498 Works

Learning environmental field exploration with computationally constrained underwater robots : Gaussian processes meet stochastic optimal control

Daniel-André Dücker, Andreas René Geist, Edwin Kreuzer & Eugen Solowjow
Autonomous exploration of environmental fields is one of the most promising tasks to be performed by fleets of mobile underwater robots. The goal is to maximize the information gain during the exploration process by integrating an information-metric into the path-planning and control step. Therefore, the system maintains an internal belief representation of the environmental field which incorporates previously collected measurements from the real field. In contrast to surface robots, mobile underwater systems are forced to...

Nanoindentation-based study of the mechanical behavior of bulk supercrystalline ceramic-organic nanocomposites

Büsra Bor, Diletta Giuntini, Berta Domènech Garcia, Michael V. Swain & Gerold A. Schneider
Bulk poly-supercrystalline ceramic-organic nanocomposites were produced and characterized with a nanoindentation-based study. These nanocomposites were processed using two different routines, to compare their properties with and without crosslinking the organic ligands interfacing the ceramic nanoparticles. Together with the expected material strengthening induced by crosslinking, a distinct response emerges when using Berkovich and cube-corner indenters. The supercrystalline materials are prone to compaction, cracking and chipping phenomena that become more severe when a sharper tip is employed,...

Literatur- und Onlinequellen der Lean Construction Studie

Jan Onne Backhaus
Das Literaturverzeichnis der Lean Construction Studie

Real time pose control of an industrial robotic system for machining of large scale components in aerospace industry using laser tracker system

Christian Moeller, Hans Christian Schmidt, Philip Koch, Christian Boehlmann, Simon Kothe, Jörg Wollnack & Wolfgang Hintze
Copyright © 2017 SAE International. The high demand of efficient large scale machining operations by concurrently decreasing operating time and costs has led to an increasing usage of industrial robots in contrast to large scaled machining centers. The main disadvantage of industrial robots used for machining processes is their poor absolute accuracy, caused by the serial construction, resilience of gearings and sensitivity for temperature changes. Additionally high process forces that occur during machining of CFRP...

Isolation and biochemical characterization of a glucose dehydrogenase from a hay infusion metagenome

Alexander Basner & Garabed Antranikian
Glucose hydrolyzing enzymes are essential to determine blood glucose level. A high-throughput screening approach was established to identify NAD(P)-dependent glucose dehydrogenases for the application in test stripes and the respective blood glucose meters. In the current report a glucose hydrolyzing enzyme, derived from a metagenomic library by expressing recombinant DNA fragments isolated from hay infusion, was characterized. The recombinant clone showing activity on glucose as substrate exhibited an open reading frame of 987 bp encoding...

CRISPR/Cas9-facilitated engineering with growth-coupled and sensor-guided in vivo screening of enzyme variants for a more efficient chorismate pathway in E. coli

Minliang Chen, Lin Chen & An-Ping Zeng
Protein engineering plays an increasingly important role in developing new and optimizing existing metabolic pathways for biosynthesis. Conventional screening approach of libraries of gene and enzyme variants is often done using a host strain under conditions not relevant to the cultivation or intracellular conditions of the later production strain. This does not necessarily result in the identification of the best enzyme variant for in vivo use in the production strain. In this work, we propose...

The influence of clamping pressure on joint formation and mechanical performance of Ti6Al4V/CF-PEEK friction-riveted joints

Natascha Zocoller Borba, Jorge F. dos Santos & Sergio T. Amancio-Filho
This work aims at investigating the influence of pre-set clamping pressure on the joint formation and mechanical strength of overlapping direct-friction-riveted joints. A pneumatic fixture device was developed for this work, with clamping pressure varying from 0.2 MPa to 0.6 MPa. A case study on overlapping joints using Ti6Al4V rivets and woven carbon fiber-reinforced polyether-ether-ketone (CF-PEEK) parts were produced. Digital image correlation and microscopy revealed the expected compressive behavior of the clamping system and the...

A review of the application of machine learning and data mining approaches in continuum materials mechanics

Frederic E. Bock, Roland C. Aydin, Christian J. Cyron, Norbert Huber, Surya R. Kalidindi & Benjamin Klusemann
Machine learning tools represent key enablers for empowering material scientists and engineers to accelerate the development of novel materials, processes and techniques. One of the aims of using such approaches in the field of materials science is to achieve high-throughput identification and quantification of essential features along the process-structure-property-performance chain. In this contribution, machine learning and statistical learning approaches are reviewed in terms of their successful application to specific problems in the field of continuum...

