A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for hig...A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction horizon.The input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive system.The RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test dataset.This proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot system.Training with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal disconnection.This Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive robots.Future work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode shift.The low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.展开更多
Effect of viscosity on flow patterns of pumping-up of liquid generated by a cone rotating at the liquid surface has been experimentally studied with various concentrations of glycerol aqueous solution. We have previou...Effect of viscosity on flow patterns of pumping-up of liquid generated by a cone rotating at the liquid surface has been experimentally studied with various concentrations of glycerol aqueous solution. We have previously found that the higher viscous non-Newtonian fluid was lifted-up along the conical surface with a radial filament-wise pattern, which is quite different from the monotonic thin film-wise pattern observed for the lower viscous fluid such as water. In order to elucidate the pumping-up mechanism, a transition diagram indicating the critical rotation rate is obtained as a function of viscosity?of Newtonian fluid in this study, varying from the lower value of water (μ?=?0.890 mPa·s) to the higher one of glycerin (μ?= 910?mPa·s). It is found that there are three categories depending on the viscosity classified as?1) film-wise pumping-up region for the viscosity?μ?≤?134?mPa·s,?2) filament-wise pumping-up one for the viscosity?μ?≥?520?mPa·s, and?3) no pumping-up phenomenon occurs?for 134??μ??mPa·s.展开更多
A new class of support structures, called Periodic Structures, is introduced in this paper as a viable means for isolating the vibration transmitted from the sea waves to offshore platform structures through its legs....A new class of support structures, called Periodic Structures, is introduced in this paper as a viable means for isolating the vibration transmitted from the sea waves to offshore platform structures through its legs. A passive approach to reduce transmitted vibration generated by waves is presented. The approach utilizes the property of periodic structural components that create stop and pass bands. The stop band regions can be tailored to correspond to regions of the frequency spectra that contain harmonics of the wave frequency, attenuating the response in those regions. A periodic structural component is comprised of a repeating array of cells, which are themselves an assembly of elements. The elements may have differing material properties as well as geometric variations. For the purpose of this research, only geometric and material variations are considered and each cell is assumed to be identical. A periodic leg is designed in order to reduce transmitted vibration of sea waves. The effectiveness of the periodicity on the vibration levels of platform will be demonstrated theoretically. The theory governing the operation of this class of periodic structures is introduced using the transfer matrix method. The unique filtering characteristics of periodic structures are demonstrated as functions of their design parameters for structures with geometrical and material discontinuities, and determine the propagation factor by using the spectral finite element analysis and the effectiveness of design on the leg structure by changing the ratio of step length and area interface between the materials is demonstrated in order to find the propagation factor and frequency response.展开更多
A dynamic hesitant fuzzy linguistic group decisionmaking(DHFLGDM) problem is studied from the perspective of information reliability based on the theory of hesitant fuzzy linguistic term sets(HFLTSs). First, an approa...A dynamic hesitant fuzzy linguistic group decisionmaking(DHFLGDM) problem is studied from the perspective of information reliability based on the theory of hesitant fuzzy linguistic term sets(HFLTSs). First, an approach is applied to transform the dynamic HFLTSs(DHFLTSs) into a set of proportional linguistic terms to eliminate the time dimension. Second, expert reliability is measured by considering both group similarity and degree of certainty, and an optimization method is employed to quantify the linguistic terms by maximizing the group similarity. Third, through computing the attribute stability as well as its reliability, a combination rule which considers both reliability and weight is proposed to aggregate the information, and then the aggregated grade values and degree of stability are used to make a selection. Finally,the application and feasibility of the proposed method are verified through a case study and method comparison.展开更多
The modified normal form approach presented by ZHANG Wei-yi, K Huseyin and CHEN Yu-shu is further extended and a different procedure is introduced which lends itself readily to symbolic calculations, like MAPLE. This ...The modified normal form approach presented by ZHANG Wei-yi, K Huseyin and CHEN Yu-shu is further extended and a different procedure is introduced which lends itself readily to symbolic calculations, like MAPLE. This provides a number of significant advantages over the previous approach, and facilitates the associated calculations. To illustrate the new approach, three examples are presented.展开更多
