| 41. |
- Sznajdman, Jacob, 1983
(author)
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Some Analytic generalizations of the Briancon-Skoda Theorem
- 2010
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Licentiate thesis (other academic/artistic)abstract
- The Brian\c con-Skoda theorem appears in many variations in recent literature. The common denominator is that the theorem gives a sufficient condition that implies a membership $\phi\in \ideala^l$, where $\ideala$ is an ideal of some ring $R$. In the analytic interpretation $R$ is the local ring of an analytic space $Z$, and the condition is that $|\phi|\leq C|\ideala|^{N+l}$ holds on the space $Z$. The theorem thus relates the rate of vanishing of $\phi$ along the locus of $\ideala$ to actual membership of (powers of) the ideal. The smallest integer $N$ that works for all $\ideala \subset R$ and all $l\geq 1$ simultaneously will be called the Brian\c con-Skoda number of the ring $R$. The thesis contains three papers. The first one gives an elementary proof of the original Brian\c con-Skoda theorem. This case is simply $Z=\C^n$. The second paper contains an analytic proof of a generalization by Huneke. The result is also sharper when $\ideala$ has few generators if the geometry is not to complicated in a certain sense. Moreover, the method can give upper bounds for the Brian\c con-Skoda number for some varieties such as for example the cusp $z^p = w^q$. In the third paper non-reduced analytic spaces are considered. In this setting Huneke's generalization must be modified to remain valid. More precisely, $\phi$ belongs to $\ideala^l$ if one requires that $|L \phi| \leq C |\ideala|^{N+l}$ holds on $Z$ for a given family of holomorphic differential operators on $Z$. We impose the assumption that the local ring $\O_Z$ is Cohen-Macaulay for technical reasons.
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| 42. |
- Säfström, Ida, 1984
(author)
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Tensor Products of Highest Weight Representations and Skew-Symmetric Matrix Equations A+B+C=0
- 2010
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Licentiate thesis (other academic/artistic)abstract
- The question of characterizing the eigenvalues for the sum of two Hermitian matrices, was solved in 1999, after almost a century of efforts. The saturation conjecture for GL_C(n) was proven by Knutson and Tao, filling in the last gap in Horn’s conjecture. Under certain conditions, this problem is equivalent to decomposing the tensor product of two finite dimensional irreducible highest weight representations of GL_C(n). In the first part of this thesis we use the methods of moment maps and coadjoint orbits to find equivalence between the eigenvalue problem for skew-symmetric matrices and the decomposition of tensor products of irreducible highest weight representations of SO_C(2k). We characterize the eigenvalues in the cases k = 2,3, where we can take advantage of Lie algebra isomorphisms. In the second part, we consider irreducible, infinite dimensional, unitary highest weight representations of GL_C(n + 1) as representations on spaces of vector valued polynomials, and we find irreducible factors in the tensor product of two such representations.
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| 43. |
- Torfason, Asgeir B., 1972
(author)
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Investments in a long-term perpective - how a family company has built its assets
- 2010
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Licentiate thesis (other academic/artistic)abstract
- In this thesis the debate between the two regimes of historical cost accounting and fair value accounting is exemplified with observation of real estate valuation over time. The aim of the study is to contribute to the understanding of how different value concepts are of relevance in a real estate company. An explorative case study illustrates the different value concepts used for accounting and management in a family owned real estate company, the Kjellbergs. The rebuilding of Kvillestaden in Göteborg finished thirty years ago is analysed, presenting how the family company has built its assets over a long period of time. The study shows how contradicting accounting methods are used in an integrative accounting that presents different financial values built on personal values. A model of accounting communication is used to analyse significance and fidelity of each value concept. The financial value concepts identified for real estate are: investment value, book value, tax value and market value. Customer value is the operational focus area for the Kjellbergs and is based on the three personal values underpinning the management of the firm and the investment decisions. These personal values are identified in: well thought through operations, high quality assets and long-term ownership. A conclusion is drawn that the different value concepts are of relevance in an integrative manner. The integrative use of the different value concepts, financial and personal, is seen as the key success factor in the operations of the firm through eight decades. Another conclusion of the study is that different value concepts are relevant because of the strong twofold relation between the owner of the company and the buildings and their tenants on the one hand and on the other hand between the owner and the accounting and its external users such as municipalities and banks.
