检索结果-南通市图书馆

An attention-based deep learning model for citywide traffic flow forecasting

International Journal of Digital Earth 2022年第1期15卷 323-344页

作者： Tao Zhou Bo Huang Rongrong Li Xiaoqian Liu Zhihui Huang Department of Surveying and Geoinformatics Faculty of Geosciences and Environmental EngineeringSouthwest Jiaotong University (SWJTU)ChengduPeople’s Republic of China Department of Geography and Resource Management The Chinese University of Hong KongHong KongPeople’s Republic of China Institute of Space and Earth Information Science The Chinese University of Hong KongHong KongPeople’s Republic of China

Prompt and accurate traffic flow forecasting is a key foundation of urban traffic management.However,the flows in different areas and feature channels(inflow/outflow)may correspond to different degrees of importance in forecasting flows.Many forecasting models inadequately consider this heterogeneity,resulting in decreased predictive accuracy.To overcome this problem,an attention-based hybrid spatiotemporal residual model assisted by spatial and channel information is proposed in this study.By assigning different weights(attention levels)to different regions,the spatial attention module selects relatively important locations from all inputs in the modeling process.Similarly,the channel attention module selects relatively important channels from the multichannel feature map in the modeling process by assigning different weights.The proposed model provides effective selection and attention results for key areas and channels,respectively,during the forecasting process,thereby decreasing the computational overhead and increasing the accuracy.In the case involving Beijing,the proposed model exhibits a 3.7%lower prediction error,and its runtime is 60.9%less the model without attention,indicating that the spatial and channel attention modules are instrumental in increasing the forecasting efficiency.Moreover,in the case involving Shanghai,the proposed model outperforms other models in terms of generalizability and practicality.

关键词： Attention mechanism long short-term memory model residual network spatiotemporal forecasting traffic flow

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy-efficient firing modes of chay neuron model in different bursting kinetics

引用

Science China(Technological Sciences) 2022年第8期65卷 1661-1674页

作者： LU LuLu YI Ming liu xiaoqian School of Mathematics and Physics China University of GeosciencesWuhan 430074China

The firing sequence of the neuron system that transmits information consumes a significant amount of energy, but it is unclear how the firing pattern of the neuron system determines its energy efficiency. The mode transformation and energy efficiency in different firing modes are investigated using the Chay neuron model. It has been found that when system parameters are tuned,the neurons show complex bursting kinetics. The period-n bursting state of the neuron carries high amounts of information while consuming less energy per unit of information, resulting in higher energy efficiency. In particular, the mixed discharge state,where the neuron is in several bursting states simultaneously, is more energy efficient, and appropriate electromagnetic inductioncan enhance the neuron's energy efficiency. Furthermore, there are optimal system parameters that maximize the energy efficiency of firing modes, demonstrating that the neuron carries high amounts of information while consuming less energy per unit of information. The study helps to understand the energy mechanism of neural information propagation and provides an insight into the energy efficiency characteristic of neuron systems.

关键词： energy efficiency firing modes bursting kinetics electromagnetic induction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of temperature on Lu’an bituminous char structure evolution in pyrolysis and combustion

引用

Frontiers in Energy 2021年第1期15卷 14-25页

作者： Yandi ZHANG Yinhe liu Xiaoli DUAN Yao ZHOU Xiaoqian Liu Shijin XU State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In the process of pyrolysis and combustion of coal particles, coal structure evolution will be affected by the ash behavior, which will further affect the char reactivity, especially in the ash melting temperature zone. Lu’an bituminous char and ash samples were prepared at the N_(2) and air atmospheres respectively across ash melting temperature. A scanning electron microscope (SEM) was used to observe the morphology of char and ash. The specific surface area (SSA) analyzer and thermogravimetric analyzer were respectively adopted to obtain the pore structure characteristics of the coal chars and combustion parameters. Besides, an X-ray diffractometer (XRD) was applied to investigate the graphitization degree of coal chars prepared at different pyrolysis temperatures. The SEM results indicated that the number density and physical dimension of ash spheres exuded from the char particles both gradually increased with the increasing temperature, thus the coalescence of ash spheres could be observed obviously above 1100℃. Some flocculent materials appeared on the surface of the char particles at 1300℃, and it could be speculated that β-Si_(3)N_(4) was generated in the pyrolysis process under N_(2). The SSA of the chars decreased with the increasing pyrolysis temperature. Inside the char particles, the micropore area and its proportion in the SSA also declined as the pyrolysis temperature increased. Furthermore, the constantly increasing pyrolysis temperature also caused the reactivity of char decrease, which is consistent with the results obtained by XRD. The higher combustion temperature resulted in the lower porosity and more fragments of the ash.

