AN ALGORITHM OF DISTANCE CALCULATION BETWEEN A BOUNDING SPHERE AND A BOUNDING CSG PRIMITIVE

A simple method for calculating distance between a solid sphere and a constructive solid geometry (CSG) so lid primitive (including block, cone, cylinder, sphere, wedge and torus) is derived to support the collision detection algorithm. By decomposing the whole space into relative positions and geometric features of the sphere and the primitive considered, closed form distance formula are got. These calculations are very useful in the real time collision detection in which primitives are used as bounding volumes of complex objects.

Solution-Distance-Based Migration Rate Calculating for Biogeography-Based Optimization

Biogeography-based optimization(BBO),a natureinspired optimization algorithm(NIOA),has exhibited a huge potential in optimization.In BBO,the good solutions have a large probability to share information with poor solutions,while poor solutions have a large probability to accept the information from others.In original BBO,calculating for migration rates is based on solutions' ranking.From the ranking,it can be known that which solution is better and which one is worse.Based on the ranking,the migration rates are calculated to help BBO select good features and poor features.The differences among results can not be reflected,which will result in an improper migration rate calculating.Two new ways are proposed to calculate migration rates,which is helpful for BBO to obtain a suitable assignment of migration rates and furthermore affect algorithms ' performance.The ranking of solutions is no longer integers,but decimals.By employing the strategies,the ranking can not only reflect the orders of solutions,but also can reflect more details about solutions' distances.A set of benchmarks,which include 14 functions,is employed to compare the proposed approaches with other algorithms.The results demonstrate that the proposed approaches are feasible and effective to enhance BBO's performance.

The Method of Calculating Average Skidding Distance

By analyzing the existing average skidding distance formulac and the shape of the landing area, theauthors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and the landing collectioll area is in proportion to of average geometrical skidding distance. The new models of calculating average distance are presented.

基于Levenshtein distance算法的句子相似度计算

基于Levenshtein distance(LD)算法,以计算句子相似度为切入点,通过实验分析对自然语言处理过程中如何计算两个句子的相似度进行研究。实验证明在度量两个句子相似度的计算方法中Levenshtein distance(LD)算法是度量两个句子相似度的有力算法或工具,有助于在拼写检查、雷同试卷分析等程序开发过程中编写出更加高效的代码。

Ranking Method for Complementary Judgment Matrixes with Fuzzy Numbers Based on Hausdorff Metric Distance

A method for ranking complementary judgment matrixes with traspezoidal fuzzy numbers based on Hausdorff metric distance and fuzzy compromise decision approach is proposed. With regard to fuzzy number complementary judgment matrixes given by a decider group whose members have various weights, the expert＇s information was aggregated first by means of simple weight average（SWA） method and Bonissone calculational method. Hence a matrix including all the experts＇ preference information was got. Then the matrix＇ column members were added up and the fuzzy evaluation values of the alternatives were got. Lastly, the Hausdorff metric distance and fuzzy compromise decision approach were used to rank the fuzzy evaluation values and then the ranking values of all the alternatives were got. Because exact numbers and triangular fuzzy numbers could all be transformed into trapezoidal fuzzy numbers, the method developed can rank complementary judgment matrixes with trapezoidal fuzzy numbers, triangular fuzzy numbers and exact numbers as well. An illustrative example is also given to verify the developed method and to demonstrate its feasibility and practicality.

DIMZAL:A Software Tool to Compute Acceptable Safety Distance

The scope of this work is to present a multidisciplinary study in order to propose a tool called DIMZAL. DIMZAL forecasts fuelbreak safety zone sizes. To evaluate a safety zone and to prevent injury, the Acceptable Safety Distance (ASD) between the fire and firefighters is required. This distance is usually set thanks to a general rule-of-thumb: it should be at least 4 times the maximum flame length. A common assumption considers an empirical relationship between fireline intensity and flame length. In the current work which follows on from an oral presentation held at the VII International Conference on Forest Fire Research in Coimbra in 2014, an alternative way is proposed: a closed physical model is applied in order to quantize the ASD. This model is integrated in a software tool, which uses a simulation framework based on Discrete EVent system Specification formalism (DEVS), a 3D physical real-time model of surface fires developed at the University of Corsica and a mobile application based on a Google SDK to display the

Scheme of long distance power supply for electrified railway traction network based on traction cable