The dynamic behaviour of a non-stationary elevator compensating rope system under harmonic and stochastic excitations

Stefan Kaczmarczyk, Radoslaw Marek Iwankiewicz & Yoshiaki Terumichi
Moving slender elastic elements such as ropes, cables and belts are pivotal components of vertical transportation systems such as traction elevators. Their lengths vary within the host building structure during the elevator operation which results in the change of the mass and stiffness characteristics of the system. The structure of modern high-rise buildings is flexible and when subjected to loads due to strong winds and earthquakes it vibrates at low frequencies. The inertial load induced...

Development of a synthetic synovial fluid for tribological testing

Emely Lea Bortel, Baptiste Charbonnier & Roman Heuberger
Wear tests of joint prostheses are usually performed using bovine calf serum. The results from different laboratories are hardly ever comparable as, for example, the protein concentration and the protein composition of the serum-based test liquids vary. In addition, the viscosity of these test liquids is similar to that of water and does not match the more viscous synovial fluid. The present work was aimed at developing a synthetic synovial fluid as an alternative to...

Fail-safe optimization of beam structures

Julian Kajo Lüdeker & Benedikt Kriegesmann
In the current work, a fail-safe optimization of beam structures is carried out. This approach may provide an insight into the robustness of lattice structures. The use of beam elements allows a commonly used engineering approach for obtaining a fail-safe design to be applied. This consists of removing one beam element at a time and optimizing the remaining structure. At the end of the process, the maximum beam radii are used for the final design....

Social Influence, status, and entrepreneurial entry: evidence from the comic book industry

Michael Engel
Diese Dissertation untersucht wie sich die Struktur sozialer Netzwerke auf den unternehmerischen Eintritt auswirkt. Sie analysiert die Effekte von sozialem Einfluss und Status auf die Entscheidung von Personen, ein neues, selbst erstelltes Angebot auf den Markt zu bringen. Bisherige Arbeiten haben diese Effekte zwar nachgewiesen, konnten die zugrundeliegenden Mechanismen aber noch nicht aufdecken. Ausgehend von der Netzwerktheorie leiten wir Hypothesen zu proximitätsbasierten Ansteckungs- und statusbasierten Konvergenzmechanismen ab und testen sie im Kontext der Comic-Industrie mit...

An example of visually supported design of modular product families

Nicolas Gebhardt, Tammo Bahns & Dieter Krause
© 2014 Published by Elsevier B.V. To offer individualized products at globally marketable prices, the Integrated PKT-Approach for Developing Modular Product Families aims to generate high external product variety based on a low internal process and component variety. Specific visualizations are an important factor in the success of this approach. In this paper the Module Interface Graph (MIG) developed at the Institute for Product Development and Mechanical Engineering Design (PKT) is used to show how...

Mobility as a Service: ein Angebot auch für Einkommensarme? (Geo-Datensatz)

Christoph Aberle
Geographic datasets that represent ride-pooling service area in Hamburg as of May 2019: CleverShuttle, Ioki, MOIA, mytaxi match / FREE NOW Including MOIA planned service area extension. All layers have been digitised in May 2019 by using public data provided by the ride-pooling operators. The dataset complements the paper "Mobility as a Service: ein Angebot auch für Einkommensarme?" (DOI 10.15480/882.2395).

Didaktische Unterstützung von Postdocs als strategisches Element der Lehrförderung

Klaus Vosgerau
Für hochschuldidaktische Einrichtungen ist es wesentlich, eine auf die verschiedenen Lehrendengruppen abgestimmte und durch Evidenzen abgesicherte Unterstützung zur Lehre anzubieten. Dies kann maßgeblich dazu beitragen, didaktisches Wissen effizient in die Fachdisziplinen zu transferieren. Nicht zuletzt kann eine bedarfs- und positionsspezifische Förderung nach wesentlichen Zielgruppen die Wahrnehmung einer didaktischen Einrichtung stärken und die Fürsprache in Prozessen hochschulischer Organisationsentwicklung fördern. An Universitäten haben nach den Hochschullehrenden die Postdocs - zusammen mit weiteren, unbefristet beschäftigten Wissenschaftlerinnen und Wissenschaftlern...

A discussion on present theories of rubber friction, with particular reference to different possible choices of arbitrary roughness cutoff parameters

Andrea Genovese, Flavio Farroni, Antonio Papangelo & Michele Ciavarella
Since the early study by Grosch in 1963 it has been known that rubber friction shows generally two maxima with respect to speed - the first one attributed to adhesion, and another at higher velocities attributed to viscoelastic losses. The theory of Klüppel and Heinrich and that of Persson suggests that viscoelastic losses crucially depend on the “multiscale” aspect of roughness and in particular on truncation at fine scales. In this study, we comment a...

