基于网格热度值的船舶规律路径提取算法

随着无线传感器、卫星、GPS(global positioning system)等移动目标定位技术的发展,产生的移动数据(诸如人类足迹、车辆行驶轨迹和船舶轨迹等)的规模越来越大.而移动目标检测设备只会存储一系列离散点的信息,所以基于离散点来追踪和恢复其完整的轨迹是更加全面掌握移动目标运动规律的必要前提.数据挖掘方法能从移动目标的历史位置信息中挖掘出"规律"路径,其中基于网格的聚类分析方法不仅能有效表达这些轨迹点,还能分析出这些轨迹点之间的关系,是提取规律路径的有效方法.为此,提出了基于网格"热度值"的距离和密度相结合的热度因子相似性度量方法,进而给出了移动目标规律路径提取算法.最后,使用船舶自动识别系统(automatic identification system,AIS)生成的船舶实际动态数据进行测试,来验证该算法的精度和性能.算法分析和实验结果表明:基于网格热度值的规律路径提取算法能有效地发现不同形状的轨迹序列.

基于关键词热度分析的我国原发性骨质疏松相关中医药研究热点及趋势评述

目的对1987-2017年公开发表的原发性骨质疏松相关中医药文献的关键词进行定量分析,以期探索研究热点与研究趋势的变化规律。方法检索万方、CNKI、维普数据库,运用描述性统计方法分析关键词热值。结果检索出6 324篇文献,筛选后剩余2 679篇,文献的总体趋势是波浪式上升的。高热关键词共有21个,可分为三类:主要以大鼠为实验对象的实验研究、主要以老年人为研究对象的临床研究、以补肾为主的中药治疗,研究热点涵盖范围较广并具有明显的阶段性,但关键词及名词术语的规范性不足,缺少数据挖掘相关的研究。结论随着我国人口的快速老龄化,未来原发性骨质疏松相关中医药相关研究需求趋于增大。数据挖掘相关研究未来应成为其研究热点,中医药研究相关关键词及名词术语亟须规范。

微博热度研究现状及未来发展方向

微博热度是目前关于微博的热门研究领域之一,主要包括热门话题发现和微博热度预测2个部分,进行微博热度研究对舆情监控、微博营销、个性化推荐具有重要意义。从话题发现和热度预测2个方面对微博热度研究现状展开综述,总结了目前微博热度领域的研究现状和成果,归纳了已有研究的不足,探寻未来可以进行深入研究和改进的方向。

基于特定用户角色的热度计算方法及应用

针对现有热度值计算方法计算结果不准确的问题,提出一种改进的热度值计算方法。在综合考虑发布者、关注度、时间、转发数和评论数等因素的前提下,通过设置个人认证用户和非个人认证用户等特定用户的权重来计算话题的热度,对热度值计算公式进行改进。实验结果表明,该方法能够有效对微博热点话题进行检测,实现对微博热点事件的监控和管理。

基于熵值的网络论坛热点话题发现

针对网络论坛热点话题的识别、发现和舆情监测问题,提出一种基于热度熵值的热点话题发现方法。通过网络爬虫抓取网络论坛中的数据,在对数据进行预处理和分析热点话题属性特征的基础上,合理定义各属性的权重和话题的热度熵值,并以此对话题的热点信息进行分析、统计与评估,从而发现和追踪网络论坛中的热点话题。同时,对话题的热度进行细致划分和各种类型的定义,采用不同阈值策略计算不同类型的热度信息标注的准确率。实验结果表明,该方法合理、有效,相比于传统的话题语义分析方法具有较高的准确率,可作为互联网论坛舆情监测的依据。

Operation optimization of prefabricated light modular radiant heating system:Thermal resistance analysis and numerical study

The utilization of prefabricated light modular radiant heating system has demonstrated significant increases in heat transfer efficiency and energy conservation capabilities.Within prefabricated building construction,this new heating method presents an opportunity for the development of comprehensive facilities.The parameters for evaluating the effectiveness of such a system are the upper surface layer’s heat flux and temperature.In this paper,thermal resistance analysis calculation based on a simplified model for this unique radiant heating system analysis is presented with the heat transfer mechanism’s evaluation.The results obtained from thermal resistance analysis calculation and numerical simulation indicate that the thermal resistance analysis method is highly accurate with temperature discrepancies ranging from 0.44℃ to−0.44℃ and a heat flux discrepancy of less than 7.54%,which can meet the requirements of practical engineering applications,suggesting a foundation for the prefabricated radiant heating system.

