• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 876
  • 587
  • 128
  • 109
  • 90
  • 68
  • 62
  • 23
  • 21
  • 15
  • 10
  • 10
  • 9
  • 8
  • 8
  • Tagged with
  • 2375
  • 334
  • 303
  • 284
  • 258
  • 254
  • 238
  • 238
  • 201
  • 196
  • 183
  • 180
  • 179
  • 179
  • 175
  • 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.
81

Telepathy in contemporary, conceptual and performance art

Drinkall, Jacquelene Ashley, School of Art History & Theory, UNSW January 2005 (has links)
This thesis investigates the impact of telepathy and psi on conceptual and performance art from 1968. Emerging from the author???s art practice, the thesis argues telepathy is a key leitmotif and creative concern within much post 60s art, and has become central to the practice of a number of contemporary video, performance and new media artists. This thesis is composed of two interrelated parts: an exhibition of the artwork by the author concerning telepathic processes, and a written project which uses the major themes of the exhibition to frame an historical study of a number of key contemporary artists whom, it is argued, work with telepathy. These artists, Jane and Louise Wilson, Suzanne Treister and Susan Hiller are discussed under the themes of ???twinning and doubling,??? ???technological mediums??? and ???telepathy experiments???. These themes also overlap in the authors artwork, are introduced through an overarching analysis of the work of performance artist Marina Abramovi?? and philosopher Jacques Derrida who, it is argued, provide a new model of telepathy as an art practice. In addition, the thesis argues that telepathy is an often suppressed thematic in art which may not appear to directly address it, and uses the work on the Wilsons, Treister and Hiller to re-look at other 20th Century artists and artistic themes in the light of the conclusions it draws on telepathy and art. Walter Benjamin greatly admired the Surrealists, but had virtually no time for their interest in telepathy, hypnosis and psi. Together with positive materialist misappropriations of Adorno???s Thesis Against Occultism, artistic and theoretical work with telepathy and psi has been sidelined from other important themes in art and critical theory, all of which telepathy and psi illuminate, energise and empower. The art of the author and other more recognised and established artists can be seen to work with telepathy in ways that flow into and reinforce the grain of progressive leftist practice and aesthetics. Women???s work with telepathy should be considered as important as women???s work with sexuality. Women, sexuality, Otherness, liminality, spirituality, telepathy, trauma, healing, radical politics, and other taboo areas of patriachal codes, were adandoned by macho participants of fluxus and Conceptual art. The recent conceptual and performance tilt in contemporary art sheds new light on the problem of working within and developing an effective and dynamic lineage of telepathy in post 60s art as well as early modern art movements. Contemporary developments in science, engineering, biology, psychoanalysis, warfare, popular culture and sociology show the wider relevance of discourse on telepathy. There is much at stake for visual art, aesthetics and visuality in representing, celebrating and interrogating the theme of psi and telepathy in current practice and art history. Artists??? work with telepathy and psi, although not always explicitly psychological, political or aesthetic, is often very psychologically, politically and aesthetically effective.
82

Performance-Driven Microfabrication-Oriented Methodology for MEMS Conceptual Design with Application in Microfluidic Device Design

Deng, Y.-M., Lu, Wen Feng 01 1900 (has links)
Performance and manufacturability are two important issues that must be taken into account during MEMS design. Existing MEMS design models or systems follow a process-driven design paradigm, that is, design starts from the specification of process sequence or the customization of foundry-ready process template. There has been essentially no methodology or model that supports generic, high-level design synthesis for MEMS conceptual design. As a result, there lacks a basis for specifying the initial process sequences. To address this problem, this paper proposes a performance-driven, microfabrication-oriented methodology for MEMS conceptual design. A unified behaviour representation method is proposed which incorporates information of both physical interactions and chemical/biological/other reactions. Based on this method, a behavioural process based design synthesis model is proposed, which exploits multidisciplinary phenomena for design solutions, including both the structural components and their configuration for the MEMS device, as well as the necessary substances for the chemical/biological/other reactions. The model supports both forward and backward synthetic search for suitable phenomena. To ensure manufacturability, a strategy of using microfabrication-oriented phenomena as design knowledge is proposed, where the phenomena are developed from existing MEMS devices that have associated MEMS-specific microfabrication processes or foundry-ready process templates. To test the applicability of the proposed methodology, the paper also studies microfluidic device design and uses a micro-pump design for the case study. / Singapore-MIT Alliance (SMA)
83

A conceptual model to estimate the nitrogen requirement of corn (Zea mays L.)

