We investigate the numerical solution of stable Sylvester equations via iterative schemes proposed for computing the sign function of a matrix. In particular, we discuss how the rational iterations for the matrix sign function can efficiently be adapted to the special structure implied by the Sylvester equation. For Sylvester equations with factored constant term as those arising in model reduction or image restoration, we derive an algorithm that computes the solution in factored form directly. We also suggest convergence criteria for the resulting iterations and compare the accuracy and performance of the resulting methods with existing Sylvester solvers. The algorithms proposed here are easy to parallelize. We report on the parallelization of those algorithms and demonstrate their high efficiency and scalability using experimental results obtained on a cluster of Intel Pentium Xeon processors.

We investigate the solution of large-scale generalized algebraic Bernoulli equations as those arising in control and systems theory in the context of stabilization of linear dynamical systems, coprime factorization of rational matrix-valued functions, and model reduction. The algorithms we propose, based on a generalization of the Newton iteration for the matrix sign function, are easy to parallelize, yielding an efficient numerical tool to solve large-scale problems. Both the accuracy and the parallel performance of our implementations on a cluster of Intel Xeon processors are reported.

We discuss a parallel library of efficient algorithms for the solution of linear-quadratic optimal control problems involving largescale systems with state-space dimension up to $O(10^4)$. We survey the numerical algorithms underlying the implementation of the chosen optimal control methods. The approaches considered here are based on invariant and deflating subspace techniques, and avoid the explicit solution of the associated algebraic Riccati equations in case of possible ill-conditioning. Still, our algorithms can also optionally compute the Riccati solution. The major computational task of finding spectral projectors onto the required invariant or deflating subspaces is implemented using iterative schemes for the sign and disk functions. Experimental results report the numerical accuracy and the parallel performance of our approach on a cluster of Intel Itanium-2 processors.

The purpose of our examination paper is to examine, describe and analyze preschool teacher ́s knowledge about manual signing in a preschool setting. Furthermore, we want to examine if preschools teacher ́s use manual signing in Swedish preschool ́s in a pedagogically purpose. The questions that we want to answer with our work is if preschool teachers are aware about the sign language used in Swedish schools and if they use manual signs for pedagogically purposes or not. Our data was gathered from four different preschools in the Stockholm region, where both interviews and observations were conducted to study the aim of our paper. Seven different preschool teachers participated in the interviews and we observed the environment in the different preschools. Our theoretic basis for our paper is Säljö ́s perspective on Vygotsky's sociocultural theory. The part of the theory that are most relevant for our work and that we use in our analysis are communicative interaction, artefacts and mediation. We also base our work on earlier research done by Skans about the preschools didactic practices and by DiCarlo et al. about effect on manual signing on communicative verbalizations in inclusive classrooms. With the help of our analysis we can make different conclusions about preschool teachers work with manual signing. One such conclusion is that there is an awareness among preschool teachers about the manual signing. All of the teachers that participated in our interviews work in one way or another with manual signing in a pedagogically purpose. Beside the manual signing the preschool teachers also use different alternative communicative methods. There is a positive attitude among the preschool teachers to use alternative communicative methods with children in a pedagogical purpose.

As data become more pervasive and computing power increases, the opportunity for transformative use of data grows. Collecting data from individuals can be useful to the individuals (by providing them with personalized predictions) and the data collectors (by providing them with information about populations). However, collecting these data is costly: answering survey items, collecting sensed data, and computing values of interest deplete finite resources of time, battery, life, money, etc. Dynamically ordering the items to be collected, based on already known information (such as previously collected items or paradata), can lower the costs of data collection by tailoring the information-acquisition process to the individual. This thesis presents a framework for an iterative dynamic item ordering process that trades off item utility with item cost at data collection time. The exact metrics for utility and cost are application-dependent, and this frame- work can apply to many domains. The two main scenarios we consider are (1) data collection for personalized predictions and (2) data collection in surveys. We illustrate applications of this framework to multiple problems ranging from personalized prediction to questionnaire scoring to government survey collection. We compare data quality and acquisition costs of our method to fixed order approaches and show that our adaptive process obtains results of similar quality at lower cost. For the personalized prediction setting, the goal of data collection is to make a prediction based on information provided by a respondent. Since it is possible to give a reasonable prediction with only a subset of items, we are not concerned with collecting all items. Instead, we want to order the items so that the user provides information that most increases the prediction quality, while not being too costly to provide. One metric for quality is prediction certainty, which reflects how likely the true value is to coincide with the estimated value. Depending whether the prediction problem is continuous or discrete, we use prediction interval width or predicted class probability to measure the certainty of a prediction. We illustrate the results of our dynamic item ordering framework on tasks of predicting energy costs, student stress levels, and device identification in photographs and show that our adaptive process achieves equivalent error rates as a fixed order baseline with cost savings up to 45%. For the survey setting, the goal of data collection is often to gather information from a population, and it is desired to have complete responses from all samples. In this case, we want to maximize survey completion (and the quality of necessary imputations), and so we focus on ordering items to engage the respondent and collect hopefully all the information we seek, or at least the information that most characterizes the respondent so imputed values will be accurate. One item utility metric for this problem is information gain to get a “representative” set of answers from the respondent. Furthermore, paradata collected during the survey process can inform models of user engagement that can influence either the utility metric ( e.g., likelihood therespondent will continue answering questions) or the cost metric (e.g., likelihood the respondent will break off from the survey). We illustrate the benefit of dynamic item ordering for surveys on two nationwide surveys conducted by the U.S. Census Bureau: the American Community Survey and the Survey of Income and Program Participation.

