong Roseline. "Exploring hikikomori a mixed methods qualitative research /." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41712146.
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Chiu, Jing-Er. "Applications of bayesian methods to arthritis research /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036813.
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Hines, Sonia J. "Nurses' research literacy: A multi-methods exploration." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/229970/1/Sonia_Hines_Thesis.pdf.
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This thesis explored the concept of nurses' research literacy – how nurses' read and understand research literature. Through two systematic reviews of the literature, a pilot study and a qualitative research study, insights were formed into how nurses perceive research and how improved research literacy could be facilitated. Forty registered nurses from around Australia shared their experiences of learning about, reading and using research which led to different ways of thinking about teaching research. A new intervention for increasing research literacy, using a language-based, genre-analysis approach, was developed and found to be feasible and effective.
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Zago, M. "RESEARCH METHODS IN SPORTS AND CLINICAL BIOMECHANICS." Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/352554.
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Within sports and health sciences, the biomechanical study of human movement has many purposes, including rehabilitation, injury prevention and performance analysis. While in clinical biomechanics the main goal is to determine if a motion is physiological or if it differs from normal values, in the sports context the aim is finding the movement determinants that allows an athlete to perform at the highest possible level.
Research in movement analysis is nowadays supported by multi-camera stereophotogrammetric systems, used to reconstruct three-dimensional body landmarks coordinates from video images. These allow the collection of quantitative information about the mechanics of the musculo-skeletal system during the execution of a motor task. In particular, the following quantities will be considered: the kinematics of the whole-body centre of mass (CoM); the relative movement between adjacent bones (joint kinematics); body segment energy variation and muscular work.
The current thesis contains the main experimental projects of my doctoral research activity. Many performance analyses were based on the estimation of the kinematics of the body CoM, whose reliability was demonstrated with a reduced marker set, which is desirable when dealing with complex movements. Inspecting CoM kinematics gives the researcher a complete view of the athletes’ movements, with a insight on balance and motor control: we found that expert karateka, who are supposed to possess superior balance abilities, perform the same fighting sequence with a lower CoM as compared with amateur practitioners. We also found that the strategy adopted by young soccer players to be faster in a slalom dribbling task consists in the optimization of CoM path throughout the course, i.e. in a more sophisticated motor control.
The inspection of joint kinematics allows to assess the functioning of kinetic chains, i.e. proximal-to-distal linkage between segments, and to understand the phases of complex multi-segmental techniques: in soccer pass-kick we identified laterality-driven differences between the preferred and non-preferred side. Kinematic curves, as well as gait cycle parameters like step width, length or cadence, helped in identifying locomotion issues in a patient wearing a knee endoprosthesis.
An emerging and stimulating challenge in motion analysis is the extraction of distinct features from the large amount of available kinematic data: two are symmetry and variability. Symmetry indexes were applied to assess the effects of a physiotherapy intervention on a prosthetic patient, while a novel repeatability index was developed for mandibular joint motion. Additionally, multivariate statistical techniques like the Principal Components Analysis allowed for the identification of abnormal gait patterns in urologic patients, as well as for the extraction of fundamental motor modules from complex sports skill in soccer and elite karate athletes.
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Chang, Allison An. "Integer optimization methods for machine learning." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72643.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 129-137).
In this thesis, we propose new mixed integer optimization (MIO) methods to ad- dress problems in machine learning. The first part develops methods for supervised bipartite ranking, which arises in prioritization tasks in diverse domains such as information retrieval, recommender systems, natural language processing, bioinformatics, and preventative maintenance. The primary advantage of using MIO for ranking is that it allows for direct optimization of ranking quality measures, as opposed to current state-of-the-art algorithms that use heuristic loss functions. We demonstrate using a number of datasets that our approach can outperform other ranking methods. The second part of the thesis focuses on reverse-engineering ranking models. This is an application of a more general ranking problem than the bipartite case. Quality rankings affect business for many organizations, and knowing the ranking models would allow these organizations to better understand the standards by which their products are judged and help them to create higher quality products. We introduce an MIO method for reverse-engineering such models and demonstrate its performance in a case-study with real data from a major ratings company. We also devise an approach to find the most cost-effective way to increase the rank of a certain product. In the final part of the thesis, we develop MIO methods to first generate association rules and then use the rules to build an interpretable classifier in the form of a decision list, which is an ordered list of rules. These are both combinatorially challenging problems because even a small dataset may yield a large number of rules and a small set of rules may correspond to many different orderings. We show how to use MIO to mine useful rules, as well as to construct a classifier from them. We present results in terms of both classification accuracy and interpretability for a variety of datasets.
by Allison An Chang.
Ph.D.
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Liebenberg, Linda. "The use of visual research methods in the South African research context." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50532.