Lopez Collado, Catalino Jorge 25 April 2007 (has links)
The objectives of this work were to evaluate the vegetative parameters used to estimate crop N demand and to estimate the accuracy and precision of the conceptual model of fertilization using an error propagation method. Corn plants were collected throughout the entire crop life cycle to determine the fresh and dry weight of the aboveground biomass and roots, root index, plant height, and corn grain yield. Three experiments were conducted, two under field conditions and one under greenhouse conditions. In the first field experiment in 2002, three sites were selected. The first site was the Texas A&M University (TAMU) Agricultural Experiment Station Research Farm in which a Ships clay soil was used. The second site was a cooperative farmer's land on a Weswood silt loam soil in Burleson County. These first two sites used Pioneer 32R25 as the corn hybrid. The third site was also a Ships soil in the TAMU Farm, but Dekalb 687 was the corn variety. In 2003, the second experiment was on a Ships soil in the field of TAMU Farm, and the third experiment was conducted in a greenhouse using Ships and Weswood soil. No differences in the root index and harvest index were observed, even when the Dekalb 687 hybrid was included. Variations in plant N concentration, moisture content, and yield were noted, but followed predictable patterns with time over the season. These parameters were consistent throughout the entire life cycle of the crop. The linear relationship between the fresh weight of aboveground biomass and fresh weight of roots was R2 = 0.92, the moisture content of corn plants over time was fit to a second grade polynomial with R2 = 0.98, and plant N content had a close linear relationship (R2=0.90) with the total plant dry weight, including roots, at harvest. The accuracy of the conceptual model was low under field conditions (55%), but high under greenhouse conditions (90%). Precision of the conceptual model was low both in the field (194%) and the greenhouse (115%) conditions.
84

Environmental Security : A conceptual investigating study

Sporring Jonsson, Elin January 2009 (has links)
The purpose of this thesis is to explore the concept of environmental security. A concept that have made way on to the international arena since the end of the Cold War, and have become of more importance since the 1990’s. The discussion regarding man-made environmental change and its possible impacts on the world is very topical; especially with the Nobel Peace Prize winners in 2007 the Intergovernmental panel on climate change (IPCC) and Al Gore.The concept of environmental security is examined through a conceptual investigating study. The reason for this type of study is due to the complexity of the concept and a hope to find a ‘best’ definition to it. A conceptual investigating study is said to help create order in an existing discussion of a social problem, hence the reason for it in this thesis. The outcome of this thesis is that it is near impossible to find a ‘best’ or one definition to the concept of environmental security and that another method to deal with the concept might have presented another result. / Syftet med denna uppsats är att undersöka konceptet environmental security. Detta koncept har gjort sin väg till ett internationellt erkännande sedan Kalla kriget, och har sedan 1990-talet blivit allt mer aktuellt. Diskussionen gällande människans inverkan på klimatförändringarna och klimathotet är ständigt aktuellt, i synnerhet med tanke på vinnarna av Nobels Freds Pris 2007, med Al Gore i spetsen.Konceptet environmental security är i denna uppsats undersökt genom en begreppsutredande studie. Anledningen till denna typ av studie är att konceptet är såpass komplext men även baserat på hoppet av att hitta en ’bästa’ möjliga definition. Begreppsutredande studier sägs kunna skapa ordning i en existerande diskussion vilket kan ses som den främsta anledningen valet av den i denna uppsats.Resultatet av studien och denna uppsats är att det är i stort sett omöjligt att etablera en bästa definition av begreppet environmental security, samt att en annan metod förmodligen hade presenterat ett annat resultat.
85

