We present limit theory for tests of homogeneity for finite mixture models. More specifically, we derive the asymptotic distribution of certain random quantities used for testing that a mixture of two distributions is in fact just a single distribution. Our methods apply to cases where the mixture component distributions come from one of a wide class of one-parameter exponential families, both continous and discrete. We consider two random quantities, one related to testing simple hypotheses, the other composite hypotheses. For simple hypotheses we consider the maximum of the standardised score process, which is itself a test statistic. For composite hypotheses we consider the maximum of the efficient score process, which is itself not a statistic (it depends on the unknown true distribution) but is asymptotically equivalent to certain common test statistics in a certain sense. We show that we can approximate both quantities with the maximum of a certain Gaussian process depending on the sample size and the true distribution of the observations, which when suitably normalised has a limiting distribution of the Gumbel extreme value type. Although the limit theory is not practically useful for computing approximate p-values, we use Monte-Carlo simulations to show that another method suggested by the theory, involving using a Studentised version of the maximum-score statistic and simulating a Gaussian process to compute approximate p-values, is remarkably accurate and uses a fraction of the computing resources that a straight Monte-Carlo approximation would.

<p>What do teenagers recount about themselves and their interpretation of life and values, and what characterises individual teenagers’ perceptions and statements? What is the relation between teenagers’ life interpretation and values and social circumstances? What challenges to school religious education do the teenagers’ perceptions and statements represent? These questions are central to the study Icelandic Teenagers’ Life Interpretation and Values.</p><p>The purpose of the study was to investigate some central elements in teenagers’ life interpretation so as to discuss the results in terms of social circumstances in Iceland and of school religious education. The background is that Icelandic society, having been relatively homogeneous, has changed during the past few years with increased plurality.</p><p>The material the study was based on consists of interviews with Icelandic teenagers. In four articles included in the thesis different parts of the material collected are interpreted using a hermeneutic approach. The main result showed that the teenagers were in a field of tension between homogeneity and plurality on the one hand and security and insecurity on the other. The main trends in the material indicate a common reference framework at the same time as plurality emerges in the teenager’s verbal expressions; and while most spoke of their happiness and security, there was also awareness of the risk and threat that can transform the situation.</p><p>The material exhibited greater variation within each school than between schools. This suggests the effect of plurality on the younger generation in Iceland. Given this variation among individuals it is urgent to find an approach to religious education that takes greater account of the different pupils’ backgrounds, personal experience and existential questions.</p>

Africa has during the past decades experienced vast difficulties in inducing greater levels of economic growth, which in turn has stirred intensive debates in an attempt to unveil its causes. A dawning debate to surface during recent years places corruption as a potent obstacle to impede and dent African economic progress. Embracing a theoretical and regression analysis, this thesis sets out to unravel the causes of African corruption, its implications, and its effects upon the economic standards of a number of selected countries. The findings reveal that corruption, amid all time-periods analyzed, discloses a strong deleterious impact upon GNI per capita primarily by damaging and undermining the African insti-tutional framework, which in turn is unable to function optimally. The outcome is that less economic progress [and thus lower levels of income] is being generated as resources are allocated and squandered in a non-optimal way. It is also substantiated that Protestantism and a high degree of homogeneity are factors that exercise a positive influence upon corruption and economic standards. The thesis finally illuminates the intricate and ubiquitous impediments that obscure Africa’s economic progress. It is concluded that inept governments and institutions too often lie at the core of the quandary. The current standard of Africa’s governments and institutions thus often leave much to be desired.

What do teenagers recount about themselves and their interpretation of life and values, and what characterises individual teenagers’ perceptions and statements? What is the relation between teenagers’ life interpretation and values and social circumstances? What challenges to school religious education do the teenagers’ perceptions and statements represent? These questions are central to the study Icelandic Teenagers’ Life Interpretation and Values. The purpose of the study was to investigate some central elements in teenagers’ life interpretation so as to discuss the results in terms of social circumstances in Iceland and of school religious education. The background is that Icelandic society, having been relatively homogeneous, has changed during the past few years with increased plurality. The material the study was based on consists of interviews with Icelandic teenagers. In four articles included in the thesis different parts of the material collected are interpreted using a hermeneutic approach. The main result showed that the teenagers were in a field of tension between homogeneity and plurality on the one hand and security and insecurity on the other. The main trends in the material indicate a common reference framework at the same time as plurality emerges in the teenager’s verbal expressions; and while most spoke of their happiness and security, there was also awareness of the risk and threat that can transform the situation. The material exhibited greater variation within each school than between schools. This suggests the effect of plurality on the younger generation in Iceland. Given this variation among individuals it is urgent to find an approach to religious education that takes greater account of the different pupils’ backgrounds, personal experience and existential questions.