To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fab...To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fabricated.The material characteristics of ND,Ti_(3)C_(2)MXene,and ND/Ti_(3)C_(2)MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)spectroscopy.The experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti_(3)C_(2) MXene nanosheet prevented the self-stacking of Ti_(3)C_(2)MXene and enhanced the sensitivity of Ti_(3)C_(2) MXene-based QCM humidity sensor.Moreover,the high mechanical modulus of Ti_(3)C_(2) MXene material helped ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor to achieve a high quality factor(>20,000).ND/Ti_(3)C_(2)MXene compositecoated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/%RH,a humidity hysteresis of 1.1%RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3%RH to 97.3%RH.The response mechanism of ND/Ti_(3)C_(2) MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-exponential kinetic adsorption model.Finally,the potential application of ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.展开更多
In this paper,we present a twisting control scheme with proportional-integral-derivative(PID)sliding surface for a two-axis electrostatic torsional micromirror,and the utilization of the proposed scheme in a laser sca...In this paper,we present a twisting control scheme with proportional-integral-derivative(PID)sliding surface for a two-axis electrostatic torsional micromirror,and the utilization of the proposed scheme in a laser scanning system.The experimental results of set-point regulation verify that the proposed scheme provides enhanced transient response and positioning performance as compared to traditional sliding mode control.To evaluate the tracking performance of the closed-loop system,triangular waves with different frequencies are used as desired traces.With the proposed scheme the experimental results verified that the closed-loop controlled micromirror follows the given triangular trajectories precisely.A micromirror-based laser scanning system is developed to obtain images.When compared with open-loop control,the experimental results demonstrated that the proposed scheme is able to reduce the distortion of the raster scan,and improve the imaging performance in the presence of cross-coupling effect.展开更多
Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for au...Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.展开更多
The processes of globalization, the consequences of which are evident in all comers and at all levels of the contemporary world are linked to an increasing homogenization. Disciplines of architecture and urban design ...The processes of globalization, the consequences of which are evident in all comers and at all levels of the contemporary world are linked to an increasing homogenization. Disciplines of architecture and urban design contribute to that process, which is affecting the very definitions of place and identity. A desire to maintain and （re）create local identity within the context of that increasingly global world is connected to reviving of the past or to various interpretations of history, and preservation of the built environment of the place. This paper identifies peculiar processes of creation and maintenance of identity of place in the precincts of Tokyo Yanaka, Nezu and Sendagi, known as Yanesen. The authors argue that in Yanesen innovation appears as the byproduct of complex and creative responses to the threats of globalization, within a perpetual interplay of persistence and change. The paper opens a number of questions of where and how innovation in built environment can contribute to persistence of place identity.展开更多
Materials exhibiting auxetic properties have a negative Poisson’s ratio, which intrigued researchers to understand the behavior of auxetic structure. Several researchers focused on the different auxetic cell designs,...Materials exhibiting auxetic properties have a negative Poisson’s ratio, which intrigued researchers to understand the behavior of auxetic structure. Several researchers focused on the different auxetic cell designs, while others focused on the auxetic applications. With the advance of additive manufacturing methods, computer-aided design and finite element analysis in recent decades, auxetics have been explored. One of the interesting applications is in the field of biomedical devices or implants, especially for certain natural biomedical organs such as tissues, certain ligaments that have auxetic properties. This paper is an overview of auxetic design approaches and biomedical applications.展开更多
High-speed stirred mills are utilized to grind particles below 10mm. Grinding sulphide minerals to as low as 10mm achieve adequate mineral liberation for successful downstream mineral processing operations, such as fl...High-speed stirred mills are utilized to grind particles below 10mm. Grinding sulphide minerals to as low as 10mm achieve adequate mineral liberation for successful downstream mineral processing operations, such as flotation and leaching. Particle breakage mechanism such as fracture or abrasion, determines the morphological surface features of the product particles. It is anticipated that particles, which break along grain boundaries (intergranular) produce rough surfaces, whereas particles that break across the grain boundaries (transgranular) possess smoother surfaces. In this study, particles are ground in a stirred mill and their morphological features were analyzed using automated and manual detection methods. Literature and conventional belief are that high-speed stirred mills break particles by attrition. This paper showed that fracture is also an important breakage mechanism along with attrition. Breakage mechanism is a factor of input stress intensity, in the form of the mill agitator speed, and type of mineral. It is observed that at higher agitator speed galena fractures along the grain boundaries, whereas quartz, abrade across the grain boundaries.展开更多
