期刊文献+
共找到1,377篇文章
< 1 2 69 >
每页显示 20 50 100
From Differential Mode of Association to Tianxia Worldview:A Study on Chinese Entrepreneurial Spirit
1
作者 Chao Gang Qian Chen Wang Lei 《China Economist》 2024年第4期58-88,共31页
China has made significant strides in economic and social development since reform and opening up over the past four decades.This process has been influenced by the exceptional innovation and entrepreneurship of Chine... China has made significant strides in economic and social development since reform and opening up over the past four decades.This process has been influenced by the exceptional innovation and entrepreneurship of Chinese business leaders,as well as their profound sentiments of compassion for the world and their country.It is of great significance to foster and promote an entrepreneurial spirit with distinctive Chinese characteristics.Not only is such spirit essential to the high-quality development of enterprises and the economy,but it is also a critical impetus for achieving Chinese modernization.Nevertheless,there is still a paucity of adequate theoretical discourse on the cultural origins and entrepreneurial spirit of outstanding Chinese business leaders.This paper employs the classical grounded theory method to conduct a 10-year follow-up research on 11 representative entrepreneurs and their enterprises.The results indicate that these entrepreneurs exhibit an evolving worldview along the paths of“self-cultivation and moral conduct”,“assisting employees to achieve”,“multilateral symbiosis”,and“the oneness of existence”when interacting with themselves,employees,partners,the general public,and all things in nature.Such entrepreneurial spirit is embodied in this paper as the“Tianxia(all-under-heaven)worldview”.Through theoretical construction,this study defines the concept of“Tianxia worldview”and extensively examines the distinctions and connections between the broadminded“Tianxia worldview”and the kinship-centered“differential mode of association”in terms of internal structure,value orientation,and applicable groups.It is posited that the transition from the former to the latter is a continuous process of transcendence and evolution of the individual mindset.This study has theoretical significance in the context of advancing the research on the Chinese entrepreneurial spirit,transcending the constraints of the management approach based on the“differential mode of association”,and enhancing the research on social responsibility from the perspective of“benefit corporations”.It also has practical value in overcoming the trust dilemma and development impediment of family businesses,ensuring that enterprises consciously fulfill their social responsibilities in a broader social context,and achieving common prosperity and progress for both enterprises and society. 展开更多
关键词 Tianxia worldview differential mode of association Chinese entrepreneurial spirit corporate social responsibility grounded theory method
下载PDF
How Group Leaders Build Stable Community Buying Groups:A Perspective Based on the Differential Mode of Association
2
作者 SI Xiang 《Psychology Research》 2024年第1期30-35,共6页
Since 2016,community group buying has grown significantly in China,largely driven by its efficient logistics,supply chains,low prices,and convenience.This model has been further popularized during the COVID-19 pandemi... Since 2016,community group buying has grown significantly in China,largely driven by its efficient logistics,supply chains,low prices,and convenience.This model has been further popularized during the COVID-19 pandemic due to its effectiveness in meeting daily needs while minimizing human-to-human contact.A key component of this business model is the“group leaders”-influential individuals within a community responsible for managing group buying activities,which include order collection,supplier liaison,and goods distribution.Their primary task is to form and sustain a reliable community group buying consortium,a task that demands excellent organizational and interpersonal skills.This paper examines this phenomenon using the lens of the differential mode of association,a theoretical model explaining interpersonal relationships in traditional Chinese society.The research indicates that group leaders,through regular interaction with consumers,are able to alter their social network position,increase their influence,understand consumer needs,provide satisfying services,and enhance trust,thereby transforming consumers into loyal group buying participants.This transformation not only brings stability to group buying activities but also reinforces the community influence of group leaders,thus fostering the growth of community group buying. 展开更多
