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Desired Dynamic Equation for Primary Frequency Modulation Control of Gas Turbines
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作者 Aimin Gao Xiaobo Cui +2 位作者 Guoqiang Yu Jianjun Shu Tianhai Zhang 《Energy Engineering》 EI 2024年第5期1347-1361,共15页
Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency cont... Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential. 展开更多
关键词 Gas turbine primary frequency modulation(PFM) desired dynamic equation(DDE) proportion-integral(PI)
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Inverse Design of Phononic Crystal with Desired Transmission via a Gradient-Descent Approach
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作者 魏宇航 贺达海 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第9期14-18,共5页
We propose a general approach based on the gradient descent method to study the inverse problem,making it possible to reversely engineer the microscopic configurations of materials that exhibit desired macroscopic pro... We propose a general approach based on the gradient descent method to study the inverse problem,making it possible to reversely engineer the microscopic configurations of materials that exhibit desired macroscopic properties.Particularly,we demonstrate its application by identifying the microscopic configurations within any given frequency range to achieve transparent phonon transport through one-dimensional harmonic lattices.Furthermore,we obtain the phonon transmission in terms of normal modes and find that the key to achieving phonon transparency or phonon blocking state lies in the ratio of the mode amplitudes at ends. 展开更多
关键词 PROPERTIES PHONON desired
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New Method for Confirming the Desired Safety Headway Distance and Desired Deceleration in ACC System 被引量:1
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作者 张景波 刘昭度 +1 位作者 宋明 齐志权 《Journal of Beijing Institute of Technology》 EI CAS 2005年第2期175-178,共4页
A new method of confirming the desired safety headway distance and desired deceleration is put forward according to the detected static or moving target and its simulation results in Matlab are also presented. The val... A new method of confirming the desired safety headway distance and desired deceleration is put forward according to the detected static or moving target and its simulation results in Matlab are also presented. The validity of the algorithm to calculate the reference speeds of both the ACC vehicle and the targeted car according to the vector quadrangle composed of the relative distance, the relative azimuth angle, the relative speeds of the vehicles has also been demonstrated through numerical example in Matlab. New laws to obtain the desired deceleration by estimating the braking force according to the vehicle analyses force equation are established too. 展开更多
关键词 adaptive cruiser control (ACC) desired safety headway distance desired deceleration reference speed
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A cellular automata traffic flow modeling of desired speed variability 被引量:7
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作者 K. Bentaleb K. Jetto +1 位作者 H. Ez-Zahraouy A. Benyoussef 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期574-577,共4页
The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maxima... The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maximal velocity. However, the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity. This is in good agreement with empirical results obtained by Lipshtat [Phys. Rev. E 79 066110 (2009)]. Furthermore, our numerical result demonstrates that at low density the satisfaction rate takes higher values, whereas the coefficient of variance is close to zero. The coefficient of variance increases with increasing density, while the satisfaction rate decreases to zero. Moreover, we have also shown that, at low density the coefficient variance depends strongly on the probability of overtaking. 展开更多
关键词 TRAFFIC celluar automata satisfaction coefficient desired speed
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A new coupled map car-following model considering drivers' steady desired speed 被引量:6
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作者 周桐 孙棣华 +1 位作者 李华民 刘卫宁 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第5期41-45,共5页
Based on the pioneering work of Konishi et al., in consideration of the influence of drivers' steady desired speed ef/ect on the traffic flow, we develop a new coupled map car-following model in the real world. By us... Based on the pioneering work of Konishi et al., in consideration of the influence of drivers' steady desired speed ef/ect on the traffic flow, we develop a new coupled map car-following model in the real world. By use of the control theory, the stability condition of our model is derived. The validity of the present theoretical scheme is verified via numerical simulation, confirming the correctness of our theoretical analysis. 展开更多
关键词 traffic flow traffic congestion coupled map car-following model steady desired speed effect
