基于多域集成设计的飞机装配资源模型

为了有效分类装配资源,为资源库的开发提供服务,提升装配仿真效果,提出以装配作业、仿真过程、资源属性等要素为分类依据的资源分类方法,基于图组方法建立了资源定义分类模型与信息集成模型,描述了资源的属性,并以BNF范式进行了表述。设计了多域集成模型,系统研究了飞机装配资源的种类和属性,同时给出映射过程。最终提出了某类小型飞机的装配资源模型,验证了该方法的有效性。

面向设计状态递进转换的零件多域视图模型

在零件自顶向下的设计过程中,随着领域知识的不断引入,其设计状态不断递进转换。为构建零件从功能到结构规范化的演化过程,分析了零件功能和结构约束的映射关系,完整表达了零件设计状态的转换过程,定义了从功能到结构语义、零件约简结构至详细结构的渐进式的零件多域视图模型。通过对零件模型的功能约束、拓扑结构及作用关系的分析,以及对零件构成单元的功能时序、功能单元、几何结构、形位、装配与进化序列的分析,建立了基于功能约束和结构约束的零件关联约束模型,并将抽象语义知识进行结构化处理,构建了由功能视图模型、功能结构过渡语义描述模型、结构约简视图模型和结构视图模型组成的自顶向下的、渐进式零件多域视图模型。根据零件特征信息的表达层次和表达需求对上述各视图模型进行表述,体现零件在不同形态、不同阶段的设计知识,形成一个具有过程性、动态性、层次性和递进演化特性的零件对象定义模型。基于多域视图模型,可形成零件结构的多重解释,从而实现功能驱动的零件结构系列化设计,拓展狭义的零件结构设计的范畴,有助于实现基于模型的计算机辅助零件设计,推进产品设计过程的自动化和智能化。

基于结构分析的断路器操作机构的建模及仿真分析

基于断路器的结构来建模有利于研究断路器每个元件对其分合闸过程特性的不同影响,这对实现故障部位识别,进行故障分类及诊断都具有重要意义。文中针对断路器各个部分的功能特性分别建立机械与电气模型。然后利用机械与电气之间的相互联系,通过MATLAB/Simulink软件将单个部分模型组合来形成高压断路器的多域模型。随后设定所研究的高压断路器参数,在MATLAB/Simulink环境中进行仿真获取断路器的分闸行程曲线及分闸线圈电流特性,再通过改变模型中机械部分的摩擦参数及弹簧刚度系数得到不同的位移特性以及改变电气部分的参数获取不同的线圈电流特性。最后将所得结果进行分析,得出不同参数对断路器部分特性的影响,为未来更好、更全面地进行故障分类及诊断奠定一定的基础。

船舶运动模拟器ADRC控制系统的设计与仿真

针对并联式船舶运动模拟器具有多变量,强耦合,结构复杂,难以获得精确的数学模型等特点,给出了一种ADRC控制器设计及实现方案.使用参数化设计方法,在Simulink中构建了机械、液压、控制一体化多域仿真模型,分析了控制器的参数整定方法,仿真结果表明了仿真模型和ADRC控制器的有效性.

A novel algorithm for establishing taxonomic relation of Chinese ontology

Both a general domain-independent bottom-up multi-level model and an algorithm for establishing the taxonomic relation of Chinese ontology are proposed.The model consists of extracting domain vocabularies and establishing taxonomic relation,with the consideration of characteristics unique to Chinese natural language.By establishing the semantic forests of domain vocabularies and then using the existing semantic dictionary or machine-readable dictionary(MRD),the proposed algorithm can integrate these semantic forests together to establish the taxonomic relation.Experimental results show that the proposed algorithm is feasible and effective in establishing the integrated taxonomic relation among domain vocabularies and concepts.