At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is develope...At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is developed adapting on its application. In this study, a new ultrasonic motor structure that combines a piezoelectric element and a metallic plate is elaborated. The driving principle of this motor is that the metal plate is bent to an inchworm shape and rotates the rotor when the piezoelectric element is stretched. The objective of this study is to verify the functioning of the new motor experimentally.展开更多
A formal policy development framework, based on a system of systems （SOS） approach, is synthesized to systematically address, in an integrative and adaptive fashion, major global challenges, such as the current food...A formal policy development framework, based on a system of systems （SOS） approach, is synthesized to systematically address, in an integrative and adaptive fashion, major global challenges, such as the current food and fjnancial crises, and their interactions with other key natural, societal, and technological systems. A SoS approach seeks to respect the different value systems of multiple participants, to harness complexity through effective integration, and to engage the world of uncertainty and unpredictability with an adaptive response. Faced with the present global challenges, what is needed are strategic and operational methods which lead to ethical policies, enhance integrative and adaptive management practices, and are able to direct conflict resolution in a positive direction. Policy makers need tools to model and analyze complex systems which they are trying to responsibly govern, taking into account values and risks to design and evaluate different policies. A preliminary investigation into the global food system is undertaken to understand the SoS and to provide insights on how to carry out policy development using the proposed framework.展开更多
Purpose–The purpose of this paper is to apply a hybrid neuro-fuzzy paradigm called self-organizing neuro-fuzzy multilayered classifier(SONeFMUC)to classify the operating faults of a hydraulic system.The main motivati...Purpose–The purpose of this paper is to apply a hybrid neuro-fuzzy paradigm called self-organizing neuro-fuzzy multilayered classifier(SONeFMUC)to classify the operating faults of a hydraulic system.The main motivation behind the use of SONeFMUC is to attest the capabilities of neuro-fuzzy classifier for handling the difficulties associated with fault diagnosis of hydraulic circuits.Design/methodology/approach–In the proposed methodology,first,the neuro-fuzzy nodes at each layer of the SONeFMUC are trained separately using two well-known bio-inspired algorithms,i.e.a semi deterministic method with random walks called co-variance matrix adaptation evolutionary strategy(CMA-ES)and a swarm-based explorer with adaptive fuzzified parameters(SBEAFP).Thereafter,a revised version of the group method data handling(GMDH)policy that uses the Darwinian concepts such as truncation selection and elitism is engaged to connect the nodes of different layers in an effective manner.Findings–Based on comparative numerical experiments,the authors conclude that integration of neuro-fuzzy method and bio-inspired supervisor results in a really powerful classification tool beneficial for uncertain environments.It is proved that the method outperforms some well-known classifiers such as support vector machine(SVM)and particle swarm optimization-based SVM(PSOSVM).Besides,it is indicated that an efficient bio-inspired method can effectively adjust the constructive parameters of the multi-layered neuro-fuzzy classifier.For the case,it is observed that designing a fuzzy controller for PSO predisposes it to effectively balance the exploration/exploitation capabilities,and consequently optimize the structure of SONeFMUC.Originality/value–The originality of the paper can be considered from both numerical and practical points of view.The signals obtained through the data acquisition possess six different features in order for the hydraulic system to undergo four types of faults,i.e.cylinder fault,pump fault,valve leakage fault and rupture of the piping system.Besides,to elaborate on the authenticity and efficacy of the proposed method,its performance is compared with well-known rival techniques.展开更多
Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric fo...Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.展开更多
In this work,we introduce a novel Micro Circular Log-Periodic Antenna(MCLPA)optimized with an advanced Evolutionary Neural Network(ENN)algorithm,specifically designed to enhance terahertz(THz)radiation detection.By le...In this work,we introduce a novel Micro Circular Log-Periodic Antenna(MCLPA)optimized with an advanced Evolutionary Neural Network(ENN)algorithm,specifically designed to enhance terahertz(THz)radiation detection.By leveraging the adaptive capabilities of the ENN framework,the antenna design efficiency is significantly improved,enabling rapid prototyping and yielding highly optimized structures tailored for practical THz applications.Extensive characterization confirms that the proposed MCLPA achieves outstanding performance,including an ultra-broad operational bandwidth of 372 GHz(0.135-0.507 THz),a peak gain of 5.51 dBi,an optimal S-parameter(S11)of−13.68 dB,and a maximum radiation efficiency of 82.39%.In addition,the MCLPA exhibits superior sensitivity,low noise susceptibility,and fast response,which are key attributes for reliable and precise THz detection.When configured in array form,the design further enhances gain and directional responsiveness,demonstrating the scalability and deployment potential of the MCLPA.This ENN-driven MCLPA represents a significant breakthrough in THz antenna engineering,introducing a transformative design paradigm that synergistically integrates algorithmic intelligence with structural innovation.By substantially reducing design time and cost while achieving exceptional performance,the proposed ENN framework sets a new benchmark for the development of next-generation THz detection and communication systems,offering broad implications for future high-frequency technologies.展开更多