Meaning Construction: Cognitive Processes of Conceptual Interaction

Ran, Bing January 2007 (has links)
This thesis proposes a theoretical framework explaining cognitive processes of meaning construction through conceptual interactions. It was noted that while the nine models or theories (Fuzzy Sets, Selective Modification model, Amalgam theory, Concept Specialization model, Composite Prototype Model, Dual-Process model, Constraint model, CARIN model, and Coherence Theory) in literature on conceptual combination offered insights on the problem of how people understand conceptual combinations, most of them assumed a schematic representation of our knowledge of concepts. However, it is possible that our minds represent knowledge in less structured ways and that schematic structure may not necessarily play a role in making sense of conceptual combinations. In this thesis, I attempted to make fewer assumptions about how knowledge is represented to explain the cognitive processes of conceptual combinations. I assume that concepts are related to other concepts, and knowledge can be represented by associations among concepts. Based on this assumption, the meaning of a conceptual combination is constructed through interactions between these associated concepts. It is proposed that the cognitive processes involved in meaning construction start from a distinction between different roles each component concept plays (head or modifier), and then a system of associations are activated contingently, prototypically, and efficiently with the goal of forming a cognitive field (analytically represented as a closed cycle) to connect head and modifier in a balanced way. The balanced system of concepts is strengthened further by reconciling remaining tensions in the field. Experimental results confirmed that component concepts in a combination activate associations contingently, and prototypicality and balance are major factors influencing whether an association will be activated by the combination to construct the meaning. Head / Modifier and Novelty were also studied as moderating variables. The experimental results indicated that head is a stronger moderator for association activation than modifier, and novelty was not found to be a significant moderator in association activation. Implications of these findings are discussed and future research is identified.
86

Meaning Construction: Cognitive Processes of Conceptual Interaction

Ran, Bing January 2007 (has links)
This thesis proposes a theoretical framework explaining cognitive processes of meaning construction through conceptual interactions. It was noted that while the nine models or theories (Fuzzy Sets, Selective Modification model, Amalgam theory, Concept Specialization model, Composite Prototype Model, Dual-Process model, Constraint model, CARIN model, and Coherence Theory) in literature on conceptual combination offered insights on the problem of how people understand conceptual combinations, most of them assumed a schematic representation of our knowledge of concepts. However, it is possible that our minds represent knowledge in less structured ways and that schematic structure may not necessarily play a role in making sense of conceptual combinations. In this thesis, I attempted to make fewer assumptions about how knowledge is represented to explain the cognitive processes of conceptual combinations. I assume that concepts are related to other concepts, and knowledge can be represented by associations among concepts. Based on this assumption, the meaning of a conceptual combination is constructed through interactions between these associated concepts. It is proposed that the cognitive processes involved in meaning construction start from a distinction between different roles each component concept plays (head or modifier), and then a system of associations are activated contingently, prototypically, and efficiently with the goal of forming a cognitive field (analytically represented as a closed cycle) to connect head and modifier in a balanced way. The balanced system of concepts is strengthened further by reconciling remaining tensions in the field. Experimental results confirmed that component concepts in a combination activate associations contingently, and prototypicality and balance are major factors influencing whether an association will be activated by the combination to construct the meaning. Head / Modifier and Novelty were also studied as moderating variables. The experimental results indicated that head is a stronger moderator for association activation than modifier, and novelty was not found to be a significant moderator in association activation. Implications of these findings are discussed and future research is identified.
87