关键词 Community group buying China Group leaders The differential mode of association
下载PDF
A Simplified Sliding Mode Controlled Electronic Differential for an Electric Vehicle with Two Independent Wheel Drives 被引量:7
3
作者 Azeddine Draou 《Energy and Power Engineering》 2013年第6期416-421,共6页
This paper presents a simple sliding mode control strategy used for an electronic differential system for electric vehicle with two independent wheel drives. When a vehicle drives along a curved road lane, the speed o... This paper presents a simple sliding mode control strategy used for an electronic differential system for electric vehicle with two independent wheel drives. When a vehicle drives along a curved road lane, the speed of the inner wheel has to be different from that of the outer wheel in order to prevent the vehicle from vibrating and travelling an unsteady path. Because each wheel of this electrical vehicle has independent driving force, an electrical differential system is required to replace a gear differential system. However, it is difficult to analyse the nonlinear behaviour of the differential system in relation to the speed and steering angle, as well as vehicle structure. The proposed propulsion system consists of two permanent magnet synchronous machines that ensure the drive of the two back driving wheels. The proposed control structure called independent machines for speed control allows the achievement of an electronic differential which ensures the control of the vehicle behaviour on the road. It also allows to control, independently, every driving wheel to turn at different speeds in any curve. Analysis and simulation results of the proposed system are presented in this paper. 展开更多
关键词 Electric Vehicle SLIDING mode Control Electronic differential PERMANENT MAGNET SYNCHRONOUS Motor Multimachine Multiconverter System
下载PDF
Sliding Mode Control for Fractional Differential Systems with State-delay 被引量:5
4
作者 SI Jia-fang JIANG Wei 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第1期117-122,共6页
The problem of sliding mode control for fractional differential systems with statedelay is considered.A novel sliding surface is proposed and a controller is designed correspondingly,such that the state starting from ... The problem of sliding mode control for fractional differential systems with statedelay is considered.A novel sliding surface is proposed and a controller is designed correspondingly,such that the state starting from any initial value will move toward the switching surface and reach the sliding surface in finite time and the state variables on the sliding surface will converge to equilibrium point.And the stability of the proposed control design is discussed. 展开更多
关键词 sliding mode control fractional differential system TIME-DELAY
下载PDF
Five New MVL Current Mode Differential Absolute Value Circuits Based on Carbon Nano-tube Field Effect Transistors(CNTFETs) 被引量:2
5
作者 Mojtaba Jamalizadeh Fazel Sharifi +2 位作者 Mohammad Hossein Moaiyeri Keivan Navi Omid Hashemipour 《Nano-Micro Letters》 SCIE EI CAS 2010年第4期227-234,共8页
Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired ... Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired connection.Also,direction of the current can be used to exhibit the sign of digits.It is expected that the advantages of current mode approaches will become even more important with increased speed requirements and decreased supply voltage.In this paper,we present five new circuit designs for differential absolute value in current mode logic which have been simulated by CNTFET model.The considered base current for this model is 2 μA and supply voltage is 0.9 V.In all of our designs we used N-type CNTFET current mirrors which operate as truncated difference circuits.The operation of Differential Absolute Value circuit calculates the difference between two input currents and our circuit designs are operate in 8 logic levels. 展开更多