关键词： bituminous char pyrolysis ash structure evolution reactivity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A survey of visual analytics techniques for online education

引用

Visual Informatics 2022年第4期6卷 67-77页

作者： Xiaoyan Kui Naiming liu Qiang liu Jingwei liu xiaoqian Zeng Chao Zhang School of Computer Science Central South University932 Lushan South RoadChangsha410083HunanChina

Visual analytics techniques are widely utilized to facilitate the exploration of online educational data.To help researchers better understand the necessity and the efficiency of these techniques in online education,we systematically review related works of the past decade to provide a comprehensive view of the use of visualization in online education problems.We establish a taxonomy based on the analysis goal and classify the existing visual analytics techniques into four categories:learning behavior analysis,learning content analysis,analysis of interactions among students,and prediction and recommendation.The use of visual analytics techniques is summarized in each category to show their benefits in different analysis tasks.At last,we discuss the future research opportunities and challenges in the utilization of visual analytics techniques for online education.

关键词： Visual analytics Online education Behavior analysis Content analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Marine target detection based on Marine-Faster R-CNN for navigation radar plane position indicator images

引用

Frontiers of Information Technology & Electronic Engineering 2022年第4期23卷 630-643页

作者： Xiaolong CHEN xiaoqian MU Jian GUAN Ningbo liu Wei ZHOU Marine Target Detection Research Group Naval Aviation UniversityYantai264001China

As a classic deep learning target detection algorithm,Faster R-CNN(region convolutional neural network)has been widely used in high-resolution synthetic aperture radar(SAR)and inverse SAR(ISAR)image detection.However,for most common low-resolution radar plane position indicator(PPI)images,it is difficult to achieve good performance.In this paper,taking navigation radar PPI images as an example,a marine target detection method based on the Marine-Faster R-CNN algorithm is proposed in the case of complex background(e.g.,sea clutter)and target characteristics.The method performs feature extraction and target recognition on PPI images generated by radar echoes with the convolutional neural network(CNN).First,to improve the accuracy of detecting marine targets and reduce the false alarm rate,Faster R-CNN was optimized as the Marine-Faster R-CNN in five respects:new backbone network,anchor size,dense target detection,data sample balance,and scale normalization.Then,JRC(Japan Radio Co.,Ltd.)navigation radar was used to collect echo data under different conditions to build a marine target dataset.Finally,comparisons with the classic Faster R-CNN method and the constant false alarm rate(CFAR)algorithm proved that the proposed method is more accurate and robust,has stronger generalization ability,and can be applied to the detection of marine targets for navigation radar.Its performance was tested with datasets from different observation conditions(sea states,radar parameters,and different targets).

关键词： Marine target detection Navigation radar Plane position indicator(PPI)images Convolutional neural network(CNN) Faster R-CNN(region convolutional neural network)method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Memory characteristics of microcavity dielectric barrier discharge

引用

Journal of Semiconductors 2018年第11期39卷 62-67页

作者： Yanzhou Sun Xiaoqian Liu Dati Su Huibin Yang School of Electrical Engineering and Automation Henan Polytechnic University

The nonlinear resistance characteristics of microcavity dielectric barrier discharge are mainly studied in the paper. A simulation model of microcavity dielectric barrier discharge is herein built to study the relationship between voltage and current in the process of discharge, and thus its I–V characteristic curve can be obtained. The I–V characteristics of the memristor are analyzed and compared with the I–V characteristics of the dielectric barrier discharge; it can be found that the I–V characteristics of the microcavity dielectric barrier discharge are similar to the characteristics of the memristor by analyzing them. The memory characteristics of microcavity dielectric barrier discharge are further analyzed.

关键词： microcavity dielectric barrier discharge memristor I-V characteristic memory characteristics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Can the low-carbon city pilot policy promote the upgrading of high-carbon emitting enterprises? Evidence from China

引用

Chinese Journal of Population,Resources and Environment 2022年第3期20卷 217-226页

作者： Chang’an Wang Kun Lin Xiaoqian Liu School of Economics Southwestern University of Finance and EconomicsChengdu611130China School of International Business Southwestern University of Finance and EconomicsChengdu611130China Research Institute of Economics and Management Southwestern University of Finance and EconomicsChengdu611130China

As a crucial environmental reform system to realize“carbon peaking”and“carbon neutrality”,the pilot policy of low-carbon cities(LCCs)puts pressure and challenges on high-carbon emitting enterprises(HCEEs)while providing opportunities for these firms to take the path of independent transformation.Employing the data of Chinese listed enterprises from 2006 to 2016 and adopting a difference-in-differences(DID)model,we evaluated the impact of LCC construction on the upgrading of HCEEs and its mechanisms.The results indicate that LCC construction enhances the upgrading of HCEEs in the pilot cities.The conclusions remain stable after a series of robustness tests.The mechanism analysis reveals that LCC construction triggers the upgrading of HCEEs by promoting resource allocation efficiency,R&D investment,and green technology innovation.The heterogeneity results indicate that this positive effect is more pronounced for HCEEs in regions with more stringent environmental law enforcement.This study also observes that the upgrading impact is more promi‐nent for state-owned enterprises,enterprises with higher bargaining power,and enterprises whose managers have a long-term vision.The above results provide directions for upgrading HCEEs and replicable evidence for cities in developing economies to fulfill the win-win target of environmental protection and economic transfor‐mation.

