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Design and application of structural health monitoring system in long-span cable-membrane structure 预览
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作者 Tang Teng Yang Dong-Hui +2 位作者 Wang Lei Zhang Jian-Ren Yi Ting-Hua 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第2期461-474,共14页
Cable-membrane structures have small rigidity and are highly sensitive to wind. Structural health monitoring is necessary to ensure the serviceability and safety of the structure. In this research, the design method o... Cable-membrane structures have small rigidity and are highly sensitive to wind. Structural health monitoring is necessary to ensure the serviceability and safety of the structure. In this research, the design method of a structural health monitoring system is using the characteristics of a cable-membrane structure. Taking the Yueyang Sanhe Airport Terminal as an example, a finite element model is established to determine the critical structural components. Next, the engineering requirements and the framework of the monitoring system are studied based on the results of numerical analysis. The specific implementation of the structural health monitoring is then carried out, which includes sensor selection, installation and wiring. The proposed framework is successfully applied to the monitoring system for the Yueyang Airport terminal building, and the synchronous acquisition of fiber Bragg grating and acceleration sensor signals is implemented in an innovative way. The successful implementation and operation of structural health monitoring will help to guarantee the safety of the cablemembrane structure during its service life. 展开更多
关键词 cable-membrane STRUCTURAL HEALTH monitoring FI nite element model SYNCHRONOUS ACQUISITION STRUCTURAL safety
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Overreliance on Net Export and Investment Impedes China’s Structural Transformation: Estimation and Analysis Based on a Multi-Sector Growth Model 预览
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作者 渠慎宁 李鹏飞 吕铁 《中国经济学人:英文版》 2019年第3期44-65,共22页
Since reform and opening-up in 1978, changes in China’s industrial structure have generally followed the pattern of “Kuznets facts” but still exhibits some unique characteristics, which led us to raise the followin... Since reform and opening-up in 1978, changes in China’s industrial structure have generally followed the pattern of “Kuznets facts” but still exhibits some unique characteristics, which led us to raise the following three questions regarding China’s structural transformation:(1) Why did the share of China’s agricultural and manufacturing employment reduce/increase intermittently rather than continuously?(2) Why did the share of China’s agricultural employment increase during certain periods? When the share of manufacturing employment reduced, why did the workforce reversely flow into agriculture rather than move to the service sector?(3) Why did growth in the share of China’s service sector employment decelerate before reaching its peak? Why did the share of employment in the industrial sector suddenly increase after an abrupt decline? This paper creates a multisector economic growth model that contains non-homothetic preferences and differentiated productivity, and incorporates the “two drivers” therein for a demand-side estimation and analysis. The result shows that China’s economic growth model driven by net export and investment is a critical factor for explaining the three questions regarding its structural transformation. This paper believes that only by implementing supply-side structural reforms, reducing the dependence on net export and investment, and achieving sustainable endogenous economic growth will China be able to expedite its industrial restructuring. 展开更多
关键词 STRUCTURAL transformation net EXPORT and INVESTMENT multi-sector economic growth model supply-side STRUCTURAL REFORMS
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Hybrid Model Based on Wavelet Decomposition for Electricity Consumption Prediction 预览
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作者 夏晨霞 王子龙 黄春容 《东华大学学报:英文版》 EI CAS 2019年第1期77-87,共11页
