956 research outputs found

    Search for excited spin-3/2 neutrinos at LHeC

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    We study the potential of the next epep collider, namely LHeC, with two options s=1.3\sqrt{s}=1.3 TeV s=1.98\sqrt{s}=1.98 TeV, to search for excited spin-1/2 and spin-3/2 neutrinos. We calculate the single production cross section of excited spin-1/2 and spin-3/2 neutrinos according to their effective currents describing their interactions between gauge bosons and SM leptons. We choose the νeW\nu^{\star}\rightarrow eW decay mode of excited neutrinos and WjjW\rightarrow jj decay mode of WW-boson for the analysis. We put some kinematical cuts for the final state detectable particles and plot the invariant mass distributions for signal and the corresponding backgrounds. In order to obtain accessible limits for excited neutrino couplings, we show the fff-f^{\prime} and ciVciAc_{iV}-c_{iA} contour plots for excited spin-1/2 and excited spin-3/2 neutrinos, respectively.Comment: 15 pages, 8 figures, 5 Table

    Search for HZZHZZ' couplings at the LHC

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    New physics models predict the possibility of extra neutral gauge bosons (ZZ') associated with an extra U(1)U(1)' gauge symmetry. We study the couplings of the Higgs boson to the ZZ boson and ZZ' boson predicted by the new physics models. The couplings of the ZZ' boson to quarks can also be investigated through the ZqqˉZ'q\bar{q} interactions. The accessible ranges of the parameter space have been searched for processes ppHZXpp\rightarrow HZX and ppHHZXpp\rightarrow HHZX at the LHC with s=14\sqrt{s}=14 TeV.Comment: 10 pages, 10 figure

    Optimal ship navigation and algorithms for stochactic obstacle scenes

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    Tezin basılısı İstanbul Şehir Üniversitesi Kütüphanesi'ndedir.This thesis is comprised of two different but related sections. In the first section, we consider the optimal ship navigation problem wherein the goal is to find the shortest path between two given coordinates in the presence of obstacles subject to safety distance and turn-radius constraints. These obstacles can be debris, rock formations, small islands, ice blocks, other ships, or even an entire coastline. We present a graph-theoretic solution on an appropriately-weighted directed graph representation of the navigation area obtained via 8-adjacency integer lattice discretization and utilization of the A∗ algorithm. We explicitly account for the following three conditions as part of the turn-radius constraints: (1) the ship’s left and right turn radii are different, (2) ship’s speed reduces while turning, and (3) the ship needs to navigate a certain minimum number of lattice edges along a straight line before making any turns. The last constraint ensures that the navigation area can be discretized at any desired resolution. We illustrate our methodology on an ice navigation example involving a 100,000 DWT merchant ship and present a proof- of-concept by simulating the ship’s path in a full-mission ship handling simulator at Istanbul Technical University. In the second section, we consider the stochastic obstacle scene problem wherein an agent needs to traverse a spatial arrangement of possible-obstacles, and the status of the obstacles may be disambiguated en route at a cost. The goal is to find an algorithm that decides what and where to disambiguate en route so that the expected length of the traversal is minimized. We present a polynomial-time method for a graph-theoretical version of the problem when the associated graph is restricted to parallel avenues with fixed policies within the avenues. We show how previously proposed algorithms for the continuous space version can be adapted to a discrete setting. We propose a gener- alized framework encompassing these algorithms that uses penalty functions to guide the navigation in realtime. Within this framework, we introduce a new algorithm that provides near-optimal results within very short execution times. Our algorithms are illustrated via computational experiments involving synthetic data as well as an actual naval minefield data set. Keywords: Graph theory, shortest path, ship navigation, probabilistic path planning, stochastic dynamic programming, Markov decision process, Canadian traveler’s problemContents Declaration of Authorship ii Abstract iv ¨ Oz v Acknowledgments vii List of Figures x List of Tables xi 1 Optimal Ship Navigation with Safety Distance and Realistic Turn Con- straints 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Previous Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 The Optimal Ship Navigation Problem . . . . . . . . . . . . . . . . . . . . 4 1.4 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4.1 Safety Distance Constraints . . . . . . . . . . . . . . . . . . . . . . 5 1.4.2 Lattice Discretization . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4.3 Ship-Turn Constraints . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.4.4 The A∗ Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4.5 Smoothing the Optimal Path . . . . . . . . . . . . . . . . . . . . . 13 1.5 Ice Navigation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.6 Simulator Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.7 Summary, Conclusions, and Future Research . . . . . . . . . . . . . . . . 18 2 Algorithms for Stochastic Obstacle Scenes 21 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2 The Stochastic Obstacle Scene Problem: Continuous vs. Discrete Settings 23 2.2.1 Deciding Where to Disambiguate: Single Disk Case . . . . . . . . 23 2.2.2 Deciding Where to Disambiguate: Two Disks Case . . . . . . . . . 25 2.2.3 Discretization of the Continuous Setting: An Example . . . . . . . 27 2.3 Definition of the Stochastic Obstacle Scene Problem . . . . . . . . . . . . 27 2.3.1 Continuous SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.2 Discrete SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.3 Discretized SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.4 A Polynomial Algorithm for Discrete SOSP on Parallel Graphs . . . . . . 29 2.5 Discrete Adaptation of the Simulated Risk Disambiguation Algorithm . . 30 2.5.1 Adaptation to Discrete SOSP . . . . . . . . . . . . . . . . . . . . . 30 2.5.2 Adaptation to Discretized SOSP . . . . . . . . . . . . . . . . . . . 32 2.6 Discrete Adaptation of the Reset Disambiguation Algorithm . . . . . . . . 33 2.7 Generalizing SRA and RDA: Penalty-Based Algorithms and DTA . . . . . 34 2.7.1 Illustration of the Algorithms . . . . . . . . . . . . . . . . . . . . . 36 2.8 Computational Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.8.1 Environment A (The COBRA Data) Experiments . . . . . . . . . 40 2.8.2 Environment B Experiments . . . . . . . . . . . . . . . . . . . . . 41 2.8.3 Environment C Experiments . . . . . . . . . . . . . . . . . . . . . 43 2.9 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 A Impact of Cost Change in Parallel Graphs 47 Bibliograph