This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS opera...This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS operating in air to provide a simple architecture for FC generators.A biased voltage signal drives the electrical resonator at resonance which is set to match an integer submultiple of twice the mechanical resonator’s resonance.Experimental results demonstrate that the NEMS displacement exhibit more than 150 equidistant peaks in the case of a 2:1 modal interaction and more than 60 equidistant peaks in the case of a 1:1 modal interaction.In both cases,the Free Spectral Range(FSR)was equal to the mechanical resonance frequency.Comparison between the FCs generated by the 2:1 and 1:1 modal interactions demonstrate the superiority of the former in terms of bandwidth and stability.The superior phase coherence of the FC generated via the 2:1 modal interaction was demonstrated via time-domain analysis.Our technique has the flexibility to generate multiple frequency combs and to fine-tune their FSR depending on the number of mechanical modes accessible to and the order of the activated modal interaction.It can be integrated into portable devices and is well aligned with modern miniaturization technology.展开更多
Formal systems engineering approaches to modeling misperceptions and attitudes are employed within the framework of the graph model for conflict resolution to systematically study the War of 1812 between the United St...Formal systems engineering approaches to modeling misperceptions and attitudes are employed within the framework of the graph model for conflict resolution to systematically study the War of 1812 between the United States of America and Great Britain in order to provide enhanced insights into the causes of the war. More specifically, relational definitions for preferences, movements and stability concepts are defined for describing the attitudes and associated behavior of decision makers involved in a conflict. To capture misperceptions of decision makers in the War of 1812, attitudes are studied within the structure of a hypergame. Combining attitudes and misperceptions within the paradigm of the graph model furnishes the flexible analytical tool which demonstrates that misunderstanding of attitudes by Great Britain and the United States may have contributed to the outbreak of this nasty war.展开更多
Insightful theorems are established on interrelationships among coalition and noncooperative stability concepts defined within the paradigm of the Graph Model for Conflict Resolution. More specifically, the newly defi...Insightful theorems are established on interrelationships among coalition and noncooperative stability concepts defined within the paradigm of the Graph Model for Conflict Resolution. More specifically, the newly defined coalition stability def＇mitions that are considered are coalition Nash stability （CNash）, coalition general metarationality （CGMR）, coalition symmetric metarationality （CSMR） and coalition sequential stability （CSEQ）, along with their earlier-defined noncooperative versions. A range of interesting new theorems are derived to establish connections among these coalition stability concepts as well as between noncooperative and coalition stability definitions. Applications with respect to the games of Prisoner＇s Dilemma and Chicken, as well as a groundwater contamination dispute, demonstrate how the various stability definitions can be applied in practice and confirm the validity of some of the theorems as well as point out, by example, certain types of relationships which cannot hold.展开更多
A comparison of two decision analysis tools for the analysis of strategic conflicts, the Analytic Network Process （ANP） and the graph model for conflict resolution, is carried out by applying them to the China-US TV...A comparison of two decision analysis tools for the analysis of strategic conflicts, the Analytic Network Process （ANP） and the graph model for conflict resolution, is carried out by applying them to the China-US TV dumping conflict. Firstly, the graph model is introduced along with practical procedures for modeling and analyzing conflicts using the decision support software, GMCR Ⅱ. Next, ANP is explained, emphasizing structural features and procedures for synthesizing priorities. Then a framework for employing ANP to analyze strategic conflicts is designed and used to compare ANP to the graph model. The case study of the China-US TV dumping conflict provides a basis for the graph model and ANP to be compared; different features of the approaches are highlighted. The study shows that because of different theoretical backgrounds, ANP and the graph model for conflict analysis both provide useful information which can be combined to furnish a better understanding of a strategic conflict.展开更多
基金supported by funding from the Canada Research Chairs Program and the Natural Sciences and Engineering Research Council of Canada.The authors wish to thank Ekso Bionics Holdings Inc.for providing the Ekso EVO passive shoulder exoskeleton.
