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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.
1

Forced two layer beta-plane quasi-geostrophic flow

Onica, Constantin 12 April 2006 (has links)
We consider a model of quasigeostrophic turbulence that has proven useful in theoretical studies of large scale heat transport and coherent structure formation in planetary atmospheres and oceans. The model consists of a coupled pair of hyperbolic PDE’s with a forcing which represents domain-scale thermal energy source. Although the use to which the model is typically put involves gathering information from very long numerical integrations, little of a rigorous nature is known about long-time properties of solutions to the equations. In the first part of my dissertation we define a notion of weak solution, and show using Galerkin methods the long-time existence and uniqueness of such solutions. In the second part we prove that the unique weak solution found in the first part produces, via the inverse Fourier transform, a classical solution for the system. Moreover, we prove that this solution is analytic in space and positive time.
2

The influence of hedonic and utilitarian purchase motivation on assortment size choice

Whitley, Sarah Catherine 30 June 2018 (has links)
The present research examines how hedonic and utilitarian purchase motivations influence consumers’ perceptions of their product preferences and the resulting number of options they wish to consider when making a purchase. Experimental study results show that consumers choose to review larger assortments when their purchase motivation is hedonic rather than when their purchase motivation is utilitarian. This effect occurs because consumers with hedonic purchase motivations perceive their product preferences as highly unique compared to consumers with utilitarian purchase motivations. Higher perceived preference uniqueness increases the difficulty consumers anticipate in finding a preference-matching product, resulting in an expansion of the number of product alternatives to review. Further supporting the perceived preference uniqueness account, the documented effect is attenuated when a social similarity priming task is employed and when product assortments are customized based on consumers’ personal preferences. Additional alternative explanations are explored. These findings provide additional evidence on the distinction between hedonic and utilitarian purchase motivations, their impact on perceived preference uniqueness, and their implications for consumer decision making via assortment size choice.
3

Notes on Uniqueness of Meromorphic Functions

Lü, W., Cao, J. 01 December 2006 (has links)
In this paper, we study the problem of uniqueness on meromorphic functions involving in differential polynomials and obtain some results which extend and improve the theorems of M. Fang and W. Hong et al.
4

From quantum many body systems to nonlinear Schrödinger Equations

Xie, Zhihui 06 November 2014 (has links)
The derivation of nonlinear dispersive PDE, such as the nonlinear Schrödinger (NLS) or nonlinear Hartree equations, from many body quantum dynamics is a central topic in mathematical physics, which has been approached by many authors in a variety of ways. In particular, one way to derive NLS is via the Gross-Pitaevskii (GP) hierarchy, which is an infinite system of coupled linear non-homogeneous PDE. In this thesis we present two types of results related to obtaining NLS via the GP hierarchy. In the first part of the thesis, we derive a NLS with a linear combination of power type nonlinearities in R[superscript d] for d = 1, 2. In the second part of the thesis, we focus on considering solutions to the cubic GP hierarchy and we prove unconditional uniqueness of low regularity solutions to the cubic GP hierarchy in R[superscript d] with d ≥ 1: the regularity of solution in our result coincides with known regularity of solutions to the cubic NLS for which unconditional uniqueness holds. / text
5

Airborne Gravity Gradient, Magnetic and VLF datasets : Case studies of modelling, inversion and interpretation

Abtahi, Sayyed Mohammad January 2016 (has links)
Northern Sweden is one of the largest hosts for mineral resources in Europe and always has been an interesting area for researchers from various disciplines of Earth sciences. This dissertation is a comprehensive summary of three case study papers on airborne VLF, gravity gradient and magnetic data in the area. In the first paper, tensor VLF data is extracted from an old data set which contains only the total and the vertical magnetic components. The anomalous part of the horizontal magnetic field components is computed by a Hilbert transform of the vertical magnetic field. The normal part of the horizontal magnetic field component is computed as a function of total, vertical and anomalous part of horizontal magnetic fields. The electric field is also calculated for TE mode and impedance tensor and apparent resistivity are computed. In addition tippers are calculated for two transmitters and inverted by a 3D inversion algorithm. Comparison of the estimated model and geology map of bedrock shows that lower resistivity zones are correlated with mineralizations. The second paper deals with the internal consistency of airborne gravity gradient data. The six components of the data are estimated from a common potential function. It is shown that the data is adequately consistent but at shorter land clearances the difference between the estimated data and the original data is larger. The technique is also used for computing the Bouguer anomaly from terrain corrected FTG data. Finally the data is inverted in 3D, which shows that the estimated density model in shallow depth is dominated by short wave length features. Inversion of TMI data is the topic of the third paper where a new type of reference model for 3D inversion of magnetic data is proposed by vertically extending the estimated magnetization of a 2D terrain magnetization model. The final estimated 3D result is compared with the magnetization model where no reference model is used. The comparison shows that using the reference model helps the high magnetization zones in the estimated model at shallow depths to be better correlated with measured high remanent magnetization from rock samples. The high magnetization zones are also correlated with gabbros and volcanic metasediments.
6

