WSN Mobile Target Tracking Based on Improved Snake-Extended Kalman Filtering Algorithm

A wireless sensor network mobile target tracking algorithm(ISO-EKF)based on improved snake optimization algorithm(ISO)is proposed to address the difficulty of estimating initial values when using extended Kalman filtering to solve the state of nonlinear mobile target tracking.First,the steps of extended Kalman filtering(EKF)are introduced.Second,the ISO is used to adjust the parameters of the EKF in real time to adapt to the current motion state of the mobile target.Finally,the effectiveness of the algorithm is demonstrated through filtering and tracking using the constant velocity circular motion model(CM).Under the specified conditions,the position and velocity mean square error curves are compared among the snake optimizer(SO)-EKF algorithm,EKF algorithm,and the proposed algorithm.The comparison shows that the proposed algorithm reduces the root mean square error of position by 52%and 41%compared to the SOEKF algorithm and EKF algorithm,respectively.

适用于多目标图像分割的改进BVF Snake模型

参数活动轮廓模型(Snake)在计算机视觉和图像处理领域有着广泛的应用。传统的Snake算法存在许多不足,包括计算量大和当存在多目标时不能收敛到特定目标。虽然边界向量场(Boundary Vector Field, BVF) Snake减小了计算量强度,但是当存在多目标时仍然不能收敛到特定目标。本文通过力场分析,确定了BVF Snake不适用于多目标图像分割的原因;通过改进,提出一种改进的方向BVF (directional BVF, DBVF) Snake模型;在该模型中,通过在特定目标内部增加一个点,得到一个方向向量场,来确定Snake的收敛方向,使其在存在多目标时可以收敛到特定目标。本文对DBVF Snake在增大捕捉范围、添加不同噪声两个方面和常见的Snake模型进行了对比分析,同时对声呐图像进行了分割,实验结果证明了本文提出的模型(方法)对多目标图像分割的有效性。

一种改进的Ribbon Snake遥感图像道路自动生成算法

针对树木或高大建筑物遮挡以及噪声等因素造成道路提取结果不完整的现象,根据道路的几何特征,在Snake模型中加入道路宽度信息,构造Ribbon Snake模型。为了克服模型对内部参数依赖性较大、容易受到复杂背景干扰影响的不足,采用B样条曲线对道路的平滑性进行约束,与Ribbon Snake相结合建立道路提取算法,通过调节控制点的数目增强曲线的灵活性。从改进的B样条Ribbon Snake的道路网分割结果可以看出,分割的结果更加平滑,精度更高,对噪声具有更好的鲁棒性。

基于snake算法的声呐图像轮廓提取方法

针对成像声呐的水下目标检测问题,提出一种改进的snake目标轮廓提取方法。该方法首先通过构建高斯模型对成像声呐进行目标检测,提高了目标检测能力。其次根据预设目标粗略区域,结合梯度矢量流(GVF)改进的snake算法,实现了目标轮廓的连续提取。仿真试验验证了所提方法的有效性。

Finite-Time Sideslip Differentiator-Based LOS Guidance for Robust Path Following of Snake Robots

This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.

基于Snake-Net算法的刺绣针法识别

为有效提取刺绣图像中针法的特征值,实现刺绣针法的分类识别,在分析刺绣针法特点的基础上,提出了点状针法、线状针法和块面状针法的三大针法分类,并以占主体的块面状针法中的齐针、抢针和套针3种基础针法为处理对象,分析对比其针法特征,构建针法模型。针对刺绣针法图像进行图像纹理细节的增强处理,基于Harris角点检测特征点和Canny轮廓筛选,对传统Snake算法进行改进,形成智能化HC-Snake模型,实现对目标轮廓的智能化识别并提取目标图像的纹理及颜色特征。通过数据的方差分析确定CON sd,IDM sd,E a,E sd,ENT a,ENT sd,COR sd,SM和TM共9个特征指标,建立特征数据集。最后,建立神经网络分类模型,对针法样本进行分类,并对识别模型进行了实例验证。结果表明,该模型可以实现刺绣针法图像的分类,且分类准确率达到93.3%。

Position Errors and Interference Prediction-Based Trajectory Tracking for Snake Robots

This work presents a trajectory tracking control method for snake robots.This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined trajectory.The optimized line-of-sight(LOS)guidance strategy drives the robot’s steering angle to maintain its anti-sideslip ability by predicting position errors and interferences.Then,the predictions of system parameters and viscous friction coefficients can compensate for the joint torque control input.The compensation is adopted to enhance the compatibility of a robot within ever-changing environments.Simulation and experimental outcomes show that our work can decrease the fluctuation peak of the tracking errors,reduce adjustment time,and improve accuracy.

