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A multiscale-contour-based interpolation framework for generating a time-varying quasi-dense point cloud

Chu-hua HUANG,Dong-ming LU,Chang-yu DIAO

《信息与电子工程前沿（英文）》 2016年第17卷第5期页码 422-434 doi: 10.1631/FITEE.1500316

摘要： To speed up the reconstruction of 3D dynamic scenes in an ordinary hardware platform, we propose an efficient framework to reconstruct 3D dynamic objects using a multiscale-contour-based interpolation from multi-view videos. Our framework takes full advantage of spatio-temporal-contour consistency. It exploits the property to interpolate single contours, two neighboring contours which belong to the same model, and two contours which belong to the same view at different times, corresponding to point-, contour-, and model-level interpolations, respectively. The framework formulates the interpolation of two models as point cloud transport rather than non-rigid surface deformation. Our framework speeds up the reconstruction of a dynamic scene while improving the accuracy of point-pairing which is used to perform the interpolation. We obtain a higher frame rate, spatio-temporal-coherence, and a quasi-dense point cloud sequence with color information. Experiments with real data were conducted to test the efficiency of the framework.

关键词： Multi-view video Free-viewpoint video Point-pair Multiscale-contour-based interpolation Spatio-temporal-contour Consistency Time-varying point cloud sequence

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基于时空数据的地下空间基础设施智能监测系统 Review

杜博文, 叶俊辰, 朱合华, 孙磊磊, 杜彦良

《工程（英文）》 2023年第25卷第6期页码 194-203 doi: 10.1016/j.eng.2022.07.016

摘要：

基于时空大数据的智能感知、机理认知和劣化预知，不仅促进了基础设施安全的发展，同时也是基础设施建设向智能化转变的基础理论和关键技术。地下空间利用的发展，形成了深、大、聚的三大特征和立体的城市布局。然而，与地上的建筑物和桥梁相比，发生在地下的疾病和退化更为隐蔽，难以识别，在建设和服务期间仍然存在许多挑战。针对这一问题，本文总结了现有的方法，并在现实世界的空间安全管理中评估了它们的长处和短处，并在统一的智能监控系统中，讨论关键科学问题和解决方案。

关键词：结构健康监测地下空间结构机器学习时空数据

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Spatio-temporal variations of water quality in Yuqiao Reservoir Basin, North China

Yuan XU,Ruqin XIE,Yuqiu WANG,Jian SHA

《环境科学与工程前沿（英文）》 2015年第9卷第4期页码 649-664 doi: 10.1007/s11783-014-0702-9

摘要： Fuzzy comprehensive assessment and multivariate statistical techniques including cluster analysis, discriminant analysis, principal component analysis, and factor analysis were applied to analyze the water quality status of Yuqiao Reservoir Basin, North China, for assessing its spatio-temporal variations and identifying potential pollution sources. In this paper, we considered data for 14 water quality parameters collected during 1990–2004 at 7 water quality monitoring sites. The results of fuzzy comprehensive assessment revealed that water quality in Yuqiao Reservoir Basin showed a downtrend from 1990 to 2001 with fluctuation, and a slowly upward trend after 2001. The major water quality belonged to Class III and IV. Besides, hierarchical cluster analysis divided 7 monitoring sites into two groups (Group A and B), and 12 months into three periods (low-flow (LF), normal-flow (NF), and high-flow (HF) period). Temp, pH, SS, T-har, DO, NO -N and TP were identified as significant variables affecting spatial variations, and Temp, pH and NO -N were identified as significant variables affecting temporal variations by discriminant analysis. Factor analysis identified four latent pollution sources for water quality variations: nutrient pollution, organic pollution, inorganic pollution, and natural pollution. Moreover, for Group A regions, pollution inputs mainly came from domestic wastewater and industrial sewage. For Group B regions, it is more likely that water pollution resulted from the combined effects of domestic wastewater, hospital wastewater, agriculture runoff, and fishpond discharge, as well as the incoming water from upstream.

