Detecting User Mode Linux Honeypots is fine ... but it's better to crash them.

Scientific Conference (2008)

Deterministic analysis of distributed order systems using operational matrix

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 ▲]

Developing and Evaluating a Computerized Adaptive Mathematical Test

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 ▲]

Development and Application of an Asymptotic Level Transport Pollution Model for Luxembourg Energy Air Quality Project

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 ▲]

Development of an integrated omics in silico workflow and its application for studying bacteria-phage interactions in a model microbial community

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 ▲]

Developments in Mesh-Moving and Mesh-Update Schemes for Space-Time Finite Element Dicretisations of Fluid Flows

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 ▲]

Digital (r) evolution in private customer business \ "a ft? Call to banks to act proactively

in Die Bank (2012), 52(6), 46--50

Digital History Projects As Boundary Objects

Scientific Conference (2017)

DIGITAL TWIN FRAMEWORK FOR HUMANROBOT INTERACTION BY MEANS OF INDUSTRY 4.0 ENABLING TECHNOLOGIES

Doctoral thesis (2022)

The introduction of Industry 4.0 technologies has shaped the old form of manufactures. Despite the enormous existence of technologies such as IoT, CPS, AI or collaborative and autonomous robots in the ... [more ▼]

The introduction of Industry 4.0 technologies has shaped the old form of manufactures. Despite the enormous existence of technologies such as IoT, CPS, AI or collaborative and autonomous robots in the industrial environment and while the main objective of Industry 4.0 is to implement a better connected, flexible and smarter industrial environment, some aspects still lack to be better integrated and implemented. Among these aspects, the human-robot interaction, collaborative robot programming and simulation which still need many improvements in order to fit in the new smart environments where cobots and humans work together in hybrid teams. This research envisions the future of robot programming and robot simulation in industrial environment where humans and robots work side by side in hybrid teams. The main objective of this work was to build and demonstrate a new digital twin-based framework that is designed to enhance the human-robot interaction, robot programming and realtime in-real-environment simulation. The proposed approach required to afford a flexible real-time service-based framework for both vertical and horizontal integration. It also needed to provide an intuitive and human-friendly usage for any unskilled worker. This dissertation introduces the main six steps of the digital twin for human-robot interaction proposed framework which was adapted and modified from the common 5-C architectural design of CPSs. Its flexible architecture grants a robust integration of new devices, systems or APIs. Since this framework was initially designed for human-robot interaction, its capabilities was demonstrated through a use case study and implementation. The first three-C steps of the method (Connect, Collect and Combine) should be initiated at the beginning but executed only one time during each process life-cycle. Connection establishment between physical and digital worlds is guaranteed in step one. Data Collection from physical devices was done in step two. Combining both worlds in one scene and synchronization between twin models was accomplished during step three. Data analysis, algorithms generation and motion planning are processed in step four. Then, a simulation of digital model generated motions was visualized through mixed reality interfaces and while enabling user interaction was executed during step five. At t he e nd, after approval, robot movements are generated and actions are made by the physical twin. All-along the six steps, an horizontal technological architecture was used. First, an IoT Gateway infrastructure was established to maintain the real-time data exchange between the system’s different components. Then, a MR-based immersive interface was developed through many phases to enable digital world set-up, visualization, simulation and interaction using human gestures. At the meanwhile, a broker was implemented to handle diverse tasks mainly citing the motion planning and the AI-based object pose estimation defining. The broker is also responsible on new elements integration. At the end, implemented system approved the main objectives of the proposed research methodology which are: • Intuitive robot programming: any unskilled worker can program the robot thanks to the human-friendly interface and the autonomous assistance capabilities of the robot while estimating position and planning motions. • Realistic simulation: a simulation done in real environment with unpredicted real conditions and objects. • Flexible system integration: it is easy to integrate new devices and features thanks to the broker master interface that connects all separated elements with all their diverse interfaces and platforms. [less ▲]

Digitizing of Research and Teaching

Scientific Conference (2020, September 05)

The current Covid-19 crisis impacts all manufacturing areas and new processes are sought. This presentation provides the audience with three examples related to assembly work instructions, logistics data ... [more ▼]

The current Covid-19 crisis impacts all manufacturing areas and new processes are sought. This presentation provides the audience with three examples related to assembly work instructions, logistics data handling and manufacturing education, for which innovative ways to obtain access to context sensitive data based on digital tools are investigated. Augmented Reality (AR) and Virtual Reality (VR) facilitate access to relevant manufacturing information. In order to provide logistic warehouse workers with immediate access to shipping documents, to avoid paper print-outs, and to eliminate error-prone typing of information, critical information should be handled digitally and hands-free. To support logistic workers to efficiently document, register and trace receipt, storage or delivery of goods, the presented solution is built on hands-free digital tools with AR technology in commercially available smart glasses. Similarly, workers who execute complex assembly operations frequently require either assistance or support for the next assembly step. Depending on the context, relevant assembly process information is automatically displayed together with the environment in the AR smart glass. Thus, the operator is supported by the presented hands-free-tool to complete the next challenging tasks. Currently, teaching is being transferred from physical class-room teaching to remote or hybrid education. For this purpose, Virtual Reality (VR) provides a very welcome opportunity to complement in-presence teaching with exposure to examples of real manufacturing operations captured in videos of industrial case studies. Students apply learnings from theoretical classes to manufacturing case studies by identifying best practices and also recognizing waste. The presentation shares experience in teaching of lean methods based on AR technology to graduate engineering students. [less ▲]