A modified method of discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces

This paper presents an automated method for discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces.Specifically,the method consists of five steps:(1)detection of trace feature points by normal tensor voting theory,(2)co ntraction of trace feature points,(3)connection of trace feature points,(4)linearization of trace segments,and(5)connection of trace segments.A sensitivity analysis was then conducted to identify the optimal parameters of the proposed method.Three field cases,a natural rock mass outcrop and two excavated rock tunnel surfaces,were analyzed using the proposed method to evaluate its validity and efficiency.The results show that the proposed method is more efficient and accurate than the traditional trace mapping method,and the efficiency enhancement is more robust as the number of feature points increases.

Three-dimensional computed tomography mapping of posterior malleolar fractures

BACKGROUND Posterior malleolar fractures have been reported to occur in<40%of ankle fractures.AIM To reveal the recurrent patterns and characteristics of posterior malleolar fractures by creating fracture maps of the posterior malleolar fractures through the use of computed tomography mapping.METHODS A consecutive series of posterior malleolar fractures was used to create threedimensional reconstruction images,which were oriented and superimposed to fit an ankle model template by both aligning specific biolandmarks and reducing reconstructed fracture fragments.Fracture lines were found and traced in order to generate an ankle fracture map.RESULTS This study involved 112 patients with a mean age of 49,comprising 32 pronationexternal rotation grade IV fractures and 80 supination-external rotation grade IV fractures according to the Lauge-Hansen classification system.Three-dimensional maps showed that the posterior ankle fracture fragments in the supinationexternal rotation grade IV group were relatively smaller than those in the pronation-external rotation grade IV group after posterior malleolus fracture.In addition,the distribution analyses on posterior malleolus fracture lines indicated that the supination-external rotation grade IV group tended to have higher linear density but more concentrated and orderly distribution fractures compared to the pronation-external rotation grade IV group.CONCLUSION Fracture maps revealed the fracture characteristics and recurrent patterns of posterior malleolar fractures,which might help to improve the understanding of ankle fracture as well as increase opportunities for follow-up research and aid clinical decision-making.

Application of Three-dimensional Laser Scanning Technology in the Teaching Practice of Surveying and Mapping of Ancient Buildings

Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser scanning technology.Based on the practical application,this paper puts forward the discussion of related problems and matters needing attention.This has a certain reference significance for the study of new technology in surveying and mapping of ancient buildings.

Active Micro-Nano-Collaborative Bioelectronic Device for Advanced Electrophysiological Recording

The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic devices have undergone significant advancements,thereby facilitating the study of electrophysiology.The distinctive configuration and exceptional functionality of these active micro-nano-collaborative bioelectronic devices offer the potential for the recording of high-fidelity action potential signals on a large scale.In this paper,we review three-dimensional active nano-transistors and planar active micro-transistors in terms of their applications in electroexcitable cells,focusing on the evaluation of the effects of active micro/nano-bioelectronic devices on electrophysiological signals.Looking forward to the possibilities,challenges,and wide prospects of active micro-nano-devices,we expect to advance their progress to satisfy the demands of theoretical investigations and medical implementations within the domains of cardiology and neuroscience research.

Asymmetric image encryption algorithm based on a new three-dimensional improved logistic chaotic map

Based on some analyses of existing chaotic image encryption frameworks and a new designed three-dimensional improved logistic chaotic map(3D-ILM),an asymmetric image encryption algorithm using public-key Rivest–Shamir–Adleman(RSA)is presented in this paper.In the first stage,a new 3D-ILM is proposed to enhance the chaotic behavior considering analysis of time sequence,Lyapunov exponent,and Shannon entropy.In the second stage,combined with the public key RSA algorithm,a new key acquisition mathematical model(MKA)is constructed to obtain the initial keys for the 3D-ILM.Consequently,the key stream can be produced depending on the plain image for a higher security.Moreover,a novel process model(NPM)for the input of the 3D-ILM is built,which is built to improve the distribution uniformity of the chaotic sequence.In the third stage,to encrypt the plain image,a pre-process by exclusive OR(XOR)operation with a random matrix is applied.Then,the pre-processed image is performed by a permutation for rows,a downward modulo function for adjacent pixels,a permutation for columns,a forward direction XOR addition-modulo diffusion,and a backward direction XOR addition-modulo diffusion to achieve the final cipher image.Moreover,experiments show that the the proposed algorithm has a better performance.Especially,the number of pixels change rate(NPCR)is close to ideal case 99.6094%,with the unified average changing intensity(UACI)close to 33.4634%,and the information entropy(IE)close to 8.