关键词： Fuzzy comprehensive assessment multivariate statistical analysis water quality

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Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan

Bin QUAN, M. J. M. R?MKENS, Rui LI, Fang WANG, Jie CHEN

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 564-572 doi: 10.1007/s11783-011-0348-9

摘要： The Liupan Mountains are located in the southern Ningxia Hui Autonomous Region of China, that forms an important divide between landforms and bio-geographic regions. The populated part of the Liupan Mountain Region has suffered tremendous ecological damage over time due to population pressure, excessive demand and inappropriate use of agricultural land resources. To present the relationship between land use/cover change and spatio-temporal variation of soil erosion, data sets of land use between the late 1980s and 2000 were obtained from Landsat Thematic Mapper (TM) imagery, and spatial models were used to characterize landscape and soil erosion conditions. Also, soil erosion in response to land use and land cover change were quantified and analyzed using data from geographical information systems and remote sensing. Soil erosion by water was the dominant mode of soil loss, while soil erosion by wind was only present on a relatively small area. The degree of soil erosion was classified into five severity classes: slight, light, moderate, severe, and very severe. Soil erosion in the Liupan Mountain Region increased between the late 1980s and 2000, both in terms of acreage and severity. Moderate, severe, and very severe eroded areas accounted for 54.86% of the total land area. The lightly eroded area decreased, while the moderately eroded area increased by 368817 ha (22%) followed by severe erosion with 146552 ha (8.8%), and very severe erosion by 97067.6 ha (5.8%). Soil loss on sloping cropland increased with slope gradients. About 90% of the cropland was located on slopes less than 15°. Most of the increase in soil erosion on cropland was due to conversion of steep slopes to cropland and degradation of grassland and increased activities. Soil erosion was severe on grassland with a moderate or low grass cover and on dry land. Human activities, cultivation on steep slopes, and overgrazing of pastures were the main reasons for the increase in erosion severity.

关键词： land use/land cover change soil erosion geographical information system remote sensing Liupan Mountain Region

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一种时空权重和边缘自适应的扫描格式转换

丁勇,陆生礼,时龙兴

《中国工程科学》 2007年第9卷第10期页码 49-54

摘要：

为实现隔行扫描到逐行扫描的视频扫描格式转换，提出了一种时空权重和边缘自适应的去隔行算法，主要包括运动估计、小角度边缘搜索、时空权重计算、自适应插值等。该算法通过4场相邻像素的最大灰度变化与运动阈值比较实现对当前像素的运动估计，采用自适应搜索半径和并行搜索树的方法实现小角度边缘检测，并且增加对半像素边缘的考虑实现最小6°边缘的检测，最后通过时空权重自适应的插值算法实现去隔行处理，取得很好的处理效果。

关键词：扫描格式转换运动估计边缘搜索时空权重自适应插值去隔行

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岩溶地面塌陷形成机理与成因模式研究——以山东泰安—莱芜为例

高宗军

《中国工程科学》 2008年第10卷第4期页码 38-43

摘要：

山东省泰安—莱芜地区自20世纪70年代中期开始就陆续由于岩溶水的排除而出现严重的地面塌陷，属于隐伏灰岩区岩溶地面塌陷，给当地社会和经济发展带来了巨大危害。总结归纳了该地区岩溶地面塌陷的时空分布特征，论述了其产生的地质条件和人为诱发因素，探讨了岩溶地面塌陷的形成机理，并针对存在的问题探索了其成因模式，最后给出了今后该类研究的思路。

关键词：泰安—莱芜岩溶地面塌陷时空分布特征形成机理成因模式

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灵活可变的运动图像的分割算法

赵彦玲,张之超,高振,张庆超

《中国工程科学》 2006年第8卷第5期页码 84-87

摘要：

运动图像的分割在基于内容的视频编码及视频检索中占有重要的地位。利用运动图像帧中的时空域信息，提出了一种分割运动对象的方法。其最大的特点是灵活性，可以根据序列的实际情况来选择算法。实验证明分割效果较好并节省了处理时间。

关键词：时空结合运动区域运动对象形态梯度算子灵活性

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基于相邻关系的等高线树建立算法研究

郭沛沛,李成名,殷勇

《中国工程科学》 2013年第15卷第5期页码 42-46

摘要：

等高线树在提取地形线、地貌综合等方面具有重要的应用意义。常用的等高线树表达的是等高线的层次关系，直接表达等高线的包含和邻接关系，建树过程复杂，对数据要求较高，需要对数据进行预处理。本文将图幅内等高线按照是否闭合分为两类，分别对两类等高线群进行建树，最后将两个独立的等高线树合并，形成完整的等高线树。最后生成的等高线树表示了等高线之间的相邻关系，再借助其高程值就可以判断出等高线之间的包含邻接关系，算法容易理解，程序实现简单。