Purpose–The traction cable is paralleled with the existing traction network of electrified railway through transverse connecting line to form the scheme of long distance power supply for the traction network.This paper aims to study the scheme composition and power supply distance(PSD)of the scheme.Design/methodology/approach–Based on the structure of parallel traction network(referred to as“cable traction network(CTN)”),the power supply modes(PSMs)are divided into cableþdirect PSM and cableþautotransformer(AT)PSM(including Japanese mode,French mode and new mode).Taking cableþJapanese AT PSM as an example,the scheme of long distance power supply for CTN under the PSMs of co-phase and out-of-phase power supply are designed.On the basis of establishing the equivalent circuit model and the chain circuit model of CTN,taking the train working voltage as the constraint condition,and based on the power flow calculation of multiple train loads,the calculation formula and process for determining the PSD of CTN are given.The impedance and PSD of CTN under the cableþAT PSM are simulated and analyzed,and a certain line is taken as an example to compare the scheme design.Findings–Results show that the equivalent impedance of CTN under the cableþAT PSM is smaller,and the PSD is about 2.5 times of that under the AT PSM,which can effectively increase the PSD and the flexibility of external power supply location.Originality/value–The research content can effectively improve the PSD of traction power supply system and has important reference value for the engineering application of the scheme.

Application of Weighted Average Method in Evaluation System for Rural Cadre Distance Education

We elaborate the application method,process and effect of weighted average method in the examination and evaluation system for modern distance education of rural party members and cadres.The study shows that this method reflects the evaluation results objectively and comprehensively and plays a remarkable role in establishing and improving the examination and evaluation system,thus will have an important reference value for the development of modern distance education of rural party members and cadres in the future.

基于MCRASN的遥感影像变化检测

为了提升经配准高分辨率遥感影像对变化检测的精度,基于ChangeFormer提出了一种将移动卷积与相对注意力相结合的孪生网络(mobile convolution and relative attention Siamese network,MCRASN)。该网络以垂直布局结合移动卷积和相对注意力,构建多阶段组合编码器替换原网络编码器,高效地捕捉所需的多尺度细节特征和像素间相互关系信息,改进差异模块为1个可学习的距离度量模块进行距离计算,同时通过引入EFL(equalized focal loss)损失函数解决数据集正负样本失衡的问题以实现精确的变化检测。实验结果表明,所提出的MCRASN算法在LEVIRCD数据集上具有更好的变化检测性能,其精确率、召回率、F1得分和总体精度分别为93.94%、89.26%、91.54%和99.18%,优于先前的多种检测方法。

基于Abaqus二次开发的复杂结构寿命计算平台

临界距离理论适用于计算复杂结构的蠕变疲劳寿命,但在工程实践中该方法的计算效率很低。为解决这一问题,使用Python语言对Abaqus软件进行二次开发。所开发软件可以使用临界距离法计算结构的蠕变疲劳寿命,并提供多种功能以提高分析效率,包括模型信息提取、材料参数导入和计算结果输出等。通过对某型高压涡轮叶片进行分析计算验证了软件适用性。结果表明该软件可以有效简化临界距离法的步骤,实现对复杂结构蠕变疲劳寿命的高效计算,具有一定工程价值。

行进间地面机动目标射击诸元解算方法

针对地面机动目标运动模式未知、无源跟踪缺乏距离量测信息导致传统射击诸元解算方法解命中精度下降的问题,提出一种基于纯角度测量的行进间地面机动目标射击诸元解算方法。在传统固定参数的当前统计(CS)模型基础上,利用模糊推理动态调整机动频率,并根据加速度历史估计信息设置机动加速度方差,提高目标方位角的估计精度;在一次测距的基础上,基于简化刚体弹道模型,利用割弦迭代法计算出命中点坐标,并在每次迭代中利用虚拟脱靶量对射击诸元进行修正,减少对弹道方程的计算次数,提高射击诸元解算的实时性和精度。仿真结果表明,该方法有效可行,基于模型参数自适应的CS模型提高了目标角度跟踪的精度,基于虚拟脱靶量的迭代修正算法提高了诸元解算的实时性,解命中精度相对于传统射击诸元解算方法得到了显著改善。

适用于严苛正序助增系数计算的故障位置快速选取方法

针对相间距离保护整定计算中严苛正序助增系数对应故障位置的选取效率较低及精度不足的问题,提出适用于严苛正序助增系数计算的故障位置快速选取方法。首先,基于节点阻抗矩阵及矩阵元素的修改公式,推导了正序助增系数表达式,整理得到13类正序助增系数随故障位置移动的可能变化趋势。然后,通过研究正序助增系数随故障位置移动的变化规律,得到5条严苛正序助增系数对应故障位置的选取判据,提出一种适用于各类复杂网络结构的故障位置快速选取方法。最后,通过IEEE多节点标准测试系统验证了所提方法的有效性。故障位置选取精度高于规程选取方法,选取效率高于多点选取方法。

基于弗雷歇距离的光伏组件温度计算

使用相似度评估方法中的弗雷歇距离(Frechet distance)评估不同条件下的光伏组件输出特性,并通过对温度和辐照度的分析建立关系方程,基于该方程计算光伏组件温度。经过仿真实验分析以及实测数据验证,并与国际电工委员会(IEC)标准中所定义的测试方法进行对比,证明该方法在计算光伏组件的温度方面具有较高的准确度以及实用性。

