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.

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. .

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.

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.

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.

Role of three-dimensional imaging integration in atrial fibrillation ablation

Atrial fibrillation is the most common arrhythmia and in symptomatic patients with a drug-refractory form,catheter ablation aimed at electrically disconnecting the pulmonary veins(PVs) has proved more effective than use of antiarrhythmic drugs in maintaining sinus rhythm during follow-up.On the other hand,this ablation procedure is complex,requires specific training and adequate clinical experience.A main challenge is represented by the need for accurate sequential positioning of the ablation catheter around each veno-atrial junction to deliver point-by-point radiofrequency energy applications in order to achieve complete and persistent electrical disconnection of the PVs.Imaging integration is a new technology that enables guidance during this procedure by showing a three-dimensional,pre-acquired computed tomography or magnetic resonance image and the relative real-time position of the ablation catheter on the screen of the electroanatomic system.Reports in the literature suggest that imaging integration provides accurate visual information with improvement in the procedure parameters and/or clinical outcomes of the procedure.

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.

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.

Linear ablation of left atrium for the treatment of atrial fibrillation guided by double Lasso catheters and three dimensional electroanatomical mapping

Background Linear ablation of left atrium （LA） guided by three dimensional （3-D） electroanatomical mapping （Carto） has been used in many centres worldwide for the treatment of atrial fibrillation （AF） instead of pure anatomical approaches. There were little data about linear ablation of LA guided by Carto and double Lasso catheters in China. We report the results of linear ablation of LA guided by both Carto and double Lasso catheters. Methods After the anatomical model of LA and all pulmonary veins （PVs） had been established, circumferential ablations of the left pulmonary vein antrum and the right pulmonary vein antrum were performed with 2 circumferential mapping catheters （Lasso） placed within the ipsilateral superior and inferior PVs. The endpoint of ablation was abolishment or dissociation of the pulmonary vein potentials （PVPs）. Oral amiodarone or propafenone was taken for at least 3 months by patients with persistent AF, permanent AF or those whose PVPs had not been isolated completely. The recurrence of atrial tachyarrhythmias was observed 3 months after the procedure. Results There were 106 patients （mean age, 51.4±9.9 years）. Seventy-eight patients had paroxysmal AF, 12 persistent AF and 16 permanent AF. Onset of atrial fibrillation occurred in 52 patients during ablation procedure. Thirty-two patients restored to sinus rhythm eventually after the procedure. Abolishment or dissociation of PVPs was accomplished during the procedure in 94 patients （88.7%）. The duration of procedure and exposure to X-ray were （213±45） minutes and （32.5± 12.8） minutes, respectively. Among the 87 patients followed up for over 3 months, 62 were free of atrial tachyarrhythmias （including 8 patients who were still taking oral amiodarone）. The success rate was 71.3% in the first procedure. Two patients had pericardial effusion treated by pericardial puncture and effusion drainage. No pulmonary vein stenosis, atrioesophageal fistula, stroke or procedural death occurred. Conclusions Combination of double Lasso catheters with 3-D electroanatomical mapping to guide the linear ablation of left atrium procedure can confirm the isolation of PVPs.

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.

百年心电绽芳华:心电图临床应用进展及展望

心电图应用于临床已有120年历史,至今仍是临床最重要的常规检查之一。远程心电、便携心电和云心电平台的加速普及给心电插上了翅膀,把心电技术从医院推向社会、家庭乃至每一个人。体表三维电解剖标测的问世使抽象的心电图形得以可视化呈现,能清楚揭示心律失常的起源和心电信号的传导过程,相当于为心电图做了“病理解剖”般的金标准验证诊断。人工智能心电通过深度学习更能挖掘出既往心电所不能解读的领域,大大拓展了心电的内涵。本文简要回顾了120年来心电图技术从远程心电、三维心电、便携心电直到人工智能心电的发展历程,并展望了未来心电图技术的发展趋势。

国产三维心脏电生理标测系统用于左侧房室旁路射频消融的前瞻性、随机对照研究:经股动脉逆行法与经房间隔穿刺法比较

目的探究左侧房室旁路消融经股动脉逆行法与经房间隔穿刺法的优劣及评价国产三维心脏电生理标测系统的性能。方法采用前瞻性、随机对照研究设计,自2019年7月至2020年8月入选室上性心动过速患者30例,术前行心电生理检查确定为左侧房室旁路并具有导管射频消融适应证,以1∶1的比例将患者随机分配至经股动脉逆行组和经房间隔穿刺组。在国产三维心脏电生理标测系统(Columbus■系统)指导下行左侧房室旁路射频消融术,比较两组患者的靶点标测成功率、术后即刻消融成功率、X线曝光时间、X线辐射剂量、手术时间、术中及术后不良事件的发生率。结果两组的靶点标测成功率和术后即刻消融成功率均为100%。经房间隔穿刺组的手术时间[(75.40±22.27)min]、X线曝光时间[384(310,510)s]和X线辐射剂量[93(63,123)mGy]与经股动脉逆行组的[(83.80±39.96)min、369(340,989)s和154(56,184)mGy]相比差异均无统计学意义(P均>0.05)。经股动脉逆行组术后不良事件发生率为6.7%(1/15),经房间隔穿刺组无不良事件发生,两组术后不良事件发生率差异无统计学意义(P>0.05)。国产三维心脏电生理标测系统可清晰显影导管电极,导管操作性能良好,能够顺利定位,贴靠满意。结论国产三维心脏电生理标测系统可安全、有效地用于左侧房室旁路的射频消融,经房间隔穿刺法和经股动脉逆行法2种消融策略在手术时间、X线曝光时间与剂量、不良事件发生率等方面没有区别。