Theories on Auctions with Participation Costs

Cao, Xiaoyong 14 January 2010 (has links)
In this dissertation I study theories on auctions with participation costs with various information structure. Chapter II studies equilibria of second price auctions with differentiated participation costs. We consider equilibria in independent private values environments where bidders? entry costs are common knowledge while valuations are private information. We identify two types of equilibria: monotonic equilibria in which a higher participation cost results in a higher cutoff point for submitting a bid, and neg-monotonic equilibria in which a higher participation cost results in a lower cutoff point. We show that there always exists a monotonic equilibrium, and further, that the equilibrium is unique for concave distribution functions and strictly convex distribution functions with some additional conditions. There exists a neg-monotonic equilibrium when the distribution function is strictly convex and the difference of the participation costs is sufficiently small. We also provide comparative static analysis and study the limit status of equilibria when the difference in bidders' participation costs approaches zero. Chapter III studies equilibria of second price auctions when values and participation costs are both privation information and are drawn from general distribution functions. We consider the existence and uniqueness of equilibrium. It is shown that there always exists an equilibrium for this general economy, and further there exists a unique symmetric equilibrium when all bidders are ex ante homogenous. Moreover, we identify a sufficient condition under which we have a unique equilibrium in a heterogeneous economy with two bidders. Our general framework covers many relevant models in the literature as special cases. Chapter IV characterizes equilibria of first price auctions with participation costs in the independent private values environment. We focus on the cutoff strategies in which each bidder participates and submits a bid if his value is greater than or equal to a critical value. It is shown that, when bidders are homogenous, there always exists a unique symmetric equilibrium, and further, there is no other equilibrium when valuation distribution functions are concave. However, when distribution functions are elastic at the symmetric equilibrium, there exists an asymmetric equilibrium. We find similar results when bidders are heterogenous.
7

The Relationship among Outsourcing Management and Outsourcing Performance

Ho, Mei-Ling 30 June 2008 (has links)
By means of collecting the outsourcing experiences of different companies for example, the main topic of the study is to discuss the relationship among outsourcing management (Commitment-Based, Productivity-Based, Complained-Based and Collaborative-Based ) and outsourcing performance and the confounding effect of outsourcing job value and uniqueness on the relationships among the above variables. We hope that the findings of this study can be of the references for the companies to implement the outsourcing. The questionnaire survey was adopted for the study. The samples were collected through the staff of different companies who manage the outsourcing projects for the companies. There were 220 questionnaires totally being released, 101 questionnaires were returned and 76 of them were valid samples. Through statistics analysis, the main results of the study are¡G 1. The Complained-Based and Productivity-Based are the most common ways for the companies to adopt in outsourcing management, and the Commitment-Based is the least way to be adopted to manage outsourcing, especially in the financial banking industry, we got such kind of findings. As for the outsourcing performance, almost all the companies we surveyed are satisfied with it and with no significant difference among different companies. And the different industries affect the value and uniqueness of outsourcing job, particularly, the value of outsourcing job of financial banking industry is higher than other industries. 2. The Collaborative-Based outsourcing management has positively correlations not only with outsourcing effectiveness but also with the overall outsourcing performance and affectes them in a positive way. At the same time, the collaborative-based management also affects outsourcing efficiency. And we also found that the Commitment-Based outsourcing management affects the outsourcing efficiency and the overall outsourcing performance in a negative way. 3. The value of outsourcing job has positive confounding effect on the relationship between the Collaborative-Based outsourcing management and the outsourcing efficiency. We found that as for the high value of outsourcing jobs, the companies that adopted more Collaborative-Based management resulted in more efficient outsourcing outcome. Key Words¡GOutsourcing, Outsourcing Management, Outsourcing Performance, Value, Uniqueness
8