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Thesis (DPhil)--Stellenbosch University, 2005.ENGLISH ABSTRACT: South African society presents a complex and diverse environment to social scientists. Within immense economic stratification; a multitude of cultures and classes; languages and their dialects; and varied racial groups, researchers attempt to produce information that contributes constructively to policy, programs and a host of services. Beneath the surface also lay complex power issues informed by both political and cultural histories. Many contexts in which researchers find themselves continue to be marginalised and oppressed due to factors such as illiteracy and low-levels of education, age, gender and poverty. These groups often include women and children, in particular adolescents. Qualitative visual methods may provide researchers with a tool by which to address many of the concerns raised in the literature surrounding research carried out under such conditions. Visual methods may remove inherent power imbalances, as well as traditional barriers, such as culture and language, that stem from more 'conservative' research methods. Images may allow participants to vocalise the taken-for-granted in their lives in an empowering manner. The recognition and use of visual images in research with marginalised and oppressed groups is being increasingly recognised by the larger research community. A preliminary overview of the available literature highlights existing disagreement surrounding the theoretical underpinnings of visual methods. This is particularly seen in the various and confusing levels of abstraction presented in the literature. The primary aim of this study is therefore, to gain clarity and understanding as regards the methodological and epistemological underpinnings of visual research methods within the social sciences. As such, a comprehensive literature review has been conducted. A second aim of the study is to set out a typology of methods that would be relevant for use in marginalised communities. The third aim of the study is empirical in nature and aims to highlight the role and/or possibilities of visual research methods within the South African social sciences research context. This is achieved by means of a case study which explores how motherhood is experienced by five teenagers in a sub-economic community outside of Cape Town. It does this by providing participants cameras with which to visually express their understanding and experiences of motherhood. Processed photographs in this case study have been analysed by means of informal discussion, directed by the images, with the participants themselves. These discussions were recorded and transcribed. The results of the interviews were then analysed using grounded theory (Glaser & Strauss, 1967). The results emerging from this have been compared with relevant literature. In this way, results are also triangulated, adding to their reliability (Lucchinni, 1996). Consequently, results of this case study provide a comparative component by which to assess the applicability of visual methods in the South African research context. Both the literature review as well as experiences of the case study also form the basis of suggestions for further exploration.
AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse gemeenskap bied 'n komplekse en diverse omgewing aan sosiale wetenskaplikes. Binne hewige ekonomiese stratifikasie; 'n verskeidenheid kulture en klasse; tale en dialekte en diverse rassegroepe, poog navorsers om inligting te verskaf om 'n konstruktiewe bydrae te maak aan riglyne, programme en 'n legio dienste. Onder die oppervlakte lê daar ook komplekse magstryde afkomstig van beide 'n kuitereie en politieke geskiedenis. Vele omstandighede waarin navorsers hulself vind word steeds oorheers deur marginalisasie en onderdrukking as gevolg van faktore soos ongeletterdheid, lae vlakke van opvoeding, ouderdom, geslag en armoede. Hierdie groepe bestaan dikwels uit, onder andere, vroue en kinders. Kwalitatiewe visuele tegnieke mag navorsers van die nodige metodes voorsien waarmee verskeie probleme wat in die literatuur uitgelig word aangaande hierdie navorsing, aangespreek kan word. Visuele tegnieke mag inherente magsongelykhede, sowel as tradisionele struikelblokke, soos kultuur en taal wat afkomstig is uit meer 'konserwatiewe' navorsingstegnieke, verwyder. Uitbeeldings mag deelnemers toelaat om die vanselfsprekende in hullewens in 'n opbouende wyse te vokaliseer. Die identifisering en gebruik van visuele uitbeeldings in navorsing met gemarganaliseerde en onderdrukte groepe word tot 'n toenemende mate erken deur die uitgebreide navorsingsgemeenskap. 'n Voorlopige oorsig van die beskikbare literatuur beklemtoon bestaande onenigheid met betrekking tot die teoretiese fondamente van visuele tegnieke. Dit is veral duidelik sigbaar in die uitgebreide en verwarde vlakke van abstraktheid wat in die literatuur voorgestel word. Die primêre doelwit van hierdie studie is dus om groter helderheid en insig met betrekking tot die metodologiese en epistemologiese grondbeginsels van visuele metodes, soos dit in die sosiale wetenskappe voorkom, te verkry. Met hierdie doel voor oë is 'n uitgebreide literatuurondersoek onderneem. 'n Tweede doel van die studie is om 'n tipologie van metodes uiteen te sit wat relevant kan wees in gemarginaliseerde gemeenskappe. 'n Derde doel van die studie is empiries van aard en beoog om die rol en/of moontlikhede van visuele tegnieke binne die Suid-Afrikaanse sosiale wetenskaplike navorsings konteks te beklemtoon. Dit word bereik deur middel van 'n studie wat ondersoek hoe moederskap ondervind word deur vyf tieners in 'n sub-ekonomiese gemeenskap in die buitewyke van Kaapstad. Dit word uitgevoer deur deelnemers te voorsien van kameras waarmee hul begrip en ondervindings van moederskap visueel uitbeeld. 'n Verdere analise van hierdie studie is deur middel van informele besprekings uitgevoer met die deelnemers, begelei deur die uitbeeldings. Sodanige besprekings is opgeneem en getranskribeer. Die resultate verkry vanuit die onderhoude is daarna geanaliseer deur middel van begronde teorie (Glaser & Strauss, 1967). Die resultate wat hieruit afkomstig was, is vergelyk met relevante literatuur. Op hierdie wyse is resultate bevestig, wat ook verder tot hul betroubaarheid gespreek het (Lucchinni, 1996). Die gevolg is dat die resultate van hierdie studie 'n vergelykende komponent verskaf waarmee die toepaslikheid van visuele tegnieke in die Suid-Afrikaanse navorsingskonteks gemeet kan word. Beide die literatuurstudie, asook die ondervindings vanuit die gevallestudie vorm die basis vir aanbevelings vir verdere ondersoek.
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Engblom, Stefan. "Numerical methods for the chemical master equation." Licentiate thesis, Uppsala : Univ. : Dept. of Information Technology, Univ, 2006. http://www.it.uu.se/research/publications/lic/2006-007/2006-007.pdf.
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Vähänikkilä, H. (Hannu). "Statistical methods in dental research, with special reference to time-to-event methods." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207933.
