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Aspects of Yang-Mills Theory : Solitons, Dualities and Spin ChainsFreyhult, Lisa January 2004 (has links)
<p>One of the still big problems in the Standard Model of particle physics is the problem of confinement. Quarks or other coloured particles have never been observed in isolation. Quarks are only observed in colour neutral bound states. The strong interactions are described using a Yang-Mills theory. These type of theories exhibits asymptotic freedom, i.e. the coupling is weak at high energies. This means that the theory is perturbative at high energies only. Understanding quark confinement requires knowledge of the non perturbative regime. One attempt has been to identify the proper order parameters for describing the low energy limit and then to write down effective actions in terms of these order parameters. We discuss one possible scenario for confinement and the effective models constructed with this as inspiration. Further we discuss solitons in these models and their properties.</p><p>Yang-Mills theory has also become important in the context of string theory. According to the AdS/CFT correspondence string theory in AdS<sub>5</sub>×S<sup>5</sup> is dual to four dimensional Yang-Mills with four supersymmetries. The duality relate the non perturbative regime of one of the theories to the perturbative regime of the other. This makes it in general hard to test this conjecture. For a special type of solutions it is however possible to use a perturbative expansion in both theories. We discuss this type of solutions and in particular we discuss a method, the Bethe ansatz, to find the solutions on the gauge theory side.</p>
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Strings as Sigma Models and in the Tensionless LimitPersson, Jonas January 2007 (has links)
<p>This thesis considers two different aspects of string theory, the tensionless limit of the string and supersymmetric sigma models with extended supersymmetry. First, the tensionless limit is used to find a IIB supergravity background generated by a tensionless string. The background has the characteristics of a gravitational shock-wave. Then, the quantization of the tensionless string in a pp-wave background is performed and the result is found to agree with what is obtained by taking a tensionless limit directly in the quantized theory of the tensile string. Hence, in the pp-wave background the tensionless limit commutes with quantization. Next, supersymmetric sigma models and the relation between extended world-sheet supersymmetry and target space geometry is studied. The sigma model with N=(2,2) extended supersymmetry is considered and the requirement on the target space to have a bi-Hermitean geometry is reviewed. The Hamiltonian formulation of the model is constructed and the target space is shown to have generalized Kähler geometry. The equivalence between bi-Hermitean geometry and generalized Kähler follows, in this context, from the equivalence between the Lagrangian- and Hamiltonian formulation of the sigma model. Then, T-duality in the Hamiltonian formulation of the sigma model is studied and the explicit T-duality transformation is constructed. It is shown that the transformation is a symplectomorphism, i.e. a generalization of a canonical transformation. Under certain assumptions, the amount of extended supersymmetry present in the sigma model is shown to be preserved under the T-duality transformation. Next, extended supersymmetry in a first order formulation of the sigma model is studied. By requiring N=(2,2) extended world-sheet supersymmetry an intriguing geometrical structure arises and in a special case generalized complex geometry is found to be contained in the new framework.</p>
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Aspects of Yang-Mills Theory : Solitons, Dualities and Spin ChainsFreyhult, Lisa January 2004 (has links)
One of the still big problems in the Standard Model of particle physics is the problem of confinement. Quarks or other coloured particles have never been observed in isolation. Quarks are only observed in colour neutral bound states. The strong interactions are described using a Yang-Mills theory. These type of theories exhibits asymptotic freedom, i.e. the coupling is weak at high energies. This means that the theory is perturbative at high energies only. Understanding quark confinement requires knowledge of the non perturbative regime. One attempt has been to identify the proper order parameters for describing the low energy limit and then to write down effective actions in terms of these order parameters. We discuss one possible scenario for confinement and the effective models constructed with this as inspiration. Further we discuss solitons in these models and their properties. Yang-Mills theory has also become important in the context of string theory. According to the AdS/CFT correspondence string theory in AdS5×S5 is dual to four dimensional Yang-Mills with four supersymmetries. The duality relate the non perturbative regime of one of the theories to the perturbative regime of the other. This makes it in general hard to test this conjecture. For a special type of solutions it is however possible to use a perturbative expansion in both theories. We discuss this type of solutions and in particular we discuss a method, the Bethe ansatz, to find the solutions on the gauge theory side.