The effective supply of electricity is the basis of ensuring economic development and people’s normal life. It is difficult to store electricity, as leading to the production and consumption must be completed simulta... The effective supply of electricity is the basis of ensuring economic development and people’s normal life. It is difficult to store electricity, as leading to the production and consumption must be completed simultaneously. Therefore, it is of great significance to accurately predict the demand for electricity consumption for the production planning of electricity and the normal operation of the society. In this paper, a hybrid model is constructed to predict the electricity consumption in China. The structural breaks test of monthly electricity consumption in China from January 2010 to December 2016 is carried out by using the structural breaks unit root test. Based on the existence of structura breaks, the electricity consumption data are decomposed into low-frequency and high-frequency components by wavelet model, and the separated low frequency signal and high frequency signal are predicted by autoregressive integrated moving average(ARIMA) and nonlinear autoregressive neural network(NAR), respectively. Therefore the wavelet-ARIMA-NAR hybrid model is constructed. In order to compare the effect of the hybrid model, the structural time series(STS) model is applied to predicting the electricity consumption. The results of prediction error test show that the hybrid model is more accurate for electricity consumption prediction. 展开更多
关键词 ELECTRICITY consumption forecasting WAVELET DECOMPOSITION STRUCTURAL BREAKS STRUCTURAL time series(STS) model
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Research on Cohesion and Coherence of Spoken Language—A Case of Desperate Housewives 预览
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作者 罗宇晓 《海外英语》 2019年第3期233-235,共3页
This paper mainly gives a research of cohesion and coherence in the spoken language.It takes one of the most popular teleplays—Desperate Housewives as its source of language data and tries to give a rather specific a... This paper mainly gives a research of cohesion and coherence in the spoken language.It takes one of the most popular teleplays—Desperate Housewives as its source of language data and tries to give a rather specific analysis of the application of the theory of cohesion and coherence.The paper mainly focuses on the structural cohesion and non-structural cohesion as well as the context of situation,which includes thematic structure,information structure,cohesive devices,transitivity,turn-taking,adjacency pair,etc.In addition,it encourages more people to pay attention to this theory and its application so as to make a little contribution to the development of discourse analysis. 展开更多
关键词 COHESION COHERENCE STRUCTURAL COHESION NON-STRUCTURAL COHESION
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Review on Cellulose Nanocrystal Assembly for Optical Applications 预览
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作者 Dong Li Na Feng +2 位作者 SiYuan Liu Lin Gan Jin Huang 《造纸与生物质材料:英文版》 2019年第2期54-62,共9页
Cellulose nanocrystals(CNCs)can self-assemble in suspension to form chiral cholesteric structure of liquid crystal with unique birefringence phenomena,and the structural parameters strongly depend upon the aspect rati... Cellulose nanocrystals(CNCs)can self-assemble in suspension to form chiral cholesteric structure of liquid crystal with unique birefringence phenomena,and the structural parameters strongly depend upon the aspect ratio,surface structure,and physicochemical properties of CNC,along with suspension media.Many attempts have been carried out to keep this cholesteric structure in solid state via removing solvent,such as slower solvent-evaporation,rapid vacuum-filtration,and spin-casting under centrifugal force.The solid-state iridescence of the cholesteric CNC arrays has been used as structural color,and showed a great potential for the coding and securing of optical information.Moreover,to promote practical applications of such structural iridescence,the cholesteric CNC arrays have been embedded into many kinds of substrates via in-situ reaction of monomers or physical blending with polymers.However,this kind of structural iridescences may lead to misreading information.The uniaxial-orientation assembly of CNC has thus been proposed via regulating external force fields of CNC self-assembly,and successfully achieved nanoparticle assembly-induced solid-state monochrome emission based on enhanced inelastic collision theory of CNC dipoles and photons.This method can eliminate the chiral arrangement of CNC and the corresponding iridescence,and the structural monochromaticity can contribute to enhancing the accuracy of optical information.Overall,the CNC can be controllably assembled as the ordered arrays in solid state and presented structural color,and support optical anti-counterfeiting strategies different from the fluorescent technologies. 展开更多
关键词 CELLULOSE nanocrystal SELF-ASSEMBLY STRUCTURAL adjustment STRUCTURAL COLOR OPTICAL applications
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Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany 预览
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作者 Felix Storch Gerald Kadler Jürgen Bauhus 《森林生态系统:英文版》 CSCD 2019年第3期249-260,共12页
Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest own... Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest owners and jurisdictions. At the same time, future harvesting intensity (HI) may increase to meet the demand for woody biomass by an increasing bioeconomy sector. Yet, the influence of HI on forest structural diversity is largely unknown. Here, we address this issue by analyzing the relationship between HI and structural diversity based on large-scale national forest inventory (NFI) data, where the latter is quantified using a previously developed Forest Structure Index and HI is expressed as wood volume removal during the period 2002-2012 for the same inventory plots. Results: Our results show a surprisingly small impact of harvesting intensity on changes in structural diversity for most of the analysed types of forests. Only intense harvesting (> 80%-90% of initial growing stock) led to a significant reduction in structural diversity. At low to moderate HI most aspects of structural diversity were positively influenced. Only the quadratic mean DBH and the volume of large trees (≥ 40 cm DBH) were substantially negatively influenced at HI > 60% and 70% of initial growing stock, respectively. Conclusions: In several forest types, HI could be increased without a reduction in overall structural diversity. Hence, structural diversity in these selectively managed forests appears to be a very resistant forest property in relation to HI. Other indicators at stand and landscape scale may be needed to adjust levels of HI that are suited to maintain forest biodiversity. 展开更多
关键词 Large-scale INVENTORY STRUCTURAL DIVERSITY index HARVESTING intensity Changes in STRUCTURAL DIVERSITY
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Piezoelectric Energy Analysis on Diverse Buoy Coupling with Hydrodynamic Parameters 预览
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作者 LIU Heng-xu LIU Ming +3 位作者 CHAI Yuan-chao SHU Guo-yang JING Feng-mei WANG Li-quan 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第3期279-287,共9页
This paper mainly describes the influence factors of the captured energy power by huge wave energy harvesters, in which the vertical motion of buoy can transform ocean’s potential energy into piezoelectric energy pow... This paper mainly describes the influence factors of the captured energy power by huge wave energy harvesters, in which the vertical motion of buoy can transform ocean’s potential energy into piezoelectric energy power by undulating waves. Firstly, related environmental coefficients are analyzed by means of the incident wave theory. Besides, the geometric structural parameters are also analyzed and compared under optimal environmental coefficients with semi-analytical solutions. Thirdly, the numerical results also show the impact trend of hydrodynamic parameters and geometric volume on motion, voltage and power with qualitative agreement. The numerical simulation confirms that the improved structure parameters could markedly deliver sufficient power under the same conditions with long-time stability. 展开更多
关键词 SEMI-ANALYTICAL method INCIDENT wave theory PIEZOELECTRIC CANTILEVER beam HYDRODYNAMIC characteristics lumped and structural parameters
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Hydrodynamic characteristics of 30%TBP/kerosene-HNO3 solution system in an annular centrifugal contactor 预览
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作者 Hong-Lin Chen Jian-Chen Wang +1 位作者 Wu-Hua Duan Jing Chen 《核技术:英文版》 SCIE CAS CSCD 2019年第6期16-27,共12页
Annular centrifugal contactors (ACCs) have many advantages and are recognized as key solvent-extraction equipment for the future reprocessing of spent nuclear fuel (RSNF). To successfully design and operate ACCs for R... Annular centrifugal contactors (ACCs) have many advantages and are recognized as key solvent-extraction equipment for the future reprocessing of spent nuclear fuel (RSNF). To successfully design and operate ACCs for RSNF, it is necessary to understand the hydrodynamic characteristics of the extraction systems in ACCs. The phase ratio (R = Vaq/Vorg, A/O) and liquid holdup volume (V) of the ACC are important hydrodynamic characteristics. In this study, a liquid-fast-separation method was used to systematically investigate the effects of the operational and structural parameters on the V and R (A/O) of a φ20 ACC by using a 30%TBP/kerosene- HNO3 solution system. The results showed that the operational and structural parameters had different effects on the V and R (A/O) of the mixing and separating zones of the ACC, respectively. For the most frequently used structural parameters of the φ20 ACC, when the rotor speed was 3500 r/min, the total flow rate was 2.0 L/h, and the flow ratio (A/O) was 1, the liquid holdup volumes in the mixing zone and rotor were 8.03 and 14.0 mL, respectively, and the phase ratios (A/O) of the mixing zone and separating zone were 0.96 and 1.43, respectively. 展开更多