长征数据三维可视化分析平台设计与实现

为用好长征教育资源,引导群众在实践中培育爱国情怀,以长征革命历史为背景,结合大数据三维可视化技术,推出“长征数据三维可视化分析平台”,以大数据三维可视化、云计算赋能长征精神学习,多维度立体展现长征这段历史,激发爱国热情,传承爱国基因。该项目采用Spring Boot框架,整合MyBatis及Thymeleaf模板引擎构建系统架构,使用Maven项目管理工具,通过爬虫技术完成数据采集,依据牛顿冷却定律,提出了“访问量+时间衰减”文章热度值算法,前端展示使用HTML+CSS+JS及ECharts、Highcharts图表以及JS代码库JQuery,实现了三维长征路线、实景展示(VR)、祭扫景点等功能。

数据挖掘的网络热点话题演化动态预测

为了及时发现网络热点话题走向,提出基于数据挖掘技术的网络热点话题演化动态预测算法。首先运用基于块的单遍聚类算法,将网络热点话题划分成不同文本集,根据特征划分到不同块中,进行网络热点话题的数据挖掘,然后计算页面话题热度值,利用热度值描述报道获得的先后顺序,判断能否产生新的网络热点话题,实现网络热点话题预测。经实验验证算法网络热点话题动态预测运行时间少;热点话题预测漏检率低,可精准描述热度值变化趋势。

IMRD架构视角下学术论文创新性评价方法

[目的/意义]引入IMRD架构对论文的关键词进行细分与归类,有利于挖掘各类关键词的潜藏信息,丰富论文创新性评价指标的层次结构和内容,从而提升评价指标的精确性、科学性。[方法/过程]应用文本处理技术和LDA主题模型提取论文的关键词,根据IMRD架构将论文的关键词分为Topic关键词和Method关键词,结合两类关键词的相似度和相似论文数量等因素计算论文相似值,继而根据关键词的类别特征分别构建Topic关键词学科热度值、学术潜力值及Method关键词创新性的数学模型。最后,整合论文创新性的各种影响因素,构建一个多维度、多层次的论文创新性评价指标。[结果/结论]以CNKI数据库中“篇关摘”含有“自然语言处理”的中文期刊论文为实证对象,结果表明本文构建的创新性评价指标能有效区分具有不同创新水平的论文。

基于BBS的热点问题发现

通过提取各种BBS帖子的共有属性来构建指标,计算单个帖子的热度值以及热度指数,以此来挖掘其中的热门话题,为相关分析和预测提供参考。

NUMERICAL SIMULATIONS OF TEMPERATURE FIELD IN DIRECT METAL LASER SINTERING PROCESS

A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.[KH3/4D]

《破冰行动》何以“破冰”

正在爱奇艺热播的电视剧《破冰行动》真实还原了2013年震惊全国的'广东制毒贩毒第一村大案'。以真实大案为蓝本一向是影视剧的题材优势,怎样做出一部高水平的涉案剧,《破冰行动》下了不少硬功夫目前,涉案剧《破冰行动》在爱奇艺平台上的热度值已经超过9000。总制片人戴莹对这个数据做了一番解读:'自爱奇艺前台数据更改为热度值后,热度值突破9000的剧只有《延禧攻略》《都挺好》《破冰行动》。'

一种基于热点的虚拟机存储迁移远程读取方法

对现有基于独立存储的虚拟机动态迁移方法,存在虚拟机迁移时间长、目的端虚拟机远程读取源磁盘文件占用大量网络资源和文件读取响应时间长的问题,本文提出一种基于热点数据的虚拟机存储迁移远程读取方法,在迁移虚拟机存储时优先迁移存储文件中热度值更高的文件部分。该方法首先根据待迁移虚拟机过去时间周期内磁盘文件的访问频率来计算虚拟机磁盘文件热度值,在虚拟机的热迁移过程中采用按文件热度值从高到低的顺序将磁盘文件依次迁移至目的物理机,切换虚拟机服务后在目的端虚拟机访问目的端磁盘文件失败时远程访问源物理主机磁盘文件。实验表明,与现有的基于独立存储的虚拟机的动态迁移方法相比,该方法能够缩短虚拟机磁盘存储的迁移时间,减少虚拟机对源磁盘文件的远程访问次数,从而提高目的端磁盘文件的访问命中率,并缩短磁盘文件读取的平均响应时间,从而提高虚拟机性能。

Numerical simulation of coupled thermo-electrical field for 20 kA new rare earth reduction cell

To solve the problems of high energy consumption,low efficiency and short service life of conventional rare earth reduction cells,a 20 kA new rare earth reduction cell(NRERC)was presented.The effects of the anode-cathode distance(ACD)and electrolyte height(EH)on the thermo-electrical behavior of the NRERC were studied by ANSYS.The results illustrate that the cell voltage drop(CVD)and the temperature will rise with a similar tendency when the ACD increases.Also,the temperature rises gradually with EH,but the CVD decreases.Ultimately,when the ACD is 115 mm and the EH is 380 mm,the CVD is 4.61 V and the temperature is 1109.8℃.Under these conditions,the thermal field distribution is more reasonable and the CVD is lower,which is beneficial to the long service life and low energy consumption of the NRERC.

