Effects of Nested Area Size upon Regional Climate Model Simulations

This paper presents a numerical study on the 1998 summer rainfall over the Yangtze River valley in central and eastern China, addressing effect of a nested area size on simulations in terms of the technique of nesting a regional climate model (RCM) upon a general circulation model (GCM). Evidence suggests that the size exerts greater impacts upon regional climate of the country, revealing that a larger nested size is superior to a small one for simulation in mitigating errors of GCM-provided lateral boundary forcing. Also, simulations show that the RCM should incorporate regions of climate systems of great importance into study and a low-resolution GCM yields more pronounced errors as a rule when used in the research of the Tibetan Plateau, and, in contrast, our PσRCM can do a good job in describing the plateau’s role in a more realistic and accurate way. It is for this reason that the tableland should be included in the nested area when the RCM is employed to investigate the regional climate. Our PσRCM nesting upon a GCM reaches more realistic results compared to a single GCM used.

A Regional Spectral Nested Multilevel Primitive Equation Model

By means of vertical normal modes a regional nested multilevel primitive equation model can be reduced to several sets of shallow water equations characterized by various equivalent depths. Therefore, time integration of the model in spectral form can be performed in the manner similar to those used in the spectral nested shallow water equation model case.

A Regional Spectral Nested Shallow Water Equation Model

A method to expand meteorological elements in terms of finite double Fourier series in a limited-region and a spectral nested shallow water equation model based upon the method with conformal map projection in rectangular coordinates, have been proposed, and computational stability and efficiency of time integration have been discussed.

Interval Analytic Method in Existence Result for Hyperbolic Partial Differential Equation

Without the usual assumption of monotonicity, we establish some results on the theory of hyperbolic differential inequalities which enable us to produce a majorising interval function for the solution of the hyperbolic initial value problem. Using this function, a variation of parameters formula and interval iterative technique, the existence of solution to the problem is established.

Attribute Reduction in Interval and Set-Valued Decision Information Systems

In many practical situation, some of the attribute values for an object may be interval and set-valued. This paper introduces the interval and set-valued information systems and decision systems. According to the semantic relation of attribute values, interval and set-valued information systems can be classified into two categories: disjunctive (Type 1) and conjunctive (Type 2) systems. In this paper, we mainly focus on semantic interpretation of Type 1. Then, we define a new fuzzy preference relation and construct a fuzzy rough set model for interval and set-valued information systems. Moreover, based on the new fuzzy preference relation, the concepts of the significance measure of condition attributes and the relative significance measure of condition attributes are given in interval and set-valued decision information systems by the introduction of fuzzy positive region and the dependency degree. And on this basis, a heuristic algorithm for calculating fuzzy positive region reduction in interval and set-valued decision information systems is given. Finally, we give an illustrative example to substantiate the theoretical arguments. The results will help us to gain much more insights into the meaning of fuzzy rough set theory. Furthermore, it has provided a new perspective to study the attribute reduction problem in decision systems.

Optimization of Uncertain Structures with Interval Parameters Considering Objective and Feasibility Robustness

For the purpose of improving the mechanical performance indices of uncertain structures with interval parameters and ensure their robustness when fluctuating under interval parameters, a constrained interval robust optimization model is constructed with both the center and halfwidth of the most important mechanical performance index described as objective functions and the other requirements on the mechanical performance indices described as constraint functions. To locate the optimal solution of objective and feasibility robustness, a new concept of interval violation vector and its calculation formulae corresponding to different constraint functions are proposed. The math?ematical formulae for calculating the feasibility and objective robustness indices and the robustness?based preferential guidelines are proposed for directly ranking various design vectors, which is realized by an algorithm integrating Kriging and nested genetic algorithm. The validity of the proposed method and its superiority to present interval optimization approaches are demonstrated by a numerical example. The robust optimization of the upper beam in a high?speed press with interval material properties demonstrated the applicability and effectiveness of the proposed method in engineering.

INTERVAL PARAMETER PERTURBATION METHOD FOR EVALUATING THE BOUNDS ON NATURAL FREQUENCIES OF STRUCTURES WITH INTERVAL PARAMETERS

For structural parameters with uncertainties, interval mathematicscan , in the case where the probabilistic distribution density ofuncertain variables is unavailable, deal with the influ- ence ofuncertainties in structural parameters on the response of structures.In order to evaluate the re- gion containing natural frequencies ofstructures with interval parameters, the interval parameter per-turbation method is presented in this paper. The advantage of thepresent method is its computational efficiency in evaluating theregion containing natural frequencies. A numerical example is used toil- lustrate the efficiency of the method proposed.

