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See detailExperimental and Numerical Investigation on Postcracking Behavior of Steel Fiber Reinforced Concrete
Michels, Julien; Christen, Christen; Waldmann, Danièle UL

in Engineering Fracture Mechanics (2012) (2012)

Detailed reference viewed: 124 (9 UL)
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See detailExperimental approach to the aerodynamic effects produced in multirotors flying close to obstacles
Sanchez Cuevas, Pedro Jesus UL; Heredia, Guillermo; Ollero, Anibal

in Experimental approach to the aerodynamic effects produced in multirotors flying close to obstacles (2017, November 12)

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See detailAn experimental approach to the dynamics of nuclear polarisation
van den Brandt, B.; Glättli, H.; Grillo, I. et al

in Nuclear Instruments & Methods in Physics Research Section A (2004), 526

In the past 3 years a series of experiments have shed new light on the mechanism of dynamic nuclear polarisation (DNP). Time-resolved polarised small-angle neutron scattering and nuclear magnetic ... [more ▼]

In the past 3 years a series of experiments have shed new light on the mechanism of dynamic nuclear polarisation (DNP). Time-resolved polarised small-angle neutron scattering and nuclear magnetic resonance have been used simultaneously to study the nuclear polarisation build-up around paramagnetic centres during DNP. This approach, which aims at visualising the nuclear polarisation process on a microscopic scale, shall be exemplified and the experimental techniques used described in some detail. [less ▲]

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See detailExperimental characterization of the effects of acute stresslike doses of hydrocortisone in human neurogenic hyperlagesia models
Michaux, Gilles; Magerl, Walter; Anton, Fernand UL et al

in Pain (2012), 153(2), 420-428

Detailed reference viewed: 43 (0 UL)
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See detailAn experimental comparison of security markets: call-auction vs. double-auction
Neugebauer, Tibor UL

Scientific Conference (2012)

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See detailAn Experimental Comparison of Two Exchange Economies: Long-Lived Asset Versus Short-Lived Asset
Neugebauer, Tibor UL; Carbone, Enrica; D. Hey, John

in Management Science (2021)

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See detailExperimental design trade-offs for gene regulatory network inference: an in silico study of the yeast Saccharomyces cerevisiae cell cycle
Markdahl, Johan UL; Colombo, Nicolo UL; Thunberg, Johan UL et al

in Proceedings of the 56th IEEE Conference on Decision and Control (2017, December)

Time-series of high throughput gene sequencing data intended for gene regulatory network (GRN) inference are often short due to the high costs of sampling cell systems. Moreover, experimentalists lack a ... [more ▼]

Time-series of high throughput gene sequencing data intended for gene regulatory network (GRN) inference are often short due to the high costs of sampling cell systems. Moreover, experimentalists lack a set of quantitative guidelines that prescribe the minimal number of samples required to infer a reliable GRN model. We study the temporal resolution of data vs.quality of GRN inference in order to ultimately overcome this deficit. The evolution of a Markovian jump process model for the Ras/cAMP/PKA pathway of proteins and metabolites in the G1 phase of the Saccharomyces cerevisiae cell cycle is sampled at a number of different rates. For each time-series we infer a linear regression model of the GRN using the LASSO method. The inferred network topology is evaluated in terms of the area under the precision-recall curve (AUPR). By plotting the AUPR against the number of samples, we show that the trade-off has a, roughly speaking, sigmoid shape. An optimal number of samples corresponds to values on the ridge of the sigmoid. [less ▲]

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See detailExperimental Evaluation of a Team of Multiple Unmanned Aerial Vehicles for Cooperative Construction
Real, Fran; Castaño, Angel; Torres-Gonzalez, Arturo et al

in IEEE Access (2021)

This article presents a team of multiple Unmanned Aerial Vehicles (UAVs) to perform cooperative missions for autonomous construction. In particular, the UAVs have to build a wall made of bricks that need ... [more ▼]

This article presents a team of multiple Unmanned Aerial Vehicles (UAVs) to perform cooperative missions for autonomous construction. In particular, the UAVs have to build a wall made of bricks that need to be picked and transported from different locations. First, we propose a novel architecture for multi-robot systems operating in outdoor and unstructured environments, where robustness and reliability play a key role. Then, we describe the design of our aerial platforms and grasping mechanisms to pick, transport and place bricks. The system was particularly developed for the Mohamed Bin Zayed International Robotics Challenge (MBZIRC), where Challenge 2 consisted of building a wall cooperatively with multiple UAVs. However, our approach is more general and extensible to other multi-UAV applications involving physical interaction, like package delivery. We present not only our results in the final stage of MBZIRC, but also our simulations and field experiments throughout the previous months to the competition, where we tuned our system and assessed its performance. [less ▲]

