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See detailDemontage von Elektroantrieben mit Assistenzrobotern zum wirtschaftlichen Recycling
Jungbluth, Jan UL; Plapper, Peter UL; Gerke, Wolfgang

in Tagungsband AALE 2016 (2016)

Die zerstörungsfreie Demontage zum Zweck der Refrabrikation oder des höherwertigem Produktrecyclings findet nur selten im industriellen Umfeld Anwendung. Allerdings ist mit einem Anstieg dieses trennenden ... [more ▼]

Die zerstörungsfreie Demontage zum Zweck der Refrabrikation oder des höherwertigem Produktrecyclings findet nur selten im industriellen Umfeld Anwendung. Allerdings ist mit einem Anstieg dieses trennenden Fertigungsverfahrens in naher Zukunft zu rechnen da die immer stärker begrenzten und zugänglichen Ressourcen durch strengere Gesetze im Rahmen der Abfallwirtschaft gesichert werden müssen. Zum Beispiel wurden durch das Kreislaufwirt-schaftsgesetz der europäischen Union [1] die Hersteller dazu verpflichtet Rücknahmesysteme für elektrische und elektronische Geräte zu schaffen um sie einer weiteren wirtschaftlichen Nutzung oder umweltgerechten Entsorgung zugänglich zu machen. Für die umweltgerechte Entsorgung ist eine wertstoffgerechte Trennung der Produktkomponenten vorgesehen. Aus wirtschaftlichen Gründen erfolgt diese Materialtrennung meist verfahrenstechnisch durch Zerkleinern und Sortieren der Wertstoffe. Die weitere wirtschaftliche Nutzung ganzer Kompo-nenten wird, trotz hoher Einsparpotenziale [2], durch den Aufwand der Refabrikation kaum in Betracht gezogen. Denn die zerstörungsfreie Trennung kann bisher meist nur manuell und damit kostenintensiv erfolgen. In der Folge werden gerade im Bereich der Elektroschrottver-wertung häufig illegale Entsorgungswege über das außereuropäische Ausland gewählt [3]. Zur Verbesserung der Wirtschaftlichkeit der Demontage bietet oft die Automatisierung Lösun-gen. Um diesen Sektor der Automatisierung zugänglich zu machen, erfolgten bereits For-schungsaktivitäten zur Automatisierung der Demontage von Fernsehgeräten [4] und PCs [5]. Das Ergebnis dieser Studien zeigt, dass durch die hohe Variation der Produktgestalt oder aufgrund von Beschädigungen der Produkte, der [less ▲]

Detailed reference viewed: 202 (10 UL)
See detaildenmpc
Dentler, Jan Eric UL

Software (2017)

This package is providing an object oriented real-time nonlinear model predictive control (NMPC) framework which developed at the Automation & Robotics Research Group http://wwwde.uni.lu/snt/research ... [more ▼]

This package is providing an object oriented real-time nonlinear model predictive control (NMPC) framework which developed at the Automation & Robotics Research Group http://wwwde.uni.lu/snt/research/automation_robotics_research_group at the University of Luxembourg. It features a modularization for multi-agent systems which allows the on-line change of agents, control objectives, constraints and couplings, triggered by ROS-messages. [less ▲]

Detailed reference viewed: 158 (20 UL)
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See detailDerivative recovery and a posteriori error estimate for extended finite elements
Bordas, Stéphane UL; Duflot, M.

in Computer Methods in Applied Mechanics & Engineering (2007), 196(35-36), 3381-3399

This paper is the first attempt at error estimation for extended finite elements. The goal of this work is to devise a simple and effective local a posteriori error estimate for partition of unity ... [more ▼]