文摘A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction horizon.The input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive system.The RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test dataset.This proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot system.Training with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal disconnection.This Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive robots.Future work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode shift.The low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.
文摘Effect of viscosity on flow patterns of pumping-up of liquid generated by a cone rotating at the liquid surface has been experimentally studied with various concentrations of glycerol aqueous solution. We have previously found that the higher viscous non-Newtonian fluid was lifted-up along the conical surface with a radial filament-wise pattern, which is quite different from the monotonic thin film-wise pattern observed for the lower viscous fluid such as water. In order to elucidate the pumping-up mechanism, a transition diagram indicating the critical rotation rate is obtained as a function of viscosity?of Newtonian fluid in this study, varying from the lower value of water (μ?=?0.890 mPa·s) to the higher one of glycerin (μ?= 910?mPa·s). It is found that there are three categories depending on the viscosity classified as?1) film-wise pumping-up region for the viscosity?μ?≤?134?mPa·s,?2) filament-wise pumping-up one for the viscosity?μ?≥?520?mPa·s, and?3) no pumping-up phenomenon occurs?for 134??μ??mPa·s.
文摘A new class of support structures, called Periodic Structures, is introduced in this paper as a viable means for isolating the vibration transmitted from the sea waves to offshore platform structures through its legs. A passive approach to reduce transmitted vibration generated by waves is presented. The approach utilizes the property of periodic structural components that create stop and pass bands. The stop band regions can be tailored to correspond to regions of the frequency spectra that contain harmonics of the wave frequency, attenuating the response in those regions. A periodic structural component is comprised of a repeating array of cells, which are themselves an assembly of elements. The elements may have differing material properties as well as geometric variations. For the purpose of this research, only geometric and material variations are considered and each cell is assumed to be identical. A periodic leg is designed in order to reduce transmitted vibration of sea waves. The effectiveness of the periodicity on the vibration levels of platform will be demonstrated theoretically. The theory governing the operation of this class of periodic structures is introduced using the transfer matrix method. The unique filtering characteristics of periodic structures are demonstrated as functions of their design parameters for structures with geometrical and material discontinuities, and determine the propagation factor by using the spectral finite element analysis and the effectiveness of design on the leg structure by changing the ratio of step length and area interface between the materials is demonstrated in order to find the propagation factor and frequency response.
基金supported by the National Natural Science Foundation of China(71171112 71502073+2 种基金 71601002)the Scientific Innovation Research of College Graduates in Jiangsu Province(KYZZ150094)the Anhui Provincial Natural Science Foundation(1708085MG168)
文摘A dynamic hesitant fuzzy linguistic group decisionmaking(DHFLGDM) problem is studied from the perspective of information reliability based on the theory of hesitant fuzzy linguistic term sets(HFLTSs). First, an approach is applied to transform the dynamic HFLTSs(DHFLTSs) into a set of proportional linguistic terms to eliminate the time dimension. Second, expert reliability is measured by considering both group similarity and degree of certainty, and an optimization method is employed to quantify the linguistic terms by maximizing the group similarity. Third, through computing the attribute stability as well as its reliability, a combination rule which considers both reliability and weight is proposed to aggregate the information, and then the aggregated grade values and degree of stability are used to make a selection. Finally,the application and feasibility of the proposed method are verified through a case study and method comparison.
文摘The modified normal form approach presented by ZHANG Wei-yi, K Huseyin and CHEN Yu-shu is further extended and a different procedure is introduced which lends itself readily to symbolic calculations, like MAPLE. This provides a number of significant advantages over the previous approach, and facilitates the associated calculations. To illustrate the new approach, three examples are presented.
