Transorbital craniocerebral injury is a relatively rare type of penetrating head injury that poses a significant threat to the ocular and cerebral structures.^([1])The clinical prognosis of transorbital craniocerebral...Transorbital craniocerebral injury is a relatively rare type of penetrating head injury that poses a significant threat to the ocular and cerebral structures.^([1])The clinical prognosis of transorbital craniocerebral injury is closely related to the size,shape,speed,nature,and trajectory of the foreign object,as well as the incidence of central nervous system damage and secondary complications.The foreign objects reported to have caused these injuries are categorized into wooden items,metallic items,^([2-8])and other materials,which penetrate the intracranial region via fi ve major pathways,including the orbital roof (OR),superior orbital fissure (SOF),inferior orbital fissure(IOF),optic canal (OC),and sphenoid wing.Herein,we present eight cases of transorbital craniocerebral injury caused by an unusual metallic foreign body.展开更多
为了提高图像拼接速度并满足高分辨率图像的实时拼接需求,提出了一种基于ORB(Oriented Fast and Rotated Brief)算法和MSAC(M-estimator Sample Consensus)算法的快速图像拼接方法。ORB算法特征匹配速度快,能够满足实时性要求。首先采用...为了提高图像拼接速度并满足高分辨率图像的实时拼接需求,提出了一种基于ORB(Oriented Fast and Rotated Brief)算法和MSAC(M-estimator Sample Consensus)算法的快速图像拼接方法。ORB算法特征匹配速度快,能够满足实时性要求。首先采用ORB算法进行图像特征点提取;然后,采用MSAC算法对匹配点对进行优化,剔除图像拼接中的伪匹配点对,通过正确的匹配点对求解图像变换矩阵;最后,采用双线性插值融合算法消除可见接缝并去除拼接痕迹。实验结果表明,本文方法在保证图像拼接质量的同时具有更快的拼接速度。展开更多
利用计算机视觉对桥梁结构进行位移测量,常见的方法有特征点算法和光流法。为解决光照变化对光流法的精度影响,以及特征点法难以对目标进行实时跟踪等问题,以定向FAST与旋转BRIEF(oriented FAST and rotated BRIEF,ORB)特征点算法提取...利用计算机视觉对桥梁结构进行位移测量,常见的方法有特征点算法和光流法。为解决光照变化对光流法的精度影响,以及特征点法难以对目标进行实时跟踪等问题,以定向FAST与旋转BRIEF(oriented FAST and rotated BRIEF,ORB)特征点算法提取目标特征点,并结合LK(Lucas-Kanade)光流法进行跟踪。通过两种算法的互补融合,并设定周期性更新策略,有效减少误差积累。在室内进行了钢板梁模型激振试验,探讨光照变化对算法性能的影响。将算法得到的位移数据与激光位移计测量结果进行对比,以验证其准确性。此外,还将该算法与FAST-LK、SIFT-LK、Shi-Tomasi-LK、siamRPN++等算法进行比对分析。结果表明:该算法得到的位移曲线拟合程度在95%以上,误差控制在5%之内,验证了其可行性,同时,试验表明该方法对光照变化具有一定的鲁棒性,并能达到实时性的要求。展开更多
CORBA (Common Object Request Broker Architecture) provides 16 Common Object Services for distributed application development, but none of them are fault tolerance related services. In this paper, we propose a replica...CORBA (Common Object Request Broker Architecture) provides 16 Common Object Services for distributed application development, but none of them are fault tolerance related services. In this paper, we propose a replicated object based Fault Tolerant Object Service (FTOS) for CORBA environment. Two fault tolerant mechanisms are provided in FTOS including dynamic voting mechanism and object replication mechanism. The dynamic voting mechanism uses majority voting strategy to ensure object state consistency in failure situations. The object replication mechanism can help system administrators to replicate and start up objects easily. Our implementation provides a library according to the style of COSS. With this library, programmers can develop distributed applications with fault tolerance capability very easily.展开更多
As the number of space objects(SO)increases,collision avoidance problem in the rendezvous tasks or reconstellation of satellites with SO has been paid more attention,and the dangerous area of a possible collision shou...As the number of space objects(SO)increases,collision avoidance problem in the rendezvous tasks or reconstellation of satellites with SO has been paid more attention,and the dangerous area of a possible collision should be derived.In this paper,a maneuvering method is proposed for avoiding collision with a space debris object in the phasing orbit of the initial optimal solution.Accordingly,based on the plane of eccentricity vector components,relevant dangerous area which is bounded by two parallel lines is formulated.The axises of eccentricity vector system pass through the end of eccentricity vector of phasing orbit in the optimal solution,and orientation of axis depends on the latitude argument where a collision will occur.The dangerous area is represented especially with the graphical dialogue,and it allows to find a compromise between the SO avoiding and the fuel consumption reduction.The proposed method to solve the collision avoidance problem provides simplicity to calculate rendezvous maneuvers,and possibility to avoid collisions from several collisions or from“slow”collisions in a phasing orbit,when the protected spacecraft and the object fly dangerously close to each other for a long period.展开更多
文摘Transorbital craniocerebral injury is a relatively rare type of penetrating head injury that poses a significant threat to the ocular and cerebral structures.^([1])The clinical prognosis of transorbital craniocerebral injury is closely related to the size,shape,speed,nature,and trajectory of the foreign object,as well as the incidence of central nervous system damage and secondary complications.The foreign objects reported to have caused these injuries are categorized into wooden items,metallic items,^([2-8])and other materials,which penetrate the intracranial region via fi ve major pathways,including the orbital roof (OR),superior orbital fissure (SOF),inferior orbital fissure(IOF),optic canal (OC),and sphenoid wing.Herein,we present eight cases of transorbital craniocerebral injury caused by an unusual metallic foreign body.
