scholarly journals Research on the Fast and Accurate Estimation Method of Sag Voltage

2021 ◽  
Vol 31 (5) ◽  
pp. 39-46
Keyword(s):  
Working Conditions ◽  
Taylor Series ◽  
Estimation Method ◽  
Taylor Series Expansion ◽  
Electrical Equipment ◽  
Accurate Estimation ◽  
Detection Time ◽  
Distribution Grid ◽  
Time Of Failure

Sag voltage affects the quality of the grid voltage and the working conditions of the electrical equipment. In order to prevent effectively this problem, the authors investigated the estimation method of fast and accurate voltage and phase angle in the presence of sag voltage. The method proposed Least Error Squares (LES) were constructed on the basis of the least squares algorithm and Taylor series expansion. Compared with conventional Clark and Park methods, the LES approach has the following major advantages: faster detection time, reduced deviation of estimated voltage values at the time of failure; faster detection time, reduced deviation of estimated voltage values at the time of failure; being not affected by other fundamental components 50Hz, the DC components in the grid. The effectiveness of the method is verified by simulation model of a distribution grid in Vinh Phuc province by Matlab / SIMULINK software.

A New Friction Estimation Approach for Precision Positioner

2007 ◽  
Author(s):  
Wen Wang ◽  
Xinxin Li ◽  
Zichen Chen
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Taylor Series ◽  
Estimation Method ◽  
Estimation Accuracy ◽  
Accurate Estimation ◽  
Low Velocity ◽  
Friction Estimation ◽  
Simulation Results ◽  
Long Stroke

Precision positioner has been significantly developed as the rapid growth of MEMS and IC industries. As for short-stroke position, the loss of friction can be avoided by using flexible hinges. Long-stroke postioner, however, in which moved-to-be mass always stands on the guide-way part, a main source of friction, makes friction unavoidable. Friction estimation is based on certain filters, such as Extended Kalman filter (EKF). However, estimation accuracy of Kalman filter, especially at low-velocity movement, is not very well. To solve this problem, the paper proposes an estimation method based on DD2 to make an accurate estimation. And the result shows this method is promising in real-time friction estimation. After background introduction, in section 2, the relation of EKF and Taylor series and EKF implementation are reviewed and its limitations are noted as well. A briefly introduction to DD2 is given in Section 3 and friction estimation case comparing the simulation results of DD2 estimation with that of EKF described in Section 4, respectively. At last, conclusions are summarized.

scholarly journals Mobile GPS Application Design Based on System-Level Power and Battery Status Estimation

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5333
Author(s):  
Jaemin Kim ◽  
Naehyuck Chang ◽  
Donghwa Shin
Keyword(s):  
Quality Of Service ◽  
Service Quality ◽  
Operating Time ◽  
Estimation Method ◽  
Mobile Systems ◽  
System Level ◽  
Accurate Estimation ◽  
Display Device ◽  
Application Design

Mobile systems such as smartphones require accurate estimation of the battery-related features including the remaining energy and operating time, especially as the the power consumption of user applications is growing continuously these days. We present an energy-aware smartphone application design framework that considers the battery’s state of charge (SOC), energy depletion rate, as well as the service quality of the target application. We use a verified-accurate battery energy estimation method in an Android-OS-based mobile computing system. The battery model considers the rate-capacity effect. We apply regression-based models for the power estimation of the major subsystems in the smartphone, and then aggregate the result to yield the whole system’s power. We first determine the quality of service for the location device (GPS), the display device (LCD), and the overall system (application). Then, we control the error rate of the GPS and the brightness of the display to acquire the maximum service quality of the system for a given car trip. We show the advantage of the proposed method with a case study of a trip. In this case, the smartphone guides a user’s car trip using its GPS navigation capabilities; to do this, we propose an adaptive algorithm that exploits our improved SOC estimation and considers the car’s variable velocity. This proposed adaptive power and service quality control of the GPS application improves the quality of service in this example case and ensures there is enough remaining battery for the trip to be completed. In contrast, conventional approaches to this task provide a lower quality of service and run out of battery before the trip finishes. In conclusion, if a trip plan is provided, an application using our method delivers the maximum quality of service, such as system endurance time, location error, and display brightness.