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How You Have Fallen: Exploring the Benevolence of an Early Christian God as Seen Through a Progressively Embodied SatanGeiger, Kari J 01 April 2013 (has links)
This paper attempts to explore the creation of Satan as an embodiment of evil in Early Christian theodicy. I use Greco-Roman myth and the Old Testament Book of Job to explore "duality," a system in which good and evil are encapsulated in gods or God. I attempt to trace the trajectory of a shift from this duality to a system of Christian cosmic "dualism," in which good and evil are separated as opposing forces. This shift is explored through the intertestamental Pseudepigrapha of 1 Enoch and Jubilees, towards the New Testament story of the Temptation of Christ in Matthew, Mark, and Luke. Finally, exploring post-New Testament Christian ideas with Origen's seminal work On First Principles and the martyr text of Perpetua to investigate the Early Christian community's ideas of good, God, evil, and Satan.
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Coordinated Beamforming and Common Message Decoding for Intercell Interference Mitigation in Multicell NetworksDahrouj, Hayssam 15 February 2011 (has links)
Conventional multicell wireless systems operate with out-of-cell interference treated as background noise; consequently, their performance faces two major limitations: 1)Signal processing is performed on a per-cell basis; and 2)Intercell interference detection is infeasible as intercell interference, although significantly above the noise level, is typically quite weak. In this thesis, we consider a multicell downlink scenario, where base-stations are equipped with multiple transmit antennas, the remote users are equipped with a single antenna, and multiple remote users are active simultaneously via spatial division multiplexing. We propose solutions for the above limitations by considering techniques for mitigating interference.
The first part of the thesis proposes solutions for the first limitation. It considers the benefit of coordinating base-stations across multiple cells, where
multiple base-stations may jointly optimize their respective beamformers to improve the overall system performance. It focuses on the design criteria of minimizing either the total weighted transmitted power or the maximum per-antenna power across the base-stations subject to signal-to-interference-and-noise-ratio (SINR) constraints at the remote users. The main contribution of this part is an efficient algorithm for finding the joint globally optimal beamformers across all base-stations. The proposed algorithm is based on a generalization of uplink-downlink duality to the multicell setting using the Lagrangian duality theory. An important feature is that it naturally leads to a distributed implementation in time-division duplex (TDD) systems. Simulation results suggest that coordinating the beamforming vectors alone already provides appreciable performance improvements as compared to the conventional per-cell optimized network.
The second part of the thesis considers the transmission of both private and common messages for the sole purpose of intercell
interference mitigation. It solves the issues of the second limitation mentioned above. It considers the benefit of designing
decodable interference signals by allowing common-private message splitting at the transmitter and common message decoding by users in adjacent cells. It solves a network optimization problem of jointly determining the appropriate users in adjacent cells for
rate splitting, the optimal beamforming vectors for both common and private messages, and the optimal common-private rates to minimize the total transmit power across the base-stations subject to service rate requirements for remote users. Observe that for fixed user selection and fixed common-private rate splitting, the optimization of beamforming vectors can be performed using a semidefinite programming approach. Further, this part of the thesis proposes a heuristic user-selection and rate splitting strategy to maximize the benefit of common message decoding. This part proposes a heuristic algorithm to characterize the improvement in the feasible rates with common-message decoding. Simulation results show that common message decoding can significantly improve both the total transmit power and the feasibility region for cell-edge users when base-stations are closely spaced from each other.
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Coordinated Beamforming and Common Message Decoding for Intercell Interference Mitigation in Multicell NetworksDahrouj, Hayssam 15 February 2011 (has links)
Conventional multicell wireless systems operate with out-of-cell interference treated as background noise; consequently, their performance faces two major limitations: 1)Signal processing is performed on a per-cell basis; and 2)Intercell interference detection is infeasible as intercell interference, although significantly above the noise level, is typically quite weak. In this thesis, we consider a multicell downlink scenario, where base-stations are equipped with multiple transmit antennas, the remote users are equipped with a single antenna, and multiple remote users are active simultaneously via spatial division multiplexing. We propose solutions for the above limitations by considering techniques for mitigating interference.
The first part of the thesis proposes solutions for the first limitation. It considers the benefit of coordinating base-stations across multiple cells, where
multiple base-stations may jointly optimize their respective beamformers to improve the overall system performance. It focuses on the design criteria of minimizing either the total weighted transmitted power or the maximum per-antenna power across the base-stations subject to signal-to-interference-and-noise-ratio (SINR) constraints at the remote users. The main contribution of this part is an efficient algorithm for finding the joint globally optimal beamformers across all base-stations. The proposed algorithm is based on a generalization of uplink-downlink duality to the multicell setting using the Lagrangian duality theory. An important feature is that it naturally leads to a distributed implementation in time-division duplex (TDD) systems. Simulation results suggest that coordinating the beamforming vectors alone already provides appreciable performance improvements as compared to the conventional per-cell optimized network.