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See detailExperimental Evaluation of a Tool for Change Impact Prediction in Requirements Models: Design, Results, and Lessons Learned
Göknil, Arda UL; van Domburg, Roderick; Kurtev, Ivan et al

in The Fourth International Model-Driven Requirements Engineering (MoDRE) workshop (2014)

There are commercial tools like IBM Rational RequisitePro and DOORS that support semi-automatic change impact analysis for requirements. These tools capture the requirements relations and allow tracing ... [more ▼]

There are commercial tools like IBM Rational RequisitePro and DOORS that support semi-automatic change impact analysis for requirements. These tools capture the requirements relations and allow tracing the paths they form. In most of these tools, relation types do not say anything about the meaning of the relations except the direction. When a change is introduced to a requirement, the requirements engineer analyzes the impact of the change in related requirements. In case semantic information is missing to determine precisely how requirements are related to each other, the requirements engineer generally has to assume the worst case dependencies based on the available syntactic information only. We developed a tool that uses formal semantics of requirements relations to support change impact analysis and prediction in requirements models. The tool TRIC (Tool for Requirements Inferencing and Consistency checking) works on models that explicitly represent requirements and the relations among them with their formal semantics. In this paper we report on the evaluation of how TRIC improves the quality of change impact predictions. A quasi-experiment is systematically designed and executed to empirically validate the impact of TRIC. We conduct the quasi-experiment with 21 master’s degree students predicting change impact for five change scenarios in a real software requirements specification. The participants are assigned with Microsoft Excel, IBM RequisitePro or TRIC to perform change impact prediction for the change scenarios. It is hypothesized that using TRIC would positively impact the quality of change impact predictions. Two formal hypotheses are developed. As a result of the experiment, we are not able to reject the null hypotheses, and thus we are not able to show experimentally the effectiveness of our tool. In the paper we discuss reasons for the failure to reject the null hypotheses in the experiment. [less ▲]

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See detailExperimental Evaluation of Floating Car Data Collection Protocols in Vehicular Networks
Turcanu, Ion UL; Adamsky, Florian; Engel, Thomas UL

in IEEE 90th Vehicular Technology Conference (VTC2019-Fall) (2019)

The main objectives of the Intelligent Transportation Systems (ITS) vision is to improve road safety, traffic management, and mobility by enabling cooperative communication among participants. This vision ... [more ▼]

The main objectives of the Intelligent Transportation Systems (ITS) vision is to improve road safety, traffic management, and mobility by enabling cooperative communication among participants. This vision requires the knowledge of the current state of the road traffic, which can be obtained by collecting Floating Car Data (FCD) information using Dedicated Short-Range Communication (DSRC) based on the IEEE 802.11p standard. Most of the existing FCD collection protocols have been evaluated via simulations and mathematical models, while the real-world implications have not been thoroughly investigated. This paper presents an open-source implementation of two state-of-the-art FCD collection algorithms, namely BASELINE and DISCOVER. These algorithms are implemented in an open-source vehicular prototyping platform and validated in a real-world experimental setup. [less ▲]

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See detailExperimental evaluation of RF waveform designs for Wireless Power Transfer using Software Defined Radio
Gautam, Sumit UL; Kumar, Sumit UL; Chatzinotas, Symeon UL et al

in IEEE Access (2021), 9

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest ... [more ▼]

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest in the field of wireless power transfer (WPT) using the RF range of the electromagnetic (EM) spectrum. In this paper, we experimentally investigate the aspect of real-time energy harvesting (EH) via different types of waveform designs such as orthogonal frequency division multiplexing (OFDM), square, triangular, sinusoidal, and sawtooth. We make use of a Software Defined Radio (SDR) and a Powercast P21XXCSR-EVB EH module to carry out the experiments on a practical device to assess performance. Specifically, we are interested in obtaining some insights based on the comparison between the aforementioned waveform designs from the perspectives of the separation distance between the USRP and P21XXCSR-EVB EH module, and power emission via USRP. In this vein, we perform additional subsequent experiments after reporting the practical effectiveness of the OFDM waveform, which also follows our intuitive analysis. Correspondingly, we study the effect on WPT with variable USRP transmit power, the separation distance between the USRP and EH antennas, number of OFDM sub-carriers, and multipath setting. As an application of OFDM, the effectiveness of fifth generation-new radio (5G-NR) and long-term evolution (LTE) waveforms are also tested for the WPT mechanism. The demonstration of the EH is provided in terms of the above-mentioned investigation metrics while seeking the best waveform to support WPT. [less ▲]