A Regional Air-Sea Coupled Model and Its Application over East Asia in the Summer of 2000

A regional air-sea coupled model, comprising the Regional Integrated Environment Model System （RIEMS） and the Princeton Ocean Model （POM） was developed to simulate summer climate features over East Asia in 2000. The sensitivity of the model＇s behavior to the coupling time interval （CTI）, the causes of the sea surface temperature （SST） biases, and the role of air-sea interaction in the simulation of precipitation over China are investigated. Results show that the coupled model can basically produce the spatial pattern of SST, precipitation, and surface air temperature （SAT） with five different CTIs respectively. Also, using a CTI of 3, 6 or 12 hours tended to produce more successful simulations than if using 1 and 24 hours. Further analysis indicates that both a higher and lower coupling frequency result in larger model biases in air-sea heat flux exchanges, which might be responsible for the sensitivity of the coupled model＇s behavior to the CTI. Sensitivity experiments indicate that SST biases between the coupled and uncoupled POM occurring over the China coastal waters were due to the mismatch of the surface heat fluxes produced by the RIEMS with those required by the POM. In the coupled run, the air-sea feedbacks reduced the biases in surface heat fluxes, compared with the uncoupled RIEMS, consequently resulted in changes in thermal contrast over land and sea and led to a precipitation increase over South China and a decrease over North China. These results agree well observations in the summer of 2000.

Identifying camellia oil adulteration with selected vegetable oils by characteristic near-infrared spectral regions

In this paper,a methodology based on characteristic spectral bands of near infrared spectroscopy(1000-2500 nm)and multivariate analysis was proposed to identify camellia oil adulteration withvegetable oils,Sunflower,peanut and corn oils were selected to conduct the test.Pure camlia oiland that adulterated with varying concentrations(1-10%with the gradient of 1%,10-40%withthe gradient of 5%,40-100%with the gradient of 10%)of each type of the three vegetable oilswere prepared,respectively.For each type of adulterated oil,full-spectrum partial least squarespartial least squares(PLS)models and synergy interval partial least squares(SI-PLS)modelswere developed.Parameters of these models were optimized simultaneously by cross-validation,The SI-PLS models were proved to be better than the full-spectrum PLS models.In SI-PLSmodels,the correlation coefficients of predition set(Rp)were 0.9992,0.9998 and 0.9999 foradulteration with sunflower oil,peanut oiloil seperately;the corresponding root meansquare errors of prediction set(RMSEP).66nd 0.37.Furthermore,a new genericPLS model was built based on the chalselected from the intervals of thethree SI-PLS models to identify the oil adulterantsardless of the adultrated oil types.Themodel achieved with Rp=0.9988 and RMSEP==1.52,These results indicated that the charac-teristic near infrared spectral regions could determine the level of adulteration in the camllia oil.

Study on Integrated Recurrence Behaviors of Strong Earthquakes Along Entire Active Fault Zones in the Sichuan-Yunnan Region, China

Based on historical earthquake data, we use statistical methods to study integrated recurrence behaviors of strong earthquakes along 7 selected active fault zones in the Sichuan-Yunnan region. The results show that recurrences of strong earthquakes in the 7 fault zones display near-random, random and clustering behaviors. The recurrence processes are never quasi-periodic, and are neither strength-time nor time-strength dependent. The more independent segments for strong earthquake rupturing a fault zone has, the more complicated the corresponding recurrence process is. And relatively active periods and quiescent periods for earthquake activity occur alternatively. Within the active periods, the distribution of recurrence time intervals between earthquakes has relatively large discretion, and can be modelled well by a Weibull distribution. The time distribution of the quiescent periods has relatively small discretion, and can be approximately described by some distributions as the normal. Both the durations of the active periods and the numbers of strong earthquakes within the active periods vary obviously cycle by cycle, leading to the relatively active periods having never repeated quasi-periodically. Therefore, the probabilistic assessment for middle- and long-term seismic hazard for entireties of active fault zones based on data of historical strong earthquakes on the fault zones still faces difficulty.

