Generating realistic scaled complex networks

Research on generative models is a central project in the emerging field of network science, and it studies how statistical patterns found in real networks could be generated by formal rules. Output from these generative models is then the basis for designing and evaluating computational methods on networks, and for verification and simulation studies. During the last two decades, a variety of models has been proposed with an ultimate goal of achieving comprehensive realism for the generated networks. In this study, we (a) introduce a new generator, termed ReCoN; (b) explore how ReCoN and some existing models can be fitted to an original network to produce a structurally similar replica, (c) use ReCoN to produce networks much larger than the original exemplar, and finally (d) discuss open problems and promising research directions. In a comparative experimental study, we find that ReCoN is often superior to many other state-of-the-art network generation methods. We argue that ReCoN is a scalable and effective tool for modeling a given network while preserving important properties at both micro- and macroscopic scales, and for scaling the exemplar data by orders of magnitude in size.Comment: 26 pages, 13 figures, extended version, a preliminary version of the paper was presented at the 5th International Workshop on Complex Networks and their Application

Simulation and design of folded perovskite x-ray detectors

A variety of medical, industrial, and scientific applications requires highly sensitive and cost-effective x-ray detectors for photon energies ranging from keV to MeV. Adapting the thickness of polycrystalline or single crystal conversion layers especially to high-energy applications increases the complexity of fabrication and potentially decreases the performance of conventional direct conversion x-ray detectors. To tackle the challenges with respect to the active layer thickness and to combine the superior performance of single crystal materials with the low-cost nature of polycrystalline conversion layers, we investigate thin film x-ray detector technologies based on a folded device architecture. Analytical models simulating the sensitivity and the detective quantum efficiency (DQE) are used to evaluate the performance of folded detectors based on polycrystalline organic-inorganic perovskite semiconductors in various layout configurations and for different photon energies. Simulations of folded perovskite devices show high sensitivities. The DQE analysis introduces additional noise related boundary conditions for the folding length. A comparison with conventional detectors based on state of the art conversion materials at different photon energies demonstrates the potential of the folded detector layout as simulated sensitivities are comparable to single crystal detectors

Damage stability requirements for passenger ships : collision risk based cost benefit assessment

Currently built passenger ships have to comply with SOLAS 2009 probabilistic damage stability requirements. There are, however, serious concerns regarding the sufficiency of these requirements with respect to the Required Subdivision Index R, which should properly account for the risk of People On Board (POB) and ship’s inherent survivability in case of loss of her watertight integrity. In recent years extensive research on determining the appropriate level of R using risk-based methods has been carried out. The urgency of the matter was reinforced by the quite recent Costa Concordia (2012) accident, even though this accident was not related to a collision event. This paper outlines the objectives, the methodology of work and first results of the ongoing studies funded by EMSA (EMSA III project) focusing on risk-based damage stability requirements for passenger ships. In compliance with IMO Formal Safety Assessment process a collision risk model is further developed based on the results of EU GOALDS project and a new required index shall be suggested by means of cost-benefit assessment. The updated collision risk model uses information from the most recent analysis of casualty reports of databases considering the period 1990 to 201

Analyse der Berücksichtigung eines Wanderungsindikators im Rahmen der Abgrenzung des GRW-Fördergebiets : Gutachten für die Gemeinschaftsaufgabe "Verbesserung der regionalen Wirtschaftsstruktur" im Auftrag des Hessischen Ministeriums für Wirtschaft, Verkehr und Landesentwicklung

"The Joint Task 'Improvement of the Regional Economic Structure' delimits the German promotion areas. For this purpose different indicators reflecting the labor market situation and regional income are linked. So far, no indicator is considered that indicates the demographic change of regions. The Institute for Employment Research was commissioned to produce an expert report on the question if inclusion of a migration indicator could give further information about demographic and other aspects concerning the regional labor market situation. This paper presents the results of the analysis which was financed by the Ministry of economics, transport, urban and regional development of the State of Hesse. We examine the effects of additionally considering migration to determine the contour of the assisted area theoretically as well as in a simulation model. There is some evidence that the inclusion of a migration indicator in the comprehensive model leads to some additional information on regional problems." (Author's abstract, IAB-Doku) ((en))Gemeinschaftsaufgabe Regionale Wirtschaftsförderung, Fördergebiet, Wanderung - Indikatoren, strukturschwache Räume, Arbeitsmarktregion, Binnenwanderung, Indikatorenbildung

Polymorphisms within the canine MLPH gene are associated with dilute coat color in dogs

BACKGROUND: Pinschers and other dogs with coat color dilution show a characteristic pigmentation phenotype. The fur colors are a lighter shade, e.g. silvery grey (blue) instead of black and a sandy color (Isabella fawn) instead of red or brown. In some dogs the coat color dilution is sometimes accompanied by hair loss and recurrent skin inflammation, the so called color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD). In humans and mice a comparable pigmentation phenotype without any documented hair loss is caused by mutations within the melanophilin gene (MLPH). RESULTS: We sequenced the canine MLPH gene and performed a mutation analysis of the MLPH exons in 6 Doberman Pinschers and 5 German Pinschers. A total of 48 sequence variations was identified within and between the breeds. Three families of dogs showed co-segregation for at least one polymorphism in an MLPH exon and the dilute phenotype. No single polymorphism was identified in the coding sequences or at splice sites that is likely to be causative for the dilute phenotype of all dogs examined. In 18 German Pinschers a mutation in exon 7 (R199H) was consistently associated with the dilute phenotype. However, as this mutation was present in homozygous state in four dogs of other breeds with wildtype pigmentation, it seems unlikely that this mutation is truly causative for coat color dilution. In Doberman Pinschers as well as in Large Munsterlanders with BHFD, a set of single nucleotide polymorphisms (SNPs) around exon 2 was identified that show a highly significant association to the dilute phenotype. CONCLUSION: This study provides evidence that coat color dilution is caused by one or more mutations within or near the MLPH gene in several dog breeds. The data on polymorphisms that are strongly associated with the dilute phenotype will allow the genetic testing of Pinschers to facilitate the breeding of dogs with defined coat colors and to select against Large Munsterlanders carrying BHFD

