Search results for " Mach"
showing 10 items of 1388 documents
Control of hysteretic instability in rotating machinery by elastic suspension systems subject to dry and viscous friction
2010
Abstract Most of the undesired whirling motions of rotating machines can be efficiently reduced by supporting journal boxes elastically and controlling their movement by viscous dampers or by dry friction surfaces normal to the shaft axis, which rub against the frame. In the case of dry dampers, resonance ranges of the floating support configuration can be easily cut off by planning a motionless adhesive state of the friction surfaces. On the contrary, the dry friction contact must change automatically into sliding conditions when the fixed support resonances are to be feared. Moreover, the whirl amplitude can be restrained throughout the speed range by a proper choice of the suspension-to-…
Virtual Synchronous Machine Control of RES Plants in Isolated Power Systems
2022
Because of the increase in renewable energy sources (RESs) share, new control strategies of isolated power systems have been developed to improve the frequency and voltage stability of inverter-interfaced RESs. A voltage source converter (VSC) with a virtual synchronous machine (VSM) is among the most promising control schemes. This paper demonstrates how VSM control of inverter-interfaced RES can be efficiently used to improve the dynamic stability in small isolated power systems. In the proposed analysis, the RESs of a Mediterranean island are assumed interfaced to the grid by VSCs with a swing controller and a vector-current controller (VCC) with two different options for the reference c…
On Unsupervised Methods for Medical Image Segmentation: Investigating Classic Approaches in Breast Cancer DCE-MRI
2021
Unsupervised segmentation techniques, which do not require labeled data for training and can be more easily integrated into the clinical routine, represent a valid solution especially from a clinical feasibility perspective. Indeed, large-scale annotated datasets are not always available, undermining their immediate implementation and use in the clinic. Breast cancer is the most common cause of cancer death in women worldwide. In this study, breast lesion delineation in Dynamic Contrast Enhanced MRI (DCE-MRI) series was addressed by means of four popular unsupervised segmentation approaches: Split-and-Merge combined with Region Growing (SMRG), k-means, Fuzzy C-Means (FCM), and spatial FCM (…
Robustness, Stability, and Fidelity of Explanations for a Deep Skin Cancer Classification Model
2022
Skin cancer is one of the most prevalent of all cancers. Because of its being widespread and externally observable, there is a potential that machine learning models integrated into artificial intelligence systems will allow self-screening and automatic analysis in the future. Especially, the recent success of various deep machine learning models shows promise that, in the future, patients could self-analyse their external signs of skin cancer by uploading pictures of these signs to an artificial intelligence system, which runs such a deep learning model and returns the classification results. However, both patients and dermatologists, who might use such a system to aid their work, need to …
Optimization of Cultural Heritage Virtual Environments for Gaming Applications
2020
Serious games are games with a purpose beyond entertainment and are widely acknowledged as fruitful tools for learning and developing skills across multiple domains, including educational enhancement. In the last few years, the world of serious games has widely increased. The use of these types of games can aid in classrooms to not only help the students learn concepts but also to improve their motivation to do so. However, designing games necessitates very specialized personnel and the process can often be costly and slow. The adaptions of the design to the implantation phase are also difficult and the process needs more focus. The challenge of this study was to create a game within the co…
La sufixació apreciativa del català: creacions lèxiques i implicacions morfològiques
2015
Resum: La situació de la derivació apreciativa dins la morfologia és excepcional, perquè la informació limitada que contenen, en general, les gramàtiques i els diccionaris sobre els apreciatius així com l’ús habitual d’aquestes formes en contextos familiars i informals fan que la creativitat dels parlants no es vegi limitada per normatives i que, per tant, aflorin solucions imaginatives, que, tot i la variació existent, segueixen uns condicionaments gramaticals clars. L’objectiu d’aquest treball és aportar noves dades en aquest camp a partir de formes recollides en corpus tradicionals i per internet, amb una doble finalitat: d’una banda, aprofundir en les particularitats morfològiques de la…
2020
The scientific and practical fields-especially high-performance sports-increasingly request a stronger focus be placed on individual athletes in human movement science research. Machine learning methods have shown efficacy in this context by identifying the unique movement patterns of individuals and distinguishing their intra-individual changes over time. The objective of this investigation is to analyze biomechanically described movement patterns during the fatigue-related accumulation process within a single training session of a high number of repeated executions of a ballistic sports movement-specifically, the frontal foot kick (mae-geri) in karate-in expert athletes. The two leading r…
Concept of virtual machine based high resolution display wall
2014
This paper presents the scalability and hardware dependency problems found in existing solutions in the high resolution display wall domain and proposes a new solution. Authors propose hosting the system that provides the visual content for the display wall inside a virtual machine. In such way any needed configuration of displays and resolutions can be applied to the graphics processing unit simulated by the virtualization system. The frame buffer content of the virtual graphics processing unit is then split, encoded with H.264 and sent over gigabit Ethernet as an RTP stream to the display wall. The display wall is driven by Raspberry Pi embedded devices that receive the stream, decode it …
A genetic integrated fuzzy classifier
2005
This paper introduces a new classifier, that is based on fuzzy-integration schemes controlled by a genetic optimisation procedure. Two different types of integration are proposed here, and are validated by experiments on real data sets of biological cells. The performance of our classifier is tested against a feed-forward neural network and a Support Vector Machine. Results show the good performance and robustness of the integrated classifier strategies.
No-Reference 3D Mesh Quality Assessment Based on Dihedral Angles Model and Support Vector Regression
2016
International audience; 3D meshes are subject to various visual distortions during their transmission and geometrical processing. Several works have tried to evaluate the visual quality using either full reference or reduced reference approaches. However, these approaches require the presence of the reference mesh which is not available in such practical situations. In this paper, the main contribution lies in the design of a computational method to automatically predict the perceived mesh quality without reference and without knowing beforehand the distortion type. Following the no-reference (NR) quality assessment principle, the proposed method focuses only on the distorted mesh. Specific…