Ranking approach of cross-efficiency based on improved TOPSIS technique

The cross-efficiency evaluation method is reviewed which is developed as a data envelopment analysis （DEA） extensive tool. The cross-efficiency evaluation method is utilized to identify the decision making unit （DMU） with the best practice and to rank the DMUs by their respective cross-efficiency scores. The main drawbacks of the cross-efficiency evaluation method when the ultimate average cross-efficiency scores are used to evalu- ate and rank the DMUs are also pointed out. With the research gap, an improved technique for order preference by similarity to ideal solution （TOPSIS） is introduced to rank the crossfficiency by eliminating the average assumption. Finally, an empirical example is illustrated to examine the validity of the proposed method.

OPTIMIZATION ON ANTENNA PATTERN OF SPACEBORNE SAR WITH IMPROVED NSGA-Ⅱ

Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NSGA-Ⅱ), is applied on a spaceborne SAR antenna pattern design. The system consists of two objective functions with two constraints. Pareto fronts are generated as a result of multi-objective optimization. After being validated by a test problem ZDT4, the algorithms are used to synthesize spaceborne SAR antenna radiation pattern. The good results with low Ambi- guity-to-Signal Ratio (ASR) and high directivity are obtained in the paper.

On Significance of Cross-cultural Communication in International Business-Specified on Accounting Internationalization

There is limited information about intercultural communication during the process of accounting internationalization,and Chinese accounting still has a long way to go because of the disparity in accounting principles,business culture and so on.This paper talks about the necessity of accounting internationalization and the importance of intercultural communication skill,aiming at reminding people that a good command of intercultural communication skill is a must.Some suggestions are given in hope of contributing to cross-cultural communication during the process of Chinese accounting internationalization.

Safety evaluation for railway vehicles using an improved indirect measurement method of wheel–rail forces

The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to evaluate the running safety of railway vehicles. In this method, the equilibrium equations of a suspended wheelset are derived and the wheel-rail forces are then be obtained from measured suspension and inertia forces. This indirect method avoids structural modifications to the wheelset and is applicable to the long-term operation of railway vehicles. As the wheel-rail lateral forces at two sides of the wheelset are difficult to separate, a new derailment criterion by combined use of wheelset derailment coefficient and wheel unloading ratio is proposed. To illustrate its effectiveness, the indirect method is applied to safety evaluation of rail- way vehicles in different scenarios, such as the cross wind safety of a high-speed train and the safety of a metro vehicle with hunting motions. Then, the feasibility of using this method to identify wheel-rail forces for low-floor light rail vehicles with resilient wheels is discussed. The values identified by this method is compared with that by Simpack simulation for the same low-floor vehicle, which shows a good coincidence between them in the time domain of the wheelset lateral force and the wheel-rail vertical force. In addition, use of the method to determine the high-frequency wheel-rail interaction forces reveals that it is possible to identify the high-frequency wheel-rail forces through the accelerations on the axle box.

Stability analysis of wireless network with improved fluid model

Wireless communication is easily disturbed by unfortunate factors which drive the wireless environment unstable and complicated. Therefore, it is essential to consider these factors in stability analysis of the wireless network. However, wireless channel characteristics and packets collisions are neglected in the classical fluid model. A wireless TCP fluid model （WTFM） for stability analysis of wireless network is proposed based on cross layers, which not only makes the congestion control based on random early detection （RED） available for wireless network, but also provides a more accurate model to analyze the stability of wireless system theoretically. In the proposed model, active queue management, abnormality of wireless channels and packets collisions are taken into consideration. The comparisons between evaluating results from the WTFM and the practical performance from NS2 simulations validate the accuracy of the proposed WTFM in the perspectives of delay, dropping probability, throughput, sliding window size and queue length. A set of comparisons among the proposed WTFM, the classical fluid model and the convex optimization model are conducted. The results demonstrate that the proposed WTFM model performs better than other schemes in comprehensive aspects on capturing the characteristic of the wireless network and computing complexity.

