93 research outputs found

    Statistical Methods for Classification of Wooden Boards

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    The quality inspection of wooden boards is experiencing a large change. By the use of camera and laser technology board characteristics and defects can be instantly identified and measured. This thesis investigates how the information from a quality inspection system can be used to classify boards into different quality classes, by the use of statistical classification models. Two types of classification models have been tested, Logistic Regression and Support Vector Machines. To deal with potential overfitting a regularized version of Logistic Regression is implemented, and to deal with ordinal dependent variables a logistic regression model for ordinal variables has been implemented. The classification models have been tested against board strength classes, and similar results have been obtained by most models. It is concluded that the regularized logistic regression is the model that manages to classify most boards correctly, but the Support Vector Machine produces a better result on classes where training data is scarce. The thesis was done on behalf of RemaSawco AB, a company that manufactures measurement systems and inspection systems for the sawmill industry

    Secure and scalable deduplication of horizontally partitioned health data for privacy-preserving distributed statistical computation

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    Background Techniques have been developed to compute statistics on distributed datasets without revealing private information except the statistical results. However, duplicate records in a distributed dataset may lead to incorrect statistical results. Therefore, to increase the accuracy of the statistical analysis of a distributed dataset, secure deduplication is an important preprocessing step. Methods We designed a secure protocol for the deduplication of horizontally partitioned datasets with deterministic record linkage algorithms. We provided a formal security analysis of the protocol in the presence of semi-honest adversaries. The protocol was implemented and deployed across three microbiology laboratories located in Norway, and we ran experiments on the datasets in which the number of records for each laboratory varied. Experiments were also performed on simulated microbiology datasets and data custodians connected through a local area network. Results The security analysis demonstrated that the protocol protects the privacy of individuals and data custodians under a semi-honest adversarial model. More precisely, the protocol remains secure with the collusion of up to N − 2 corrupt data custodians. The total runtime for the protocol scales linearly with the addition of data custodians and records. One million simulated records distributed across 20 data custodians were deduplicated within 45 s. The experimental results showed that the protocol is more efficient and scalable than previous protocols for the same problem. Conclusions The proposed deduplication protocol is efficient and scalable for practical uses while protecting the privacy of patients and data custodians

    Development of OLAP with Star Schema

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    Syfte: Att utifrÄn utvalda scenarios identifiera vilka möjliga effekter som anvÀndandet av OLAP kan leda till. Genom en diskussion om nyttan med OLAP, efter att ha presenterat de scenarios som uppkom efter fallstudien, ge lÀsaren en ökad förstÄelse över hur olika brancher kan dra nytta av OLAP i deras respektive omrÄden och visa hur kraftfullt OLAP kan vara för organisationer och verksamheter. ForskningsfrÄga: Vilka möjliga effekter kan OLAP tillföra i en verksamhet? Metod: En kvalitativ metod kallad fallstudie antogs till denna studie dÄ ett antal scenarios arbetades fram. Datainsamlingen skedde med hjÀlp av en kvalitativ metod. Teori: Kapitlet inleds med en förklaring till OLAP och dess komponenter. HÀr förklaras OLAP, datalager, data mining, datakvalité, datalagrets datastruktur, stjÀrnschema, samt snöflingeschema. Resultat: Ett antal scenarios arbetades fram med utgÄngspunkt frÄn existerande verksamheter och samhÀllssektorer. StjÀrnschema, faktatabeller, dataexempel samt avslutningsvis SQL-frÄgor baserade pÄ dessa stjÀrnscheman presenteras i detta avsnitt. Slutsats: Effekterna som OLAP tillförde varierade beroende pÄ vilken branch som OLAP nyttjades i. SÄ lÀnge som verksamheterna utnyttjade sina fördelar sÄ medförde OLAP nytta till respektive verksamhet

    The Nordic Expert Group for Criteria Documentation of Health Risks from Chemicals : 128. Triglycidyl isocyanurate

