197,484 research outputs found
The results of the Delft Systematic Deadrise Series
No full textIn the present paper the development of the Delft Systematic Deadrise Series (DSDS) is described. The DSDS has been under development for decades by now and consists of a large family of systematically varied hard chine planing monohulls, based on the original research by Clement and Blount, which have all been tested in the same speed range, changing the same parameters and using the same experimental set up. The rationale behind the DSDS is highlighted. The DSDS contains up to now some 24 different models in 350 different conditions all tested in the same speed range between Fn∇ = 0.75 and Fn∇ = 3.0. Recently there has been a new extension to the DSDS with the inclusion of more measurements on hulls with twisted bottom and rocker in the aft ship. These results are presented in this paper.In addition detailed access is facilitated to all the hull geometries used into the DSDS and to all the raw measurement data obtained during the tests by means of free access to a dedicated website.Ship Hydromechanics and Structure
fast-histogram v0.7: fast simple 1D and 2D histograms in Python
No full textSometimes you just want to compute simple 1D or 2D histograms with regular bins. Fast. No nonsense. Numpy’s histogram functions are versatile, and can handle for example non-regular binning, but this versatility comes at the expense of performance.
The fast-histogram mini-package aims to provide simple and fast histogram functions for regular bins that don’t compromise on performance. It doesn’t do anything complicated - it just implements a simple histogram algorithm in C and keeps it simple. The aim is to have functions that are fast but also robust and reliable. The result is a 1D histogram function here that is 7-15x faster than numpy.histogram, and a 2D histogram function that is 20-25x faster than numpy.histogram2d.</p
Experimental and numerical investigation on the heel and drift induced hydrodynamical loads of a high speed craft
No full textIn order to provide an insight into the manoeuvring of high speed crafts, an experimental study was undertaken at the towing tank of Delft University of Technology, using a rescue vessel of the Royal Netherlands Sea Rescue Institution (KNRM).Ship Hydromechanics and Structure
Discrete Darboux based fast inverse nonlinear Fourier transform algorithm for multi-solitons
No full textA fast algorithm for constructing multi-solitons with linear complexity in the number of samples and eigenvalues is introduced. The algorithm is shown to be significantly faster than the conventional Darboux transform in a numerical example, with acceptable error.Accepted Author ManuscriptTeam Raf Van de PlasTeam Sander Wahl
Fast interfaces
No full textLi4Ti5O12 is a commonly used negative electrode material, but the origin of its fast rate capability has puzzled scientists for decades. Now, a facile Li-ion transport route featuring metastable intermediates is revealed to rationalize the fast-charging kinetics.Accepted Author ManuscriptRID/TS/Instrumenten groepRST/Storage of Electrochemical Energ
FAST-EDI
No full text# Fast Event-based Double Integral for Real-time Robotics (Academic Use Only)
## [Paper](https://arxiv.org/abs/2305.05925) | [Video: Youtube](https://www.youtube.com/watch?v=xzrHNA97wls) | [Video: Bilibili](https://www.bilibili.com/video/BV1qL411X7hc/?share_source=copy_web&vd_source=2483c9488f1bd3f3478cf69bfca4d49e)
Motion deblurring is a critical ill-posed problem that is important in many vision-based robotics applications. The recently proposed event-based double integral (EDI) provides a theoretical framework for solving the deblurring problem with the event camera and generating clear images at high frame-rate. However, the original EDI is mainly designed for offline computation and does not support real-time requirement in many robotics applications. In this paper, we propose the fast EDI, an efficient implementation of EDI that can achieve real-time online computation on single-core CPU devices, which is common for physical robotic platforms used in practice. In experiments, our method can handle event rates at as high as 13 million event per second in a wide variety of challenging lighting conditions. Its benefit has been demonstrated on multiple downstream real-time applications, including localization, visual tag detection, and feature matching.