    The biography and multivalence of sacred silver objects in the sixth-century sion treasure

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    The aim of this thesis is to demonstrate that the sacred silver objects from the sixth-century Sion treasure had different biographies and multivalences in different contexts. By this I mean that these objects had different conceptual dimensions in their production and usage in sixth-century Byzantium. These different meanings were a result of the changing interrelationships between people and the objects, depending on the intention and functionality of the objects and the contexts in which they were used. I will highlight three main aspects, all closely related. The first is the question of the changing function of the silver treasure: as commodity for sale; as a gift to God; as used inside the church for liturgical performances or as decorative church revetments. Tied to this is the intention of its users, something developed through ritual and knowledge, which gave the treasure its intended function – which relates to its functionality and the contexts in which it was used. These contexts enabled the users of the silverware to perceive these objects in different ways and give them meanings and life-stories, or biographies. For example, when a worshipper inside the church engaged with a paten, say, their reading and valuing of that object was not that which the donors perceived when they gave it as a gift. My examination is carried out with a focus on the fifty-two silver objects from the Sion treasure which I have examined in Antalya Museum in Turkey and the Dumbarton Oaks Collection in Washington DC. Relying on my examinations in these two collections, the arguments in this thesis will be based on the forms, inscriptions, decorations, stamps and monograms on the objects. My thesis will discuss both what the value of the silverware was to its producers, donors and what its value might have been to those using these objects inside the church, not only to clergy but also to lay worshippers

