Finding subgroups within social networks is important for understanding and possibly influencing the formation and evolution of online communities. This thesis addresses the problem of finding cohesive subgroups within social networks inferred from online interactions. The dissertation begins with a review of relevant literature and identifies existing methods for finding cohesive subgroups. This is followed by the introduction of the SCAN method for identifying subgroups in online interaction. The SCAN (Social Cohesion Analysis of Networks) methodology involves three steps: selecting the possible members (Select), collecting those members into possible subgroups (Collect) and choosing the cohesive subgroups over time (Choose). Social network analysis, clustering and partitioning, and similarity measurement are then used to implement each of the steps. Two further case studies are presented, one involving the TorCamp Google group and the other involving YouTube vaccination videos, to demonstrate how the methodology works in practice. Behavioural measures of Sense of Community and the Social Network Questionnaire are correlated with the SCAN method to demonstrate that the SCAN approach can find meaningful subgroups. Additional empirical findings are reported. Betweenness centrality appears to be a useful filter for screening potential subgroup members, and members of cohesive subgroups have stronger community membership and influence than others. Subgroups identified using weighted average hierarchical clustering are consistent with the subgroups identified using the more computationally expensive k-plex analysis. The value of similarity measurement in assessing subgroup cohesion over time is demonstrated, and possible problems with the use of Q modularity to identify cohesive subgroups are noted. Applications of this research to marketing, expertise location, and information search are also discussed.

Finding subgroups within social networks is important for understanding and possibly influencing the formation and evolution of online communities. This thesis addresses the problem of finding cohesive subgroups within social networks inferred from online interactions. The dissertation begins with a review of relevant literature and identifies existing methods for finding cohesive subgroups. This is followed by the introduction of the SCAN method for identifying subgroups in online interaction. The SCAN (Social Cohesion Analysis of Networks) methodology involves three steps: selecting the possible members (Select), collecting those members into possible subgroups (Collect) and choosing the cohesive subgroups over time (Choose). Social network analysis, clustering and partitioning, and similarity measurement are then used to implement each of the steps. Two further case studies are presented, one involving the TorCamp Google group and the other involving YouTube vaccination videos, to demonstrate how the methodology works in practice. Behavioural measures of Sense of Community and the Social Network Questionnaire are correlated with the SCAN method to demonstrate that the SCAN approach can find meaningful subgroups. Additional empirical findings are reported. Betweenness centrality appears to be a useful filter for screening potential subgroup members, and members of cohesive subgroups have stronger community membership and influence than others. Subgroups identified using weighted average hierarchical clustering are consistent with the subgroups identified using the more computationally expensive k-plex analysis. The value of similarity measurement in assessing subgroup cohesion over time is demonstrated, and possible problems with the use of Q modularity to identify cohesive subgroups are noted. Applications of this research to marketing, expertise location, and information search are also discussed.

For a oriented genus g surface with one boundary component, S_g, the Torelli group is the group of orientation preserving homeomorphisms of S_g that induce the identity on homology. The Magnus representation of the Torelli group represents the action on F/F'' where F=π_1(S_g) and F'' is the second term of the derived series. I show that the kernel of the Magnus representation, Mag(S_g), is highly non-trivial and has a rich structure as a group. Specifically, I define an infinite filtration of Mag(S_g) by subgroups, called the higher order Magnus subgroups, M_k(S_g). I develop methods for generating nontrivial mapping classes in M_k(S_g) for all k and g≥2. I show that for each k the quotient M_k(S_g)/M_{k+1}(S_g) contains a subgroup isomorphic to a lower central series quotient of free groups E(g-1)_k/E(g-1)_{k+1}. Finally I show that for g≥3 the quotient M_k(S_g)/M_{k+1}(S_g) surjects onto an infinite rank torsion free abelian group. To do this, I define a Johnson-type homomorphism on each higher order Magnus subgroup quotient and show it has a highly non-trivial image.

