scholarly journals Transient Process at Atmospheric Discharge into the Landline and the Appearance of an Electric Arc in the Switch

Author(s):  
Slobodan N. Bjelić ◽  
◽  
Filip N. Marković ◽  
Nenad A. Marković

This document proposes a model of the process of atmospheric discharge of overhead lines followed by an electric arc. The intensity of atmospheric discharges, followed by electric arc and destruction, is determined by the difference in potential and current. Such a structure and form of discharge make it difficult to analyze the transient process and obtain adequate solutions. That is why the model of the transient process in the electric arc of the switch under the conditions of interruption of the AC circuit is specially analyzed. Simple equivalent schemes for the analysis of phenomena with given values of linear parameters are presented, which are very simple to apply. All influential parameters by which the overvoltage values in the model can be estimated were also taken into account. The evaluation of the proposed model was performed using the adapted MATLAB program psbsurlightcuurent for atmospheric electrical discharge, which contains a high frequency current source. The verified simulation method was used to verify the results as part of a method derived from artificial intelligence algorithms. The process simulation program, the obtained voltage and current diagrams confirm the application of the simulation algorithm model.

Author(s):  
Koosha Choobdari Omran ◽  
Ali Mosallanejad

Purpose Double rotor induction machine (DRIM) is a particular type of induction machine (IM) that has been introduced to improve the parameters of the conventional IM. The purpose of this study is to propose a dynamic model of the DRIM under saturated and unsaturated conditions by using the equations obtained in this paper. Also, skin and temperature effects are considered in this model. Design/methodology/approach First, the DRIM structure and its performance will be briefly reviewed. Then, to realize the DRIM model, the mathematical equations of the electrical and mechanical part of the DRIM will be presented by state equations in the q-d axis by using the Park transformation. In this paper, the magnetizing fluxes saturation is included in the DRIM model by considering the difference between the amplitudes of the unsaturated and saturated magnetizing fluxes. The skin and temperature effects are also considered in this model by correcting the rotor and stator resistances values during operation. Findings To evaluate the effects of the saturation and skin effects on DRIM performance and validate the model, the machine is simulated with/without consideration of saturation and skin effects by the proposed model. Then, the results, including torque, speed, stator and rotor currents, active and reactive power, efficiency, power factor and torque-speed characteristic, are compared. In addition, the performance of the DRIM has been investigated at different speed conditions and load variations. The proposed model is developed in Matlab/Simulink for the sake of validation. Originality/value This paper presents an understandable model of DRIM with and without saturation, which can be used to analyze the steady-state and transient behavior of the motor in different situations.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Wen-Jun Li ◽  
Qiang Dong ◽  
Yan Fu

As the rapid development of mobile Internet and smart devices, more and more online content providers begin to collect the preferences of their customers through various apps on mobile devices. These preferences could be largely reflected by the ratings on the online items with explicit scores. Both of positive and negative ratings are helpful for recommender systems to provide relevant items to a target user. Based on the empirical analysis of three real-world movie-rating data sets, we observe that users’ rating criterions change over time, and past positive and negative ratings have different influences on users’ future preferences. Given this, we propose a recommendation model on a session-based temporal graph, considering the difference of long- and short-term preferences, and the different temporal effect of positive and negative ratings. The extensive experiment results validate the significant accuracy improvement of our proposed model compared with the state-of-the-art methods.


Author(s):  
P. Vijayalakshmi ◽  
K. Muthumanickam ◽  
G. Karthik ◽  
S. Sakthivel

Adenomyosis is an abnormality in the uterine wall of women that adversely affects their normal life style. If not treated properly, it may lead to severe health issues. The symptoms of adenomyosis are identified from MRI images. It is a gynaecological disease that may lead to infertility. The presence of red dots in the uterus is the major symptom of adenomyosis. The difference in the extent of these red dots extracted from MRI images shows how significant the deviation from normality is. Thus, we proposed an entroxon-based bio-inspired intelligent water drop back-propagation neural network (BIWDNN) model to discover the probability of infertility being caused by adenomyosis and endometriosis. First, vital features from the images are extracted and segmented, and then they are classified using the fuzzy C-means clustering algorithm. The extracted features are then attributed and compared with a normal person’s extracted attributes. The proposed BIWDNN model is evaluated using training and testing datasets and the predictions are estimated using the testing dataset. The proposed model produces an improved diagnostic precision rate on infertility.


2020 ◽  
Vol 12 (11) ◽  
pp. 1746
Author(s):  
Salman Ahmadi ◽  
Saeid Homayouni

In this paper, we propose a novel approach based on the active contours model for change detection from synthetic aperture radar (SAR) images. In order to increase the accuracy of the proposed approach, a new operator was introduced to generate a difference image from the before and after change images. Then, a new model of active contours was developed for accurately detecting changed regions from the difference image. The proposed model extracts the changed areas as a target feature from the difference image based on training data from changed and unchanged regions. In this research, we used the Otsu histogram thresholding method to produce the training data automatically. In addition, the training data were updated in the process of minimizing the energy function of the model. To evaluate the accuracy of the model, we applied the proposed method to three benchmark SAR data sets. The proposed model obtains 84.65%, 87.07%, and 96.26% of the Kappa coefficient for Yellow River Estuary, Bern, and Ottawa sample data sets, respectively. These results demonstrated the effectiveness of the proposed approach compared to other methods. Another advantage of the proposed model is its high speed in comparison to the conventional methods.