Quantifying the effect of improved school and residential building codes for tornadoes in community resilience

Tornadoes can destroy or severely damage physical infrastructure including buildings in a community.This can result in direct losses but also indirect losses such as the closure of key social institutions reverberating further through the community(e.g.,schools).Despite significant losses in past events,building codes and standards have not previously included tornado hazards because of the relatively low probability of a direct strike.The recent release of the ASCE 7-22 standard considers tornadoes for Risk Category 3 and 4 buildings,i.e.ranging from schools to critical facilities.This study proposes a series of design combinations of a reinforced masonry school building with different performance targets intended to enable schools to reopen sooner.Tornado fragilities were developed for a school building having improved designs using tornado loads determined based on the new tornado chapter in ASCE 7-22,and then integrated into a community level model with school attendance zones to examine the effect.The ultimate goal in this study is to investigate the effect of improving school building designs would have on maintaining school continuity(and more rapid return)for school children.

Improvement in the calculation of anti-Stokes energy transfer and experimental justification based on Er_(0.01)Yb_xY_(1 0.01 x)VO_4 crystal

The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{△E/kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er0.01YbxY1-0.01-xVO4 crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time.

Variance Reduction Technique for Estimating Value-at-Risk based on the Cross - Entropy

Value-at-Risk （VaR） estimation via Monte Carlo （MC） simulation is studied here. The variance reduction technique is proposed in order to speed up MC algorithm. The algorithm for estimating the probability of high portfolio losses （more general risk measure） based on the Cross - Entropy importance sampling is developed. This algorithm can easily be applied in any light- or heavy-tailed case without an extra adaptation. Besides, it does not loose in the performance in comparison to other known methods. A numerical study in both cases is performed and the variance reduction rate is compared with other known methods. The problem of VaR estimation using procedures for estimating the probability of high portfolio losses is also discussed.

一种改进搜索的A-star算法

针对移动机器人在大规模复杂环境中规划速度慢、计算量大等问题,提出一种改进A-star路径规划算法。引入双向跨节点搜索机制,从原始起点和终点开始,分别以对向当前节点作为目标点进行搜索,优化寻路方向并缩减搜索节点数量;改进遇到障碍物时的搜索方法引入跳变概念,当扩展节点处于障碍物内时该节点认作无效节点,发生跳变,从无效节点处向垂直于无效节点扩展方向的两个方向搜索,直至搜索至非障碍物区,使快速脱离障碍物区域;改进节点评价方法采用分段评价方式,正常扩展阶段将扩展节点加入open表,并对open表中节点评价,当发生跳变时将跳变节点加入jump表并清空open表,然后对jump中节点表进行评价,该操作使得评价节点始终保持在一定数量,减少不必要节点的计算,节约内存占用,使得搜索效率不会因为扩展节点增多而降低。算法有效性在Matlab中仿真实现,通过对比不同算法在不同障碍物栅格地图中的仿真结果,论文改进算法计算节点更少,效率更高。

基于IEWT-MOMEDA-FSC的滚动轴承故障诊断

针对滚动轴承故障信号常伴有噪声干扰且故障特征难以提取的问题,本文提出一种基于改进经验小波变换(IEWT)、多点优化最小熵解卷积(MOMEDA)和快速谱相关(FSC)的滚动轴承故障诊断方法.首先,将原始信号进行快速谱相关分析得到增强包络谱,通过增强包络谱的极值点来自适应地划分频谱,以分割的频谱为边界构建小波滤波器组将信号分解为多个IMF分量,利用相关峭度准则筛选出有效的分量进行叠加;其次,用MOMEDA对其进行降噪处理,将降噪后的信号进行快速谱相关分析,得到增强包络谱图;最后,将增强包络谱图中幅值较高的频率与故障频率对比,判定其失效形式,用所提出的方法对实测轴承故障信号进行分析验证.结果表明,所提出的方法能有效降低噪音干扰且增强信号故障冲击特性,在噪声环境下具有较强的故障特征提取能力.