The Common Principal Component Analyses of Multi-RCMs

Based on a 10-year simulation of six Regional Climate Models(RCMs) in phase II of the Regional Climate Model Inter-Comparison Project(RMIP) for Asia,the multivariate statistical method of common principal components(CPCs) is used to analyze and compare the spatiotemporal characteristics of temperature and precipitation simulated by multi-RCMs over China,including the mean climate states and their seasonal transition,the spatial distribution of interannual variability,and the interannual variation.CPC is an effective statistical tool for analyzing the results of different models.Compared with traditional statistical methods,CPC analyses provide a more complete statistical picture for observation and simulation results.The results of CPC analyses show that the climatological means and the characteristics of seasonal transition over China can be accurately simulated by RCMs.However,large biases exist in the interannual variation in certain years or for individual models.

A Community and Ecosystem-based Sustainable Forest Management Model for Small Islands in Maluku

The research objective was to investigate past and current forest management practices in the Maluku archipelago, then to create a better management model to improve prosperity for local communities and to guarantee sustainability of forest ecosystems for future generations. Forest land use, the deforestation process, the potential for maintaining natural production forests and the need to establish a management unit for sustainability of natural production forests （PFMU） were analysed. The analysis model used Geographic Information System （GIS） and satellite imaging. The deforestation process was analysed using the multiple regression model. The research determined the importance of two concepts i.e., （1） A macro concept involving the integration of forest development with regional development and （2） A micro concept which detailed the format of the PFMU as a sub-set of the macro concept. The macro concept involves a new Forest Land Use Plan （FLUP）, and the micro concept is a more detailed analysis of a sustainable PFMU, a Management Unit for Protection Forest （PrFMU） and a Management Unit for Conservation Forest （CFMU）. Results showed that the existing FLUCP （Forest Land Use Consensus Plan） policy rather than guaranteeing the sustainability of forests, contributed to their deforestation. The integration of forest management and regional development strategies required the establishment of a new FLUP.

Updating Methods for Real Time Flood Forecasting： A Comparison through Senegal River Basin Upstream Bakel

Heavy floods occur frequently in the Senegal River Basin, causing catastrophic flooding downstream the river rating station of Bakel. Anticipating the occurrence of such phenomena is the only way to reduce the resulting damages. Flood forecasting is a necessity. Flood forecasting plays also an important role in the implementation of flood management scenarios and in the protection of hydro electric structures. Many methods are applied. The most complete are based on the conservation laws of physics governing the free surface flow. These methods need a complete description of the geometry of the river and their implementation requires also huge investments. In practice the river basin can be considered as a system of inputs-outputs related by a transfer function. In this paper the authors first used a multiple linear regression model with constant parameters estimated by the ordinary least square method to simulate the propagation of the floods in the upstream part of the Senegal river basin. The authors then apply statistical and graphical criteria of goodness-of-fit to test the suitability of this model. Three procedures of parameters updating have then been added to this linear model： the Kalman filter method, the recursive least square method, and the stochastic gradient method The criteria of goodness-of-fit used above have shown that the stochastic gradient method, although more rudimentary, represents better the flood propagation in the head basin of the Senegal river upstream Bakel. This result is particularly interesting because data influenced by Manantali Dam are used.

A modified simulated annealing algorithm and an excessive area model for floorplanning using fixed-outline constraints

Outline-free floorplanning focuses on area and wirelength reductions, which are usually meaningless, since they can hardly satisfy modern design requirements. We concentrate on a more difficult and useful issue, fixed-outline floorplanning. This issue imposes fixed-outline constraints on the outline-free floorplanning, making the physical design more interesting and challenging. The contributions of this paper are primarily twofold. First, a modified simulated annealing(MSA) algorithm is proposed. In the beginning of the evolutionary process, a new attenuation formula is used to decrease the temperature slowly, to enhance MSA's global searching capacity. After a period of time, the traditional attenuation formula is employed to decrease the temperature rapidly, to maintain MSA's local searching capacity. Second, an excessive area model is designed to guide MSA to find feasible solutions readily. This can save much time for refining feasible solutions. Additionally, B*-tree representation is known as a very useful method for characterizing floorplanning. Therefore, it is employed to perform a perturbing operation for MSA. Finally, six groups of benchmark instances with different dead spaces and aspect ratios—circuits n10, n30, n50, n100, n200, and n300—are chosen to demonstrate the efficiency of our proposed method on fixed-outline floorplanning. Compared to several existing methods, the proposed method is more efficient in obtaining desirable objective function values associated with the chip area, wirelength, and fixed-outline constraints.