This paper is the first attempt at error estimation for extended finite elements. The goal of this work is to devise a simple and effective local a posteriori error estimate for partition of unity enriched finite element methods such as the extended finite element method (XFEM). In each element, the local estimator is the L2 norm of the difference between the raw XFEM strain field and an enhanced strain field computed by extended moving least squares (XMLS) derivative recovery obtained from the raw nodal XFEM displacements. The XMLS construction is tailored to the nature of the solution. The technique is applied to linear elastic fracture mechanics, in which near-tip asymptotic functions are added to the MLS basis. The XMLS shape functions are constructed from weight functions following the diffraction criterion to represent the discontinuity. The result is a very smooth enhanced strain solution including the singularity at the crack tip. Results are shown for two- and three-dimensional linear elastic fracture mechanics problems in mode I and mixed mode. The effectivity index of the estimator is close to 1 and improves upon mesh refinement for the studied near-tip problem. It is also shown that for the linear elastic fracture mechanics problems treated, the proposed estimator outperforms one of the superconvergent patch recovery technique of Zienkiewicz and Zhu, which is only C0. Parametric studies of the general performance of the estimator are also carried out. © 2007 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 133 (3 UL)
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See detailDeriving essential components of lean and industry 4.0 assessment model for manufacturing SMEs
Kolla, Sri Sudha Vijay Keshav UL; Minoufekr, Meysam UL; Plapper, Peter UL

in 52nd CIRP Conference on Manufacturing Systems (CMS) (2019), 81

Quantifying lean and ICT architecture related to Industry 4.0 is a new challenge in Small and Medium Scale Enterprises (SMEs) that needs to be addressed by both research as well as enterprises themselves ... [more ▼]

Quantifying lean and ICT architecture related to Industry 4.0 is a new challenge in Small and Medium Scale Enterprises (SMEs) that needs to be addressed by both research as well as enterprises themselves. Especially in the manufacturing sector, SMEs need to transform themselves into emerging trends such as industry 4.0 while practicing existing manufacturing philosophies such as Lean Production Systems (LPS) to be competitive in global markets. The major concern is that there are many assessment models available to measure the status of an enterprise related to either LPS or Industry 4.0. Often, these models are complex and don’t fulfill the requirements of manufacturing SMEs. On the other hand, most of the models only consider either lean or industry 4.0 elements. The outcomes of this research help to develop a hybrid model including both lean and industry 4.0 features suitable for manufacturing SMEs. The main objective of this research is to provide state of the art literature on existing assessment models and consequently map lean and industry 4.0 components to the specific characteristics of manufacturing SMEs. The paper concludes with a summary and outlook for our future research. [less ▲]

Detailed reference viewed: 65 (2 UL)
See detailDesign and Implementation of a Reliable Distributed Energy Management System
Hoben, Ralf UL

Doctoral thesis (2011)

Detailed reference viewed: 59 (6 UL)
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See detailDesign Automation With the Characteristics Properties Model and Property Driven Design for Redesign
Qureshi, Ahmed Jawad UL; Eisenbart, Boris UL; Dantan, Jean-Yves et al

in Abramovici, Michael, Stark, Rainer (Ed.) Smart Product Engineering (2013)

This paper presents a framework consisting of a mathematical model and an algorithm for representation, analysis and exploration of the design space in redesign problems. The framework develops and ... [more ▼]

This paper presents a framework consisting of a mathematical model and an algorithm for representation, analysis and exploration of the design space in redesign problems. The framework develops and extends the existing formalism of the Characteristics Properties Model (CPM) and Property Driven Design (PDD). A platform independent quantitative model based on formal log-ic is presented to map the characteristics and properties, as well as the relations and dependencies between them, along with the necessary conditions for solu-tion evaluation. The model is based on generalization of existing mathematical design models and is supported by the development of an algorithm enabling property driven design. The resulting framework offers a rich and flexible syn-tax and vocabulary along with a mathematical and computational tool applica-ble to mechanical product redesign. [less ▲]

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See detailDesign process ingredients: a comparison between group and individual work
Dwarakanath, S.; Blessing, Lucienne UL

in Cross, N.; Christiaans, H.; Dorst, K. (Eds.) Analysing Design Activity (1994)

In this paper a comparison is made between the design processes of an individually working designer and of a group of designers based on protocol analysis. The analysis focused on the differences and ... [more ▼]

In this paper a comparison is made between the design processes of an individually working designer and of a group of designers based on protocol analysis. The analysis focused on the differences and similarities in the ingredients of the two processes. The basic ingredients used for the analysis were: Issues, Arguments, Alternatives, Criteria, Decisions, External information, and Others. Comparisons have been made between: the group as a whole and the individual designer; the individual group members; the individual group members and the individual designer. The results provide a first step towards a better understanding of the differences between group and individual work. The paper also discusses some of the limitations of this type of study. [less ▲]