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Fuzzy neural network control of underwater vehicles based on desired state programming 被引量:6
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作者 LIANG Xiao LI Ye XU Yu-ru WAN Lei QIN Zai-bai 《Journal of Marine Science and Application》 2006年第3期1-4,共4页
Due to the nonlinearity and uncertainty, the precise control of underwater vehicles in some intelligent operations hasn’t been solved very well yet. A novel method of control based on desired state programming was pr... Due to the nonlinearity and uncertainty, the precise control of underwater vehicles in some intelligent operations hasn’t been solved very well yet. A novel method of control based on desired state programming was presented, which used the technique of fuzzy neural network. The structure of fuzzy neural network was constructed according to the moving characters and the back propagation algorithm was deduced. Simulation experiments were conducted on general detection remotely operated vehicle. The results show that there is a great improvement in response and precision over traditional control, and good robustness to the model’s uncertainty and external disturbance, which has theoretical and practical value. 展开更多
关键词 underwater vehicle motion control fuzzy neural network desired state programming
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Model of desired speed based on vehicle dynamic
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作者 郭伟伟 王武宏 +2 位作者 毛琰 熊辉 张巍汉 《Journal of Beijing Institute of Technology》 EI CAS 2012年第1期81-84,共4页
The desired speed will help the drivers control their driver behavior that could directly influences the traffic safety. This paper presents a basic definition of a driver' s desired speed, and analyzes the effects o... The desired speed will help the drivers control their driver behavior that could directly influences the traffic safety. This paper presents a basic definition of a driver' s desired speed, and analyzes the effects of road geometer parameter, driver behavior and vehicle performance on the desired speed. By setting the familiar horizontal curve as the research environment, the generating process of the desired speed was described. Then, combined with the desired trajectory, the effect of driver' s identification of vehicle dynamic on the desired speed was highlighted. Based on the vehicle dynamic theory, a desired speed model that consisted of the desired trajectory, the driver's experience and vehicle parameter was established and numerically analyzed. 展开更多
关键词 traffic safety DRIVER desired speed horizontal curve
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A New Method of Desired Gait Synthesis for Biped Walking Robot Based on Ground Reaction Force
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作者 张永学 《High Technology Letters》 EI CAS 2000年第4期33-38,共6页
A new method of desired gait synthesis for biped walking robot based on the ground reaction force was proposed. The relation between the ground reaction force and joint motion is derived using the D’Almbert principle... A new method of desired gait synthesis for biped walking robot based on the ground reaction force was proposed. The relation between the ground reaction force and joint motion is derived using the D’Almbert principle. In view of dynamic walking with high stability, the ZMP(Zero Moment Point)stability criterion must be considered in the desired gait synthesis. After that, the joint trajectories of biped walking robot are decided by substituting the ground reaction force into the aforesaid relation based on the ZMP criterion. The trajectory of desired ZMP is determined by a fuzzy logic based upon the body posture of biped walking robot. The proposed scheme is simulated and experimented on a 10 degree of freedom biped walking robot. The results indicate that the proposed method is feasible. 展开更多
关键词 BIPED WALKING robot desired GAIT SYNTHESIS ZMP Ground reaction force Fuzzy logic
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A desired landing points walking method enablinga planner quadruped robot to walk on rough terrain
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作者 MA Hongwen WANG Liquan ZHONG Zhi YAO Shaoming 《智能系统学报》 2011年第5期464-469,共6页
It is necessary for legged robots to walk stably and smoothly on rough terrain.In this paper,a desired landing points(DLP) walking method based on preview control was proposed in which an off-line foot motion trace an... It is necessary for legged robots to walk stably and smoothly on rough terrain.In this paper,a desired landing points(DLP) walking method based on preview control was proposed in which an off-line foot motion trace and an on-line modification of the trace were used to enable the robot to walk on rough terrain.The on-line modification was composed of speed modification,foot lifting-off height modification,step length modification,and identification and avoidance of unsuitable landing terrain.A planner quadruped robot simulator was used to apply the DLP walking method.The correctness of the method was proven by a series of simulations using the Adams and Simulink. 展开更多
