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Joint association of physical activity/screen time and diet on CVD risk factors in 10-year-old children

null

《医学前沿（英文）》 2012年第6卷第4期页码 428-435 doi: 10.1007/s11684-012-0232-4

摘要：

The increasing prevalence of childhood overweight and obesity has been associated with an increased risk for cardiovascular disease (CVD). While several studies examined the effect of single behaviors such as physical activity (PA), sedentary behavior or diet on CVD risk, there is a lack of research on combined associations, specifically in children. Therefore, the purpose of this study was to examine the joint association of PA or screen time (ST) and diet on CVD risk factors in children. PA, ST and diet were assessed via questionnaire in 210 fifth grade students (age: 10.6±0.4 years). The healthy eating index (HEI) was subsequently calculated as indicator for diet quality. Height, weight, % body fat, and resting blood pressure were measured according to standard procedures and blood samples obtained via fingerprick were assayed for blood lipids. Total cholesterol HDL ratio (TC:HDL), mean arterial pressure (MAP), and % body fat were used as indicators of CVD risk. 55% of children did not meet current PA recommendations on at least 5 days/week and 70% exceeded current recommendations for ST. Further, only 2.5% possessed a “good” diet (HEI>80). There was no significant association of PA or ST and diet on CVD risk score. Neither TC:HDL, MAP, and % body fat nor the total CVD risk score was significantly correlated with diet, PA, or ST. Children in the high PA group, however, had significantly better diet scores. Despite the fact that self-reported PA, ST, or dietary intake were not directly related to CVD risk in this sample, higher activity levels were associated with a healthier diet and lower ST indicating an overall healthier lifestyle of this subgroup.

关键词： exercise sedentary behavior metabolic syndrome health behavior adolescents TV time healthy eating index

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Wind-induced vibration control of Hefei TV tower with fluid viscous damper

Zhiqiang ZHANG , Aiqun LI , Jianping HE , Jianlei WANG ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 249-254 doi: 10.1007/s11709-009-0038-x

摘要： The Hefei TV tower is taken as an analytical case to examine the control method with a fluid viscous damper under wind load fluctuation. Firstly, according to the random vibration theory, the effect of fluctuating wind on the tower can be modeled as a 19-dimensional correlated random process, and the wind-induced vibration analysis of the tower subjected to dynamic wind load was further obtained. On the basis of the others’ works, a bi-model dynamic model is proposed. Finally, a dynamic model is proposed to study the wind-induced vibration control analysis using viscous fluid dampers, and the optimal damping coefficient is obtained regarding the wind-induced response of the upper turret as optimization objectives. Analysis results show that the maximum peak response of the tower under dynamic wind load is far beyond the allowable range of the code. The wind-induced responses and the wind vibration input energy of the tower are decreased greatly by using a fluid viscous damper, and the peak acceleration responses of the upper turret is reduced by 43.4%.

关键词： high-rise structure wind-induced response fluid viscous damper vibration control

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设计创新对东方明珠和雅加达塔的贡献

江欢成

《中国工程科学》 1999年第1卷第1期页码 30-35

摘要：

东方明珠，塔高463.85m，高居亚洲之二，世界第三，被公认为是上海最重要的城市标志。雅加达塔，高558m，建筑面积32万m²，均堪称世界之最。东方明珠的成功，雅加达塔的中标，在很大程度上要归功于设计创新。东方明珠设计者用一串明珠来标志上海，用带斜撑的巨型空间框架作为主体结构，打破了混凝土电视塔常用的单筒体结构模式，从而获得了很好的标志性。这种结构同时很有利于抗风抗震。该塔还采用了许多高新技术，如预应力混凝土壳、双重悬挂钢结构和攀升天线等设计，它们巧妙而合理地解决了复杂的结构构造和高难度施工的问题。设计者在雅加达塔上，继承和发扬东方明珠的长处，克服它的不足，并赋予许多新的创造。为了使新的创造建立在坚实科学基础上，设计者为东方明珠塔进行了大量的试验研究工作。

关键词：创新电视塔空间框架斜撑球体钢桅杆悬挂结构

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结合全变分最小化和稀疏字典学习后处理的低剂量CT重建 Article