计及相关性及改进交叉熵法的电-热互联综合能源系统风险评估

电–热互联综合能源系统负荷及风电随机性加剧,导致系统运行风险水平增加。为解决上述问题,提出了一种计及变量相关性及改进交叉熵法的电–热互联综合能源系统风险评估方法。首先,构建了电–热互联综合能源系统潮流模型,采用高斯混合模型建立风电出力不确定性场景,基于概率潮流对系统风险进行评估。接着,针对现有单峰最优抽样函数的交叉熵法在计算多边越限情况下的不足,提出了基于多峰最优抽样函数的改进交叉熵法对系统风险指标进行计算。进一步的,针对目前交叉熵法难以计及变量间的相关性,通过等价转换将相关性样本进行独立性转换,从而有效解决了这一难题。最后,在巴厘岛32节点热网和改进的IEEE-33节点配电网组成的电–热互联综合能源系统中验证了所提方法的有效性。

基于改进的十字-菱形搜索算法的运动估计

通过对序列运动矢量概率分布分析,发现了该概率分布的方向性特性,提出了一种新的块匹配运动估计算法——改进的十字-菱形搜索(ICDS)算法。该算法在搜索的初始阶段使用小十字搜索模型对小运动矢量进行搜索,强调运动矢量分布的中心偏置特征;而对于大的运动矢量使用具有方向性的菱形搜索模型进行搜索,强调运动矢量分布的方向性,从而提高了运动矢量的搜索速度。该算法与菱形(DS)和十字-菱形块(CDS)匹配算法相比,在保证搜索质量的前提下,其搜索速度分别可以提高60%和35%。理论分析和实验结果证明ICDS算法有效,且具有较强的鲁棒性。

HTR-ESS的堆芯物理仿真方法研究

为满足高温气冷堆工程模拟仿真系统(HTR-ESS)中实时的要求,研究开发了三维圆柱几何堆芯多群中子时空动力学改进准静态方法模拟计算程序,使中子动力学程序满足模拟过程的实时要求。模型利用拟合公式计算宏观截面,使截面可实时反映堆芯状态,与堆芯热工形成反馈。针对高温气冷堆中控制棒的特点,提出使用等效吸收体的方法对控制棒进行等效,等效方法避免了在计算中出现控制棒移动与网格不匹配的问题。最后给出动态过程的简单模拟结果,显示了建立的堆芯物理实时计算模型满足设计条件和要求。

基于学生发展的学校自我诊断中大数据的有效运用--学校自我诊断研究之三

在基于学生发展的学校自我诊断中,有效运用大数据是实现科学诊断的关键。首先,通过指数算法,判断学校在核心要素上的目标达成度;其次,通过关联横纵数据,找准关键问题,全面深入分析数据以挖掘学校的优势和问题;再次,通过多角度的数据互证,发现问题的实质和突破口;最后,结合多种形式的数据,如师生的主观留言、访谈及课堂观察等,寻找问题改进的策略与方法。四个环节层层深入,并持续追踪大数据的发展,可以帮助学校清晰地描绘出发展进步的轨迹。

钢-混凝土混合变截面连续梁桥钢箱梁段合理长度研究

为简便估算恒载作用下钢-混凝土混合变截面连续梁桥的合理钢箱梁段长度,基于现有三弯矩方程推导适用于变截面连续梁的改进三弯矩方程;建立基于改进三弯矩方程的变截面连续梁弯矩简化计算方法,构建不同跨径的变截面钢-混凝土混合标准连续梁桥,并给出其钢箱梁段合理长度的预估公式.研究结果表明:基于改进三弯矩方程的变截面连续梁弯矩计算结果与有限元计算结果的偏差小于10%,可以便捷且准确地计算恒载下变截面连续梁弯矩;预估公式计算得到的钢箱梁段合理长度与实桥使用的钢箱梁段长度之间的误差在12.5%以内,预估公式具有良好适用性.