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Abstract Statistical methods are an essential part of the published dental research. It is important to evaluate the use of these methods to improve the quality of dental research. In the first part, the aim of this interdisciplinary study is to investigate the development of the use of statistical methods in dental journals, quality of statistical reporting and reporting of statistical techniques and results in dental research papers, with special reference to time-to-event methods. In the second part, the focus is specifically on time-to-event methods, and the aim is to demonstrate the strength of time-to-event methods in collecting detailed data about the development of oral health. The first part of this study is based on an evaluation of dental articles from five dental journals. The second part of the study is based on empirical data from 28 municipal health centres in order to study variations in the survival of tooth health. There were different profiles in the statistical content among the journals. The quality of statistical reporting was quite low in the journals. The use of time-to-event methods has increased from 1996 to 2007 in the evaluated dental journals. However, the benefits of these methods have not been fully adopted in dental research. The current study added new information regarding the status of statistical methods in dental research. Our study also showed that complex time-to-event analysis methods can be utilized even with detailed information on each tooth in large groups of study subjects. Authors of dental articles might apply the results of this study to improve the study protocol/planning as well as the statistical section of their research articleTiivistelmä Tilastolliset tutkimusmenetelmät ovat olennainen osa hammaslääketieteellistä tutkimusta. Menetelmien käyttöä on tärkeä tutkia, jotta hammaslääketieteen tutkimuksen laatua voitaisiin parantaa. Tämän poikkitieteellisen tutkimuksen ensimmäisessä osassa tavoite on tutkia erilaisten tilastomenetelmien ja tutkimusasetelmien käyttöä, raportoinnin laatua ja tapahtumaan kuluvan ajan analysointimenetelmien käyttöä hammaslääketieteellisissä artikkeleissa. Toisessa osassa osoitetaan analysointimenetelmien vahvuus isojen tutkimusjoukkojen analysoinnissa. Ensimmäisen osan tutkimusaineiston muodostavat viiden hammaslääketieteellisen aikakauslehden artikkelit. Toisen osan tutkimusaineiston muodostivat 28 terveyskeskuksessa eri puolella Suomea hammashoitoa saaneet potilaat. Lehdet erosivat toisistaan tilastomenetelmien käytön ja tulosten esittämisen osalta. Tilastollisen raportoinnin laatu oli lehdissä puutteellinen. Tapahtumaan kuluvan ajan analysointimenetelmien käyttö on lisääntynyt vuosien 1996–2007 aikana. Tapahtumaan kuluvan ajan analysointimenetelmät mittaavat seuranta-ajan tietystä aloituspisteestä määriteltyyn päätepisteeseen. Tämän väitöksen tutkimukset osoittivat, että tapahtumaan kuluvan ajan analysointimenetelmät sopivat hyvin isojen tutkimusjoukkojen analysointiin. Menetelmien hyötyä ei ole kuitenkaan vielä saatu täysin esille hammaslääketieteellisissä julkaisuissa. Tämä tutkimus antoi uutta tietoa tilastollisten tutkimusmenetelmien käytöstä hammaslääketieteellisessä tutkimuksessa. Artikkelien kirjoittajat voivat hyödyntää tämän tutkimuksen tuloksia suunnitellessaan hammaslääketieteellistä tutkimusta
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Marks, Christopher E. (Christopher Edward). "Analytic search methods in online social networks." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112012.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 175-185).
This thesis presents and evaluates methods for searching and analyzing social media data in order to improve situational awareness. We begin by proposing a method for network vertex search that looks for the target vertex by sequentially examining the neighbors of a set of "known" vertices. Using a dynamic programming approach, we show that there is always an optimal "block" search policy, in which all of the neighbors of a known vertex are examined before moving on to another vertex. We provide a precise characterization of the optimal policy in two specific cases: (1) when the connections between the known vertices and the target vertex are independent, and (2) when the target vertex is connected to at most one known vertex. We then apply this result to the problem of finding new accounts belonging to Twitter users whose previous accounts had been suspended for extremist activity, quantifying the performance of our optimal search policy in this application against other policies. In this application we use thousands of Twitter accounts related to the Islamic State in Iraq and Syria (ISIS) to develop a behavioral models for these extremist users. These models are used to identify new extremist accounts, identify pairs of accounts belonging to the same user, and predict to whom a user will connect when opening an account. We use this final model to inform our network search application. Finally, we develop a more general application of network search and classification that obtains a set of social media users from a specified location or group. We propose an expand -- classify methodology which recursively collects users that have social network connections to users inside the target location, and then classifies all of the users by maximizing the probability over a factor graph model. This factor graph model accounts for the implications of both observed user profile features and social network connections in inferring location. Using geo-located data to evaluate our method, we find that our classification method typically outperforms Twitter's native search methods in building a dataset of Twitter users in a specific location.
by Christopher E. Marks.
Ph. D.
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Grigas, Paul (Paul Edward). "Methods for convex optimization and statistical learning." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106683.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 219-225).
We present several contributions at the interface of first-order methods for convex optimization and problems in statistical machine learning. In the first part of this thesis, we present new results for the Frank-Wolfe method, with a particular focus on: (i) novel computational guarantees that apply for any step-size sequence, (ii) a novel adjustment to the basic algorithm to better account for warm-start information, and (iii) extensions of the computational guarantees that hold in the presence of approximate subproblem and/or gradient computations. In the second part of the thesis, we present a unifying framework for interpreting "greedy" first-order methods -- namely Frank-Wolfe and greedy coordinate descent -- as instantiations of the dual averaging method of Nesterov, and we discuss the implications thereof. In the third part of the thesis, we present an extension of the Frank-Wolfe method that is designed to induce near-optimal low-rank solutions for nuclear norm regularized matrix completion and, for more general problems, induces near-optimal "well-structured" solutions. We establish computational guarantees that trade off efficiency in computing near-optimal solutions with upper bounds on the rank of iterates. We then present extensive computational results that show significant computational advantages over existing related approaches, in terms of delivering low rank and low run-time to compute a target optimality gap. In the fourth part of the thesis, we analyze boosting algorithms in linear regression from the perspective modern first-order methods in convex optimization. We show that classic boosting algorithms in linear regression can be viewed as subgradient descent to minimize the maximum absolute correlation between features and residuals. We also propose a slightly modified boosting algorithm that yields an algorithm for the Lasso, and that computes the Lasso path. Our perspective leads to first-ever comprehensive computational guarantees for all of these boosting algorithms, which provide a precise theoretical description of the amount of data-fidelity and regularization imparted by running a boosting algorithm, for any dataset. In the fifth and final part of the thesis, we present several related results in the contexts of boosting algorithms for logistic regression and the AdaBoost algorithm.
