Desired Dynamic Equation for Primary Frequency Modulation Control of Gas Turbines

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.

Inverse Design of Phononic Crystal with Desired Transmission via a Gradient-Descent Approach

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.

New Method for Confirming the Desired Safety Headway Distance and Desired Deceleration in ACC System

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.

A cellular automata traffic flow modeling of desired speed variability

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.

A new coupled map car-following model considering drivers' steady desired speed

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.

Model of desired speed based on vehicle dynamic

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.

A New Method of Desired Gait Synthesis for Biped Walking Robot Based on Ground Reaction Force

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.

A desired landing points walking method enablinga planner quadruped robot to walk on rough terrain

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.

The 2018 Nobel Prize in Chemistry: Engineering proteins(enzymes/peptide/antibodies) towards desired properties via the construction of random libraries

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'.

拉美亟待破解转型困局

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.

PATH PROBLEM SIMPLIFICATION WITH DESIRED BOUNDED LENGTHS IN ACYCLIC NETWORKS

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

An effective array beamforming scheme based on branch-and-bound algorithm

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.

Dynamic Event-Triggered Control of Continuous-Time Systems With Random Impulses

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.

Fly Ash and Slag as Partial Replacement of Cement for the Synthesis of Low Carbon Cementitious Materials

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.

Extension of Goal-Directed Behavior Model for Post-Pandemic Korean Travel Intentions to Alternative Local Destinations: Perceived Risk and Knowledge

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.

On Laozi’s View of Desire

Laozi’s concept of desire has rich ideological connotations,not only referring to reducing personal desires.Laozi’s concept of desire is based on“desire”as human nature,acknowledging the legitimacy and necessity of desire and demand.The rational criticism of“having desire”formed by“no desire”is the value pursuit of Laozi’s concept of desire.From both personal physical and mental aspects and social order,“no desire”plays an important guiding role.Nature is the essence of Laozi’s concept of desire,and being in harmony with nature is the best state of desire.Laozi’s concept of desire reveals a deep spirit of love,and the“ethics of love”highlights Laozi’s strong sense of care for the“other”and ethical attitude towards responsibility.Laozi’s contemplation of desire contains a strong humanistic spirit,with the aim of promoting the healthy and sustainable development of life and society.

Social Determinants of Social Zapping:Exploring Predictors of Planned Scheduled Social Events with Others

Social zapping has gained popularity as a term that refers to canceling plans or appointments at the last minute to attend other,supposedly more appealing events.This behavior resembles rapidly switching channels on a television,as individuals frequently jump between different social engagements.The present study examined potential behavioral trait predictors of social zapping,such as belongingness,self-esteem,sense of control,and meaningful existence among community residents ranging from 40 to 75 years of age(n=48).The study utilized simple linear regressions to identify potential predictors of social zapping,exploring how the four fundamental needs(belongingness,self-esteem,sense of control,and meaningful existence)might be linked.Results indicated that belongingness and self-esteem are significant predictors of social zapping tendencies.Additionally,an independent samples t-test was conducted to determine the relationship both older and younger adults have with the four fundamental needs as well as the role age plays in social zapping tendencies.Older adults exhibited a significant and more positive association with self-esteem,sense of control,and meaningful existence compared to individuals aged 39 and younger.Social zapping frequency was nonsignificant for both older adults and younger adults.Furthermore,a separate set of linear regression analyses were completed to determine how social desirability affects social zapping across age groups.Social desirability significantly predicted both self-esteem and meaningful existence.Overall,the present study builds on what is currently a new phenomenon in research and will provide new information on the relationship between age,social zapping,and behavioral traits.

《英语词汇学》辅导(5)

Ⅰ.Each of the statements below is followed by four alternative answers.Choose the one that wouldbest complete the statement.1.Polysemy is a common feature peculiar to ___.A.English only B.Chinese only C.all natural languages D.some natural languages2.From the ____ point of view,polysemy is assumed to be the result of growth and development of thesemantic structure of one and same word.A.linguistic B.diachronic C.synchronic D.

基于Desirability函数法对米根霉发酵制备富马酸的多目标优化

以富马酸产量和生产速率为目标,通过正交实验考察了种龄、接种量、葡萄糖和尿素浓度对两者的影响,进一步利用基于响应曲面方法的Desirability函数确定了葡萄糖和尿素的最佳浓度。结果表明,最佳的种龄和接种量分别为36h和15%(v/v),葡萄糖和尿素的优化浓度为132.73和0.0586g/L,此时模型预测的富马酸产量和生产速率达到71.42g/L和0.804g/(l.h),Desirability的函数值高达0.966。该条件下在5L发酵罐水平上进行验证试验,经过88h的发酵最终生成富马酸66.5g/L,生产速率达到0.755g/(l.h),与未优化前相比,产量和生产速率分别提高了13.9%和15.8%,取得了理想的效果,实现了产量和生产速率的同时优化,为发酵法制备富马酸的工业化放大奠定了基础。

FKAOS:一种面向Agent需求工程方法

面向Agent需求工程重点研究软件系统的面向Agent的抽象组织形式 .本文提出一种新的面向Agent需求工程方法———FKAOS方法 .该方法作为较高抽象程度的以Agent为核心的软件系统描述方法能辅助用户和系统设计人员更好地分析和设计系统需求 .FKAOS方法通过引入FuzzyZ语言 ,扩展经典的KAOS方法 ,描述多Agent系统中的非确定需求问题 .FKAOS方法中的描述视图引入了KAOS方法的目标和责任视图 ,并添加了一些新的专门描述面向Agent的需求问题的视图和表 .本文重点介绍了FKAOS方法的基本元模型概念和相关的主要视图描述模型等内容 。