Despite ample research showing the importance of corporate reputation in recruiting, knowledge about how companies work with employer branding is still limited. This first academic study in this topic is based on a comprehensive empirical data set systematized to a description of employer branding using a grounded theory approach. The description illustrates a process with three phases: brand input, brand support, and brand evaluation. Each phase is related to the messages enclosed in the brand. A comparative analysis of the empirical description and marketing literature shows that the underlying reasoning in branding at the labor market is quite similar to branding at the customer market. However, several important differences were also highlighted, indicating that employer branding is a multi-disciplinary phenomenon. The most surprising difference is a widespread homogeneity in the companies’ employer branding. This contrasts the emphasis on uniqueness in the marketing literature. A further analysis of this finding generated four homogenizing dimensions: time, industry, geography and corporate demographics. Each contains a number of corporate populations with companies similar in the dimension’s point of reference. Since the dimensions are not specific for the labor market a further analysis of the theoretical arguments for heterogeneity and homogeneity was motivated. This shows that there are economic as well as social arguments for both homo- and heterogeneity. From an economic perspective a heterogeneous employer branding creates a cost advantage, because with an attractive unique reputation a company can pay lower salaries than competitors for a given position. On the other hand a homogeneous branding generates cost advantages when the company benchmarks competitors or respects the institutional norms. From a social perspective a heterogeneous branding contributes to a distinct corporate identity, while a homogenous branding avoids social isolation. Consequently, homogeneity provides advantages that heterogeneity does not and vice versa. Companies therefore level the arguments. The balance is more likely to lean towards homogeneity when 1) the companies belongs to the same corporate population in one or many of the homogenizing dimensions and 2) a branding component relatively easily can be benchmarked or is connected with explicit and strong institutional norms. The balancing act signifies that a homogeneous branding is not a product of institutional determinism, but that the corporate populations give rise to different social identities and that the companies according to a logic of appropriateness act in a way that is rational given their specific situation and context. Thus, this logic creates coherent cohorts.

Abstract The school market was established in Sweden in the conjunction of several reforms, which, among other objectives, aimed at increasing diversity in the market. This allowed profitseeking firms to compete against each other in a former monopoly. According to certain theories, the mechanisms of competition are bound to make organizations more homogenous. Other researchers have claimed that differentiating mechanisms such as various strategies allow companies to become more diverse. This paradox presents an interesting research area which we have pursued. Our thesis addresses this contradiction by answering the research question: How do mechanisms of competition influence organizational diversity among charter school groups? This explanatory qualitative case study analyzes ongoing organizational trends among three Swedish charter school groups through a within – and cross case analysis. Our main findings indicate that 1) the mechanisms of competition reduces the diversity among organizations of charter school groups and thus the organizations are becoming more homogenous. However, 2) external imitation does not contribute to the homogenizing effects on organizations since brand strategy, lack of resources and transparency as well as employee resistance limits competitive imitation.

The test of homogeneity for intraclass correlation coefficients has been one of the active topics in statistical research. Several chi-square tests have been proposed to test the homogeneity of intraclass correlations in the past few decades. The big concern for them is that these methods are seriously biased when sample sizes are not large. In this thesis, data driven approaches are proposed to testing the homogeneity of intraclass correlation coefficients of several populations. Through simulation study, data driven methods have been proved to be less biased and accurate than some commonly used chi-square tests.

Forest management contributes to the changes in forest structure by turning heterogenous forests of varied age into homogenous forests of similar age and thus affect bird species depending on different structures or habitats which are lost during forestry. In this report, a study was made to investigate how the amount of decidious trees, dead wood and variation in tree diameter affect bird diversity. The purpose of this study was to be able to give forest management guidelines to increase bird diversity. This study was conducted by investigating 65 transects in forests of different structure south of Linköping, Sweden. Along the 65 transects, birds were inventoried as well as the vegetation. The trees were measured in 5 circles along each transect. The data from the investigations both on birds and vegetation were analysed by using generalized linear models. The results showed that amount of deadwood and variation in tree diameter had the strongest effects on bird diversity, and to some extent the amount of decidious trees. By applying this knowledge of the positivt effects on birds when increasning the amount of deadwood, decidious trees and variation in tree diameter in the forests, it is possible to create better conditions for maintaining species richness and diversity.