by Paul Grigas.
Ph. D.
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Huang, Dashan. "Studies on quantitative finance via operations research methods." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/135989.
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van, Romondt Vis Pauline. "Changing social scientific research practices : negotiating creative methods." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/22639.
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In recent decades social scientists have started to use qualitative creative methods1 more and more, because of epistemological and methodological developments on the one hand and demands of innovation by governmental funding agencies on the other. In my thesis I look at the research practices of social scientists who use these qualitative creative methods and answer the following main research question: How are practices and approaches from the arts (specifically visual lens-based arts, poetry, performance and narrative) negotiated in social scientific research practice? This question has been divided into the following three sub-questions: 1) How do social scientists negotiate the use of creative methods with other members of their research community? 2) How do social scientists negotiate the use of creative methods into their own research practices? 3) And how do creative methods emerge in the process? Using Lave and Wenger's approach to communities of practice (1991; Wenger, 1998) and Ingold and Hallam's (2007) conceptualisation of improvisation for my theoretical framework, I look at these practices as constantly emerging and changing, but at the same time determined by those same practices. Based on ongoing conversations with postgraduate research students, interviews with experienced researchers, participant observation at conferences and videos of my participants' presentations, I conclude that the use of creative methods is always embedded within existing research practices. When this is not the case, either participants themselves or other academics experience the creative methods as problematic or even as non-academic. In those cases boundarywork (the in- and exclusion of what is deemed academic) is performed more fiercely, making it difficult, if not impossible for creative methods to be truly innovative in the sense that it means a break with previous practices. Instead, we see small shifts in participants' academic practices and how creative methods are taken up in these practices. This means improvisation is a more apt term to describe how creative methods are making their way into social scientific research practices/into the social sciences. As such this conclusion has consequences for the way we think about learning methods, the production of knowledge, innovative methods and (inter)disciplinarity.
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Barapatre, Nirav. "Application of Ion Beam Methods in Biomedical Research." Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-126262.
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The methods of analysis with a focused ion beam, commonly termed as nuclear microscopy, include quantitative physical processes like PIXE and RBS. The element concentrations in a sample can be quantitatively mapped with a sub-micron spatial resolution and a sub-ppm sensitivity. Its fully quantitative and non-destructive nature makes it particularly suitable for analysing biological samples. The applications in biomedical research are manifold.
The iron overload hypothesis in Parkinson\\\'s disease is investigated by a differential analysis of human substantia nigra. The trace element content is quantified in neuromelanin, in microglia cells, and in extraneuronal environment. A comparison of six Parkinsonian cases with six control cases revealed no significant elevation in iron level bound to neuromelanin. In fact, a decrease in the Fe/S ratio of Parkinsonian neuromelanin was measured, suggesting a modification in its iron binding properties.
Drosophila melanogaster, or the fruit fly, is a widely used model organism in neurobiological experiments. The electrolyte elements are quantified in various organs associated with the olfactory signalling, namely the brain, the antenna and its sensilla hairs, the mouth parts, and the compound eye. The determination of spatially resolved element concentrations is useful in preparing the organ specific Ringer\\\'s solution, an artificial lymph that is used in disruptive neurobiological experiments.
The role of trace elements in the progression of atherosclerosis is examined in a pilot study. A differential quantification of the element content in an induced murine atherosclerotic lesion reveals elevated S and Ca levels in the artery wall adjacent to the lesion and an increase in iron in the lesion. The 3D quantitative distribution of elements is reconstructed by means of stacking the 2D quantitative maps of consecutive sections of an artery.
The feasibility of generating a quantitative elemental rodent brain atlas by Large Area Mapping is investigated by measuring at high beam currents. A whole coronal section of the rat brain was measured in segments in 14 h. Individual quantitative maps of the segments are pieced together to reconstruct a high-definition element distribution map of the whole section with a subcellular spatial resolution. The use of immunohistochemical staining enhanced with single elements helps in determining the cell specific element content. Its concurrent use with Large Area Mapping can give cellular element distribution maps.
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Garrett, Peter. "Language attitudes : methods and interpretation in sociolinguistic research." Thesis, Cardiff University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420328.
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Gerstner, Christian. "Online sociological research : methods, ethics and the law." Thesis, Keele University, 2013. http://eprints.keele.ac.uk/3823/.