Analysis of refrigerant pipe pressure drop of a CO₂ air conditioning unit for vehicles

Christoph Subei & Gerhard Schmitz
This study investigates the pressure drop in refrigerant pipes of a CO₂ automotive air conditioning unit. A test rig to measure the pressure drop of arbitrarily shaped pipes is presented. As boundary conditions at the inlet of the test section, mass flow, pressure and enthalpy of the refrigerant are independently adjustable to values that cover the whole operating range of a CO₂ automotive air conditioning system for cars in the premium segment. Numerical analysis using...

Digital transformation in maritime and city logistics : smart solutions for logistics

This volume contains research contributions by an international group of authors addressing innovative and technology-based approaches for logistics and sustainability. They present simulation studies, systems and models for optimizations and digitalized solutions with a focus on maritime as well port and city logistics. This volume, edited by Carlos Jahn, Wolfgang Kersten, and Christian Ringle, provides valuable insights into digital transformation in logistics with regard to: Maritime and Port Logistics, City Logistics, Sustainability and Business Analytics.

Breaking through the bottlenecks using artificial intelligence

Julia Feldt, Henning Kontny & Axel Wagenitz
Purpose: Performance of Supply Chain is highly dependent on weak spots, so-called bottlenecks. This research paper presents the findings from the analysis of operation processes of a mid-sized producing company and the digital solution for opening up the bottlenecks in order to achieve effectiveness by cutting down the order lead time. Methodology: The study is employing several rounds of simulation based on processes and data from a manufacturing company. Findings: Simulation results demonstrate that by...

Sharing information across company borders in industry 4.0

Kai-Ingo Voigt, Julian Müller, Johannes Veile & Marie-Christin Schmidt
Purpose: Industry 4.0's potentials can only unfold exhaustively if information is shared across company boarders and along supply chains. Exchanging information, however, implies several challenges for companies. This holds especially true if it is transmitted automatically and digitally, as promoted by the concept of Industry 4.0. In response to these challenges, this paper analyzes how information sharing changes in Industry 4.0 contexts. Methodology: Expert interviews with 17 representatives from supply chain management departments of German...

Machine learning in demand planning : cross-industry overview

Nikolas Ulrich Moroff & Saskia Sardesai
Purpose: This paper aims to give an overview about the current state of research in the field of machine learning methods in demand planning. A cross-industry analysis for current machine learning approaches within the field of demand planning provides a decision-making support for the manufacturing industry. Methodology: Based on a literature research, the applied machine learning methods in the field of demand planning are identified. The literature research focuses on machine learning applications across industries...

Akives und forschendes Lernen im Ingenieurstudium : [Vortrag auf der] 72. Plenarversammlung des Fakultätentages für Bauingenieurwesen, Geodäsie und Umweltingenieurwesen (FTBGU)

Klaus Vosgerau
Der Vortrag auf der 72. Plenarversammlung des Fakultätentages für Bauingenieurwesen, Geodäsie und Umweltingenieurwesen (FTBGU) adressiert drei Fragen: Warum sollte Aktives Lernen in den Ingenieurwissenschaften gefördert werden? Warum das Forschende Lernen? Wie können beide Ansätze konkret zu besserem Lernerfolg beitragen? Eine Metastudie zeigt, dass Aktives Lernen die Bestehensquote in großen Lehrveranstaltungen signifikant steigert (Freeman et al., 2014). Mit dem Aktiven Lernen werden zentrale Aspekte des „shift from teaching to learning” (Barr & Tagg, 1995) verbunden. Dies...

Automatic identification system (AIS) data based ship-supply forecasting

Sandra Lechtenberg, Diego de Siqueira Braga & Bernd Hellingrath
Purpose: The bulk cargo shipping industry is characterized by high cost pressure. Chartering vessels at low prices is important to increase the margin of transporting cargo. This paper proposes a three-step, AI-based methodology to support this by forecasting the number of available ships in a region at a certain time. Methodology: Resulting from discussions with experts, this work proposes a threestep process to forecast ship numbers. It implements, compares and evaluates different AI approaches for...

Cyber-attack impact estimation for a port

Sandra König, Stefan Rass & Stefan Schauer
Purpose: We investigate consequences of a cyber-attack on a port through a simulation model. Motivated by the impact of NotPetya on the container company A.P. Møller-Maersk and the entire supply chain we propose a method to estimate the consequences. Such estimation is a first step towards the identification of protection measures. Methodology: We represent a port as a network of interdependent cyber and physical assets. The operational state of each component is measured on a...

Digitalized and autonomous transport – challenges and chances

Sascha Stradner & Uwe Brunner
Purpose: European Logistics is characterized by a matured infrastructure. Nevertheless, industry has to catch up in terms of digitalized and autonomous transport. The awareness-rising of industrial companies in this area is still limited. Therefore, the paper includes a research in order to find out the reasons for hesitations of manufacturing industry. Methodology: For this purpose, an overview of digitalized and autonomous transport based on a literature research is given and reflected at the beginning. The...

Registration Year

  • 2019

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