面向多区域防洪的珠江流域水库群协同调度模型研究

珠江流域洪水组成与遭遇复杂多变,防洪保护对象多而分散,且兼顾供水、生态、发电、航运、库区安全等多种任务,水库群防洪调度面临多区域、多目标协同调度技术难题。以位于西江、北江、东江上的水库为研究对象,基于流域防洪格局和防洪任务阐明了水库群多区域协同防洪的调度节点和角色定位,提出了嵌套式多维属性的模型功能结构,构建了珠江流域水库群多区域协同防洪调度模型。以流域防洪极为不利的2005年6月中下游型大洪水为例进行流域水库群防洪调度模型研究,结果表明,通过龙滩水库加大拦蓄,岩滩水库、百色水库、西津水库、飞来峡水库等西江、北江水库群协同调度,可将西江梧州站洪峰流量削减至安全泄量50 400 m^(3)/s以下,较原设计调度方案多削减3 200 m^(3)/s,将三角洲思贤滘(马口+三水)断面洪峰削减至62 700 m^(3)/s,较原设计调度方案多削减4 500 m^(3)/s,有效保障了粤港澳大湾区城市的防洪安全。

基于径流模数的LSTM模型在无资料嵌套流域的应用

针对LSTM模型参数在无资料嵌套流域移植效果不佳的问题,以屯溪流域为研究对象,以其嵌套子流域为参证流域,综合考虑面积因素对参数移植法的影响,建立了基于径流模数的LSTM模型(RM-LSTM模型),并采用参数移植法进行流域洪水过程模拟。结果表明:RM-LSTM模型在研究流域应用效果较好,模拟结果的确定性系数达0.87,洪峰、洪量及峰现时间合格率均在85.0%以上;在参证子流域内,RM-LSTM模型参数移植后模拟结果的确定性系数及洪峰、洪量、峰现时间合格率较LSTM模型参数移植结果均有明显提升;RM-LSTM模型能够更好地考虑流域面积变化对参数移植方法的影响。

区域农业全产业链情报生态系统:内涵、结构、特征及运行机制

区域农业全产业链情报生态系统为区域农业全产业链的有效运转提供农资供应、农技服务、生产全过程监测与保障、农产品市场行情、农产品产销对接等情报服务,是区域农业全产业链生态系统的一个重要的功能子系统。在文献梳理的基础上,对区域农业全产业链情报生态系统的内涵作了界定,分析了由微观系统、中间系统、外层系统、宏观系统等4个子系统构成的区域农业全产业链情报生态系统的嵌套结构,提出了区域农业全产业链情报生态系统是一个具有开放性、区域性、复杂性、共生性与协同演化性等多方面特征的情报生态协同体,并结合安徽皖垦集团案例作了深入分析。最后,解析了区域农业全产业链情报生态系统的全产业链各节点间的协同驱动、外层系统与中间系统间的协同驱动、情报聚合与输送、多维立体驱动和动态演化驱动等五大关键运行机制。

考虑工作点时变特性的并网变流器全工作区间稳定性分析

现有工程运行数据显示,并网变流器(grid-connected converter,GCC)的动态特性与工作点密切相关。受新能源出力波动、负载投切等外部因素的影响,变流器工作点呈现随机时变特性。因此,分析整个工作区间中所有工作点的系统稳定性具有重要意义。传统阻抗/导纳分析方法可以有效分析GCC运行于特定工作点时的稳定性,但考虑系统所有可能工作点时则需重复分析,工作量大且难度较高。为解决这一难题,提出一种考虑工作点变量的多元建模方法。将工作点变量引入导纳模型,通过控制环路重构,建立GCC的多变量单输入单输出(single input single output,SISO)模型。所提模型直接包含工作点变量,因此可以有效分析变流器全工作区间动态特性。此外,综合考虑变流器最大传输限制和动态特性,提出一种基于安全运行域的稳定性分析方法,以实现多维工作区间中系统稳定性的直观表征。仿真和实验验证了所提多变量SISO模型和基于安全运行域的分析方法的正确性。所提模型和方法在分析电力电子装置运行极限、指导变流器设计和辅助功率器件发挥极限性能等工程场景中具有广泛应用潜力。

