Towards Psychometrics-based Friend Recommendations in Social Networking Services

Two of the defining elements of Social Networking Services are the social profile, containing information about the user, and the social graph, containing information about the connections between users. Social Networking Services are used to connect to known people as well as to discover new contacts. Current friend recommendation mechanisms typically utilize the social graph. In this paper, we argue that psychometrics, the field of measuring personality traits, can help make meaningful friend recommendations based on an extended social profile containing collected smartphone sensor data. This will support the development of highly distributed Social Networking Services without central knowledge of the social graph.Comment: Accepted for publication at the 2017 International Conference on AI & Mobile Services (IEEE AIMS

Microalgae as substrates for fermentative biogas production in a combined biorefinery concept

Mussgnug JH, Klassen V, Schlüter A, Kruse O. Microalgae as substrates for fermentative biogas production in a combined biorefinery concept. Journal of Biotechnology. 2010;150(1):51-56.Most organic matter can be used for bioenergy generation via anaerobic fermentation. Today, crop plants like maize play the dominant role as substrates for renewable biogas production. In this work we investigated the suitability of six dominant microalgae species (freshwater and saltwater algae and cyanobacteria) as alternative substrates for biogas production. We could demonstrate that the biogas potential is strongly dependent on the species and on the pretreatment. Fermentation of the green alga Chlamydomonas reinhardtii was efficient with a production of 587 ml (+/- 8.8 SE) biogas g volatile solids(-1) (VS-1), whereas fermentation of Scenedesmus obliquus was inefficient with only 287 ml (+/- 10.1 SE) biogas g VS-1 being produced. Drying as a pretreatment decreased the amount of biogas production to ca. 80%. The methane content of biogas from microalgae was 7-13% higher compared to biogas from maize silage. To evaluate integrative biorefinery concepts, hydrogen production in C. reinhardtii prior to anaerobic fermentation of the algae biomass was measured and resulted in an increase of biogas generation to 123% (+/- 3.7 SE). We conclude that selected algae species can be good substrates for biogas production and that anaerobic fermentation can seriously be considered as final step in future microalgae-based biorefinery concepts. (C) 2010 Elsevier B.V. All rights reserved

Efficiency and biotechnological aspects of biogas production from microalgal substrates

Klassen V, Blifernez-Klassen O, Wobbe L, Schlüter A, Kruse O, Mussgnug JH. Efficiency and biotechnological aspects of biogas production from microalgal substrates. Journal of Biotechnology. 2016;234:7-26.Photosynthetic organisms like plants and algae can harvest, convert, and store solar energy and thus represent readily available sources for renewable biofuels production on a domestic or industrial scale. Anaerobic digestion (AD) of the organic biomass yields biogas, containing methane and carbon dioxide as major constituents. Combustion of the biogas or purification of the energy-rich methane fraction can be applied to provide electricity or fuel. AD procedures have been applied for several decades with organic waste, animal products, or higher plants and more recently, utilization of photosynthetic algae as substrates has gained considerable research interest. To provide an overview of recent research efforts made to characterize the AD process of microalgal biomass, we present extended summaries of experimentally determined biochemical methane potentials (BMP), biomass pretreatment options and digestion strategies in this article. We conclude that cultivation options, biomass composition and time of harvesting, application of biomass pretreatment strategies, and parameters of the digestion process are all important factors, which can significantly affect the AD process efficiency. The transition from batch to continuous microalgal biomass digestion trials, accompanied by state-of-the-art analytical techniques, is now in demand to refine the assessments of the overall process feasibility

The track finding algorithm of the Belle II vertex detectors

The Belle II experiment is a high energy multi purpose particle detector operated at the asymmetric e+e− - collider SuperKEKB in Tsukuba (Japan). In this work we describe the algorithm performing the pattern recognition for inner tracking detector which consists of two layers of pixel detectors and four layers of double sided silicon strip detectors arranged around the interaction region. The track finding algorithm will be used both during the High Level Trigger on-line track reconstruction and during the off-line full reconstruction. It must provide good efficiency down to momenta as low as 50 MeV/c where material effects are sizeable even in an extremely thin detector as the VXD. In addition it has to be able to cope with the high occupancy of the Belle II detectors due to the background. The underlying concept of the track finding algorithm, as well as details of the implementation are outlined. The algorithm is proven to run with good performance on simulated ϒ(4S) → BB̄ events with an efficiency for reconstructing tracks of above 90% over a wide range of momentum