Modeling and Prediction of Radio Channels for Orthogonal Frequency Division Multiplexing

In a wireless communication system, the channel is ever changing due to multipath properties such as excess delays and constructive and destructive interference. In a step to optimize system performance, it would be beneficial to have access to channel state information of both present subchannels' future development and subchannels outside the currently used frequency interval. In this thesis, radio channels for Orthogonal Frequency Division Multiplexing (OFDM) is concerned. Channels are modelled and a prediction algorithm appli-cable in time or frequency direction of the frequency response is developed. The algorithm derives an autoregressive (AR) model of the channel and exploits the close connection between prediction of a time discrete signal and an autoregres-sive process. The great over sampling at the receiver, compared to the maximum Doppler shift or maximum excess delay of the channel, yields it feasible to derive the model with decreased sampling rate and thus only use pilot symbols. This rate reduction gives longer accurate predictions but also an interpolation issue that is solved by Wiener filters. The mean performance of the approach is evaluated by calculating the root mean square error (RMSE) of predictions as functions of various channel and algorithm parameters. Simulations show that the algorithm is able to predict several coherence times or coherence bandwidths of a channel. The algorithm is also extended to use several OFDM symbols and an averaging finite impulse response (FIR) filter, yielding a considerable increase in prediction performance. It is also appraised as a tool for adaptive symbol mapping in a frequency interval not currently used. Results show an opportunity of substantially higher data throughput than for a mapping scheme based on the mean SNR of the channel

Construction and Control of an Educational Lab Process - The Gantry Crane

In this paper, we describe the construction and control of a gantry crane that is used in courses at the Department of Automatic Control, Lund university. Two different models of the crane are developed. A thorough example of path following, including on-line time-varying input/state-transformations and LQG control, used in a laboratory exercise is shown together with experimental results. Time-optimal trajectories for position control, with constraints on positions, load angles, and control signals are computed using Modelica and Optimica

Relations Between Control Signal Properties and Robustness Measures

In this paper we consider control signal properties, such as maximum magnitude and activity, as well as system robustness measures. We derive an ideal controller and control signal for exponential disturbance rejection for a first order process with time delay. For the resulting closed-loop system, it is shown analytically that there are strong interconnections between robustness measures and control signal properties regarding load disturbance attenuation. The results imply that popular controller design methods implicitly take control signal properties into consideration

Rapid Manufacturing with Electron Beam Melting (EBM) - A Manufacturing Revolution?

The Electron Beam Melting technology is the result of intensive research and development and has a wide array of applications within areas such as Rapid Prototyping, Rapid Manufacturing, Tooling and Biomedical Engineering. The technology combines first-class material properties with high build speeds. The presentation will provide a basic understanding of the technology, technical status, applications and ongoing R&D.Mechanical Engineerin

The expression signature of in vitro senescence resembles mouse but not human aging

BACKGROUND: The biological mechanisms that underlie aging have not yet been fully identified. Senescence, a phenomenon occurring in vitro, limits the number of cell divisions in mammalian cell cultures and has been suggested to contribute to aging. RESULTS: We investigated whether the changes in gene expression that occur during mammalian aging and induction of cellular senescence are similar. We compared changes of gene expression in seven microarray datasets from aging human, mouse and rat, as well as four microarray datasets from senescent cells of man and mouse. The datasets were publicly available or obtained from other laboratories. Correlation measures were used to establish similarities of the expression profiles and gene ontology analyses to identify functional groups of genes that are co-regulated. Robust similarities were established between aging in different species and tissues, indicating that there is an aging transcriptome. Although some cross-species comparisons displayed high correlation, intra-species similarities were more reliable. Similarly, a senescence transcriptome was demonstrated that is conserved across cell types. A similarity between the expression signatures of cellular senescence and aging could be established in mouse, but not in human. CONCLUSION: Our study is the first to use microarray data from several studies and laboratories for dissection of a complex biological phenotype. We demonstrate the presence of a mammalian aging transcriptome, and discuss why similarity between cellular senescence and aging is apparent in aging mice only

Promoting an image of independence: An institutional perspective on nonprofit organizational strategies

