New normalized nonlocal hybrid level set method for image segmentation

This article introduces a new normalized nonlocal hybrid level set method for image segmentation.Due to intensity overlapping,blurred edges with complex backgrounds,simple intensity and texture information,such kind of image segmentation is still a challenging task.The proposed method uses both the region and boundary information to achieve accurate segmentation results.The region information can help to identify rough region of interest and prevent the boundary leakage problem.It makes use of normalized nonlocal comparisons between pairs of patches in each region,and a heuristic intensity model is proposed to suppress irrelevant strong edges and constrain the segmentation.The boundary information can help to detect the precise location of the target object,it makes use of the geodesic active contour model to obtain the target boundary.The corresponding variational segmentation problem is implemented by a level set formulation.We use an internal energy term for geometric active contours to penalize the deviation of the level set function from a signed distance function.At last,experimental results on synthetic images and real images are shown in the paper with promising results.

Evaluation of regional water resources carrying capacity based on binary index method and reduction index method

Based on the regional water resources carrying capacity(WRCC)evaluation principles and evaluation index system in the National Technical Outline of Water Resources Carrying Capacity Monitoring and Early Warning(hereafter referred to as the Technical Outline),this paper elaborates on the collection and sorting of the basic data of water resources conditions,water resources development and utilization status,social and economic development in basins,analysis and examination of integrity,consistency,normativeness,and rationality of the basic data,and the necessity of WRCC evaluation.This paper also describes the technique of evaluating the WRCC in prefecture-level cities and city-level administrative divisions in the District of the Taihu Lake Basin,which is composed of the Taihu Lake Basin and the Southeastern River Basin.The evaluation process combines the binary index evaluation method and reduction index evaluation method.The former,recommended by the Technical Outline,uses the total water use and the amount of exploited groundwater as evaluation indices,showing stronger operability,while the latter is developed by simplifying and optimizing the comprehensive index system with greater systematicness and completeness.The mutual validation and adjustment of the results of the above-mentioned two evaluation methods indicate that the WRCC of the District of the Taihu Lake Basin is overloaded in general because some prefecture-level cities and city-level administrative divisions in the Taihu Lake Basin and the Southeastern River Basin are in a severely overloaded state.In order to explain this conclusion,this paper analyzes the causes of WRCC overloading from the aspects of basin water environment,water resources development and utilization,water resources regulation and control ability,water resources utilization efficiency,and water resources management.

Impacts of climate change and human activities on water resources in the Ebinur Lake Basin, Northwest China

Changing climatic conditions and extensive human activities have influenced the global water cycle.In recent years,significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake Basin in Xinjiang,Northwest China.In this paper,variations of runoff,temperature,precipitation,reference evapotranspiration,lake area,socio-economic water usage,groundwater level and water quality in the Ebinur Lake Basin from 1961 to 2015 were systematically analyzed by the Mann-Kendall test methods(M-K)mutation test,the cumulative levelling method,the climate-sensitive method and land-use change index.In addition,we evaluated the effects of human activities on land use change and water quality.The results reveal that there was a significant increase in temperature and precipitation from 1961 to 2015,despite a decrease in reference evapotranspiration.The Wenquan station was not significantly affected by human activities as it is situated at a higher altitude.Runoff at this station increased significantly with climate warming.In contrast,runoff at the Jinghe station was severely affected by numerous human activities.Runoff decreased without obvious fluctuations.The contributions of climate change to runoff variation at the Jinghe and Wenquan stations were 46.87%and 58.94%,respectively;and the contributions of human activities were 53.13%and 41.06%,respectively.Land-use patterns in the basin have changed significantly between 1990 and 2015:urban and rural constructed lands,saline-alkali land,bare land,cultivated land,and forest land have expanded,while areas under grassland,lake,ice/snow and river/channel have declined.Human activities have dramatically intensified land degradation and desertification.From 1961 to 2015,both the inflow into the Ebinur Lake and the area of the lake have declined year by year;groundwater levels have dropped significantly,and the water quality has deteriorated during the study period.In the oasis irrigation area below the runoff pass,human activities mainly influenced the utilization mode and quantity of water resources.Changes in the hydrology and quantity of water resources were driven primarily by the continuous expansion of cultivated land and oasis,as well as the growth of population and the construction of hydraulic engineering projects.After 2015,the effects of some ecological protection projects were observed.However,there was no obvious sign of ecological improvement in the basin,and some environmental problems continue to persist.On this basis,this study recommends that the expansion of oasis should be limited according to the carrying capacity of the local water bodies.Moreover,in order to ensure the ecological security of the basin,it is necessary to determine the optimal oasis area for sustainable development and improve the efficiency of water resources exploitation and utilization.