Conceptual Model Uncertainty in the Management of the Chi River Basin, Thailand

Nettasana, Tussanee 30 April 2012 (has links)
With increasing demand and pressures on groundwater resources, accurate and reliable groundwater prediction models are essential for sustainable groundwater management. Groundwater models are merely approximations of reality, and we are unable to either fully characterize or mathematically describe the true complexity of the hydrologic system; therefore, inherent in all models are varying degree of uncertainty. A robust management policy should consider uncertainties in both the imprecise nature of conceptual/numerical models and their parameters. This study addresses the critical question of whether the use of multiple conceptual models to explicitly account for conceptual model uncertainty improves the ability of the models to assist in management decisions. Twelve unique conceptual models, characterized by three alternative geological interpretations, two recharge estimations, and two boundary condition implementations, were formulated to estimate sustainable extraction rates from Thailand’s Thaphra Area, where increasing groundwater withdrawals may result in water level declination and saline water upconing. The models were developed with MODFLOW and calibrated using PEST with the same set of observed hydraulic head data. All of the models were found to reasonably produce predictions of the available heads data. To select the best among the alternative models, multiple criteria have been defined and applied to evaluate the quality of individual models. It was found that models perform differently with respect to different evaluation criteria, and that it is unlikely that a single inter-model comparison criterion will ever be sufficient for general use. The chosen alternative models were applied both individually and jointly to quantify uncertainty in the groundwater management context. Different model-averaging methods were assessed in terms of their ability to assist in quantifying uncertainty in sustainable yield estimation. The twelve groundwater simulation models were additionally linked with optimization techniques to determine appropriate groundwater abstraction rates in the TPA Phu Thok aquifer. The management models aim to obtain maximal yields while protecting water level decline. Despite similar performances among the calibrated models, total sustainable yield estimates vary substantially depending on the conceptual model used and range widely, by a factor of 0.6 in total, and by as much as a factor of 4 in each management area. The comparison results demonstrate that simple averaging achieves a better performance than formal and sophisticated averaging methods such as Maximum Likelihood Bayesian Model Averaging, and produce a similar performance to GLUE and combined-multiple criteria averaging methods for both validation testing and management applications, but is much simpler to implement and use, and computationally much less demanding. The joint assessment of parameter and conceptual model uncertainty was performed by generating the multiple realizations of random parameters from the feasible space for each calibrated model using a simple Monte Carlo approach. The multi-model averaging methods produce a higher percentage of predictive coverage than do any individual models. Using model-averaging predictions, lower optimal rates were obtained to minimize head constraint violations, which do not ensue if a single best model is used with parameter uncertainty analysis. Although accounting for all sources of uncertainty is very important in predicting environmental and management problems, the available techniques used in the literature may be too computationally demanding and, in some cases, unnecessary complex, particularly in data-poor systems. The methods presented here to account for the main sources of uncertainty provide the required practical and comprehensive uncertainty analysis and can be applied to other case studies to provide reliable and accurate predictions for groundwater management applications.
88

Formulation of an Integrated Robust Design and Tactics Optimization Process for Undersea Weapon Systems

Frits, Andrew P. 11 January 2005 (has links)
In the current Navy environment of undersea weapons development, the engineering aspect of design is decoupled from the development of the tactics with which the weapon is employed. Tactics are developed by intelligence experts, warfighters, and wargamers, while torpedo design is handled by engineers and contractors. This dissertation examines methods by which the conceptual design process of undersea weapon systems, including both torpedo systems and mine counter-measure systems, can be improved. It is shown that by simultaneously designing the torpedo and the tactics with which undersea weapons are used, a more effective overall weapon system can be created. In addition to integrating torpedo tactics with design, the thesis also looks at design methods to account for uncertainty. The uncertainty is attributable to multiple sources, including: lack of detailed analysis tools early in the design process, incomplete knowledge of the operational environments, and uncertainty in the performance of potential technologies. A robust design process is introduced to account for this uncertainty in the analysis and optimization of torpedo systems through the combination of Monte Carlo simulation with response surface methodology and metamodeling techniques. Additionally, various other methods that are appropriate to uncertainty analysis are discussed and analyzed. The thesis also advances a new approach towards examining robustness and risk: the treatment of probability of success (POS) as an independent variable. Examining the cost and performance tradeoffs between high and low probability of success designs, the decision-maker can make better informed decisions as to what designs are most promising and determine the optimal balance of risk, cost, and performance. Finally, the thesis examines the use of non-dimensionalization of parameters for torpedo design. The thesis shows that the use of non-dimensional torpedo parameters leads to increased knowledge about the scaleability of torpedo systems and increased performance of Designs of Experiments. The integration of these ideas concerning tactics, robust design with uncertainty, and non-dimensionalization of torpedo parameters has lead to the development of a general, powerful technique by which torpedo and other undersea weapon systems can be fully optimized, thereby increasing performance and decreasing the total cost of future weapon systems.
89