基坑盖板下逆作车站地下连续墙托换破除技术

附属结构与地铁车站连通常需要对地下连续墙进行破除,当地下连续墙上设有临时承重盖板时破除的施工难度更大,风险更高。以某地铁盖挖逆作车站的地下连续墙破除施工为依托,提出了利用局部破除体作为临时竖向支撑进行托换破除的施工方法。首先,采用数值计算分析了不同托换间距对盖板结构体系的受力影响,综合施工进度和作业空间考虑,确定预留1m宽的临时托换柱和不大于12m的破除间距为控制指标,能够满足各受力结构体系在临时托换施工下的承载性能要求;其次,对盖板下地下连续墙破除及切割块转运施工进行了详细分析,给出了分块尺寸、切割块吊装、预留柱节点等关键施工环节的控制指标与做法。实施结果表明:利用既有地下连续墙作为临时托换结构进行破除地下连续墙的施工方法,安全可靠,施工速度快,成本经济。

基于哈希和编辑距离算法的SCD双层向量化与变更校验技术

针对智能变电站配置描述(substation configuration description,SCD)文件变更、智能变电站二次设备配置不清晰导致运维工作量剧增的问题,提出基于哈希和编辑距离算法的SCD双层向量化与变更校验技术。首先,考虑文件变更的启动与校验,应用节点元素、校验码与元素属性构建面向SCD文件解析的双层向量模型;其次,利用哈希算法将构建的文本向量模型转化为哈希字符串向量模型;然后,引入编辑距离算法分别计算原始文件与变更文件的双层向量模型相似度,基于第一层相似度比较构成第二层校验启动判据,基于第二层相似度结合回溯路径方法实现变更校验;最后,通过算例分析验证了所提算法的有效性。

天然气冷放空模拟及实验研究

天然气放空是输气管道生产运行过程中的重要环节,是压力、温度、放空流量都随着时间变化的复杂过程。基于放空管道的实际情况,对相关规范所推荐的计算方法进行改进完善。改进的模型考虑了出口临界流动和亚临界流动的放空计算,研究放空管阀门开度、天然气气体膨胀导致的内能变化对管道放空的影响。该模型的计算结果与工程实际中的管道放空数据大致吻合,为以后的生产调度和事故维抢修提供了技术支持。

基于多元种子选择的混合模糊测试方法

混合模糊测试结合了模糊测试与符号执行,使用模糊测试探索程序中的路径,并利用符号执行求解模糊测试难以突破的复杂约束,但现有混合模糊测试工作在选择符号执行的求解目标时未考虑两种技术之间的任务协作和符号执行的求解收益。针对上述问题,文中提出基于多元种子选择的混合模糊测试方法。利用程序控制流图对程序状态进行分析,对种子发现路径的能力进行量化,由符号执行来求解模糊测试难以探索到新路径的种子,从而形成两者之间的任务协作。利用目标点导向的思想量化种子挖掘漏洞的能力,使符号执行求解更有可能发现漏洞的种子。实验结果表明,相较于现有混合模糊测试工作,所提方法的整体路径发现数量提升了8.35%,整体漏洞发现数量提升了28.69%。

基于Bently-Hammer软件的长距离输水管道水锤防护模拟

基于Bently-Hammer软件对某实际工程中长距离输水系统进行建模,通过实际运行中的不同工况,模拟突发事件在管道与水泵间产生的水锤影响,同时针对系统内突发事件增加液压气动罐、缓闭止回阀等水锤消除措施加以改进,为实际工程提供有效抑制水锤破坏的技术保障。

基于Simhash算法的题库查重系统的设计与实现

Simhash算法是一种基于局部敏感哈希(LSH)的技术,以其快速的计算速度和高度的查重准确性而知名。该算法通过将文本特征转换为二进制码,进而通过计算这些二进制码之间的汉明距离来评估文本的相似度。在文本去重和重复文档检测等多个领域,Simhash算法已经展现出了显著的效果。鉴于此,将Simhash算法应用于题库查重具有很高的可行性和实际应用价值。

基于分时电价测算的电力市场交易运营研究

为了解决大型水电站电力交易中存在的分时价值量化难的问题,提出一种基于分时电价测算的电力市场交易运营方法。采用弗雷歇距离对多时间尺度交易分时价格逼近分析,获得水电站分时电力交易的特征;建立双边交易与集中交易规则,采用Stackelberg博弈模型求解最优的电力交易报价,在此基础上进行电力市场交易。在某河流域水电站应用所提方法,其电力交易价格准确率为96.6%。所提方法能有效提高电力市场交易价格预测的准确性,提升水电站的电力市场交易运营水平。