Robust Dichotomy Solution-Based Model Predictive Control for the Grid-Connected Inverters with Disturbance Observer

This paper proposes a robust dichotomy-based model predictive control(DS-MPC)with a fixed switching frequency for the grid-connected inverter(GCI).The proposed fast dichotomy algorithm can select and deduce the optimal voltage vector dynamically through the space vector plane.Therefore,the proposed DS-MPC strategy could ensure dynamic performance and steady-state performance as well.Also,the current control robustness can be improved through DS-MPC with disturbance observer(DO)based on the extended Kalman filter(EKF).The novelty of this control is that the current control with fast dynamic response can be realized in the weak grid,even if the grid voltages are greatly distorted.Simulation and hardware experiments on the weak grid validate the effectiveness of the proposed DS-MPC with the EKF observer approach.

Exponential Dichotomy and Eberlein-Weak Almost Periodic Solutions

We give sufficient conditions ensuring the existence and uniqueness of an Eberlein-weakly almost periodic solution to the following linear equation dx/dt(t) = A(t)x(t) + f(t) in a Banach space X, where (A(t)) t ∈□ is a family of infinitesimal generators such that for all t ∈□, A(t + T) = A(t) for some T > 0, for which the homogeneuous linear equation dx/dt(t) = A(t)x(t) is well posed, stable and has an exponential dichotomy, and f:□ →X is Eberlein-weakly amost periodic.

Quadratic Lyapunov Function and Exponential Dichotomy on Time Scales

In this paper, we study the relationship between exponential dichotomy and quadratic Lyapunov function for the linear equation x△=A（t）x on time scales. Moreover, for the nonlinear perturbed equation x△= A（t）x ＋ f（t, x） we give the instability of the zero solution when f is sufficiently small.

Pseudo Almost Automorphic Solutions for Non-autonomous Stochastic Differential Equations with Exponential Dichotomy

In this paper, we consider the existence and uniqueness of the solutions which are pseudo almost automorphic in distribution for a class of non-autonomous stochastic differential equations in a Hilbert space. In conclusion, we use the Banach contraction mapping principle and exponential dichotomy property to obtain our main results.

Plotting the Sequential Rock Remote Sensing Information by Optimization Dichotomy Method

The sequential rock remote sensing information is a group of rocks that are correlative in space or in space and time. For the sake of plottiug them, someone had brought forward the optimization segn.entotion metkod. We have ased this method to plot the sequential rock remote sensing information at tbe remote sensing hyperspetral test field of Daqing mountain, Inner Mongolia Autonomous Region, China, and found some disadvantages of this method. Therefore, we put forward the optimization dichotomy to plot them, and get better results. Finally we make a conclusion.

Nature and Culture Dualism： Genesis of an Obsolete Dichotomy

This paper will discuss the relation between the concepts of nature and culture and their intricate interdependency, focusing on modernity. Moreover, it will analyze the dichotomy that has historically emerged and its implications. Human beings have had different conceptions about what is natural and what is non-natural throughout their history. Before Modernity we did not conceive nature as being a different ontological reality, we did not perceive it as being separated from us. After modernity everything changed, and we began to see nature as a mere object. Nature became, then, a representation, like a painting on a wall. Our contemporary world vision, Weltanschauung, was formed mainly during the 16th and 17th centuries. There was, at that time, a considerable change in the way we perceived and described the world. This new mentality and this new form of representing the cosmos provided the basis for our new way of thinking. They were the substrate upon which our modern paradigm was erected. The world＇s conversion in an image only became a reality thanks to technology. But this change happened only because of the paradigm shift originated in the 17th century. Technique always has been a way to articulate how （and what） we think. With the Greek, technique （technd） was, at first, an extension of the physis. Thus, the technique was a way of being instead of a way of thinking. After the paradigm shift in the 17th century （a metaphysical change, in the very way we connected to the world）, the human being left his former place. Perhaps would be even better if we talked about nature and culture as being as a hybrid. What, at the source, was natural, through the flows of production and consumption, undergoes transformations and becomes something that is not natural anymore but, at the same time, not completely artificial either. Our world, once divided between the social and the natural, becomes a space where a constant process, a continuous flow, is constantly happening. From that dichotomy between something good and something bad arises a dialectic, in which we no longer can see any division whatsoever.

Wildean Ambivalent Dichotomy of Women--Taking An Ideal Husband as An Example

Oscar Wilde is mainly famous for being the representative figure of Aesthetic Movement and the steadfast advocate of"art for art's sake". Although being influenced by the traditional dichotomy of women, Wilde does try to add some personal elements during this process. In one of his social comedies, An Ideal Husband, this wildean characteristic is more obvious. This essay attempts to reveal those hidden images which are employed by Wilde to represent his female characters and tries to show the Wilde's improvement of the traditional dichotomy.

A GENERALIZATION OF A PROPOSITION ON EXPONENTIAL DICHOTOMY

It is well known that if x' = A(t)x admits an exponential dichotomy and f(t, x) is a bounded function and has a small Lipschitz constant, then system X' = A(x)x + f(t, x) has a unique bounded solution. In this paper, we shall generalize this theorem to the case when f(t, x) is an unbounded function.