关键词： Low-carbon city pilot policy High-carbon emitting enterprises Enterprise upgrading Green technology innovation Resource allocation efficiency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mesoscale structures and mechanisms in ionic liquids

引用

Particuology 2020年第1期18卷 55-64页

作者： Xiaomin liu xiaoqian Yao Yanlei Wang Suojiang Zhang School of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071ShandongChina Beijing Key Laboratory of Ionic Liquids Clean Process State Key Laboratory of Multiphase Complex SystemsKey Laboratory of Green Process and EngineeringInstitute of process EngineeringChinese Academy of SciencesBeijing 100190China

Ionic liquids(ILs)have attracted intensive attention and have been used widely in many applications because of their diversified properties,which are caused by the special structure of the ILs.Ionic clusters are one of the typical structures that exist widely in the IL system.They are stable under certain conditions and change under other conditions.Ionic clusters are a typical mesoscale phenomenon in mesoscience.In this review,we summarize our recent progress related to ionic clusters,including the ionic-cluster structure,changing mechanisms,and their effect on the physicochemical properties.IL cluster investigation based on mesoscience is very important,will provide new insight into the structures and properties of ILs,and will boost further exploration of IL applications.

关键词： Ionic liquid Mesoscale structure Ionic cluster

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparative study on mode split discrete choice models

引用

Journal of Modern Transportation 2013年第4期21卷 266-272页

作者： Xianlong Chen Xiaoqian Liu Fazhi Li Guangzhou Transport Planning and Research Institute Transportation Planning and Design Division Architectural Design&Research Institute of Tongji University(Group) Co.Ltd.

Discrete choice model acts as one of the most important tools for studies involving mode split in the context of transport demand forecast. As different types of discrete choice models display their merits and restrictions diversely, how to properly select the specific type among discrete choice models for realistic application still remains to be a tough problem. In this article, five typical discrete choice models for transport mode split are, respectively, discussed, which includes multinomial logit model, nested logit model （NL）, heteroscedastic extreme value model, multinominal probit model and mixed multinomial logit model （MMNL）. The theoretical basis and application attributes of these five models are especially analysed with great attention, and they are also applied to a realistic intercity case of mode split forecast, which results indi- cating that NL model does well in accommodating similarity and heterogeneity across alternatives, while MMNL model serves as the most effective method for mode choice prediction since it shows the highest reliability with the least significant prediction errors and even outperforms the other four models in solving the heterogeneity and similarity problems. This study indicates that conclusions derived from a single discrete choice model are not reliable, and it is better to choose the proper model based on its characteristics.

关键词： Discrete choice model Mode split NL MMNL HEV MNP

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Photolabile Protecting Group-Mediated Synthesis of 2-Deoxy-Glycosides

引用

Chinese Journal of Chemistry 2021年第12期39卷 3309-3314页

作者： xiaoqian Li Zhi Ma Rongkun liu Mattan Hurevich You Yang Shanghai Key Laboratory of New Drug Design Engineering Research Center of Pharmaceutical Process ChemistryMinistry of EducationSchool of PharmacyEast China University of Science and Technology130 Meilong RoadShanghai 200237China Institute of Chemistry Safra CampusGivat RamHebrew University of Jerusalem91904Israel

A green and efficient photolabile protecting group(PPG)-mediated glycosidation approach for the synthesis of 2-deoxy-glycosides is reported.By employing ortho-nitrobenzyl carbonate(oNBC)as PPG,N,N-dimethylformamide(DMF)-modulated SPhosAuNTf_(2)-promoted glycosidation with per-oNBC-protected 2-deoxy-glycosyl ynenoates affords the 2-deoxy-glycosides with moderate to excellentα-selectivities presumably depending on the reactivities of the acceptor alcohols.Based on the PPG-mediated glycosidation approach,oligosaccharides with three to six oNBC groups are effectively achieved.The multiple oNBC groups in the 2-deoxy-glycosides are completely cleaved by irradiation at 365 nm,resulting in the desired 2-deoxy-glycosides in an efficient manner without affecting the common alkyne,alkene,azide functional groups and the traditional protecting groups on the aglycones.

关键词： Glycosides Glycosylation Protecting groups Gold Glycosyl ynenoates

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：