This article focuses on how the alleged value of independence in nonprofit organizations should be conceptualized, researched, and advanced. Through the conceptualization of independence as an institutional norm, the article makes several contributions to research on strategies for independence in nonprofit organizations. Rather than focusing on independence as a tangible organizational quality, the article studies and analyzes overarching strategies with which nonprofit organizations promote an image of independence. Recategorizations of results from previous research and illustrations from case studies of Swedish nonprofit ecolabeling serve as the main empirical material. By conceptualizing how nonprofit organizations employ multiple, and sometimes even contradictory, organizational strategies for being perceived as independent, the scope of research is broadened and the roles of institutional contexts and processes are highlighted

Soffliggare för ett bättre samhälle? En studie om att skapa socialt kapital

Social capital is the key to an effective and well functioning liberal democracy according to Robert D. Putnam in the theory about Making democracy work, and Bo Rothstein in the theory about the Logic of the social trap. The solution to create social capital is according to Putnam a high level of participation in civic communities in the civic society and according to Rothstein the need of universal and equal political institutions. Couchsurfing is a social network and a community for sharing couches with others while traveling. This thesis addresses the question if Couchsurfing is able to produce social capital, and if so affect the society in a positive way. With a qualitative approach to the question, the collected material I'm looking for to analyze is extracted from interviews by members within the Couchsurfing community. The material is analyzed according to categories developed from the theories. The result and answer to the addressed question is that Couchsurfing possesses many of the qualities described in the theories. According to that is Couchsurfing a network that is creating social capital, and then also according to the theories able influence the society it operates in

Considerations when using the significance analysis of microarrays (SAM) algorithm

BACKGROUND: Users of microarray technology typically strive to use universally acceptable data analysis strategies to determine significant expression changes in their experiments. One of the most frequently utilised methods for gene expression data analysis is SAM (significance analysis of microarrays). The impact of selection thresholds, on the output from SAM, may critically alter the conclusion of a study, yet this consideration has not been systematically evaluated in any publication. RESULTS: We have examined the effect of discrete data selection criteria (qualification criteria for inclusion) and response thresholds (out-put filtering) on the number of significant genes reported by SAM. The use of a reduced data set by applying arbitrary restrictions vis-à-vis abundance calls (e.g. from D-chip) or application of the fold change (FC) option within SAM (named the FC hurdle hereafter), can substantially alter the significant gene list when running SAM in Microsoft Excel. We determined that for a given final FC criteria (e.g. 1.5 fold change) the FC hurdle applied within Microsoft Excel SAM alters the number of reported genes above the final FC criteria. The reason is that the FC hurdle changes the composition of the control data set, such that a different significance level (q-value) is obtained for any given gene. This effect can be so large that it changes subsequent post hoc analysis interpretation, such as ontology overrepresentation analysis. CONCLUSION: Our results argue for caution when using SAM. All data sets analysed with SAM could be reanalysed taking into account the potential impact of the use of arbitrary thresholds to trim data sets before significance testing

Staten och det civila samhället. Idétraditioner och tankemodeller i den statliga bidragsgivningen till ideella organisationer