计划烧除对滇中云南松林土壤养分的影响

【目的】探究计划烧除及其时间间隔对云南松Pinus yunnanensis林土壤碳氮磷钾化学计量特征的影响。【方法】以滇中地区玉溪市新平彝族傣族自治县照壁山云南松林为研究对象,分别在未烧除样地(对照)、连续每年实施计划烧除后间隔1 a样地(T1)和间隔3 a样地(T2),分层采集0~10和10~20 cm土层土壤,测定土壤碳、氮、磷、钾4种养分元素质量分数,采用方差分析、Spearman相关分析和主成分分析(PCA)探究计划烧除后不同间隔时间对滇中云南松林土壤化学计量特征的影响。【结果】与对照样地相比,T1样地的2个土层土壤pH均无显著变化,T2样地的2个土层土壤pH均极显著增加(P<0.01);T1和T2样地2个土层的土壤总碳、有机碳、总氮、碱解氮质量分数均无显著差异,T2样地的0~10 cm土层土壤有效磷质量分数显著降低(P<0.05),2个土层的土壤速效钾质量分数均显著增加(P<0.05),土壤碳氮比仅在T2样地10~20 cm土层显著增加(P<0.05)。【结论】计划烧除对研究区土壤养分质量分数的影响受烧除间隔时间和土层深度等因素的共同影响,2种烧除后间隔时间均对研究区云南松林土壤碳氮质量分数无显著影响,但对土壤pH、碳氮比、有效磷和速效钾有显著影响。

区间值决策系统的多特定类属性约简

多特定类的属性约简是粗糙集理论研究的重要分支。通常用户在决策时只关注部分决策类,而现有算法是关注全部决策类,针对部分决策类的约简效率不高。为此,本文提出多特定类的快速约简模型。该模型充分利用正域、边界域和负域的特点,提出了关于多特定类的属性约简算法。实验结果表明,本文提出的算法效率较高,约简长度相对较短。

做平面运动滚子从动件盘形凸轮机构第Ⅱ类综合问题的广义化研究

提出了"狭义、广义第Ⅱ类机构综合问题"的概念;通过建立预备公式、引入"旋浮数轴"概念等,对于一维情形,提出"瞬时/整程区间套"的求解原理和区间套存在性(态)的判定方法,并求解其"劣解/非劣解区间套"和"区间最优解";对于二维情形,提出"有解区间套"、"整程区域套/机构解全域"的求解原理和区域套存在性(态)的判定方法,并求解其"劣解/非劣解区域套"和"全域最优解"等;基于Visual Basic6.0软件开发了具有可视化、规律发掘功能的通用软件CALRFCY,从而解决了"广义第Ⅱ类机构综合"解的存在性(态)判定及其求解方法的问题。通过两个机构综合实例论证了偏置式机构较正置式机构具有"你无我有,你有我优"的固有潜质和显著优越性。

作平面运动滚子从动件盘形凸轮机构的第Ⅱ类机构综合问题

将作平面运动滚子从动件盘形凸轮机构的尺寸综合概括为Ⅰ、Ⅱ两大类的机构综合问题,并归纳概括出两大类机构综合问题的准确描述。关于第Ⅰ类的机构综合问题,通过引入'虚拟摆杆'的概念,在理论上很早即已得到理想解决。针对第Ⅱ类的机构综合问题,选取具有代表性的德国进口高速印刷机机构为例,研究提出其分析综合的普适性思路、方法和步骤。通过坐标系建立、'浮动数轴'概念引入、推程前半和后半区段划分,特别是通过首次提出'瞬时区间套'、'整程区间套'等若干新概念,推导得到求解'瞬时、整程区间套'的一整套通用解析公式,给出机构解的存在性和存在特征的解析判据,进而提出滚子中心容许选择区段、凸轮基圆半径许用取值范围的确定方法。给出机构综合的一个算例。

区间值模糊集合的表现定理

针对区间值模糊集合 ,给出了 2类区间值集合套的定义 ,得到了 2个区间值模糊集合的表现定理 .

浮动推杆盘形凸轮机构广义第Ⅱ类机构综合问题

通过坐标系建立、浮动数轴概念提出和推程前半/后半区段划分,特别是通过引入偏距,在预定连杆方位线——一维综合前提框架下,关于偏置式机构,提出整程区间套存在性(态)内涵及求解原理,滚子中心、凸轮理论基圆半径的存在性(态),非劣解、劣解区间套和区间最优解等的求解理论方法。随之,对偏距解得其有解区间套,在非预定连杆方位线——二维综合前提框架下,关于偏置/正置式机构,提出整程区域套——机构解全域、非劣解、劣解区域套和全域最优解等新概念及其求解理论方法。在已有正置式机构第Ⅱ类综合问题研究成果基础上,研究解决了偏置式机构的一维和偏置/正置式机构的二维第Ⅱ类综合问题。拓展丰富了机构综合问题的解空间和优解空间,阐释论证了引入偏置式机构并开展研究具有重要的理论价值和实际意义。通过两个机构综合实例,论证了偏置式较正置式机构的优越性。