数据挖掘取样方法研究

取样方法这种有效的近似技术在现在的数据挖掘研究中能够最大限度的减小数据集的处理规模,将大规模数据集及数据流数据上以数据挖掘算法进行处理。取样法具有通用有效的特点。本文化通过对数据挖掘领域的取样方法分类以及影响取样方法选择的因素等问题进行分析研究,着重探讨了数据挖掘领域的代表性取样方选用以及应用发展。     

数据挖掘在对教师档案和教学质量评分关联分析的应用

本文以当前的高职教育教学为平台,利用数据挖掘技术对教师学历结构、年龄结构、教师能力结构、＂双师型＂比例、专/兼职结构等因素对教师教学质量水平的影响进行了关联分析研究,对评价信息进行分析、统计并做出结论。通过对学生评教数据和教师的档案数据进行数据挖掘,利用关联规则挖掘算法挖掘影响教学质量的关键因素,并对挖掘结果进行了分析...     

数据挖掘技术在企业培训质量评估中的应用

通过对数据挖掘决策树算法的研究,应用Microsoft SQLServer2000 Analysis Services完成培训质量评估数据的分析,发现了影响培训质量的关键因素,为培训策划及实施管理提供了依据,有利于提高培训质量。     

模糊控制在暖体假人温控系统中的应用

本文介绍了服装保暖量测量手段－暖体假人系统的构成及基本原理，对其控制算法进行比较深入细致的探索，针对系统特点引入Ｆｕｚｚ－ＰＩ控制算法，使系统取得良好的特性。     

过程数据挖掘及进展

工业过程已是一个海量的数据源,需要从中提取知识以支持过程优化.分析了工业过程数据的特点,将数据挖掘了思想引入生产过程优化中,提出了工业过程数据挖掘了概念,即是一个依赖精确的数学模型,而自动或半自动地从工业过程数据中撮有用的知识,以支持过程变量预报、过程优化及过程故障诊断的特殊数据处理过程.总结了过程数据挖掘在过程变量预报、过程监视与优化及过程故障诊断中的研究进展,得出过程数据挖掘应在算法的设计、商业软件的开发及过程数据仓库与过程数据挖掘的集成三方面开展创新工作的结论.     

过程数据挖掘及进展

工业过程已是一个海量的数据源,需要从中提取知识以支持过程优化。分析了工业过程数据的特点,将数据挖掘的思想引入生产过程优化中,提出了工业过程数据挖掘的概念,即是一个不依赖精确的数学模型,而自动或半自动地从工业过程数据中提取有用的知识,以支持过程变量预报、过程优化及过程故障诊断的特殊数据处理过程。总结了过程数据挖掘在过程变量预报、过程监视与优化及过程故障诊断中的研究进展,得出过程数据挖掘应在算法的设计、商业软件的开发及过程数据仓库与过程数据挖掘的集成三方面开展创新工作的结论。     

基于动态代价敏感的数据挖掘算法探讨

信息时代的到来,数据作为信息的载体其重要性也愈加突出,随着人们对不确定数据研究的深入,代价敏感数据挖掘技术被应用于不确定数据挖掘中。本文介绍了不确定数据,分析了现有不确定数据挖掘方法,在介绍代价敏感学习的基础上,介绍了一种针对不确定数据的代价敏感决策树算法,并通过实验验证了这一算法的合理可行。     

卫星导航系统安全防护研究

卫星导航系统安全防护对导航以及武器装备具有极其重要的意义。首先介绍了卫星导航系统安全防护的定义、描述和研究内容;然后根据系统工程思想,给出了研究卫星导航系统安全防护问题的一般思路;接着给出了一个综合考虑干扰策略、攻击水平、防护水平、作战场景等安全防护因素的数学模型;最后通过算例分析了接收机的安全防护。实验结论显示,相对于敌方攻击水平的防护水平是影响我方作战效用的关键因素,不同作战任务场景对安全防护的要求是不同的,攻击策略对作战效能的影响取决于相应防护水平的强弱。     

高维数据挖掘中基于中位数回归的特征提取新方法

为降低噪声对数据特征提取(变量选择)效果的不利影响,基于中位数回归分析方法,利用变量选择降维技术(正则化估计),提出了一种稳健、有效的特征提取(变量选择)新方法,并具体给出了估计算法,该算法具有快速计算的特点.实验结果表明,新方法能够有效地对高维数据集进行估计和变量选择,且具有较高的准确性,即使数据中的信噪比很低时,该方法仍具有较好的效果.因此,该方法为高维数据挖掘特征提取提供了稳健且有效的方法.     

