We study the zeroth-, first-, and second-order algorithms proposed by Tuncel. The zeroth-order algorithms are the generalization of the classic primal-dual affine-scaling methods, and have a strong connection with the quasi-Newton method. Although the zeroth-order algorithms have the property of strict monotone decrease in both primal and dual objective values, they may not converge. We give an illustrative example as well as an algebraic proof to show that the zeroth-order algorithms do not converge to an optimal solution in some cases. The second-order algorithms use the gradients and Hessians of the barrier functions. Tuncel has shown that all second-order algorithms have a polynomial iteration bound. The second-order algorithms have a range of primal-dual scaling matrices to be chosen. We give a method to construct such a primal-dual scaling matrix. We then analyze a new centrality measure. This centrality measure appeared in both first- and second-order algorithms. We compare the neighbourhood defined by this centrality measure with other known neighbourhoods. We then analyze how this centrality measure changes in the next iteration in terms of the step length and some other information of the current iteration.

Authors: Edina Hrustic & Maria Iverbo Title: Facebook – a virtual meetingplace and a gossipcave Level: BA Thesis in Journalism Location: Linnaeus University Language: Swedish Number of pages: 72 Abstract The aim of our study was to examine the meaning of the social media Facebook for young people who are in the age of 16 to 25 years. We wanted to gain an understanding in the youths´ thoughts and beliefs of how Facebook exists and plays a role in their lives. As a result from this research, we discussed how social media might affect the future of journalism. We formed our thesis based on research of the digital network society, social networks, the youth culture, and how the target group; the young people use and experience social media. We made a questionnaire for 36 high school students, and three of these participated in a focusgroup-discussion. We combined and analyzed the response from the questionnaire and the focus group in our final result, and discussed patterns and relations between the youngsters´ answers. Our result shows that Facebook mostly is regarded to be a virtual meetingplace, where these young people can interact and communicate with each other. They mostly communicate with their friends from the real-life, and youths´ use Facebook as a tool when they want to find out what people in their surrounding do. The questionnaire result also shows that Facebook can be seen as an information channel, where the young people can get gossip and offer each other invitations to common events. From this study, we can point out that the social network is practically of great importance in young peoples’ lives. The questionnaire of Facebook and how young people´s habits are affected implies that it is important to use the social network discussion while analysing the convergence between so called; "old" and "new media". Young people steer and direct the use of media, and that is the reason why the understanding about their thoughts of social media is significantly important. One could practically say that youngsters can affect the future of journalism, and the design and development of media. Key words: young people, Facebook, social media, virtual communication, the convergence of media, digital network society, journalism

Wikipedia, ”den fria encyklopedin som alla kan redigera”, används mer och mer. Den är tillräckligt stor för att konkurrera med traditionella uppslagsverk som Encyclopedia Britannica eller Nationalencyklopedin. Den stora skillnaden jämfört med de traditionella uppslagsverken är dock att även de som inte är experter kan redigera och skriva artiklar. Wikipedia, som den ”vanlige internetanvändaren” kan påverka innehållet i, är en del av vad man kan kalla för deltagarkultur. Internetmediets struktur skapar förutsättningar för att användaren interaktivt ska kunna delta, och den här förutsättningen har hjälpt till att snabbt skapa ett stort uppslagsverk på internet. På grund av kritiken som riktats mot Wikipedia om huruvida det går att lita på uppslagsverket, undersöks i den här uppsatsen debatten kring vem som borde ha rätt att bestämma vad som ska få vara kunskap på Wikipedia och utifall det krävs ett tydligare regelverk kring hur kunskapsprocessen går till. Metoden som används är diskursanalys och resultatet visar att den traditionella synen på kunskap med expertis i fokus inte har spelat ut sin roll.

Stochastic sampling methods are ubiquitous in statistical mechanics, Bayesian statistics, and theoretical computer science. However, when the distribution that is being sampled is multimodal, many of these techniques converge slowly, so that a great deal of computing time is necessary to obtain reliable answers. Parallel and simulated tempering are sampling methods that are designed to converge quickly even for multimodal distributions. In this thesis, we assess the extent to which this goal is acheived.We give conditions under which a Markov chain constructed via parallel or simulated tempering is guaranteed to be rapidly mixing, meaning that it converges quickly. These conditions are applicable to a wide range of multimodal distributions arising in Bayesian statistical inference and statistical mechanics. We provide lower bounds on the spectral gaps of parallel and simulated tempering. These bounds imply a single set of sufficient conditions for rapid mixing of both techniques. A direct consequence of our results is rapid mixing of parallel and simulated tempering for several normal mixture models in R^M as M increases, and for the mean-field Ising model.We also obtain upper bounds on the convergence rates of parallel and simulated tempering, yielding a single set of sufficient conditions for torpid mixing of both techniques. These conditions imply torpid mixing of parallel and simulated tempering on a normal mixture model with unequal covariances in $\R^M$ as $M$ increases and on the mean-field Potts model with $q \geq 3$, regardless of the number and choice of temperatures, as well as on the mean-field Ising model if an insufficient (fixed) set of temperatures is used. The latter result is in contrast to the rapid mixing of parallel and simulated tempering on the mean-field Ising model with a linearly increasing set of temperatures. / Dissertation