Yong DING, Tuo HU

《信息与电子工程前沿（英文）》 2017年第18卷第12期页码 2001-2008 doi: 10.1631/FITEE.1700287

摘要：本文提出一种结合全变分（total variation, TV）最小化和稀疏字典学习的重建方法，不仅提高了重建效果，而且通过自适应的停止策略提高了重建速度。

关键词：低剂量CT；CT成像；全变分；稀疏字典学习

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General expression for linear and nonlinear time series models

Ren HUANG, Feiyun XU, Ruwen CHEN

《机械工程前沿（英文）》 2009年第4卷第1期页码 15-24 doi: 10.1007/s11465-009-0015-z

摘要： The typical time series models such as ARMA, AR, and MA are founded on the normality and stationarity of a system and expressed by a linear difference equation; therefore, they are strictly limited to the linear system. However, some nonlinear factors are within the practical system; thus, it is difficult to fit the model for real systems with the above models. This paper proposes a general expression for linear and nonlinear auto-regressive time series models (GNAR). With the gradient optimization method and modified AIC information criteria integrated with the prediction error, the parameter estimation and order determination are achieved. The model simulation and experiments show that the GNAR model can accurately approximate to the dynamic characteristics of the most nonlinear models applied in academics and engineering. The modeling and prediction accuracy of the GNAR model is superior to the classical time series models. The proposed GNAR model is flexible and effective.

关键词： linear and nonlinear autoregressive model system identification time series analysis

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Run-time system based on LinSERCANS and Soft-PLC

Cunfeng KANG, Chong WANG, Chunmin MA, Xudong HUANG, Renyuan FEI

《机械工程前沿（英文）》 2009年第4卷第2期页码 120-124 doi: 10.1007/s11465-009-0019-8

摘要： Soft-PLC with open architecture is the direction of development in industrial automation. This paper discusses the method of communication between the interface functions of LinSERCANS under RTLinux and the external library of Soft-PLC under Windows. Based on the API HOOK theory, the communication between the interface functions of LinSERCANS and the external libraries of Soft-PLC is set up and it solves the calling functions of dynamic link libraries in different operation systems. It is able to combine LinSERCANS with the Soft-PLC, and a run-time system is developed based on the interface technology of the serial real-time communication system (SERCOS) and technology of soft-PLC. This run-time system has been used in all electronic injection molding machines and works very well.

关键词： Soft-PLC run-time system LinSERCANS dynamic link libraries

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Two-stage scheduling on batch and single machines with limited waiting time constraint

Zhongshun SHI, Zewen HUANG, Leyuan SHI

《工程管理前沿（英文）》 2017年第4卷第3期页码 368-374 doi: 10.15302/J-FEM-2017034

摘要： This study addresses the problem of two-stage scheduling on batch and single machines with limited waiting time constraint; thus, the makespan is minimized. A mixed-integer linear programming model is proposed for this problem. Three tight lower bounds and a heuristic algorithm are developed. The worst-case performance of the proposed algorithm is discussed. A hybrid differential evolution algorithm is also developed to improve the solution quantity. Numerical results show that the hybrid algorithm is capable of obtaining high-quality solutions and exhibits a competitive performance

关键词： batch machine flow shop makespan limited waiting time

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Analyzing construction safety through time series methods

Houchen CAO, Yang Miang GOH

《工程管理前沿（英文）》 2019年第6卷第2期页码 262-274 doi: 10.1007/s42524-019-0015-6

摘要： The construction industry produces a large amount of data on a daily basis. However, existing data sets have not been fully exploited in analyzing the safety factors of construction projects. Thus, this work describes how temporal analysis techniques can be applied to improve the safety management of construction data. Various time series (TS) methods were adopted for identifying the leading indicators or predictors of construction accidents. The data set used herein was obtained from a large construction company that is based in Singapore and contains safety inspection scores, accident cases, and project-related data collected from 2008 to 2015. Five projects with complete and sufficient data for temporal analysis were selected from the data set. The filtered data set contained 23 potential leading indicators (predictors or input variables) of accidents (output or dependent variable). TS analyses were used to identify suitable accident predictors for each of the five projects. Subsequently, the selected input variables were used to develop three different TS models for predicting accident occurrences, and the vector error correction model was found to be the best model. It had the lowest root mean squared error value for three of the five projects analyzed. This study provides insights into how construction companies can utilize TS data analysis to identify projects with high risk of accidents.