## Understanding the hardware bias of event camera
[Tutorial of the bias](https://gitlab.com/inivation/inivation-docs/blob/master/Advanced configurations/User_guide_-_Biasing.md)
## Checking the hardware bias using the jAER
One can use the jAER project to get a roughly estimated contrast from the bias currents that are estimated to be generated by the on-chip bias generator bias current ratios:[jAER homepage](https://github.com/SensorsINI/jaer)
Discussion regarding the bias estimation:[discussion](https://groups.google.com/g/davis-users/c/68gp0zxTMUk/m/SpweyJKrDgAJ)
and the physical model that build to estimate the threshold:[Paper](https://ieeexplore.ieee.org/document/7962235/)
## Usage
Test env:
```
ubuntu 18.04
dv-runtime 1.6.1
dv-gui 1.6.0
```
1. download the DV and install it following the tutorial [DV install guide](https://inivation.gitlab.io/dv/dv-docs/docs/getting-started.html)
2. download the fast EDI code
```
git clone https://github.com/eleboss/fast_EDI
```
3. compile the fast EDI module
```
cd ./dv-module/fast-edi
cmake ./
make
```
then you will see the `fedi_FEDI.so`, this is the file you need to add to the dv-gui.
4. configure the DV-GUI search path
```
dv-gui
```
find the `structure - add modules - modify module search path - add path` (this path leads to `fedi_FEDI.so`, for me is `/home/eleboss/Documents/fast_EDI/dv-module/fast-edi`). Then you can add the fast edi modules to the dv-gui and wires it in this way:
5. download the test data [dataset](www.google.com), and play it.
Performance tips: You can tune the contrast or use the jAER to estimate, or use EDI to optimize an accurate contrast.
## Citation
```
@article{lin2023fast,
title={Fast Event-based Double Integral for Real-time Robotics},
author={Lin, Shijie and Zhang, Yingqiang and Huang, Dongyue and Zhou, Bin and Luo, Xiaowei and Pan, Jia},
booktitle={international conference on robotics and automation (ICRA)},
year={2023},
organization={IEEE}
}
```
</p
'No they're not digital natives and they're not addicted': an essay critiquing contestable labels
No full textReducing complexity is often our focus when we explain new phenomena. However when we label things in simplistic ways, we may be in fact causing harm, in fact performing symbolic violence (Bourdieu 1998) by using and promoting essences of the phenomena in question. This essay gives examples of these simplistic, inappropriate categories that essentialize people into inflexible boxes, and argues that labeling is a simplistic practice, which gives us (mis)certainty. To me, there is a need for nuanced understandings of phenomena versus reductionist suppositions. We need insight rather than generalizations and essentializations. Many (mis)assumptions are based on a lack of evidence. This short essay argues against the constant complexity reduction apparent in popular (and to a certain extent academic) discourse. It highlights the ‘good’ of a society shaped by and shaping the Internet. It draws together the two labels of digital natives and Internet addiction to provide examples of how symbolic violence is being inflicted
An alternating frequency-time harmonic balance method for fast-slow dynamical systems
No full textThe Alternating Frequency-Time (AFT) Harmonic Balance method has been widely applied in the analysis of non-linear mechanical systems under periodic excitation. Customarily, a periodic displacement is considered as ansatz in a harmonic balance analysis. In the present work, a deviation from the latter ansatz is realized and the periodicity is assumed in the velocity, leading to a linear term in the displacement of the system. The latter approach aims to facilitate the analysis of a certain class of systems, which are characterized by a fast periodic motion and a slow non-periodic motion. The motivation of this study originates in the area of offshore engineering and more specifically in the topic of monopile installation. During vibratory pile installation, the pile is forced into the soil under the combined action of a periodic excitation at the pile top and the self-weight of the pile and the vibratory device. As a result, the pile simultaneously penetrates into the soil as a rigid body (slow motion) and vibrates in the driving frequency and its super-harmonics both as a rigid and a flexible body (fast motion). In this study, the AFT harmonic balance with the ansatz of periodic velocity is implemented in different problem cases. A set of non-linear mechanical systems are analysed, ranging from a single-degree-of-freedom to a continuum, to showcase the potential application of the method and to verify its accuracy.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Dynamics of StructuresOffshore EngineeringEngineering Structure
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