Abstract The interpretation and identification of information from the side-scan sonar imagery are mainly depended on visual observation and personal experiences. Recent studies tended to increase the identification efficiency by using numerical analysis methods. This can reduce the error that cause by the differences of observer¡¦s experience as well as by extended time observation. The position around the center line of the slant range corrected side-scan sonar imagery might result in the degradation of the ability of numerical methods to successfully detect artificial objects. Theoretically, this problem could be solved by using a specific characteristic function to identify the existence of concrete reefs, and then filtering the noise of the central line area with a threshold value. This study was intended to develop fully automatic sonar imagery processing system for the identification of cubic concrete and cross-type protective artificial reefs in Taiwan offshore area. The procedures of the automatic sonar imagery processing system are as follows: (1) Image Acquisition¡G500kHz with slant range of 75m. (2) Feature Extraction¡Ggrey level co-occurrence matrix (i.e., Entropy, Homogeneity and Mean) (3) Classification¡Gunsupervised Bayesian classifier. (4) Object Identification¡Gby characteristic feature (i.e., Entropy). (5) Object¡¦s Status Analysis¡Gobject¡¦s circumference¡Barea¡Bcenter of mass and quantity. This study used the sonar images collected at Chey-Ding artificial reef site in Kaohsiung City as a case study, aiming to verify the automatic sonar imagery processing system and find out the optimum window size. The image characteristic functions include one set of first order parameter (i.e., mean) and two sets of second order parameter (i.e., entropy and homogeneity). Eight(8) sonar images with 1-8 sets of cubic concrete and cross-type protective artificial reefs where used in this step. The identification efficiency of the system, in terms of the produce¡¦s accuracy, is 79.41%. The results illustrated that there were 16~28 sets of artificial reefs being detected in this case which is comparable with the actual amount of 17 sets. Based on this investigation, the optimum window size was concluded to be 12¡Ñ12 pixels with sliding size of 4 pixel. Imagery collected at Fang-Liau artificial reef site of Pingtung County was tested. For the purpose of applicability, the original imagery (2048¡Ñ2800 pixels) was divided into 8 consecutive smaller sized imagery frames(2048¡Ñ350 pixels). The influence of using a two-fold classification procedure and a central filtering method to reduce the noise that caused by slant range correction were discussed. The results showed that central line filtering method is applicable. The results of object¡¦s status analysis showed that there are 156-236 sets of reefs existed. Automatic determination of the target using the characteristic function of entropy is feasible. If the value is larger than 1.45, it represents positive identification of concrete artificial reefs. It can be classified as muddy sand seabed type if the value is smaller than 1.35. If the value is between 1.35~1.45, it illustrates the existence of a transition zone where objects of smaller in dimensions might exist. To achieve the purpose of automatic operation, firstly, we have to identify the existence of the concrete reefs by using the specific characteristic function. Based on the result of existing concrete reefs, suture line filtering method will hence be used to filter the noise from the image information. For that all of the procedures are automatically operated without human intervention. Key word: side-scan sonar ; characteristic function ; gray level co-occurrence matrix ; Bayesian classification ;entropy ; homogeneity ; mean

The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the imaging frequency, as determined by the static magnetic (B0) field strength. These coils are excited by one or more voltage sources. The distribution of currents on the coil elements or rungs is determined by the symmetry of the coil structure. At field strengths of 3T and above, electric properties such as the dielectric constant and conductivity of the load lead to B1 field inhomogeneity due to wavelength effects and perturbation of the coil current distribution from the ideal. The B1 field homogeneity under such conditions may be optimized by adjusting the amplitudes and phases of the currents on the rungs. However, such adjustments require independent control of current amplitudes and phases on each rung of the resonant coil. Due to both the strong coupling among the rungs of a resonant coil and the sensitivity to loading, such independent control would not be possible and B1 homogeneity optimization would involve a time consuming and impractical iterative procedure in the absence of exact knowledge of interactions among coil elements and between the coil and load. This dissertation is based on the work done towards the design and development of a RF current source that drives high amplitude RF current through an integrated array element. The arrangement is referred to as a current element. Independent control of current amplitude and phase on the current elements is demonstrated. A non-resonant coil structure consisting of current elements is implemented and B1 field pattern control is demonstrated. It is therefore demonstrated that this technology would enable effective B1 field optimization in the presence of lossy dielectric loads at high field strengths.