15 resultados para deterministic fractals

em Helda - Digital Repository of University of Helsinki


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A new deterministic three-dimensional neutral and charged particle transport code, MultiTrans, has been developed. In the novel approach, the adaptive tree multigrid technique is used in conjunction with simplified spherical harmonics approximation of the Boltzmann transport equation. The development of the new radiation transport code started in the framework of the Finnish boron neutron capture therapy (BNCT) project. Since the application of the MultiTrans code to BNCT dose planning problems, the testing and development of the MultiTrans code has continued in conventional radiotherapy and reactor physics applications. In this thesis, an overview of different numerical radiation transport methods is first given. Special features of the simplified spherical harmonics method and the adaptive tree multigrid technique are then reviewed. The usefulness of the new MultiTrans code has been indicated by verifying and validating the code performance for different types of neutral and charged particle transport problems, reported in separate publications.

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Pappret conceptualizes parsning med Constraint Grammar på ett nytt sätt som en process med två viktiga representationer. En representation innehåller lokala tvetydighet och den andra sammanfattar egenskaperna hos den lokala tvetydighet klasser. Båda representationer manipuleras med ren finite-state metoder, men deras samtrafik är en ad hoc -tillämpning av rationella potensserier. Den nya tolkningen av parsning systemet har flera praktiska fördelar, bland annat det inåt deterministiska sättet att beräkna, representera och räkna om alla potentiella tillämpningar av reglerna i meningen.

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Under the power of passion. The age of nervousness in Minna Canth s works This research contemplates the psychology of Minna Canth s characters through the historical image of man in late 19th century Europe. The central operative term of the study is passion , understood as a twofold philosophical concept that includes both desire and suffering. The method of this study is historical and contextual. The study interprets the passions and the psychology of Canth s characters as they were understood in their own time. The indicator of the relevant contexts is the realist and naturalist genre of Canth s works. New research on the genre of the time is also the basis of a new kind of psychological approach to Canth s works. The most important context of passion in Canth s works is the positivistic and pathological image of man at the end of the 19th century. Then, passion was widely discussed, and was perceived as a physiological phenomenon that influenced humans neurologically and caused different kinds of physiological symptoms and nervous disorders. But at the same time, passion was understood as a manifestation of human instincts and drives. The naturalistic literature of the day aimed at creating deterministic studies of human morality and psychology following Émile Zola s application of experimental science methods in his writing. The pathological image of man is most explicitly manifested in Canth s formerly unknown short story Lääkäri (Doctor, 1891), in which a doctor who is interested in psychology visits a jail to meet a peculiar criminal, a girl who feels no remorse for her multiple crimes. In other works of Canth the medically motivated viewpoint is more hidden in the deterministic narrative and depiction of the characters. The present study approaches the passion in Minna Canth s works through five thematic chapters, in witch characters are interpreted suffering from blind love, ennui, crippling romantic idealism, melancholy, guilt and nostalgia, and their stories can be prescribed as medical histories which depict the born of the passion and its development towards ruin. All protagonists are also manifestations of their own time. Canth criticises the modern life and its demands as well as social defects through the tragic stories of individuals. The study demonstrates that Canth did not, like previous research has suggested, wait until the 1890s before writing works of a psychological nature but had already written according to the psychological paradigm of her time in Työmiehen vaimo (1885). The social and psychological interests intertwine in Canth s works and are not exclusionary as has formerly been interpreted. Canth is also critical of the medical power implicit in the naturalist experimental method and this shows itself especially in her depiction of working class women.

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Education for a Technological Society. Public School Curriculum Construction, 1945-1952. The subject of my research is the significance of technology in the construction process of the public school curriculum during the years 1945-1952. During the period the war reparation and rebuilding placed demands and actions to rationalise and dramatise industry and agriculture. Thereby the ambitions of building a technological country and the reformation of curriculum took place simultaneously. Fordistian terms of reference, of which the principles were mass production, rationalisation and standardisation, a hierarchical division of labour and partition of assignments, provided a model for the developing curriculum. In the research the curriculum is examined as an artefact, which shapes socio-technically under the influence of social and technical factors. In the perspective of socio-technical construction the artefact is represented by the viewpoints of members of relevant social groups. The groups give meaning to the curriculum artefact, which determines the components of the curriculum. The weakness of the curriculum was its ineffectiveness, which was due to three critical problems. Firstly, the curriculum was to be based on scientific work, which meant the development of schools through experiments and scientific research. Secondly, the civilised conseption in the curriculum was to be composed of theoretical knowledge, as well as practical skills. Practical education was useful for both the individual and society. Thirdly, the curriculum was to be reformed in a way that the individuality of the pupil would be taken into account. It was useful for the society that talents and natural abilities of every pupil were observed and used to direct the pupil to the proper place in the social division of labour, according to the "right man in a right place" principle. The solutions to critical problems formed the instructions of the public school curriculum, which described the nature and content of education. Technology and its development were on essential part of the whole school curriculum process. The quality words connected to the development of technology - progress, rationality and effectiveness - were also suitable qualifiers and reasons for the reform of the curriculum. On the other hand, technology set a point of comparison and demand for the development of all phases of education. The view of technology was not clearly deterministic - it was also possible to shape technological society with the help of education. The public school curriculum process indicates how originally the principles of technological systems were shaped to the language of education and accepted in educational content.