Idéburna eller ideella organisationer som formellt står utanför såväl statsapparat som näringsliv finns idag inom alla delar av det svenska samhället. Vi återfinner dem inom allt från rikets styrning och försvar till områden som religion, kultur och fritid men även i vården och omsorgen. Inom de flesta områden (förutom till exempel idrotten och den omfattande folkbildningen) utgör organisationerna en relativt liten del av den totala verksamheten. Tagna samman till en ideell sektor representerar de däremot en viktig resurs och speciell organisatorisk domän i det svenska samhället. I denna typ av organisationer skapas utrymme för andra synsätt och alternativa praktiker. Vidare kanaliserar de en betydande del av det ideella engagemanget, både i form av gåvor och medlemsavgifter och det ideella arbete som utförs varje år. Trots denna betydelse i samhället är vår kunskap idag fortfarande förvånansvärt begränsad när det gäller organisationerna, deras verksamheter och de betingelser de verkar under. Några av de allra viktigaste aktörerna när det gäller organisationernas verksamhet och möjligheter att verka är den svenska statsapparaten och dess myndigheter. De olika former av statliga och kommunala bidrag och ersättningar som idag går till de ideella och idéburna organisationerna överstiger gott och väl tio miljarder kronor årligen. Det handlar möjligen om så mycket som det dubbla värdet. Vidare spelar olika former av indirekta subventioner och skattelättnader stor roll för många organisationer. Trots det vet vi för det första inte särskilt mycket om hur dessa system är utformade eller vilka effekter de har på organisationerna. För det andra antyder tidigare studier att det inte finns någon samlad politik eller övergripande strategi från statens sida när det gäller det civila samhället och dess organisationer i sin helhet. Vi kan i denna rapport i stora drag bekräfta dessa tidigare analyser av den statliga bidragsgivningen. Det finns idag på en övergripande nivå inte någon medveten eller sammanhållen strategi för den samlade statliga bidragsgivningen till ideella eller idéburna organisationer. Detsamma gäller för övriga offentliga ekonomiska system som riktar sig till eller påverkar dessa organisationer. Detta har vi har valt att illustrera med en relativt komplex, men schematisk, skiss över situationen som den ser ut utifrån organisationernas horisont (kapitel 1). I studien visar vi att det inom vissa, i ekonomiska termer, mer omfattande delfält kan existera något av en mer medveten och genomtänkt hållning gentemot organisationerna. Det gäller till exempel de frivilliga försvarsorganisationerna respektive de enskilda biståndsorganisationerna (kapitel 5). Även inom dessa relativt väl sammanhållna områden tycks det dock som om det kan förekomma bidrag och ersättningar och därtill kopplade styrsystem som innehåller tankegods ur flera av de idétraditioner vi har identifierat i denna studie (kapitel 2-4). För denna rapport har vi alltså valt att ställa oss delvis utanför statsapparatens perspektiv. Vid ett par tillfällen har vi istället medvetet valt att använda oss av ett de ideella organisationernas perspektiv. Hittills har effekterna inte undersökts på ett mer systematiskt sätt när det gäller den påverkan statsapparatens system har på organisationerna. Detta är också något som till exempel Tommy Lundström vid Socialhögskolan i Stockholm uppmärksammar när det gäller effekterna på organisationerna av de senaste inslagen i New Public Management-traditionen (Lundström 2004). Han skriver där bland annat: ”Det är värt att understryka att trots en del forskning vet vi mycket litet om kontraktskulturens effekter på de socialt inriktade frivilligorganisationerna. Det gäller hur denna kultur påverkat såväl det organisatoriska landskapet som organisationernas inre liv, inklusive medlemmarnas aktiviteter.” (s. 49) Organisationernas perspektiv är därför en viktig utgångspunkt för vår analys. Detta eftersom de samlade svenska kunskaperna inom området idag fortsatt är mycket fragmentariska och endast svagt sammanhållna. Se dock till exempel (Lundström och Wijkström 1995; Olsson 1998; Olsson 2000; Johansson 2001; Söderholm och Wijkström 2001; Wijkström och Lundström 2002; Johansson 2003). Samtidigt menar vi att det är viktigt att understryka att huvudansvaret för organisationernas organisering, ledning, styrning och ekonomi vilar på de ideella organisationerna själva. Det finns ibland en tendens att lägga ansvaret för organisationernas utveckling på statliga eller kommunala bidragsgivare och bidragssystem, vilket vi menar är ett skevt perspektiv. På samma gång är det värt att notera att de statliga styr- och kontrollsystem som kopplats till olika bidrag och ersättningar är av stor vikt för många organisationer. Vi kan i våra analyser därför inte heller helt bortse ifrån effekterna på organisationerna (se speciellt kapitel 7).civil society; government subsidies; national budget; popular movement; foundations; Sweden; nonprofit; voluntary

KubeNow: A Cloud Agnostic Platform for Microservice-Oriented Applications

KubeNow is a platform for rapid and continuous deployment of microservice-based applications over cloud infrastructure. Within the field of software engineering, the microservice-based architecture is a methodology in which complex applications are divided into smaller, more narrow services. These services are independently deployable and compatible with each other like building blocks. These blocks can be combined in multiple ways, according to specific use cases. Microservices are designed around a few concepts: they offer a minimal and complete set of features, they are portable and platform independent, they are accessible through language agnostic APIs and they are encouraged to use standard data formats. These characteristics promote separation of concerns, isolation and interoperability, while coupling nicely with test-driven development. Among many others, some well-known companies that build their software around microservices are: Google, Amazon, PayPal Holdings Inc. and Netflix [11]