关键词 legged robot preview control desired landing points planner quadruped robot
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Efficient Method to Achieve Enhanced Thermal Dimensional Stability and Desired Dimensions of Hollow Polyester Fiber
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作者 刘奎 周晖 +3 位作者 章倩 孙宝忠 张瑞云 黄莉茜 《Journal of Donghua University(English Edition)》 EI CAS 2016年第4期670-672,共3页
This study has developed an efficient method to achieve excellent thermal dimensional stability and desired dimensions of hollow polyester fiber. Firstly,the influence of thermal treatment temperate( 140-180 ℃) on th... This study has developed an efficient method to achieve excellent thermal dimensional stability and desired dimensions of hollow polyester fiber. Firstly,the influence of thermal treatment temperate( 140-180 ℃) on the degree of shrinkage of fiber was investigated. The influence was also analyzed with a 2nd heating to simulate the application situation. It was discovered that the heat treatment at a temperature which was above the application temperature( 2nd heating) would efficiently remove the internal stress in the fiber and improve the thermal dimensional stability.Secondly,the impact of heat treatment temperature on the fiber diameter and the degree of hollowness were studied. The results implied that with a fixed fiber length, higher treatment temperature led to thinner fiber and a lower degree of hollowness.Last but not least,key parameters that could further influence the fiber dimensions were investigated. The results suggested that the fiber diameters and the degree of hollowness could be further controlled by tuning the drawing speed,the spinning meter pump output and cooling status while the spinneret parameters were fixed. 展开更多
关键词 hollow diameters heating shrinkage desired dimensions spinning polyester length thinner
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A Novel Approach for Trajectory Tracking Control of an Under-Actuated Quad-Rotor UAV
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作者 Ke Shao Kang Huang +2 位作者 Shengchao Zhen Hao Sun Rongrong Yu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第9期2030-2032,共3页
Dear Editor,This letter presents a novel Udwadia-Kalaba(U-K)approach for the trajectory tracking control of a quad-rotor unmanned aerial vehicle(UAV).Compared to conventional control approaches,the desired trajectorie... Dear Editor,This letter presents a novel Udwadia-Kalaba(U-K)approach for the trajectory tracking control of a quad-rotor unmanned aerial vehicle(UAV).Compared to conventional control approaches,the desired trajectories are treated as trajectory tracking constraints in this approach. 展开更多
关键词 LETTER desired CONSTRAINTS
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The 2018 Nobel Prize in Chemistry: Engineering proteins(enzymes/peptide/antibodies) towards desired properties via the construction of random libraries 被引量:1
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作者 Zengyi Chang 《Science China(Life Sciences)》 SCIE CAS CSCD 2019年第5期713-724,共12页
The 2018 Nobel Prize in Chemistry was awarded one half to Dr. Frances Arnold (of California Institute of Technology,USA) for her work on 'directed evolution of enzymes', the other half to Dr. George Smith (of ... The 2018 Nobel Prize in Chemistry was awarded one half to Dr. Frances Arnold (of California Institute of Technology,USA) for her work on 'directed evolution of enzymes', the other half to Dr. George Smith (of the University of Missouri, USA) and Sir Gregory Winter (of MRC Laboratory of Molecular Biology, UK) for their work on 'phage display of peptides and antibodies'. 展开更多
关键词 The 2018 Nobel Prize in Chemistry TOWARDS desired properties via the construction of RANDOM LIBRARIES ENGINEERING PROTEINS
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Optimization and Characterization of Combined Degumming Process of Typha angustata L. Stem Fibers
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作者 Sana Rezig Foued Khoffi +2 位作者 Mounir Jaouadi Asma Eloudiani Slah Msahli 《Journal of Renewable Materials》 EI CAS 2024年第6期1071-1086,共16页
Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to... Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%). 展开更多
关键词 Typha angustata L.stems fibers combined treatment optimization process desirability function chemical and physical properties morphological structure
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拉美亟待破解转型困局
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作者 杨首国 严谨 吕洋 《Contemporary International Relations》 2024年第1期109-117,共9页
In 2023, Latin America was confronted with increased domestic and international challenges, resulting in a stronger public desire for change. New social ideologies are continuing to emerge, and transformation through ... In 2023, Latin America was confronted with increased domestic and international challenges, resulting in a stronger public desire for change. New social ideologies are continuing to emerge, and transformation through reform has become a broad consensus. However, during the complicated reshaping of Latin America's political ecology, the swing of the political pendulum and the change of regimes are accelerating. 展开更多
