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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.
21

Knowledge Provenance: An Approach to Modeling and Maintaining The Evolution and Validity of Knowledge

Huang, Jingwei 28 July 2008 (has links)
The Web has become an open decentralized global information / knowledge repository, a platform for distributed computing and global electronic markets, where people are confronted with information of unknown sources, and need to interact with “strangers”. This makes trust and the validity of information in cyberspace arise as crucial issues. This thesis proposes knowledge provenance (KP) as a formal approach to determining the origin and validity of information / knowledge on the Web, by means of modeling and maintaining the information sources, information dependencies, and trust structures. We conceptualize and axiomatize KP ontology including static KP and dynamic KP. The proposed KP ontology, provides a formal representation of linking trust in information creators and belief in the information created; lays a foundation for further study of knowledge provenance; provides logical systems for provenance reasoning by machines. The web ontology of KP can be used to annotate web information; and KP reasoner can be used as a tool to trace the origin and to determine the validity of Web information. Since knowledge provenance is based on trust in information sources, this thesis also proposes a logical theory of trust in epistemic logic and situation calculus. In particular, we formally define the semantics of trust; from it, we identify two types of trust: trust in belief and trust in performance; reveal and prove that trust in belief is transitive; trust in performance is not, but by trust in belief, trust in performance can propagate in social networks; by using situation calculus in trust formalization, the context of trust is formally represented by reified fluents; we also propose a distributed logical model for trust reasoning using social networks, by which each agent’s private data about trust relationships can be protected. This study provides a formal theoretical analysis on the transitivity of trust, which supports trust propagation in social networks. This study of trust supports not only knowledge provenance but also the general trust modeling in cyberspace.
22

Adding gender to the archival contextual turn: the Rocky Mountain photographic records of Mary Schäffer Warren

Rutkair, Jennifer 21 December 2011 (has links)
This thesis explores the significance of gender as an overlooked element of context in understanding the provenance of archival records. The relevance of gender to archival provenance is demonstrated through a case study analysis of the gendered contexts of record creation, use, and meaning. The analysis is grounded in an examination of the archival photographic and textual records of Mary Schäffer Warren, an amateur photographer, traveller, and explorer of the Canadian Rocky Mountains during the years 1888 and 1939. This thesis argues that gender is an important context in a record’s provenance providing nuanced understandings of socio-cultural relations and processes of record creation, use, and meaning. Gender as context further empowers the principle of provenance by more fully reflecting how and why records are created which accordingly allows archivists to appraise, acquire, and describe records in ways more sensitive to gender as a socio-cultural reality.
23

The effects of ceramic manufacturing behaviour on identifying clay sources: petrographic and chemical analyses of the modern Zulu ceramic production process in the Thukela River Basin, South Africa

Middleton, Emma C. 16 August 2012 (has links)
This thesis aims to evaluate the compositional changes that occur when raw clays are transformed into finished vessels, and how these compositional changes impact provenance research. Petrographic and chemical techniques are used to analyse clays at each stage in the production sequence used by Zulu potters in KwaZulu-Natal, South Africa. The results of this research demonstrate that tempering behaviour, particularly the mixing of clays, can significantly alter the composition of ceramic vessels, depending on the ratio of clay types. The provenance of mixed clays and vessels can be determined when the range of variation between clay sources is known. Different ratios of constituent clays significantly affect the composition of finished vessels.
24

Knowledge Provenance: An Approach to Modeling and Maintaining The Evolution and Validity of Knowledge

Huang, Jingwei 28 July 2008 (has links)
The Web has become an open decentralized global information / knowledge repository, a platform for distributed computing and global electronic markets, where people are confronted with information of unknown sources, and need to interact with “strangers”. This makes trust and the validity of information in cyberspace arise as crucial issues. This thesis proposes knowledge provenance (KP) as a formal approach to determining the origin and validity of information / knowledge on the Web, by means of modeling and maintaining the information sources, information dependencies, and trust structures. We conceptualize and axiomatize KP ontology including static KP and dynamic KP. The proposed KP ontology, provides a formal representation of linking trust in information creators and belief in the information created; lays a foundation for further study of knowledge provenance; provides logical systems for provenance reasoning by machines. The web ontology of KP can be used to annotate web information; and KP reasoner can be used as a tool to trace the origin and to determine the validity of Web information. Since knowledge provenance is based on trust in information sources, this thesis also proposes a logical theory of trust in epistemic logic and situation calculus. In particular, we formally define the semantics of trust; from it, we identify two types of trust: trust in belief and trust in performance; reveal and prove that trust in belief is transitive; trust in performance is not, but by trust in belief, trust in performance can propagate in social networks; by using situation calculus in trust formalization, the context of trust is formally represented by reified fluents; we also propose a distributed logical model for trust reasoning using social networks, by which each agent’s private data about trust relationships can be protected. This study provides a formal theoretical analysis on the transitivity of trust, which supports trust propagation in social networks. This study of trust supports not only knowledge provenance but also the general trust modeling in cyberspace.
25