关键词：等高线树相邻关系高程值闭合等高线不闭合等高线

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Image automatic mosaics based on contour phase correlation

ZHANG Jing, HU Zhiping, OU Zongying, LIU Zhitai

《机械工程前沿（英文）》 2007年第2卷第2期页码 228-234 doi: 10.1007/s11465-007-0040-8

摘要： The image planar mosaics is studied, and an image automatic mosaics algorithm on the basis of contour phase correlation is proposed in this paper. To begin with, by taking into account mere translations and rotations between images, a contour phase correlation algorithm is used to realize the preliminary alignments of images, and the initial projective transformation matrices are obtained. Then, an optimization algorithm is used to optimize the initial projective transformation matrices, and complete the precise image mosaics. The contour phase correlation is an improvement on the conventional phase correlation in two aspects: First, the contours of images are extracted, and the phase correlation is applied to the contours of images instead of the whole original images; Second, when there are multiple peak values approximate to the maximum peak value in the ? function array, their corresponding translations can be regarded as candidate translations and calculated separately, and the best translation can be determined by the optimization of conformability of two images in the overlapping area. The running results show that the proposed algorithm can consistently yield high-quality mosaics, even in the cases of poor or differential lighting conditions, existences of minor rotations, and other complicated displacements between images.

关键词： function conventional multiple algorithm correlation algorithm

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Chord error constraint based integrated control strategy for contour error compensation

Tie ZHANG, Caicheng WU, Yanbiao ZOU

《机械工程前沿（英文）》 2020年第15卷第4期页码 645-658 doi: 10.1007/s11465-020-0601-7

摘要： As the traditional cross-coupling control method cannot meet the requirements for tracking accuracy and contour control accuracy in large curvature positions, an integrated control strategy of cross-coupling contour error compensation based on chord error constraint, which consists of a cross-coupling controller and an improved position error compensator, is proposed. To reduce the contour error, a PI-type cross-coupling controller is designed, with its stability being analyzed by using the contour error transfer function. Moreover, a feed rate regulator based on the chord error constraint is proposed, which performs speed planning with the maximum feed rate allowed by the large curvature position as the constraint condition, so as to meet the requirements of large curvature positions for the chord error. Besides, an improved position error compensation method is further presented by combining the feed rate regulator with the position error compensator, which improves the tracking accuracy via the advance compensation of tracking error. The biaxial experimental results of non-uniform rational B-splines curves indicate that the proposed integrated control strategy can significantly improve the tracking and contour control accuracy in biaxial contour following tasks.

关键词： cross-coupling controller contour error tracking error position error compensator feed rate regulator

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Realtime prediction of hard rock TBM advance rate using temporal convolutional network (TCN) with tunnel

Zaobao LIU; Yongchen WANG; Long LI; Xingli FANG; Junze WANG

《结构与土木工程前沿（英文）》 2022年第16卷第4期页码 401-413 doi: 10.1007/s11709-022-0823-3

摘要： Real-time dynamic adjustment of the tunnel bore machine (TBM) advance rate according to the rock-machine interaction parameters is of great significance to the adaptability of TBM and its efficiency in construction. This paper proposes a real-time predictive model of TBM advance rate using the temporal convolutional network (TCN), based on TBM construction big data. The prediction model was built using an experimental database, containing 235 data sets, established from the construction data from the Jilin Water-Diversion Tunnel Project in China. The TBM operating parameters, including total thrust, cutterhead rotation, cutterhead torque and penetration rate, are selected as the input parameters of the model. The TCN model is found outperforming the recurrent neural network (RNN) and long short-term memory (LSTM) model in predicting the TBM advance rate with much smaller values of mean absolute percentage error than the latter two. The penetration rate and cutterhead torque of the current moment have significant influence on the TBM advance rate of the next moment. On the contrary, the influence of the cutterhead rotation and total thrust is moderate. The work provides a new concept of real-time prediction of the TBM performance for highly efficient tunnel construction.