Vårt syfte med denna studie är att undersöka organisationskulturen på Getinge Sterilization AB för att se om det förekommer skillnader i grundläggande antaganden för arbetarna, tjänstemännen och ledningen d.v.s. om det skiljer sig åt avseende deras uppfattning om sin vardagsverklighet, vilka dessa skillnader är och varför de uppstår. Vi vill även förstå hur dessa skillnader kan påverka organisationers möjlighet till framgång. Vi har tillämpat en kvalitativ ansats i syfte att nå en djupare förståelse för hur informanterna uppfattar organisationskulturen på fallföretaget. För att nå en sådan förståelse har vi sammanlagt gjort 12 semistrukturerade intervjuer med elva olika personer samt tre observationer. Vi har även granskat olika interna och externa dokument. Vi har valt ett abduktivt förhållningssätt i vår undersökningsprocess. Genom hela forskningsprocessen har vi använt en kartläggningsmodell (Scheins trefaktormodell) och vid analysstadiet har denna använts som ett verktyg för att bearbeta den insamlade datan. Vi har funnit att arbetarnivån uppvisar några unika drag i organisationskulturen som till viss del delas av tjänstemannanivån medan ledningen uppvisar en relativt ordinär ledningskultur. Detta innebär att det finns tydliga skillnader i grundläggande antaganden mellan de olika nivåerna i företaget. De tydligaste skillnaderna finns mellan arbetarnivån och ledningsnivån med tjänstemannanivån ofta någonstans emellan. Skillnaderna beror troligtvis på att arbetarna, tjänstemännen och ledningen har olika vardagsverkligheter att förhålla sig till. Dessa skillnader kan medföra problem i framtida förändringsarbete när företaget behöver anpassa rådande organisationskultur till mer moderna omständigheter. Organisationskultur, vardagsverklighet, grundläggande antaganden, subgrupper, kvalitativ. / The aim of this study is to examine the organizational culture at Getinge Sterilization AB to see if there were differences in the basic assumptions for the workers, the clerical staff and the management, that is; Is there a difference regarding their everyday reality? What are these differences and why do they occur? We also want to understand how these differences affect the company’s ability to succeed. We have applied a qualitative approach in order to reach a deeper understanding of how respondents perceive the organizational culture at Getinge Sterilization AB. To reach such an understanding, we have made a total of 12 semistructured interviews with eleven different people. We have also conducted three observations. Finally we studied various internal and external documents. We have chosen an abductive approach in our research process. Throughout the research process, we used a mapping model (Schein’s three factor-model) and at the analysis stage has this been used as a tool to process the gathered data. Our findings shows that the working level exhibits some unique features in the organizational culture, which to some extent is shared by the clerical staff-level while the management show a relatively ordinary management culture. This concludes that there are clear differences in the basic assumptions between the different levels in the organization. The most obvious differences exists between the working level and the management level with the clerical staff-level somewhere in between. The differences likely occur because workers, clerical staff and management relate to different everyday realities. This differences can cause problems in future organizational change processes when the company needs to adapt the existing organizational culture to more modern circumstances. Organizational culture, everyday reality, basic assumptions, subgroups, qualitative.

The theory of local newforms has been studied for the group of \(PGL_n\) and recently \(PGSp_4\) and some other groups of small ranks. In this dissertation, we develop a newform theory for generic supercuspidal representations of \(SO_{2n+1}\) over non-Archimedean local fields with odd characteristic by defining a family of open compact subgroup \(K(p^m)\), \(m \geq 0\) (up to conjugacy) which are analogous to the groups \(\Gamma(p^m)\) in the classical theory of modular forms. We give lower bounds on the dimension of the fixed subspaces of \(K(p^m)\) in terms of the conductor of the generic representation, and give a conjectural description of the space of old forms. These results generalize the known cases for n = 1,2 by Casselman [4] and Roberts and Schmidt [23]. / Mathematics