基金financially supported by the Project funded by the National Natural Science Foundation of China(No.61401047)the China Postdoctoral Science Foundation(No.2018M633349)+1 种基金the Oversea Students Funding Project of the Department of Human Resources and Social Security of Sichuanthe Scientific Research Foundation of CUIT(No.KYQN202210)。
文摘To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fabricated.The material characteristics of ND,Ti_(3)C_(2)MXene,and ND/Ti_(3)C_(2)MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)spectroscopy.The experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti_(3)C_(2) MXene nanosheet prevented the self-stacking of Ti_(3)C_(2)MXene and enhanced the sensitivity of Ti_(3)C_(2) MXene-based QCM humidity sensor.Moreover,the high mechanical modulus of Ti_(3)C_(2) MXene material helped ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor to achieve a high quality factor(>20,000).ND/Ti_(3)C_(2)MXene compositecoated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/%RH,a humidity hysteresis of 1.1%RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3%RH to 97.3%RH.The response mechanism of ND/Ti_(3)C_(2) MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-exponential kinetic adsorption model.Finally,the potential application of ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.
基金supported by the National Natural Science Foundation of China(61374036,61703142,U1504615)the Natural Science and Engineering Research Council of Canadathe Scientific Research Key Foundation of Higher Education Institutions of Henan Province(16A413001)
文摘In this paper,we present a twisting control scheme with proportional-integral-derivative(PID)sliding surface for a two-axis electrostatic torsional micromirror,and the utilization of the proposed scheme in a laser scanning system.The experimental results of set-point regulation verify that the proposed scheme provides enhanced transient response and positioning performance as compared to traditional sliding mode control.To evaluate the tracking performance of the closed-loop system,triangular waves with different frequencies are used as desired traces.With the proposed scheme the experimental results verified that the closed-loop controlled micromirror follows the given triangular trajectories precisely.A micromirror-based laser scanning system is developed to obtain images.When compared with open-loop control,the experimental results demonstrated that the proposed scheme is able to reduce the distortion of the raster scan,and improve the imaging performance in the presence of cross-coupling effect.
文摘Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.
文摘The processes of globalization, the consequences of which are evident in all comers and at all levels of the contemporary world are linked to an increasing homogenization. Disciplines of architecture and urban design contribute to that process, which is affecting the very definitions of place and identity. A desire to maintain and （re）create local identity within the context of that increasingly global world is connected to reviving of the past or to various interpretations of history, and preservation of the built environment of the place. This paper identifies peculiar processes of creation and maintenance of identity of place in the precincts of Tokyo Yanaka, Nezu and Sendagi, known as Yanesen. The authors argue that in Yanesen innovation appears as the byproduct of complex and creative responses to the threats of globalization, within a perpetual interplay of persistence and change. The paper opens a number of questions of where and how innovation in built environment can contribute to persistence of place identity.
文摘Materials exhibiting auxetic properties have a negative Poisson’s ratio, which intrigued researchers to understand the behavior of auxetic structure. Several researchers focused on the different auxetic cell designs, while others focused on the auxetic applications. With the advance of additive manufacturing methods, computer-aided design and finite element analysis in recent decades, auxetics have been explored. One of the interesting applications is in the field of biomedical devices or implants, especially for certain natural biomedical organs such as tissues, certain ligaments that have auxetic properties. This paper is an overview of auxetic design approaches and biomedical applications.
文摘High-speed stirred mills are utilized to grind particles below 10mm. Grinding sulphide minerals to as low as 10mm achieve adequate mineral liberation for successful downstream mineral processing operations, such as flotation and leaching. Particle breakage mechanism such as fracture or abrasion, determines the morphological surface features of the product particles. It is anticipated that particles, which break along grain boundaries (intergranular) produce rough surfaces, whereas particles that break across the grain boundaries (transgranular) possess smoother surfaces. In this study, particles are ground in a stirred mill and their morphological features were analyzed using automated and manual detection methods. Literature and conventional belief are that high-speed stirred mills break particles by attrition. This paper showed that fracture is also an important breakage mechanism along with attrition. Breakage mechanism is a factor of input stress intensity, in the form of the mill agitator speed, and type of mineral. It is observed that at higher agitator speed galena fractures along the grain boundaries, whereas quartz, abrade across the grain boundaries.
文摘At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is developed adapting on its application. In this study, a new ultrasonic motor structure that combines a piezoelectric element and a metallic plate is elaborated. The driving principle of this motor is that the metal plate is bent to an inchworm shape and rotates the rotor when the piezoelectric element is stretched. The objective of this study is to verify the functioning of the new motor experimentally.