The peptide fraction of Bothrops jararaca snake venom induces toxicological effects on the male reproductive system after local envenomation in mice

Bothrops envenomation is complex and provokes prominent local tissue damage and systemic disturbances,but little is known about their effects on the male reproductive system.After intratesticular injection,the bioactive peptide fraction(Bj-PF)obtained from Bothrops jararaca snake venom changes the structure of different stages of the seminiferous epithelium cycle in adult mice.For the first time,we investigated whether local envenomation of Bj-PF induces toxicological effects on the male reproductive system,particularly on the seminiferous epithelium and Sertoli cells.Male adult mice were treated with 0.24 mg.kg^(-1) by intramuscular(i.m.)injection for 24 h.The testes samples were collected for morphological and morphometric evaluation.The toxicological effects of Bj-PF were also analyzed on mitochondrial metabolism and nitrite(NO2)production in 15P-1 Sertoli cell culture.Bj-PF changed the structure and function of the seminiferous epithelium,particularly the disruption of the epithelium and the presence of degenerated germ cells in the adluminal compartment,but there were no alterations in the basal compartment.Bj-PF increased the thickness of the seminiferous epithelium and decreased the lumen diameter of the tubule.Semiquantitative histological assessment of the degree of tubule degeneration revealed that Bj-PF also increased the number of hypospermatogenic tubules compared to control.Bj-PF reduced NO2 levels in 15P-1 Sertoli cells without changing the mitochondrial metabolism.Overall,the fact that Bj-PF alters the structure and function of the seminiferous epithelium suggests that bioactive peptides found in B.jararaca snake venom can have toxicological effects on the reproductive systems of affected male mice,providing new insight into the biological characteristics of snake venom and therapeutic strategies for envenomation inflammation.

Isolation and identification of four pathogenic bacterial strains from edible snake(Elaphe carinata and Ptyas mucosus)farms with pneumonia in China

This report describes an outbreak and treatment of pneumonia and enteritis in a snake farm with more than 3000 snakes containing Elaphe carinata(one-year-old)and Ptyas mucosus(three-month-old)seedlings in Huanggang,Hubei,China.Gentamicin was used once in the early stage as treatment,administered orally with water or feed by owners,but mortality increased.Lobar pneumonia was confirmed by dissection and histopathology in infected snakes.Four main pathogenic bacteria were isolated and identified with culture and 16S rRNA sequencing:Staphylococcus sciuri,Salmonella enteritis,Vagococcus fluvialis and Providencia vermicola.Drug susceptibility tests were performed,and amikacin,gentamicin and cefitriaxone were chosen accordingly.After two rounds of treatment,the clinical signs for Elaphe carinata were under control,and the mortality was close to 0%after treatment.However,treatments for Ptyas mucosus seedlings did not work well,potentially because of poor administration technique and weak body condition.

Placental Abruption Following Snakebites Envenomation: A Case Report and Literature Review

Background: Snakebite envenomation in pregnancy is uncommon. It can lead to a poor outcome in both the mother and the fetus. We describe our approach to envenomation in pregnancy based on the currently available evidence. Case: We reported two case of snakebite in the third trimester of pregnancy having caused placental abruption with expelling a fresh still born baby and a live baby. In both cases, consumption coagulopathy occurred. managed by polyvalent anti-snake and blood transfusion. Their investigations became normal and they were discharged of hospitalization. Conclusion: Snakebite envenomation in pregnant is a maternal and fetal emergency. Treatment must be quick and well adapted.

Review on Preparation and Research of Prescriptions for Snake Bites in Fujian Province

The history of research and preparation of prescriptions for snake bites in Fujian Province was reviewed, and the process of incorporating snake doctors into the system and the gradual establishment of snake bite treatment system in Fujian were explored. The composition of several main snake bite preparations in Fujian was preliminarily compared and analyzed to provide reference for the research and development of similar new preparations at present.

Snake模型的研究进展

为进一步理解Snake模型,首先以归类方式系统地总结了Snake模型的各种改进模型及其最新应用状况;在此基础上,讨论了Snake模型的研究难点和发展趋势。分析结果表明,虽然Snake各种改进模型和基本Snake模型有较大的差异,但其研究思想一脉相承。此外,可针对各种改进模型的优缺点将其应用到不同场景中。

一种新的FAST-Snake目标跟踪方法

提出一种新的FAST-Snake目标跟踪方法,利用改进的FAST角点特征匹配来估计目标轮廓在帧间的全局仿射变换,将投影轮廓点作为Snake模型的初始化轮廓.为提高跟踪实时性,在Snake能量模型中定义了先验约束能,并用限定搜索方向的贪婪算法(Greedy algorithm)实现局部轮廓优化.实验包括三维目标数据库及真实场景视频,验证了提出方法的均方误差(Mean square error,MSE)及收敛速度评估均优于对比算法,并具备对复杂运动及局部遮挡的适应能力.

