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Peer Reviewed
See detailControl Theory and Systems Biology
Goncalves, Jorge UL; Warnick, S.

in Iglesias, P. A.; Ingalls, B. P. (Eds.) Dynamical structure Functions in Network Reconstruction (2009)

Presenting a control-theoretic treatment of stoichiometric systems, ... local parametric sensitivity analysis, the two approaches yield identical results. ...

Detailed reference viewed: 116 (4 UL)
See detailControl theory methods for macro models with stochastic micro foundations
Tonita, R. J.; Goncalves, Jorge UL; Lestas, I. C. et al

Scientific Conference (2008)

Detailed reference viewed: 29 (0 UL)
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Peer Reviewed
See detailControllability of transportation networks
Rinaldi, Marco UL; Viti, Francesco UL

Scientific Conference (2018, September)

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See detailControllability of transportation networks
Rinaldi, Marco UL

in Transportation Research. Part B, Methodological (2018), 118

Network-wide traffic control policies determine the optimal values for the different kinds of controllers equipped on a transportation network, with the objective of reducing de- lays and congestion ... [more ▼]

Network-wide traffic control policies determine the optimal values for the different kinds of controllers equipped on a transportation network, with the objective of reducing de- lays and congestion, improving safety and reaching a target Level of Service. While models and algorithms for these problems have been extensively studied in literature, little at- tention has been devoted to investigating whether/how different locations, kinds (pricing controllers, traffic lights, ...) and amounts of controllers in a network affect the overall performance of network-wide schemes. In this work, we adapt the control-theoretical approach of controllability of complex networks to the specific instance of transportation networks, considering both propaga- tion/spillback dynamics and users’ behavior in terms of route choice. Thanks to the newly developed methodology, we then provide exact solutions to the Full Controllability Pric- ing Controller Location Problem for transportation networks. Comparing different pricing controller location policies through two artificial test cases, we empirically demonstrate how indeed the amount and kind of controllers in a network strongly affect the level of performance reachable by network-wide control policies, specifically in terms of Total Cost minimization. [less ▲]

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See detailCoping with turn-taking:Investigating breakdowns in human-robot interaction from a Conversation Analysis (CA) perspective
Arend, Béatrice UL; Sunnen, Patrick UL

in Proceedings: The 8th International Conference on Society and Information Technologies (2017, March)

Detailed reference viewed: 54 (1 UL)
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Peer Reviewed
See detailCorrect biological timing in Arabidopsis requires multiple light-signaling pathways.
Dalchau, N.; Hubbard, K. E.; Robertson, F. C. et al

in Proceedings of the National Academy of Sciences of the United States of America (2010), 107(29), 13171-13176

Circadian oscillators provide rhythmic temporal cues for a range of biological processes in plants and animals, enabling anticipation of the day/night cycle and enhancing fitness-associated traits. We ... [more ▼]

Circadian oscillators provide rhythmic temporal cues for a range of biological processes in plants and animals, enabling anticipation of the day/night cycle and enhancing fitness-associated traits. We have used engineering models to understand the control principles of a plant's response to seasonal variation. We show that the seasonal changes in the timing of circadian outputs require light regulation via feed-forward loops, combining rapid light-signaling pathways with entrained circadian oscillators. Linear time-invariant models of circadian rhythms were computed for 3,503 circadian-regulated genes and for the concentration of cytosolic-free calcium to quantify the magnitude and timing of regulation by circadian oscillators and light-signaling pathways. Bioinformatic and experimental analysis show that rapid light-induced regulation of circadian outputs is associated with seasonal rephasing of the output rhythm. We identify that external coincidence is required for rephasing of multiple output rhythms, and is therefore important in general phase control in addition to specific photoperiod-dependent processes such as flowering and hypocotyl elongation. Our findings uncover a fundamental design principle of circadian regulation, and identify the importance of rapid light-signaling pathways in temporal control. [less ▲]