Balanced Functional Maps for Three-Dimensional Non-Rigid Shape Registration

Three-dimensional(3D)shape registration is a challenging problem,especially for shapes under non-rigid transformations.In this paper,a 3D non-rigid shape registration method is proposed,called balanced functional maps(BFM).The BFM algorithm generalizes the point-based correspondence to functions.By choosing the Laplace-Beltrami eigenfunctions as the function basis,the transformations between shapes can be represented by the functional map(FM)matrix.In addition,many constraints on shape registration,such as the feature descriptor,keypoint,and salient region correspondence,can be formulated linearly using the matrix.By bi-directionally searching for the nearest neighbors of points’indicator functions in the function space,the point-based correspondence can be derived from FMs.We conducted several experiments on the Topology and Orchestration Specification for Cloud Applications(TOSCA)dataset and the Shape Completion and Animation of People(SCAPE)dataset.Experimental results show that the proposed BFM algorithm is effective and has superior performance than the state-of-the-art methods on both datasets.

Design and Realization of Block Level Augmented Reality Three-Dimensional Map

In response to the construction needs of “Real 3D China”, the system structure, functional framework, application direction and product form of block level augmented reality three-dimensional map is designed. Those provide references and ideas for the later large-scale production of augmented reality three-dimensional map. The augmented reality three-dimensional map is produced based on skyline software. Including the map browsing, measurement and analysis and so on, the basic function of three-dimensional map is realized. The special functional module including housing management, pipeline management and so on is developed combining the need of residential quarters development, that expands the application fields of augmented reality three-dimensional map. Those lay the groundwork for the application of augmented reality three-dimensional map. .

Science Letters:Dynamic concision for three-dimensional reconstruction of human organ built with virtual reality modelling language (VRML)

This research studies the process of 3D reconstruction and dynamic concision based on 2D medical digital images using virtual reality modelling language (VRML) and JavaScript language, with a focus on how to realize the dynamic concision of 3D medical model with script node and sensor node in VRML. The 3D reconstruction and concision of body internal organs can be built with such high quality that they are better than those obtained from the traditional methods. With the function of dynamic concision, the VRML browser can offer better windows for man-computer interaction in real-time environment than ever before. 3D reconstruction and dynamic concision with VRML can be used to meet the requirement for the medical observation of 3D reconstruction and have a promising prospect in the fields of medical imaging.

Initial experience with circumferential pulmonary vein ablation guided by fusion of magnetic resonance imaging with three-dimensional electroanatomic mapping

Catheter ablation for the treatment of atrial fibrillation （AF） has been a focal target ofelectrophysiological study in recent years. Up to date, circumferential pulmonary vein ablation （CPVA） guided by three-dimensional （3-D） electreanatomic mapping （Carto, USA） has been one of the most favourable procedures for the treatment of AF. However, it is still difficult to acquire the detailed information on number, location, and branching pattern of all pulmonary veins （PVs） when the 3-D electroanatomic mapping system is used alone.

A novel mapping algorithm for three-dimensional network on chip based on quantum-behaved particle swarm optimization

Mapping of three-dimensional network on chip is a key problem in the research of three-dimensional network on chip. The quality of the mapping algorithm used di- rectly affects the communication efficiency between IP cores and plays an important role in the optimization of power consumption and throughput of the whole chip. In this paper, ba- sic concepts and related work of three-dimensional network on chip are introduced. Quantum-behaved particle swarm op- timization algorithm is applied to the mapping problem of three-dimensional network on chip for the first time. Sim- ulation results show that the mapping algorithm based on quantum-behaved particle swarm algorithm has faster con- vergence speed with much better optimization performance compared with the mapping algorithm based on particle swarm algorithm. It also can effectively reduce the power consumption of mapping of three-dimensional network on chip.

