多元回归分析的间接平差算法

回归分析是利用大量的观测数据来确定变量之间相关关系的一种数学方法。但在求回归系数时计算复杂，易出错。提出用间接平差的方法来计算回归系数，简化了计算过程。给出了一套计算方法，并通过计算实例验证了该方法的有效性。     

轮机工程专业船舶电气教学改革探讨

随着我国轮机人员“机电合一”,以及海船船员适任考试新大纲的施行,对轮机人员船舶电气方面的知识要求越来越高,而毕业生尚不能完全满足要求的现象。本文分析了当前船舶电气课程教学中存在教材覆盖面不够、不能满足工作需要以及现有课程实践性差的问题,探讨了船舶电气教学改革的思路和方法。并针对性地对广东海洋大学轮机专业的船舶电气实验教学提出了自己的改进意见。     

Numerical simulation of aerodynamic performance of a couple multiple units high-speed train

In order to determine the effect of the coupling region on train aerodynamic performance, and how the coupling region affects aerodynamic performance of the couple multiple units trains when they both run and pass each other in open air, the entrance of two such trains into a tunnel and their passing each other in the tunnel was simulated in Fluent 14.0. The numerical algorithm employed in this study was verified by the data of scaled and full-scale train tests, and the difference lies within an acceptable range. The results demonstrate that the distribution of aerodynamic forces on the train cars is altered by the coupling region; however, the coupling region has marginal effect on the drag and lateral force on the whole train under crosswind, and the lateral force on the train cars is more sensitive to couple multiple units compared to the other two force coefficients. It is also determined that the component of the coupling region increases the fluctuation of aerodynamic coefficients for each train car under crosswind. Affected by the coupling region, a positive pressure pulse was introduced in the alternating pressure produced by trains passing by each other in the open air, and the amplitude of the alternating pressure was decreased by the coupling region. The amplitude of the alternating pressure on the train or on the tunnel was significantly decreased by the coupling region of the train. This phenomenon did not alter the distribution law of pressure on the train and tunnel; moreover, the effect of the coupling region on trains passing by each other in the tunnel is stronger than that on a single train passing through the tunnel.     

更换公路旧桥支座的顶升方案

对更换支座的方法进行了分析总结,并在河北省新乐市-沙河大桥施工中,提出了一种简单易行、节约投资的支座更换方法-兜子顶升法;对该法的设计、作用原理进行了阐述,并介绍了其施工过程,为今后更换桥梁支座提供参考.     

Classification decision tree algorithm assisting in diagnosing solitary pulmonary nodule by SPECT/CT fusion imaging

Objective To develop a classification tree algorithm to improve diagnostic performances of 99mTc-MIBI SPECT/CT fusion imaging in differentiating solitary pulmonary nodules (SPNs). Methods Forty-four SPNs, including 30 malignant cases and 14 benign ones that were eventually pathologically identified, were included in this prospective study. All patients received 99Tcm-MIBI SPECT/CT scanning at an early stage and a delayed stage before operation. Thirty predictor variables, including 11 clinical variables, 4 variables of emission and 15 variables of transmission information from SPECT/CT scanning, were analyzed independently by the classification tree algorithm and radiological residents. Diagnostic rules were demonstrated in tree-topology, and diagnostic performances were compared with Area under Curve (AUC) of Receiver Operating Characteristic Curve (ROC). Results A classification decision tree with lowest relative cost of 0.340 was developed for 99Tcm-MIBI SPECT/CT scanning in which the value of Target/Normal region of 99Tcm-MIBI uptake in the delayed stage and in the early stage, age, cough and specula sign were five most important contributors. The sensitivity and specificity were 93.33% and 78. 57e, respectively, a little higher than those of the expert. The sensitivity and specificity by residents of Grade one were 76.67% and 28.57%, respectively, and AUC of CART and expert was 0.886±0.055 and 0.829±0.062, respectively, and the corresponding AUC of residents was 0.566±0.092. Comparisons of AUCs suggest that performance of CART was similar to that of expert (P=0.204), but greater than that of residents (P<0.001). Conclusion Our data mining technique using classification decision tree has a much higher accuracy than residents. It suggests that the application of this algorithm will significantly improve the diagnostic performance of residents.     