New Snake Genome Study Sheds Light on Limb Loss and Sensory Superpowers

A sweeping genomic study of snakes,published in Cell,has shed new light on the genetic basis of their unique traits and evolutionary adaptations.An international team,led by Dr.LI Jiatang from the CAS Chengdu Institute of Biology(CIB),analyzed the genomes of 25 snake species with a wide diversity,including blind snakes,pythons,and pit vipers.This extensive dataset allowed the researchers to track changes in the snake genome over 117 million years of evolution,and identify genetic modifications linked to limb loss,infrared sensing,asymmetrical lung development,and other distinctive snake features.

一种基于遗传算法的双T-Snake模型图像分割方法

Snake的初衷是为了进行图像分割,但它对初始位置过于敏感,且不能处理拓扑结构改变的问题。初始位置的敏感性可以用遗传算法来克服,因为它是一种全局优化算法,且有良好的数值稳定性。为了更精确地进行图像分割,本文提出了一种基于遗传算法的双T-Snake模型图像分割方法,它将双T-Snake模型解作为遗传算法的搜索空间,这既继承了T-Snake模型的拓扑改变能力,又加快了遗传算法的收敛速度。由于它利用遗传算法的全局优化性能,克服了Snake轮廓局部极小化的缺陷,从而可得到对目标的更精确的分割。将其应用于左心室MRI图像的分割,取得了较好的效果。

自由差分运算与直交型Snake模型

自由差分运算能够突破传统微分算子的模板运算模式 ,把对图像这种二维信号的微分计算转化成一维的方式进行 ,使计算方向可以根据实际问题灵活选择 直交型Snake模型基于任意曲线可由多边形进行逼近的思想 ,借助自由差分运算 ,把本应沿曲线法线方向计算的灰度梯度转化成在多边形各边的直交线上分析灰度的相对变化或绝对变化 在曲线的演化过程中 ,该模型以目标曲线的特征为指导 ,以基本多边形为依托 ,通过在直交线上进行差分操作 ,从而把轮廓变化的信息和图像灰度变化的信息联系在一起 ,使得所提取的轮廓曲线的特征不断地逼近目标曲线的特征 与已有的Snake模型相比 ,直交型Snake模型通过强调高层视觉和底层信息之间的相互联系在曲线演化过程中的作用 ,使得信息的处理流程处于闭环状态 在对畸形物体的轮廓提取实验中 。

基于GVF的骨架snake模型

提出了一种基于梯度矢量流 (GVF)的快速收敛骨架snake算法。首先利用GVF变换后凹腔内外力的特点检测出物体的骨架 ,然后以骨架作为指引修改其外力的方向和大小 ,以达到快速收敛。该算法不但能解决GVF不能解决的深凹腔问题 ,而且在速度上也远远超过GVF。

基于B-Snake的三维图像骨架化方法

3D图像数据由于其本身的复杂性,对其进行骨架化一直是3D图像处理中的一个难点问题。文中提出了一种B-Snake骨架化算法及B-Snake能量最小化求解法,同时讨论一种骨架化算法的评价方法。B-Snake骨架化算法获取的骨架其连通性和光滑性隐含于B-Spline表达式中,而且在中心性及抗噪声性等方面也明显优于离散Snake算法。对模拟的测试数据和实际三维重建的植物根系图像进行了实验,结果都表明了文中提出的算法的有效性。

The SNAKE System: CEMADEN’s Landslide Early Warning System (LEWS) Mechanism

In Brazil, the prominent climate-induced disasters are floods and mass movements, with the latter being the most lethal. The spate of major landslide events, especially those in 2011, catalyzed the creation of CEMADEN (National Center for Monitoring and Early Warning of Natural Disasters). This article introduces one of CEMADEN’s pivotal systems for early landslide warnings and traces its developmental timeline. The highlighted SNAKE System epitomizes advancements in digital monitoring, forecasting, and alert mechanisms. By leveraging precipitation data from pluviometers in observed municipalities, the system bolsters early warnings related to potential mass movements, like planar slides and debris flows. Its deployment in CEMADEN’s Situation Room attests to its suitability for overseeing high-risk municipalities, attributed primarily to its robustness and precision.

基于Snake模型的医学图像分割

基于Snake模型的图像分割技术是近年来图像处理领域的研究热点之一。Snake模型承载上层先验知识并融合了图像的底层特征,针对医学图像的特殊性,能有效地应用于医学图像的分割中。本文对各种基于Snake模型的改进算法和进化模型进行了研究,并重点梳理了最新的研究成果,以利于把握基于Snake模型的医学图像分割方法的脉络和发展方向。