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An Improved Algorithm for the Periodic Timetabling Problem
No full textWe consider the computation of periodic timetables, which is a key task in the service design process of public transportation companies. We propose a new approach for solving the periodic timetable optimisation problem. It consists of a (partially) heuristic network aggregation to reduce the problem size and make it accessible to standard mixed-integer programming (MIP) solvers. We alternate the invocation of a MIP solver with the well-known problem specific modulo network simplex heuristic (ModSim). This iterative approach helps the ModSim-method to overcome local minima efficiently, and provides the MIP solver with better initial solutions. Our computational experiments are based on the 16 railway instances of the PESPlib, which is the only currently available collection of periodic event scheduling problem instances. For each of these instances, we are able to reduce the objective values of previously best known solutions by at least 10.0%, and up to 22.8% with our iterative combined method
Evaluation of defect formation in helium irradiated Y2O3 doped W-Ti alloys by positron annihilation and nanoindentation
No full textHelium implanted tungsten-titanium ODS alloys are investigated using positron annihilation spectroscopy and nanoindentation. Titanium reduces the brittleness of the tungsten alloy, which is manufactured by mechanical alloying. The addition of Y2O3 nanoparticles increases the mechanical properties at elevated temperature and enhances irradiation resistance. Helium ion implantation was applied to simulate irradiation effects on these materials. The irradiation was performed using a 500 kV He ion implanter at fluences around 5 × 1015 cm−2 for a series of samples both at room temperature and at 600 °C. The microstructure and mechanical properties of the pristine and irradiated W-Ti-ODS alloy are compared with respect to the titanium and Y2O3 content. Radiation damage is studied by positron annihilation spectroscopy analyzing the lifetime and the Doppler broadening. Three types of helium-vacancy defects were detected after helium irradiation in the W-Ti-ODS alloy: small defects with high helium-to-vacancy ratio (low S parameter) for room temperature irradiation, larger open volume defects with low helium-to-vacancy ratio (high S parameter) at the surface and He-vacancy complexes pinned at nanoparticles deeper in the material for implantation at 600 °C. Defect induced hardness was studied by nanoindentation. A drastic hardness increase is observed after He ion irradiation both for room temperature and elevated irradiation temperature of 600 °C. The Ti alloyed tungsten-ODS is more affected by the hardness increase after irradiation compared to the pure W-ODS alloy
A pilot study on fingerprinting Leishmania species from the Old World using Fourier transform infrared spectroscopy
No full textLeishmania species are protozoan parasites and the causative agents of leishmaniasis, a vector borne disease that imposes a large health burden on individuals living mainly in tropical and subtropical regions. Different Leishmania species are responsible for the distinct clinical patterns, such as cutaneous, mucocutaneous, and visceral leishmaniasis, with the latter being potentially fatal if left untreated. For this reason, it is important to perform correct species identification and differentiation. Fourier transform infrared spectroscopy (FTIR) is an analytical spectroscopic technique increasingly being used as a potential tool for identification of microorganisms for diagnostic purposes. By employing mid-infrared (MIR) spectral data, it is not only possible to assess the chemical structures but also to achieve differentiation supported by multivariate statistic analysis. This work comprises a pilot study on differentiation of Leishmania species of the Old World (L. major, L. tropica, L. infantum, and L. donovani) as well as hybrids of distinct species by using vibrational spectroscopic fingerprints. Films of intact Leishmania parasites and their deoxyribonucleic acid (DNA) were characterized comparatively with respect to their biochemical nature and MIR spectral patterns. The strains’ hyperspectral datasets were multivariately examined by means of variance-based principal components analysis (PCA) and distance-based hierarchical cluster analysis (HCA). With the implementation of MIR spectral datasets we show that a phenotypic differentiation of Leishmania at species and intra-species level is feasible. Thus, FTIR spectroscopy can be further exploited for building up spectral databases of Leishmania parasites in view of high-throughput analysis of clinical specimens
Conceptual study for long-term monitoring of chemotherapeutic induced cell reactions by ESPI
No full textDuring the last years, various approaches on an individualized drug therapy for benign cells have been researched. However, due to the complex topic a universal approach has not been found up until this point. Commonly, the effect of cytotoxic drugs on benign cells is in most cases the same compared to regular cells while the actual effect on patient still can't be predicted. In order to reduce unwanted side effects or unspecific drug reactions a test system for patients which allows to analyse the interaction between cytotoxic agents and the targeted cells is needed. Furthermore, this should also include an adequate measurement system which is capable to work in a natural environment and without any additional preparation. In terms of this work, a first proof of concept with different benign cells and cytotoxic agents is presented while monitoring the obtained displacement using electronic speckle pattern interferometry (ESPI)
