2-D Modeling and Calculations of Stratospheric Ozone and Influences of Convection, Diffusion, and Time

An engineering system approach of 2-D cylindrical model of transient mass balance calculations of ozone and other concerned chemicals along with fourteen photolysis, ozone-generating and ozone-depleting chemical reaction equations was developed, validated, and used for studying the ozone concentrations, distribution and peak of the layer, ozone depletion and total ozone abundance in the stratosphere. The calculated ozone concentrations and profile at both the Equator and a 60˚N location were found to follow closely with the measured data. The calculated average ozone concentration was within 1% of the measured average, and the deviation of ozone profiles was within 14%. The monthly evolution of stratospheric ozone concentrations and distribution above the Equator was studied with results discussed in details. The influences of slow air movement in both altitudinal and radial directions on ozone concentrations and profile in the stratosphere were explored and discussed. Parametric studies of the influences of gas diffusivities of ozone DO3 and active atomic oxygen DO on ozone concentrations and distributions were also studied and delineated. Having both influences through physical diffusion and chemical reactions, the diffusivity (and diffusion) of atomic oxygen DO was found to be more sensitive and important than that of ozone DO3 on ozone concentrations and distribution. The 2-D ozone model present in this paper for stratospheric ozone and its layer and depletion is shown to be robust, convenient, efficient, and executable for analyzing the complex ozone phenomena in the stratosphere. .

Calculations and Sensitivity Analysis of Chlorine-,NO_(x)-,and Bromine-Depleting Cycles of Stratospheric Ozone

This paper presents an engineering system approach using a 2D model of conservation of mass to study the dynamics of ozone and concerned chemical species in the stratosphere.By considering all fourteen photolysis,ozone-generating,and-depleting chemical reactions,the model calculated the transient,spatial changes of ozone under different physical-chemical-radiative conditions.Validation against the measured data demonstrated good accuracy,close match of our model with the observed ozone concentrations at both 20°S and 90°N locations.The deviation in the average concentration was less than 1% and in ozone profiles less than 17%.The impacts of various chlorine-(Cl),nitrogen oxides-(NO_(x)),and bromine-(Br)depleting cycles on ozone concentrations and distribution were investigated.The chlorine catalytic depleting cycle was found to exhibit the most significant impact on ozone dynamics,confirming the key role of chlorine in the problem of ozone depletion.Sensitivity analysis was conducted with levels of 25%,50%,100%,200%,and 400% of the baseline value.The combined cycles(Cl+NO_(x)+Br)showed the most significant influence on ozone behavior.The total ozone abundance above the South Pole could decrease by a small 3%,from 281 DU(Dubson Units)to 273 DU for the 25% level,or by a huge thinning of 60%to 114 DU for the 400% concentration level.When the level of chlorine gases increased beyond 200%,it would cause ozone depletion to a level of ozone hole(below 220 DU).The 2D Ozone Model presented in this paper demonstrates robustness,convenience,efficiency,and executability for analyzing complex ozone phenomena in the stratosphere.

Interannual variability of carbon cycle implied by a 2-D atmospheric transport model

A 2-dimensional atmospheric transport model is deployed in a simplified CO 2 inverse study. Calculated carbon flux distribution for the interval from 1981 to 1997 confirms the existence of a terrestrial carbon sink in mid-high latitude area of North Hemisphere. Strong interannual variability exists in carbon flux patterns, implying a possible link with ENSO and other natural episodes such as Pinatubo volcano eruption in 1991. Mechanism of this possible link was investigated with statistic method. Correlation analysis indicated that in North Hemisphere, climatic factors such as temperature and precipitation, to some extend, could influence the carbon cycle process of land and ocean, thus cause considerable change in carbon flux distribution. In addition, correlation study also demonstrated the possible important role of Asian terrestrial ecosystems in carbon cycle.

A 2-D Non-local Closure Model for Atmospheric Boundary Layer Simulations

In this paper a new approach for PBL simulation, the non-local closure scheme based on the transient turbulence theory has been used. It was set up as an alternative to local closure schemes which physical concept is reasonable and distinct. A 2-D non-local closure model was developed in order to study the PBL structure and simulatesome interesting atmospheric processes over non-ulliform underlying surface, especially under the convective and unique weather conditions, such as sea-land circulation and the TIBL structure. The modelled results show good agreement with field measurement.

Kalman Filter for Generalized 2-D Roesser Models

The design problem of the state filter for the generalized stochastic 2-D Roesser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The well-known Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of “scanning line by line”,the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.

