Optimal configurations of lines and a statistical application

Motivated by the construction of confidence intervals in statistics, we study optimal configurations of $2^d-1$ lines in real projective space $RP^{d-1}$. For small $d$, we determine line sets that numerically minimize a wide variety of potential functions among all configurations of $2^d-1$ lines through the origin. Numerical experiments verify that our findings enable to assess efficiently the tightness of a bound arising from the statistical literature.Comment: 13 page

Multi-particle interactions within the UrQMD approach

A mechanism for locally density-dependent dynamic parton rearrangement and fusion has been implemented into the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) approach. The same mechanism has been previously built in the Quark Gluon String Model (QGSM). This rearrangement and fusion approach based on parton coalescence ideas enables the description of multi-particle interactions, namely 3 -> 3 and 3 -> 2, between (pre)hadronic states in addition to standard binary interactions. The UrQMD model (v2.3) extended by these additional processes allows to investigate implications of multi-particle interactions on the reaction dynamics of ultrarelativistic heavy ion collisions. The mechanism, its implementation and first results of this investigation are presented and discussed

Two-Dimensional Analytical Modeling of Tunnel-FETs

Basat en un mecanisme de transport de corrent de banda a banda, el túnel-FET és capaç de superar la limitació de pendent sub-llindar física del MOSFET de 60 mV /dec. Per tant, s'ha convertit en un dels dispositius més prometedors per ser el successor del MOSFET clàssic en els últims anys. Aquesta tesi descriu tots els passos necessaris per modelar analíticament un Túnel-FET de doble porta. El model inclou una solució electrostàtica de dues dimensions en totes les regions del dispositiu, el que permet fins i tot simulacions hetero-unió del dispositiu. Per a un comportament més realista del dispositiu, cal tenir en compte el rendiment del dispositiu que limita els perfils de dopatge de forma Gaussiana en les unions del canal. Les expressions per a les probabilitats de túnel de banda a banda i les de Trap-Assisted-Tunneling (TAT) són executades per un enfocament WKB quasi bidimensional. El corrent del dispositiu es calcula mitjançant la teoria de transmissió de Landauer. El model és vàlid per a dispositius de canal curt i les estàncies estan ben comparades amb les dades de simulació TCAD Sentaurus i amb les medicions proporcionades. S'introdueix un modelo general per les flactuacions del dopant aleatoria, que prediu les influencies característiques del dispositiu en el corrent de sortida i el voltatge llindar. El model s'aplica al MOSFET, així com a dispositius TFET.Basado en un mecanismo de transporte de corriente banda a banda, el Tunnel-FET es capaz de superar la limitación de pendiente sub-umbral física del MOSFET de 60 mV/dec. Por lo tanto, esto lo convierte en uno de los dispositivos más prometedores para ser el sucesor del MOSFET clásico en los últimos años. Esta tesis describe todos los pasos necesarios para modelar analíticamente un Tunnel-FET de doble puerta. El modelo incluye una solución electrostática bidimensional en todas las regiones del dispositivo, lo que permite incluso simulaciones de hetero-unión del dispositivo. Para un comportamiento más realista del dispositivo se tiene en cuenta el rendimiento del dispositivo que limita los perfiles de dopaje de forma Gaussiana en las uniones del canal. Las expresiones para las probabilidades de túnel de banda a banda y de Trap-Assisted-Tunneling (TAT) se implementan mediante un enfoque de WKB cuasi bidimensional. La corriente del dispositivo se calcula mediante la teoría de transmisión de Landauer. El modelo es válido para dispositivos de canal corto y las estancias están bien comparadas con los datos de simulación TCAD Sentaurus y con las mediciones proporcionadas. Se introduce un modelo general para las fluctuaciones del dopado aleatorio, que predice las influencias características del dispositivo en la corriente de salida y el voltaje umbral. El modelo se aplica al MOSFET, así como a los dispositivos TFET.Based on a band-to-band current transport mechanism, the Tunnel-FET is able to overcome the physical subthreshold slope limitation of the MOSFET of 60 mV/dec. Therefore, it has become one of the most promising devices to be the successor of the classical MOSFET in the last few years. This thesis describes all necessary steps to analytically model a double-gate Tunnel-FET. The model includes a two-dimensional electrostatic solution in all device regions, which enables even hetero-junction device simulations. Device performance limiting Gaussian-shaped doping profiles at the channel junctions are taken into account for a realistic device behavior. Expressions for the band-to-band and trap-assisted-tunneling probabilities are implemented by a quasi two-dimensional WKB approach. The device current is calculated based on Landauer's transmission theory. The model is valid for short-channel devices and stays is good agreement with the TCAD Sentaurus simulation data and with the provided measurements. A general model for random-dopant-fluctuations is introduced, which predicts characteristic device influences on the output current and threshold voltage. The model is applied to MOSFET, as well as TFET devices