左心房心房扑动射频消融治疗进展

心房扑动(房扑)是一种大折返性心律失常,与心房颤动关系密切,二者经常共存。导管消融术已成为房扑的一线治疗措施,但随访发现患者消融术后新发房性心律失常比例仍然较高。左心房房扑与典型右心房房扑相比机制更为复杂,常与各种原因导致的左心房纤维化有关,且左心房周围毗邻结构也较复杂,对安全有效地消融造成一定困难。随着高精密度标测系统和消融能量的发展,左心房房扑机制越来越清晰,这为左心房房扑实施有效透壁消融终止房扑提供了依据。

心脏三维电解剖标测在导管射频消融术治疗阵发性室上性心动过速患者中的应用

目的探讨心脏三维电解剖标测在导管射频消融术治疗阵发性室上性心动过速患者中的应用。方法选取2018年10月至2020年4月中国人民解放军联勤保障部队第九〇四医院诊治的阵发性室上性心动过速患者87例,根据治疗方法不同分为对照组41例和观察组46例。对照组在X线透视下完成导管射频消融术治疗,观察组在心脏三维电解剖标测系统下完成导管射频消融术治疗,术后完成6个月随访。比较两组消融成功率、手术时间、X线辐射量、并发症及复发率;对患者复发情况进行单因素分析及多因素Logistic分析。结果两组术后1、3个月复发率无统计学意义(P>0.05);观察组术后并发症发生率及术后6个月复发率均低于对照组(χ^(2)=5.002、5.002,P<0.05);观察组X线辐射剂量和辐射时间低于对照组(t=10.936、11.322,P<0.05)。87例患者6个月随访时未有患者死亡,将复发2例作为复发组,其余作为未复发组,进行单因素分析,结果显示两组手术方法差异有统计学意义(χ^(2)=7.297,P<0.05)。多因素Logistic回归分析结果显示,手术方式是患者复发的影响因素[OR(95%CI)=1.846(1.527~2.313),P<0.05]。结论在阵发性室上性心动过速患者导管射频消融术治疗中应用心脏三维电解剖标测能减少辐射剂量,术后并发症和复发率较低。

Review of Ex Vivo Cardiac Electrical Mapping and Intelligent Labeling of Atrial Fibrillation Substrates

With the development of computer hardware and the growth of clinical database,tremendous progress has been made in the application of deep learning to electrocardiographic data,which provides new ideas for the ex vivo cardiac electrical mapping of atrial fibrillation(AF)substrates.The AF mechanism and current status of AF substrate research are first summarized.Then,the advantages and limitations of cardiac electrophysiological mapping techniques are analyzed.Finally,the application of deep learning to electrocardiogram(ECG)data is reviewed,the problems with the ex vivo intelligent labeling of an AF substrate and the possible solutions are discussed,an outlook on future development is provided.

不同节律下心房颤动患者心房低电压区比较及意义

目的探讨不同节律下心房颤动(简称房颤)患者电解剖标测心房低电压区(low voltage areas,LVAs)的特征及意义,并分析单纯肺静脉隔离(pulmonary vein isolation,PVI)术对LVAs的影响。方法连续纳入首次接受射频消融治疗的84例房颤患者,其中49例阵发性房颤,35例持续性房颤,使用倾向性评分进行匹配。在0.5 mV的阈值下测量心房五分区后各区域LVAs的面积并进行分析。结果根据年龄、性别、BMI,采用倾向性评分匹配出31组患者。阵发性房颤患者术前平均标测点数为(1434.2±393.6)个,术后为(1281.3±372.7)个;持续性房颤患者术前平均标测点数为(1652.6±728.2)个,术后为(1314.6±690.8)个。在所有研究对象中,均可记录到LVAs的存在。阵发性房颤患者术前术后LVAs面积比较,差异无统计学意义;持续性房颤患者LVAs面积术后明显下降(P<0.05)。在所有84例房颤患者中,LVAs出现在前壁、间隔、下壁、侧壁和后壁的比例分别为69.0%、95.2%、82.1%、60.7%和52.4%。结论在相同的电压阈值下,持续性房颤患者LVAs面积在房颤节律下明显大于窦性节律下,单纯PVI术对LVAs影响不大。房颤患者中LVAs好发于前壁、间隔及下壁。

三维标测系统Carto指导下消融特发性室性心动过速

目的:评价Carto三维标测系统在标测、消融特发性室性心动过速(VT)中的应用价值。方法:15例特发性VT患者,程序刺激诱发VT后,采用Carto指导下激动顺序标测和(或)起搏标测,冷盐水灌注导管进行消融。观察消融即刻成功率、手术时间、消融时间和X线曝光时间以及并发症情况。通过随访评价导管消融后的远期疗效。结果:15例患者均完成Carto指导下电解剖重建,11例为特发性流出道VT,4例为左室特发性VT。消融放电(4.2±1.1)次VT终止,累计放电时间(205.0±13.4)s;手术时间(3.50±0.85)h,X线曝光时间(15.0±7.9)min。所有患者术中即刻均达到消融终点,平均随访6个月,无VT复发。结论:Carto指导下标测、消融能有效治疗特发性VT,同时消融手术时间缩短,远期疗效好。