关键词 CNTFET Current mode Truncated difference differential absolute value
下载PDF
Buck Converter Current Measurement Using Differential Amplifier
6
作者 P.Rajeswari V.Manikandan 《Intelligent Automation & Soft Computing》 SCIE 2023年第2期1387-1402,共16页
The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affec... The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affected by several parameters which includes the type of technology used,components used for the selected technology,aging,usage,operating and environmental conditions.The effect of gain resistors and their manufacturing tolerances on differential amplifier-based buck converter current measurement is investigated in this work.The analysis mainly focused on the output voltage variation and its accuracy with respect to the change in gain resistance tolerances.The gain resistors with 5%,1%,0.5%and 0.1%manufacturing tolerances taken for the worst-case analysis and the calculated performance results are compared and verified with the simula-tion results.The Operational amplifiers(Op-Amp)for high frequency power con-verter applications must operate in a high frequency noise environment and the intended current measuring system must manage common mode noise distur-bances paired with the signal to be measured.Based on the Common Mode Rejec-tion Ratio(CMRR)the common mode voltages and noise signals will effectively getfiltered out.Lesser CMRR results in lower common mode signal rejection,resulting in poor precision and noise rejection.In differential amplifiers,the CMRR predominantly depends on gain resistors.So,the variations in Common Mode Rejection Ratio due to gain resistor tolerances also analyzed and compared with the output voltage variations.Besides the effects of resistor tolerances,this paper also examines the effect of Op-Amp offset voltage on output accuracy spe-cifically for low magnitude input currents.The obtained results from this analysis clearly shows that the gain resistors with 0.1%tolerance gives maximum accuracy with improved CMRR and accuracy at low magnitude input currents will get well improved by using Op-Amps with Low Offset voltage specifications. 展开更多
关键词 Buck converter common mode rejection ratio common mode gain current sensing differential amplifier differential mode gain shunt resistor
下载PDF
Research on Federated Learning Data Sharing Scheme Based on Differential Privacy
7
作者 Lihong Guo 《Computers, Materials & Continua》 SCIE EI 2023年第3期5069-5085,共17页
To realize data sharing,and to fully use the data value,breaking the data island between institutions to realize data collaboration has become a new sharing mode.This paper proposed a distributed data security sharing... To realize data sharing,and to fully use the data value,breaking the data island between institutions to realize data collaboration has become a new sharing mode.This paper proposed a distributed data security sharing scheme based on C/S communication mode,and constructed a federated learning architecture that uses differential privacy technology to protect training parameters.Clients do not need to share local data,and they only need to upload the trained model parameters to achieve data sharing.In the process of training,a distributed parameter update mechanism is introduced.The server is mainly responsible for issuing training commands and parameters,and aggregating the local model parameters uploaded by the clients.The client mainly uses the stochastic gradient descent algorithm for gradient trimming,updates,and transmits the trained model parameters back to the server after differential processing.To test the performance of the scheme,in the application scenario where many medical institutions jointly train the disease detection system,the model is tested from multiple perspectives by taking medical data as an example.From the testing results,we can know that for this specific test dataset,when the parameters are properly configured,the lowest prediction accuracy rate is 90.261%and the highest accuracy rate is up to 94.352.It shows that the performance of the model is good.The results also show that this scheme realizes data sharing while protecting data privacy,completes accurate prediction of diseases,and has a good effect. 展开更多