Standardization and quality management in next-generation sequencing
No full textDNA sequencing continues to evolve quickly even after > 30 years. Many new platforms suddenly appeared and former established systems have vanished in almost the same manner. Since establishment of next-generation sequencing devices, this progress gains momentum due to the continually growing demand for higher throughput, lower costs and better quality of data. In consequence of this rapid development, standardized procedures and data formats as well as comprehensive quality management considerations are still scarce. Here, we listed and summarized current standardization efforts and quality management initiatives from companies, organizations and societies in form of published studies and ongoing projects. These comprise on the one hand quality documentation issues like technical notes, accreditation checklists and guidelines for validation of sequencing workflows. On the other hand, general standard proposals and quality metrics are developed and applied to the sequencing workflow steps with the main focus on upstream processes. Finally, certain standard developments for downstream pipeline data handling, processing and storage are discussed in brief. These standardization approaches represent a first basis for continuing work in order to prospectively implement next-generation sequencing in important areas such as clinical diagnostics, where reliable results and fast processing is crucial. Additionally, these efforts will exert a decisive influence on traceability and reproducibility of sequence data
Elektrogesponnene Polymerfasern als neuartiges Material für die Bioelektrokatalyse des Enzyms Pyrrolochinolinchinon-abhängige Glucosedehydrogenase
No full textEs wurde ein dreidimensionales Polymerfasernetzwerk aufgebaut, charakterisiert und anschließend daran das Enzym Pyrrolochinolinchinon-abhängige Glukosedehydrogenase (PQQ)GDH gebunden. Das Polymerfasernetzwerk wurde durch Elektrospinnen einer Mischung des Polymers Polyacrylnitril und verschiedener leitfähiger Polymere der Polyanilin-Familie auf Indium-Zinn-Oxid-Elektroden aufgebracht. Die so hergestellten Fasermatten erwiesen sich bei mikroskopischen Untersuchungen gleichförmig präpariert und die Faserdurchmesser bewegten sich im Bereich weniger hundert Nanometer. Das Redoxpaar Kaliumhexacyanoferrat (II/III) zeigte an diesen Polymer-Elektrodenstrukturen eine quasi-reversible Elektrochemie. Bei weitergehenden Untersuchungen an den enzymmodifizierten Fasern ((PQQ)GDH) konnten unter Substratzugabe (Glukose) bioelektrokatalytische Ströme nachgewiesen werden. Das Fasernetzwerk fungiert hier nicht nur als Immobilisierungsmatrix, sondern als auch als Teil des Signalwandlers.A three-dimensional polymeric electrode structure was developed, characterized and subsequently coupled with the enzyme pyrroloquinoline quinone-dependent Glucosedehydrogenase (PQQ)GDH. The polymeric fiber network is produced by means of electrospinning from mixtures of polyacrylonitrile (PAN) and three different sulfonated poylanilines on top of ITO electrodes. The mats are uniform in their overall appearance; average diameters of the fibers produced are in the range of a few hundred nanometers. These polymeric structures can be shown to allow electrochemical conversions as verified with the ferri-/ferrocyanide redox couple. In addition, application in bioelectrocatalysis can be demonstrated. For two of three selected blends of PAN with sulfonated polyanillines, a well-defined bioelectrochemical response is obtained upon covalent fixation of PQQ-GDH to the fiber network and subsequent addition of substrate glucose. The electrospun matrix does not only act here as an immobilization support, but at the same time as a transducing element
Safety & Security – Sicherheit und Sicherheit im Zeitalter kommunizierender Fahrzeuge
No full textGlobale Megatrends wie die Digitalisierung, Internet of Things (IoT) oder Software Defined Everything beeinflussen die Zukunft des Automobils in nie dagewesener Weise und Geschwindigkeit (Dannenberg & Burgard 2015). OEM entwickeln unter diesem Druck, moderne Car2X-Services, um die Attraktivität ihrer Modelle zu steigern. Offene Standards werden es auch bisher branchenfremden Playern ermöglichen, Applikationen zu entwickeln, die sich außerhalb der »Hoheit« der OEM befinden (Borchert & Slusser 2014). Der Austausch von Informationen von Fahrzeugen mit jedem nur denkbaren externen Kommunikationspartner bricht mit dem Paradigma, dass das Fahrzeug ein in sich geschlossenes System sei (Harding et al. 2014). Der Einsatz von Diensten der klassischen Informationstechnologie im Fahrzeug führt zu Sicherheitsrisiken, die in der Branche bisher bestenfalls aus Büro- oder Produktionsumgebungen bekannt waren. Die Auswirkungen für die Sicherheit des Gesamtfahrzeuges sind gravierend.
Das Management der Sicherheit elektrischer, elektronischer oder programmierbarer Fahrzeugsysteme ist daher nicht mehr nur auf die Funktionale Sicherheit (Safety) beschränkt, sondern muss den Aspekten der Vertraulichkeit, Integrität und Verfügbarkeit (Security) Rechnung tragen.