文摘为了提高图像拼接速度并满足高分辨率图像的实时拼接需求,提出了一种基于ORB(Oriented Fast and Rotated Brief)算法和MSAC(M-estimator Sample Consensus)算法的快速图像拼接方法。ORB算法特征匹配速度快,能够满足实时性要求。首先采用ORB算法进行图像特征点提取;然后,采用MSAC算法对匹配点对进行优化,剔除图像拼接中的伪匹配点对,通过正确的匹配点对求解图像变换矩阵;最后,采用双线性插值融合算法消除可见接缝并去除拼接痕迹。实验结果表明,本文方法在保证图像拼接质量的同时具有更快的拼接速度。
文摘利用计算机视觉对桥梁结构进行位移测量,常见的方法有特征点算法和光流法。为解决光照变化对光流法的精度影响,以及特征点法难以对目标进行实时跟踪等问题,以定向FAST与旋转BRIEF(oriented FAST and rotated BRIEF,ORB)特征点算法提取目标特征点,并结合LK(Lucas-Kanade)光流法进行跟踪。通过两种算法的互补融合,并设定周期性更新策略,有效减少误差积累。在室内进行了钢板梁模型激振试验,探讨光照变化对算法性能的影响。将算法得到的位移数据与激光位移计测量结果进行对比,以验证其准确性。此外,还将该算法与FAST-LK、SIFT-LK、Shi-Tomasi-LK、siamRPN++等算法进行比对分析。结果表明:该算法得到的位移曲线拟合程度在95%以上,误差控制在5%之内,验证了其可行性,同时,试验表明该方法对光照变化具有一定的鲁棒性,并能达到实时性的要求。
文摘CORBA (Common Object Request Broker Architecture) provides 16 Common Object Services for distributed application development, but none of them are fault tolerance related services. In this paper, we propose a replicated object based Fault Tolerant Object Service (FTOS) for CORBA environment. Two fault tolerant mechanisms are provided in FTOS including dynamic voting mechanism and object replication mechanism. The dynamic voting mechanism uses majority voting strategy to ensure object state consistency in failure situations. The object replication mechanism can help system administrators to replicate and start up objects easily. Our implementation provides a library according to the style of COSS. With this library, programmers can develop distributed applications with fault tolerance capability very easily.
基金This work is supported and funded by NSFC(Natural Science Foundation of China)[No.51905272].
文摘As the number of space objects(SO)increases,collision avoidance problem in the rendezvous tasks or reconstellation of satellites with SO has been paid more attention,and the dangerous area of a possible collision should be derived.In this paper,a maneuvering method is proposed for avoiding collision with a space debris object in the phasing orbit of the initial optimal solution.Accordingly,based on the plane of eccentricity vector components,relevant dangerous area which is bounded by two parallel lines is formulated.The axises of eccentricity vector system pass through the end of eccentricity vector of phasing orbit in the optimal solution,and orientation of axis depends on the latitude argument where a collision will occur.The dangerous area is represented especially with the graphical dialogue,and it allows to find a compromise between the SO avoiding and the fuel consumption reduction.The proposed method to solve the collision avoidance problem provides simplicity to calculate rendezvous maneuvers,and possibility to avoid collisions from several collisions or from“slow”collisions in a phasing orbit,when the protected spacecraft and the object fly dangerously close to each other for a long period.