Detailed reference viewed: 64 (2 UL)
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See detailA cost-effective atomic force microscope for undergraduate control laboratories
Jones, C. N.; Goncalves, Jorge UL

in IEEE Transactions on Education (2010), 53(2), 328-334

This paper presents a simple, cost-effective and robust atomic force microscope (AFM), which has been purposely designed and built for use as a teaching aid in undergraduate controls labs. The guiding ... [more ▼]

This paper presents a simple, cost-effective and robust atomic force microscope (AFM), which has been purposely designed and built for use as a teaching aid in undergraduate controls labs. The guiding design principle is to have all components be open and visible to the students, so the inner functioning of the microscope has been made clear to see. All of the parts but one are off the shelf, and assembly time is generally less than two days, which makes the microscope a robust instrument that is readily handled by the students with little chance of damage. While the scanning resolution is nowhere near that of a commercial instrument, it is more than sufficient to take interesting scans of micrometer-scale objects. A survey of students after their having used the AFM resulted in a generally good response, with 80% agreeing that they had a positive learning experience. [less ▲]

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See detailCrack growth calculations in solder joints based on microstructural phenomena with X-FEM
Menk, Alexander; Bordas, Stéphane UL

in Computational Materials Science (2011), 50(3), 1145-1156

Determining the lifetime of solder joints subjected to thermomechanical loads is crucial to guarantee the quality of electronic devices. The fatigue process is heavily dependent on the microstructure of ... [more ▼]

Determining the lifetime of solder joints subjected to thermomechanical loads is crucial to guarantee the quality of electronic devices. The fatigue process is heavily dependent on the microstructure of the joints. We present a new methodology to determine the lifetime of the joints based on microstructural phenomena. Random microstructures are generated to capture the statistical variety of possible microstructures and crack growth calculations are performed. The extended finite element method is used to solve the structural problem numerically which allows a complete automation of the process. Numerical examples are given and compared to experimental data. [less ▲]

Detailed reference viewed: 56 (0 UL)
See detailCREATIVITY IN TRANSACTIONAL DESIGN PROBLEMS: NON-INTUITIVE FINDINGS OF AN EXPERT STUDY USING SCAMPER
Moreno Grandas, Diana Paola UL; Yang, Maria C.; Hernandez, Alberto A. et al

in INTERNATIONAL DESIGN CONFERENCE - DESIGN 2014 (2014, May)

Designers are currently facing design problems that are not uniquely related to physical systems but transactional as well. Transactional processes (services) have had a steady growth during the last ... [more ▼]

Designers are currently facing design problems that are not uniquely related to physical systems but transactional as well. Transactional processes (services) have had a steady growth during the last three decades and currently add more than 65% of global economic value. This study expands our understanding of designers’ interaction with ideation methods. We investigate a heuristic method known as SCAMPER, focusing on a transactional design problem with a relatively large transactional domain expert sample size (n=60). The study shows, unexpectedly, that the SCAMPER method appears to be both a fixating and de-fixating method (at least for the type of problem explored), where design fixation is not shown to be effectively mitigated by the method; yet, despite this finding, a significantly higher novelty production is achieved when compared to a non-assisted scenario. [less ▲]

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See detailCross-enterprise value stream assessment
Oberhausen, Christof UL; Plapper, Peter UL

in Journal of Advances in Management Research (2017), 14(2), 182-193

Purpose – In most cases, the conventional assessment of value streams is based on key performance indicators (KPIs) like the share of added value, the degree of flow or a comprehensive lead time analysis ... [more ▼]