关键词 Federated learning C/S mode differential privacy gradient descent prediction accuracy
下载PDF
Differential Alterations of Lipid Status and Lipid Metabolism, Induction of Oxidative Stress by Sodium Arsenate in Female Rat's Liver and Kidney 被引量:2
8
作者 Kharroubi Wafa Dhibi Madiha +3 位作者 Chreif Imed Gérard Lizard Hammami Mohamed Sakly Rachid 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第11期829-833,共5页
Three groups of female rats (n=6 per group) were exposed to 1 and 10 mg/L of sodium arsenate for 90 days. The antioxidant and peroxidation parameters in kidney and liver tissues were evaluated, also the fatty acid c... Three groups of female rats (n=6 per group) were exposed to 1 and 10 mg/L of sodium arsenate for 90 days. The antioxidant and peroxidation parameters in kidney and liver tissues were evaluated, also the fatty acid composition were determined. In liver the synthesis pathway of n-3 polyunsaturated fatty acids (PUFA) seemed to be more affected than the n-6 PUFA, while in kidney the n-6 pathway was more affected. 展开更多
关键词 PUFA differential Alterations of Lipid status and Lipid Metabolism
下载PDF
K-Modes聚类数据收集和发布过程中的混洗差分隐私保护方法 被引量:1
9
作者 蒋伟进 陈艺琳 +3 位作者 韩裕清 吴玉庭 周为 王海娟 《通信学报》 EI CSCD 北大核心 2024年第1期201-213,共13页
针对目前聚类数据收集与发布安全性不足的问题,为保护聚类数据中的用户隐私并提高数据质量,基于混洗差分隐私模型,提出一种去可信第三方的K-Modes聚类数据收集和发布的隐私保护方法。首先,使用K-Modes聚类数据收集算法对用户数据进行采... 针对目前聚类数据收集与发布安全性不足的问题,为保护聚类数据中的用户隐私并提高数据质量,基于混洗差分隐私模型,提出一种去可信第三方的K-Modes聚类数据收集和发布的隐私保护方法。首先,使用K-Modes聚类数据收集算法对用户数据进行采样并加噪,再通过填补取值域随机排列发布算法打乱采样数据的初始顺序,使恶意攻击者不能根据用户与数据之间的关系识别出目标用户。然后,尽可能减小噪声的干扰,利用循环迭代的方式计算出新的质心完成聚类。最后,从理论层面上分析了以上3种方法的隐私性、可行性和复杂度,并利用3个真实数据集和近年来具有权威性的同类算法KM、DPLM、LDPKM等进行准确率、熵值的对比,验证所提方法的有效性。实验结果表明,所提方法的隐私保护和发布数据质量均优于当前同类算法。 展开更多
关键词 混洗差分隐私 K-modes聚类 隐私保护 数据收集 数据发布
下载PDF
Use of Double Differential-mode Current Injection Method Equivalent to High Level Illumination for Susceptibility Testing 被引量:3
10
作者 LU Xinfu WEI Guanghui PAN Xiaodong 《高电压技术》 EI CAS CSCD 北大核心 2013年第10期2431-2437,共7页
To achieve the electric field strength and the induced currents in equivalence in susceptibility tests with the high-level field radiation above 400 MHz,a double differential-mode(DM) current injection method based on... To achieve the electric field strength and the induced currents in equivalence in susceptibility tests with the high-level field radiation above 400 MHz,a double differential-mode(DM) current injection method based on directional couplers is proposed.Two cascaded symmetrical directional couplers compose a coupling device to inject the DM currents.When the coupling device is used,two devices are necessary to achieve the equivalence between radiation and injection,i.e.the equivalence between the injected voltages and the field strength,which is linear,regardless of the characteristics of the equipment under test(EUT).The results are verified by experiments using typical coaxial cables and nonlinear devices,where the equivalence between the nonlinear EUT responses induced by radiation and injection at both ends is achieved by using two coupling devices.At a frequency up to 1.75 GHz,the maximal experimental error is only 3.39%.The experimental results confirm the accuracy of the proposed method even both the EUTs work in the nonlinear region.The proposed method is applicable for radiated susceptibility(RS) testing of interconnected systems in the microwave frequency band. 展开更多
关键词 电流注入法 药敏试验 差模 定向耦合器 非线性器件 照明 实验误差 电场强度
下载PDF
Voltage-Mode Universal Biquad Filter Employing Single Voltage Differencing Differential Input Buffered Amplifier 被引量:2
11
作者 Kanhaiya Lal Pushkar Data Ram Bhaskar Dinesh Prasad 《Circuits and Systems》 2013年第1期44-48,共5页
A new multi function voltage-mode universal biquadratic filter using single Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA), two capacitors and one resistor is proposed. The proposed configuration... A new multi function voltage-mode universal biquadratic filter using single Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA), two capacitors and one resistor is proposed. The proposed configuration has four inputs and one output and can realize all the five standard filters from the same circuit configuration. The presented biquad filter offers low active and passive sensitivities. The validity of proposed universal biquadratic filter has been verified by SPICE simulation using 0.35 μm MIETEC technology. 展开更多