Study of the nose event on 11 April 2002 with UBK method

Nose event,which names after the nose-like shape of structures in ion spectrograms observed by satellite in the inner magnetosphere,refers to the deep inward penetration of ions from magnetotail at discrete energy bands.Nose events have been studied extensively both with observations and simulations since first discovered in 1970s.In this study we use the UBK method to model the different L-shell penetration characteristics for a multi-band nose event observed by Cluster/CODIF on April 11,2002.The modeled open-closed orbit separatrices are generally smaller than the observed L-shell penetrations for outbound crossing;the difference varies from 2.02 to 0.62 R E for different energy channels of H + bands and from 1.88 to 1.10 R E for O + band.The average difference is 1.46 R E.The separatrices for the inbound crossing are generally larger than those of outbound crossing and are more consistent with the observed L-shell penetration depths.The modeled open-closed orbit separatrices are smaller than the observed L-shell penetrations for 6.5-17.1 keV energy channels of H + bands but larger for 4.0-5.1 keV(due to closed banana orbits region) and 21.7-35.2 keV(due to energy increasing) energy channels of H + bands.For O + band,the difference between the modeled open-closed orbit separatrix and observed L-shell penetrations of 4.6 keV energy channel is larger(due to closed banana orbits region),the difference of 7.4 keV energy channel is smaller.The overall average difference is 0.043 R E for nose structures of inbound crossing.The discrepancies between the model and observation may come from the magnetic field and electric potential models we used.The formation of multi nose event and relations to the observed plasma flow vortices are discussed,the local intense E Y may relate to the formation of the observed multi nose structures.

Changes in production potentials of rapeseed in the Yangtze River Basin of China under climate change:A multi-model ensemble approach

Rapeseed is one of the major oil crops in China and it is very sensitive to climate change.The Yangtze River Basin is the main rapeseed production area in China.Therefore,a better understanding of the impact of climate change on rapeseed production in the basin is of both scientific and practical importance to Chinese oil industry and food security.In this study,based on climate data from 5 General Circulation Models(GCMs) with 4 representative concentration pathways(RCPs) in 2011–2040(2020 s),2041–2070(2050 s) and 2071–2100(2080 s),we assessed the changes in rapeseed production potential between the baseline climatology of 1981–2010 and the future climatology of the 2020 s,2050 s,and 2080 s,respectively.The key modelling tool – the AEZ model – was updated and validated based on the observation records of 10 representative sites in the basin.Our simulations revealed that:(1) the uncertainty of the impact of climate change on rapeseed production increases with time;(2) in the middle of this century(2050 s),total rapeseed production would increase significantly;(3) the average production potential increase in the 2050 s for the upper,middle and lower reaches of the Yangtze River Basin is 0.939,1.639 and 0.339 million tons respectively;(4) areas showing most significant increases in production include southern Shaanxi,central and eastern Hubei,northern Hunan,central Anhui and eastern Jiangsu.

Contact stress non-uniformity of wafer surface for multi-zone chemical mechanical polishing process

A finite element analysis(FEA)model is developed for the chemical-mechanical polishing(CMP)process on the basis of a 12-in five-zone polishing head.The proposed FEA model shows that the contact stress non-uniformity is less dependent on the material property of the membrane and the geometry of the retaining ring.The larger the elastic modulus of the pad,the larger contact stress non-uniformity of the wafer.The applied loads on retaining ring and zone of the polishing head significantly affect the contact stress distribution.The stress adjustment ability of a zone depends on its position.In particular,the inner-side zone has a high stress adjustment ability,whereas the outer-side zone has a low stress adjustment ability.The predicted results by the model are shown to be consistent with the experimental data.Analysis results have revealed some insights regarding the performance of the multi-zone CMP.