关键词： time series temporal construction safety leading indicators accident prevention forecasting

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Convergence to real-time decision making

James M. TIEN

《工程管理前沿（英文）》 2020年第7卷第2期页码 204-222 doi: 10.1007/s42524-019-0040-5

摘要： Real-time decision making reflects the convergence of several digital technologies, including those concerned with the promulgation of artificial intelligence and other advanced technologies that underpin real-time actions. More specifically, real-time decision making can be depicted in terms of three converging dimensions: Internet of Things, decision making, and real-time. The Internet of Things include tangible goods, intangible services, ServGoods, and connected ServGoods. Decision making includes model-based analytics (since before 1990), information-based Big Data (since 1990), and training-based artificial intelligence (since 2000), and it is bolstered by the evolving real-time technologies of sensing (i.e., capturing streaming data), processing (i.e., applying real-time analytics), reacting (i.e., making decisions in real-time), and learning (i.e., employing deep neural networks). Real-time includes mobile networks, autonomous vehicles, and artificial general intelligence. Central to decision making, especially real-time decision making, is the ServGood concept, which the author introduced in an earlier paper (2012). It is a physical product or good encased by a services layer that renders the good more adaptable and smarter for a specific purpose or use. Addition of another communication sensors layer could further enhance its smartness and adaptiveness. Such connected ServGoods constitute a solid foundation for the advanced products of tomorrow which can further display their growing intelligence through real-time decisions.

关键词： real-time decision making services goods ServGoods Big Data Internet of Things artificial intelligence wireless communications

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Damage identification in connections of moment frames using time domain responses and an optimization

《结构与土木工程前沿（英文）》 2021年第15卷第4期页码 851-866 doi: 10.1007/s11709-021-0739-3

摘要： Damage is defined as changes to the material and/or geometric properties of a structural system, comprising changes to the boundary conditions and system connectivity, adversely affecting the system’s performance. Inspecting the elements of structures, particularly critical components, is vital to evaluate the structural lifespan and safety. In this study, an optimization-based method for joint damage identification of moment frames using the time-domain responses is introduced. The beam-to-column connection in a metallic moment frame structure is modeled by a zero-length rotational spring at both ends of the beam element. For each connection, an end-fixity factor is specified, which changes between 0 and 1. Then, the problem of joint damage identification is converted to a standard optimization problem. An objective function is defined using the nodal point accelerations extracted from the damaged structure and an analytical model of the structure in which the nodal accelerations are obtained using the Newmark procedure. The optimization problem is solved by an improved differential evolution algorithm (IDEA) for identifying the location and severity of the damage. To assess the capability of the proposed method, two numerical examples via different damage scenarios are considered. Then, a comparison between the proposed method and the existing damage identification method is provided. The outcomes reveal the high efficiency of the proposed method for finding the severity and location of joint damage considering noise effects.

关键词： damage identification beam-to-column connection time-domain response optimization

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origins of schedule management: the concepts used in planning, allocating, visualizing and managing time

Lynda M. BOURNE, Patrick WEAVER

《工程管理前沿（英文）》 2018年第5卷第2期页码 150-166 doi: 10.15302/J-FEM-2018012

摘要： Getting the in the at the has always been a major organizational challenge. In ancient times this process seems to have been accomplished based on the scheme of arrangements being contained in the leader’s mind and instructions communicated verbally. Modern approaches to solving the twin challenges of first thinking through the ‘plan’ and then communicating the plan to the people who need to do ‘ ’ use sophisticated graphics, charts, diagrams, and computations. This paper traces the development of the concepts most project managers take for granted including bar charts and critical path schedules from their origins (which are far earlier than most people think) through to the modern day. The first section of the paper looks at the development of concepts that allow the visualization of time and other data. The second looks at the shift from static representations to dynamic modeling through the emergence of computers, dynamic calculations and integrated data from the 1950s to the present time.