关键词 ANNULAR CENTRIFUGAL CONTACTOR Liquid-fastseparation method Phase ratio (A/O) LIQUID HOLDUP volume Structural PARAMETER Operational PARAMETER
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Ionization behavior and dynamics of picosecond laser filamentation in sapphire 预览
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作者 Amina Lingfei Ji +1 位作者 Tianyang Yan Rui Ma 《光电进展(英文)》 2019年第8期9-15,共7页
Currently,laser-induced structural modifications in optical materials have been an active field of research.In this paper,we reported structural modifications in the bulk of sapphire due to picosecond(ps)laser filamen... Currently,laser-induced structural modifications in optical materials have been an active field of research.In this paper,we reported structural modifications in the bulk of sapphire due to picosecond(ps)laser filamentation and analyzed the ionization dynamics of the filamentation.Numerical simulations uncovered that the high-intensity ps laser pulses generate plasma through multi-photon and avalanche ionizations that leads to the creation of two distinct types of structural changes in the material.The experimental bulk modifications consist of a void like structures surrounded by cracks which are followed by a submicrometer filamentary track.By increasing laser energy,the length of the damage and filamentary track appeared to increase.In addition,the transverse diameter of the damage zone increased due to the electron plasma produced by avalanche ionizations,but no increase in the filamentary zone diameter was observed with increasing laser energy. 展开更多
关键词 structural modifications SAPPHIRE picosecond laser FILAMENTATION ionization dynamics
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Planned Disregard in Consumer Relations: A Proposition to Redress Consumer’s Lost Time 预览
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作者 Laís Bergstein 《美中法律评论:英文版》 2019年第4期133-142,共10页
Time exerts multiple influences on consumer relations since it is a triggering factor for several legal obligations, especially in long-term contractual bounds. The valuation of time as an essential and limited resour... Time exerts multiple influences on consumer relations since it is a triggering factor for several legal obligations, especially in long-term contractual bounds. The valuation of time as an essential and limited resource has emerged in the context of post-modernity with the formation of a new consciousness about the effects that its passage exerts on people. In Brazil, especially since 2009, several judicial decisions recognized the time lost by consumers trying to solve conflicts with suppliers as a special kind of moral damage and guaranteed the right to redress. However, many other consumers in similar situations had the same right denied in courts, mostly due to the lack of criteria to compensate the time lost due to acts attributable to suppliers. In this context, the research proposes a double criteria to pursue the adequate compensation for the time lost by consumer through the evaluation of supplier’s conducts. The study makes a distinction of consumer’s time and supplier’s time and defines the commercial practice entitled “planned disregard” as the abusive devaluation of time and the efforts made by consumers to achieve a successful conclusion to consumer contracts, mostly due to the lack of investments in efficient customer care services. This type of commercial practice violates the limits of good faith and represents an excessive advantage for the supplier, breaking the legal balance that the law establishes in consumer relations. The paper also approaches the legal duties of effective prevention and full redress of damages in Brazilian consumer law which are the legal tools to compensate the damage due to the loss of time suffered by consumers. Finally, it suggests how the members of the national consumer protection system, such as the regulatory agencies, civil entities, and the judiciary may contribute with structural processes to the prevention of undue loss of consumer time. 展开更多
关键词 consumer TIME PLANNED disregard damage DUE to TIME LOST full redress structural processes
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Advances in Computer Vision-Based Civil Infrastructure Inspection and Monitoring 预览
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作者 Billie F. Spencer Jr. Vedhus Hoskere Yasutaka Narazaki 《工程(英文)》 2019年第2期199-222,共24页