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| 44. |
- Wojciechowski, Adam, 1982
(author)
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On the optimization of opportunistic maintenance activities
- 2010
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Licentiate thesis (other academic/artistic)abstract
- Maintenance is a source of large costs; in the EU the maintenance costs amountto between 4% and 8% of the total sales turnover. Opportunistic maintenance is anattempt to lower the maintenance cost by considering the failure of onecomponent as an opportunity to replace yet non-failed components in order toprevent future failures. At the time of failure of one component, a decision is to be made on which additional components toreplace in order to minimize the expected maintenance cost over a planningperiod.This thesis continues the work of Dickman et. al. (1991) and Andreasson (2004) on the opportunistic replacement problem. In Paper I, we show thatthe problem with time-dependent costs is NP-hard and present a mixed integerlinear programming model for the problem. We apply the model to problems withdeterministic and stochastic component lives with data originating from theaviation and wind power industry. The model is applied in a stochastic settingby employing the expected values of component lives. In Paper II, a first steptowards a stochastic programming model that considers components with uncertain lives istaken by extending the problem to allow non-identical lives for component individuals.This problem is shown to be NP-hard even with time-independent costs. We present amixed integer linear programming model of the problem. The solution time of the model is substantially reduced compared to the model presented in Andreasson (2004). In Paper III, we then study the opportunisticreplacement problem with uncertain component lives and present a two-stagestochastic programming approach. We present a deterministic equivalent model anddevelop a decomposition method. Numerical studies on the same data as in Paper I from the aviation and wind power industry show that the stochastic programming approachproduces maintenance decisions that are on average less costly than decisions obtained from simple maintenance policies and the approach used in Paper I. The decomposition method requires less CPU-time than solving the deterministic equivalent on three out of four problems.
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| 45. |
- Wängqvist, Maria, 1977
(author)
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To be whatever you want to be, you still need to know what that is: Identity development in emerging adulthood
- 2010
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Licentiate thesis (other academic/artistic)abstract
- DEGREE OF LlCENTIATE IN PSYCHOLOGY abstract Wängqvist, M (2010). To be whatever you want to be, you still need to know what that is: Identity development in emerging adulthood. Department of Psychology, University of Gothenburg, Sweden. In western industrialized societies an expanded period of identity exploration and uncertainty of ten follows adolescence and precedes the entry into adult roles. This period has been labeled emerging adulthood and identity exploration is described as an important aspect of this stage in life. In this thesis two empirical studies that deal with emerging adults' identity development are presented. The objective of Study I was to examine the identity deve10pment of emerging adults in Sweden in order to discover how identity issues concerning love, work and family are dealt with, and how this is re1ated to their experiences with love and work. The study group comprised 136 24- to 26-year-olds (68 women and 68 men). The results revealed that less than half of the emerging adults had reached identity defining commitments subsequent to a period of active exploration of alternatives (identity achievement) and that there were differences between women's and men's positions in the identity formation process. Women were more likely "than men to have made commitments subsequent to a period of active exploration of alternatives (identity achievement), whereas men were more likely than women to lack identity defining commitments in combination with a lack of past or present active exploration (identity diffusion). AIso, the position in the identity formation process was different for different life-areas for the men, whereas for the women identity achievement was consistently the most common. Further, the results showed a relationship between identity formation and aspects of love and work. Those who had made identity-defining commitments after a period of exploration (identity achievement) were more likely to be in a long-term romantic relationship than those who had engaged in neither the exploration of, nor commitment to identity issues (identity diffusion). Additionally, the participants in the identity diffusion group were less likely to be enrolled in university education, whereas this was common in the group with identity achievement. In Study II the aim was to explore the relationship between