Efficient Algorithms for Determining 3-D Bi-Plane Imaging Geometry

Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the 3-D structure can be accurately reconstructed. Based on interesting observations and efficient geometric techniques, we present in this paper new algorithmic solutions for this problem. Comparing with existing optimization-based approaches, our techniques yield better accuracy and have bounded execution time, thus is more suitable for on-line applications. Our techniques can easily detect outliers to further improve the accuracy.This research was supported in part by NIH under USPHS grant numbers HL52567.     

MATLAB在工程图学中的应用

计算机技术的发展为工程图学注入了新的活力。从引入计算机辅助设计理念到融合数学与计算机图形学技术,都影响着工程图学课程的内容和教学方式。本文分析了传统图学投影理论中所包含的数学信息,增强了"图"与"数"的内在联系,为传统图学理论更加实用发掘新的契合点。     

冷库大门的空气幕结构设计计算模型

通过对冷库大门处的流场分析,用理论的方法建立流场。根据流线流量原理,导出冷库大门空气幕结构设计计算的数学模型。     

Column generation with free replicability in DEA

The evaluation of efficiency scores in data envelopment analysis is based on the construction of artificial decision making units subject to some assumptions, usually requiring convexity of the production possibility set. This demands divisibility in input and output, which is not always possible. The so-called free replicability model, proposed by Henry Tulkens, permits input and output to enter in only discrete amounts. The model is of a mixed integer programming type, for which the number of variables, here corresponding to the decision making units, may be critical in order to reach an optimal solution.     

Lattice path counting and the theory of queues

In this paper we will show how recent advances in the combinatorics of lattice paths can be applied to solve interesting and nontrivial problems in the theory of queues. The problems we discuss range from classical ones like M^a/M^b/1$M^a/M^b/1$ systems to open tandem systems with and without global blocking and to queueing models that are related to random walks in a quarter plane like the Flatto–Hahn model or systems with preemptive priorities.     

裂缝天线缝制造精度对电性能影响的预测

为了避免传统方法在分析结构因素对电性能影响时需要假设和近似处理的弊端,提出了根据平板裂缝天线生产制造中的数据,使用支持向量回归建立缝制造精度对电性能指标影响的预测方法。给出了一种以最小化支持向量回归的拟合能力和泛化能力为目标函数来选择支持向量回归机参数的方法,以方便该方法的工程应用。案例研究表明,该方法能够较准确地预测缝制造精度对电性能的影响;与传统的BP神经网络和最小二乘法对比,该方法具有更好的泛化能力,可以应用到平板裂缝天线的计算机辅助制造中。     

高层建筑型体设计探讨

分析了高层建筑型体演变、长宽、高厚比尺度、平面构成、立面型体及设计要点、方法。     

平面铰链四杆机构具有曲柄的条件推导及讨论

以非常直观的方法 ,分别就两连架杆作整周运动的情况 ,推导了平面铰链四杆机构具有单曲柄与双曲柄的条件 ,并对其特例在天平、升降机方面的应用进行了讨论。     

二次曲面的公共自极四面体

本文主要在射影空间中,研究二次曲面的公共自极四面体的存在性与唯一性问题,当存在时,给出求它的顶点坐标的一般方法.     

平面广告图形图像符号语义表述探究

随着商品经济文化的发展,平面广告图形图像符号语义的功能性、技术性、艺术性得到设计师的高度重视,符号语义表达呈现复杂而系统的特性。创作、符号、审美三个环节共生共容,符号语义既呈现其独立性,又遵循设计语境和受众阅读能力及思维惯式,文章对图形图像符号语义的联想表述、象征表述、衬托表述和隐寓表述进行了分析和论述。