On the Dichotomy of the Elegant and the Popular

The theoretical dichotomy of the elegant(ya) and the popular or common(su) has a long history and many branches, provoking Babel-like confusion of tongues. Both have their own aesthetic origins, and each is interpreted in relation to sociological categories such as social class and social strata. No abstract and absolute definition of the two concepts exists.The yayue(formal ceremonial music) of ancient China is an important early example of the elegant or refined, whereas the popular usually prevails at the lower levels of mass society.In the course of history, the accumulation of professional knowledge, selected classics, avant garde “art for art’s sake,” and leisure class activities have often been considered “elegant,”while the experience of the masses, folk revelry, and the content of mass media have been considered “popular.” In modern literary history, the concepts of enlightenment and class were drawn into the dichotomy of the elegant and the popular in different ways. In Chinese culture in the second half of the twentieth century, this dichotomy began to be reorganized around the notions of “art” and “commodity.” The reconceptualization of elegance and popularity at each stage of history has often indicated a reconnection between aesthetic tastes and history. In this sense, the differentiation of elegance and popularity has always testified to culture’s participation in history.

L_p-DICHOTOMY OF LINEAR DIFFERENTIAL EQUATIONS IN AN ARBITRARY BANACH SPACE

The notion of Lp-dichotomy for linear differential equations with possibly unbounded oper-ator is introduced. By help of Banach fixed point theorem sufficient conditions for the existenceof bounded solutions of nonlinear differential equations with an Lp-dichotomous linear part areobtained.

TOPOLOGICAL EQUIVALENCE FOR RECURRENT LINEAR SYSTEM WITH EXPONENTIAL DICHOTOMY

In this paper we discuss the recurrent linear system with exponential dichotomy, and prove that the system is topologically equivalent to the standard system where .

PERIODIC SOLUTIONS TO A KIND OF NEUTRAL DIFFERENTIAL SYSTEM:VIA (h,k)-DICHOTOMY

In this paper, based on the theory of (h, k)-Dichotomy of linear system and Kras-noselskii’s fixed point theorem, we study the existence of periodic solutions to a neutral differential equation. Some new sufficient conditions are obtained to guarantee the existence and uniqueness of T-periodic solution to the equation.

页岩气水平井分布式光纤温度监测高效反演解释方法

为突破页岩气水平井产出剖面和有效人工裂缝参数快速智能评价技术瓶颈,采用improved dichotomy(ID)算法建立页岩气水平井分布式光纤温度监测(DTS)数据反演模型,实现页岩气水平井产出剖面和每一簇有效人工裂缝参数的高效定量解释,最终形成页岩气水平井分布式光纤温度监测高效反演解释方法。对1口现场页岩气水平井的实测DTS数据进行解释分析,根据DTS数据识别诊断出69条有效人工裂缝。裂缝半长解释结果表明:该井裂缝扩展延伸极为不均,平均有效支撑裂缝半长为61.21 m,部分压裂段内存在明显的优势裂缝,裂缝半长大于120 m;反演模拟的温度剖面与实测DTS数据拟合较好,产出剖面反演解释结果与现场PLT测试产量较为吻合,单压裂段流量最大偏差仅为0.096×10^(4)m^(3)/d,验证了反演解释方法的可靠性。

Modeling and small-signal stability analysis of doubly-fed induction generator integrated system

Owing to their stability,doubly-fed induction generator(DFIG)integrated systems have gained considerable interest and are the most widely implemented type of wind turbines and due to the increasing escalation of the wind generation penetration rate in power systems.In this study,we investigate a DFIG integrated system comprising four modules:(1)a wind turbine that considers the maximum power point tracking and pitch-angle control,(2)induction generator,(3)rotor/grid-side converter with the corresponding control strategy,and(4)AC power grid.The detailed small-signal modeling of the entire system is performed by linearizing the dynamic characteristic equation at the steady-state value.Furthermore,a dichotomy method is proposed based on the maximum eigenvalue real part function to obtain the critical value of the parameters.Root-locus analysis is employed to analyze the impact of changes in the phase-locked loop,short-circuit ratio,and blade inertia on the system stability.Lastly,the accuracy of the small-signal model and the real and imaginary parts of the calculated dominant poles in the theoretical analysis are verified using PSCAD/EMTDC.