A Survey on the Stability of 2-D Discrete Systems Described by Fornasini-Marchesini Second Model

A key issue of practical importance in the two-dimensional (2-D) discrete system is stability analysis. Linear state-space models describing 2-D discrete systems have been proposed by several researchers. A popular model, called Forna- sini-Marchesini (FM) second model was proposed by Fornasini and Marchesini in 1978. The aim of this paper is to present a survey of the existing literature on the stability of FM second model.

Robust Optimal H∞ Control for Uncertain 2-D Discrete State-Delayed Systems Described by the General Model

This paper investigates the problem of robust optimal H∞ control for uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model (GM) with norm-bounded uncertainties. A sufficient condition for the existence of g-suboptimal robust H∞ state feedback controllers is established, based on linear matrix inequality (LMI) approach. Moreover, a convex optimization problem is developed to design a robust optimal state feedback controller which minimizes the H∞ noise attenuation level of the resulting closed-loop system. Finally, two illustrative examples are given to demonstrate the effectiveness of the proposed method.

Delay-Dependent Robust H∞ Control for Uncertain 2-D Discrete State Delay Systems Described by the General Model

This paper considers the problem of delay-dependent robust optimal H∞ control for a class of uncertain two-dimensional (2-D) discrete state delay systems described by the general model (GM). The parameter uncertainties are assumed to be norm-bounded. A linear matrix inequality (LMI)-based sufficient condition for the existence of delay-dependent g-suboptimal state feedback robust H∞ controllers which guarantees not only the asymptotic stability of the closed-loop system, but also the H∞ noise attenuation g over all admissible parameter uncertainties is established. Furthermore, a convex optimization problem is formulated to design a delay-dependent state feedback robust optimal H∞ controller which minimizes the H∞ noise attenuation g of the closed-loop system. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed method.

Non-Fragile Controller Design for 2-D Discrete Uncertain Systems Described by the Roesser Model

This paper is concerned with the design problem of non-fragile controller for a class of two-dimensional (2-D) discrete uncertain systems described by the Roesser model. The parametric uncertainties are assumed to be norm-bounded. The aim of this paper is to design a memoryless non-fragile state feedback control law such that the closed-loop system is asymptotically stable for all admissible parameter uncertainties and controller gain variations. A new linear matrix inequality (LMI) based sufficient condition for the existence of such controllers is established. Finally, a numerical example is provided to illustrate the applicability of the proposed method.

基于2-D模型的人体运动跟踪

人体运动跟踪是图象处理和计算机视觉研究的热点问题 .它在人机接口、虚拟现实、智能监控、机器人仿真等方面具有广阔应用前景 ,已引起越来越多学者的关注 .为了实现准确的人体运动跟踪 ,采用了两种基于 2 D模型的人体运动跟踪方法 :其中 ,一种方法是以区域面积重合率为匹配准则 ,采用由粗到细的匹配过程 ,通过建立 2 D模型以实现与真实人体运动间的准确匹配 ;另一种是基于区域特征的 2 D模型和人体各个部位的连接关系 ,通过确定和标记人体的各个部位 ,最终由 2 D模型来重现真实人体的运动过程 .同时采用以上两种方法 ,对实际人体运动进行了跟踪测试 ,在全身运动的整个过程中能给出较为准确的跟踪结果 .表明该方法不仅能抵御噪声和灰度变化的影响 ,而且能大致估计出被遮挡部位的位置 .

广义2-D Roesser模型的状态滤波器

研究了状态和测量同时受白噪声干扰时广义随机2-D Roesser模型的状态滤波器设计问题。将Kalman滤波器的设计推广至广义2-D Roesser模型。通过逐行扫描法,模能重构的广义2-D Roesser模型的滤波问题得到了解决,获得了状态向量的最优滤波的计算公式。计算步骤和例子说明了设计的滤波器的有效性。

基于2-D系统理论的D型开闭环迭代学习控制

对于具有重复运动性质的系统,迭代学习控制是一种行之有效的控制方法。开闭环迭代学习控制能同时利用系统前次运行和当前运行的信息,因而性能优于单纯的开环迭代学习控制。针对线性连续系统,设计了D(Differential)型开闭环迭代学习控制器,利用2-D(Two-Dimensional)系统理论建立系统的2-D连续—离散Roesser模型,并给出了保证控制器收敛的充分必要条件。最后通过一个仿真实例,证明了该方案的有效性。