Investigation of Accuracy of a Calibrated Estimator of a Ratio by Modelling

2005 ◽  
Vol 10 (4) ◽  
pp. 333-342
Author(s):  
V. Chadyšas ◽  
D. Krapavickaitė
Keyword(s):  
Mean Square Error ◽  
Taylor Series ◽  
Random Sampling ◽  
Finite Population ◽  
Taylor Series Expansion ◽  
Simple Random Sampling ◽  
Population Parameter ◽  
Mean Square ◽  
Parameter Ratio ◽  
Using Data

Estimator of finite population parameter – ratio of totals of two variables – is investigated by modelling in the case of simple random sampling. Traditional estimator of the ratio is compared with the calibrated estimator of the ratio introduced by Plikusas [1]. The Taylor series expansion of the estimators are used for the expressions of approximate biases and approximate variances [2]. Some estimator of bias is introduced in this paper. Using data of artificial population the accuracy of two estimators of the ratio is compared by modelling. Dependence of the estimates of mean square error of the estimators of the ratio on the correlation coefficient of variables which are used in the numerator and denominator, is also shown in the modelling.

scholarly journals Determination of Environmental Factors for the Implementation of the Exploitability Index in Industrial Aggregate Mining Using Multi-Criteria Analysis

2021 ◽  
Vol 10 (4) ◽  
pp. 196
Author(s):  
Julio Manuel de Luis-Ruiz ◽  
Benito Ramiro Salas-Menocal ◽  
Gema Fernández-Maroto ◽  
Rubén Pérez-Álvarez ◽  
Raúl Pereda-García
Keyword(s):  
Environmental Factors ◽  
Environmental Factor ◽  
Human Life ◽  
Accurate Estimation ◽  
Analytic Hierarchy ◽  
Main Components ◽  
Hierarchy Process ◽  
Made In

The quality of human life is linked to the exploitation of mining resources. The Exploitability Index (EI) assesses the actual possibilities to enable a mine according to several factors. The environment is one of the most constraining ones, but its analysis is made in a shallow way. This research is focused on its determination, according to a new preliminary methodology that sets the main components of the environmental impact related to the development of an exploitation of industrial minerals and its weighting according to the Analytic Hierarchy Process (AHP). It is applied to the case of the ophitic outcrops in Cantabria (Spain). Twelve components are proposed and weighted with the AHP and an algorithm that allows for assigning a normalized value for the environmental factor to each deposit. Geographic Information Systems (GISs) are applied, allowing us to map a large number of components of the environmental factors. This provides a much more accurate estimation of the environmental factor, with respect to reality, and improves the traditional methodology in a substantial way. It can be established as a methodology for mining spaces planning, but it is suitable for other contexts, and it raises developing the environmental analysis before selecting the outcrop to be exploited.

Working Conditions and Special Educators’ Reading Instruction for Students With Emotional and Behavioral Disorders

2021 ◽  
pp. 001440292199982
Author(s):  
Hannah Morris Mathews ◽  
Jennifer L. Lillis ◽  
Elizabeth Bettini ◽  
David J. Peyton ◽  
Daisy Pua ◽  
...  
Keyword(s):  
Reading Instruction ◽  
Behavioral Disorders ◽  
Working Conditions ◽  
Special Educators ◽  
Emotional And Behavioral Disorders ◽  
Collegial Support ◽  
Instruction Time ◽  
Role Conceptions ◽  
Students With Ebd