Computer vision techniques, in conjunction with acquisition through remote cameras and unmanned aerial vehicles (UAVs), offer promising non-contact solutions to civil infrastructure condition assessment. The ultimate ... Computer vision techniques, in conjunction with acquisition through remote cameras and unmanned aerial vehicles (UAVs), offer promising non-contact solutions to civil infrastructure condition assessment. The ultimate goal of such a system is to automatically and robustly convert the image or video data into actionable information. This paper provides an overview of recent advances in computer vision techniques as they apply to the problem of civil infrastructure condition assessment. In particular, relevant research in the fields of computer vision, machine learning, and structural engineering is presented. The work reviewed is classified into two types: inspection applications and monitoring applications. The inspection applications reviewed include identifying context such as structural components, characterizing local and global visible damage, and detecting changes from a reference image. The monitoring applications discussed include static measurement of strain and displacement, as well as dynamic measurement of displacement for modal analysis. Subsequently, some of the key challenges that persist toward the goal of automated vision-based civil infrastructure and monitoring are presented. The paper concludes with ongoing work aimed at addressing some of these stated challenges. 展开更多
关键词 Structural INSPECTION and MONITORING Artificial INTELLIGENCE Computer VISION Machine learning Optical flow
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The State of the Art of Data Science and Engineering in Structural Health Monitoring 预览
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作者 Yuequan Bao Zhicheng Chen +3 位作者 Shiyin Wei Yang Xu Zhiyi Tang Hui Li 《工程(英文)》 2019年第2期234-242,共9页
Structural health monitoring (SHM) is a multi-discipline field that involves the automatic sensing of structural loads and response by means of a large number of sensors and instruments, followed by a diagnosis of the... Structural health monitoring (SHM) is a multi-discipline field that involves the automatic sensing of structural loads and response by means of a large number of sensors and instruments, followed by a diagnosis of the structural health based on the collected data. Because an SHM system implemented into a structure automatically senses, evaluates, and warns about structural conditions in real time, massive data are a significant feature of SHM. The techniques related to massive data are referred to as data science and engineering, and include acquisition techniques, transition techniques, management techniques, and processing and mining algorithms for massive data. This paper provides a brief review of the state of the art of data science and engineering in SHM as investigated by these authors, and covers the compressive sampling-based data-acquisition algorithm, the anomaly data diagnosis approach using a deep learning algorithm, crack identification approaches using computer vision techniques, and condition assessment approaches for bridges using machine learning algorithms. Future trends are discussed in the conclusion. 展开更多
关键词 Structural HEALTH MONITORING MONITORING DATA COMPRESSIVE sampling Machine LEARNING DEEP LEARNING
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Structural model of substitutional sulfur in diamond
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作者 于洪雨 高楠 +6 位作者 李红东 黄旭日 段德芳 包括 朱明枫 刘冰冰 崔田 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第8期376-381,共6页
Based on ab initio calculations,it is found that the donor center of substitutional sulfur(S)in diamond with C2v symmetry is more stable than that with C3vsymmetry,which is different from previous reports in literatur... Based on ab initio calculations,it is found that the donor center of substitutional sulfur(S)in diamond with C2v symmetry is more stable than that with C3vsymmetry,which is different from previous reports in literature.The energy difference of C2vand C3vstructures is qualitatively affected by the supercell size,and the 216-atom supercell could be proposed as the minimum to obtain stable configuration of substitutional S in diamond.Using supercells of up to 512 atoms,the donor level of substitutional S with C2vsymmetry is deep. 展开更多
关键词 SUBSTITUTIONAL SULFUR in DIAMOND STRUCTURAL model MOLECULAR dynamic simulation SUPERCELL size
Structural stability and vibrational characteristics of CaB6 under high pressure
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作者 刘明坤 田灿 +4 位作者 黄晓丽 李芳菲 黄艳萍 刘冰冰 崔田 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期424-428,共5页