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The goal of this research was to survey the self-concept and school achievement of pupils with cleft lip, cleft palate or both from juvenile age to adolescence. Longitudinal researches of self-concept and school achievement among pupils with cleft lip, cleft palate or both are uncommon. This research was the first longitudinal research ever conducted in Finland among this population. This research can be considered to be a special educational study because of the target group involved. Self-concept consists of the person s entire personality. Personality is biological and deterministic. Self-concept includes concepts, attitudes and feelings that the person has about him or her qualities, abilities and relations to the environment. The individual associates experiences to this personality with earlier observations through the social interaction. The individual will have the consciousness of the person s existence and action. The target group in this study consisted of Finnish children with clefts, who were comprised of four different age groups. The questionnaire was sent to all subjects (N1 = 419) both times. A total of 74 % of children returned the questionnaire in 1988 (N2=305). 48 % of children returned the questionnaire in 1993 (N3=203). 42% of children returned the questionnaire both times (N4=175) . These 175 children formed the research subjects. The survey was conducted in 1988, and again in 1993. In 1988, the pupils surveyed were 9 to 12 years of age, while in 1993 they were between 14 and 17 years old. The data was collected through the use of a questionnaire, which consisted of common questions and a personality inventory test that was developed for Finnish students by professor Maija-Liisa Rauste-von Wright. Quantitative analysis methods were used to examine the structure of self-concept and school achievement. Structures found in this research were observed in relation to disorder, gender and maturation. According to these results, structures of self-concepts and school achievement are in fact stable. Basic self-concept elements are seen to be formed at an early age. The developmental aspects of self-concept following puberty are observed as the stability of self-concept and as the forming of a general self. The level of school achievement is stable, but the structure of school achievement changes. From these results, it is possible to state that the gender of the child has a statistical significance regarding self-concept and school achievement. However, the experienced disorder does not have statistical significance as regards to self-concept and school achievement. Results of self-concept support the research of self-concept conducted earlier in Finland.

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The Russian mathematician, academician and former dissident Igor Shafarevich (b. 1923) is commonly mentioned in Western scholarly studies on perestroika and post-perestroika-era Russian politics as one of the most notable anti-Semites and extreme nationalists of the country. This notoriety owes to Shafarevich’s old samizdat article Russophobia, which was published in 1988. The scandal surrounding Russophobia came to a head when the president of The National Academy of Sciences in the United States asked Shafarevich, its honorary member, to resign. Nothing like this had ever happened in the academy’s history. The present dissertation discusses Shafarevich’s political activities, his texts and ideas as well as their reception. Particular attention is given to Russophobia, whose detailed examination proves very clearly that its reputation as an anti-Semitic text is groundless. The reasons for Russophobia’s hasty but fierce condemnation were many, but only one was that when the Soviet system began to tumble, it was commonly assumed that a vigorous rise in anti-Semitism and extreme nationalism in the Soviet Union/Russia would be just a matter of time. Many observers were highly sensitised to detecting its signs and symptoms. The dissertation also shows that most of those to write the first criticisms of Russophobia and to liken Shafarevich to the ideologues of Nazi Germany were the same people he had criticised in Russophobia for their deterministic view of history and irrational manner of connecting things for the purpose of fanning the flames of distrust between Russia’s Jews and Russians. In retrospect, it is fairly evident that Shafarevich actually managed to effectively “neutralise” the message of many of those obsessed with the Jews among his Russian contemporaries and contributed to the fact that anti-Jewish sentiments have been a great deal less popular in post-communist Russia than so many had feared and expected. The thesis also thoroughly discusses Shafarevich’s other texts and activities before Russophobia’s appearance and after it. In the 1970s, Shafarevich was one of the best-known dissidents in the Soviet Union. He worked together with academician Andrei Sakharov in a dissidents’ unofficial human rights committee and co-operated closely with Aleksandr Solzhenitsyn before Solzhenitsyn’s exile. Then, during the chaotic years of perestroika, Shafarevich defended the basic rights of ordinary citizens and warned that the hype concerning democracy could become counterproductive if the most palpable result of the reforms was the disappearance of citizens’ basic security and elementary social justice. One of the conclusions of the thesis is that even if the world around Shafarevich has changed considerably, his views have remained essentially the same since the late 1960s and early 1970s.