NANO ◽  
2009 ◽  
Vol 04 (03) ◽  
pp. 171-176 ◽  
Author(s):  
DAVOOD FATHI ◽  
BEHJAT FOROUZANDEH

This paper introduces a new technique for analyzing the behavior of global interconnects in FPGAs, for nanoscale technologies. Using this new enhanced modeling method, new enhanced accurate expressions for calculating the propagation delay of global interconnects in nano-FPGAs have been derived. In order to verify the proposed model, we have performed the delay simulations in 45 nm, 65 nm, 90 nm, and 130 nm technology nodes, with our modeling method and the conventional Pi-model technique. Then, the results obtained from these two methods have been compared with HSPICE simulation results. The obtained results show a better match in the propagation delay computations for global interconnects between our proposed model and HSPICE simulations, with respect to the conventional techniques such as Pi-model. According to the obtained results, the difference between our model and HSPICE simulations in the mentioned technology nodes is (0.29–22.92)%, whereas this difference is (11.13–38.29)% for another model.


2013 ◽  
Vol 441 ◽  
pp. 212-216
Author(s):  
Zhen Guang Liang ◽  
Yu Ze Jiang ◽  
Di Wen Jiang ◽  
Zong Jie Liu

This paper studied influence of three dimension complex ground on electric field under overhead lines. Surface charge method is discussed and planar triangle surface charge elements are used to represent complex ground. Electric field of overhead lines is analyzed by charge simulation method. Finite straight line charges are used to represent conductors. Then electric field of 220kV double circuit overhead lines over a three dimension small hill is calculated and distribution of electric field 1.5m above the ground is analyzed.


2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Chuen-Lin Tien ◽  
Rong-Ji Lin ◽  
Shang-Min Yeh

Light leakage from liquid crystal displays in the dark state is relatively larger and leads to a degraded contrast ratio and color shift. This work describes a novel colorimetric model based on the Muller matrix that includes depolarization of light propagating through liquid crystal molecules, polarizers, and color filters. In this proposed model, the chromaticity can be estimated in the bump and no-bump regions of an LCD. We indicate that the difference between simulation and measurement of chromaticity is about 0.01. Light leakage in the bump region is three times that in no-bump region in the dark state.


Author(s):  
T. A. Akhmetov ◽  
V. K. Merinov ◽  
N. V. Kargapolova

The possibility of using the deposited suspended particles of electric arc furnaces as heat-resistant modifying additives for friction composites is considered. It is shown that the precipitated particles obtained during the smelting of steel of different grades have identical morphology and are a homogeneous mechanical mixture consisting mainly of spherical particles of no more than 1 µm in size.It is established that the composites on the basis of the fluoropolymer, modified by precipitated particles obtained in the smelting of steel of various sizes have different tribological properties. This is due to the difference in the chemical composition of the deposited particles.It was found that the use of deposited particles in composite materials allows to vary the value of the dynamic friction coefficient in a wider range, in particular to obtain higher and stable values, while the wear resistance of modified friction composites is more than 500 times higher than the same index of the matrix polymer – polytetrafluoroethylene.


2021 ◽  
Author(s):  
Yingruo Fan ◽  
Jacqueline CK Lam ◽  
Victor On Kwok Li

<div> <div> <div> <p>Facial emotions are expressed through a combination of facial muscle movements, namely, the Facial Action Units (FAUs). FAU intensity estimation aims to estimate the intensity of a set of structurally dependent FAUs. Contrary to the existing works that focus on improving FAU intensity estimation, this study investigates how knowledge distillation (KD) incorporated into a training model can improve FAU intensity estimation efficiency while achieving the same level of performance. Given the intrinsic structural characteristics of FAU, it is desirable to distill deep structural relationships, namely, DSR-FAU, using heatmap regression. Our methodology is as follows: First, a feature map-level distillation loss was applied to ensure that the student network and the teacher network share similar feature distributions. Second, the region-wise and channel-wise relationship distillation loss functions were introduced to penalize the difference in structural relationships. Specifically, the region-wise relationship can be represented by the structural correlations across the facial features, whereas the channel-wise relationship is represented by the implicit FAU co-occurrence dependencies. Third, we compared the model performance of DSR-FAU with the state-of-the-art models, based on two benchmarking datasets. Our proposed model achieves comparable performance with other baseline models, though requiring a lower number of model parameters and lower computation complexities. </p> </div> </div> </div>


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Neveen Sayed-Ahmed ◽  
M. M. Amein ◽  
Taghreed M. Jawa ◽  
Tahani A. Aloafi ◽  
F. S. Bayones ◽  
...  

A statistical method is applied to predict the behaviour of a quantum model consisting of a qubit interacting with a single-mode cavity field. The qubit is prepared in excited state while the field starts from the binomial distribution state. The wave function of the proposed model is obtained. A von Neumann entropy is used to investigate the behaviour of the entanglement between the field and the qubits. Moreover, the atomic Q and Wigner functions are used to identify the behaviour of the distribution in a phase space. The simulation method is used to estimate the parameters of the proposed model to reach the best results. A numerical study is performed to estimate the specific dependency of the binomial distribution state. The results of entanglement were compared with the atomic Q and Wigner functions. The results showed that there are many maximum values of entanglement periodically. The results also confirmed a correlation between von Neumann entropy, the atomic Q , and Wigner functions.


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