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三维机加工工艺工序间模型快速创建方法 被引量:18
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作者 刘金锋 倪中华 +2 位作者 刘晓军 程亚龙 尹强 《计算机集成制造系统》 EI CSCD 北大核心 2014年第7期1546-1552,共7页
为达到机加工零件快速工艺设计的目的,对快速创建工序间模型的方法进行了研究。根据机加工零件模型加工特征的生成方式及特点,将加工特征分为凹陷特征、凸起特征和过渡特征;以特征识别技术为基础、特征面组为研究对象,结合工艺知识识别... 为达到机加工零件快速工艺设计的目的,对快速创建工序间模型的方法进行了研究。根据机加工零件模型加工特征的生成方式及特点,将加工特征分为凹陷特征、凸起特征和过渡特征;以特征识别技术为基础、特征面组为研究对象,结合工艺知识识别出所需加工特征的面组;运用半空间思想及基本建模方法,获取制造特征体并保存;获取所有制造特征体后生成零件毛坯模型,与获取的制造特征体进行布尔操作,快速创建工序间模型。以某机加工零件为例,对该算法进行了实例验证。 展开更多
关键词 工序间模型 特征识别 制造特征体 加工特征
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基于工艺模型的工艺信息表达与管理技术 被引量:11
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作者 刘金锋 倪中华 +1 位作者 刘晓军 程亚龙 《计算机集成制造系统》 EI CSCD 北大核心 2015年第7期1756-1763,共8页
针对机加工三维工艺规划系统对工艺信息进行有效表达和管理的需求,提出以工序间模型为载体实现简便有效表达和管理工艺信息的方法。分析了零件加工过程中的工艺信息,并将其分为静态工艺信息和动态工艺信息;定义了三维工序间模型并确定... 针对机加工三维工艺规划系统对工艺信息进行有效表达和管理的需求,提出以工序间模型为载体实现简便有效表达和管理工艺信息的方法。分析了零件加工过程中的工艺信息,并将其分为静态工艺信息和动态工艺信息;定义了三维工序间模型并确定工艺信息在该模型上的表达方案;利用工艺信息的结构层次关系实现对工艺信息的有效管理,构建了工艺管理器对工艺信息进行组织与存储;将所提工艺信息表达与管理技术集成到三维工艺规划系统中,并以创建零件加工过程中的三维工艺模型为例,验证了所提工艺信息表达与管理技术的有效性。 展开更多
关键词 工序间模型 工艺模型 工艺信息 三维工艺规划
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Rainfall Forecasting Using Fourier Series
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作者 Nasser Rostam Afshar Hedayat Fahmi 《Journal of Civil Engineering and Architecture》 2012年第9期1258-1262,共5页
The need for accurate rainfall prediction is readily apparent when considering many benefits in which such information would provide for river control, reservoir operation, forestry interests, flood mitigation, etc.. ... The need for accurate rainfall prediction is readily apparent when considering many benefits in which such information would provide for river control, reservoir operation, forestry interests, flood mitigation, etc.. Due to importance of rainfall in many aspects, studies on rainfall forecast have been conducted since a few decades ago. Although many methods have been introduced, all the researches describe the study as complex because it involves numerous variables and still need to be improved. Nowadays, there are various traditional techniques and mathematical models available, yet, there are no result on which method provide the most reliable estimation. AR (auto-regressive), ARMA (auto-regressive moving average), ARIMA (auto-regressive integrated moving average) and ANNs (artificial neural networks) were introduced as a useful and efficient tool for modeling and forecasting. The conventional time series provide reasonable accuracy but suffer from the assumptions of stationary and linearity. The concept of neurons was introduced first which then developed to ANNs with back propagation training algorithm. Although certain ANNs) models are equivalent to time series model, but it is limited to short term forecasting. This Paper presents a mathematical approach for rainfall forecasting for Iran on monthly basic. The model is trained for monthly rainfall forecasting and tested to evaluate the performance of the model. The result Shows reasonably good accuracy for monthly rainfall forecasting. 展开更多
关键词 RAINFALL forecasting Fourier series MAXIMUM 1 st year mean and minimum rainfall.
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Layout Design-Based Research on Optimization and Assessment Method for Shipbuilding Workshop
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作者 Yang Liu Mei Meng Shuang Liu 《Journal of Marine Science and Application》 2013年第2期152-162,共11页
The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding worksh... The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding workshop. By utilizing a steel processing workshop as an example, the principle of minimum logistic costs will be implemented to obtain an ideological equipment layout, and a mathematical model. The objectiveness is to minimize the total necessary distance traveled between machines. An improved control operator is implemented to improve the iterative efficiency of the genetic algorithm, and yield relevant parameters. The Computer Aided Tri-Dimensional Interface Application (CATIA) software is applied to establish the manufacturing resource base and parametric model of the steel processing workshop. Based on the results of optimized planar logistics, a visual parametric model of the steel processing workshop is constructed, and qualitative and quantitative adjustments then are applied to the model. The method for evaluating the results of the layout is subsequently established through the utilization of AHP. In order to provide a mode of reference to the optimization and layout of the digitalized production workshop, the optimized discrete production workshop will possess a certain level of practical significance. 展开更多
关键词 visual parametric model steel processing workshop layout optimization design improved genetic algorithm assessment methods optimization algorithm shipbuilding workshop
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Is China’s Economic Growth Profitled or Wage-led?——A Theoretical Inquiry and Empirical Study on the Impact of Labor Share on Growth
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作者 刘盾 施祖麟 林玳玳 《China Economist》 2015年第3期83-99,共17页
The paper makes a comparative review and evaluation of different theories on impacts of the distribution of labor and capital income on economic growth as well as criticism of the mainstream theories and suggests usin... The paper makes a comparative review and evaluation of different theories on impacts of the distribution of labor and capital income on economic growth as well as criticism of the mainstream theories and suggests using Bhaduri-Marglin model as the theoretical basis for relevant research. By formulating the econometric model and analyzing time series data from 1978 to 2012, the paper makes an empirical research into the impact of labor share on economic growth in China. It has discovered that the positive effect of labor share on consumption demand growth in China outweighs its negative effect on investment and net export growth, concluding that growth in China is wage-led at present. That may mean that (1) increasing labor share promotes growth and the goals of equality and efficiency supports each other," (2) the demand and optimizing structure" lies in regulation tools. key to "stabilizing growth, expanding domestic establishing a set of pro-labor institution and 展开更多
关键词 labor share labor-capital distribution factors income distribution economicgrowth wage-led growth effective demand
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