关键词 VOLTAGE Differencing differential INPUT Buffered AMPLIFIER ANALOG Filter VOLTAGE-mode
下载PDF
Research on the Equivalence Between Double Differential- mode Current Injection and Radiation Test Method 被引量:1
12
作者 PAN Xiaodong WEI Guanghui +2 位作者 FAN Lisi LU Xinfu YANG Zhe 《高电压技术》 EI CAS CSCD 北大核心 2013年第8期2031-2037,共7页
There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cab... There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system. 展开更多
关键词 测试方法 差模电流 辐射测试 电流注入 等价 BLT方程 相位关系 敏感性试验
下载PDF
Current Mode Universal Filter Using Single Current Controlled Differential Difference Current Conveyor Transconductance Amplifier
13
作者 Ajay Kumar Kushwaha Sajal K. Paul 《Circuits and Systems》 2015年第10期224-236,共13页
This research paper contains a new electronically tunable current-mode biquadratic universal filter using a new active building block;current controlled differential difference current conveyor transconductance amplif... This research paper contains a new electronically tunable current-mode biquadratic universal filter using a new active building block;current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA). The proposed filter provides the following important and desirable features: (i) One can use only one CCDDCCTA and two capacitors;(ii) One can get low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) current responses from the same configuration without any alteration;(iii) Passive components are grounded, which ease the integrated circuit implementation;(iv) Responses are electronically tunable;and (v) Sensitivity is low. Moreover, the non-ideality analysis shows that the parasitic passive components can be compensated for the proposed circuit. The functionality of the design is verified through SPICE simulations using 0.25 μm CMOS TSMC technology process parameters. Simulation result agrees well with the theoretical analysis. 展开更多
关键词 CURRENT mode Analog FILTER Universal FILTER CURRENT Controlled differential DIFFERENCE CURRENT CONVEYOR TRANSCONDUCTANCE Amplifier (CCDDCCTA) Monte-Carlo Analysis
下载PDF
基于k-modes聚类算法的混洗差分隐私方法
14
作者 祁富 陈丽敏 《牡丹江师范学院学报(自然科学版)》 2024年第2期6-13,共8页
首次提出一种基于k-modes聚类算法的混洗差分隐私保护方案(简称SDPk-modes).SDPk-modes根据每个数据之间的距离划分为不同的组,得到足够的细粒度优化效用,采用基于梯度随机扰动技术使计算最优概率耗时更短;在k-modes聚类过程中,通过将... 首次提出一种基于k-modes聚类算法的混洗差分隐私保护方案(简称SDPk-modes).SDPk-modes根据每个数据之间的距离划分为不同的组,得到足够的细粒度优化效用,采用基于梯度随机扰动技术使计算最优概率耗时更短;在k-modes聚类过程中,通过将数据中频繁出现的特征向量作为聚类中心点,基于属性熵的距离度量方法,加快算法收敛至聚类中心的速度,解决原始算法聚类速度慢、易陷入局部最优等问题,显著提高聚类的效果.实验验证表明,本文提出的方案优于当前同类方案. 展开更多
关键词 混洗差分隐私 k-modes 随机响应机制 隐私保护
下载PDF
Gradient Differentiation and Exploitation Mode of Tourist Resources in Hailuogou Scenic Area,China
15
作者 马晓路 许霞 《Journal of Landscape Research》 2011年第3期68-71,共4页
Natural environment of Hailuogou Scenic Area(Conch Gully)was introduced,and it was pointed out that tourist resources in the study area showed gradient differentiation along the vertical height.In view of such gradien... Natural environment of Hailuogou Scenic Area(Conch Gully)was introduced,and it was pointed out that tourist resources in the study area showed gradient differentiation along the vertical height.In view of such gradient differentiation,resource contents and characteristics of its cultural heritages zone,geothermal resources zone,forest vegetation zone,and glacial resources zone were respectively analyzed.Based on the gradient differentiation of tourist resources in Hailuogou Scenic Area,suggestions were given for its further tourism development,and it was stressed that brand effects of the attractions should be enhanced,infrastructure construction and maintenance of newly-explored scenic spots should be improved,and more efforts should be devoted to explore disastrous landform resources.This research is of practical significance for studying spatial differentiation and evolution mechanism of tourist resources in mountainous areas in western China,and also provides scientific support for the exploration of tourist resources in mountainous areas. 展开更多
关键词 TOURISM RESOURCES GRADIENT differentiATION EXPLOITATION mode Hailuogou
下载PDF
Differential mode-gain equalization via femtosecond laser micromachining-induced refractive index tailoring
16
