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1.
元素判别值分配法在用于求解运筹学一般运输调配与货郎担问题时,鉴于两类问题求解的不同,故使用的算法与调用的程序也不同.现已研制成功综合的求解算法与求解程序。则调用综合算法的程序.它既可求解一般运筹学的调配问题,也可求解货郎担问题;既可求最小值的问题,也可用于求解目标函数为最大值的问题.由于它只需一次调用,便可求解所属问题的最优解,是目前最有效的求解新方法.  相似文献   

2.
考虑给定下降时间函数的降线问题的求解,将降线问题转化为阿贝尔积分方程求解问题.对于无限区间上的积分方程,介绍了阿贝尔运用拉普拉斯变换求解积分方程的过程,给出了求解公式;对于有限区间上的积分方程,采用阿贝尔积分变换法进行求解,运用累次积分交换积分次序,由一个定积分的恒等式得出求解公式,并将积分方程的求解公式应用于等时降线问题的求解,通过求解等时降线问题的微分方程,证明了等时降线是一条倒摆线.  相似文献   

3.
归纳总结浮力问题的求解方法为:一“读数差示解法;二、压力差求解法;三、公式型求解法;四、悬体型求解法;五、综合型求解法。  相似文献   

4.
针对汽车转向非线性平衡点求解问题,研究了遗传算法求解效果并提出改进方法.建立汽车转向二自由度模型,说明汽车转向非线性平衡点只能数值迭代求解的原因,构造适于智能优化方法的适应度函数,提出了确定可行求解范围的方法.在车速70 km/h、路面附着系数0.5和前轮转角0~0.2 rad的行驶条件下,应用遗传算法求解得到3个平衡点.通过比较大小两个转角的适应值曲面,说明遗传算法求解小转角平衡点不满足精度的原因,提出了遗传算法与BFGS(broyden-fletcher-goldfarb-shanno)拟牛顿法融合的求解流程.结果表明:融合求解流程可以求解满足精度要求的小转角平衡点,求解效率高于遗传算法,弥补了遗传算法单独求解的不足.  相似文献   

5.
目前求解事故树结构重要度主要有三种求解法。针对三种方法求解时会出现结果不一致的现象,以一个小型事故树实例,分别采用三种求解法进行求解计算,寻求其各自的特点和适用环境。当事故树中基本事件数目较多时,采用最小割(径)集法求解;当需要得到精确计算结果时,采用结构重要度系数法求解;当采用最小割集(最小径集)法求解结构重要度排序存在不一致时,可采用结构重要度系数法或概率重要度性质法求解。行车起重设备吊物坠落事故实例,验证了事故树结构重要度求解方法的有效性。该研究为恰当的选择和使用结构重要度求解法提供了参考。  相似文献   

6.
总结了硕士研究生入学数学统考试题中有关线性方程组的题型,主要有不合参数的线性方程组求解、含参数的线性方程组求解、线性方程组公共解的求解和矩阵秩求解四种类型.并且归纳出四种题型相应的求解方法.  相似文献   

7.
一种提高现有有限元求解器速度的方法   总被引:1,自引:1,他引:1  
静力方程求解器是有限元分析程序的核心。随着求解规模的增大 ,求解器往往成为其工作的瓶颈。目前大量有限元程序采用的是一维变列高存储格式的直接法求解器 ,在这种求解器中引入循环展开 (loop- unrolling)技术以改进其工作性能。算例表明 ,求解速度得到很大提高。  相似文献   

8.
函数极限的求解是高等数学这门课程中的一个重要知识点,根据题目的难易程度将limx→x0f(x)型函数极限的求解分成五种类型:①利用函数的连续性求解;②利用恒等变形求解;③利用两个重要极限及无穷小量的知识求解;④利用L' Hospital法则求解;⑤综合运用.  相似文献   

9.
从图像运动估计中的基本假设——灰度不变假设出发,用优化方法建立了基于整幅图像匹配的数字散斑相关方法(也称为数字图像相关方法)求解模型,即全场优化求解模型.从建立的全场求解模型出发可引申出常用的两类数字散斑相关方法的求解思路,即基于离散的子区匹配的数字散斑相关方法求解模型和基于有限元的数字散斑相关方法求解模型.从模型建立及求解分析中可知,位移表征模式是数字散斑相关方法求解模型的关键,不同的位移表征模式可构成不同的数字散斑相关方法求解方法.  相似文献   

10.
在符号执行中,约束求解主要负责路径可达性进行判定及测试输入生成的工作,但路径爆炸问题带来的频繁调用,以及SMT求解器本身的能力和效率的不足,使得约束求解占用了符号执行中主要的性能开销,约束求解问题也成为符号执行中面临的主要瓶颈问题之一.本文介绍了符号执行和约束求解的基本概念,并分析了符号执行中约束求解问题的由来,对近年来的约束求解问题研究进展进行了归类,涉及的技术包括非相关约束分支切片、约束简化、快速不满足性检查及多求解器支持等.对这方面的研究进行了展望和总结.提出未来工作应在提高路径约束逻辑精简率、提高约束求解结果存储和重用的效率、约束求解并行化以及约束求解配置预测等方面展开.   相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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