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See detailDesigning collaborative scenarios on tangible tabletop interfaces - insights from the implementation of paper prototypes in the context of a multidisciplinary design workshop
Sunnen, Patrick UL; Arend, Béatrice UL; Heuser, Svenja UL et al

in Proceedings of the 17th European Conference on Computer-Supported Cooperative Work: The International Venue on Practice-centred Computing and the Design of Cooperation Technologies - Exploratory Papers, Reports of the European Society for Socially Embedded Technologies (2019, June)

Within the context of the research project ORBIT (Overcoming Breakdowns in Teams with Interactive Tabletops), we design and study a joint problem-solving activity at an interactive tabletop, that gives ... [more ▼]

Within the context of the research project ORBIT (Overcoming Breakdowns in Teams with Interactive Tabletops), we design and study a joint problem-solving activity at an interactive tabletop, that gives participants the opportunity to develop their collaboration methods. To gain design insights for the development of a scenario soliciting participants to collaborate, we set up a multidisciplinary design workshop. During the latter, we explored and discussed three different collaborative scenarios, implemented as paper prototypes. In this paper, we report on first results gained from an exploratory analysis of the video data that was recorded in the context of this workshop. [less ▲]

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See detailDesigning Meaning to Change Consumer Behaviour: An Exploration
Waltersdorfer, Gregor UL; Gericke, Kilian UL; Blessing, Lucienne UL

in Chakrabarti, Amaresh (Ed.) ICoRD’15 – Research into Design Across Boundaries Volume 1: Theory, Research Methodology, Aesthetics, Human Factors and Education (2015)

The focus of our research is to support designers in fostering a more sustainable behaviour of consumers by creating meaning in products and services. The paper describes the results of a literature study ... [more ▼]

The focus of our research is to support designers in fostering a more sustainable behaviour of consumers by creating meaning in products and services. The paper describes the results of a literature study into the process of meaning making and the mechanisms through which meaning affects consumer behaviour. Meaning is defined as a mental representation of possible relationships. An initial model, the Meaning-Behaviour Model, is presented, integrating the mechanisms found in literature. Five possible interventions, derived from the model, show how designers can use meaning as a lever to foster enduring behavioural change. The paper contributes to the discussion of introducing meaning through design by exploring the link between meaning and behaviour. [less ▲]

Detailed reference viewed: 175 (8 UL)
See detailDesigning Sustainable Technologies, Products and Policies
Benetto, Enrico; Gericke, Kilian UL; Guiton, Mélanie

Book published by Springer (2018)

This book provides insight into the implementation of Life Cycle approaches along the entire business value chain, supporting environmental, social and economic sustainability related to the development ... [more ▼]

This book provides insight into the implementation of Life Cycle approaches along the entire business value chain, supporting environmental, social and economic sustainability related to the development of industrial technologies, products, services and policies; and the development and management of smart agricultural systems, smart mobility systems, urban infrastructures and energy for the built environment. The book is based on papers presented at the 8th International Life Cycle Management Conference that took place from September 3-6, 2017 in Luxembourg, and which was organized by the Luxembourg Institute of Science and Technology (LIST) and the University of Luxembourg in the framework of the LCM Conference Series. [less ▲]

Detailed reference viewed: 135 (4 UL)
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See detailDetecting User Mode Linux Honeypots is fine ... but it's better to crash them.
Wagener, Gerard UL; Raynal, Frédéric; Dulaunoy, Alexandre et al

Scientific Conference (2008)

Detailed reference viewed: 42 (0 UL)
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See detailDeterministic analysis of distributed order systems using operational matrix
Duong, Pham UL

in Applied Mathematical Modelling (2016), 40(3), 1929-1940

"Recently, distributed order systems as a generalized concept of fractional order have been a" "major focus in science and engineering areas, and have rapidly extended application across a wide range of ... [more ▼]

"Recently, distributed order systems as a generalized concept of fractional order have been a" "major focus in science and engineering areas, and have rapidly extended application across a wide range of disciplines. However, only a few numerical methods are available for analyzing the distributed order systems. This paper proposes a novel numerical scheme to analyze the behavior of single input single output linear systems in the time domain with a single dis- tributed order differentiator/integrator by using operational matrix technique. The proposed method reduces different analysis problems to a system of algebraic equations by using block pulse functions, which makes it easy to handle an arbitrary input. Numerical examples were used to illustrate the accuracy and computational efficiency of the proposed method. The pro- posed method was found to be an efficient tool for analyzing linear distributed order systems." [less ▲]

