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Learning curve of totally thoracoscopic pulmonary segmentectomy

Weibing Wu, Jing Xu, Wei Wen, Yue Yu, Xinfeng Xu, Quan Zhu, Liang Chen

《医学前沿（英文）》 2018年第12卷第5期页码 586-592 doi: 10.1007/s11684-017-0566-z

摘要：

Totally thoracoscopic pulmonary segmentectomy (TTPS) is a feasible and safe technique that requires advanced thoracoscopic skills and knowledge of pulmonary anatomy. However, data describing the learning curve of TTPS have yet to be obtained. In this study, 128 patients who underwent TTPS between September 2010 and December 2013 were retrospectively analyzed to evaluate the learning curve and were divided chronologically into three phases, namely, ascending phase (A), plateau phase (B), and descending phase (C), through cumulative summation (CUSUM) for operative time (OT). Phases A, B, and C comprised 39, 33, and 56 cases, respectively. OT and blood loss decreased significantly from phases A to C (P <0.01), and the frequency of intraoperative bronchoscopy for target bronchus identification decreased gradually (A, 8/39; B, 4/33; C, 3/56; P = 0.06). No significant differences were observed in demographic factors, conversion, complications, hospital stay, and retrieved lymph nodes among the three phases. Surgical outcomes and techniques improved with experience and volume. CUSUM_OT indicated that the learning curve of TTPS should be more than 72 cases.

关键词： thoracoscopic segmentectomy learning curve CUSUM

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学习曲线及在工业生产运作研究中的应用综述

陈志祥

《中国工程科学》 2007年第9卷第7期页码 82-88

摘要：

学习曲线是一种通过生产者行为学习与经验积累而得到改进的生产产出的特征函数，利用学习曲线可以科学地制定成本计划，改善作业计划、劳动定额与劳力规划，质量改善等。对国际上的研究文献、学习曲线的表现形式及其特点进行分析，探讨了几个新的应用动向。

关键词：学习曲线运作管理行为研究

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A Review on Shale Gas Development in Fuling

Zhi-gang Wang

《工程管理前沿（英文）》 2015年第2卷第1期页码 76-81 doi: 10.15302/J-FEM-2015011

摘要： The Fuling Marine Shale Deposit contains vast gas resources. Due to tectonic activities, complex surface and geological conditions, significant differences make it unlike that of North America. Thus, it is not suitable to completely copy the technology and the development model from North America. Therefore we need engineering technology and a business development model fit for Fuling Shale Gas Development (FSGD). Through difficulties and characteristics analysis of the shale gas development area, we determined geological engineering design methods and integrated workflow, established a series of the core technologies, including horizontal well drilling with long laterals, staged fracturing and completion technology, developed main fluids, tools and equipment, put forward “well factory” mode in mountain region and “full cycle learning and system optimization” management methods. Break through was made in China’s first large-scale shale gas fields commercial development. By the end of 2014, production capacity reached 25 × 10 m /a, and cumulative gas production reached 12.24 × 10 m , which made a solid foundation to build production capacity of 50 × 10 m /a in 2015 and 100 × 10 m /a in 2017. Not only has FSGD established a demonstration for the other shale gas fields’ development, but also will be taken as reference to other large and extra-large construction projects of the industry.

关键词： Fuling shale gas drilling and completion staged fracturing learning curve capacity building commercial development

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Is there an inverted U-shaped curve?Empirical analysis of the Environmental Kuznets Curve in agrochemicals

Fei LI,Suocheng DONG,Fujia LI,Libiao YANG

《环境科学与工程前沿（英文）》 2016年第10卷第2期页码 276-287 doi: 10.1007/s11783-014-0700-y

摘要： As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environmental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in mainland China from 1989 to 2009. The empirical results indicate a positive long-run co-integrated relationship between the environmental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000–13,000, 85,000–89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phosphorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.

关键词： Environmental Kuznets Curve agrochemical China

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边信道攻击和学习向量量化 Article

Ehsan SAEEDI, Yinan KONG, Md. Selim HOSSAIN

《信息与电子工程前沿（英文）》 2017年第18卷第4期页码 511-518 doi: 10.1631/FITEE.1500460

摘要：本文对椭圆曲线加密（Elliptic curve cryptography, ECC）的现场可编程门阵列（field-programmable gate array, FPGA）实现展开了新的实验研究，探讨了基于学习向量量化（Learning vector quantization, LVQ）神经网络的边信道信息表征的效率。

关键词：边信道攻击；椭圆曲线加密；多类分类；学习向量量化

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21世纪我国光伏产业发展战略思考

赵玉文

《中国工程科学》 2001年第3卷第7期页码 17-20

摘要：

从我国光伏产业与国际的差距以及即将"入世"所面临的挑战出发，分析了世界光伏产业发展的趋势、速度及我国光伏产业应采取的发展战略，对21世纪前期的发展作出初步预测，同时还分析了为实现发展战略构想应采取的驱动措施。分析表明，世界光伏产业在2000～2010年期间将以28.5%的年增长速率发展，如果我们能抓住"入世"机遇在同一期间以35％的年增长率发展，就能使我国光伏发电成本在2010年与国际趋同。

关键词：光伏产业发展战略发电成本经验曲线政策法规

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Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

《结构与土木工程前沿（英文）》 2019年第13卷第1期页码 92-102 doi: 10.1007/s11709-018-0472-8

摘要： The scaled boundary finite element method (SBFEM) is applied to the static analysis of two dimensional elasticity problem, boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force, general boundary conditions, and bounded and unbounded domain. This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve. Three linear elasticity problems are presented to verify the proposed method with the analytical solution. Numerical examples show the accuracy and efficiency of the proposed method, and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.