Three-dimensional Dominant Frequency Mapping Using Autoregressive Spectral Analysis of Atrial Electrograms of Patients in Persistent Atrial Fibrillation

Areas with high frequency activity within the atrium are thought to be 'drivers' of the rhythm in patients with atrial fibrillation (AF) and ablation of these areas seems to be an effective therapy in e-liminating DF gradient and restoring sinus rhythm. Clinical groups have applied the traditional FFT-based approach to generate the three-dimensional dominant frequency (3D DF) maps during electro-physiology (EP) procedures but literature is restricted on using alternative spectral estimation tech-niques that can have a better frequency resolution that FFT-based spectral estimation.

Multispectral image compression and encryption method based on tensor decomposition in wavelet domain

Multispectral image compression and encryption algorithms commonly suffer from issues such as low compression efficiency,lack of synchronization between the compression and encryption proces-ses,and degradation of intrinsic image structure.A novel approach is proposed to address these is-sues.Firstly,a chaotic sequence is generated using the Lorenz three-dimensional chaotic mapping to initiate the encryption process,which is XORed with each spectral band of the multispectral image to complete the initial encryption of the image.Then,a two-dimensional lifting 9/7 wavelet transform is applied to the processed image.Next,a key-sensitive Arnold scrambling technique is employed on the resulting low-frequency image.It effectively eliminates spatial redundancy in the multispectral image while enhancing the encryption process.To optimize the compression and encryption processes further,fast Tucker decomposition is applied to the wavelet sub-band tensor.It effectively removes both spectral redundancy and residual spatial redundancy in the multispectral image.Finally,the core tensor and pattern matrix obtained from the decomposition are subjected to entropy encoding,and real-time chaotic encryption is implemented during the encoding process,effectively integrating compression and encryption.The results show that the proposed algorithm is suitable for occasions with high requirements for compression and encryption,and it provides valuable insights for the de-velopment of compression and encryption in multispectral field.

Carto XP/Carto3与常规标测指导下消融特发性右室流出道室性早搏的比较

目的比较常规电生理标测与三维电解剖标测系统(Carto XP/Carto3)标测指导下行导管射频消融治疗特发性右室流出道室性早搏(right ventricular outflow tract premature ventricular contraction,RVOT-PVC)的有效性和安全性。方法分析2013年3月至2015年10月于我科进行射频消融治疗的144例室早病例:36例室早患者采用常规电生理标测指导下射频消融(常规组),108例室早采用Carto XP/Carto3标测指导下射频消融(Carto XP/Carto3组)。从靶点标测、消融、术中X线曝光以及手术总耗时等时间方面对两种标测方法进行比较;检测两组术前及术后1 d和3 d C反应蛋白(C reactive protein,CRP)、血清肌钙蛋白Ⅰ(serum cardiac troponinⅠ,c TnⅠ)和磷酸肌酸激酶同工酶(creatine kinase-MB,CK-MB)的变化,观察随访疗效。结果 Carto XP/Carto3组在室早靶点标测、成功消融、X线曝光以及手术总时间方面均较常规电生理标测组明显缩短(P<0.01),心肌损伤指标CRP、c TnⅠ和CK-MB均明显降低(P<0.01);两组的即刻成功率分别为94.4%(34/36)和100%(108/108),差异有统计学意义;术后1个月随访时,常规组即刻成功的34例患者中有3例室早复发,Carto XP/Carto3组无复发病例。术后3个月时,两组均无新的复发病例。结论 Carto XP/Carto3标测指导的消融靶点定位更精准,手术安全性及有效性更好;常规电生理标测指导的射频消融仍具有较高成功率,手术费用相对便宜,为经济困难而又确实需要消融治疗的患者提供了一种可行的选择方案。