Strength and uniformity of EICP-treated sand under multi-factor coupling effects

Enzyme-induced carbonate precipitation(EICP)is an environment-friendly method for improving soil mechanical properties.The extraction and application of plant crude urease reduces the treatment cost.However,in terms of the efficiency of calcium carbonate production and cementation,crude urease is considered inferior to pure urease or urease bacteria.In this paper,urease extracted from soybean was used to explore the effects of urease activity,treatment method,number of treatments(NTs),injection rate,and curing time on the unconfined compressive strength and calcium carbonate distribution characteristics of EICP-treated sand.The results showed that,compared with the pre-mixing method and the two-phase method,the one-phase method produced higher strength and a more uniform distribution of calcium carbonate.The cementation efficiency decreased with the increase of urease activity.The high-rate injection can improve the treatment effect of high-activity urease.Under the same cementation level,high strength and calcium carbonate cementation efficiency can be achieved by one-phase-low-activity EICP treatment.Data Availability Statement:All data,models,and code generated or used during the study appear in the submitted article.

Active Contours and Mumford-Shah Segmentation Based on Level Sets

This paper is to detect regions (objects) boundaries, also to isolate and extract individual components from a medical image. This can be done using an active contours to detect regions in a given image, based on techniques of curve evolution, Mumford Shah functional for segmentation and level sets. The paper classified the images into different intensity regions based on Markov random field, then detected regions whose boundaries are not necessarily defined by gradient by minimizing an energy of Mumford Shah functional for segmentation which can be seen as a particular case of the minimal partition problem. In the level set formulation, the problem becomes a mean curvature flow like evolving the active contour, which will stop on the desired boundary. The stopping term does not depend on the gradient of the image, as in the classical active contour and the initial curve of level set can be anywhere in the image, and interior contours are automatically detected. The final image segmentation is one closed boundary per actual region in the image.

考虑宏观结构性能的多材料微结构拓扑优化设计

多孔微结构材料以其质量轻、比刚度/比强度高、抗冲击等优异力学性能,被广泛应用于航空航天等工程领域。相比单一材料设计,多材料设计可获得力学性能更优的微结构拓扑构型。拓扑优化是实现多材料布局设计的有效方法之一。通过构建基于差集的多材料水平集描述模型和交替活动相算法,提出了基于参数化水平集的多材料微结构拓扑优化设计方法。首先,构建了基于差集的多材料水平集描述模型,利用N个水平集函数实现N+1相材料拓扑的精确描述。然后,引入交替活动相算法,将原始N+1相多材料优化问题分解为N(N+1)/2个双相材料优化子问题,以减少设计变量与约束条件,提高计算效率。最后,采用均匀化方法计算多材料微结构的等效弹性张量,以宏观结构柔度最小化为优化目标,各相材料用量为约束条件,构建多材料微结构拓扑优化模型,并利用优化准则法实现上述优化模型的高效求解。数值算例结果表明,所提方法可有效实现多材料微结构的拓扑优化设计,所设计微结构均具有光滑的结构边界和清晰的材料界面。

中国生态经济发展水平的统计测度

加强生态环境保护、推进生态文明建设可促进经济社会全面绿色转型,赋能生态经济高质量发展。文章选取2005—2021年我国30个省份的面板数据作为研究样本,构建了生态经济发展水平测度指标体系,并使用纵向拉开档次法、等距离划分法及TOPSIS模型对生态经济发展水平进行综合测度,为生态经济高质量发展提供数据支撑。研究结果显示:2005—2021年我国生态经济发展水平增速显著,生态经济取得较大发展成效;分维度来看,生态发展效益指数最高,生态投资次之,生态产出再次,生态环境水平增速相对缓慢。据此提出加大生态经济投资力度、提高生态经济产出效率、优化生态环境保护方式、强化生态效益发展根基的建议。

雅安地区监测井水位预测效能对比研究

为提高监测井水位映震效果的判别准确度并提升预测效能,本文运用不同方法对雅安地区两条断裂附近的6口监测井水位的映震效果开展了对比判别研究。首先,使用差分法对监测井水位数据进行处理和分析。然后,将水位数据与区域地震活动性的两种参数(能级和最大震级)相结合,分析区域地震活动性与水位波动的关系。接着,在时域和频域两个层面对该组合序列进行分析处理。最后,采用Molchan图表法检验5种方法的预测效能,并选出最佳处理方法及断裂附近预测效能最优的监测井。结果表明:水位与地震活动性参数结合处理相比单独使用水位差分法具有优势,前者能够准确排除地震活动性对水位异常的干扰。6口监测井的最优预测方法各不相同,最优预测天数均在60 d内。通过比较监测井水位对地震的预测效能检验结果,确定了两条断裂区域预测效能最优的监测井。虽然水位与地震活动性两种参数结合处理并不适用于所有监测井,但该方法能够体现水位受地震活动性影响的程度。