In situ Raman spectroscopy and x-ray diffraction measurements are used to explore the structural stability of CaB6 at high pressures and room temperature. The results show no evidence of structural phase transitions u... In situ Raman spectroscopy and x-ray diffraction measurements are used to explore the structural stability of CaB6 at high pressures and room temperature. The results show no evidence of structural phase transitions up to at least 40 GPa.The obtained equation of state with smooth pressure dependencies yields a zero-pressure isothermal bulk modulus B0=170(5) GPa, which agrees well with the previous measurements. The frequency shifts for A1g, Eg, and T2g vibrational modes of polycrystalline CaB6 are obtained with pressure uploading. As the pressure increases, all the vibration modes have smooth monotonic pressure dependence. The Gr¨uneisen parameter of Eg modes is the largest, indicating its largest dependence on the volume of a crystal lattice. 展开更多
关键词 CaB6 high PRESSURE DIAMOND ANVIL cell STRUCTURAL STABILITY
Domestication&Foreignization and structural shifts in the translation of Vandals in Open Secrets 预览
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作者 武仁莉 《校园英语》 2019年第2期229-231,共3页
On November 2013,the Chinese translation of Alice Munro’s short story series Open Secrets has been published by Yilin Press(gongkaidemimi,2013).Open secrets is one of Alice Munro,the winner of 2013 Nobel Prize in lit... On November 2013,the Chinese translation of Alice Munro’s short story series Open Secrets has been published by Yilin Press(gongkaidemimi,2013).Open secrets is one of Alice Munro,the winner of 2013 Nobel Prize in literature’s masterpiece.(goodreads,n.d).The literary value of the book was recognized by the whole world. 展开更多
关键词 DOMESTICATION & FOREIGNIZATION STRUCTURAL SHIFTS the TRANSLATION
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Deducing Complete Selection Rule Set for Driver Nodes to Guarantee Network's Structural Controllability 预览
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作者 Xichen Wang Yugeng Xi +1 位作者 Wenzhen Huang Shuai Jia 《自动化学报:英文版》 CSCD 2019年第5期1152-1165,共14页
Structural controllability is critical for operating and controlling large-scale complex networks. In real applications, for a given network, it is always desirable to have more selections for driver nodes which make ... Structural controllability is critical for operating and controlling large-scale complex networks. In real applications, for a given network, it is always desirable to have more selections for driver nodes which make the network structurally controllable. Different from the works in complex network field where structural controllability is often used to explore the emergence properties of complex networks at a macro level,in this paper, we investigate it for control design purpose at the application level and focus on describing and obtaining the solution space for all selections of driver nodes to guarantee structural controllability. In accord with practical applications,we define the complete selection rule set as the solution space which is composed of a series of selection rules expressed by intuitive algebraic forms. It explicitly indicates which nodes must be controlled and how many nodes need to be controlled in a node set and thus is particularly helpful for freely selecting driver nodes. Based on two algebraic criteria of structural controllability, we separately develop an input-connectivity algorithm and a relevancy algorithm to deduce selection rules for driver nodes. In order to reduce the computational complexity,we propose a pretreatment algorithm to reduce the scale of network's structural matrix efficiently, and a rearrangement algorithm to partition the matrix into several smaller ones. A general procedure is proposed to get the complete selection rule set for driver nodes which guarantee network's structural controllability. Simulation tests with efficiency analysis of the proposed algorithms are given and the result of applying the proposed procedure to some real networks is also shown, and these all indicate the validity of the proposed procedure. 展开更多
关键词 ALGEBRAIC criteria COMPLETE SELECTION rule set structural CONTROLLABILITY DRIVER NODES
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Structure Optimization for Echo State Network Based on Contribution
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作者 Dingyuan Li Fu Liu +1 位作者 Junfei Qiao Rong Li 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第1期97-105,共9页
Echo State Network (ESN)is a recurrent neural network with a large,randomly generated recurrent part called the dynamic reservoir.Only the output weights are modified during training.However,proper balancing of the tr... Echo State Network (ESN)is a recurrent neural network with a large,randomly generated recurrent part called the dynamic reservoir.Only the output weights are modified during training.However,proper balancing of the trade-off between the structure and performance for ESN remains a difficult task.In this paper,a structure optimized method for ESN based on contribution is proposed to simplify its network structure and improve its performance. First,we evaluate the contribution of reservoir neurons.Second,we present a pruning mechanism to remove the unimportant connection weights of reservoir neurons with low contribution.Finally,the new output weights are learned with the pseudo inverse method.The novel optimized ESN,named C-ESN,is tested on a Lorenz chaotic time-series prediction and an actual municipal sewage treatment system.The simulation results show that the C-ESN can have better prediction and generalization performance than ESN. 展开更多