基金support received from a strategic grant entitled"Systems Engineering Approaches for Brownfield Redevelopment"from the Natural Sciences and Engineering Research Council(NSERC) of Canada,from the Centre for International Governance Innovation (CIGI),and from the Social Sciences and Humanities Research Council(SSHRC) of Canada
文摘A formal policy development framework, based on a system of systems （SOS） approach, is synthesized to systematically address, in an integrative and adaptive fashion, major global challenges, such as the current food and fjnancial crises, and their interactions with other key natural, societal, and technological systems. A SoS approach seeks to respect the different value systems of multiple participants, to harness complexity through effective integration, and to engage the world of uncertainty and unpredictability with an adaptive response. Faced with the present global challenges, what is needed are strategic and operational methods which lead to ethical policies, enhance integrative and adaptive management practices, and are able to direct conflict resolution in a positive direction. Policy makers need tools to model and analyze complex systems which they are trying to responsibly govern, taking into account values and risks to design and evaluate different policies. A preliminary investigation into the global food system is undertaken to understand the SoS and to provide insights on how to carry out policy development using the proposed framework.
文摘Purpose–The purpose of this paper is to apply a hybrid neuro-fuzzy paradigm called self-organizing neuro-fuzzy multilayered classifier(SONeFMUC)to classify the operating faults of a hydraulic system.The main motivation behind the use of SONeFMUC is to attest the capabilities of neuro-fuzzy classifier for handling the difficulties associated with fault diagnosis of hydraulic circuits.Design/methodology/approach–In the proposed methodology,first,the neuro-fuzzy nodes at each layer of the SONeFMUC are trained separately using two well-known bio-inspired algorithms,i.e.a semi deterministic method with random walks called co-variance matrix adaptation evolutionary strategy(CMA-ES)and a swarm-based explorer with adaptive fuzzified parameters(SBEAFP).Thereafter,a revised version of the group method data handling(GMDH)policy that uses the Darwinian concepts such as truncation selection and elitism is engaged to connect the nodes of different layers in an effective manner.Findings–Based on comparative numerical experiments,the authors conclude that integration of neuro-fuzzy method and bio-inspired supervisor results in a really powerful classification tool beneficial for uncertain environments.It is proved that the method outperforms some well-known classifiers such as support vector machine(SVM)and particle swarm optimization-based SVM(PSOSVM).Besides,it is indicated that an efficient bio-inspired method can effectively adjust the constructive parameters of the multi-layered neuro-fuzzy classifier.For the case,it is observed that designing a fuzzy controller for PSO predisposes it to effectively balance the exploration/exploitation capabilities,and consequently optimize the structure of SONeFMUC.Originality/value–The originality of the paper can be considered from both numerical and practical points of view.The signals obtained through the data acquisition possess six different features in order for the hydraulic system to undergo four types of faults,i.e.cylinder fault,pump fault,valve leakage fault and rupture of the piping system.Besides,to elaborate on the authenticity and efficacy of the proposed method,its performance is compared with well-known rival techniques.
基金supported by the Samsung Electronics Co.,Ltd.(ISO230414-05954-01)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF2021R1A6A1A03039981)+2 种基金the Korea Institute for Advancement of Technology(KIAT)Grant,funded by the Korea Government(MOTIE)(P0023703,HRD Program for Industrial Innovation)The computations were performed at the Korea Institute of Science and Technology Information(KISTI)National Supercomputing Center(KSC-2024-CRE-0316)the UNIST Supercomputing Center。
文摘Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.
基金support from the Natural Sciences and Engineering Research Council of Canada(NSERC)and the Micro-Nano Technology(MNT)program facilitated by CMC Microsystems.