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See detailExperimental evaluation of RF waveform designs for Wireless Power Transfer using Software Defined Radio
Gautam, Sumit UL; Kumar, Sumit UL; Chatzinotas, Symeon UL et al

in IEEE Access (2021), 9

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest ... [more ▼]

The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest in the field of wireless power transfer (WPT) using the RF range of the electromagnetic (EM) spectrum. In this paper, we experimentally investigate the aspect of real-time energy harvesting (EH) via different types of waveform designs such as orthogonal frequency division multiplexing (OFDM), square, triangular, sinusoidal, and sawtooth. We make use of a Software Defined Radio (SDR) and a Powercast P21XXCSR-EVB EH module to carry out the experiments on a practical device to assess performance. Specifically, we are interested in obtaining some insights based on the comparison between the aforementioned waveform designs from the perspectives of the separation distance between the USRP and P21XXCSR-EVB EH module, and power emission via USRP. In this vein, we perform additional subsequent experiments after reporting the practical effectiveness of the OFDM waveform, which also follows our intuitive analysis. Correspondingly, we study the effect on WPT with variable USRP transmit power, the separation distance between the USRP and EH antennas, number of OFDM sub-carriers, and multipath setting. As an application of OFDM, the effectiveness of fifth generation-new radio (5G-NR) and long-term evolution (LTE) waveforms are also tested for the WPT mechanism. The demonstration of the EH is provided in terms of the above-mentioned investigation metrics while seeking the best waveform to support WPT. [less ▲]

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See detailExperimental Finance
Neugebauer, Tibor UL

Presentation (2015)

Detailed reference viewed: 49 (0 UL)
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See detailExperimental identification of a lattice model for woven fabrics: Application to electronic textile
Beex, Lars UL; Verberne, Cyriel; Peerlings, Ron

in Composites. Part A, Applied Science and Manufacturing (2013), 48

Lattice models employing trusses and beams are suitable to investigate the mechanical behavior of woven fabrics. The discrete features of the mesostructures of woven fabrics are naturally incorporated by ... [more ▼]

Lattice models employing trusses and beams are suitable to investigate the mechanical behavior of woven fabrics. The discrete features of the mesostructures of woven fabrics are naturally incorporated by the discrete elements of lattice models. In this paper, a lattice model for woven materials is adopted which consists of a network of trusses in warp and weft direction, which represent the response of the yarns. Additional diagonal trusses are included that provide a resistance against relative rotation of the yarns. The parameters of these families of discrete elements can be separately identified from tensile experiments in three in-plane directions which correspond with the orientations of the discrete elements. The lattice model and the identification approach are applied to electronic textile. This is a fabric in which conductive wires are incorporated to allow the embedment of electronic components such as light-emitting diodes. The model parameters are established based on tensile tests on samples of the electronic textile. A comparison between the experimental results of an out-of-plane punch test and the simulation results shows that the lattice model and its characterization procedure are accurate until extensive biaxial tensile deformation occurs. [less ▲]

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See detailExperimental induction of suffering: why suffering is not the same as unpleasantness
Brunner, Michael; Löffler, Martin; Kamping, Sandra et al

Scientific Conference (2014, October 10)

Detailed reference viewed: 200 (1 UL)
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See detailExperimental investigations and numerical modeling of point-fitted glass panes
Tibolt, Mike UL; Odenbreit, Christoph UL; Hechler, Oliver UL

in ICSA2013 - Conference book (2013, July)

The highest transparency of façades is to be obtained by the use of point-fitted glass units. To comply with the demand for energy efficiency the use of insulating glass units is required. However ... [more ▼]

The highest transparency of façades is to be obtained by the use of point-fitted glass units. To comply with the demand for energy efficiency the use of insulating glass units is required. However, insufficient knowledge is present for point fittings in insulating glass which is a drawback of this kind of construction. Therefore research has been carried out to extend an existing design-method, the SLG-method, to insulating glass. In this paper, first, experimental investigations in point-fitted single glass units and the results are presented. Secondly, a numerical model is introduced which has been calibrated to this test data. This model will subsequently be extended to other geometries and the stress peaks at the borehole as well as the size of the local area for the SLG-method will be determined. Therefore this paper presents the preparation process for the application of the SLG-method for insulation glass units. [less ▲]