Hanbury-Brown-Twiss interferometry within the UrQMD transport approach

In this thesis, Hanbury-Brown-Twiss (HBT) interferometry is used together with the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) to analyse the time and space structure of heavy-ion collisions. The first chapter after the introduction gives an overview of the different types of models used in the field of heavy-ion collisions and a introduction of the UrQMD model in more detail. The next chapter explains the basics of Hanbury-Brown-Twiss correlations, including azimuthally sensitive HBT (asHBT). Results section: 4. Charged Multiplicities from UrQMD 5. Formation time via HBT from pp collisions at LHC 6. HBT analysis of Pb+Pb collisions at LHC energies 7. HBT scaling with particle multiplicity 8. Compressibility from event-by-event HBT 9. Tilt in non-central collisions 10. Shape analysis of strongly-interacting systems 11. Measuring a twisted emission geometry This thesis covers the standard integrated HBT analyses, extracting the Pratt-Bertsch radii, at LHC energies. The analyses at these energies showed a too soft expansion in UrQMD probably related to the absence of a partonic phase in UrQMD. The most promising results in this thesis at these energies are the restriction of the formation time to a value smaller than 0.8 fm/c and furthermore, the results from the asHBT analyses. In simulations of non-central heavy-ion collisions at energies of Elab= 6, 8 and 30 AGeV the validity of the formulae to calculate the tilt angle via asHBT has been checked numerically, even for the case of non-Gaussian, flowing sources. On this basis has been developed and test in the course of this thesis that allows to measure a scale dependent tilt angle experimentally. The signal should be strongest at FAIR energies.In dieser Arbeit wird Hanbury-Brown-Twiss (HBT) Interferometrie benutzt um im Rahmen des Models „Ultrarelativistische Quanten Molekular Dynamik“ (UrQMD) die Raum und Zeit Geometrie von Schwerionen Kollisionen zu untersuchen. Das erste Kapitel nach der Einleitung gibt einen Überblicke über die verschiedenen Sorten von Modellen, die im Feld zur Beschreibung von Schwerionen Kollisionen genutzt werden. Dabei wird ein besonderer Fokus auf die Beschreibung des UrQMD Modelles gesetzt da dieses für die Untersuchungen in dieser Arbeit verwendet wurde. Das nächste Kapitel gibt eine Einführung in die Grundlagen der HBT Korrelationen und enthält auch einen Abschnitt über azimuthal sensitives HBT (asHBT), welches für diese Arbeit wichtig ist. Resultat Kapitel: 4. Charged Multiplicities from UrQMD 5. Formation time via HBT from pp collisions at LHC 6. HBT analysis of Pb+Pb collisions at LHC energies 7. HBT scaling with particle multiplicity 8. Compressibility from event-by-event HBT 9. Tilt in non-central collisions 10. Shape analysis of strongly-interacting systems 11. Measuring a twisted emission geometry Die Resultat Kapitel enthalten die Standard Analysen zu den HBT bei LHC Energien. Dabei zeigt sich, dass die Expansion des Mediums in UrQMD zu weich ist. Dies hängt wahrscheinlich damit zusammen, dass in UrQMD keine partonische Wechselwirkungsphase vorhanden ist. Die interessantesten Ergebnisse sind zum einen die Beschränkung der Formationszeit auf einen Wert kleiner als 0.8 fm/c und zum anderen die Resultate der asHBT Analysen. In der Simulation von semizentralen Kollisionen bei Energien von Elab= 6, 8 und 30 AGeV wurde die Anwendbarkeit der Formel zur Berechnung des Drehungswinkels im Falle von nicht-Gaußschen Quellen mit Fluss numerisch nachgewiesen. Auf dieser Grundlage haben wir ein Verfahren entwickelt und getestet, das es erlaubt einen skalenabhängigen Drehungswinkel experimentell zu messen. Das Signal für diesen Drehungswinkel sollte bei FAIR Energien am größten sein