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This thesis offers a comprehensive examination of the dilemmas posed by cyberspace for contemporary social research and in how far current ethical frameworks can manage the risks that may emerge in this new research environment. The study is situated in the period of 1998 to 2010, during which the social uses of rapidly converging technological tools led to the extension of the social world into a new social sphere of social interaction called cyberspace. Social scientists have been quick to explore this sphere; however, as the dominant discourses are based on ideas of newness and difference there is uncertainty over what kind of space it is, whether we can transfer existing methods and ethics and what rules apply in the conduct of research. The thesis first investigates the extent to which the technological tools and ethical dilemmas encountered in cyberspace are in fact new or different. This then necessitates a detailed engagement with the conceptualisation of cyberspace. Thereafter it closes a gap in dominant conceptualisations of cyberspace by offering insights into its legal and regulatory foundations. Next, the thesis reflects on legislation and regulations to identify emerging risks that emerge in everyday social research practice in the online environment. These risks are then used as vignettes to test current ethical guidance’s ability to manage them. The thesis argues that disciplines within the social sciences need to be continually reflexive about their encounters with new spaces, and concludes that cyberspace demands significant engagement with the difficulties posed by the rapid pace of change of technological development and regulatory and legislator foundations in order to manage risk in online social research. Thus while online research is the focus, the potential of this thesis is to offer a historical insight into the reflexivity of the discipline in particular in how successfully it encounters new spaces of/for research.
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Richaud, de Minzi María Cristina. "New statistical methods for research in personality assessment." Pontificia Universidad Católica del Perú, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/99784.
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In the present work a review of the new multivariate techniques and why they appear especiallysuited to the personality research is presented. Emerging models of personality and advances in the measurement of personality and psychopathology suggest that research in this field has ente red a stage of advanced development. The past two decades have shown importan! developments in statistics and measurement. Refinement of multivariate statistics has been especially importan! in personality assessment because of the complexity of relations among personality variables. Multivariate procedures provide the opportunity to examine the complexity of these interactions by providing methods of analysis for multiple variables. On the other hand, structural equation modeling and multivariate techniques for analyzing categorical variables have been developed. Multidimensional scaling and item response theory are the last developments.En este trabajo se realiza una revisión de las nuevas técnicas estadísticas y de su utilidad para la investigación en personalidad. Los nuevos modelos y los avances en la medición de la personalidad y la psicopatología sugieren que la investigación en este campo y en su evaluación han entrado en un estadio avanzado de desarrollo. En las dos últimas décadas se han producido importantes desarrollos en estadística y medición. El refinamiento de las técnicas de análisis multivariado ha sido fundamental en la evaluación de la personalidad debido a la complejidad de las relaciones entre sus variables. Los procedimientos de análisis multivariado proveen la oportunidad de examinar la complejidad de esas interacciones a través de métodos de análisis para variables múltiples. Por otra parte, se han desarrollado los modelos de ecuaciones estructurales y técnicas multivariadas para analizar variables categóricas. Los últimos desarrollos corresponden al escalamiento multidimensional y a la teoría de la respuesta al ítem.
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Davis, Mary, Alexis Gonzales, Kyle Wolske, and Brenda Louw. "Imagine More Diversity in CSD Research Methods Coursework." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/7754.
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Insufficient research training contributes to the current shortage of researchers in the field of speech-language pathology and contributes to the dearth of multicultural and multilingual (MCML) research. There is limited information regarding how MCML issues are addressed in Research Methods courses in CSD. This research explores the extent to which MCML issues are included in CSD Research courses.Learner Outcome(s): Identify the importance of MCML in research method courses Describe ASHA MCML resources Describe strategizes to integrate MCML issues into coursework
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Le, Phuoc Hoang. "Payoff allocation methods for several operational research games." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412546/.
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From the start of this century, enforcing and maintaining collaborations became one of the trends in business and management, ranging from production and inventory to transportation and network communication. Because of the economies of scale, many enterprises might collaborate to generate more value and save costs instead of working on their own. The rapid change in science and information technologies enables users to communicate and share data more efficiently through different digital platforms. These emerging technologies open several opportunities for companies and institutions to allow potential coordination and collaboration. This development has created the sharing economy which enables individuals, households, businesses, and organisations to engage in collaborative production, distribution, and consumption of goods and services. The interactions among players willing to cooperate are the underlying theme of Cooperative Game Theory. In this field, payoff (yield/cost) sharing problems aim at producing solutions with two main criteria: fairness and stability. These principles lead to some popular solution concepts such as the Shapley value and the core, which concern distributing the payoff to members of a coalition. The main contributions of this thesis are the developments of some computationally efficient methods to calculate these solution concepts in the generalised minimum spanning tree, linear production, and multidimensional integer knapsack games. These are the subclasses of operational research games where the characteristic functions of these cooperative games are described by linear or integer linear programming formulations. The minimum-cost spanning tree game is a particular class of cooperative games defined on a graph, where each player owns a vertex. Solutions of the game represent ways to distribute the total cost of a minimum-cost spanning tree among all the players. When we partition the graph into clusters, the generalised minimum spanning tree problem is to determine a minimum-cost tree including exactly one vertex from each cluster. The first chapter introduces and studies the generalised minimum spanning tree game and some of its properties. We propose a constraint generation algorithm to calculate a stable payoff distribution and present some computational results obtained using the proposed algorithm. Another class of operational research games, called linear production game, is concerned with allocating the total payoff of an enterprise among the owners of the resources in a fair way. With cooperative game theory provides a mathematical framework for sharing the benefit of the cooperation, the Shapley value is one of the widely used solution concepts as a fair measurement in this area. Finding the exact Shapley values for linear production games is, however, challenging when the number of players exceeds 30. This chapter describes the deploy of linear programming sensitivity analysis for more efficient computation. We also propose the stratified sampling technique to estimate the Shapley value for large-scale linear production games. Computational results show the effectiveness of these compared to other existing methods. The integer optimisation game, where the characteristic function is generated by solving an integer optimisation problem, forms an important class in cooperative game theory. In this chapter, we introduce a new subclass of integer optimisation games namely the multidimensional integer knapsack game. Finding the Shapley value is challenging for most integer optimisation games with a large number of players, particularly for the multidimensional integer knapsack game due to the structure of its characteristic function. We describe an algebraic approach using Grobner bases to be able to compute the Shapley value efficiently. Some computational experiments are presented to show the potential of the proposed method compared to CPLEX, the state-of-the-art commercial solver on some randomly generated instances.