Adding gender to the archival contextual turn: the Rocky Mountain photographic records of Mary Schäffer Warren

Rutkair, Jennifer 21 December 2011 (has links)
This thesis explores the significance of gender as an overlooked element of context in understanding the provenance of archival records. The relevance of gender to archival provenance is demonstrated through a case study analysis of the gendered contexts of record creation, use, and meaning. The analysis is grounded in an examination of the archival photographic and textual records of Mary Schäffer Warren, an amateur photographer, traveller, and explorer of the Canadian Rocky Mountains during the years 1888 and 1939. This thesis argues that gender is an important context in a record’s provenance providing nuanced understandings of socio-cultural relations and processes of record creation, use, and meaning. Gender as context further empowers the principle of provenance by more fully reflecting how and why records are created which accordingly allows archivists to appraise, acquire, and describe records in ways more sensitive to gender as a socio-cultural reality.
26

The effects of ceramic manufacturing behaviour on identifying clay sources: petrographic and chemical analyses of the modern Zulu ceramic production process in the Thukela River Basin, South Africa

Middleton, Emma C. 16 August 2012 (has links)
This thesis aims to evaluate the compositional changes that occur when raw clays are transformed into finished vessels, and how these compositional changes impact provenance research. Petrographic and chemical techniques are used to analyse clays at each stage in the production sequence used by Zulu potters in KwaZulu-Natal, South Africa. The results of this research demonstrate that tempering behaviour, particularly the mixing of clays, can significantly alter the composition of ceramic vessels, depending on the ratio of clay types. The provenance of mixed clays and vessels can be determined when the range of variation between clay sources is known. Different ratios of constituent clays significantly affect the composition of finished vessels.
27

Axe-Heads and Mississippian Political Economy: A St. Francois Provenance Study

Crow, Rosanna Yvonne 01 August 2014 (has links)
Axe-heads made of a distinctive raw material are found at Mississippian sites across southern Illinois and the Ohio-Mississippi confluence region, yet little research has been done to determine their geological provenance. In this thesis, I use geochemical methods to analyze ground stone tools and debitage from across the Confluence Region in order to prove their origins in the St. Francois Mountains of Missouri. I also compare patterns of axe-head production, consumption, and deposition to Charles Cobb's (2000) model of Mill Creek chert hoes, so as to gain a greater understanding of the political economy of these objects.
28

Geoquímica e proveniência do Grupo Bauru no Oeste de Minas Gerais / Geochemistry and provenance of Bauru Group on West Minas Gerais State

Mattos, Nathália Helena Secol, 1988- 08 August 2014 (has links)
Orientador: Alessandro Batezelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-25T21:40:30Z (GMT). No. of bitstreams: 1 Mattos_NathaliaHelenaSecol_M.pdf: 5195246 bytes, checksum: 2551186b0e4a53abcac203b4227922a3 (MD5) Previous issue date: 2014 / Resumo: Estudos geoquímicos e mineralógicos de arenitos e argilitos da Bacia Bauru (Cretáceo Superior), localizada na região do Triângulo Mineiro (Minas Gerais) foram realizados visando à determinação da proveniência, tectônica da rocha fonte, o papel de processos como intemperismo e reciclagem sedimentar na assinatura geoquímica da rocha fonte e à proposição de um modelo de evolução paleoambiental para a área de estudo. As amostras tem sua mineralogia principal composta por quartzo, microclínio, calcita, albita, dolomita e hematita. Illita, montmorillonita e paligorsquita são os argilominerais identificados. Elementos maiores, traços e terras raras e as razões elementares entre eles foram utilizadas para determinar a composição da rocha fonte. Valores do Índice Químico de Alteração e do Índice de Intemperismo Químico variando de 64 a 92 e de 84 a 98, respectivamente, e a ocorrência de feldspatos nas rochas sedimentares indicam intemperismo químico moderado na área fonte. Gráficos de elementos maiores e traços e valores para razões como La/Sc (1,47-4,86), (La/Yb)c (3,86-20,44) e a anomalia de Eu (Eu/Eu* = 0,62-0,92) comparados com dados da literatura sugerem que os sedimentos da Bacia Bauru na área de estudo tenham sido originados de rochas de composição quartzítica a granítico-gnáissica, derivadas de áreas continentais estáveis e depositados em ambientes de bacias intracratônica. A possível área-fonte para as rochas estudadas localiza-se a NE da Bacia Bauru, consistindo em rochas graníticas e metassedimentares do embasamento pré-cambriano. A deposição sedimentar na Bacia Bauru reflete a interação de processos aluviais e lacustres / Abstract: Geochemical and mineralogical studies of sandstones and mudstones from the Late Cretaceous Bauru Basin of Triângulo Mineiro region (Minas Gerais State) were undertaken to determine the provenance, tectonic setting, the role of weathering, sorting and recycling on the source rock geochemical signature and to propose a palaeoenvironmental evolution model to the study area. The analysed samples are mainly composed by quartz, microcline, calcite, albite, dolomite and hematite. Illite, montmorillonite and palygorskite are the identified clay minerals. Major elements were used to determine the source rock composition, as well as trace and rare earth elements and the ratios among them. Chemical Index of Alteration and Chemical Index of Weathering ranging from 64.83 to 92.3 and from 84 to 98.2, respectively, along with the feldspar occurrence on sedimentary rocks indicate a moderate weathering in the source area. Plots of major and trace elements and values for the ratios such as La/Sc (1.47-4.86), (La/Yb)c (3.86-20.44) and the Eu anomaly (Eu/Eu*= 0.62-0.92), compared to data from the literature indicate source rock was located into a continental passive margin tectonic setting and sediments were derived from quartzitic to granitic-gneissic rocks of stable continental areas and deposited in an intracratonic basin. Probable source area to the studied rocks is located at NE of Bauru Basin and consists in granitic and metassedimentary rocks from the Precambrian basement. Sedimentary deposition in Bauru Basin reflects an interaction of alluvial and processes / Mestrado / Geologia e Recursos Naturais / Mestra em Geociências
29