关键词： hard rock tunnel tunnel bore machine advance rate prediction temporal convolutional networks soft computing construction big data

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Temporal trend of mortality from major cancers in Xuanwei, China

null

《医学前沿（英文）》 2015年第9卷第4期页码 487-495 doi: 10.1007/s11684-015-0413-z

摘要：

Although a number of studies have examined the etiology of lung cancer in Xuanwei County, China, other types of cancer in this county have not been reported systematically. This study aimed to investigate the temporal trend of eight major cancers in Xuanwei County using data from three mortality surveys (1973–1975, 1990–1992, and 2004–2005). The Chinese population in 1990 was used as a standard population to calculate age-standardized mortality rates. Cancers of lung, liver, breast, brain, esophagus, leukemia, rectum, and stomach were identified as the leading cancers in this county in terms of mortality rate. During the three time periods, lung cancer remained as the most common type of cancer. The mortality rates for all other types of cancer were lower than those of the national average, but an increasing trend was observed for all the cancers, particularly from 1990–1992 to 2004–2005. The temporal trend could be partly explained by changes in risk factors, but it also may be due to the improvement in cancer diagnosis and screening. Further epidemiological studies are warranted to systematically examine the underlying reasons for the temporal trend of the major cancers in Xuanwei County.

关键词： cancer mortality Xuanwei temporal trend

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The temporal changes of the concentration level of typical toxic organics in the river sediments around

Qiang Li, Xiong Xu, Yaoyao Fang, Ruiyang Xiao, Donghong Wang, Wenjue Zhong

《环境科学与工程前沿（英文）》 2018年第12卷第6期 doi: 10.1007/s11783-018-1054-7

摘要：

The current situation of typical organics in the sediments around Beijing was unclear.

56 kinds of typical toxic organics were detected in this article.

Historical data was compared with the data in this study.

The change of different organics in the sediments around Beijing was concluded.

关键词： Organic compounds Endocrine disrupters Sediments Concentration Temporal changes

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The effect of texture and irrigation on the soil moisture vertical-temporal variability in an urban artificial

Xiaofeng ZHANG,Xu ZHANG,Guanghe LI

《环境科学与工程前沿（英文）》 2015年第9卷第2期页码 269-278 doi: 10.1007/s11783-014-0672-y

摘要： Soil moisture variability in natural landscapes has been widely studied; however, less attention has been paid to its variability in the urban landscapes with respect to the possible influence of texture stratification and irrigation management. Therefore, a case study was carried out in the Beijing Olympic Forest Park to continuously monitor the soil in three typical profiles from 26 April to 11 November 2010. The texture stratification significantly affected the vertical distribution of moisture in the non-irrigated profile where moisture was mostly below field capacity. In the profile where irrigation was sufficient to maintain moisture above field capacity, gravity flow led to increased moisture with depth and thus eliminated the influence of texture. In the non-irrigated sites, the upper layer (above 80 cm) exhibited long-term moisture persistence with the time scale approximating the average rainfall interval. However, a coarse-textured layer weakened the influence of rainfall, and a fine-textured layer weakened the influence of evapotranspiration, both of which resulted in random noise-like moisture series in the deeper layers. At the irrigated site, frequent irrigation neutralized the influence of evapotranspiration in the upper layer (above 60 cm) and overshadowed the influence of rainfall in the deeper layer. As a result, the moisture level in the upper layer also behaved as a random noise-like series; whereas due to deep transpiration, the moisture of the deep layer had a persistence time-scale longer than a month, consistent with characteristic time-scales found for deep transpiration.

关键词： moisture vertical distribution moisture temporal variation texture stratification irrigation meteorological forcing urban landscape

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Spatial and Temporal Distribution of PM

Xiao-hong Chen,Xiang-bo Tang

《工程管理前沿（英文）》 2016年第3卷第2期页码 171-181 doi: 10.15302/J-FEM-2016017

摘要： Utilizing the initial hourly monitoring data of PM concentrations at 23 monitoring sites across the Chang-Zhu-Tan city cluster between January 2013 and February 2014 that released in Real-time Air Quality Reporting System in Hunan Province, this paper draws diagrams and analyzes the change rule of the pollutants concentration over time. In addition, this paper studies the regional distribution of PM seasonal pollution in the vicinity of the monitoring sites using ArcGIS geographic information system with the Kriging interpolation method. On this basis, this paper puts forward some effective control strategies to cope with regional PM pollution combined with the information of industry distribution and development status in the Chang-Zhu-Tan city cluster.

关键词： PM_2.5 spatial and temporal distribution ArcGIS the chang-Zhu-Tan city cluster