Psychological well-being and uniqueness seeking behaviour / Colleen Ashleigh La

Law, Colleen Ashleigh January 2005 (has links)
The purpose of this study was to investigate the relationship between psychological wellbeing and uniqueness seeking behaviour. Early research in psychology has primarily followed a pathogenic approach, focusing on the way in which stressful life events predispose an individual to negative health outcomes. More recently a number of theorists and researchers have adopted a salutogenic approach, which refers to the origins of physical and mental health and explores the factors that assist individuals to maintain psychological and physical well-being in the face of stressful situations (Antonovsky. 1979 & 1987; Pallant & Lae, 2002). Uniqueness seeking is a relatively new construct that seems to be part of the repertoire of strengths an individual uses to improve psychological well-being. Theorists postulate that moderate needs for uniqueness are experienced more positively than extremely high or extremely low needs for uniqueness. (Lynn & Snyder, 2002 and Snyder & Fromkin, 1980). The study aims to determine the difference in psychological well-being in individuals with varying needs for uniqueness; to explore the perceptions and subjective experience of uniqueness seeking; and to explore the role uniqueness seeking plays in consumer behaviour. The psychometric properties of two scales measuring uniqueness will also be investigated, as they have not previously been used in a South African sample. To achieve these aims an availability sample of 187 students completed self-report measures of psychological well-being and uniqueness seeking behaviour namely, the Orientation to Life Scale (Antonovsky. 1987), the Self Attributed Need for Uniqueness Scale (Lynn and Harris, 1997b) and the Desire for Unique Consumer Products Scale (Lynn and Harris, 1997a). Sixteen of these students participated in focus groups in order to explore the participants' subjective experience of being unique. A further 13 participants took part in focus groups in order to explore the role uniqueness seeking plays in consumer behaviour. The measures were found to be reliable in this particular group and the means and standard deviations calculated were comparable with those mentioned in literature. No direct relationship between psychological well-being and uniqueness seeking was found, nor was it found that differences in psychological well-being exist between individuals with a moderate sense of uniqueness and individuals with a high or low sense of uniqueness. Individuals perceive uniqueness to be a quality that emerges naturally through the expression of the self and that actively seeking to be unique or not is rather due to a poor self-image. It was further found that individuals would go to some length to protect their sense of uniqueness, that most individuals preferred a sense of moderate uniqueness to either extremely high or extremely low sense of uniqueness, and that most individuals are satisfied with their level of uniqueness. Individuals described feeling happy and more confident when they perceived themselves to be unique. These individuals believe that the stage of life they are in and significant others play a role in determining the way in which uniqueness will have meaningful expression for them. Uniqueness seeking does not play as big a role in consumer behaviour as was expected, however, it does influence the consumption of consumer goods to a certain extent. It is therefore concluded that uniqueness seeking influences psychological well-being indirectly by the relationship it has with self-image. self-identity, self-confidence, group identifications, and subjective happiness. These findings have implications for future research in that the need for a valid and reliable instrument measuring uniqueness for use in South African samples is highlighted. The findings further clarify the uniqueness seeking construct thus contributing to the literary database of constructs that play a role in psychological well-being. / Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2006.
9

Savo unikalumo išgyvenimas psichoterapinėje grupėje / The phenomenon of uniqueness in a psychotherapy group

Tomkevičienė, Raimonda 23 June 2014 (has links)
Savo unikalumo išgyvenimas psichoterapinėje grupėje Šiame magistro darbe buvo tiriamas savo unikalumo išgyvenimo psichoterapinėje grupėje fenomenas. Įvadinėje dalyje į unikalumo fenomeną buvo pažvelgta iš filosofinių (S.Kierkegaardo, M.Heideggerio, M.Buberio, P.Tilicho) ir psichologinių (G.W.Allporto, C.R.Rogerso, S.M.Jourardo, J.Bugentalio, V.Franklio, A.R.Beisserio) idėjų perspektyvos. Buvo siekiama išsiaiškinti, kaip savo unikalumas patiriamas konkrečioje psichoterapinėje grupėje ir apibrėžti unikalumo fenomeną konkrečiai tiriamųjų grupei. Tyrime buvo naudojamas fokusinių grupių metodas. Fokusinė grupės buvo organizuojamos trumpalaikių psichoterapinių grupių kontekste. fokusinėse grupėse dalyvavo 13 žmonių: 11 moterų ir 2 vyrai. Buvo surengtos 2 fokusinės grupės, kurias pagal iš anksto paruoštą planą vedė moderatorius – šio darbo autorė. Gauti duomenys buvo apdoroti A.Giorgi fenomenologinės analizės metodo pagalba. Sudaryti 10 specifinių situacinių savo unikalumo fenomeno apibrėžimų, kuriais remiantis buvo suformuluoti 2 bendri galutiniai fenomeno apibrėžimai. Šio tyrimo rezultatai parodė, kad: 1)savo unikalumo išgyvenimas psichoterapinėje grupėje yra sudėtingas fenomenas, pasižymintis didele pasireiškimų įvairove; 2)savo unikalumo patyrimas psichoterapinėje grupėje glaudžiai susijęs su universalumo patyrimu: savo unikalumas išgyvenamas kartu su universalumu su grupės dalyviais arba tuoj po jo; 3)savo unikalumo patyrimas trumpalaikėje psichoterapinėje grupėje yra... [toliau žr. visą tekstą] / The Phenomenon of Uniqueness in a Psychotherapy Group The phenomenon of uniqueness in a psychotherapy group was studied in his master‘s degree work. Introduction was dedicated to review the human relationship phenomenon from the philosophical (S.Kierkegaard, M.Heidegger, M.Buber, P.Tilich) and psychological (G.W.Allport, C.R.Rogers, S.M.Jourard, J.Bugental, V.Frankl, A.R.Beisser) perspective. The aim of this work was to explore in what way the phenomenon of uniqueness is experienced in a certain psychotherapy group and define the phenomenon of uniqueness for the certain research group. The method of focus group was used in this research. Focus groups were organized in the context of short-term psychotherapy groups. 13 persons were participating in the focus groups: 11 women and 2 men. 2 focus groups were created, which were managed by the author of this study based on provided plan. The results were processed using A.Giorgi phenomenal method. 10 specific situational definitions of the phenomenon of uniqueness were created, which were used to formulate two ultimate definitions of the phenomenon. Results of the study revealed, that: 1) the phenomenon of uniqueness in a psychotherapy group is complex phenomenon, characterised by large diversity of manifestations; 2) the phenomenon of uniqueness in a psychotherapy group is closely related to universality experience: the uniqueness is experienced together with the universality of the group‘s participants or immediately after it... [to full text]
10