    Electronic, spintronic and transport properties og carbon based nanowires

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    Thesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2011Includes bibliographical references (leaves: 64-77)Text in English; Abstract: Turkish and Englishxii, 77 leavesIn this thesis, properties of carbon based nanowires are studied by ab-initio calculations. The aim is to gain a thorough understanding of the electronic, spintronic, transport properties in nanowires and how they are affected by different geometric formations, defects and adatom adsorptions. To this end the non-equilibrium Green's function formalism with first principles pseudopotential density functional theory calculations have been used to describe spin-polarized systems. Firstly, different geometric formations of Cobalt-Benzene nanowires are investigated. Systems with ferromagnetic ordering are calculated as half-metallic while systems with antiferromagnetic ordering behave as metallic. Also the results of the spin polarized current calculations indicate that one of the spin components of current is dominant for the antiferromagnetic systems while both spin components of current are dominant in different bias windows of a specific total applied bias. As second case, alkali atom termination of the zigzag graphene nanoribbons (ZGNR) are studied. In particular, using sodium atoms for the saturation of ZGNR edges at half the concentration of edge-carbon atoms make it a one dimensional, perfect semimetal, where the valance and conduction bands meet at only a single, Dirac-like point. Unlike pristine graphene, the Dirac-"cones" of Na-ZGNR is not symmetric with respect to wave vector, but rather it is tilted. Finally, adsorption up to the graphenic sheets with periodic 5-8 defects is studied. Especially, electronic structure of the V adsorption into 5-8 defects induced graphenic sheets are calculated as half-metallic while formation of linear bands crossing at the Fermi level which form a tilted Dirac cone

    Anomalous WWγWW\gamma couplings with beam polarization at the Compact Linear Collider

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    We study the anomalous WWγWW\gamma couplings at the Compact Linear Collider through the processes e+eW+We^{+}e^{-}\to W^+W^-, ee+eγe+e+νeWe^{-}e^{+} \to e^{-} \gamma^{*} e^{+} \to e^{+} \nu_{e} W^- and ee+eγγe+eW+We+e^{-}e^{+}\to e^{-} \gamma^{*} \gamma^{*} e^{+} \to e^{-} W^+ W^- e^{+} (γ (\gamma^{*} is the Weizsacker-Williams photon). We give the 95\% confidence level limits for unpolarized and polarized electron (positron) beam on the anomalous couplings for various values of the integrated luminosities and center-of-mass energies. We show that the obtained limits on the anomalous couplings through these processes can highly improve the current experimental limits. In addition, our limits with beam polarization are approximately two times better than the unpolarized case.Comment: Tables and references adde

    Cognitive schemas and attachment

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    People show similar reactions to similar stimulants but they may show different reactions as well. We are all very similar and yet very different. As expressed in many psychological theories, each person is "unique and different". Everyone feels pain when they lose the person they love. However, everyone experiences their own pain in different ways. There are many psychological theories that explain the reason for different behavioral and emotional responses to similar stimulants. While behavioral theory explains how people behave focusing on learning experiences, the psychoanalytic theory explains the behavioral differences with the individual's instincts and drives. On the other hand, cognitive psychologists accept that although the stimulants are similar, the perception of the individuals differs. Humanistic psychologists accept that human nature as positive but the environmental circumstances such as education, parental issues may lead negative behaviors. It is possible to expand these views on this topic. Based on the theory to understand the behaviour, by putting some limitations in order to study and to observe the behaviour easily, complex approaches work on some concepts such as love, anger, angression etc. To study and understand the close relationships is one of the subjects that are still being tried to be understood due to its contributions to the theoretical field and the field of practice. One of the most important works in the field to understanding interpersonal close relationships is Bowlby's "Attachment Theory". On the other hand, the views of Young (1990), who explained adaptation or maladaptive behaviors with "Early Schemas" in the last two decades, brought up the question of whether attachment or schemas are effective in close relationships. The review discussion in this topic is given below

    Bravo Semiha Berksoy'a!

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    Taha Toros Arşivi, Dosya No: 134-Semiha-Zeliha BerksoyUnutma İstanbul projesi İstanbul Kalkınma Ajansı'nın 2016 yılı "Yenilikçi ve Yaratıcı İstanbul Mali Destek Programı" kapsamında desteklenmiştir. Proje No: TR10/16/YNY/010
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