Purpose – In most cases, the conventional assessment of value streams is based on key performance indicators (KPIs) like the share of added value, the degree of flow or a comprehensive lead time analysis. To evaluate cross-enterprise value streams of manufacturing, business or service processes in detail, a holistic methodology is needed. The paper aims to discuss this issue. Design/methodology/approach – In this research paper, the assessment of value streams within complex cross-company networks is described. After a presentation of relevant KPIs in the fields of value stream management (VSM) and supply chain management (SCM), an approach for a cross-enterprise evaluation of value streams on different levels of detail is shown. In addition, the use of an absolute VSM evaluation, in contrast to a relative VSM assessment, is examined. Findings – Based on a uniform and well-balanced set of KPIs and other VSM and SCM parameters, a performance assessment on different levels of value stream detail is enabled. Further investigations reveal the advantages of a relative compared with an absolute VSM assessment. Research limitations/implications – In addition to a comprehensive overview of existing KPIs for a value stream assessment beyond company borders, a holistic and multi-level VSM approach is presented in this paper. In contrast to existing VSM approaches, the described method allows an evaluation and subsequent improvement of value streams within supply chain networks. Up to now, the presented approach for the assessment of cross-enterprise value streams has only been tested in specific industrial environments. In future, the proposed methodology shall also be validated for other process types like business, service or further manufacturing processes. Practical implications – The described cross-company performance measurement approach shows a high practical relevance for organizations operating in supply chain networks. Due to the integrated use of different VSM parameters, the evaluation of highly interconnected value streams across corporate boundaries is facilitated. By means of a case study, the proposed methodology is validated under real industry conditions and proves its practical applicability. Originality/value – One of the novel features of this research is the extension of the traditional VSM method with respect to a relative evaluation of value streams based on a set of significant KPIs. In addition, the allocation of these KPIs to different value stream layers and categories leads to an innovative approach for a multi-level assessment according to the needs of the specific VSM application, e.g. a more standardized use of VSM in complex supply chain networks. [less ▲]

Detailed reference viewed: 130 (9 UL)
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See detailCutting in real time in corotational elasticity and perspectives on simulating cuts
Courtecuisse, H.; Kerfriden, P.; Bordas, Stéphane UL

Book published by Springer (2013)

We focus here on the simulation of surgical acts of types similar to cutting and needle insertion in soft tissue, in real time (500 Hz), where the scale of the surgical instrument is several orders of ... [more ▼]

We focus here on the simulation of surgical acts of types similar to cutting and needle insertion in soft tissue, in real time (500 Hz), where the scale of the surgical instrument is several orders of magnitude smaller than that of the organ. [less ▲]

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See detailCyber Security and Vulnerability Analysis of Networked Control System subject to False-Data injection
Gerard, Benjamin; Bezzaoucha, Souad UL; Voos, Holger UL et al

in Proceedings of the 2018 American Control Conference (2018, June 27)

In the present paper, the problem of networked control system (NCS) cyber security is considered. The geometric approach is used to evaluate the security and vulnerability level of the controlled system ... [more ▼]

In the present paper, the problem of networked control system (NCS) cyber security is considered. The geometric approach is used to evaluate the security and vulnerability level of the controlled system. The proposed results are about the so-called false data injection attacks and show how imperfectly known disturbances can be used to perform undetectable, or at least stealthy, attacks that can make the NCS vulnerable to attacks from malicious outsiders. A numerical example is given to illustrate the approach. [less ▲]

Detailed reference viewed: 163 (8 UL)
See detailData mining in geographical contexts and texts
Caruso, Geoffrey UL

Presentation (2010)

An increasing number of institutions, acting at different scales and within different sectors, create in-house geographical information systems, e.g. for regional statistics, for land and transport ... [more ▼]