Zeno’s Paradoxes and Lie Tzu’s Dichotomic Wisdom Explained with Alpha Beta (αβ) Asymptotic Nonlinear Math (Including One Example on Second Order Nonlinear Phenomena)

Zeno’s paradoxes are a set of philosophical problems that were first introduced by the ancient Greek philosopher Zeno of Elea. Here is the first attempt to use asymptotic approach and nonlinear concepts to address the paradoxes. Among the paradoxes, two of the most famous ones are Zeno’s Room Walk and Zeno’s Achilles. Lie Tsu’s pole halving dichotomy is also discussed in relation to these paradoxes. These paradoxes are first-order nonlinear phenomena, and we expressed them with the concepts of linear and nonlinear variables. In the new nonlinear concepts, variables are classified as either linear or nonlinear. Changes in linear variables are simple changes, while changes in nonlinear variables are nonlinear changes relative to their asymptotes. Continuous asymptotic curves are used to describe and derive the equations for expressing the relationship between two variables. For example, in Zeno’s Room Walk, the equations and curves for a person to walk from the initial wall towards the other wall are different from the equations and curves for a person to walk from the other wall towards the initial wall. One walk has a convex asymptotic curve with a nonlinear equation having two asymptotes, while the other walk has a concave asymptotic curve with a nonlinear equation having a finite starting number and a bottom asymptote. Interestingly, they have the same straight-line expression in a proportionality graph. The Appendix of this discussion includes an example of a second-order nonlinear phenomenon. .

Comparative Analysis of Fractional Vegetation Cover Estimation Based on Multi-sensor Data in a Semi-arid Sandy Area

The estimation of fractional vegetation cover(FVC) is important for identifying and monitoring desertification, especially in arid and semiarid regions. By using regression and pixel dichotomy models, we present the comparison of Sentinel-2A(S2) multispectral instrument(MSI) and Landsat 8(L8) operational land imager(OLI) data regarding the retrieval of FVC in a semi-arid sandy area(Mu Us Sandland, China, in August 2016). A combination of unmanned aerial vehicle(UAV) high-spatial-resolution images and field plots were used to produce verified data. Based on a normalized difference vegetation index(NDVI) regression model, the results showed that, compared with that of L8, the coefficient of determination(R2) of S2 increased by 26.0%, and the root mean square error(RMSE) and the sum of absolute error(SAE) decreased by 3.0% and 11.4%, respectively. For the ratio vegetation index(RVI) regression model, compared with that of L8, the R2 of S2 increased by 26.0%, and the RMSE and SAE decreased by 8.0% and 20.0%, respectively. When the pixel dichotomy model was used, compared with that of L8, the RMSE of S2 decreased by 21.3%, and the SAE decreased by 26.9%. Overall, S2 performed better than L8 in terms of FVC inversion. Additionally, in this paper, we develop a verified scheme based on UAV data in combination with the object-based classification method. This scheme is feasible and sufficiently robust for building relationships between field data and inversion results from satellite data. Further, the synergy of multi-source sensors(especially UAVs and satellites) is a potential effective way to estimate and evaluate regional ecological environmental parameters(FVC).

Nonlinear Optimization Method of Ship Floating Condition Calculation in Wave Based on Vector

Ship floating condition in regular waves is calculated. New equations controlling any ship＇s floating condition are proposed by use of the vector operation. This form is a nonlinear optimization problem which can be solved using the penalty function method with constant coefficients. And the solving process is accelerated by dichotomy. During the solving process, the ship＇s displacement and buoyant centre have been calculated by the integration of the ship surface according to the waterline. The ship surface is described using an accumulative chord length theory in order to determine the displacement, the buoyancy center and the waterline. The draught forming the waterline at each station can be found out by calculating the intersection of the ship surface and the wave surface. The results of an example indicate that this method is exact and efficient. It can calculate the ship floating condition in regular waves as well as simplify the calculation and improve the computational efficiency and the precision of results.

ON THE ASYMPTOTICAL BEHAVIOUR OF SOLUTIONS OF A CLASS OF NONLINEAR CONTROL SYSTEMS

In this paper, the asymptotical behaviour solutions of a class of nonlinear control systems are studied. By establishing infinite integrals along solutions of the system and drawing support from a LaSalle's invariance principle of integral form, criteria of dichotomy and global asymptotical behaviour of solutions are obtained. This work is an improvement and further extension of research methods and results of A. S. Aisagaliev.

A Comprehensive Overview on Various Mind-Body Models

To understand what the relation between the mind and body is,philosophers and scientists have done quite a lot of work,but their opinions are controversial and this problem is known as mind-body dichotomy.Mind and body are thought to be separated in ancient Greek and ancient India and both of the two civilizations emphasize the dominated role of mind in the mind-body interaction.However,modern sciences such as biology are based on materialism and they think that mental phenomena are entirely dependent upon brain.A series of philosophical groups focusing on the mind-body problem,such as physicalism and dualism,have been developed based on traditional views and scientific advances.In this paper,a comprehensive overview and comparison to various theoretical mind-body models are carried out and based on the relativity of simultaneity axiom we recently proposed,we concluded that mind and body should be two independent existences and any theory based on monist philosophy such as materialism,idealism and Christianity cannot satisfy the logical consistency requirement while the trialism of matter,energy and information is unnecessary.

An Approximation Method of NURBS Curves in NC Machining

An algorithm for approximating arbitrary NURBS curve with straight line is presented.Firstly,NURBS curve is acquired according to data points on the curve.Secondly,Approximating arbitrary NURBS curve is based on dichotomy.The resulting straight line approaches to the original curve with relatively fewer segments within the required tolerance.The example shows that the algorithm is simple and its approximation precision is high.The method is most useful in numerical control to drive the cutter along straight line or circular paths.