94 research outputs found
Statistical Methods for Classification of Wooden Boards
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
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 Nâââ2 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
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
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 Ă-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 Ă-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. Ă
tskilliga fall har rapporterats i samband med yrkesmÀssig exponering, men Àmnets kontaktsensibiliserande potential ÄterstÄr att faststÀlla. TGIC har visats vara mutagent/genotoxiskt in vitro. Andra data visar att TGIC Àr genotoxiskt in vivo. Minskad fertilitet och en dos-relaterad minskning av antalet spermier har ocksÄ rapporterats hos handjur. Djurexperimentella studier indikerar att TGIC kan förorsaka svÄra ögonskador vid instillation i ögat. De toxiska effekter som framför allt inger oro vid yrkesmÀssig exponering för TGIC Àr kontaktallergi, mutagenicitet/genotoxicitet och reproduktionstoxicitet. Med dagens kunskap Àr det inte möjligt att identifiera en dos eller exponeringsnivÄ vid vilken dessa effekter inte upptrÀder. Nyckelord: Allergiskt kontakteksem, genotoxicitet, grÀnsvÀrden, mutagenicitet, pulverlacker, reproduktionstoxicitet, riskbedömning, TGIC, toxicitet, triglycidylisocyanurat, ögonskad
Offshore Outsourcing â Betydande faktorer genom processen
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
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 Bourdieuâs 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 âobjective relationsâ between agents in a field. Following this, the network analysis provides a focus on actual practicesâcrystallized acts of recognition in the form of âlikesâ between institutions. This contrasts the somewhat oxymoronic use of self-reports to study âobjective relationsâ 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 fieldâwhich 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
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
Smaken för nyheter : Klasskillnader i det digitala medielandskapet
Det Ă€r jobbigt att prata om klass. Men faktum Ă€r att Sverige Ă€r ett klassamhĂ€lle dĂ€r mĂ€nniskor med olika tillgĂ„ng till ekonomiskt och kulturellt kapital konkurrerar om posiÂtioner, inflytande och status. Vi lever i ett samhĂ€lle dĂ€r klass ger upphov till specifika livsstilar och kompasser. Smaken för nyheter utforskar relationen mellan klass och mĂ€nniskors val och vĂ€rderingar i det samtida nyhetslandskapet. I kontrast till den gĂ€ngse bilden â att nyheter utgör en kollektiv nytta som hĂ„ller ihop samhĂ€llet â visar boken att mĂ€nniskor Ă€r olika rustade för att navigera bland nyheter. Tillsammans med kĂ€nslan av att vara allmĂ€nbildad och delaktig i samhĂ€lleliga angelĂ€genheter har nyhetskonsumtion gĂ„tt frĂ„n att fungera som kollektiv nytta till att bli en individuell resurs. FrĂ„gan om nyhetskonsumtion har blivit en klassfrĂ„ga. Detta medför att vi stĂ„r inför en brĂ€nnande demokratisk utmaning. NĂ€r mĂ€nniskor som delar levnadsförhĂ„llanden och nyhetsvĂ€rldar distanserar sig frĂ„n andra grupper, deras livsstilar och preferenser, Ă€r risken nĂ€mligen stor att samhĂ€llsklyftorna fortsĂ€tter att vĂ€xa. Snarare Ă€n att förena blir nyheter nĂ„got som drar isĂ€r
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