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Genetic studies on phylogeography and adaptive divergence in Northern Hemisphere fish species such as three-spined stickleback (Gasterosteus aculeatus) provide an excellent opportunity to investigate genetic mechanisms underlying population differentiation. According to the theory, the process of population differentiation results from a complex interplay between random and deterministic processes as well historical factors. The main scope in this thesis was to study how historical factors like the Pleistocene ice ages have shaped the patterns molecular diversity in three-spined stickleback populations in Europe and how this information could be utilized in the conservation genetic context. Furthermore, identifying footprints of natural selection at the DNA level might be used in identifying genes involved in evolutionary change. Overall, the results from phylogeographic studies indicate that the three-spined stickleback has colonized the Atlantic basin relatively recently but constitutes three major evolutionary lineages in Europe. In addition, the colonization of freshwater appears to result from multiple and independent invasions by the marine conspecifics. Molecular data together with morphology suggest that the most divergent freshwater populations are located in the Balkan Peninsula and these populations deserve a special conservation genetic status without warranting further taxonomical classification. In order to investigate the adaptive divergence in Fennoscandian three-spined stickleback populations several approaches were used. First, sequence variability in the Eda-gene, coding for the number of lateral plates, was concordant with the previously observed global pattern. Full plated allele is in high frequencies among marine populations whereas low plated allele dominates in the freshwater populations. Second, a microsatellite based genome scan identified both indications of balancing and directional selection in the three-spined stickleback genome, i.e. loci with unusually similar or unusually different allele frequencies over populations. The directionally selected loci were mainly associated with the adaptation to freshwater. A follow up study conducting a more detailed analysis in a chromosome region containing a putatively selected gene locus identified a fairly large genomic region affected by natural selection. However, this region contained several gene predictions, all of which might be the actual target of natural selection. All in all, the phylogeographic and adaptive divergence studies indicate that most of the genetic divergence has occurred in the freshwater populations whereas the marine populations have remained relatively uniform.

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This study investigates primary and secondary school teachers’ social representations and ways to conceptualise new technologies. The focus is both on teachers’ descriptions, interpretations and conceptions of technology and on the adoption and formation of these conceptions. In addition, the purpose of this study is to analyse how the national objectives of the information society and the implementation of information and communication technologies (ICT) in schools reflect teachers’ thinking and everyday practices. The starting point for the study is the idea of a dynamic and mutual relationship between teachers and technology so that technology does not affect one-sidedly teachers’ thinking. This relationship is described in this study as the teachers’ technology relationship. This concept emphasises that technology cannot be separated from society, social relations and the context where it is used but it is intertwined with societal practices and is therefore formed in interaction with the material and social factors. The theoretical part of this study encompasses three different research traditions: 1) the social shaping of technology, 2) research on how schools and teachers use technology and 3) social representations theory. The study was part of the Helmi Project (Holistic development of e-Learning and business models) in 2001–2005 at the Helsinki University of Technology, SimLab research unit. The Helmi Project focused on different aspects of the utilisation of ICT in teaching. The research data consisted of interviews of teachers and principals. Altogether 37 interviews were conducted in 2003 and 2004 in six different primary and secondary schools in Espoo, Finland. The data was analysed applying grounded theory. The results showed that the teachers’ technology relationship was diverse and context specific. Technology was interpreted differently depending on the context: the teachers’ technology related descriptions and metaphors illustrated on one hand the benefits and the possibilities and on the other hand the problems and threats of different technologies. The dualist nature of technology was also expressed in the teachers’ thinking about technology as a deterministic and irrevocable force and as a controllable and functional tool at the same time. Teachers did not consider technology as having a stable character but they interpreted technology in relation to the variable context of use. This way they positioned or anchored technology into their everyday practices. The study also analysed the formation of the teachers’ technology relationship and the ways teachers familiarise themselves with new technologies. Comparison of different technologies as well as technology related metaphors turned out to be significant in forming the technology relationship. Also the ways teachers described the familiarisation process and the interpretations of their own technical skills affected the formation of technology relationship. In addition, teachers defined technology together with other teachers, and the discussions reflected teachers’ interpretations and descriptions.