关键词 LATIN POLITICAL desire
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PATH PROBLEM SIMPLIFICATION WITH DESIRED BOUNDED LENGTHS IN ACYCLIC NETWORKS
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作者 Zhixiong Su Jianxun Qi Hanying Wei 《Journal of Systems Science and Systems Engineering》 SCIE EI CSCD 2015年第4期500-519,共20页
Path determination is a fundamental problem of operations research. Current solutions mainly focus on the shortest and longest paths. We consider a more generalized problem; specifically, we consider the path problem ... Path determination is a fundamental problem of operations research. Current solutions mainly focus on the shortest and longest paths. We consider a more generalized problem; specifically, we consider the path problem with desired bounded lengths (DBL path problem). This problem has extensive applications; however, this problem is much harder, especially for large-scale problems. An effective approach to this problem is equivalent simplification. We focus on simplifying the problem in acyclic networks and creating a path length model that simplifies relationships between various path lengths. Based on this model, we design polynomial algorithms to compute the shortest, longest, second shortest, and second longest paths that traverse any arc. Furthermore, we design a polynomial algorithm for the equivalent simplification of the is O(m), where m is the number of arcs. DBL path problem. The complexity of the algorithm 展开更多
关键词 Operations research path problem with desired bounded lengths equivalent simplification path length model acyclic network
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Dynamic Event-Triggered Control of Continuous-Time Systems With Random Impulses 被引量:1
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作者 Meng Yao Guoliang Wei 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第12期2292-2299,共8页
In this paper,the networked control problem under event-triggered schemes is considered for a class of continuoustime linear systems with random impulses.In order to save communication costs and lighten communication ... In this paper,the networked control problem under event-triggered schemes is considered for a class of continuoustime linear systems with random impulses.In order to save communication costs and lighten communication burden,a dynamic event-triggered scheme whose threshold parameter is dynamically adjusted by a given evolutionary rule,is employed to manage the transmission of data packets.Moreover,the evolution of the threshold parameter only depends on the sampled measurement output,and hence eliminates the influence of impulsive signals on the event-triggered mechanism.Then,with the help of a stochastic analysis method and Lyapunov theory,the existence conditions of desired controller gains are received to guarantee the corresponding input-to-state stability of the addressed system.Furthermore,according to the semi-definite programming property,the desired controller gains are calculated by resorting to the solution of three linear matrix inequalities.In the end,the feasibility and validity of the developed control strategy are verified by a simulation example. 展开更多
关键词 mechanism. desired hence
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An effective array beamforming scheme based on branch-and-bound algorithm
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作者 YE Xiaodong LI Li +1 位作者 WANG Hao TAO Shifei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第6期1483-1489,共7页
In this paper, we propose an effective full array and sparse array adaptive beamforming scheme that can be applied for multiple desired signals based on the branch-and-bound algorithm. Adaptive beamforming for the mul... In this paper, we propose an effective full array and sparse array adaptive beamforming scheme that can be applied for multiple desired signals based on the branch-and-bound algorithm. Adaptive beamforming for the multiple desired signals is realized by the improved Capon method. At the same time,the sidelobe constraint is added to reduce the sidelobe level. To reduce the pointing errors of multiple desired signals, the array response phase of the desired signal is firstly optimized by using auxilary variables while keeping the response amplitude unchanged. The whole design is formulated as a convex optimization problem solved by the branch-and-bound algorithm. In addition,the beamformer weight vector is penalized with the modified reweighted l_(1)-norm to achieve sparsity. Theoretical analysis and simulation results show that the proposed algorithm has lower sidelobe level, higher SINR, and less pointing error than the stateof-the-art methods in the case of a single expected signal and multiple desired signals. 展开更多
关键词 multiple desired signal auxiliary variable branchand-bound algorithm reweighted-norm.