identity formation, psychological symptoms and identity distress. The study group was the same as for Study I. Individuals who were involved in a process of active exploration (moratorium) reported more and higher levels of psychological symptoms, as weIl as higher levels of distress over identity issues. A mediational mode1 was tested and the results implied that the association between identity formation and psychological symptoms may be mediated by distress over identity issues. Key Words: Identity Development, Emerging Adulthood, Gender Differences, Occupational contexts, Romantic Relationships, Family Relationships, Psychological Symptoms, Identity Distress ISSN llOl-718X ISRN GUjPSYKjAVH--229--SE Maria Wängqvist, Department of Psychology, University of Gothenburg, Box 500, 405 30 Gothenburg, Phone: + 46317864262, E-mail: maria.wangqvist@ps)..gu.se
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| 46. |
- Öhman, Lisa, 1978
(author)
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Voice Identification: The effect of Age and Presentation Format
- 2010
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Licentiate thesis (other academic/artistic)abstract
- Degree of Licentiate in Psychology Abstract Öhman, L. (2010). Voice ldentification: The Effect of Age and Presentation Format. Department of Psychology, University of Gothenburg, Sweden In some criminal cases the victim's or witness's memory of the perpetrator's voice may be an important clue and therefore have a vital role in both the investigative phase and in court. Examples of such situations are crimes committed under conditions of darkness or by disguised perpetrators, such as hooded rape or robbery. Another category is crimes committed over the phone such as obscene phone calls, fraud calls and other threatening phone calls. Although earwitness observations are not as unusual as one may think, witnesses' memory for voices is, compared to eyewitness identification, a much neglected research area. People of all ages can become victims of and/or witnesses to a crime, therefore it is important to assess voice identification performance for different age-groups. In the current thesis children and adults were tested with respect to their ability to identify an unfamiliar voice (Study I). The common use of mobile phones in today' s society is mirrored by the high number of criminal cases where mobile phones are involved. Hence, the present thesis investigates the effect of being exposed to a voice via mobile phone on voice identification accuracy (Study II). Both studies used the same setup, which included the exposure of an unfamiliar voice for 40 seconds, and a seven-voice lineup after a two week delay. The aim of Study I was to explore the earwitness performance of children aged 7-9 (N = 95) and 11-13 (N = 78), and adults (N = 91). Half of the participants were exposed to a target-present lineup (T-P), and the other half to a target-absent lineup (T-A). For both types oflineups the participants performed poorly. In the T-P condition only the 11-l3-year olds (with 27 % correct identifications) performed above chance level (12.5%, 8 possible alternatives). Furthermore, in the T-A condition all age-groups showed a high wiIlingness to make an identification (overall mean = 53%). For both groups of children, voice identification co-varied significantly with speaking rate and pitch level, as did pitch variation for the youngest children. Neither factor correlated significantly with the aduIts' identifications. The aim of Study II was to investigate the influence of presentation format (direct recorded voices vs. mobile phone recorded voices) on voice recognition accuracy. The participating adults (N = 174) were assigned randomly to one of the four conditions (Initial exposure: direct vs. mobile phone recorded voice; Lineup presentation: direct vs. mobile phone recorded voices). The overall accuracy for correct identification was 12.7%, which is expected by chance (12.5%), and more than half of the participants (57%) made a false identification. Further, the resuIts did not reveal any significant effect of presentation format or lineup format. These results suggest that the detrimental effect on voice recognition suggested by the poorer sound quaIity of mobile phone recordings is minimal. They also indicate that there is no benefit from conducting a mobile phone recorded lineup, ifthe voice is originally heard over a mobile phone. In sum, the effect of age and presentation format was found to be very small. However, the overall conclusion that follows from the present thesis is that earwitnesses seem to be poor at making a correct decision when confronted with a voice lineup. Actors in the legal system should therefore treat voice identification evidence with caution. Keywords: earwitness, voice identification, voice lineup, children, presentation format, mobile phone Lisa Öhman, Department ofPsychology, University of Gothenburg, P.O. Box 500, 405 30 Gothenburg, Sweden. Phone:+46317861934, E-mail: lisa.ohman@psy.gu.se ISSN l101-718X ISRN GU/PSYKJAVH--238--SE
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