人脸识别系统在重庆轨道交通公安系统中的应用

结合重庆轨道交通公安分局人脸识别系统建设的情况,分析了基于视频流的人脸识别系统在重庆轨道交通中的应用,重点阐述了人脸识别系统在重庆轨道交通公安系统中的基本构成,并详细分析了人脸识别系统在重庆轨道交通公安系统中的重要作用.     

熔融石英砂动力特性动三轴试验

为探究振动荷载作用下熔融石英砂液化破坏过程中动变形和动强度变化规律, 促进透明土技术在岩土工程动力特性可视化模型试验中的推广和应用, 对构成透明砂土骨架结构的典型粒径(0.5~1.0 mm)熔融石英砂开展饱和试样动三轴试验; 研究了不同围压、加载频率和动应力比等试验条件下熔融石英砂试样的累积轴向应变、动孔压发展模式、动应力衰减、动弹性模量和阻尼比的变化规律, 并将试验结果与相同级配的标准砂进行了对比。分析结果表明: 熔融石英砂累积轴向应变随动应力比的增大呈现出由稳定型向破坏型转变的趋势, 加载频率为0.5~1.5 Hz时, 临界动应力比为0.150~0.175, 小于标准砂的0.200~0.225;升高围压、增大动应力比、降低加载频率会加快试样塑性应变累积, 缩短液化破坏时间; 熔融石英砂孔压发展模式随围压增大逐渐由Seed孔压模型向指数型过渡, 增大加载动应力会加剧液化破坏后孔压的振动幅度; 相同动应力比下, 熔融石英砂与标准砂的动应力与动应变呈现线性相关, 在围压大于200 kPa时, 二者动应力衰减幅度随围压的增大而逐渐减小; 熔融石英砂的动弹性模量和阻尼比表现为线性关系, 动弹性模量随动应变的增大呈现出双曲线型减小的趋势, 并随围压的增大而增大; 阻尼比随动应变的增加先增大后基本稳定在0.22, 发展曲线受围压影响较小。      

CT reconstruction with priori MRI images through multi-group datasets expansion

Computed tomography (CT) reconstruction with a well-registered priori magnetic resonance imaging (MRI) image can improve reconstruction results with low-dose CT, because well-registered CT and MRI images have similar structures. However, in clinical settings, the CT image of patients does not always match the priori MRI image because of breathing and movement of patients during CT scanning. To improve the image quality in this case, multi-group datasets expansion is proposed in this paper. In our method, multi-group CT-MRI datasets are formed by expanding CT-MRI datasets. These expanded datasets can also be used by most existing CT-MRI algorithms and improve the reconstructed image quality when the CT image of a patient is not registered with the priori MRI image. In the experiments, we evaluate the performance of the algorithm by using multi-group CT-MRI datasets in several unregistered situations. Experiments show that when the CT and priori MRI images are not registered, the reconstruction results of using multi-group dataset expansion are better than those obtained without using the expansion.     

Seafarers’ perceptions of competency in risk assessment and management: an empirical study

Past analysis of accident investigations suggest an absence of or inadequate practices of risk assessment and management on board vessels. Although the International Management Code for the Safe Operation of Ships and for Pollution Prevention (ISM Code) requires that the risk management process must not only be correctly formulated and implemented but also be periodically evaluated in order to verify that these objectives are attained, the correct and effective implementation and application of the process cannot be achieved without active involvement of competent seafarers on board. Due to the limited investigation of seafarers’ competencies in risk management, the reasons for the inadequacies in the process that are leading to accidents were not evident. Hence, using a survey, this paper conducted a pilot study investigating seafarers’ perceptions of competency in the various components of the risk management process conducted on board vessels. The findings of this paper suggest an overall satisfaction with the risk assessment process. However, there is certainly room for improvement as far as seafarers’ performance is concerned. The findings of this paper provided valuable insights into the current training regimes in the area of risk assessment and management paving the way towards enhanced safety procedures on board vessels.     