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See detailDeveloping and Evaluating a Computerized Adaptive Mathematical Test
Schiltz, Jang UL

in Stemmler, Mark; Lautsch, Erwin; Martinke, Dirk (Eds.) Configural Frequency Analysis (CFA) and other non-parametrical methods: Gustav A. Lienert Memorial Issue. (2008)

The theoretical basis underlying the construction of a CAT is summed up and the item response theory explained. In comparison with a classical paper-and-pencil test, the characteristics and the advantages ... [more ▼]

The theoretical basis underlying the construction of a CAT is summed up and the item response theory explained. In comparison with a classical paper-and-pencil test, the characteristics and the advantages of a CAT are exposed. After performing a thorough analysis of the data, we developed a CAT based on the responses of 3590 children to a standardized mathematical test. The software presents a great amount of flexibility and allows treating multiple-choice items, as well as items with free response options and graphical items. Some results of an empirical evaluating study are presented. We showed that qualities of power, flexibility and economy of time of the CAT do not imply the loss of the classical psychometric properties of a paper-and-pencil test; we analyze the carry-over effect between the computerized and the paper-and-pencil test situation and as well as the relations between mathematical skills and general cognitive abilities. [less ▲]

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See detailDeveloping composite nanofibre fabrics using electrospinning, ultrasonic sewing, and laser cutting technologies
Trejo, Nidia; Reyes, Catherine UL; Sanchez, Vanessa et al

in International Journal of Fashion Design, Technology and Education (2016), 9(3), 192-200

In this study, we combine Nylon 6 nanomembranes with tulle and organza fashion fabrics to construct a full-scale, flying kite. For the first time, this work demonstrates the processing of electrospun ... [more ▼]

In this study, we combine Nylon 6 nanomembranes with tulle and organza fashion fabrics to construct a full-scale, flying kite. For the first time, this work demonstrates the processing of electrospun nanofabrics using laser cut and ultrasonic technologies. The composite fabrics were analysed for their morphological and mechanical properties. The fracture strain of the nanomembrane–tulle composites increased 58–171% compared to the control samples due to nanofibre entanglements on the open weave structure of tulle. The ultrasonic sewn fabric regions endured 169% greater applied stress with the addition of the organza fabric and the seaming process compared to the nanomembrane–tulle composite. [less ▲]

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See detailDevelopment and Application of an Asymptotic Level Transport Pollution Model for Luxembourg Energy Air Quality Project
Aleluia Da Silva Reis, Lara UL

Doctoral thesis (2013)

The connections between air pollution and the increase of respiratory diseases, are well known. In Europe, many efforts have been carried out towards the mitigation of the pollutants’ emissions over the ... [more ▼]

The connections between air pollution and the increase of respiratory diseases, are well known. In Europe, many efforts have been carried out towards the mitigation of the pollutants’ emissions over the last decades. The European Union supports the implementation of structural planning measures to control air pollution. The assessment and evaluation of these air quality policies must be carried out with the help of dedicated integrated assessment models. The use of integrated assessment models, which combine models from different fields, raises the need for developing specific modelling concepts in order to provide results to support policy decisions within a practical time frame. This work presents the methodology and the development of a dedicated air quality model for an integrated assessment model. This approach has been designed for the Luxembourg Energy and Air Quality, LEAQ, integrated assessment model. It combines an air quality model, AUSTAL2000-AYLTP, with a techno-economic model, ETEM, which computes ozone precursors emissions related to energy consumption. The models are coupled via an optimization engine, which minimizes the total energy cost for a given ozone level. AUSTAL2000, a Lagrangian transport model, has been adapted to receive a photochemical module, the AsYmptotic Level Transport Pollution, AYLTP. This module consists of a Look-Up Table of quasi-linear reaction rates. A balance has been found that gives an acceptable level of accuracy, given the reduction of computational time. The results of the air quality model have been compared with measurements, and with the regional model LOTOS-EUROS and are considered satisfactory for this type of approach. Regarding the LEAQ framework, two study cases have been simulated, one including only the national emissions from Luxembourg country, and a second one for the Luxembourg region, including the neighbouring countries emissions. [less ▲]

Detailed reference viewed: 102 (6 UL)
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See detailDevelopment of an integrated omics in silico workflow and its application for studying bacteria-phage interactions in a model microbial community
Narayanasamy, Shaman UL