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Ooi, Phillip S. K. "Design methods for deep foundations." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/28503.
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Groschel, Uwe. "Audiences and participants : researching theatre users at Contact, Manchester." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/audiences-and-participants-researching-theatre-users-at-contact-manchester(ed0dbc91-5fc5-44ea-a7c8-627691ab8e1e).html.
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When people 'go to the theatre' we know that they are audiences. When young people go to Contact, however, they might be audiences, performers and/or theatre makers - they might play all three or more roles. Contact's users blur existing concepts and terminology. When we want to know more about theatre audiences, audience research offers models based on the distinction between audiences and theatre makers. If we want to know more about Contact's users, however, a model reflecting the blending of audiences and theatre makers' roles has yet to be developed. This thesis engages with Contact's users. It maps some of their multiple roles and experiences by asking two main questions: What are the practices of the people attending Contact and how can these practices be researched? A range of qualitative methods is necessary in order to investigate the wide variety of Contact's users' roles and experiences. Individual and group interviews are drawn from audience research, creative workshops are drawn from communication studies, and participant observation and visual research from the social sciences. Finally, a new method, Walking Fieldwork, is adapted for the use in theatre. A number of case studies are employed to investigate Contact's users. These case studies involve the observation of young actors during rehearsals and performances, the observation of participants in an outreach project, the investigation of audiences' experiences of two productions, and several short post-show interviews with general Contact audiences. This study found evidence that the relationship between theatre makers and audiences is changing. The term 'theatre user' is introduced as it opens up an area of overlap between the two and fits contemporary practices at Contact more closely. Contact's users function as communities, participants and co-creators. The descriptions of these roles and experiences contained in this thesis are understood as an initial exploration into practices of contemporary theatre users. However, further research is needed to build a more detailed understanding of these practices. In terms of research methods, this study found that the academic field of audience research needs to develop methods which are sensitive to both the backgrounds of theatre users and the theatrical context. The argument is put forward that audience research should become more aware of methods for the investigation of human experience and should enter into a 'methods-dialogue' with other academic fields of study.
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Hardcastle, J. L. "Novel voltammetric methods in heavily passivating media." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:7ef17e49-dd12-4c3b-b2a0-b94605ccb1fa.
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The work contained in this thesis demonstrates that the introduction of power ultrasound into electrochemical systems can broaden the scope of techniques such as anodic stripping voltammetry. Analysis is facilitated by the well-documented phenomena associated with ultrasound, cavitation and acoustic streaming. Cavitation is caused by the collapse of voids created by ultrasonic compression and rarefaction of the solution and results in both localised high temperatures and pressures in the bulk solution and microjetting on the surface. Precise mechanistic details are still open to debate but there is evidence to suggest that shear forces at the interface when the electrode is flushed are responsible for removing organic material (particularly large species such as proteins) facilitating continuous cleaning and activation of the surface. Acoustic streaming has been shown to give diffusion layer thicknesses of the order of 1-10 μm depending on solvent and ultrasound power. The increased mass transport at such low diffusion layer thicknesses results in shorter preconcentration periods in electrochemical stripping voltammetry, greater sensitivity and a correspondingly lowered detection limit. Often ultrasound has been applied to highly passivating systems where conventional silent electroanalysis fails with the effect of transforming invisible or tiny voltammetric signals into large and quantitative responses suitable for sensitive and accurate analytical purposes. In Section IIthe relative contributions of acoustic streaming and cavitationally induced microjetting to the sonovoltammetric response is assessed. Chronoamperometry at insonated electrodes of both micro and macro dimensions, and differential pulse voltammetry (DPV) were used to explore the frequency and violence of cavitational events and the nature of the diffusion layer prevailing under steady-state electrolysis. The results lead to a physical model of an insonated electrode which may be described as a steady diffusion layer a few microns thick brought about by acoustic streaming which is occasionally and randomly punctuated by a cavitational event. The frequency and violence of the event is dependent on the solvent and ultrasound power, except at very short electrode-to-horn separation where the cavitational contribution becomes substantial. Section II concentrates on the implementation of the technique with applications to the detection of heavy metals in biofluids. In Chapter 4 sonoelectroanalysis is applied to the detection of copper bound within human blood protein and whole blood. It is shown that the enhancement of square wave anodic stripping peaks observed in ceruloplasmin and whole blood is not simply due to mass transport enhancement and cavitational cleaning effects alone but also the liberation of copper from the active sites in which it is bound prior to preconcentration. The results of a quantitative determination of total copper in two samples of whole blood were 1300 μg L-1 and 620 μg L-1, verified by independent blind analysis using atomic absorption spectroscopy (AAS). The need for rapid analysis of environmental samples can also be fulfilled using sonoelectroanalysis. In Chapter 5 fish gill mucus is used as a non-destructive biomarker for the detection of heavy metals by sono-square wave anodic stripping voltammetry (sono-SWASV). A quantitative assessment of copper content yielded values of 16 μgL-1 and 21 μgL-1 which compared favourably with independent blind analysis by AAS. The potential of the technique for detection of other heavy metals for example lead, was also demonstrated. Lead poisoning is recognized as a major environmental health risk and in Chapter 6 quantitative analysis of lead in artificial saliva from a realistic sputum volume, 220 μL, introduced to acetate buffer is investigated. An insonated preconcentration obviates the need for lengthy or