Implications on the collision dynamics via azimuthal sensitive HBT from UrQMD : the Seventh Workshop on Particle Correlations and Femtoscopy, September 20 - 24 2011, University of Tokyo, Japan

We explore the shape and orientation of the freezeout region of non-central heavy ion collisions. For this we fit the freezeout distribution with a tilted ellipsoid. The resulting tilt angle is compared to the same tilt angle extracted via an azimuthally sensitive HBT analysis. This allows to access the tilt angle experimentally, which is not possible directly from the freezeout distribution. We also show a systematic study on the system decoupling time dependence on dNch/dh, using HBT results from the UrQMD transport model. In this study we found that the decoupling time scales with (dNch/dh)1/3 within each energy, but the scaling is broken across energies

Length sensing and control for Einstein Telescope Low Frequency

In this paper we describe a feasible length sensing and control scheme for the low frequency interferometers of the Einstein Telescope (ET-LF) along with the techniques used to optimise several optical parameters, including the length of the recycling cavities and the modulation frequencies, using two numerical interferometer simulation packages: Optickle and Finesse. The investigations have suggested the use of certain combinations of sidebands to obtain independent information about the different degrees of freedom

Fighting in women’s clothes The pictorial evidence of Walpurgis in Ms. I.33

Ms. I.33 is not only the oldest of the known fencing treatises in European context, it is also the only one showing a woman fighting equally with contemporary men. The author presents her research about the garments this female fencer wears, including her shirt, dress and overdress, hairstyle and footwear. Special consideration is given to the questions whether Walpurgis wears a belt, the length and hem circumference of her garments as well as the methods of draping them in the way depicted. The results of the analysis are compared with contemporary pictorial and archaeological sources of the early 14th century. Some personal insights gathered by the author while fighting in this kind of clothes shed light on the possibilities of moving without being disturbed by them. The clothes and hairstyle worn by Walpurgis, give clues about her social status and thus help to understand the context and dating of the whole manuscript

Environmental and Social Impact Assessment with Public Participation - A company's view

Environmental and Social Impact Assessments are implemented to examine the consequences of planned actions on the physical-chemical, biological, socioeconomic, social, cultural and biophysical surroundings of individuals and communities. The Assessment process is thereby split into different stages, ending in a written Environmental Impact Statement. Bound by legal obligations, many companies face Impact Assessments for their planned projects. However, there is a considerable lack of empirical investigations on how businesses are affected by Environmental and Social Impact Assessments. Additionally, it must be considered that these processes can have a great influence on single companies concerning the development of business or project plans or on a company’s investments. The key findings show that EIA and SIA play a significant role in the development and design of a project, not only because of legal obligations but also because of the influence of the affected public. The analysis confirms that EIA and SIA have impacts on a company’s work load, strategies and project plans. Public participation is considered to be an important part in their Environmental and Social Impact Assessment processes.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format