关键词： time management scheduling CPM PERT Gantt Critical Path bar chart

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Sustainability of steel structures: towards an integrated approach to life-time engineering design

Raffaele LANDOLFO, Lucrezia CASCINI, Francesco PORTIOLI

《结构与土木工程前沿（英文）》 2011年第5卷第3期页码 304-314 doi: 10.1007/s01709-011-0123-9

摘要： Nowadays, the construction sector is more and more oriented toward the promotion of sustainability in all its activities. The goal to achieve is the optimization of performances, over the whole life-cycle, with respect to environmental, economic and social requirements. According to the latest advances, the concept of sustainability applied to constructions covers a number of branches such as life-cycle costing, ecology, durability and even structural design. Several procedures and design tools have been implemented in the framework of international research. Indeed the current trend in civil engineering research is moving towards life-time engineering, with the aim to implement integrated methodologies to consider as a whole all the sustainability requirements according to time-dependent multi-performance-based design approaches. Following a general introduction of the concept of sustainability applied to constructions, this paper presents an overview of life-time engineering methodologies according to the current state-of-the-art. In particular the methods currently received by International Standards are discussed. A special focus is devoted to the durability design of metal structures with respect to the degradation phenomena able to impair the structural capacity over time. Finally a proposal towards an integrated approach to life-time engineering design of steel structures and needs for further advances are presented.

关键词： sustainability life-time engineering performance based design durability metal structures

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Modal analysis of acoustic leak signal in pipelines using time-frequency analysis

JIAO Jing-pin, FEI Ren-yuan, HE Cun-fu, WU Bin

《机械工程前沿（英文）》 2006年第1卷第2期页码 146-150 doi: 10.1007/s11465-006-0013-3

摘要： It is important to analyze the propagation characteristics of guided waves in acoustic leak location in pipelines. In this paper, the acoustic leak signal is analyzed in the time-frequency domain. Based on the relation of time-frequency distribution of the acoustic leak signal and the dispersion curves of guided waves, the mode components of acoustic leak signals were obtained. The research can provide a guideline for the mode selection in pipeline leak location, and help improve the accuracy of leak location.

关键词： dispersion selection guided research time-frequency

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A super-element approach for structural identification in time domain

LI Jie, ZHAO Xin

《机械工程前沿（英文）》 2006年第1卷第2期页码 215-221 doi: 10.1007/s11465-006-0004-4

摘要： For most time-domain identification methods, a complete measurement for unique identification results is required for structural responses. However, the number of transducers is commonly far less than the number of structural degrees of freedom (DOFs) in practical applications, and thus make the time-domain identification methods rarely feasible for practical systems. A super-element approach is proposed in this study to identify the structural parameters of a large-scale structure in the time domain. The most interesting feature of the proposed super-element approach is its divide-and-conquer ability, which can be applied to identify large-scale structures using a relatively small number of transducers. The super-element model used for time domain identification is first discussed in this study. Then a parameterization procedure based on the sensitivities of response forces is introduced to establish the identification equations of super-elements. Some principles are suggested on effective decomposing of the whole structure into super-elements for identification purposes. Numerical simulations are conducted at the end of this study. The numerical results show that all structural parameters can be identified using a relatively small number of transducers, and the computational time can also be greatly shortened.

关键词： numerical effective decomposing parameterization procedure divide-and-conquer ability time-domain identification

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Microenvironmental time-activity patterns in Chongqing, China

Yu ZHAO, Shuxiao WANG, Gangcai CHEN, Fei WANG, Kristin AUNAN, Jiming HAO

《环境科学与工程前沿（英文）》 2009年第3卷第2期页码 200-209 doi: 10.1007/s11783-009-0010-y

摘要： An investigation using recall questionnaires was conducted in winter and autumn 2006 to evaluate the time-activity patterns in Chongqing, China. The average time spent in seven microenvironments (MEs) including outdoors, transit, living room, bedroom, kitchen, classroom/office, and other indoors were found to be about 3.5, 1.1, 2.5, 9.7, 1.4, 4.2, and 1.7 h per day, respectively. According to the results of a nonparametric test, the sampling period and day of week were significant for the variation of the time spent in all MEs except for transit and outdoors. The time budget was analyzed using a general linear model (GLM), which exhibited significant variability by demographic factors such as gender, age, residence, education, and household income.

关键词： time-activity patterns microenvironment general linear model (GLM) Chongqing China