degradative sample pretreatment by liberating the lead from the glycoproteins and other materials to which it binds in solution. Quantitative depassivation of the electrode surface by cavitational shearing maintained the analytical signal throughout the experiment where under silent conditions the signal diminished to zero with time. The detection limit in the analyte is 0.25 μg L-1. Following this proof of concept, Chapter 7 goes on to apply the technique to the quantitative determination of lead and cadmium in real human saliva. Close agreement between lead concentration determined by sono-SWASV and independent and blind ICP-MS is reported for human saliva samples with detection limits of 0.5 μg L-1 lead and 1 μg L-1 cadmium in saliva. Section IV harnesses the benefits of acoustic emulsification. Power ultrasound is capable of forming droplets of micron dimensions with lower energy consumption than conventional emulsifiers. Chapter 8 acoustic emulsification is employed in the detection of vanillin (4-hydroxy-3-methoxybenzaldehyde) in vanilla essence using ethyl acetoacetate as a novel electrochemical and sonoelectrochemical solvent. Contrasting with silent voltammetry, ultrasound facilitates emulsification and extraction of vanillin in the extract permitting an analytical square wave voltammetric signal to be obtained. Close agreement with a blind analysis of the samples using HPLC-UV is observed with a limit of detection in the biphasic medium of 0.020 mM. In Chapter 9 acoustic emulsification is utilized in the solvent extraction of copper. Ultrasonic emulsification of an aqueous phase containing copper ions with the N-benzoyl-N-phenyl-hydroxylamine ligand in an organic ethyl acetate phase was shown to facilitate the extraction of copper into the organic phase at 25°C. Subsequent emulsification with 1 M acid "back-extracts" or "re-strips" the copper into the aqueous phase prior to analysis via sono-SWASV. The technique necessarily removes contaminants present in the test solution since these will prefer to remain in the initial aqueous phase, or will transfer to the organic phase but are unlikely to be doubly transferred into the "clean" final aqueous phase. In Chapter 10 the technique is applied to the analysis of copper in the soft drink "Ribena® Light" with a detection limit of 2 μg L-1 and copper in blood with a detection limit of 0.16 μg L-1. In the latter case the analysis required a sample volume of 100 μL suggesting that a pinprick test may be feasible. Finally in Section V, the analysis of copper in the presence of surfactants is investigated. Surfactant adsorption has been shown to have a passivating effect on the electrode surface during anodic stripping voltammetric measurements. Effluent, both industrial and domestic, is commonly contaminated with surfactant and electroanalysis of heavy metals is frequently precluded. It is therefore desirable to formulate a new analytical strategy in waste water. This is facilitated by controlled experiments with known amounts of anionic, cationic or neutral surfactant which also provides an ideal model system for comparing the techniques introduced in earlier Chapters. "Direct" sonoelectroanalysis in the medium of interest is compared with biphasic sono-solvent double extraction and both are appraised in the light of novel sonotrode technology. This thesis concludes that sonoelectroanalysis is a powerful and versatile analytical tool that can be employed in an expanding range of applications. The examples given herein are pertinent to the major fields of medical diagnosis and the assessment of environmental pollution. They demonstrate that sonoelectroanalysis is a viable alternative to conventional analytical techniques which have the disadvantages of more lengthy sample pretreatment and cost.
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Eglington, T. I. "An investigation of kerogens using pyrolysis methods." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380730.
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Papush, Anna. "Data-driven methods for personalized product recommendation systems." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115655.
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Thesis: Ph. D., Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
The online market has expanded tremendously over the past two decades across all industries ranging from retail to travel. This trend has resulted in the growing availability of information regarding consumer preferences and purchase behavior, sparking the development of increasingly more sophisticated product recommendation systems. Thus, a competitive edge in this rapidly growing sector could be worth up to millions of dollars in revenue for an online seller. Motivated by this increasingly prevalent problem, we propose an innovative model that selects, prices and recommends a personalized bundle of products to an online consumer. This model captures the trade-off between myopic profit maximization and inventory management, while selecting relevant products from consumer preferences. We develop two classes of approximation algorithms that run efficiently in real-time and provide analytical guarantees on their performance. We present practical applications through two case studies using: (i) point-of-sale transaction data from a large U.S. e-tailer, and, (ii) ticket transaction data from a premier global airline. The results demonstrate that our approaches result in significant improvements on the order of 3-7% lifts in expected revenue over current industry practices. We then extend this model to the setting in which consumer demand is subject to uncertainty. We address this challenge using dynamic learning and then improve upon it with robust optimization. We first frame our learning model as a contextual nonlinear multi-armed bandit problem and develop an approximation algorithm to solve it in real-time. We provide analytical guarantees on the asymptotic behavior of this algorithm's regret, showing that with high probability it is on the order of O([square root of] T). Our computational studies demonstrate this algorithm's tractability across various numbers of products, consumer features, and demand functions, and illustrate how it significantly out performs benchmark strategies. Given that demand estimates inherently contain error, we next consider a robust optimization approach under row-wise demand uncertainty. We define the robust counterparts under both polynomial and ellipsoidal uncertainty sets. Computational analysis shows that robust optimization is critical in highly constrained inventory settings, however the price of robustness drastically grows as a result of pricing strategies if the level of conservatism is too high.
by Anna Papush.
Ph. D.
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Schier, Christa Marianne. "Qualitative Internet research : its objects, methods and ethical challenges." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4356.
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Bivalkevich, Elizaveta. "The value of scientific research in accounting." Thesis, ГО "Європейська наукова платформа", 2021. https://er.knutd.edu.ua/handle/123456789/18955.