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    Triglycidyl isocyanurate (TGIC) is a solid, slightly soluble in water. It has a very low vapour pressure, and will therefore occur as dust at the workplace. TGIC is an epoxy compound containing three epoxy groups. Technical TGIC is a mixture of the a : and ß-isomer. TGIC is often used as a hardener. The main use is in the manufacture of polyester powder coatings for metal finishing. The powder coatings usually contain between 4 and 10% TGIC. There is little information found with respect to the toxicokinetics of TGIC. However, some data on a -TGIC indicate that TGIC is rapidly and extensively metabolised. TGIC may cause allergic contact dermatitis in humans. Several cases have been reported subsequent to occupational exposure. However, the contact sensitising potential of TGIC remains to be established. TGIC has been shown to be mutagenic/genotoxic in vitro. Furthermore, there are data that demonstrate a genotoxic potential of TGIC in vivo. A reduction in male fertility and a dose-related decrease in the number of spermatozoa has also been reported in animals. Experimental animal studies indicate that TGIC instilled into the eyes may cause severe eye damage. The major concerns for human health are contact allergy, mutagenicity/genotoxicity and reproductive toxicity. At the present state of knowledge it is not possible to identify a dose or exposure level at which these adverse effects do not occur.Triglycidylisocyanurat (TGIC) Ă€r ett fast Ă€mne, nĂ„got lösligt i vatten. Det har mycket lĂ„gt Ă„ngtryck och förekommer dĂ€rför som damm i arbetsmiljön. TGIC Ă€r en epoxiförening och innehĂ„ller tre epoxigrupper. Tekniskt TGIC Ă€r en blandning av a : och ß-isomeren. TGIC anvĂ€nds ofta som hĂ€rdare, framför allt vid tillverkning av pulverlacker av polyestertyp avsedda för ytbehandling av metall. Pulverlackerna innehĂ„ller vanligen mellan 4 och 10% TGIC. Informationen om upptag och omsĂ€ttning av TGIC Ă€r sparsam, men data gĂ€llande a -TGIC antyder att metabolismen av TGIC Ă€r snabb och omfattande. TGIC kan förorsaka allergiskt kontakteksem hos mĂ€nniska. Åtskilliga fall har rapporterats i samband med yrkesmĂ€ssig exponering, men Ă€mnets kontaktsensibiliserande potential Ă„terstĂ„r att faststĂ€lla. TGIC har visats vara mutagent/genotoxiskt in vitro. Andra data visar att TGIC Ă€r genotoxiskt in vivo. Minskad fertilitet och en dos-relaterad minskning av antalet spermier har ocksĂ„ rapporterats hos handjur. Djurexperimentella studier indikerar att TGIC kan förorsaka svĂ„ra ögonskador vid instillation i ögat. De toxiska effekter som framför allt inger oro vid yrkesmĂ€ssig exponering för TGIC Ă€r kontaktallergi, mutagenicitet/genotoxicitet och reproduktionstoxicitet. Med dagens kunskap Ă€r det inte möjligt att identifiera en dos eller exponeringsnivĂ„ vid vilken dessa effekter inte upptrĂ€der. Nyckelord: Allergiskt kontakteksem, genotoxicitet, grĂ€nsvĂ€rden, mutagenicitet, pulverlacker, reproduktionstoxicitet, riskbedömning, TGIC, toxicitet, triglycidylisocyanurat, ögonskad

    Offshore Outsourcing – Betydande faktorer genom processen

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    En allt högre global konkurrens har tvingat organisationer till omstruktureringar för att effektivisera sina interna processer. Detta har Àven satt sina spÄr pÄ organisationers IT-försörjning vilket medfört att organisationer idag söker nya möjligheter att effektivisera sin försörjning av IT. I detta avseende har offshore outsourcing kommit fram som ett attraktivt alternativ. Det finns dock en stor komplexitet och mÄnga risker förknippad med offshore outsourcing vilket krÀver stor medvetenhet om faktorer som kan pÄverka processen relaterad till denna företeelse. Syftet med denna studie har varit att kartlÀgga betydande faktorer relaterade till offshore outsourcing samt undersöka en möjlig modell för att stödja processen relaterad till fenomenet. Efter en omfattande teoretisk studie och en empirisk fallstudie baserad pÄ sex intervjuer har denna studie lyft fram och beskrivit betydande faktorer relaterade till offshore outsourcingprocessen samt ÄskÄdigtgjort dessa i en vÀgledande modell

    Bringing field theory to social media, and vice-versa : Network-crawling an economy of recognition on Facebook