作者 Cong Zhang Senyu Zhang +5 位作者 Yan Zeng Yue Wang Meng Xiang Di Lin Songnian Fu Yuwen Qin 《Light(Advanced Manufacturing)》 2024年第2期24-32,共9页
The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmis... The mode-division multiplexing technique combined with a few-mode erbium-doped fiber amplifier(FM-EDFA)demonstrates significant potential for solving the capacity limitation of standard single-mode fiber(SSMF)transmission systems.However,the differential mode gain(DMG)arising in the FM-EDFA fundamentally limits its transmission capacity and length.Herein,an innovative DMG equalization strategy using femtosecond laser micromachining to adjust the refractive index(RI)is presented.Variable mode-dependent attenuations can be achieved according to the DMG profile of the FM-EDFA,enabling DMG equalization.To validate the proposed strategy,DMG equalization of the commonly used FM-EDFA configuration was investigated.Simulation results revealed that by optimizing both the length and RI modulation depth of the femtosecond laser-tailoring area,the maximum DMG(DMGmax)among the 3 linear-polarized(LP)mode-group was mitigated from 10 dB to 1.52 dB,whereas the average DMG(DMGave)over the C-band was reduced from 8.95 dB to 0.78 dB.Finally,a 2-LP mode-group DMG equalizer was experimentally demonstrated,resulting in a reduction of the DMGmax from 2.09 dB to 0.46 dB,and a reduction of DMGave over the C band from 1.64 dB to 0.26 dB,with only a 1.8 dB insertion loss.Moreover,a maximum range of variable DMG equalization was achieved with 5.4 dB,satisfying the requirements of the most commonly used 2-LP mode-group amplification scenarios. 展开更多
关键词 mode-division multiplexing Few-mode Erbium-doped fiber amplifier differential mode gain Femtosecond laser micromachining
原文传递
Chiral asymmetry of anti-symmetric coordinates studied by the Raman differential bond polarizability of S-phenylethylamine
17
作者 沈红霞 吴国祯 王培杰 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第12期191-197,共7页
The Raman optical activity (ROA) study on S-phenylethylamine is presented by the intensity analyses via bond polarizability and differential bond polarizability. Ample information concerning the physical picture of ... The Raman optical activity (ROA) study on S-phenylethylamine is presented by the intensity analyses via bond polarizability and differential bond polarizability. Ample information concerning the physical picture of this chiral system is obtained, and its ROA mechanism is constructed. Especially, we propose that the asymmetric modes and/or the off-diagonal elements of the electronic polarizability tensor are the potential keys to the exploration of ROA. 展开更多
关键词 Raman optical activity intensity study asymmetric modes differential bond polariz-ability S-phenylethylamine
下载PDF
Adaptive Differentiators via Second Order Sliding Mode for a Fixed Wing Aircraft
18
作者 M.Zaouche A.Beloula +2 位作者 R.Louali S.Bouaziz M.Hamerlain 《Computer Modeling in Engineering & Sciences》 SCIE EI 2015年第3期159-184,共26页
Safety automation of complex mobile systems is a current topic issue in industry and research laboratories,especially in aeronautics.The dynamic models of these systems are nonlinear,Multi-Input Multi-Output(MIMO)and ... Safety automation of complex mobile systems is a current topic issue in industry and research laboratories,especially in aeronautics.The dynamic models of these systems are nonlinear,Multi-Input Multi-Output(MIMO)and tightly coupled.The nonlinearity resides in the dynamic equations and also in the aerodynamic coefficients’variability.This paper is devoted to developing the piloting law based on the combination of the robust differentiator with a dynamic adaptation of the gains and the robust controller via second order sliding mode,by using an aircraft in virtual simulated environments.To deal with the design of an autopilot controller,we propose an environment framework based on a Software In the Loop(SIL)methodology and we use Microsoft Flight Simulator(FS-2004)as the environment for plane simulation.The first order sliding mode control may be an appropriate solution to this piloting problem.However,its implementation generates a chattering phenomenon and a singularity problem.To overcome these problems,a new version of the adaptive differentiators for second order sliding modes is proposed and used