关键词： exact geometry circular defining curve general boundaries SBFEM

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Research on physical shape preserving curve reconstruction

TANG Kelun, ZHANG Xiangwei, CHENG Siyuan, XIONG Hanwei, ZHANG Hong

《机械工程前沿（英文）》 2007年第2卷第3期页码 305-309 doi: 10.1007/s11465-007-0054-2

摘要： Fusion of various data is an effective way to improve the precision and efficiency of acquiring information in reverse engineering. A method of physical shape preserving curve reconstruction is proposed to better realize the data fusion of coordinate measuring machine (CMM) and visual information. From the principle of materials mechanics, the strain energy of the curve corresponding to the distortion is advanced as the internal energy, and the elastic potential energy of the curve is established, using a few precise measured data points as the equilibrium position, to be the external energy. On the basis of the principle of variation calculus, the basic spline finite element method (B-spline FEM) is used to determine the equilibrium position of curve deformation. Numerical simulation indicates that there is an extremely good agreement between the new fitted curve and the actual curve.

关键词： information CMM Numerical simulation effective coordinate measuring

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Interpolation of a spline developable surface between a curve and two rulings

Alicia CANTÓN,Leonardo FERNÁNDEZ-JAMBRINA

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 173-190 doi: 10.1631/FITEE.14a0210

摘要： In this paper we address the problem of interpolating a spline developable patch bounded by a given spline curve and the first and the last rulings of the developable surface. To complete the boundary of the patch, a second spline curve is to be given. Up to now this interpolation problem could be solved, but without the possibility of choosing both endpoints for the rulings. We circumvent such difficulty by resorting to degree elevation of the developable surface. This is useful for solving not only this problem, but also other problems dealing with triangular developable patches.

关键词： Developable surfaces Spline surfaces Blossoms

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Principle and curve of planetary indexing cam mechanisms

LIU Ming-tao, ZHANG Ce, YANG Yu-hu

《机械工程前沿（英文）》 2006年第1卷第4期页码 475-478 doi: 10.1007/s11465-006-0063-6

摘要： A new type of planetary indexing cam mechanism called type !c is presented. The transmission principle of type !c is discussed. Based on the principle of formation of conjugate tooth contour, the equations of the cam s pitch curve are derived. The continuity and symmetry of the cam s pitch curve are also analyzed. It can be concluded that: 1) This type has no output institution so the output precision can be improved; 2) The asymmetrical two-ring structure is used to overcome dead point and its phase angle is equal to (π - 2π/n); 3) The continuous condition of the cam s pitch curve is that the average transmission ratio is -n in an intermittent motion period.

关键词： continuity planetary average transmission symmetry intermittent

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应急状态下新冠流行曲线预测的方法学研究——基于北京市百度搜索和传统流感样病例监测 Article

张婷, 杨柳飏, 韩萱, 范国辉, 钱捷, 胡选成, 赖圣杰, 李中杰, 刘志敏, 冯录召, 杨维中

《工程（英文）》 2023年第31卷第12期页码 112-119 doi: 10.1016/j.eng.2023.08.006

摘要：

监测是传染病防控的关键环节。在全球暴发的新冠疫情暴露了传统监测方法的局限性，但也为探索新的监测方法提供了契机。本研究旨在利用百度搜索指数和流感样病例（ILI）监测数据，估计SARS-CoV-2的变异株奥密克戎BF.7在北京市应急状态下的传播和流行趋势。本研究创新性地提出了一种复合模型[多注意力双向门控循环单元（MABG）-易感-暴露-感染-恢复（SEIR）]，该模型利用深度学习算法（MABG）对ILI历史数据和发烧、发热、咳嗽、咽痛、退烧药、流涕等多种百度指数流感样症状相关关键词进行分析。基于百度指数以及ILI与新冠病毒感染之间的相关性，构建了一个估计SARS-CoV-2传播和流行趋势的传染病传播动力学模型（SEIR）。在新冠病毒感染大流行期间，当常规监测措施暂停时，ILI可以作为评估新冠病毒感染流行病学趋势的重要指标。研究结果显示，北京市自2022年12月17日起累计感染率超过80.25%（95% CI: 77.51%~82.99%），本研究预测疫情高峰时间为2022年12月12日，现存感染者数量的高峰将在该高峰后的三天出现。有效再生数（R_t）代表流行期间某一时间点单个感染者所致平均继发感染人数，该值自2022年12月17日一直低于1。本研究强调，传统的疾病监测系统应辅之以现代监测数据，例如具有先进技术支持的网络信息数据源。现代监测渠道应主要用于监测新发传染病和疾病暴发。应建立对新冠病毒感染的症状监测，以跟踪疫情趋势、疾病严重程度和医疗资源需求。

关键词：新冠病毒感染流行曲线百度搜索引擎流感样病例深度学习传播动力学模型

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Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿（英文）》 2019年第13卷第3期页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要： The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词： piezoelectricity impedance curve mode shapes inverse problem flaw detection curve shifting

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交换式以太网NC建模与实时性能分析

王晓欣,刘鲁源,刘昆,马津艳

《中国工程科学》 2006年第8卷第6期页码 55-59

摘要：

交换式以太网的实时性能分析是工业以太网研究领域的一个热点课题，目前还没有一个有效的数学模型来对其进行描述。通过对典型交换机结构的分析，应用网络微积分理论建立了交换机的服务曲线模型，该模型将交换机中的数据流分为实时数据和非实时数据，并得到了最大延迟值和最大缓存需求值等，最大延迟为交换机的实时应用提供了理论边界值，最大缓存需求值为在实时工业环境中的交换机构建提供了理论参考。

关键词：网络微积分交换机到达曲线服务曲线延迟