Provenance analyses of neoproterozoic/early palaeozoic glacial (?) deposits from southwestern Gondwana

Van Staden, Anelda 07 June 2012 (has links)
Ph.D. / Louis Agassiz first raised the concept of a global ice age followed by an intriguing history of both proponents and opponents of the idea simultaneously contributing towards the evolution of geological notions up to the present-day ‘Snowball Earth’ model. The causes of glaciation and the sedimentary, geochemical and stratigraphic feedbacks subsequently received renewed interest. Different deposits of possible Neoproterozoic glacial successions were thus selected for detailed provenance analyses in this study. The successions selected are the Puncoviscana Formation on the Pampia Terrane (Northwestern Argentina), the Sierra del Volcán diamictite of the Tandilia System on the Río de la Plata craton (Eastern Argentina), the Kaigas and Numees Formations of the Richtersveld and Gariep areas on the Kalahari craton (Northwest South Africa and Southern Namibia) and the Karoetjes Kop Formation and Swartleikrans Bed of the Bloupoort Formation of the Vanrhynsdorp region on the Kalahari craton (Western South Africa). Diagnostic physicochemical aspects are utilized to ascertain whether the deposits studied are firstly of glacial derivation and, secondly, to constrain the provenance of every deposit. The latter culminate with identification of a regionally or globally significant event. The Sierra del Volcán diamictite is a glacial diamictite with a depositional age younger than 485±2 Ma and is correlatable with the Upper Ordovician Pakhuis Formation (Table Mountain Group) in South Africa. The recognition of a glacial deposit of Upper Ordovician age in eastern Argentina suggests that the Hirnantian ice sheet cover extended from southwest South Africa to eastern Argentina, stretching from the central Paraná basin across into central and northwest Argentina and southern Bolivia. A proximal glacial marine depositional environment is inferred within a subaqueous outwash fan deposited by sediment gravity flow. Periglacial deposits occur in the Pakhuis Formation, suggesting that the ice sheet had retreated with deposition in glacial outwash plains by braided river systems and windblown loess.
30

Hominin survival and lithic procurement strategies at a Pleistocene desert refugium during periods of environmental stress: a case study from Shishan Marsh 1 in the Azraq Basin, Jordan

Beller, Jeremy A. 11 January 2021 (has links)
A century of intermittent archaeological research in the Azraq Basin of the eastern desert of Jordan has demonstrated that a long period of hominin occupation exists in this environmentally inhospitable region during the Pleistocene. Recent excavations at the site of Shishan Marsh 1 in the Azraq Basin have uncovered several artifact-bearing layers that correspond to the Middle (266 ± 40 kya) and Upper (125 ± 12 kya) Pleistocene. An examination of paleoclimatic data from this period indicates predominantly warm and dry conditions in the region and a gradual reduction of water availability. These factors forced hominins to modify their resource acquisition strategies and exploit the receding spring- and wadi-fed Azraq wetlands. This dissertation investigates the nature of lithic procurement strategies practiced by hominins at Shishan Marsh 1, a Middle-Upper Pleistocene site in the former wetlands, during periods of environmental stress. It involves a provenance analysis of sources within the region and a sample of lithic artifacts from Shishan Marsh 1 through laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results indicate that the artifacts were procured from local and regional sources and likely through embedded procurement in an effort to provision individuals. They further provide insight into the nature of survival within the Azraq Basin, as hominin groups performed tethered mobility whereby they contracted around the Azraq wetlands. In this case, this stable water source operated as a desert refugium for hominins within the Azraq Basin. / Graduate / 2021-11-13

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