A perturbation analysis shows that if a numerically stable procedure is used to compute the matrix sign function, then it is competitive with conventional methods for computing invariant subspaces. Stability analysis of the Newton iteration improves an earlier result of Byers and confirms that ill-conditioned iterates may cause numerical instability. Numerical examples demonstrate the theoretical results.

This c-level essay examines how deaf and hearing impaired individuals use smartphones to live and communicate in a “hearing world”. The main target is to find some understanding of the struggles of this population and smartphones have made it easier to adapt to the hearing worlds’ demands with the applications that follow. To acquire the information for this essay, representatives from both the deaf and hearing impaired communities were interviewed. The findings of this qualitative study show that there are many applications that have advantages to aid the lives of deaf and hearing impaired. These include WhatsApp, Tango and many others. All of the respondents appreciated the new technology but also said that there is work to be done in that area. Especially the poor quality of the video calls is not satisfactory to the users using sign language.

Detta arbete undersöker ett par olika tekniker för att implementera single sign on med Kerberos i webbapplikationer. Undersökningen har gjorts på HTTP-autentisering som bygger på Microsofts NegotiateAuth och Cosign från University of Michigan. Dessa två tekniker har undersökts för att se hur de står sig mot varandra på kriterier såsom komplexitet, arbetsinsats och mjukvarukrav.Resultatet visar att HTTP-autentisering är väldigt simpel att implementera men kräver dock att användarens webbläsare konfigureras för den. Cosign är mer komplext men använder sig av Cookies vilket gör att de flesta webbläsare stödjer tekniken utan extra konfiguration.

Motivation is an important factor when it comes to learning a language, including the Deaf and hard of hearing pupils. The purpose of this investigation is to investigate whether Deaf and hard of hearing pupils in Sweden are motivated to learn a foreign language, i.e. English, and whether the motivation is an intrinsic or extrinsic kind. The aim of this study is to contribute with extended knowledge and an in-depth understanding of motivation to learn a foreign language among Deaf and hard of hearing pupils, since no research of this kind has been conducted in Sweden, so far. The investigation was conducted through semi-structured interviews in Swedish Sign language about the motivation to learn a foreign language, and the findings showed that many of the pupils are motivated to learn English. The factors that affect their motivation are studying or working abroad, communicating with people from other countries and understanding information when travelling around the world. Another significant finding was a wish to learn an International Sign language in the school as a complement to the subject English to be eligible to communicate with Deaf people from other countries.

The goal of the project was to create an extension to Internet Explorer forStatens Tjänstepensionsverk (SPV) which would give the staff the experience ofSingle sign-on (SSO) to external web service providers as well as manage andupdate their passwords in a secure manner. The survey focused on the providersPalasso, ProCompetence and Wera. The extension was created as a BrowserHelper Object (BHO) with C# in .NET. The solution was implemented as aCOM object in a DLL-file that was running in-process with the browser. Theprogram used a locally stored XML file containing URLs, usernames andencrypted passwords to the providers. When a user came to a login page theprogram collected the HTML elements on the page and populated them withdata from the file and logged in the user. Encryption and decryption was solvedwith a symmetric key that was stored in the program. In the XML file was alsothe date for the latest update of the password. If one month had passed, theprogram either gave the user an indication that the password needed to beupdated, or updated it automatically with a new generated password, dependingon the provider. The conclusion was that the extension worked as planned butthat there were improvements to be made regarding the possibility to add newsites to the system. The project also included an analysis of alternative optionsto solve the problem using JavaScript, Add-in Express, or via a portal page. Theconclusion was that none of these were an equally powerful tool as a BHO.