应用三维磁导航系统标测和消融快速性心律失常的初步经验

目的观察三维磁导航系统标测和消融快速性心律失常的疗效。方法结合NiobeII磁导航系统和CARTO-RMT电解剖标测系统,采用4mm-顶端的NaviStar-RMT标测和消融导管进行射频消融治疗快速性心律失常。结果10例患者,男6例,女4例。房室结折返性心动过速4例,其中1例合并阵发性心房颤动,左侧房室旁道2例,右侧房室旁道1例,典型心房扑动2例,右室流出道室性心动过速1例。磁导航系统遥控操作,10例均完成电生理标测。9例消融成功,失败1例为心房扑动患者,换用NaviStar盐水灌注导管后消融成功。导管操作时间93±33.1min,X线曝光时间12.5±6.5min。随访6个月无复发。结论对于快速性心律失常,应用磁导航系统可进行有效和安全的三维标测和消融。

梳状电极多导联同步记录标测犬Marshall韧带——一种新技术

评价经心外膜标测Marshall韧带的新方法及其意义。对 1 9只犬经心外膜途径对Marshall韧带进行标测 ,采用梳状电极平行贴靠于Marshall韧带和平行贴靠于冠状静脉窦标测Marshall韧带 ,均同步记录 1 0道双极心外膜电图。对可记录到Marshall韧带电位的犬在Marshall韧带冠状静脉窦入口处及其中段与左心房连接处注射无水酒精消融至Marshall韧带电位消失。①Marshall韧带电位记录率为 89.5 % (1 7/ 1 9)。②平行贴靠于Marshall韧带时双极心外膜电图特征 :心房波从上至下逐渐拖后 ,其与逐渐提前的Marshall韧带电位相交形成典型“V”字形 ,或中段与近端记录的Mar shall韧带电位均提前并与心房波相交形成不典型“V”字形 (类似“Y”字形 )。呈典型“V”字形者 1 0只占 58.8% (1 0 / 1 7) ,对其中的 9只犬进行酒精消融 ,在Marshall韧带冠状静脉窦入口处酒精消融导致Marshall韧带电位全部消失 ;不典型“V”字形者 (类似“Y”字形 )者占 7只 ,占 41 .2 % (7/ 1 7) ,对其中 2只犬进行了酒精消融 ,除消融Marshall韧带冠状静脉窦入口外还需在其中段与左心房的连接点处消融才能导致电位完全消失。③梳状电极平行贴靠于冠状静脉窦并且横跨Marshall韧带记录 ,Marshall韧带冠状静脉窦入口处可记录到Marshall韧带电位。梳状电?

心脏病外科术后右房房性心动过速的标测及射频消融

目的总结分析心脏病外科术后右房起源房性心动过速(简称房速)的标测及射频消融结果。方法共入选27例心脏外科术后持续性右房房速患者,在心动过速状态下采用三维电解剖标测系统建立右房激动标测图和电压图,标示出疤痕区及双电位区,并揭示心动过速的机制。根据标测结果选择心动过速的关键峡部或起源点进行消融。结果心动过速机制分为以下几种类型:单环折返包括右房峡部依赖性心房扑动(15例)和切口折返性房速(5例);双环折返性房速(3例);两种以上机制(包括局灶性)的复杂房速(4例)。术中即时手术成功率100%。随访过程中5例复发房速,3例再次消融成功。结论心脏外科术后右房房速多数与外科手术切口疤痕相关,在三维电解剖标测系统指导下射频消融治疗效果满意。

Carto系统指导下左房电解剖隔离治疗心房颤动

对 3例阵发性和 2例持续性心房颤动 (简称房颤 )进行左房线性消融。采用Carto标测构建左房三维电解剖图 ,并标识出肺静脉和二尖瓣环 ,在距肺静脉口外 1～ 2cm处进行绕左右肺静脉和左房峡部的环状线性隔离消融 ,后 2例增加一条左房后壁的消融线 ,消融的终点为 :①环状隔离区内的双极电压≤ 0 .1mV ,②跨消融线相邻两点的传导时间延迟 30ms以上。结果 :整个手术时间为 2 2 9± 18min ,X线曝光时间为 2 5± 3min。消融线环绕的左房面积占整个被标测左房面积的 36 %± 3.2 % ,消融线环绕的左房区域内的电压较消融前明显降低 ,绕消融线以外的部分心房组织的电压亦降低。 3例阵发性房颤有 2例在术后 1～ 2天有房颤发作 ,1例持续性房颤于术后 1周转为持续性心房扑动 ,3周时电复律为窦性心律 ,术中和术后随访期内无并发症发生 ,5例在 5 .3± 1.85个月的随访中无有症状的房颤发作。结论 :左房线性电隔离治疗房颤是安全有效的方法。