Automatic outer surface extraction of femoral head in CT images

Computer-aided hip surgery planning and implant design applications require accurate segmentation of femoral head and proximal acetabulum. An accurate outer surface extraction of femoral head using marching cubes algorithm remains challenging due to deformed shapes and extremely narrow inter-bone regions. In this paper, we present an automatic and fast approach for segmentation of femoral head and proximal acetabulum which leads to accurate and compact representation of femoral head using marching cubes algorithm. At first, valley-emphasized images are constructed from original images so that valleys stand out in high relief. Otsu’s multiple thresholding technique is applied to seperate the images into bone and non-bone classes. Region growing method and threedimensional (3D) morphological operations are performed to fill holes in the bone. In the reclassification process, the bone regions are further segmented, and the boundaries of the bone regions are further refined based on Bayes decision rule. Finally, marching cubes algorithm is applied to reconstruct a 3D model and extract the outer surface of femoral head and proximal acetabulum. Experimental results show that this method is an accurate segmentation technique for femoral head and proximal acetabulum and it can be applied as a tool in medical practice.     

Comparison on travel scheduling between driving and walking trips by habitual car users

Research on walking behavior has become increasingly more important in the field of transportation in the past decades. However, the study of the factors influencing the scheduling decisions related to walking trips and the exploration of the differences between travel modes has not been conducted yet. This paper presents a comparison of the scheduling and rescheduling decisions associated with car driving trips and walking trips by habitual car users using a data set collected in Valencia (Spain) in 2010. Bivariate probit models with sample selection are used to accommodate the influence of pre-planning on the decision to execute a travel as pre-planned or not. The explicative variables considered are: socio-economic characteristics of respondents, travel characteristics, and facets of the activity executed at origin and at destination including the scheduling decisions associated with them. The results demonstrate that a significant correlation exists between the choices of pre-planning and rescheduling for both types of trips. Whether for car driving or walking trips, the scheduling decisions associated with the activity at origin and at destination are the most important explicative factors of the trip scheduling and rescheduling decisions. However, the rescheduling of trips is mainly influenced by modifications in the activity at destination. Some interesting differences arise regarding the rescheduling decision processes between travel modes: if pre-planned, walking trips are less likely to be modified than car driving trips, showing a more rigid rescheduling behavior.     

太古供暖隧道配套附属设施设计方案

针对太古供暖隧道运营期间散热、维护、巡检和灾害处置特点,以保障采暖季管道、管道自控设备的正常运转,保护巡检人员的人身安全,保证管网自控设备在火灾或崩管等恶性事故下仍能有效动作为目地,提出合理的配套附属设施构成和方案,旨在为同类工程设计提供借鉴。     

广西交通科技资源共享平台建设探讨

文章针对广西交通科技项目管理系统现状,分析了建设交通科技资源共享平台的必要性,阐述了交通科技资源共享平台建设的关键技术、创新点及主要内容,指出该共享平台的建设可改善和提高交通运输科技项目质量及监管水平。     

关于大学生心理健康教育课程的几点思考

大学生心理健康教育课程教学的目的是培养学生健康的心理和良好的心理素质,使其在思想认识、知识和技能三个层面学有所获。课程教学应遵循理论与实践相结合、教师讲授与学生体验相结合,通过课堂讲授、小组讨论与典型案例分析、心理素质训练与拓展等体验式教育方法进行教学;采用理论效果评估与实际操作效果评估相结合的方式对课程效果进行评估。     

Hybrid process of fabricating high-quality micro wine-glass fused silica resonators

A new hybrid method, which combines improved glass-blown technology with wet etching, is reported to fabricate micro wine-glass resonators with high-quality fused silica. The optimum placement is compared to achieve the resonators with good shell shape. The typical shell diameter is about 4mm and its thickness covers from dozens to hundreds of micrometers. The etching rates in corrosion solutions with different ratios and at different thicknesses of hemispherical shells are studied. We also conclude how to precisely control the thickness. The corrosion solutions with different ratios of HF solution to NH₄F solution make the spherical shells rougher in different degrees. The best roughness is 0.581 nm in the 1: 8 ratio corrosion solution while the original roughness is 0.537 nm. This fact shows that the resonator remains atomically smooth surface. Based on the glassblowing spherical fused silica structure, the thickness of the resonator is effectively controlled by buffered oxide etch (BOE) technology according to the measured etching rate. The measured resonant frequency of the hemispherical shell at ambient pressure and room temperature is 1.75 kHz of rocking mode which is close to the simulated frequency. Using such a low-cost hybrid approach, we can fabricate high-quality microscale resonators in batch.