检索结果-南通市图书馆

Social media as passive geo-participation in transportation planning-how effective are topic modeling&sentiment analysis in comparison with citizen surveys?

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2020年第4期23卷 275-292页

作者： Oliver Lock christopher Pettit City Futures Research Centre Faculty of Built EnvironmentUniversity of New South Wales(UNSW)SydneyAustralia Expanded Perception and Interaction Centre(Epicentre) Faculty of Art&DesignUniversity of New South Wales(UNSW)SydneyAustralia

We live in an era of rapid urbanization as many cities are experiencing an unprecedented rate of population growth and *** transport is playing an increasingly important role in urban mobility with a need to move people and goods efficiently around the *** such pressures on existing public transportation systems,this paper investigates the opportunities to use social media to more effectively engage with citizens and customers using such *** research forms a case study of the use of passively collected forms of big data in cities-focusing on Sydney,***,it examines social media data(Tweets)related to public transport ***,it joins this to longitudinal big data-delay information continuously broadcast by the network over a year,thus forming hundreds of millions of data ***,tones,and sentiment are modeled using machine learning and Natural Language Processing(NLP)*** resulting data,and models,are compared to opinions derived from a citizen survey among *** validity of such data and models versus the intentions of users,in the context of systems that monitor and improve transport performance,are *** such,key recommendations for developing Smart Cities were formed in an applied research context based on these data and techniques.

关键词： Social media smart cities public participation urban sensing transport planning natural language processing machine learning big data

Numerical analysis for the prediction of bump prone conditions:A southern Appalachian pillar coal bump case study

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

International Journal of Mining Science and Technology 2021年第1期31卷 75-81页

作者： christopher Newman David Newman Appalachian Mining&Engineering Inc.LexingtonKY 40503USA

Two miners were fatally injured when a pillar bump occurred during retreat mining in a southern West Virginia coal *** mine was operating in the Eagle seam with overmining in the No.2 Gas and Powellton seams.A coal bump is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the *** significant strides have been made by academia,industry,and regulatory agencies to better understand bump conditions and mitigation techniques,coal bumps represent a long standing,highly site-specific engineering problem in which the exact failure mechanism is not clearly *** this case history,a cut-by-cut analysis of retreat mining operations was conducted on the 4 East Main leading up to the pillar bump *** input parameters were derived from site-specific geologic information and mine geometry for the analysis of pillar stress conditions and energy release using *** overview of stress conditions in the panel was presented including a precursor event that occurred two crosscuts inby the bump *** methodology presented in the paper for the evaluation of the fatal bump event can be used for the identification of bump prone conditions prior to development and retreat of a mining area.

关键词： Bump Burst Coal Energy release rate LaModel Numerical modeling

The International Union of Pure and Applied Chemistry and its role on the world stage

在线全文

学校读者我要写书评

暂无评论

National Science Review 2021年第5期8卷 11-12页

作者： christopher Brett Department of Chemistry University of Coimbra IUPAC

It is a pleasure to write this contribution for National Science Review and to share information about the different pathways being followed by the International Union of Pure and Applied Chemistry (IUPAC) toward a worldwide sustainable *** was founded in 1919 with a strong impetus from chemical industries that recognized the importance of using a common language, particularly for chemical compounds,

关键词：

Tessellations in GIS:Part I—putting it all together

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2016年第1期19卷 9-25页

作者： christopher Gold Faculty of Computing Engineering and ScienceUniversity of South WalesWalesUK Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengduChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing(LIESMARS)Wuhan UniversityWuhanChina

This article attempts to describe the role of tessellated models of space within the discipline of geographic information systems(GIS)—a speciality coming largely out of geography and land surveying,where there was a strong need to represent information about the land’s surface within a computer system rather than on the original paper *** look at some of the basic operations in GIS,including dynamic and kinetic *** examine issues of topology and data structures and produce a tessellation model that may be widely applied both to traditional“object”and“field”data *** on this framework,it can be argued that tessellation models are fundamental to our understanding and processing of geographical space,and provide a coherent framework for understanding the“space”in which we *** first article examines static structures,and a subsequent article looks at“change”—what happens when things move.

关键词： GIS tessellation model static structure topology data structure object and field Voronoi diagram

Science of empirical design in mining ground control

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

International Journal of Mining Science and Technology 2016年第3期26卷 461-470页

作者： Mark christopher MSHA Pittsburgh Safety & Health Technology Center

Many problems in rock engineering are limited by our imperfect knowledge of the material properties and failure mechanics of rock masses. Mining problems are somewhat unique, however, in that plenty of real world experience is generally available and can be turned into valuable experimental *** pillar that is developed, or stope that is mined, represents a full-scale test of a rock mechanics design. By harvesting these data, and then using the appropriate statistical techniques to interpret them,mining engineers have developed powerful design techniques that are widely used around the *** empirical methods are readily accepted because they are simple, transparent, practical, and firmly tethered to reality. The author has been intimately associated with empirical design for his entire career, but his previous publications have described the application of individual techniques to specific problems. The focus of this paper is the process used to develop a successful empirical method. A sixstage process is described: identification of the problem, and of the end users of the final product; development of a conceptual rock mechanics model, and identification of the key parameters in that model;identification of measures for each of the key parameters, and the development of new measures(such as rating scales) where necessary; data sources and data collection; statistical analysis; and packaging of the final product. Each of these stages has its own potential rewards and pitfalls, which will be illustrated by incidents from the author's own experience. The ultimate goal of this paper is to provide a new and deeper appreciation for empirical techniques, as well as some guidelines and opportunities for future developers.