基于神经网络的丙酮产品质量分类挖掘

针对丙酮精制过程的特点，提出一种基于神经网络的丙酮产品质最分类挖掘方法。首先，讨论了数据挖掘中自变量筛选的方法，包括相关性分析、Fisher指数分析、主成分回归分析以及偏最小二乘回归分析等，综合各种疗法分析的结果，对丙酮精制过程中众多的工艺影响因素进行了重要性排序并据此筛选出重要的自变量；以选入的变量作为输入变量，构造基于神经网络的产品质量分类器。实验结果表明，训练后的神经网络分类器在丙酮产品质量分类挖掘中取得了良好的效果。     

Global and local heat transfer analysis for bicycle helmets using thermal head manikins

Predicting thermal comfort of protective headgear is of particular interest since the head is one of the most heat-sensitive body parts. Thermal head manikins enable systematic investigation of heat transfer properties of headgear. Such investigation provides valuable inputs for the development of new helmet concepts to improve thermal comfort.This study presents a nine-zone thermal head manikin (9zM) to evaluate local heat transfer effects of headgear. Performance of the new manikin and local data were assessed by comparing with data from a two-zone thermal head manikin (2zM) published previously. Variation for heat flux data was found to be lower for 9zM than for 2zM in tests including convective and radiative heat transfer. The calculation of radiant heat gain revealed similar variation at cranial section for both manikins but it increased at facial section for 9zM. Classification of helmets based on heat transfer data differed for head manikins likely due to slight differences in head geometries. Moreover, local heat transfer data obtained from the 9zM allowed a more detailed investigation of headgear properties. This knowledge contributes to a better understanding of the thermal interaction of head and headgear and, therefore, to a more justified development of optimised headgear designs.     

3D quantification of microclimate volume in layered clothing for the prediction of clothing insulation

Garment fit and resultant air volume is a crucial factor in thermal insulation, and yet, it has been difficult to quantify the air volume of clothing microclimate and relate it to the thermal insulation value just using the information on the size of clothing pattern without actual 3D volume measurement in wear condition. As earlier methods for the computation of air volume in clothing microclimate, vacuum over suit and circumference model have been used. However, these methods have inevitable disadvantages in terms of cost or accuracy due to the limitations of measurement equipment. In this paper, the phase-shifting moiré topography was introduced as one of the 3D scanning tools to measure the air volume of clothing microclimate quantitatively. The purpose of this research is to adopt a non-contact image scanning technology, phase-shifting moiré topography, to ascertain relationship between air volume and insulation value of layered clothing systems in wear situations where the 2D fabric creates new conditions in 3D spaces. The insulation of vests over shirts as a layered clothing system was measured with a thermal manikin in the environmental condition of 20 degrees C, 65% RH and air velocity of 0.79 m/s. As the pattern size increased, the insulation of the clothing system was increased. But beyond a certain limit, the insulation started to decrease due to convection and ventilation, which is more apparent when only the vest was worn over the torso of manikin. The relationship between clothing air volume and insulation was difficult to predict with a single vest due to the extreme openings which induced active ventilation. But when the vest was worn over the shirt, the effects of thickness of the fabrics on insulation were less pronounced compared with that of air volume. In conclusion, phase-shifting moiré topography was one of the efficient and accurate ways of quantifying air volume and its distribution across the clothing microclimate. It is also noted that air volume becomes more crucial factor in predicting thermal insulation when clothing is layered.     

A novel approach for fit analysis of thermal protective clothing using three-dimensional body scanning

The garment fit played an important role in protective performance, comfort and mobility. The purpose of this study is to quantify the air gap to quantitatively characterize a three-dimensional (3-D) garment fit using a 3-D body scanning technique. A method for processing of scanned data was developed to investigate the air gap size and distribution between the clothing and human body. The mesh model formed from nude and clothed body was aligned, superimposed and sectioned using Rapidform software. The air gap size and distribution over the body surface were analyzed. The total air volume was also calculated. The effects of fabric properties and garment size on air gap distribution were explored. The results indicated that average air gap of the fit clothing was around 25–30 mm and the overall air gap distribution was similar. The air gap was unevenly distributed over the body and it was strongly associated with the body parts, fabric properties and garment size. The research will help understand the overall clothing fit and its association with protection, thermal and movement comfort, and provide guidelines for clothing engineers to improve thermal performance and reduce physiological burden.     