广义2-D系统Roesser模型的可接受输入序列研究

通过将有限矩形上的广义 2 - D Roesser模型转化为等价的代数方程 ,给出了有限矩形上所有输入均为该系统的可接受输入的充要条件 ;利用 2 - D Z-变换以及多项式矩阵的性质 ,给出了无限矩形上所有输入均可接受的充要条件。证明了当系统的输入矩阵行满秩时 ,只要系统在某个有限矩形上的所有输入均为可接受输入 ,则在无限矩形上的所有输入也均为可接受输入。基于矩阵的初等行变换 ,提出了确定广义 2 - D系统 Roesser模型可接受输入序列集合的方法。

球面2-DOF冗余驱动并联机器人机构误差分析

将环路增量法应用于多环路并联机构的误差分析中,并提出环路选取原则。基于D-H参数,结合冗余驱动机构特点,采用环路增量法,建立兼顾位置和姿态两类误差的球面2-DOF冗余驱动并联机器人机构误差模型。该误差模型除包含机构的结构参数误差外,同时还将由于加工和装配等原因出现的各转动副轴线和球心之间的偏差考虑进来,更全面地反映了机构的工程实际情况。基于该误差模型进一步分析球面机构出现卡死现象的原因,预估了机构误差,为该机构样机的运动学标定研究奠定了理论基础。

2-D系统H∞输出反馈迭代学习控制器设计

针对2-D线性离散系统设计迭代学习控制器。首先,给出描述参考轨迹、初始状态、外界干扰等迭代变化参数的高阶内模。然后,聚合这些高阶内模得到增广的高阶内模并构造一种新的迭代学习控制器。针对非零边界条件和干扰的2-D Roesser模型,利用2-D分析方法提出其渐近稳定性。建立了适用于零边界条件和非零边界条件的迭代学习控制律设计准则以实现完美跟踪和2-D H∞性能,并提出了基于高阶内模的H∞输出反馈迭代学习控制器。针对控制器的求解问题,提出了两种不同的解法。最后,对一个初始温度、外界干扰迭代变化的化学反应过程的数值计算,表明了所提出的2-D控制器设计方法的有效性。

一类带乘性噪声2-D奇异系统的滤波算法

针对一类带乘性噪声2-D奇异系统的Roesser模型,提出了一种状态滤波算法。该算法首先对无跳跃模的2-D奇异Roesser模型进行等价变换,变换为2个降阶的子系统,其中子系统一可继续变换为易于处理的动态噪声和量测噪声在同一坐标点相关的非奇异带乘性噪声FM-Ⅱ模型;然后基于正交投影定理,得到了带乘性噪声2-D奇异Roesser模型的状态滤波算法,同时得到了带乘性噪声2-D FM-Ⅱ模型的状态滤波算法。上述算法在线性最小方差意义下是最优的,仿真验证了算法的有效性。

2-D Roesser模型状态反馈特征结构配置

基于Sylvester矩阵方程的显示通解提出了上(下)块三角的状态反馈特征结构配置的参数化方法。给出了状态反馈控制律及闭环特征向量的参数化表达式,它们都依赖于参数向量{f1ijk}及{f2ijk},这组参数向量表征了系统的设计自由度,通过合理地选择这些自由度可以满足系统的其它性能指标,为系统的进一步设计提供了方便。数值例子显示了其有效性。

随机2-D系统的集员状态估计

本文研究了噪声在有界椭球集的2-DFMII模型的状态向量的递推估计问题。从提高计算的有效性和可实现性出发,通过在不同的更新阶段采用优化定界椭球(OBE)算法,对该系统提出了一种新的状态估计方法。所得状态估计是状态空间里一个集合而不是单个向量。其中的最优估计是包含系统未知状态的最小容积椭球。

2-D离散系统的输入-输出能量解耦

给出了2-D离散系统的能量解耦方法,即从输入-输出能量关系上对2-D离散系统进行解耦,使得任何一个输入的能量主要控制一个输出的能量。给出了2-D Roesser模型的能量解耦判据,并且用线性矩阵不等式来描述,求解方便。最后,给出了示例。

2-D连续-离散系统的平衡模型降阶

基于局部能达性与局部能观性的分析给出2-D连续-离散系统状态空间模型的平衡实现,这一实现的第i个状态分量的重要性由系统的能达、能观阵的第i个对角元素所度量,去掉平衡实现系统弱能达、弱能观的部分,从而得到2-D连续-离散系统的模型降阶。所给示例表明,该方法具有良好的降阶效果。