慢性心力衰竭致心室颤动诱颤阈值变化的电生理机制研究

目的研究慢性心力衰竭(简称心衰)易于促发心室颤动(简称室颤)可能的电生理机制。方法 12只比格犬随机分为对照组(n=6)和心衰组(n=6)。通过右室心尖部快速起搏4周制作犬充血性心衰模型。经左侧颈内动脉将64极伞状电极置于左室进行整体心内膜电生理标测。采用S1S2刺激方案测定心室有效不应期(ERP);通过连续S1S1刺激法诱发室颤;测定不同起搏周期最后一次起搏心律时每个电极的激动恢复间期并计算64个电极之间的变异系数。同时,比较两组心脏在300 ms起搏时的整体左室心内膜激动传导时间和分布。结果与对照组相比,心衰组左室ERP显著延长(180±6.7 ms vs 158±6.9 ms,P<0.01);在300,250,200和150 ms周期起搏时的左室激动恢复间期显著延长。两组不应期离散度在300 ms和250 ms起搏时无显著差异,但在200 ms和150 ms起搏时,心衰组不应期离散度显著增大。心衰组左室心内膜传导较对照组延迟达17.9%(41.2±0.7 ms vs 34.9±1.6 ms,P<0.01)。与对照组相比,心衰组更易诱发室颤(127±17 ms vs 103±8 ms,P<0.01)。结论心室复极延长、传导速度减慢以及不应期离散度增大可能是慢性心衰者易于促发室颤的原因。

EnSite NavX三维电生理系统指导下环肺静脉前庭隔离导管消融治疗心房颤动

目的探讨EnSite NavX三维电生理系统指导环肺静脉前庭隔离导管消融治疗心房颤动(房颤)的有效性和安全性。方法在EnSite NavX三维电生理系统指导下对38例药物治疗无效的阵发性或持续性房颤患者行环肺静脉导管消融,随访观察其疗效和安全性。结果38例患者都达到消融终点,双侧肺静脉均完全隔离。手术操作时间(233.8±31.7)min,X线曝光时间(32.5±4.7)min,左房建模时间(27.5±7.5)min。术后随访(9±3)月,单次消融的成功率为89.5%,出现并发症7.9%。结论EnSite NavX三维电生理系统指导下环肺静脉前庭隔离导管消融治疗房颤是一种较为有效且安全的方法。

CARTO标测指导射频消融治疗不适当的窦性心动过速

一例 34岁女性患者心悸、胸闷 2年半。Holter示最大心率 176次 /分 ,平均心率 12 7次 /分 ,固有心率 12 6次 /分。在基础窦性心律、静脉滴注 (简称静滴 )异丙肾上腺素后及射频消融术后分别行CARTO标测。静滴异丙肾上腺素后 ,心率从 14 5次 /分增至 170次 /分 ,最早激动点沿界嵴向上移动 3mm。消融靶点 (静滴异丙肾上腺素后的最早心房激动点 )由CARTO标测定位。在释放 2 1次射频电流进行射频消融后 ,未静滴异丙肾上腺素的心率从术前的14 5次 /分降至 98次 /分 ,静滴异丙肾上腺素后的心率从术前的 170次 /分降至 14 0次 /分。Ⅱ、Ⅲ、aVF导联上的P波形态从明显直立变为低平。术后第 3天Holter示最大心率和平均心率分别为 12 5次 /分和 95次 /分 ;固有心率为94次 /分。结论 :CARTO标测有助于精确地定位不适当的窦性心动过速的消融靶点 ,减少射频消融的放电次数 ,提高成功率。