The effect of added fullness and ventilation holes in T-shirt design on thermal comfort

This paper reports on an experimental investigation on the effect of added fullness and ventilation holes in T-shirt design on clothing comfort measured in terms of thermal insulation and moisture vapour resistance. Four T-shirts in four different sizes (S, M, L, XL) were cut under the traditional sizing method while another (F-1) was cut with specially added fullness to create a 'flared' drape. A thermal manikin 'Walter' was used to measure the thermal insulation and moisture vapour resistance of the T-shirts in a chamber with controlled temperature, relative humidity and air velocity. The tests included four conditions: manikin standing still in the no-wind and windy conditions and walking in the no-wind and windy condition. It was found that adding fullness in the T-shirt design (F-1) to create the 'flared' drape can significantly reduce the T-shirt's thermal insulation and moisture vapour resistance under walking or windy conditions. Heat and moisture transmission through the T-shirt can be further enhanced by creating small apertures on the front and back of the T-shirt with specially added fullness. STATEMENT OF RELEVANCE: The thermal comfort of the human body is one of the key issues in the study of ergonomics. When doing exercise, a human body will generate heat, which will eventually result in sweating. If heat and moisture are not released effectively from the body, heat stress may occur and the person's performance will be negatively affected. Therefore, contemporary athletic T-shirts are designed to improve the heat and moisture transfer from the wearer. Through special cutting, such athletic T-shirts can be designed to improve the ventilation of the wearer.     

基于自适应神经模糊控制的暖体假人温控系统

针对用传统PID方法设计的暖体假人温控制系统存在参数难以整定、调整，试验效率较低的情况，将自适应模糊控制技术与神经网络技术相结合，提出了一种自适应神经模糊控制器的实现方法，并结合一种改进的快速BP算法来训练网络，设计了暖体假人温控制系统，实验结果表明该系统有效地缩短了服装热学性能的试验时间，提高了实验精度和实验效率。     

Effect of posture positions on the evaporative resistance and thermal insulation of clothing

Evaporative resistance and thermal insulation of clothing are important parameters in the design and engineering of thermal environments and functional clothing. Past work on the measurement of evaporative resistance of clothing was, however, limited to the standing posture with or without body motion. Information on the evaporative resistance of clothing when the wearer is in a sedentary or supine posture and how it is related to that when the wearer is in a standing posture is lacking. This paper presents original data on the effect of postures on the evaporative resistance of clothing, thermal insulation and permeability index, based on the measurements under three postures, viz. standing, sedentary and supine, using the sweating fabric manikin-Walter. Regression models are also established to relate the evaporative resistance and thermal insulation of clothing under sedentary and supine postures to those under the standing posture. The study further shows that the apparent evaporated resistances of standing and sedentary postures measured in the non-isothermal condition are much lower than those in the isothermal condition. The apparent evaporative resistances measured using the mass loss method are generally lower than those measured using the heat loss method due to moisture absorption or condensation within clothing. STATEMENT OF RELEVANCE: The thermal insulation and evaporative resistance values of clothing ensembles under different postures are essential data for the ergonomics design of thermal environments (e.g. indoors or a vehicle's interior environment) and functional clothing. They are also necessary for the prediction of thermal comfort or duration of exposure in different environmental conditions.     

The effect of unevenly distributed thermal stimuli on the sensation of warmth and coolness

Combinations of clothing provide different degrees of thermal insulation for various parts of the body. The effect of this uneven thermal insulation on general comfort is examined by using experimental clothing which could provide varying degrees of thermal resistance. The relationship between skin temperature and sensation was found to be approximately linear when the exposed areas were not large, and that clothing of the same thermal resistance can yield different sensations depending on the parts of the body involved.     

秦岭特长公路隧道火灾数值仿真研究

该文通过计算机建立了实验中所用的秦岭特长公路隧道的数值模型，并采用与实验中相同的火灾规模和边界条件对不同风速下隧道拱顶纵向温度分布进行了数值仿真研究。将仿真的结果和实验数据进行了比较，实现了对这个数值模型的有效性的验证。然后，采用这个数值模型对秦岭特长公路隧道发生火灾时的热环境进行了数值仿真研究，获得了从实验中很难得到的数据并在此基础是对隧道的性能化防火设计、消防安全措施、特别是对人员的在火灾时的安全逃生作了可靠的分析和预测。     

Cooling vests with phase change material packs: the effects of temperature gradient,mass and covering area

Phase change material (PCM) absorbs or releases latent heat when it changes phases, making thermal-regulated clothing possible. The objective of this study was to quantify the relationships between PCM cooling rate and temperature gradient, mass and covering area on a thermal manikin in a climatic chamber. Three melting temperatures (24, 28, 32°C) of the PCMs, different mass, covering areas and two manikin temperatures (34 and 38°C) were used. The results showed that the cooling rate of the PCM vests tested is positively correlated with the temperature gradient between the thermal manikin and the melting temperature of the PCMs. The required temperature gradient is suggested to be greater than 6°C when PCM vests are used in hot climates. With the same temperature gradient, the cooling rate is mainly determined by the covering area. The duration of the cooling effect is dependent on PCM mass and the latent heat.

Statement of Relevance: The study of factors affecting the cooling rate of personal cooling equipment incorporated with PCM helps to understand cooling mechanisms. The results suggest climatic conditions, the required temperature gradient, PCM mass and covering area should be taken into account when choosing personal PCM cooling equipment.