<p>The dissertation focuses on solving some important theoretical and methodological problems associated with Bayesian modeling of infinite dimensional `objects', popularly called nonparametric Bayes. The term `infinite dimensional object' can refer to a density, a conditional density, a regression surface or even a manifold. Although Bayesian density estimation as well as function estimation are well-justified in the existing literature, there has been little or no theory justifying the estimation of more complex objects (e.g. conditional density, manifold, etc.). Part of this dissertation focuses on exploring the structure of the spaces on which the priors for conditional densities and manifolds are supported while studying how the posterior concentrates as increasing amounts of data are collected.</p><p>With the advent of new acquisition devices, there has been a need to model complex objects associated with complex data-types e.g. millions of genes affecting a bio-marker, 2D pixelated images, a cloud of points in the 3D space, etc. A significant portion of this dissertation has been devoted to developing adaptive nonparametric Bayes approaches for learning low-dimensional structures underlying higher-dimensional objects e.g. a high-dimensional regression function supported on a lower dimensional space, closed curves representing the boundaries of shapes in 2D images and closed surfaces located on or near the point cloud data. Characterizing the distribution of these objects has a tremendous impact in several application areas ranging from tumor tracking for targeted radiation therapy, to classifying cells in the brain, to model based methods for 3D animation and so on. </p><p> </p><p> The first three chapters are devoted to Bayesian nonparametric theory and modeling in unconstrained Euclidean spaces e.g. mean regression and density regression, the next two focus on Bayesian modeling of manifolds e.g. closed curves and surfaces, and the final one on nonparametric Bayes spatial point pattern data modeling when the sampling locations are informative of the outcomes.</p> / Dissertation

<p>Identifying a lower-dimensional latent space for representation of high-dimensional observations is of significant importance in numerous biomedical and machine learning applications. In many such applications, it is now routine to collect data where the dimensionality of the outcomes is comparable or even larger than the number of available observations. Motivated in particular by the problem of predicting the risk of impending diseases from massive gene expression and single nucleotide polymorphism profiles, this dissertation focuses on building parsimonious models and computational schemes for high-dimensional continuous and unordered categorical data, while also studying theoretical properties of the proposed methods. Sparse factor modeling is fast becoming a standard tool for parsimonious modeling of such massive dimensional data and the content of this thesis is specifically directed towards methodological and theoretical developments in Bayesian sparse factor models.</p><p>The first three chapters of the thesis studies sparse factor models for high-dimensional continuous data. A class of shrinkage priors on factor loadings are introduced with attractive computational properties, with operating characteristics explored through a number of simulated and real data examples. In spite of the methodological advances over the past decade, theoretical justifications in high-dimensional factor models are scarce in the Bayesian literature. Part of the dissertation focuses on exploring estimation of high-dimensional covariance matrices using a factor model and studying the rate of posterior contraction as both the sample size & dimensionality increases. </p><p>To relax the usual assumption of a linear relationship among the latent and observed variables in a standard factor model, extensions to a non-linear latent factor model are also considered.</p><p>Although Gaussian latent factor models are routinely used for modeling of dependence in continuous, binary and ordered categorical data, it leads to challenging computation and complex modeling structures for unordered categorical variables. As an alternative, a novel class of simplex factor models for massive-dimensional and enormously sparse contingency table data is proposed in the second part of the thesis. An efficient MCMC scheme is developed for posterior computation and the methods are applied to modeling dependence in nucleotide sequences and prediction from high-dimensional categorical features. Building on a connection between the proposed model & sparse tensor decompositions, we propose new classes of nonparametric Bayesian models for testing associations between a massive dimensional vector of genetic markers and a phenotypical outcome.</p> / Dissertation