急性肝衰竭大鼠血液及胃肠组织中胃动素、胃泌素含量的变化

目的探讨胃动素(MTL)、胃泌素(GAS)在急性肝衰竭(ALF)大鼠血液及胃肠组织中的含量变化及其与肝性胃肠功能障碍的相关性。方法用硫代乙酰胺(TAA)复制出ALF大鼠模型,观察其一般情况及肝脏生化指标,放射免疫分析法(RIA)测定其血液及胃肠黏膜组织中MTL和GAS的含量。结果①模型组大鼠血液及胃黏膜组织中MTL、GAS含量及肠黏膜组织中MTL含量明显升高,与正常对照组比较差异有统计学意义(P<0.01),肠黏膜组织中GAS含量下降,但无统计学意义;②直线相关分析显示,模型组血浆MTL、GAS含量与肝功能指标(ALT、AST)呈显著正相关关系(P<0.01);③模型组大鼠造模后(24、36、48h),随ALF病情及肝性胃肠功能障碍的进展,MTL、GAS含量呈进行性升高。结论血中MTL、GAS含量测定既可作为判断肝功能损伤的指标,亦可作为判断ALF时胃肠功能障碍的指标。     

立交工程软弱土层基坑防护结构受力分析

随着城市规模的不断扩大和铁路的快速发展,市政道路与铁路立交工程逐渐增多。高规格的市政道路使铁路地道越做越大,同时,新建高速铁路严格的沉降控制对工程实施提出了更高的要求。为了确保市政设施及铁路的安全,必须对越做越大的基坑工程进行有效的防护。以典型的高水位、软弱土层、大面积的基坑工程为例,采用钻孔灌注桩为防护结构主体,用冠梁、桩间腰梁、水平内撑、水平斜撑等方式对基坑工程进行了加强。对施工过程中结构的受力与变形情况进行了详细的分析。经现场实际实施,支护系统稳定安全。     

机构投资者持股与上市公司信息披露行为研究

研究采用我国上市公司2005年至2008年会计年报数据,实证检验机构投资者持股对于多角度公司信息披露行为的影响。研究发现机构持股比例越高的公司年报披露越及时,但是持有同一家上市公司的机构数量越多反而会延迟年报的披露;同时还发现机构持股对于上市公司年报的审计意见类型和年报的补充公告影响并不显著,说明我国机构投资者对于上市公司的内部治理作用还十分有限。     

山西海事：夯实基础 建立长效机制

山西地处华北西部的黄土高原东翼,属于典型的非水网地区,全省通航总里程1234公里,其中,黄河流经山西省4个市、19个县（市、区）,通航里程971公里,是与蒙、陕、豫的天然分界线,沿黄地区经济发展缓慢,自然条件恶劣,渡运是两岸百姓生活、农作、交流的主要运输工具之一,具有点多、线长、面广的特点,船员大多数属于当地村民,     

Human machine collaborative support scheduling system of intelligence information from multiple unmanned aerial vehicles based on eye tracker

Many human-machine collaborative support scheduling systems are used to aid human decision making by providing several optimal scheduling algorithms that do not take operator’s attention into consideration. However, the current systems should take advantage of the operator’s attention to obtain the optimal solution. In this paper, we innovatively propose a human-machine collaborative support scheduling system of intelligence information from multi-UAVs based on eye-tracker. Firstly, the target recognition algorithm is applied to the images from the multiple unmanned aerial vehicles (multi-UAVs) to recognize the targets in the images. Then, the support system utilizes the eye tracker to gain the eye-gaze points which are intended to obtain the focused targets in the images. Finally, the heuristic scheduling algorithms take both the attributes of targets and the operator’s attention into consideration to obtain the sequence of the images. As the processing time of the images collected by the multi-UAVs is uncertain, however the upper bounds and lower bounds of the processing time are known before. So the processing time of the images is modeled by the interval processing time. The objective of the scheduling problem is to minimize mean weighted completion time. This paper proposes some new polynomial time heuristic scheduling algorithms which firstly schedule the images including the focused targets. We conduct the scheduling experiments under six different distributions. The results indicate that the proposed algorithm is not sensitive to the different distributions of the processing time and has a negligible computational time. The absolute error of the best performing heuristic solution is only about 1%. Then, we incorporate the best performing heuristic algorithm into the human-machine collaborative support systems to verify the performance of the system.