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    Social media research needs social theory in order to historicize and contextualize findings. At the same time, (analogue) social theory may benefit from the affordances of digital methods. This article explores this Janus-faced argument by way of a Facebook crawl of the Swedish field of culture. First, it is argued that field theory helps understand inter-institutional interaction on social media, and that it places activities on social media in a broader social context. Findings of the Facebook crawl illustrate the persistence of the structure and autonomy of the field of culture as depicted by Bourdieu. Second, despite Bourdieu’s rejection of network analysis, it is argued that it supplements empirical field research on two counts. Bourdieu argued for a relational understanding of the social world and for the study of “objective relations” between agents in a field. Following this, the network analysis provides a focus on actual practices—crystallized acts of recognition in the form of “likes” between institutions. This contrasts the somewhat oxymoronic use of self-reports to study “objective relations” that to date characterize Bourdieusian sociology. Additionally, the network analysis of a crawl of institutions on social media has the capacity to begin to uncover the amplitude, or reach, of a social field—which to date is rare in empirical field research. The article concludes by arguing for the mutual benefit of social theory and digital methods

    Establishment versus Newcomers, Critical versus Administrative? : Sketching the structure of the Swedish field of media and communication studies

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    The status of the field of media and communication studies has been debated globally and domestically. This study covers virtually all agents (N=254) in the Swedish field of media and communication studies and draws on Pierre Bourdieu's sociology of science to uncover the main hierarchies in the field. The study focuses on two main divisions. Like in most fields, the most prevalent division is found between the field's incumbents and the challengers/newcomers. A parallel, albeit less prevalent, division is an ontoepistemological one - a variant of the old cleavage between "critical" and "administrative" research. The field's power elite is almost exclusively male, and connected to the field's pioneering institutions

    Symbolic violence and the social space : Self-imposing the mark of disgrace?

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    A great amount of effort has gone into studying correspondences between contemporary class structures and the distribution of lifestyles and media practices therein. Structural overlaps between these spaces imply the existence of a symbolic order, where dominant factions of society constitute taste keepers endowed with the power to stigmatize those below them in the social hierarchy. Yet, research has not come to terms with the reach and depth of this symbolic order. This study combines the Bourdieusian approach with recent developments in stigma research and the notion of felt stigma. Using multiple correspondence analysis on a survey with the adult Swedish population (n = 2003) findings align with previous research in that the social space is built around capital volume and capital composition, and that media practices connect to that structure. This symbolic order is not, however, internalized by people at lower social positions. Instead, it is people invested in culture and arts – a cultural middle-class – who are most likely to anticipate that others would look down on their practices and preferences

    The City as Spectacle : A Debordian Critique of the City as Commodity and Brand

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    In this paper focus is put on how the ”meta-processes” (Krotz, 2007) of mediatization and commercialization are expressed in relation to the city – how they conflate and create the conditions from which the being of the contemporary city is renegotiated from polis to postpolis. The contemporary “commodification of everything” (Harvey, 2005) and the logic of the global market economy means that the city expresses a need to create a “competitive identity” (Anholt, 2007) and elevate to the fore of attention its’ “collective symbolic capital” (Harvey, 2012). This involves turning the city into a brand and as such, the city becomes dependent upon the logics of the media and the symbol – the contemporary city is “the realm of the sign” (Tesfahuney & Schough, 2009: 142). In all its shapes, suggests Debord, “the society of the spectacle constitutes the model for the dominant perspective in society” (2002: 22). Thus the representation of the city – the city-as-a-brand - is both ideological and political in the sense that makes claims as to “represent the entirety of the city when the image is actually a strongly selective and partial ideal image” (Ek, 2007: 97). But the city-as-a-brand is also political in its attempts at reifying the city as a non-political entity. The spectacle-city – the city which turned in to a commodity which turned into a brand which lost itself in its own appealing mirror image like Narcissus - embodies an extreme commodity fetishism in the way in which its’ social relations (criminality, segregation, unemployment, gentrification) are placed in the shadows. The resources spent on city-branding amplifies the image of the city as the “space of ultimate experiences” (Tesfahuney & Schough, 2009: 120) while the consequences of neoliberal doctrine veils itself behind the curtains.
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