The objective of this research has been the study of device properties for emerging wide-bandgap cubic-phase semiconductors. Though the wide-bandgap semiconductors have great potential as high-power microwave devices, many gaps remain in the knowledge about their properties. The simulations in this work are designed to give insight into the performance of microwave high-power devices constructed from the materials in question. The simulation are performed using a Monte Carlo simulator which was designed from the ground up to include accurate, numerical band structures derived from an empirical pseudo-potential model. Improvements that have been made to the simulator include the generalized device structure simulation, the fully numerical final state selector, and the inclusion of the overlap integrals in the final-state selection. The first comparison that is made among the materials is direct-current breakdown. The DC voltage at which breakdown occurs is a good indication of how much power a transistor can provide. It is found that GaAs has the smallest DC breakdown, with 3C-SiC and ZB-GaN being over 3 times higher. This follows what is expected and is discussed in detail in the work. The second comparison made is the radio-frequency breakdown of the transistors. When devices are used in high-frequency applications it is possible to operate them beyond DC breakdown levels. This phenomenon is caused by the reaction time of the carriers in the device. It is important to understand this effect if these materials are used in a high-frequency application, since this effect can cause a change in the ability of a material to produce high-power devices. MESFETs made from these materials are compared and the results are discussed in detail.

In this dissertation we first formulate the Black-Scholes equation with a tensor (or matrix) diffusion coefficient into a conservative form and present a convergence analysis for the two-dimensional Black-Scholes equation arising in the Hull-White model for pricing European options with stochastic volatility. We formulate a non-conforming Petrov-Galerkin finite element method with each basis function of the trial space being determined by a set of two-point boundary value problems defined on element edges. We show that the bilinear form of the finite element method is coercive and continuous and establish an upper bound of order O(h) on the discretization error of method, where h denotes the mesh parameter of the discretization. We then present a finite volume method for the resulting equation, based on a fitting technique proposed for a one-dimensional Black-Scholes equation. We show that the method is monotone by proving that the system matrix of the discretized equation is an M-matrix. Numerical experiments, performed to demonstrate the usefulness of the method, will be presentd.

We consider the problem of finding a common fixed point of an infinite family ${T_n}$ of nonlinear self-mappings of a closed convex subset $C$ of a real Hilbert space $H$. Namely, we want to find a point $x$ with the property (assuming such common fixed points exist): [ xin igcap_{n=1}^infty ext{Fix}(T_n). ] We will use the Krasnoselskii-Mann (KM) Type inertial iterative algorithms of the form $$ x_{n+1} = ((1-alpha_n)I+alpha_nT_n)y_n,quad y_n = x_n + eta_n(x_n-x_{n-1}).eqno(*)$$ We discuss the convergence properties of the sequence ${x_n}$ generated by this algorithm (*). In particular, we prove that ${x_n}$ converges weakly to a common fixed point of the family ${T_n}$ under certain conditions imposed on the sequences ${alpha_n}$ and ${eta_n}$.

ABSTRACT ¡uDigital convergence¡v-which is normally being regarded as integrate telecommunication¡Binternet and cable television industries these 3 originally independent industries¡Ahad caused structural changes to related industries such as Information Technologies (IT)¡Btelecommunication¡Bconsumer electronics and entertainment medias¡CDue to this new technology¡¦s innovation¡Achanges not only happened on the company¡¦s developing policy and core product but also impacted to company¡¦s¡¦ internal organizational structure ¡C In order to react to these challenges coming with digital convergence age¡A F. telecommunication company that I work in decided to launch an organization integration to conform the related mobile telecommunication¡Bfixed cable line and internet industry within our business group to get the new growth resource¡C In fact this organizational integration has same meaning as outside business merge though we all belongs to the same business group since old burden problems of different business culture¡Bprocess management and organizational conflicts that originally existed ¡A the purpose of organizational integration can not be immediately reached obviously¡C However Network Technology (NT ) - my working department ¡V have a implementation plan name ¡§ I-Care project ¡§ in this turmoil period ¡Ahopefully mold new NT organization into Customer-Accountability-Responsive-Execution caring core values¡Awhich emphasis mindset change evolution form inside to outside opinions¡C This study research focus on ¡§ i-Care¡¦ project ¡V an organization learning model - how employees look at this mindset change evolution while working scope change substantially after organization integration . During the research process¡A I worked out the root reason why NT insist on ¡¥ i-Care ¡§ plan that organizational conflict happened between NT and Sales department¡A it caused customers¡¦ satisfaction descend ¡Bcognitive divergence on department value and confronting position on daily working process durther problems ¡CAfter 1 year implementation of ¡§ i-Care ¡§¡A the achievement includes NT employees not only clarify their technical value but also service and making new added value¡Alearned how to make efficient communication with interior customers- sales and exterior customers¡Aattracted new organizational centripetal force quickly¡Aand provide mitigation to organization conflict solution to make greater customer satisfaction ¡CFinally , provide few opinions of key successful points on organization learning like ¡§ i-Care ¡§ from my research observation for this study conclusion¡C Key words : Digital convergence¡Borganization integration¡BI-Care project¡Bmindset change¡Borganization learning