A Method for Aircraft Concept Exploration using Multicriteria Interactive Genetic Algorithms

Buonanno, Michael Alexander 28 November 2005 (has links)
The problem of aircraft concept selection has become increasingly difficult in recent years due to changes in the primary evaluation criteria of concepts. In the past, performance was often the primary discriminator whereas modern programs have placed increased emphasis on factors such as environmental impact, economics, supportability, aesthetics, and other metrics. The revolutionary nature of the vehicles required to simultaneously meet these conflicting requirements has prompted a shift from design using historical data regression techniques for metric prediction to the use of sophisticated physics-based analysis tools that are capable of analyzing designs outside of the historical database. The use of optimization methods with these physics-based tools, however, has proven difficult because of the tendency of optimizers to exploit assumptions present in the models and drive the design towards a solution which, while promising to the computer, may be infeasible due to factors not considered by the computer codes. In addition to this difficulty, the number of discrete options available at this stage may be unmanageable due to the combinatorial nature of the concept selection problem, leading the analyst to select a sub-optimum baseline vehicle. Some extremely important concept decisions, such as the type of control surface arrangement to use, are frequently made without sufficient understanding of their impact on the important system metrics due to a lack of historical guidance, computational resources, or analysis tools. This thesis discusses the difficulties associated with revolutionary system design, and introduces several new techniques designed to remedy them. First, an interactive design method has been developed that allows the designer to provide feedback to a numerical optimization algorithm during runtime, thereby preventing the optimizer from exploiting weaknesses in the analytical model. This method can be used to account for subjective criteria, or as a crude measure of un-modeled quantitative criteria. Other contributions of the work include a modified Structured Genetic Algorithm that enables the efficient search of large combinatorial design hierarchies and an improved multi-objective optimization procedure that can effectively optimize several objectives simultaneously. A new conceptual design method has been created by drawing upon each of these new capabilities and aspects of more traditional design methods. The ability of this new technique to assist in the design of revolutionary vehicles has been demonstrated using a problem of contemporary interest: the concept exploration of a supersonic business jet. This problem was found to be a good demonstration case because of its novelty and unique requirements, and the results of this proof of concept exercise indicate that the new method is effective at providing additional insight into the relationship between a vehicle's requirements and its favorable attributes.
90

Conceptual Knowledge of Evolution and Natural Selection: How Culture Affects Knowledge Aquisition

Gutierrez, Maria Del Refugio 2009 December 1900 (has links)
This study examined what effects, if any, cultural factors have on conceptual knowledge of evolutionary theory through natural selection. In particular, the study determines if Latino and non-Latino students differ in their misconceptions of natural selection and, if so, whether or not cultural factors could be the reason why such differences exist. A total of 1179 college students attending eight Hispanic-Serving Institutions in Texas participated in the study. The results revealed that the top two challenging natural selection concepts for students to comprehend were causes of phenotypic variation, i.e., mutations are intentional, and selective survival based on heritable traits. In addition, no statistical significant differences were found between the Latino and non-Latino students and the top four natural selection misconceptions between the groups were similar. Not even religion was found to directly contribute to evolutionary misconceptions; even though, it serves as the core of an individual’s beliefs system. However, traditional teaching methods, inadequately trained biology school teachers, lessons poor in content, insufficient teaching time, and lack of age appropriate tasks, as well as, poorly defined evolutionary terms are actually the main causes for evolutionary misconceptions.

Page generated in 0.0691 seconds