The second part of the thesis considers the transmission of both private and common messages for the sole purpose of intercell
interference mitigation. It solves the issues of the second limitation mentioned above. It considers the benefit of designing
decodable interference signals by allowing common-private message splitting at the transmitter and common message decoding by users in adjacent cells. It solves a network optimization problem of jointly determining the appropriate users in adjacent cells for
rate splitting, the optimal beamforming vectors for both common and private messages, and the optimal common-private rates to minimize the total transmit power across the base-stations subject to service rate requirements for remote users. Observe that for fixed user selection and fixed common-private rate splitting, the optimization of beamforming vectors can be performed using a semidefinite programming approach. Further, this part of the thesis proposes a heuristic user-selection and rate splitting strategy to maximize the benefit of common message decoding. This part proposes a heuristic algorithm to characterize the improvement in the feasible rates with common-message decoding. Simulation results show that common message decoding can significantly improve both the total transmit power and the feasibility region for cell-edge users when base-stations are closely spaced from each other.
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Stöd eller tillrättavisning : En kvantitativ studie om socialarbetares attityder till ekonomisk rådgivning som metod / Support or lecture : A quantitative study of social workers attitudes towards economic counselingas a methodTrender, Tina, De Geer, Nina January 2012 (has links)
The aim of this bachelor thesis was to examine attitudes among social workers, particularly their attitudes toward their clients’ poverty and towards economic counseling as a method. A further aim was to study the relationship between attitudes towards poverty and economic counseling. Primary data used for the study was assembled among social workers (n = 111) with the use of an electronic questionnaire that was sent out to social welfare offices in 34 city districts in Stockholm,Gothenburg and Malmö. The findings showed that a majority of the social workers had a structural understanding of poverty and a positive attitude towards economic counseling. No correlations were found between the attitudes towards poverty and towards economic counseling. Although economic counseling can be seen as a method for individual change, the social workers had a positive attitude towards using it with clients’ whose inability to support themselves was interpreted as structurally implied. This was understood as a means to minimize the negative effects of poverty and as a way to go beyond administrative tasks. Through Giddens duality of structure theory, economic counseling was interpreted as a way of affecting the structurally caused problem of poverty by changing the actions of the client.
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Dokumentation av finansiell rådgivning : ett förbättringsprojekt inom Skandiabanken / Documentation of financial advice : an improvement projekt within SkandiabankenHagenmalm, Pia January 2011 (has links)
I ett modernt företag som Skandiabanken, vars ambition är att tillhöra de främsta inom sin bransch och som har en vision som säger att företaget ska ”ha sparmarknadens nöjdaste kunder”, ställs stora krav på effektivitet i alla led. För att möta kraven från kunder att producera varor och tjänster som motsvarar, eller helst överträffar kundernas förväntningar, samt för att möta organisationens egenintresse i att producera varor och tjänster på ett kostnadseffektivt och inkomstbringande sätt för att på så sätt säkra lönsamheten och konkurrenskraften på lång sikt, behöver företaget ständigt se över och utveckla verksamheten. D.v.s. för att överleva på en konkurrensutsatt marknad är ett strategiskt och hållbart kvalitetsarbete, och att snabbt kunna anpassa och utveckla verksamheten, av allra största vikt. Det finns inget utrymme för uppenbara kvalitetsbrister varken i verksamheten eller i produkter och tjänster som denna åstadkommer. Den snabba utvecklingen på finansmarknaderna, i kombination med att de finansiella produkter som erbjuds idag kan vara komplexa och svårbedömda, innebär att de finansiella rådgivarna under de senaste åren har fått en allt större betydelse för både privatpersoner och juridiska personer. Till grund för detta förbättringsprojekt ligger konstaterade kvalitetsbrister i den dokumentation som enligt lag ska upprättas vid all finansiell rådgivning. Syftet med förbättringsprojektet var att besvara nedan frågeställningar: Vad är de bakomliggande orsakerna till de konstaterade kvalitetsbristerna i dokumentationen av den finansiella rådgivningen? Vilka förändringar behöver genomföras för att kvaliteten ska bli bättre? Att notera här är att en bristfälligt eller utelämnad dokumentation inte per automatik behöver innebära att dåliga råd har lämnats. Metoder som använts för att utreda de bakomliggande orsakerna till kvalitetsbristerna har varit processkartläggning, orsaks-verkan-diagram, relationsdiagram, enkät, personliga intervjuer samt dokumentgranskningar. Förbättringsarbetet har, utifrån konstaterade huvudorsaker, fokuserat på förbättring av verktyg och dokument. Detta har inneburit ett tydliggörande av dokumentationspliktens innebörd vilket genererat i ett framtagande av riktlinjer samt en förbättrad dokumentationsblankett. En