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The main task of research in the field of accounting is primarily to identify and address the problems of theory, methodology, and organization of accounting, economic analysis, and control, in order to ensure the achievement of society's goals taking into account the interests of business entities and patterns of the historical development of the accounting profession.
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Allen, Peter James. "Engaging Undergraduate Psychology Students with Research Methods and with the Process of Conducting Research." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/54162.
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A strong understanding of quantitative research methods is a pre-requisite to psychological literacy and evidence-based practice in psychology. Quantitative research methods are also an area of weakness for many psychology students. Furthermore, many students have relatively little interest in reading and conducting research, hold negative attitudes toward research methods, struggle to see the relevance or utility of methods and statistics courses, and experience high levels of statistics anxiety. Consequently, efforts have been undertaken to reform traditional research methods and statistics pedagogy, with the objective of making these subjects more applied, relevant and engaging for students. Many of these reforms are based on active learning principles, and the idea that, as much as is practicable, students should be ‘doing’ research, rather than merely reading about it, or listening to instructors talking about it. In an undergraduate psychology degree, ‘doing research’ can manifest in multiple activities, of which the current thesis focuses on three: (1) participating in authentic research; (2) working with authentic data; and (3) conducing an original research project.
The first two papers herein focus on understanding and quantifying undergraduate psychology students’ perspectives on the educational value of participating in authentic research, which is a ‘rite of passage’ in most research active schools of psychology. The third describes the development and evaluation of an active learning exercise in which students participated in a class experiment, then analysed the data it generated. Papers 4-7 address issues arising from the supervision of final year dissertations projects, including the quality of student collected data, and the ethics of surveying online. Finally, paper 8 explores the difficulties faced by students (but not ‘experts’) when required to identify statistical tests and procedures appropriate to their research questions and hypotheses, while paper 9 describes the development of a mobile application specifically developed to support this process. Combined with the exegesis that precedes them, the nine papers in this thesis offer a range of insights into, and strategies that promote the engagement of undergraduate psychology students with research methods, and with the process of conducting research.
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AKSAKALLI, VURAL. "Heuristic Methods for Gang-Rip Saw Arbor Design and Scheduling." NCSU, 1999. http://www.lib.ncsu.edu/theses/available/etd-19991102-031914.
Full textAbstract:
AKSAKALLI, VURAL. Heuristic Methods for Gang-Rip Saw Arbor Design and Scheduling. (Under the direction of Dr. Yahya Fathi).This research considers the problem of designing and scheduling arbors for gang-rip saw systems. Such systems are typically used within the furniture manufacturing industry for processing lumber, where lumber boards are first ripped lengthwise into strips of different widths, and then, cut to the required lengths to be used in manufacturing.A saw with multiple cutting channels is used to perform this operation. This saw has fixed blades at specific positions on a rotating shaft which rips incoming lumber boards into required finished widths. The pattern of cutting channels (i.e., the setting of the blades) along the saw shaft is referred to as an ''arbor''.A typical instance of the problem consists of (1) a set of required finished widths and their corresponding demands, (2) a frequency distribution of lumber boards in the uncut stock, (3) a shaft length, and (4) a blade width. The objective is to design a set of (one or more) arbors and the corresponding quantity of lumber to run through each arbor, such that the total amount of waste generated is minimized while the demand is satisfied.In the research, we focus on solving the problem using only one arbor. First, we discuss the computational complexity of the problem and propose a total enumeration procedure which can be used to solve relatively small instances. Then, we develop algorithms based on heuristic approaches such as local improvement procedures, simulated annealing, and genetic algorithms. Our computational experiments indicate that a local improvement procedure with two nested loops, performing local search with a different neighborhood structure within each loop, gives very high quality solutions to the problem within very short execution times.
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Makaya, Makaya L. "Interactive methods for multiple objective linear programming in decision support." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/4385.
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Bishop, Joanna Kelly. "Predictable feeding in zoos : research methods and behavioural effects." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1580.
Full textAbstract:
The behaviour of zoo animals can come to anticipate temporally predictable feeding times. However, there is a lack of consensus over the effects of such routines on behaviour and welfare. Few studies have been published in this area, perhaps in part due to methodological challenges. The current programme of work therefore aimed to extend knowledge on the effect of predictable feeding routines, and to develop a suitable methodology to overcome challenges. Prior to predictable feeding, tigers showed patterns of increased ‘active’ behaviours such as locomotion and pacing, and decreased inactivity. Geckos also showed increased ‘active’ behaviours such as locomotion and ‘stationary but moving head’ prior to predictable, compared to unpredictable feeding times, with significant differences between conditions (RSS = 0.059 and 0.047, p < .05). However, anticipatory patterns were not demonstrated for meerkats, which highlighted that other environmental factors may affect an animal’s response to temporal predictability (such as obtaining other food during the day, or signalled predictability). Studying patterns of behavioural change over time requires long periods of observation which is often not possible for researchers. The current programme of work argues that a measure which can be reliably used by many, relatively untrained observers is necessary to study predictability. The measure of ‘busyness’, a subjective rating of animal behaviour, was tested for reliability and validity. Busyness ratings showed good inter-observer reliability (ICC > .72) and correlated with traditional measures of behaviour. Busyness ratings demonstrated clear patterns related to feeding time and gave a useful compound measure of behavioural change. The use of multiple observers was extended to a citizen science approach, where useful data on anticipation in fish were obtained from aquarium visitors using a touch screen. The current programme of work successfully investigated the effects of predictable feeding routines on patterns of animal behaviour, alongside the development of suitable methods. The qualitative techniques developed here offer potential to increase the data obtained in future research into predictability and many other topics.