关键词 NEURAL NETWORK STRUCTURAL DESIGN time-series PREDICTION
Widefield optical coherence tomography of foveal dragging in retinopathy of prematurity
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作者 Victor M.Villegas Stephen G.Schwartz +2 位作者 Audina M.Berrocal Timothy G.Murray Harry W. Flynn Jr. 《国际眼科杂志:英文版》 SCIE CAS 2019年第7期1219-1223,共5页
Dear Editor,Despite substantial advances in neonatal medicine, retinopathy of prematurity (ROP) continues to be a serious therapeutic challenge⑴.Visual acuity loss in patients with ROP has been associated with struct... Dear Editor,Despite substantial advances in neonatal medicine, retinopathy of prematurity (ROP) continues to be a serious therapeutic challenge⑴.Visual acuity loss in patients with ROP has been associated with structural retinal abnormalities (including retinal detachment, retinal folds, and pigmentary retinopathy), cataract, glaucoma, and amblyopia due to refractive error or strabismus[2]. 展开更多
关键词 RETINOPATHY of prematurity(ROP) foveal DRAGGING structural RETINAL ABNORMALITIES
Wide bandwidth acoustic transmission via coiled-up metamaterial with impedance matching layers
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作者 Xiao Jia Yang Li +2 位作者 Yinghao Zhou Minghui Hong Ming Yan 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第6期37-44,共8页
Many acoustic metamaterials suffer from a narrow bandwidth transmission because of the impedance mismatch at the airmetamaterial interface. In this paper, a two-dimensional impedance-matched metamaterial with broadban... Many acoustic metamaterials suffer from a narrow bandwidth transmission because of the impedance mismatch at the airmetamaterial interface. In this paper, a two-dimensional impedance-matched metamaterial with broadband transmission performance is investigated. The impedance matching layer is introduced for a gradient variation of effective impedance from the inlet of the unit to the outlet. The effective medium theory and corresponding effective model are used to explain the underlying mechanism. The improved energy transmission of our designs is demonstrated by experiment and numerical simulation within a broad frequency bandwidth over 6 kHz. Our impedance-matched design can be used to enhance sound absorption, which is expected to present improved acoustic performance in the applications of acoustic damper and muffler. 展开更多
关键词 general linear ACOUSTICS structural ACOUSTICS and vibration acoustical measurements and INSTRUMENTATION wavestructure INTERACTIONS
The Tesistan, Mexico earthquake (Mw 4.9) of 11 May 2016: seismictectonic environment and resonance vulnerability on buildings 预览
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作者 Alejandro Ramírez-Gaytán Adolfo Preciado +3 位作者 William L. Bandy Edilson F. Salazar-Monroy Miguel A. Jaimes Leonardo Alcantara 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第3期579-595,共17页
To highlight the importance of small earthquakes in seismic hazard, a study of the 11 May 2016, Mw 4.9, Tesistan, Mexico earthquake is presented. Due to the close proximity of the event to the city, accelerations were... To highlight the importance of small earthquakes in seismic hazard, a study of the 11 May 2016, Mw 4.9, Tesistan, Mexico earthquake is presented. Due to the close proximity of the event to the city, accelerations were considerably higher than those caused by historical severe earthquakes (6.0 < Mw < 8.2). This paper addresses two objectives related to the Tesistan event: the fi rst is to estimate the focal mechanism solution in order to place the event in the context of the tectonic environment of this area. The second is focused on a vulnerability evaluation of buildings that suff ered resonance. Several building′s typologies with variations in construction system and height are assessed in terms of resonance with the structural and soil periods. The results show that around the Zapopan station, strong damage is expected in intermediate to high-rise buildings (12-30 m) with moment resistant frame systems and in reinforced concrete shear walls. Masonry structures around this station may not present resonance. In contrast, in the surroundings of the Guadalajara station, all intermediate height buildings from 9 to 21 m may present resonance. 展开更多
关键词 Tesistan EARTHQUAKE SEISMICITY of Guadalajara site eff ECTS structural VULNERABILITY
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