Frictional heat analysis of mine hoist and numerical simulation on temperature field of gasket

The frictional performance of gaskets is greatly affected by frictional heat in operational mine hoists. Based on frictional mechanism and heat transfer theory, the mathematical model of the temperature field of the PVC gasket in an operational mine hoist was investigated, a numerical simulation using ANSYS is presented and the distribution of the temperature and heat flux were studied under basic assumptions. The results show that the temperature gradually decreases as the radius of the model increases and the isotherms are arcs of concentric semi-circle. The heat flux is of bilateral symmetry in the model and decreases radially. The theoretical values correspond with the measured values for a short time (τ≤ 100 s) when the steel wire rope slides.

Feasibility Research on Application of a High Frequency Induction Heat to Line Heating Technology

The purpose of this paper is to investigate the feasibility of high-frequency induction heat for the line heating process through a series of experimental studies and numerical calculations. The results show that the heating temperature of induction heating meets the demands of steel plate bending, and the deformation of a steel plate heated by induction heating can achieve the same effect as flame heating. Meanwhile, the finite element model of moving induction heating of the plate is developed, and the comparison of the residual strain fields and transverse shrinkage between these two kinds of heating shows that great similarity has been achieved.

Metabolic rate and evaporative water loss in the silky starling （Sturnus sericeus）

To better understand the physiological characteristics of the silky starling（Sturnus sericeus）, its body temperature（Tb）, basal metabolic rate（BMR）, evaporative water loss（EWL） and thermal conductance（C） elicited by different ambient temperatures（Ta）（5-30 ℃） were determined in the present study. Our results showed that they have a high Tb（41.6±0.1 ℃）, a wide thermal neutral zone（TNZ）（20-27.5 ℃） and a relatively low BMR within the TNZ（3.37±0.17 mL O2/g·h）. The EWL was nearly stable below the TNZ（0.91±0.07 mg H2O/g·h） but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O2/g·h·℃. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20℃ and the EWL plays an important role in thermal regulation.

Numerical simulation of temperature distribution and heat transfer during solidification of titanium alloy ingots in vacuum arc remelting process

In order to get a better understanding of the vacuum consumable arc remelting(VAR) processes and thus to optimize them,a 3D finite element model was developed for the temperature fields and heat transfer of titanium alloy ingots during VAR process.The results show that the temperature fields obtained by the simulation are well validated through the experiment results.The temperature distribution is different during the whole VAR process and the steady-state molten pool forms at 329 s for d100 mm × 180 mm ingots.At the initial stage of remelting,the heat dissipation of crucible bottom plays an important role in the whole heat dissipation system.At the middle of remelting,the crucible wall becomes a major heat dissipation way.The effect of cooling velocity on the solidification structure of ingots was investigated based on the temperature fields and the results can well explain the macrostructure of titanium alloy ingots.

Simulation of alumina dissolution and temperature response under different feeding quantities in aluminum reduction cell

In the feeding process of aluminum electrolytic, feeding quantity of alumina affects eventually dissolved quantity at the end of a feeding cycle. Based on the OpenFOAM platform, dissolution model coupled with heat and mass transfer was established. Applying the Rosin-Rammler function, alumina particle size distribution under different feeding quantities was obtained. The temperature response of electrolyte after feeding was included and calculated, and the dissolution processes of alumina with different feeding quantities (0.6, 0.8, 1.0, 1.2, 1.4, 1.6 kg) after feeding were simulated in 300 kA aluminum reduction cell. The results show that with the increase of feeding quantity, accumulated mass fraction of dissolved alumina decreases, and the time required for the rapid dissolution stage extends. When the feeding quantity is 0.6 kg and 1.2 kg, it takes the shortest time for the electrolyte temperature dropping before rebounding back. With the increase of feeding quantity, the dissolution rate in the rapid dissolution stage increases at first and then decreases gradually. The most suitable feeding quantity is 1.2 kg. The fitting equation of alumina dissolution curve under different feeding quantities is obtained, which can be used to evaluate the alumina dissolution and guide the feeding quantity and feeding cycle.

Numerical analysis of heat transfer intensity from twin slot vertical jet impingement on strip surface after hot rolling

The flow field and heat transfer of the strip surface due to the twin slot vertical jet impingement were investigated using the ANSYS FLUENT.The RNG k-ε model was carried out in the turbulent calculation.Systematic parametric research was conducted by varying the jet velocity of nozzle exit(V=5 m/s,7.5 m/s,10 m/s),the temperature of cooling water(T_w=280 K,300 K),the normalized spacing from the nozzle to the strip surface(H=10,15,20,33),and the normalized spacing from the nozzle to nozzle centerline(W=0,15,30).The velocity streamline of the flow domain and the general trend of the distribution of the local Nusselt number on the impingement surface of strip were obtained.The result indicate that,the average Nusselt number increases by about70%(90%) as the jet velocity is increased from 5 m/s to 7.5 m/s(from 7.5 m/s to 10 m/s),and T_w,Hand//have minimal effect on it.While the valley Nusselt number decreases by about 10%-43%with the increase of H and W.The functional relationship between the average Nusselt number and the systematic parameters is derived by the least square regression method.