This paper is concerned with the numerical analysis of the autoconvolution equation $x*x=y$ restricted to the interval [0,1]. We present a discrete constrained least squares approach and prove its convergence in $L^p(0,1),1<p<\infinite$ , where the regularization is based on a prescribed bound for the total variation of admissible solutions. This approach includes the case of non-smooth solutions possessing jumps. Moreover, an adaption to the Sobolev space $H^1(0,1)$ and some remarks on monotone functions are added. The paper is completed by a numerical case study concerning the determination of non-monotone smooth and non-smooth functions x from the autoconvolution equation with noisy data y.

Responsible Sourcing is gaining growing importance for companies willing to demonstrate responsibility and commitment to sustainable practices. Sourcing is a key element of supply chain management and by adopting responsible sourcing practices, companies can greatly contribute to the sustainability of their entire supply chains. Being close to both customers and suppliers, retailers hold a particularly influential position in the supply chain and their sourcing choices can play a key role for sustainability improvements. This paper investigates the different strategies that can be adopted to guarantee responsible sourcing in the retail sector, through the specific case study of two UK retailers, Sainsbury´s and Tesco, and their offer of sustainable seafood. Specifically, the relation between the offer of MSC certified products and the retailers´ commitment to source responsibly is here analysed. The main source of data collection is a content analysis of retailers´ CSR online reports and web pages. Additional information is obtained through reports and web pages’ analysis of four UK organizations dealing with sustainable seafood issues. The findings of the study suggest that the offer of MSC certified products is positively correlated with the adoption of responsible sourcing practices; different strategies are available to retailers to guarantee responsible sourcing and that retailers´ sourcing policies can be influenced by other stakeholders´ guidelines for responsible sourcing.

Two-periodic random walks are models for the one-dimensional motion of particles in which the jump probabilities depend on the parity of the currently occupied state. Such processes have interesting applications, for instance in chemical physics where they arise as embedded random walk of a special queueing problem. In this paper we discuss in some detail first passage time problems of two-periodic walks, the distribution of their maximum and the transition functions when the motion of the particle is restricted by one or two absorbing boundaries. As particular applications we show how our results can be used to derive the distribution of the busy period of a chemical queue and give an analysis of a somewhat weird coin tossing game. / Series: Research Report Series / Department of Statistics and Mathematics

The goal of this project was to determine the key regulators of Mesenchymal Stromal Cell (MSC) potency as part of a cell-based therapy to treat inflammatory and autoimmune diseases. The immunomodulatory capacity of MSCs is dictated by multiple, interacting conditions that take place during the biomanufacturing of these cells, as well as after they are transplanted. Variables such as the source of MSCs and the inflammatory cues in their microenvironment are critical regulators of potency that can be manipulated and optimized prior to their use for an enhanced cell-based therapy. Herein, I took a systematic approach to isolating a single variable in the microenvironment of MSCs to determine its effect on the key immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO). I then manipulated these variables and applied them across multiple MSC donors to determine how their effect varied between cells isolated from different individuals. Finally, I conducted an in vitro potency assay with MSCs and Peripheral Blood Mononuclear Cells (PBMCs) to determine how enhanced IDO due to these variables translated to immune suppression for an enhanced cell product. Upon transplantion, different disease settings have altered microenvironments that can hinder the efficacy of an MSC therapy. The microenvironment in obesity and type 2 diabetes (T2D) has elevated levels of the fatty acid palmitate which shifts the phenotype of MSCs from immune suppressive to pro-inflammatory. I demonstrated that manipulating the microenvironment of MSCs to enhance IDO protein concentration prior to transplant reverses the pro-inflammatory effects of palmitate and restores immune suppression by MSCs. My finding was that the appropriate environmental cues, along with a potent donor, yields a cell-based therapy that can overcome challenges in many disease settings such as obesity and T2D.

The purpose of this study was to identify conditioning strategies for mesenchymal stromal cells (MSC) which optimize cellular immunosuppressive potency. By identifying new treatment strategies and previously unidentified small molecules capable of stimulating MSC we hope to pave the way tailoring licensed MSC phenotypes to be used in a specific disease state, rather than a one size fits all package. We sought to determine how MSC act in response to a changing immune response or environmental condition. MSC are exquisitely sensitive to changes in their environmental conditions and we show that cellular transcriptome and secretome changes are conditionally responsive to their inflammatory stimulus. One of the main subjects of analysis here is the observations of how these cellular profiles evolve over time in the presence of an inflammatory environment. Similarly, this study observes how MSC behavior changes after an inflammatory event has been resolved to address, in part, the plasticity of MSC licensing and the ability of MSC to rapidly recall a previous immunosuppressive state upon secondary challenge with an inflammatory stimulus. Data was obtained from in vitro experiments with human bone marrow derived MSC and donor human peripheral blood mononuclear cells (PBMC), while in vivo data was obtained using C57BL6/J mice. Overall this research demonstrated that MSC potency can be bolstered by small molecule and drug treatment conditioning, and that certain disease conditions may be more effectively paired with specific MSC conditioning strategies to improve their therapeutic effectiveness.