Doctoral thesis (2017)

Microbial communities are ubiquitous and dynamic systems that inhabit a multitude of environments. They underpin natural as well as biotechnological processes, and are also implicated in human health. The ... [more ▼]

Microbial communities are ubiquitous and dynamic systems that inhabit a multitude of environments. They underpin natural as well as biotechnological processes, and are also implicated in human health. The elucidation and understanding of these structurally and functionally complex microbial systems using a broad spectrum of toolkits ranging from in situ sampling, high-throughput data generation ("omics"), bioinformatic analyses, computational modelling and laboratory experiments is the aim of the emerging discipline of Eco-Systems Biology. Integrated workflows which allow the systematic investigation of microbial consortia are being developed. However, in silico methods for analysing multi-omic data sets are so far typically lab-specific, applied ad hoc, limited in terms of their reproducibility by different research groups and suboptimal in the amount of data actually being exploited. To address these limitations, the present work initially focused on the development of the Integrated Meta-omic Pipeline (IMP), a large-scale reference-independent bioinformatic analyses pipeline for the integrated analysis of coupled metagenomic and metatranscriptomic data. IMP is an elaborate pipeline that incorporates robust read preprocessing, iterative co-assembly, analyses of microbial community structure and function, automated binning as well as genomic signature-based visualizations. The IMP-based data integration strategy greatly enhances overall data usage, output volume and quality as demonstrated using relevant use-cases. Finally, IMP is encapsulated within a user-friendly implementation using Python while relying on Docker for reproducibility. The IMP pipeline was then applied to a longitudinal multi-omic dataset derived from a model microbial community from an activated sludge biological wastewater treatment plant with the explicit aim of following bacteria-phage interaction dynamics using information from the CRISPR-Cas system. This work provides a multi-omic perspective of community-level CRISPR dynamics, namely changes in CRISPR repeat and spacer complements over time, demonstrating that these are heterogeneous, dynamic and transcribed genomic regions. Population-level analysis of two lipid accumulating bacterial species associated with 158 putative bacteriophage sequences enabled the observation of phage-host population dynamics. Several putatively identified bacteriophages were found to occur at much higher abundances compared to other phages and these specific peaks usually do not overlap with other putative phages. In addition, there were several RNA-based CRISPR targets that were found to occur in high abundances. In summary, the present work describes the development of a new bioinformatic pipeline for the analysis of coupled metagenomic and metatranscriptomic datasets derived from microbial communities and its application to a study focused on the dynamics of bacteria-virus interactions. Finally, this work demonstrates the power of integrated multi-omic investigation of microbial consortia towards the conversion of high-throughput next-generation sequencing data into new insights. [less ▲]

Detailed reference viewed: 345 (94 UL)
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See detailDevelopments in Mesh-Moving and Mesh-Update Schemes for Space-Time Finite Element Dicretisations of Fluid Flows
Schippke, Henning; Zilian, Andreas UL

Scientific Conference (2011)

Space-time discretisations of physical problems involving moving and deforming bodies, boundaries and interfaces have been shown to offer advantageous properties, while being methodologically uniform and ... [more ▼]

Space-time discretisations of physical problems involving moving and deforming bodies, boundaries and interfaces have been shown to offer advantageous properties, while being methodologically uniform and flexible. Well-known phenomena, which are ideally suited to be analysed by space-time methods, are fluid-structure interaction problems in general as well as fluid flows with subdomain phase boundaries or immersed moving objects. In this contribution existing mesh-moving and mesh-update techniques are comparatively discussed within the framework of finite element discretisations of the Navier-Stokes equations in space and time. The investigation is based on a SUPG/PSPG velocity-pressure formulation on the deforming space-time do- main. Developments of mesh reconnection at fluid-solid interfaces due to mesh-moving/reconnecting proce- dures for space-time discretisations of fluid flows are presented. Furthermore mesh-update/reconnecting techniques are examined occurring in engineering problems involving sliding or rotating space-time fluid meshes. The presented techniques are accompanied by numerical examples of translational fluid flow as well as fluid flow with immersed rotating fluid bodies. The quality of the approximative solution on the moving and deforming mesh as well as its conservation properties are investigated. [less ▲]

Detailed reference viewed: 62 (2 UL)