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A better understanding of stock price changes is important in guiding many economic activities. Since prices often do not change without good reasons, searching for related explanatory variables has involved many enthusiasts. This book seeks answers from prices per se by relating price changes to their conditional moments. This is based on the belief that prices are the products of a complex psychological and economic process and their conditional moments derive ultimately from these psychological and economic shocks. Utilizing information about conditional moments hence makes it an attractive alternative to using other selective financial variables in explaining price changes. The first paper examines the relation between the conditional mean and the conditional variance using information about moments in three types of conditional distributions; it finds that the significance of the estimated mean and variance ratio can be affected by the assumed distributions and the time variations in skewness. The second paper decomposes the conditional industry volatility into a concurrent market component and an industry specific component; it finds that market volatility is on average responsible for a rather small share of total industry volatility — 6 to 9 percent in UK and 2 to 3 percent in Germany. The third paper looks at the heteroskedasticity in stock returns through an ARCH process supplemented with a set of conditioning information variables; it finds that the heteroskedasticity in stock returns allows for several forms of heteroskedasticity that include deterministic changes in variances due to seasonal factors, random adjustments in variances due to market and macro factors, and ARCH processes with past information. The fourth paper examines the role of higher moments — especially skewness and kurtosis — in determining the expected returns; it finds that total skewness and total kurtosis are more relevant non-beta risk measures and that they are costly to be diversified due either to the possible eliminations of their desirable parts or to the unsustainability of diversification strategies based on them.

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This paper examines the relationships between uncertainty and the perceived usefulness of traditional annual budgets versus flexible budgets in 95 Swedish companies. We form hypotheses that the perceived usefulness of the annual budgets as well as the attitudes to more flexible budget alternatives are influenced by the uncertainty that the companies face. Our study distinguishes between two separate kinds of uncertainty: exogenous stochastic uncertainty (deriving from the firm’s environment) and endogenous deterministic uncertainty (caused by the strategic choices made by the firm itself). Based on a structural equations modelling analysis of data from a mail survey we found that the more accentuated exogenous uncertainty a company faces, the more accentuated is the expected trend towards flexibility in the budget system, and vice versa; the more endogenous uncertainty they face, the more negative are their attitudes towards budget flexibility. We also found that these relationships were not present with regard to the attitudes towards the usefulness of the annual budget. Noteworthy is, however, that there was a significant negative relationship between the perceived usefulness of the annual budget and budget flexibility. Thus, our results seem to indicate that the degree of flexibility in the budget system is influenced by both general attitudes towards the usefulness of traditional budgets and by the actual degree of exogenous uncertainty a company faces and by the strategy that it executes.

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An edge dominating set for a graph G is a set D of edges such that each edge of G is in D or adjacent to at least one edge in D. This work studies deterministic distributed approximation algorithms for finding minimum-size edge dominating sets. The focus is on anonymous port-numbered networks: there are no unique identifiers, but a node of degree d can refer to its neighbours by integers 1, 2, ..., d. The present work shows that in the port-numbering model, edge dominating sets can be approximated as follows: in d-regular graphs, to within 4 − 6/(d + 1) for an odd d and to within 4 − 2/d for an even d; and in graphs with maximum degree Δ, to within 4 − 2/(Δ − 1) for an odd Δ and to within 4 − 2/Δ for an even Δ. These approximation ratios are tight for all values of d and Δ: there are matching lower bounds.

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We present a distributed algorithm that finds a maximal edge packing in O(Δ + log* W) synchronous communication rounds in a weighted graph, independent of the number of nodes in the network; here Δ is the maximum degree of the graph and W is the maximum weight. As a direct application, we have a distributed 2-approximation algorithm for minimum-weight vertex cover, with the same running time. We also show how to find an f-approximation of minimum-weight set cover in O(f2k2 + fk log* W) rounds; here k is the maximum size of a subset in the set cover instance, f is the maximum frequency of an element, and W is the maximum weight of a subset. The algorithms are deterministic, and they can be applied in anonymous networks.

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We present a distributed 2-approximation algorithm for the minimum vertex cover problem. The algorithm is deterministic, and it runs in (Δ + 1)2 synchronous communication rounds, where Δ is the maximum degree of the graph. For Δ = 3, we give a 2-approximation algorithm also for the weighted version of the problem.

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We present a local algorithm (constant-time distributed algorithm) for finding a 3-approximate vertex cover in bounded-degree graphs. The algorithm is deterministic, and no auxiliary information besides port numbering is required. (c) 2009 Elsevier B.V. All rights reserved.

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We present a distributed 2-approximation algorithm for the minimum vertex cover problem. The algorithm is deterministic, and it runs in (Δ + 1)2 synchronous communication rounds, where Δ is the maximum degree of the graph. For Δ = 3, we give a 2-approximation algorithm also for the weighted version of the problem.