Die Herausforderung besteht in der Beantwortung der Fragen, ob die bestehenden Ansätze aus der Informationstechnologie den Anforderungen der Branche gerecht werden und die beteiligten Experten beider Fachrichtungen zueinander finden und die jeweils andere Seite verstehen. Innerhalb der ISO wird zurzeit ein Projektvorschlag zur ISO 26262 in Verbindung mit dem Management der Informationssicherheit diskutiert
Advanced Nanophotonics: Silicon-Organic Hybrid Technology
No full textIntegrated photonic devices have gained increasing research interests. Especially silicon photonics have become very attractive for various optical applications. Using silicon-on-insulator as a material platform provides the ability to fabricate photonic devices with electronic devices on a single chip. Driven by substantial research investments, the integration of photonic devices on silicon-on-insulator substrates has reached a degree of maturity that already permits industrial adoption. However, silicon has the disadvantage of linear electro-optical effects, and, therefore, advanced modulation formats are difficult to realize when using silicon-based high-speed modulators. Hence, a new approach was proposed: the silicon-organic hybrid technology. This technology is a viable extension of the silicon-on-insulator material system for efficient high-speed modulation. We herewith present our theoretical and experimental investigations of the silicon-organic hybrid slot-waveguide ring resonator. The advanced device design is described in detail, which allows using both, the efficient silicon-on-insulator strip-waveguides and the silicon-organic hybrid slot-waveguides in single ring resonator. For the first time, we report the transmission spectra of such a resonator covered with an electro-optical polymer.Integrierte photonische Bauelemente werden in der Forschung immer bedeutender. Besonders die Siliziumphotonik ist für verschiedene optische Anwendungen sehr attraktiv. Die Verwendung von Silizium-auf-Isolator-Materialsystemen bietet die Möglichkeit, photonische Bauelemente mit elektronischen Geräten auf einem einzelnen Chip zu entwickeln. Durch erhebliche Forschungsinvestitionen hat die photonische Integration auf Silizium-auf-Isolator-Substraten einen Reifegrad, der bereits Industriemaßstäben genügt. Jedoch hat Silizium keinen linearen elektrooptischen Effekt und damit sind moderne Modulationsformate nur schwierig zu realisieren. Daher wird seit eingen Jahren ein neuer Ansatz, die Silizium-Organik Hybridtechnologie, verfolgt. Diese Technologie ist eine tragfähige Ausdehnung des Silizium-auf-Isolator-Materialsystems für eine effiziente Hochgeschwindigkeitsmodulation und optische Signalverarbeitung. In diesem Artikel präsentieren wir unsere theoretischen und experimentellen Untersuchungen zu einem Silizium-Organik Hybrid Ringresonator. Das Design und die Herstellung des neuartigen nanophotonischen Bauelements werden im Detail beschrieben. Der demonstrierte Ringresonator kombiniert die Vorteile zweier verschiedener Wellenleiterarten in einem einzelnen Ring, dem verlustarmen Kanal-Wellenleiter und dem Silizium-organischen Hybridschlitzwellenleiter. Wir demonstrieren erstmals ein Transmissionsspektrum eines solchen Ringresonators, der mit einem elektro-optischen Polymer beschichtet ist
Szenarien zur Transformation von Energieversorgungssystemen als Voraussetzung für die Ableitung von Anforderungen an zukünftige Kompetenzen
No full textDie Transformation von Energieversorgungssystemen ist durch ein hohes Maß an Unsicherheiten gekennzeichnet. Dies trifft auch auf die Frage zu, welche Qualifikationen und Kompetenzen in der Zukunft notwendig sind, um im Transformationsprozess passfähig zu sein. Eine Möglichkeit des Umgangs mit diesen Unsicherheiten besteht in der systematischen Herausarbeitung von Anforderungen an Qualifikationen und Kompetenzen, die sich auf die Antizipation von möglichen Zukünften der Energieversorgung stützt. Aus diesem Grund gehen die Autoren in ihrem Beitrag der Frage nach, wie diese Anforderungen an Qualifikationen und Kompetenzen bei der Transformation von Energieversorgungssystemen systematisch ermittelt werden können. Hierbei greifen sie auf den Transformationsansatz bzw. die Multi Level Perspective (englisch) zurück und entwickeln ihren Ansatz für ein spezifisches Szenarioanalyse-Design. Im Anschluss daran werden Anforderungen an Qualifikationen und Kompetenzen vor dem Hintergrund unterschiedlicher Szenarien abgeleitet.The transformation of energy supply systems is characterized by a high degree of uncertainty. This also applies to the question, which skills and competencies are needed in the future in order to be suitable in the transformation process. One way of dealing with these uncertainties is the systematic elaboration of requirements for skills and competences, which is based on the anticipation of possible futures of the energy supply. Thus, the authors discuss how such requirements for qualifications and skills can be systematically identified. The authors use the transformation approach, respectively the multi-level perspective, and, on this basis, develop an approach for the specific design of a scenario analysis. Subsequently, requirements for qualifications and competences are derived
Prozesse, Technologie, Anwendungen, Systeme und Management 2016 : Tagungsband zur 29. AKWI-Jahrestagung vom 11.09.2016 bis 14.09.2016 an der Technischen Hochschule Brandenburg
No full textTagungsbeiträge aus den Bereichen Geschäftsprozesse, Informationssysteme – IT-Management, Cloud – Mobile – Security und Didaktik – Wissensmanagemen