The character table of any finite group provides a considerable amount of information about a group and the use of character tables is of great importance in Mathematics and Physical Sciences. Most of the maximal subgroups of finite simple groups and their automorphisms are extensions of elementary abelian groups. Various techniques have been used to compute character tables, however Bernd Fischer came up with the most powerful and informative technique of calculating character tables of group extensions. This method is known as the Fischer-Clifford Theory and uses Fischer-Clifford matrices, as one of the tools, to compute character tables. This is derived from the Clifford theory. Here G is an extension of a group N by a finite group G, that is G = N.G. We then construct a non-singular matrix for each conjugacy class of G/N =G. These matrices, together with partial character tables of certain subgroups of G, known as the inertia groups, are used to compute the full character table of G. In this dissertation, we discuss Fischer-Clifford theory and apply it to both split and non-split extensions. We first, under the guidance of Dr Mpono, studied the group 27:S8 as a maximal subgroup of 27:SP(6,2), to familiarize ourselves to Fischer-Clifford theory. We then looked at 26:A8 and 28:O+8 (2) as maximal subgroups of 28:O+8 (2) and O+10(2) respectively and these were both split extensions. Split extensions have also been discussed quite extensively, for various groups, by different researchers in the past. We then turned our attention to non-split extensions. We started with 24.S6 and 25.S6 which were maximal subgroups of HS and HS:2 respectively. Except for some negative signs in the first column of the Fischer-Clifford matrices we used the Fisher-Clifford theory as it is. The Fischer-Clifford theory, is also applied to 53.L(3, 5), which is a maximal subgroup of the Lyon's group Ly. To be able to use the Fisher-Clifford theory we had to consider projective representations and characters of inertia factor groups. This is not a simple method and quite some smart computations were needed but we were able to determine the character table of 53.L(3,5). All character tables computed in this dissertation will be sent to GAP for incorporation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Type Ia supernovae (SNe Ia) are currently the best probe of the expansion history of the universe. Their usefulness is due chiefly to their uniformity between supernovae (SNe). However, there are some slight variations amongst SNe that have yet to be understood and accounted for. The goal of this work is to uncover relationships between the spectral features and the light curve decline rate, [delta]m₁₅. Wavelet decomposition has been used to develop a new spectral index to measure spectral line strengths independent of the continuum and easily corrected for noise. This new method yields consistent results without the arbitrary uncertainties introduced by current methods and is particularly useful for spectra which do not have a clearly defined continuum. These techniques are applied to SN Ia spectra and correlations are found between the spectral features and light curve decline rate. The wavelet spectral indexes are used to measure the evolution of spectral features which are characterized by 3 or 4 parameters for the most complicated evolution. The three absorption features studied here are associated with sulfur and silicon and all show a transition in strength between 1 to 2 weeks after B-band maximum. Pearson correlation coefficients between spectral features and [delta]m₁₅ are found to be significant within a week of maximum brightness and 3 to 4 weeks post-maximum. These correlations are used to determine the principal components at each epoch among the set of SN spectra in this work. The variation contained in the first principal component (PC1) is found to be greater than 60% to 70% for most epochs and reaching as high as 80% to 90% for epochs with the highest correlations. The same first principal component can be used to relate spectral feature strengths to the decline rate. These relations were used to estimate a SN light curve decline rate from a set of spectra taken over the course of the explosion, from a single spectrum, or from even a single spectral feature. These relationships could be used for future surveys to estimate spectral characteristics from light curve data, such as photometric redshift.

Självskadebeteende är en komplicerad företeelse som förekommer vanligast under tonårstiden. Tidigare litteratur har kunnat se en koppling mellan självskada och identifikation med vissa subgrupper såsom goth, punk och hårdrockare. Dessa personer självskadar i högre utsträckning än personer som anser sig själva tillhöra någon annan subgrupp. För att utöka kunskapen om denna länk mellan självskada och identifikation med alternativa subgrupper var studiens syfte att undersöka om identifiering med alternativa subgrupper hade samband med självskada utöver den väldokumenterade effekten av depression. Studien byggde på befintliga longitudinella data från en forskningsmiljö vid Örebro Universitet där 1478 högstadieelever följdes över ett års tid. Resultatet visade att det fanns tydliga effekter av identifikation med subgrupper tillsammans med och utöver depressiva symtom vad gäller prediktion av självskada. Kön visade sig vid kontroll av studiens övriga variabler inte påverka resultatet. Studien kom fram till att ungdomar som visar högre nivåer av både identifikation med subgrupper och depressiva symtom visar högre nivåer av självskada än någon av företeelserna separat. / Self-harming is a complicated phenomenon that is most common during adolescence. Previous literature has seen a connection between self-harm and specific subcultures such as goth, punk and hardrock that shows that members in these groups self-harm in greater extent than persons that consider themselves members of other subgroups. This study therefore aims to broaden the field of knowledge regarding this increasing problem behavior. In order to do that we examined if identifying with alternative subcultures could show a connection with self-harm, above and beyond that of the far well-documented predictor, depressive symptoms. The study was based on previous data collection that involved 1478 junior high school students that were measured over a time period of one year. The results showed that there were important effects of subculture identification not only above and beyond that of depression but also in interaction regarding influencing and predicting self-harm. Controlling for gender differences showed that it did not affect the outcome in self-harm. The study showed that adolescents that display higher levels of subculture identification and depressive symptoms show higher levels of self-harm then any of the phenomena separate.

The main purpose of this thesis is to describe methods of constructing computer-free proofs of existence of finite groups and give useful techniques to perform double coset enumeration of groups with symmetric presentations over their control groups.

Objective: In three kvasi-experimental single-case studies regarding patients with neck-pain who after sub-grouping using Treatment Based Classification (TBC), were placed in the subgroups centralization or mobilization, describe how and why they were placed in that particular subgroup and then to evaluate the effects on function and pain of the specific treatment proposed for that subgroup.    Method: The process of sub-grouping is described. Function and pain were measured with the Neck Disability Index (NDI) and Numeric Pain Rating Scale 0-10 (NPRS) before, during and after the treatment-period and 1 month after the treatment-period had ended.    Results: The use of TBC showed positive results with increased levels of function and decreased patient-reported neck pain in all three single-cases.    Conclusion: The TBC-system may be used for improving function and pain in patients with neck pain. More studies of the validity and reliability and randomized studies of the TBC-system are needed before it could be recommended generally for physiotherapists.