Psychological well-being and uniqueness seeking behaviour / Colleen Ashleigh La

Law, Colleen Ashleigh January 2005 (has links)
The purpose of this study was to investigate the relationship between psychological wellbeing and uniqueness seeking behaviour. Early research in psychology has primarily followed a pathogenic approach, focusing on the way in which stressful life events predispose an individual to negative health outcomes. More recently a number of theorists and researchers have adopted a salutogenic approach, which refers to the origins of physical and mental health and explores the factors that assist individuals to maintain psychological and physical well-being in the face of stressful situations (Antonovsky. 1979 & 1987; Pallant & Lae, 2002). Uniqueness seeking is a relatively new construct that seems to be part of the repertoire of strengths an individual uses to improve psychological well-being. Theorists postulate that moderate needs for uniqueness are experienced more positively than extremely high or extremely low needs for uniqueness. (Lynn & Snyder, 2002 and Snyder & Fromkin, 1980). The study aims to determine the difference in psychological well-being in individuals with varying needs for uniqueness; to explore the perceptions and subjective experience of uniqueness seeking; and to explore the role uniqueness seeking plays in consumer behaviour. The psychometric properties of two scales measuring uniqueness will also be investigated, as they have not previously been used in a South African sample. To achieve these aims an availability sample of 187 students completed self-report measures of psychological well-being and uniqueness seeking behaviour namely, the Orientation to Life Scale (Antonovsky. 1987), the Self Attributed Need for Uniqueness Scale (Lynn and Harris, 1997b) and the Desire for Unique Consumer Products Scale (Lynn and Harris, 1997a). Sixteen of these students participated in focus groups in order to explore the participants' subjective experience of being unique. A further 13 participants took part in focus groups in order to explore the role uniqueness seeking plays in consumer behaviour. The measures were found to be reliable in this particular group and the means and standard deviations calculated were comparable with those mentioned in literature. No direct relationship between psychological well-being and uniqueness seeking was found, nor was it found that differences in psychological well-being exist between individuals with a moderate sense of uniqueness and individuals with a high or low sense of uniqueness. Individuals perceive uniqueness to be a quality that emerges naturally through the expression of the self and that actively seeking to be unique or not is rather due to a poor self-image. It was further found that individuals would go to some length to protect their sense of uniqueness, that most individuals preferred a sense of moderate uniqueness to either extremely high or extremely low sense of uniqueness, and that most individuals are satisfied with their level of uniqueness. Individuals described feeling happy and more confident when they perceived themselves to be unique. These individuals believe that the stage of life they are in and significant others play a role in determining the way in which uniqueness will have meaningful expression for them. Uniqueness seeking does not play as big a role in consumer behaviour as was expected, however, it does influence the consumption of consumer goods to a certain extent. It is therefore concluded that uniqueness seeking influences psychological well-being indirectly by the relationship it has with self-image. self-identity, self-confidence, group identifications, and subjective happiness. These findings have implications for future research in that the need for a valid and reliable instrument measuring uniqueness for use in South African samples is highlighted. The findings further clarify the uniqueness seeking construct thus contributing to the literary database of constructs that play a role in psychological well-being. / Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2006.

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