reflektion efter projektets avslut är att kvalitetsförbättrande punktinsatser självklart är bra men att det inte är tillräckligt. Den viktigaste slutsatsen är därmed att avsaknaden av synliggjorda ledningsprocesser, en helhetssyn på verksamheten och ett systematiskt processorienterat arbete i kombination med återkommande omorganisationer är den troliga orsaken till att de beskrivna problemen uppstått. Därför är författarens förbättringsförslag, att som ett led i Total Quality Management, starta ett arbete i enlighet med ISO 9001:2008. För att uppnå ett hållbart långsiktigt kvalitetsarbete krävs en helhetssyn och ett systematiskt och ständigt pågående förbättringsarbete. Ett arbete med 9001:2008, i enlighet med TQM och tillsammans med de faktaunderlag som de facto redan finns tillgängliga, såsom policys, riktlinjer, rutinbeskrivningar, kundundersökningar mm, kommer att generera i förbättrad effektivitet, minskad resursåtgång, förbättrad möjlighet till verksamhetsstyrning, högre kvalitet i affären, högre kundnöjdhet, nöjda medarbetare och ägare, samt att ett långsiktigt bra ekonomiskt resultat uppnås. Dessutom blir verksamheten snabbare och mer flexibel inför framtida förändringar. / In a modern company like Skandia who wants to be in the forefront of its business and with a vision to have “the most satisfied clients in the savings market” there is high demand on efficiency in all aspects of the business. To meet the demand from customers to produce products and services that meets or even better exceeds the customers’ expectations, and to meet the organization self interest in I producing products and services in a cost efficient way and with revenues to secure profitability, and competitive long term, the company at all times needs to evaluate the strategic and sustainable quality work, and that swiftly have the ability to develop the company is of extreme importance. There is no room for obvious quality deficiencies in either the product or services that the deficiency creates. The fast development in financial market in combination with the financial products that today is more complex and harder to understand the implication is that the financial advisors during the last years have a larger influence for both private persons and legal entities. The foundation for this improvement project has been to answer the questions; What are the underlying reasons for the lack of quality in the documentation of the financial advice meeting? What has to be done to improve the quality? Note that a poor or total lack of customer documentation dose not mean that bad advice has been given to the client. Methods which has been used to investigate the underlying reasons for the lack of quality has been process mapping, reason-effect diagram, relations diagram, survey, personal interviews , and examining of documents. The improvement work has, with the fact based main reasons, focused on improving the tools and documents, which have made it clearer, make people understand the reasons for the documentation regulation and the production of a new guideline and an improved document for the financial advisor. The most imported conclusion is that a lack of clear management processes, a holistic view of the business and a systematic process oriented work, in combination with a lot at reorganizations is the reason for the described problem. That is the reason for the author’s improvement suggestion, as a step in Total Quality Management, start of a work according to ISO 9001:2008. A reflection after the project was finished I that ad hoc quality improvement is of course good but not good enough. To reach a sustainable long-term quality work there is a need for a holistic view and a constant improvement focus. A work with 9001:2008 in accordance with TQM that together with fact based approach that already Is there like policy’s, guidelines, routine manuals, customer surveys among others will lead to better efficiency, less use of resources, improved opportunity lead the business, higher quality in the business, increased customer satisfaction, more pleased staff and owners, and a long term financial result will be accomplished. Further the business will be faster on more flexible for future changes.
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Dualities In Bergson Revisited: Towards A Reconciliation?Karahan, Gulizar 01 June 2008 (has links) (PDF)
The aim of this study is to make an inquiry on the nature and the development of dualities in Bergson&rsquo / s philosophy. Since the nature of each duality differs from the others and the dualistic pattern inherent in Bergsonian philosophy is subject to change, we base our study on a chronological structure in order to comprehend better how this pattern changes. We claim that such an inquiry will yield relevant outcomes with regard to ontological and epistemological evolution of Bergson&rsquo / s thought. To state more precisely, we are of the idea that the modification in the dualistic pattern in Bergson&rsquo / s ontology is reflected in a parallel manner in his epistemology. The fundamental question that shows us the way to follow in our study is whether the elements of the dualities (whether they be ontological or epistemological) are reconciled by Bergson or they are left as absolutely distinct elements. At the end of the inquiry regarding that question, which we believe can be taken as an inspiring point in developing new approaches especially to epistemological problems, our conviction is that Bergson points out to a meeting point.