<p>In angle-only target tracking the aim is to estimate the state of a target with use of measurement of elevation and azimuth. The state consists of relative position and velocity between the target and the platform. The platform is an Unmanned Aerial Vehicle (UAV) and the tracking system is meant to be a part of the platform’s anti-collision system. In the case where both the target and the platform travel with constant velocity the angle measurements do not provide any information of the range between the target and the platform. The platform has to maneuver to be able to estimate the range to the target.</p><p>Two filters are implemented and tested on simulated data. The first filter is based on a Extended Kalman Filter (EKF) and is designed for tracking nonmaneuvering targets. Different platform maneuvers are studied and the influence of initial errors and the geometry of the simulation scenario is investigated. The filter is able to estimate the position of the target if the platform maneuvers and the target travels with constant velocity. Maneuvering targets on the other hand can not be tracked by the filter.</p><p>The second filter is an interacting multiple model (IMM) filter, designed for tracking maneuvering targets. The filter performance is highly dependent of the geometry of the scenario. The filter has been tuned for a scenario where the target approaches the platform from the front. In this scenario the filter is able to track both maneuvering and non-maneuvering targets. If the target approaches the platform from the side on the other hand, the filter has problems with distinguish target maneuvers from measurement noise.</p>

In angle-only target tracking the aim is to estimate the state of a target with use of measurement of elevation and azimuth. The state consists of relative position and velocity between the target and the platform. The platform is an Unmanned Aerial Vehicle (UAV) and the tracking system is meant to be a part of the platform’s anti-collision system. In the case where both the target and the platform travel with constant velocity the angle measurements do not provide any information of the range between the target and the platform. The platform has to maneuver to be able to estimate the range to the target. Two filters are implemented and tested on simulated data. The first filter is based on a Extended Kalman Filter (EKF) and is designed for tracking nonmaneuvering targets. Different platform maneuvers are studied and the influence of initial errors and the geometry of the simulation scenario is investigated. The filter is able to estimate the position of the target if the platform maneuvers and the target travels with constant velocity. Maneuvering targets on the other hand can not be tracked by the filter. The second filter is an interacting multiple model (IMM) filter, designed for tracking maneuvering targets. The filter performance is highly dependent of the geometry of the scenario. The filter has been tuned for a scenario where the target approaches the platform from the front. In this scenario the filter is able to track both maneuvering and non-maneuvering targets. If the target approaches the platform from the side on the other hand, the filter has problems with distinguish target maneuvers from measurement noise.

The transformed rejection method uses inversion to sample from the dominating density of a rejection algorithm. But in contrast to the usual method it is enough to know the inverse distribution function F^(-1)(x) of the dominating density. This idea can be applied to various continuous (e.g. normal, Cauchy and exponential) and discrete (e.g. binomial and Poisson) distributions with high acceptance probabilities. The resulting algorithms are short, simple and fast. Even more important is the fact that the quality of the method when used in combination with a linear congruential uniform generator is high compared with the quality of the ratio of uniforms method. In addition transformed rejection can be easily employed for correlation induction. (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing

We discuss queueing systems subject to total disasters. If the time intervals between successive disasters are i.i.d. random variables independent of arrival and service process and arrivals form a Poisson process, then the transient and the asymptotic analysis of such models may be based on Feller's Second Renewal Theorem. Several examples are given: the limiting behavior of M/G/1 in case of exponential disasters and its special cases M/M/1, M/M/1/K and M/M/infinity. (author´s abstract) / Series: Research Report Series / Department of Statistics and Mathematics

We present a new method for the computation of low rank approximations to the solution of large, sparse, stable Lyapunov equations. It is based on a generalization of the classical Smith method and profits by the usual low rank property of the right hand side matrix. The requirements of the method are moderate with respect to both computational cost and memory. Hence, it provides a possibility to tackle large scale control problems. Besides the efficient solution of the matrix equation itself, a thorough integration of the method into several control algorithms can improve their performance to a high degree. This is demonstrated for algorithms for model reduction and optimal control. Furthermore, we propose a heuristic for determining a set of suboptimal ADI shift parameters. This heuristic, which is based on a pair of Arnoldi processes, does not require any a priori knowledge on the spectrum of the coefficient matrix of the Lyapunov equation. Numerical experiments show the efficiency of the iterative scheme combined with the heuristic for the ADI parameters.