文摘In this work,we introduce a novel Micro Circular Log-Periodic Antenna(MCLPA)optimized with an advanced Evolutionary Neural Network(ENN)algorithm,specifically designed to enhance terahertz(THz)radiation detection.By leveraging the adaptive capabilities of the ENN framework,the antenna design efficiency is significantly improved,enabling rapid prototyping and yielding highly optimized structures tailored for practical THz applications.Extensive characterization confirms that the proposed MCLPA achieves outstanding performance,including an ultra-broad operational bandwidth of 372 GHz(0.135-0.507 THz),a peak gain of 5.51 dBi,an optimal S-parameter(S11)of−13.68 dB,and a maximum radiation efficiency of 82.39%.In addition,the MCLPA exhibits superior sensitivity,low noise susceptibility,and fast response,which are key attributes for reliable and precise THz detection.When configured in array form,the design further enhances gain and directional responsiveness,demonstrating the scalability and deployment potential of the MCLPA.This ENN-driven MCLPA represents a significant breakthrough in THz antenna engineering,introducing a transformative design paradigm that synergistically integrates algorithmic intelligence with structural innovation.By substantially reducing design time and cost while achieving exceptional performance,the proposed ENN framework sets a new benchmark for the development of next-generation THz detection and communication systems,offering broad implications for future high-frequency technologies.
基金K.M.acknowledges funding from the Canada Foundation for Innovation John R.Evans Leaders Fund(Project 35552)Ontario Research Fund—Research Infrastructure(Project 35552),the Waterloo Institute for Nanotechnology(WIN-NRC seed grant),and a Mitacs Globalink Research Award.
文摘This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS operating in air to provide a simple architecture for FC generators.A biased voltage signal drives the electrical resonator at resonance which is set to match an integer submultiple of twice the mechanical resonator’s resonance.Experimental results demonstrate that the NEMS displacement exhibit more than 150 equidistant peaks in the case of a 2:1 modal interaction and more than 60 equidistant peaks in the case of a 1:1 modal interaction.In both cases,the Free Spectral Range(FSR)was equal to the mechanical resonance frequency.Comparison between the FCs generated by the 2:1 and 1:1 modal interactions demonstrate the superiority of the former in terms of bandwidth and stability.The superior phase coherence of the FC generated via the 2:1 modal interaction was demonstrated via time-domain analysis.Our technique has the flexibility to generate multiple frequency combs and to fine-tune their FSR depending on the number of mechanical modes accessible to and the order of the activated modal interaction.It can be integrated into portable devices and is well aligned with modern miniaturization technology.
文摘Formal systems engineering approaches to modeling misperceptions and attitudes are employed within the framework of the graph model for conflict resolution to systematically study the War of 1812 between the United States of America and Great Britain in order to provide enhanced insights into the causes of the war. More specifically, relational definitions for preferences, movements and stability concepts are defined for describing the attitudes and associated behavior of decision makers involved in a conflict. To capture misperceptions of decision makers in the War of 1812, attitudes are studied within the structure of a hypergame. Combining attitudes and misperceptions within the paradigm of the graph model furnishes the flexible analytical tool which demonstrates that misunderstanding of attitudes by Great Britain and the United States may have contributed to the outbreak of this nasty war.
文摘Insightful theorems are established on interrelationships among coalition and noncooperative stability concepts defined within the paradigm of the Graph Model for Conflict Resolution. More specifically, the newly defined coalition stability def＇mitions that are considered are coalition Nash stability （CNash）, coalition general metarationality （CGMR）, coalition symmetric metarationality （CSMR） and coalition sequential stability （CSEQ）, along with their earlier-defined noncooperative versions. A range of interesting new theorems are derived to establish connections among these coalition stability concepts as well as between noncooperative and coalition stability definitions. Applications with respect to the games of Prisoner＇s Dilemma and Chicken, as well as a groundwater contamination dispute, demonstrate how the various stability definitions can be applied in practice and confirm the validity of some of the theorems as well as point out, by example, certain types of relationships which cannot hold.
文摘A comparison of two decision analysis tools for the analysis of strategic conflicts, the Analytic Network Process （ANP） and the graph model for conflict resolution, is carried out by applying them to the China-US TV dumping conflict. Firstly, the graph model is introduced along with practical procedures for modeling and analyzing conflicts using the decision support software, GMCR Ⅱ. Next, ANP is explained, emphasizing structural features and procedures for synthesizing priorities. Then a framework for employing ANP to analyze strategic conflicts is designed and used to compare ANP to the graph model. The case study of the China-US TV dumping conflict provides a basis for the graph model and ANP to be compared; different features of the approaches are highlighted. The study shows that because of different theoretical backgrounds, ANP and the graph model for conflict analysis both provide useful information which can be combined to furnish a better understanding of a strategic conflict.