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New Adaptive Cruise Control Method 被引量:4
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作者 卢江 刘昭度 +1 位作者 时开斌 安巍 《Journal of Beijing Institute of Technology》 EI CAS 2000年第4期428-433,共6页
A new adaptive cruise control (ACC) method based on the desired safety headway distance is investigated for improving the vehicle traffic safety at high speed by regulating the additional throttle opening and braking ... A new adaptive cruise control (ACC) method based on the desired safety headway distance is investigated for improving the vehicle traffic safety at high speed by regulating the additional throttle opening and braking torque of driving wheels only. The selection of headway distance sensors, the determination of desired safety headway distance and desired deceleration are elaborated. The ACC flowchart and simulation, as well as signal misinformation and its resolutions are described. The simulation proves that the new ACC method is simpler and feasible. The new method is easily integrated ACC with ABS/ASR to form an organic ABS/ASR/ACC system. 展开更多
关键词 adaptive cruise control(ACC) desired deceleration desired safety headway distance SIMULATION
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Fly Ash and Slag as Partial Replacement of Cement for the Synthesis of Low Carbon Cementitious Materials
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作者 Yafei Hu Keqing Li +1 位作者 Lujing Zheng Bin Han 《Journal of Renewable Materials》 SCIE EI 2023年第5期2491-2511,共21页
Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings res... Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings results in a large consumption of traditional cement as a cementitious material and insignificant improvement in strength.Therefore,a composite cementitious system of cement and solid waste resources(fly ash and slag powder)is explored for this study.In this paper,the response surface methodology(RSM)is used to optimize the experimental design and a multivariate nonlinear response model with cement,fly ash and slag powder contents as variables are constructed,which can investigate the effect of the composite cementitious system on the strength of tailing wet shotcrete(TWSC).In addition,the information entropy(IE)is introduced and combined with the RSM to evaluate the composite cementitious system.Finally,the desirability function(DF)combined with RSM is used to optimize the composite cementitious system.The results show that the response model constructed in this paper has R^(2)=0.96 and P-value<0.01(the test result of the model is P-value<0.01),which indicates that the model has high reliability.The higher the content of slag powder and cement in the composite cementitious system,the higher the strength and comprehensive score of the TWSC.There is a critical value of fly ash content,which makes the maximum cementation of the composite cementing system.The optimal mix proportion of the composite cementitious system is obtained based on RSM-DF,which leads to the strength of TWSC at different curing time to achieve the expected index. 展开更多
关键词 TAILINGS wet shotcrete composite cementitious system desirability function mix proportion optimization
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Extension of Goal-Directed Behavior Model for Post-Pandemic Korean Travel Intentions to Alternative Local Destinations: Perceived Risk and Knowledge
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作者 Heesup Han Hong Ngoc Nguyen +1 位作者 Hyerin Lee Sanghyeop Lee 《International Journal of Mental Health Promotion》 2023年第4期449-469,共21页
Since the outbreak of COVID-19,tourists have been increasingly concerned over various risks of international travel,while knowledge of the pandemic appears to vary significantly.In addition,as travel restrictions cont... Since the outbreak of COVID-19,tourists have been increasingly concerned over various risks of international travel,while knowledge of the pandemic appears to vary significantly.In addition,as travel restrictions continue to impact adversely on international tourism,tourism efforts should be placed more on the domestic markets.Via structural equation modeling,this study unearthed different risk factors impacting Korean travelers’choices of alternative local destinations in the post-pandemic era.In addition,this study extended the goal-directed behavior framework with the acquisition of perceived risk and knowledge of COVID-19,which was proven to hold a sig-nificantly superior explanatory power of tourists’decisions of local alternatives over foreign countries during the COVID-19 pandemic.Furthermore,desire was found to play an imminent mediating role in the conceptual mod-el,maximizing the impact of perceived risk on travel intentions.Henceforth,this research offers meaningful the-oretical implication as thefirst empirical study to deepen the goal-directed behaviour framework with perceived risk and knowledge in the context of post-COVID-19 era.It also serves as insightful knowledge for Korean tour-ism authorities and practitioners to understand local tourists’decision-making processes and tailor effective recovery strategy for domestic tourism. 展开更多
关键词 Travel intention goal-directed behavior desire perceived risk COVID-19 domestic tourism Korean tourists
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