GoOrganic - ökologisches Zuchtprogramm für Milchziegen

Im vorliegenden Projekt soll modellhaft ein ökologisches Zuchtprogramm für Milchziegen entwickelt werden. Zuchtziel ist eine hohe Milchlebensleistung bei guten Inhaltsstoffen und Robustheit. Hierfür müssen geeignete Merkmale abgeleitet und in die Leistungsprüfung integriert werden. Zudem ist die aktive Einbindung der Ziegenzüchter in die Durchführung des Zuchtprogramms ein wichtiges Element. Es wurden verschiedene Einflussfaktoren auf die Milchlebensleistung untersucht. Von besonderem Interesse ist, in wie weit auf der Basis der ersten 120-Tage-Leistung eine Aussage zu den Lebensleistungsmerkmalen getroffen werden kann. Flankierend wurde ein Diagnosecode für ein Gesundheits- und Robustheitsmonitoring erstellt. Zur partizipativen Weiterentwicklung des Zuchtprogramms wurden Schulungen und Workshops durchgeführt. Zudem soll die Datenbank ZDV so ausgebaut werden, dass sie Berater und Züchter in der aktiven Zuchtarbeit unterstützt

Zuchtprogramme ohne Biotechnologie - Etablierung von Bockringen in der Ziegenzüchtung

Within organic livestock farming, the use of AI versus natural mating is under steady discussion. However, no special organic breeding programs without AI are set in place so far. The present study takes goat breeding in Germany as an example to show how an organic breeding program without biotechnology could be organised. As basis, breeding planning on different breeding plans is carried out: the breeding program in place, a breeding program with buck rotation within “buck circles” and a breeding program with AI are evaluated. It can be shown that within smaller populations (here: goat breeding in South Germany) a buck rotation scheme with progeny testing is superior in genetic gain than the actual and a breeding program based on AI. In a second step, in discussions with different stakeholders and farmers the hygiene plan of the buck circle was discovered as the critical point. A detailed hygiene plan has to be worked out and agreed upon by all participants. Still, the participating farmers have to trust all members of the group, because the compliance with the regulations is only limited controllable

Generating realistic scaled complex networks

Research on generative models plays a central role in the emerging field of network science, studying how statistical patterns found in real networks could be generated by formal rules. Output from these generative models is then the basis for designing and evaluating computational methods on networks including verification and simulation studies. During the last two decades, a variety of models has been proposed with an ultimate goal of achieving comprehensive realism for the generated networks. In this study, we (a) introduce a new generator, termed ReCoN; (b) explore how ReCoN and some existing models can be fitted to an original network to produce a structurally similar replica, (c) use ReCoN to produce networks much larger than the original exemplar, and finally (d) discuss open problems and promising research directions. In a comparative experimental study, we find that ReCoN is often superior to many other state-of-the-art network generation methods. We argue that ReCoN is a scalable and effective tool for modeling a given network while preserving important properties at both micro- and macroscopic scales, and for scaling the exemplar data by orders of magnitude in size

Optical spectroscopy of EX Lupi during quiescence and outburst: Infall, wind, and dynamics in the accretion flow

We explore the accretion mechanisms in EX Lupi, prototype of EXor variables, during its quiescence and outburst phases. We analyse high-resolution optical spectra taken before, during, and after its 2008 outburst. In quiescence and outburst, the star presents many permitted emission lines, including typical CTTS lines and numerous neutral and ionized metallic lines. During the outburst, the number of emission lines increases to over a thousand, with narrow plus broad component structure (NC+BC). The BC profile is highly variable on short timescales (24-72h). An active chromosphere can explain the metallic lines in quiescence and the outburst NC. The dynamics of the BC line profiles suggest an origin in a hot, dense, non-axisymmetric, and non-uniform accretion column that suffers velocity variations along the line-of-sight on timescales of days. Assuming Keplerian rotation, the emitting region would be located at ~0.1-0.2 AU, consistent with the inner disk rim, but the velocity profiles of the lines reveal a combination of rotation and infall. Line ratios of ions and neutrals can be reproduced with a temperature of T~6500 K for electron densities of a few times 10$^{12}$cm$^{-3}$ in the line-emitting region. The data confirm that the 2008 outburst was an episode of increased accretion, albeit much stronger than previous EX Lupi and typical EXors outbursts. The line profiles are consistent with the infall/rotation of a non-axisymmetric structure that could be produced by clumpy accretion during the outburst phase. A strong inner disk wind appears in the epochs of higher accretion. The rapid recovery of the system after the outburst and the similarity between the pre-outburst and post-outburst states suggest that the accretion channels are similar during the whole period, and only the accretion rate varies, providing a superb environment for studying the accretion processes.Comment: 15 pages plus 26 pages online material, accepted by A&