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See detailExperimental investigations on semi-continuous encased composite joints
Duarte Da Costa, Job UL; Obiala, Renata UL; Odenbreit, Christoph UL

in Eurosteel 2017 (2017, September 13)

The benefits brought to composite construction by the use of semi-continuous joints are well recognised and confirmed by the significant amount of research which has been performed in this area. It has ... [more ▼]

The benefits brought to composite construction by the use of semi-continuous joints are well recognised and confirmed by the significant amount of research which has been performed in this area. It has been analytically proven that at serviceability limit state (SLS) the performance of composite beams benefits from the use of semi-continuous composite joints [1]. At ultimate limit state (ULS) it is of common knowledge that the use of semi-continuous composite joints is only judicious in combination with the plastic hinge theory, which requires the verification of the rotation capacity of the joint. Despite all the effort done in this area, a concise and well-defined method to determine the rotation capacity of composite joints is lacking. Hence, a research programme with a large experimental part has been designed to investigate the behaviour of the connection between a column and a composite slim-floor beam subjected to a negative bending moment. It is the first time that the rotation capacity of an encased composite joint is analysed. The experimental campaign, presented in here, aims at determining the influence of each joint component on the rotation capacity of composite joints. Three test series have been performed; on boltless beam-to-column connections using variable longitudinal reinforcement ratio and bar diameter of the slab, on a bare bolted end-plate steel connection without reinforced concrete slab and finally on the encased composite joint with the complete bolted end-plate connection. This paper presents a detailed description of the tested specimen, shows the main results of the experimental investigations and gives an outlook on future work regarding this research project. The final goal of the research project is to develop a comprehensive methodology to predict the rotation capacity for traditional and slim-floor type of composite beams. [less ▲]

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See detailExperimental Lifetime Investigation of Series Connected Li-ion Cells at Different Operation Strategies
Brühl, Manuel UL; Sauer, Dirk Uwe; Hadji-Minaglou, Jean-Régis UL

Poster (2016, April 26)

Battery systems consisting of serially connected cells suffer from uneven cell degradation. This phenomenon can be observed, even if li-ion cells of the same type and batch are cycled in a fixed voltage ... [more ▼]

Battery systems consisting of serially connected cells suffer from uneven cell degradation. This phenomenon can be observed, even if li-ion cells of the same type and batch are cycled in a fixed voltage window at the same temperature. The uneven cell degradation has a significant impact on the usable capacity of a battery system as the system capacity is limited by the capacity of the weakest cell. This issue reduces the battery lifetime and increases the costs. In a former work, li-ion cells were cycled individually and the different cell degradation could be observed significantly. In this work, aging tests are conducted with cells in series connected conditions to investigate the uneven cell degradation behavior. Cyclization of series connected cells could lead to a higher spread of cell degradation as weaker cells are deeper cycled. Three aging tests, each consisting of eight li-ion cells are conducted in this work. The eight cells of each test are cycled with the same current to investigate the aging behavior under comparable conditions as in a series connection. The first test is conducted to investigate the aging behavior of a conventional system with series connected cells and passive balancing. In the second and third test, the uneven cell degradation is actively compensated with the operation strategy of the balancing circuit. In the second test the voltage window are changed with respect to the cell’s state of health. In the third test the cell current of each cell is changed with respect to the cell’s state of health. Preliminary results show that cells in the first test suffer a bigger capacity diversion over time than cells in the second and third test. Such operation strategies could be implemented in real systems to reduce the different cell degradation and to prolong the systems lifetime. Further analysis and conclusions will be given on the conference poster. [less ▲]

Detailed reference viewed: 147 (8 UL)
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See detailExperimental Media Archaeology: A Plea for New Directions
Fickers, Andreas UL; van den Oever, Annie

in Van den Oever, Annie (Ed.) Techné / Technology. Researching Cinema and Media Technologies - Their development, Use, and Impact (2013)

Detailed reference viewed: 455 (12 UL)
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See detailExperimental observation of magnetic poles inside bulk magnets via q \neq 0 Fourier modes of magnetostatic field
Perigo, Elio Alberto UL; Gilbert, E.P.; Metlov, K.L. et al

in New Journal of Physics (2014), 16

Detailed reference viewed: 121 (2 UL)