for piloting.For the sliding mode algorithm,higher gains values may be used to improve accuracy;however this leads to an amplification of noise in the estimated signals.A good tradeoff between these two criteria(accuracy,robustness to noise ratio)is difficult to achieve.On the one hand,these values must increase the gains in order to derive a signal sweeping of some frequency ranges.On the other hand,low gains values have to be imposed to reduce noise amplification.So,our goal is to develop a differentiation algorithm in order to have a good compromise between error and robustness to noise ratio.To fit this requirement,a new version of differentiators with a higher order sliding modes and a dynamic adaptation of the gains,is proposed:the first order differentiator for the control of longitudinal speed and the second order differentiator for the control of the Euler angles. 展开更多
关键词 ADAPTIVE differentiators second order SLIDING modeS Dynamic adaptation of the GAINS Microsoft FLIGHT Simulator
下载PDF
Pressure-Driven Demand and Leakage Simulation for Pipe Networks Using Differential Evolution
19
作者 Naser Moosavian Mohammad Reza Jaefarzadeh 《World Journal of Engineering and Technology》 2013年第3期49-58,共10页
Traditional techniques for hydraulic analysis of water distribution networks, which are referred to as demand-driven simulation method (DDSM), are normally analyzed under the assumption that nodal demands are known an... Traditional techniques for hydraulic analysis of water distribution networks, which are referred to as demand-driven simulation method (DDSM), are normally analyzed under the assumption that nodal demands are known and satisfied. In many cases, such as pump outage or pipe burst, the demands at nodes affected by low pressures will decrease. Therefore, hydraulic analysis of pipe networks under deficient pressure conditions using conventional DDSM may cause large deviation from actual situations. In this paper, an optimization model is introduced for hydraulic analysis of water distribution networks using a meta-heuristic method called Differential Evolution (DE) algorithm. In this methodology, there is no need to solve linear systems of equations, there is a simple way to handle pressure-driven demand and leakage simulation, and it does not require an initial solution vector which is sometimes critical to the convergence. Also, the proposed model does not require any complicated mathematical expression and operation. 展开更多
关键词 HYDRAULIC Analysis differential Evolution Optimization mode
下载PDF
Water Gauge Image Denoising Model Based on Improved Adaptive Total Variation 被引量:1
20
作者 SHI Zhenting ZHOU Xianchun +2 位作者 ZHANG Ying LI Ting LU Siqi 《Instrumentation》 2023年第1期59-68,共10页
As an important part of water level warning in water conservancy projects,often due to the influence of environmental factors such as light and stains,the acquired water gauge images have sticky,broken and bright spot... As an important part of water level warning in water conservancy projects,often due to the influence of environmental factors such as light and stains,the acquired water gauge images have sticky,broken and bright spot conditions,which affect the identification of water gauges.To solve this problem,a water gauge image denoising model based on improved adaptive total variation is proposed.Firstly,the regular term exponent in the adaptive total variational equation is changed to an inverse cosine function;secondly,the differential curvature is used to distinguish the image noise points and increase the smoothing strength at the noise points;finally,according to the characteristics of the gradient mode and adaptive gradient threshold after Gaussian filtering,the New model can adaptively denoise in the smooth area and protect the edge area,so as to have the characteristics of both edge-preserving denoising.The experimental results show that the new model has a great improvement in image vision,higher iteration efficiency and an average increase of 1.6 dB in peak signal-to-noise ratio,and an average increase of 9%in structural similarity,which is more beneficial to practical applications. 展开更多
关键词 Water Gauge Image Adaptive Total Variation differential Curvature Gradient mode Adaptive Gradient Threshold
下载PDF
上一页 1 2 69 下一页 到第
使用帮助 返回顶部