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Duality for convex composed programming problemsVargyas, Emese Tünde 20 December 2004 (has links) (PDF)
The goal of this work is to present a conjugate duality treatment of composed programming as well as to give an overview of some recent developments in both scalar and multiobjective optimization.
In order to do this, first we study a single-objective optimization problem, in which the objective function as well as the constraints are given by composed functions. By means of the conjugacy approach based on the perturbation theory, we provide different kinds of dual problems to it and examine the relations between the optimal objective values of the duals. Given some additional assumptions, we verify the equality between the optimal objective values of the duals and strong duality between the primal and the dual problems, respectively. Having proved the strong duality, we derive the optimality conditions for each of these duals. As special cases of the original problem, we study the duality for the classical optimization problem with inequality constraints and the optimization problem without constraints.
The second part of this work is devoted to location analysis. Considering first the location model with monotonic gauges, it turns out that the same conjugate duality principle can be used also for solving this kind of problems. Taking in the objective function instead of the monotonic gauges several norms, investigations concerning duality for different location problems are made.
We finish our investigations with the study of composed multiobjective optimization problems. In doing like this, first we scalarize this problem and study the scalarized one by using the conjugacy approach developed before. The optimality conditions which we obtain in this case allow us to construct a multiobjective dual problem to the primal one. Additionally the weak and strong duality are proved. In conclusion, some special cases of the composed multiobjective optimization problem are considered. Once the general problem has been treated, particularizing the results, we construct a multiobjective dual for each of them and verify the weak and strong dualities. / In dieser Arbeit wird, anhand der sogenannten konjugierten Dualitätstheorie, ein allgemeines Dualitätsverfahren für die Untersuchung verschiedener Optimierungsaufgaben dargestellt. Um dieses Ziel zu erreichen wird zuerst eine allgemeine Optimierungsaufgabe betrachtet, wobei sowohl die Zielfunktion als auch die Nebenbedingungen zusammengesetzte Funktionen sind. Mit Hilfe der konjugierten Dualitätstheorie, die auf der sogenannten Störungstheorie basiert, werden für die primale Aufgabe drei verschiedene duale Aufgaben konstruiert und weiterhin die Beziehungen zwischen deren optimalen Zielfunktionswerten untersucht. Unter geeigneten Konvexitäts- und Monotonievoraussetzungen wird die Gleichheit dieser optimalen Zielfunktionswerte und zusätzlich die Existenz der starken Dualität zwischen der primalen und den entsprechenden dualen Aufgaben bewiesen. In Zusammenhang mit der starken Dualität werden Optimalitätsbedingungen hergeleitet. Die Ergebnisse werden abgerundet durch die Betrachtung zweier Spezialfälle, nämlich die klassische restringierte bzw. unrestringierte Optimierungsaufgabe, für welche sich die aus der Literatur bekannten Dualitätsergebnisse ergeben.
Der zweite Teil der Arbeit ist der Dualität bei Standortproblemen gewidmet. Dazu wird ein sehr allgemeines Standortproblem mit konvexer zusammengesetzter Zielfunktion in Form eines Gauges formuliert, für das die entsprechenden Dualitätsaussagen abgeleitet werden. Als Spezialfälle werden Optimierungsaufgaben mit monotonen Normen betrachtet. Insbesondere lassen sich Dualitätsaussagen und Optimalitätsbedingungen für das klassische Weber und Minmax Standortproblem mit Gauges als Zielfunktion herleiten.
Das letzte Kapitel verallgemeinert die Dualitätsaussagen, die im zweiten Kapitel erhalten wurden, auf multikriterielle Optimierungsprobleme. Mit Hilfe geeigneter Skalarisierungen betrachten wir zuerst ein zu der multikriteriellen Optimierungsaufgabe zugeordnetes skalares Problem. Anhand der in diesem Fall erhaltenen Optimalitätsbedingungen formulieren wir das multikriterielle Dualproblem. Weiterhin beweisen wir die schwache und, unter bestimmten Annahmen, die starke Dualität. Durch Spezialisierung der Zielfunktionen bzw. Nebenbedingungen resultieren die klassischen konvexen Mehrzielprobleme mit Ungleichungs- und Mengenrestriktionen. Als weitere Anwendungen werden vektorielle Standortprobleme betrachtet, zu denen wir entsprechende duale Aufgaben formulieren.
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