关键词： Design Pillar Stope Empirical Statistics Modeling

With the wizard of the unit circle-An appreciation of ***

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第6期31卷 1085-1088页

作者： christopher Earls Brennen Richard and Dorothy Hayman Professor of Mechanical Engineering EmeritusCalifornia Institute of TechnologyPasadenaCalifornia 91125

An account of my interactions with *** Yao-tsu Wu of the California Institute of Technology.

关键词： Caltech fluid mechanics cavitation

Unanticipated multiple seam stresses from pillar systems behaving as pseudo gob–case histories

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

International Journal of Mining Science and Technology 2017年第1期27卷 131-137页

作者： Gauna Michael Mark christopher Pittsburgh Safety and Health Technology Center Mine Safety and Health Administration(MSHA)PittsburghPA 15236USA

Underground coal mining in the U.S. is conducted in numerous regions where previous workings exist above and/or below an actively mined seam. Miners know that overlying or underlying fully extracted coal areas, also known as gob regions, can result in abutment stresses that affect the active mining. If there was no full extraction, and the past mining consists entirely of intact pillars, the stresses on the active seam are usually minimal. However, experience has shown that in some situations there has been sufficient yielding in overlying or underlying pillar systems to cause stress transfer to the adjoining larger pillars or barriers, which in turn, transfer significant stresses onto the workings of the active seam. In other words, the overlying or underlying pillar system behaves as a ‘‘pseudo gob." The presence of a pseudo gob is often unexpected, and the consequences can be severe. This paper presents several case histories, summarized briefly below, that illustrate pseudo gob phenomenon:(1) pillar rib degradation at a West Virginia mine at 335 m depth that contributed to a rib roll fatality,(2) pillar rib deterioration at a Western Kentucky mine at 175 m depth that required pillar size adjustment and installation of supplemental bolting,(3) roof deterioration at an eastern Kentucky mine at 400 m depth that stopped mine advance and required redirecting the section development,(4) coal burst on development at an eastern Kentucky mine at 520 m depth that had no nearby pillar recovery, and(5) coal burst on development at a West Virginia mine at the relatively shallow depth of 335 m that also had no nearby pillar recovery. The paper provides guidance so that when an operation encounters a potential pseudo gob stress interaction the hazard can be mitigated based on an understanding of the mechanism encountered.

关键词： Underground mining Coal Multiple seam Gob Ground control

Biological and cultural diversity in the context of botanic garden conservation strategies

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2017年第6期39卷 396-401页

作者： christopher P.Dunn Cornell Botanic Gardens 124 Comstock Knoll Drive Cornell University

Impacts of global climate change, habitat loss, and other environmental changes on the world's biota and peoples continue to increase, especially on islands and in high elevation areas. Just as floristic diversity is affected by environmental change, so too are cultural and linguistic diversity. Of the approximately 7000 extant languages in the world, fully 50% are considered to be at risk of extinction, which is considerably higher than most estimates of extinction risks to plants and animals. To maintain the integrity of plant life, it is not enough for botanic gardens to consider solely the effects of environmental change on plants within the context of major conservation strategies such as the Global Strategy for Plant Conservation and the Convention on Biological Diversity. Rather, botanic gardens should actively engage in understanding and communicating the broader impacts of environmental change to biological and cultural diversity.

关键词： Biocultural diversity Botanic gardens Linguistic diversity Plant diversity

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

在线全文

学校读者我要写书评

暂无评论

航空动力学报 2007年第5期22卷 683-693页

作者： christopher Long Peter Childs TFMRC Department of Engineering and Design University of Sussex Brighton BN1 9QT UK

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig. Measurements of heat transfer from the discs and tangential velocities are presented. The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine. Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air. Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows (Reφup to 5×106 and ReΦup to 2×105).Two different builds have been tested. The most significant difference between these two build configurations is the size of the annular gap between the (non-rotating) drive shaft and the bores of the discs. The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method. The velocity measurements were made using a two component, LDA system. The heat transfer results from the discs show differences between the two builds. This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity. There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig. For the narrow annular gap, there is an increase of non-dimensional tangential velocity Vφ/Ωr with radial location to solid body rotation Vφ/Ωr=*** the wider annular gap, the non-dimensional velocities show a decrease with radial location to solid body rotation.

关键词：轴向直流热转移旋转式孔进口接头