An increasing number of institutions, acting at different scales and within different sectors, create in-house geographical information systems, e.g. for regional statistics, for land and transport management, for local urban planning, etc. In addition, with the advent of new technologies, such as GPS's or web-mapping facilities, the use of such geographical data is being more and more popular and data is made more easily accessible (sometimes even contributed by the end-users). Geographers find themselves in rather data rich environments today (irrespective of homogeneity and quality). Also geographical objects require specific visualization and statistical methods. The application and adaptation of data mining approaches in geographical contexts is an increasingly important research topic. In this lecture we will start from theoretical considerations on data mining in geography, particularly emphasizing what is special with exploratory spatial data analysis. We will then refer to ongoing research related to geographical data mining undertaken at the University of Luxembourg in collaboration with colleagues from other institutions. A first example will refer to a large and homogeneous dataset of all dwellings within a Belgian province. Using graph theory and local spatial statistics, the data is used to identify and categorize urbanisation patterns across scales in an iterative way. A second example will depict an application of 'self-organizing maps' to understand patterns of 'territorial cohesion' in Europe using a rather small and lacunary dataset. The third example will be dedicated to a text-mining application to a rather large corpus of documents related to spatial development in Europe. This work funded under the ESPON (European Spatial Observatory Network) aims at producing a relevant thematic structure to the online regional statistics database of the ESPON network. [less ▲]

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See detailData Science in Europe
Flach, Peter; Spiliopoulou, Myra; Allegrezza, Serge et al

in International Journal of Data Science and Analytics (2018)

Detailed reference viewed: 37 (0 UL)
See detailData Science, Learning by Latent Structures, and Knowledge Discovery
Lausen, Berthold; Krolak-Schwerdt, Sabine UL; Böhmer, Matthias UL

Book published by Springer (2015)

Detailed reference viewed: 143 (12 UL)
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See detailData-driven modelling and simulation: fracture and medical simulations
Bordas, Stéphane UL

Presentation (2018, February 08)

Predicting failure in aircraft structures – simulating fracture across scales and times You could fly every day of your life in a commercial aircraft for twenty thousand years without suffering a fatal ... [more ▼]

Predicting failure in aircraft structures – simulating fracture across scales and times You could fly every day of your life in a commercial aircraft for twenty thousand years without suffering a fatal accident. This extraordinary level of safety is the product of decades of engineering and materials science research. Simultaneously, engineers have strived to produce lighter and stronger aircraft, with increased range and metals have thus been gradually replaced by lighter advanced composite materials which take up more than half of the structural weight of today's most advanced aircraft. Such progress has been largely enabled by modeling and simulation of materials and structures, which have revolutionized design by enabling engineers to investigate virtually various design strategies. This presentation will focus on the challenges which have been posed, are posed, and will be posed to such modeling and simulation tools in the strive to predict the durability of lighter, stronger, longer-ranging and more reliable aircraft. [less ▲]

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See detailDeadzone-Quadratic Penalty Function for Predictive Extended Cruise Control with Experimental Validation
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in ROBOT 2017: Third Iberian Robotics Conference, Sevilla, Spain 22-24 November 2017 (2017, November)

Battery Electric Vehicles have high potentials for the modern transportations, however, they are facing limited cruising range. To address this limitation, we present a semi-autonomous ecological driver ... [more ▼]

Battery Electric Vehicles have high potentials for the modern transportations, however, they are facing limited cruising range. To address this limitation, we present a semi-autonomous ecological driver assistance system to regulate the velocity with energy-efficient techniques. The main contribution of this paper is the design of a real-time nonlinear receding horizon optimal controller to plan the online cost-effective cruising velocity. Instead of conventional L2-norms, a deadzone-quadratic penalty function for the nonlinear model predictive controller is proposed. Obtained field experimental results demonstrate the effectiveness of the proposed method for a semi-autonomous electric vehicle in terms of real-time energy-efficient velocity regulation and constraints satisfaction. [less ▲]

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See detailDealing with interfaces in partitioned model order reduction for application to nonlinear problems
Goury, Olivier; Kerfriden, Pierre; Bordas, Stéphane UL

Scientific Conference (2013)

We propose a reduced order modelling technique based on a partitioning of the domain of study in the context of para- metric nonlinear problems. A formulation of the reduction of the displacement and of ... [more ▼]

We propose a reduced order modelling technique based on a partitioning of the domain of study in the context of para- metric nonlinear problems. A formulation of the reduction of the displacement and of the interface tractions linking subdomains to each others will be performed in a FETI context. [less ▲]

Detailed reference viewed: 257 (4 UL)