十字形分牙法在下颌水平低位阻生齿拔除中的临床效果分析

目的 分析下颌水平低位阻生齿患者拔牙中使用十字形分牙法的效果。方法 随机从焦作市第二人民医院口腔科2021年6月至2022年6月治疗的下颌水平低位阻生齿患者中抽取65例,按照拔牙方法分组,A组(31例,常规微创拔牙法)、B组(34例,十字形分牙法),对比两组牙科畏惧调查量表(DFS)评分、术后并发症发生率、血压和心率、张口受限和肿胀程度、生活质量评定量表(SF-36)评分。结果 B组DFS评分、术后并发症发生率低于A组,差异有统计学意义(P <0.05);两组术前5 min、术后10 min心率对比差异无统计学意义(P> 0.05),拔牙时B组心率低于A组,差异有统计学意义(P <0.05);两组术前5 min、拔牙时、术后10 min血压对比差异无统计学意义(P> 0.05);B组张口受限0度占比高于A组、Ⅲ度占比低于A组,差异有统计学意义(P <0.05),两组Ⅰ度和Ⅱ度占比比较差异无统计学意义(P> 0.05);B组肿胀程度“无”占比高于A组、“重度”占比低于A组,差异有统计学意义(P <0.05),两组“轻度”和“中度”占比比较差异无统计学意义(P> 0.05);术后1个月B组SF-36评分高于A组,差异有统计学意义(P <0.05)。结论 下颌水平低位阻生齿患者拔牙中使用十字形分牙法,能降低患者对治疗的畏惧程度,对血压心率的影响较小,安全性高,术后张口受限和肿胀程度较低,快速恢复生活质量。

甲磺酸倍他司汀片结合活血化瘀法治疗感应神经性耳聋的临床探讨

目的研究甲磺酸倍他司汀片和活血化瘀法联合应用于感应神经性耳聋治疗中的临床疗效。方法选取2020年8月—2022年8月张家港市中医医院收治的48例感应神经性耳聋患者作为研究对象,按随机数表法分为两组,对照组(n=24)使用甲磺酸倍他司汀片治疗,观察组(n=24)使用甲磺酸倍他司汀片联合活血化瘀法治疗。比较两组患者的疗效和不良反应发生情况。结果治疗后,观察组的耳鸣评分(0.39±0.08)分、耳胀闷感评分(0.26±0.07)分、恶心呕吐评分(0.49±0.08)分以及眩晕评分(0.38±0.07)分均低于对照组,差异有统计学意义(t=25.648、25.390、14.176、26.301,P均<0.05);治疗后,观察组的听力测试值低于对照组,差异有统计学意义(P<0.05);两组患者的不良反应发生率对比,差异无统计学意义(P>0.05)。结论感应神经性耳聋患者应用甲磺酸倍他司汀片和活血化瘀法治疗可有效改善疾病症状,提升听力水平,且具有较高的安全性。

中国大陆成组强震活动水平的三分法及其应用

对中国大陆 1 9世纪末以来 ,M≥ 6.7成组强震活动的过程分析表明 ,可以将其活动水平分为三档 :高水平 ,中等水平和低水平强震活动期 ,它们分别对应每年平均发生大于 1 .2次、0 .6～ 1 .2次和小于 0 .6次的M≥ 6.7地震活动水平。活动过程的外推表明 ,2 1世纪的前 1 0年 ,中国大陆可能处于低水平的强震活动期 ,期中可能发生 5次 M≥ 6.7的强震 。

用于图像分割的自适应距离保持水平集演化

Li等人提出的距离保持水平集方法有传统变分水平集方法不具备的许多优点,然而,它有初始曲线必须包围目标物体或完全置于目标物体内部或外部的缺点.提出一种自适应距离保持水平集方法,它无须初始曲线包围目标物体或完全置于目标物体内部或外部,即初始曲线可以置于图像的任何地方.它能够解决原方法所不能解决的一些图像分割问题,例如,能够从任意选取的一条初始曲线出发自动检测目标物体的内外轮廓,检测多目标物体以及深度凹陷区域的边缘,并能较好地提取目标物体的弱边界.对几幅具有不同目标边界形态的合成图像和自然图像进行了实验,结果都取得了预期的分割效果.