基于改进LS-ESPRIT算法的GTD模型参数估计与RCS重构

针对传统LS-ESPRIT算法在估计GTD模型参数时抗噪效果差,估计精度不高这一问题,该文提出了一种改进的LS-ESPRT算法,有效地提高了算法的参数估计性能与抗噪性。首先,根据雷达目标的回波数据构建Hankel矩阵;其次,采用核范数凸优化方法对上述Hankel矩阵进行降噪处理,得到低秩的重构Hankel矩阵;最后,利用传统的LS-ESPRIT算法对降噪后的数据进行处理,估计出GTD模型参数。基于改进算法与传统算法分别得到重构RCS,并针对不同带宽对参数估计精度的影响作以仿真探究。仿真结果表明,与传统LS-ESPRIT算法与传统TLS-ESPRIT算法相比,改进LS-ESPRIT算法的参数估计性能更高,抗噪性更强,且重构RCS的幅值与相角误差更小。对不同带宽下的参数估计精度也进行了探究,并得出:带宽越大,估计精度越高。

基于改进C-Logit模型的三峡翻坝运输分担率研究

三峡枢纽船舶积压日益严重,翻坝是解决三峡枢纽船舶积压的有效策略.结合三峡枢纽翻坝运输路径特点,选取能改善传统Logit模型IIA和IID弊端的改进C-Logit模型为基础模型,引入考虑时间成本和翻坝补贴在内的广义货运费用概念,构建三峡翻坝运输分担率模型.在此模型基础上研究并分析重庆至上海集装箱和商品车翻坝运输分担率和其翻坝补贴之间的量化关系.分析表明,翻坝补贴措施能有效地增加翻坝运输分担率,在各应急等级下,每提供100元/TEU或100元/车的翻坝补贴就能实现集装箱约6.2%或商品车约21.2%的转移率.

基于改进K-Means聚类与水平集的木材横截面管孔分割

针对管孔随机分布且大小不一导致管孔分割鲁棒性不高,及木纤维、木射线和轴向薄壁组织等噪声对管孔分割效果影响较大的问题,本研究提出一种改进K-Means聚类与水平集的木材横截面管孔分割算法。采用改进K-Means聚类对管孔区域进行粗分割,有效地区分管孔区域与木纤维、木射线以及轴向薄壁组织等噪声区域。再对粗分割结果采用水平集算法进行精分割。实验结果表明,平均每张木材横截面微观图像有98.8%的管孔被准确有效地分割出来,且分割出的管孔与实际管孔基本吻合。相比之下,本研究提出的改进分割算法较其他算法,每张木材微观图像的平均管孔分割准确率提高了1.7%。该算法有效地解决传统K-Means聚类算法在图像分割时噪声影响大和初始聚类中心的随机性问题,在针对大小不一且随机分布的管孔分割过程中鲁棒性更高,具有良好的分割性能。

A new method of quality improvement for quadrilateral mesh based on small polygon reconnection

In this paper, a new method of topological cleanup for quadrilateral mesh is presented. The method first selects a patch of mesh around an irregular node. It then seeks the best connection of the selected patch according to its irregular valence using a new topological operation： small polygon reconnection （SPR）. By replacing the original patch with an optimal one that has less irregular valence, mesh quality can be improved. Three applications based on the proposed approach are enumerated： （1） improving the quality of a quadrilateral mesh, （2） converting a triangular mesh to a quadrilateral one, and （3） adapting a triangle generator to a quadrilateral one. The presented method is highly effective in all three applications.

基于IBA-KELM模型的TCT光伏阵列故障诊断研究

针对光伏阵列的开路故障、短路故障、老化故障和局部阴影故障,提出了一种基于核极限学习机KELM(kernel extreme learning machine)的光伏阵列故障诊断方法,并采用改进的蝙蝠算法IBA(improved bat algorithm)对核极限学习机模型的参数进行优化来提高模型的诊断准确率。为避免蝙蝠算法陷入局部最优并加快在参数寻优过程中的收敛速度,引入Levy飞行策略并在速度更新公式中引入指数递减的惯性权重。通过全连接TCT(total-crosstied)结构光伏阵列的故障数据验证表明,与BA-KELM,PSO-KELM、PSO-ELM模型相比,IBA-KELM模型在参数优化过程中收敛速度更快,优化后模型诊断精度也更高。