Open Source og søketeknologi for virksomheter

Fri programvare og søk i virksomheter blir stadig viktigere. Lukket og åpen programvare står på hver sin kant. De førstnevnte regjerer i det øvre markedssjiktet. Allikevel er det skrevet og gjort lite for å undersøke hvordan fri programvare kan løse problemet. Det finnes ingen komplett, åpen plattform for virksomhetssøk. Er det mulig å lage det? Det viser seg at svaret i mange tilfeller vil være “ja”, men det må tas en rekke forbehold. Det er vanskelig å lage et produkt uten noen klar målgruppe. Målgruppen “virksomheter” er i mange tilfeller ikke konkret nok. De store virksomhetene vil uansett legge den største innsatsen i tilpassing, og da er det lite hensiktsmessig at utgangspunktet deres er altfor spesifikt. Videre ligger ikke de høyeste kostnadene for de store virksomhetene i selve produktene, men i tilpassingen. Oppgaven diskuterer hvordan Apache Lucene, Nutch, Solr og andre har et potensiale til å utvikle seg til grunnlaget for en fremtidig søkeplattform for virksomheter, basert kun på fri programvare

Epstein-Barr virus and malaria upregulate AID and APOBEC3 enzymes, but only AID seems to play a major mutagenic role in Burkitt lymphoma

Endemic Burkitt lymphoma (eBL) is characterized by an oncogenic IGH/c-MYC translocation and Epstein-Barr virus (EBV) positivity, and is epidemiologically linked to Plasmodium falciparum malaria. Both EBV and malaria are thought to contribute to eBL by inducing the expression of activation-induced cytidine deaminase (AID), an enzyme involved in the IGH/c-MYC translocation. AID/apolipoprotein B mRNA editing catalytic polypeptide-like (AID/APOBEC) family enzymes have recently emerged as potent mutagenic sources in a variety of cancers, but apart from AID, their involvement in eBL and their regulation by EBV and P. falciparum is unknown. Here, we show that upon inoculation with EBV, human B cells strongly upregulate the expression of enzymatically active APOBEC3B and APOBEC3G. In addition, we found significantly increased levels of APOBEC3A in B cells of malaria patients, which correlated with parasite load. Interestingly, despite the fact that APOBEC3A, APOBEC3B, and APOBEC3G caused c-MYC mutations when overexpressed in HEK293T cells, a mutational enrichment in eBL tumors was only detected in AID motifs. This suggests that even though the EBV- and P. falciparum-directed immune response triggers the expression and activity of several AID/APOBEC members, only the upregulation of AID has oncogenic consequences, while the induction of the APOBEC3 subfamily may primarily have immunoprotective functions

Adaptive Resonant Controllers in a Modular Multilevel Converter - An Analytical Study of the Circulating Current Suppressing Controller

In this thesis work, the modular multilevel converter was investigated. More specifically, an analytical study of circulating current suppression methods for low-bandwidth systems was undertaken. A comparative study of two frequency adaptive digital controllers proposed in earlier research papers has been evaluated to check which yields the most efficient controller. The modular multilevel converter (MMC) is a converter aimed for high voltage direct current applications. Compared to other voltage source converters, the MMC has several distinct advantages; high efficiency, scalability, modularity, and superior harmonic performance. One of the key advantages is its modular design. The redundancy is proportional to the number of submodules, and having multiple submodules in series gives high redundancy. If one submodule were to fail, the converter could continue to operate with high efficiency by bypassing the failed sub-module. However, its modular design does also have some drawbacks. First, the more submodules, the higher switching losses. However, the switching losses can be reduced by lowering the switching frequency. By reducing the switching frequency, the system s bandwidth reduces as well. Consequently, the controller s ability to suppress disturbances reduces. Second, a circulating current is introduced to the system. The circulating current is responsible for transferring power from the dc-link to the ac-side, and also balance the energy of the capacitors. If not controlled, the circulating current will be predominant of a second harmonic, which results in higher resistive losses. The additional resistive losses affect the lifetime of semiconductor devices and passive components due to the temperature rise. To suppress the second harmonic during grid frequency fluctuations, studies of a digital frequency adaptive controller was undertaken. A proportional resonant controller was digitally realised in an infinite impulse response (IIR) filter. By only changing one variable, the filter adapts its resonant peak according to the measured grid frequency. A phase-locked loop was used in combination with a look-up table to measure the grid frequency and to give a new parameter for the IIR filter. A comparative study of two frequency adaptive digital PR controllers has been undertaken. Both methods are used to change the resonant peak of the IIR filter. The first method proposed in [1] focuses on changing ω0, while the second method proposed in [2] focuses on changing the sampling time. Both controllers were simulated in a system where the grid frequency changed from 50 Hz to 52 Hz, resulting in a 4 Hz jump in the second harmonic. A fast Fourier transform (FFT) analysis reveals that both methods work with high efficiency. However, in medium- and low-bandwidth systems the method proposed in [1] was able to suppress the second harmonic more effectively

Mood, anxiety, and alcohol use disorders and later cause-specific sick leave in young adult employees

Background Mental disorders strongly influence work capability in young adults, but it is not clear which disorders that are most strongly associated with sick leave, and which diagnoses that are stated on the sick leave certificates. Better knowledge of the impairments associated with different mental disorders is needed for optimal planning of interventions and prioritization of health services. In the current study, we investigate the prospective associations between eight mood, anxiety, and alcohol use disorders, and later sick leave granted for mental, somatic, or any disorder. Methods Lifetime mental disorders were assessed by structured diagnostic interviews in 2,178 young adults followed for eight years with registry data on sick leave. Relative risk ratios were estimated for the associations between each mental disorder and the different forms of sick leave. Results All included diagnoses were associated with later sick leave. In adjusted analyses, major depressive disorder and generalized anxiety disorder were the strongest predictors of sick leave granted for mental disorders, whereas social anxiety disorder and specific phobia were the strongest predictors of sick leave granted for somatic disorders. Specific phobia and major depressive disorder had the highest attributable fractions for all-cause sick leave. Conclusions Mood and anxiety disorders constituted independent risk factors for all cause sick leave, whereas alcohol use disorders seemed to be of less importance in young adulthood. Disorders characterised by distress were most strongly associated with sick leave granted for mental disorders, whereas disorders characterised by fear primarily predicted sick leave granted for somatic conditions. A large part of all sick leave is related to specific phobia, due to the high prevalence of this disorder. The impairment associated with this common disorder may be under-acknowledged, and it could decrease work capacity among individuals with somatic disorders. This disorder has good treatment response and may be overlooked as a target for interventions aimed at prevention of sick leave