边坡稳定验算中全面搜索的一种新方法

提出圆弧滑动法中一种新的搜索方法———三向搜索法。圆弧滑动法可以利用其共性而不局限于一些经验假设 ,在坡顶线及其下部各道坡线间都存在一个安全系数最小的圆弧 ,针对这些圆弧的寻找 ,给出了具体办法 ,并给出几个计算实例。

村级土地利用规划中的土地利用分区

为在村级土地利用规划中科学划分土地利用区,有效落实规划任务、实现规划目标,在分析村级土地利用规划特点的基础上,明确土地利用分区的任务与原则,探索建立了由产业功能区与土地用途区构成的两级分区类型体系,提出了公众参与为主、GIS技术为辅的分区方法。两级分区类型体系有利于实现土地组织利用、生产经营管理和土地利用管理的一体化。同时,在土地利用分区中贯穿公众参与式方法,有利于构建村内民主管理和业主参与土地利用管理的体制。

基于水平集方法的数字胸片图像分割

水平集方法能有效地解决曲线演化过程中的拓扑变化问题 ,基于全局特性的活动轮廓模型采用水平集方法给出的迭代解 ,能有效进行分割。用这种方法对 CR胸片图像进行分割研究 ,并根据 CR图像的特点 ,给出了只需一次演化的方法 :直接针对原图像可以得到肺部大致区域 ;而针对 CR的局部标准偏差图像可以得到肋骨的边缘图像。实验结果表明 ,该方法能很好地对

数学基本活动经验主成分和层次水平划分研究

在文献分析和调查研究基础上,给出了数学基本活动经验构成要素的研究假设,通过自编测试卷进行题目测试,借助因素分析找出了数学基本活动经验的4个主成分,分别是归纳概括、类比推广、数学表达、证明;借助聚类分析得到数学基本活动经验的层次水平划分.

多媒体高层语义框架及检索算法

针对多媒体信息检索中的'语义鸿沟'问题,提出了矩阵分裂方法的定义及其基本运算准则,描述了适用于多种多媒体信息的高层语义框架,利用该框架对多媒体信息进行高层语义检索,解决了检索多媒体信息的'语义鸿沟'问题。针对该框架提出了基于每次用户检索结果的部分优先算法,利用用户每次检索结果对高层语义分支权重进行自适应调整,从而达到提高检索效率的目的。

一种用于SAR图像分割的几何活动轮廓模型

基于SAR图像边缘检测算子和变分水平集方法,依据能量最小化准则,提出了一种新颖的几何活动轮廓模型。其基本思想是,直接定义关于水平集函数的能量泛函,并将经典模型中基于梯度算子的边缘指示函数,替换为基于ROEWA算子的边缘指示函数,提高了模型对于SAR图像的边缘检测能力;同时在新模型中加入水平集函数惩罚项,确保水平集函数逼近符号距离函数。由于该项的作用,模型的数值求解可采用简单的显式差分格式迭代,并保持较快的收敛速度。针对仿真图像、Radarsat和华东电子研究所实测数据的实验结果表明,该模型具有实现简单、分割边界定位准确和收敛速度较快等优点。

改进RSF主动轮廓模型的医学图像分割方法

针对可伸缩区域拟合能量(RSF)模型在分割某些医学图像时会存在欠分割以及轮廓收敛速度慢等问题,提出一种改进的RSF模型.利用K均值对医学图像进行全局处理,用一个新的核函数代替高斯函数.在新的核函数基础上重新建立能量泛函,并将一个内部能量项作为罚函数项引入到水平集模型中.结果表明,与传统的RSF模型相比,改进模型的分割精度提高了近40%,分割速度提高了近30%.

丘陵山区农用预检测主动调平底盘设计与试验

针对目前丘陵山区农用底盘倾斜后调平精度低、滞后的问题,提出一种预检测主动调平方法,该方法提前检测行驶前方地面情况,判断如何实施调平动作,并在底盘倾斜同时进行主动调整,可主动预防、避免或减少在崎岖不平地面上行驶作业过程中的底盘倾斜。设计了一种采用Y型可调悬架作为调平机构的农用车辆预检测主动调平底盘,分析计算了底盘悬架调整与预检测调平参数、承载能力与调平速度及调平执行策略,分析计算表明,可通过Y型可调悬架的高度调节实现底盘调平。利用样机在室外试验田中进行崎岖不平地面的行走试验验证,试验结果表明,在预检测主动调平行走过程中,丘陵山地农用预检测主动调平底盘可在精度0.5°范围内实现动态调平,验证了预检测主动调平方法以及丘陵山地农用预检测主动调平底盘设计方案的可行性。