Working conditions may be an important lever to support special educators’ reading instruction for students with emotional and behavioral disorders (EBD). Thus, we explored how working conditions relate to the quality of special educators’ reading instruction in upper-elementary, self-contained classes for students with EBD. Using mixed methods to examine video observations of reading instruction and varied data sources on working conditions, we found that special educators who provided stronger instruction had a partner coleading their program, and consistent paraprofessionals, with time and support for training. Partners and paraprofessionals, together, protected special educators’ instruction time. Other conditions (i.e., material resources, role differentiation, role conceptions, planning time) emerged as potentially important, but evidence was less robust. Results indicate partners and paraprofessionals may be important forms of collegial support. These findings have important implications for improving the quality of instruction in self-contained settings for students with EBD.

scholarly journals Research on a novel data-driven aging estimation method for battery systems in real-world electric vehicles

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110277
Author(s):  
Yankai Hou ◽  
Zhaosheng Zhang ◽  
Peng Liu ◽  
Chunbao Song ◽  
Zhenpo Wang
Keyword(s):  
Electric Vehicles ◽  
Real World ◽  
Regression Models ◽  
Estimation Method ◽  
Recursive Least Squares ◽  
Data Driven ◽  
Accurate Estimation ◽  
Support Vector ◽  
Battery Degradation ◽  
Operational Data

Accurate estimation of the degree of battery aging is essential to ensure safe operation of electric vehicles. In this paper, using real-world vehicles and their operational data, a battery aging estimation method is proposed based on a dual-polarization equivalent circuit (DPEC) model and multiple data-driven models. The DPEC model and the forgetting factor recursive least-squares method are used to determine the battery system’s ohmic internal resistance, with outliers being filtered using boxplots. Furthermore, eight common data-driven models are used to describe the relationship between battery degradation and the factors influencing this degradation, and these models are analyzed and compared in terms of both estimation accuracy and computational requirements. The results show that the gradient descent tree regression, XGBoost regression, and light GBM regression models are more accurate than the other methods, with root mean square errors of less than 6.9 mΩ. The AdaBoost and random forest regression models are regarded as alternative groups because of their relative instability. The linear regression, support vector machine regression, and k-nearest neighbor regression models are not recommended because of poor accuracy or excessively high computational requirements. This work can serve as a reference for subsequent battery degradation studies based on real-time operational data.

School Catchment Zone Mergers and Housing Wealth Redistribution

2021 ◽  
pp. 0739456X2110067
Author(s):  
Siu Kei Wong ◽  
Kuang Kuang Deng
Keyword(s):  
School Quality ◽  
Housing Prices ◽  
Estimation Method ◽  
Policy Implications ◽  
Housing Wealth ◽  
Housing Values ◽  
Wealth Redistribution ◽  
The Government ◽  
Empirical Design

This study investigates how perceived school quality affects housing values, using a new estimation method. Our empirical design takes advantage of the mergers of school catchment zones initiated by the government to develop quasi-experiments. We find that, in zones that gained sudden access to higher ranked schools, housing prices increased by 1.3 to 4.1 percent. Larger and more expensive houses appreciated more in response to the improvement in perceived quality of available schools. The findings generate important policy implications regarding housing wealth redistribution and housing expenditures among different households. The study also enriches the literature on the capitalization effect of school quality.

Comparison Experiment for Two Kinds of Hypoid Gear Drives

2010 ◽  
Vol 20-23 ◽  
pp. 1385-1390
Author(s):  
Hong Bin Yang ◽  
Xiao Hong Wang ◽  
Zong De Fang
Keyword(s):  
Working Conditions ◽  
Test Object ◽  
Hypoid Gear ◽  
Gear Drive ◽  
Comparison Experiment ◽  
Gear Drives

To develop a good quality of hypoid gear drive, the authors test the vibration and noise of two kinds of hypoid gear drives under different working conditions. The test object is a pair of hypoid gear drive used in the back axle of one minivan and a designed hypoid gear drive with high teeth based on the former. The results indicate that the hypoid gear drive with high teeth has lower vibration and noise.

Sign in / Sign up

Export Citation Format

Share Document