Standardisation of digital human models

Digital human models (DHM) have evolved as useful tools for ergonomic workplace design and product development, and found in various industries and education. DHM systems which dominate the market were developed for specific purposes and differ significantly, which is not only reflected in non-compatible results of DHM simulations, but also provoking misunderstanding of how DHM simulations relate to real world problems. While DHM developers are restricted by uncertainty about the user need and lack of model data related standards, users are confined to one specific product and cannot exchange results, or upgrade to another DHM system, as their previous results would be rendered worthless. Furthermore, origin and validity of anthropometric and biomechanical data is not transparent to the user. The lack of standardisation in DHM systems has become a major roadblock in further system development, affecting all stakeholders in the DHM industry. Evidently, a framework for standardising digital human models is necessary to overcome current obstructions. Practitioner Summary: This short communication addresses a standardisation issue for digital human models, which has been addressed at the International Ergonomics Association Technical Committee for Human Simulation and Virtual Environments. It is the outcome of a workshop at the DHM 2011 symposium in Lyon, which concluded steps towards DHM standardisation that need to be taken.     

Spatial frequencies in aesthetic website evaluations--explaining how ultra-rapid evaluations are formed

This study investigates how aesthetic website evaluations, especially those formed after very brief presentations, depend on visual information that is encoded in low- or high-spatial frequencies. A total of 92 participants took part in the experiment. The study used a 3 × 3 mixed design in which presentation time (50, 500 and 10000 ms) and spatial filtering (low-pass filtered, high-pass filtered and unfiltered stimuli) were manipulated. First, we replicate prior results from online studies of high- and low-spatial frequencies. Second, we confirm a prediction from neurocognitive models that only low-spatial frequencies are relevant to aesthetic judgements in ultra-rapid presentation modes. Third, we demonstrate that stimulus repetitions lead to an overestimation of the importance of ultra-rapid stimulus presentations. Taken together, our results highlight the utility of neurocognitive models of visual processing to explain the rapid aesthetic evaluation of websites. PRACTITIONER SUMMARY: Using neurocognitive models we present an approach to explain how aesthetic impressions are formed. We show that ultra-rapid judgements are connected with low- but not with high-spatial frequencies, which are neurologically processed in different visual pathways. Furthermore we identify possible methodological problems in previous studies of ultra-rapid website perception.     

Inhibition effect of a synthesized N, N＇-bis（2-hydroxybenzaldehyde）- 1, 3-propandiimine on corrosion of mild steel in HC1

The corrosion inhibition of mild steel in 1 mol/L HCl by N, N′-bis (2-hydroxybenzaldehyde)-1, 3-propandiimine (2-HBP) has been investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and chronoamperometry measurements. The experimental results suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. Polarization curves reveal that this organic compound is a mixed type inhibitor. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25℃ to 65℃. The experimentally obtained adsorption isotherms follow the Langmuir equation. Activation and thermodynamic adsorption parameters such as E a , ΔH, ΔS, K ads and ΔG ads were calculated by the corrosion currents at different temperatures and using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of 2-HBP was examined by atomic force microscope (AFM) images.     

混凝土搅拌车副车架有限元分析及优化设计

利用ANSYS软件对某型号混凝土搅拌车副车架的静动态特性进行仿真分析,通过CATIA软件建立副车架三维实体模型,并导入ANSYS有限元分析软件进行静力学分析,得到副车架最大应力分布及变形情况后进行拓扑结构优化设计,提出副车架新结构并进行模态分析验证其动态性能,为该型号混凝土搅拌车副车架结构设计提供了一定的指导.     

直线输电塔横梁变化抗震性能反应分析

输电塔结构性能比较高效,适用性很强,广泛地应用到电力工程中。采用SAP2000对横梁数量不同的三种输电塔结构在地震作用下进行动力时程分析,比较几种输电塔结构的抗震动力响应。计算结果表明,随着横梁数量变多,输电塔的整体刚度就变大,模态分析中的周期减小,同时结构的顶点位移和加速度也减小了,可是,结构的钢材料杆件的轴力和固定支座的反力却增大了,因此在地震中,横梁数量越多,结构抗震性能不一定越好。要合理布置横梁数量,优化结构抗震性能。     

故障齿轮啮合刚度综合计算方法

为了有效、准确地计算含故障齿轮的时变啮合刚度,提出了一种基于传统能量法的改进方法,结合改进能量法和有限元法的各自优点,即应用改进能量法快速计算故障齿轮无故障轮齿的啮合刚度,利用有限元法精确地计算故障轮齿有故障部位的啮合刚度.仿真示例结果表明:与能量法和有限元法相比,该方法能快速、准确地仿真故障齿轮的时变啮合刚度并且适用于齿轮系统振动响应的计算.     

具有落角约束的弹道导弹再入末制导律设计

针对弹道导弹再入段带有终端落角约束的末制导问题,本文基于最新发展起来的模型预测静态规划技术,设计一种既可以精确地打击地面目标、又可以满足终端碰撞角要求的非线性次优制导律．本文针对弹道导弹打击地面静止目标和机动目标等飞行场景进行了数值仿真,仿真结果表明:采用该制导律可以使在整个再入飞行场景中控制能量较小．与其他具有落角约束的制导律相比,该制导律并没有对非线性运动模型采用线性化的假设,且其计算复杂性明显低于基于最优控制的终端角约束制导律．     

基于FAHP的服装产业集群品牌绩效评价体系研究

从产业集群升级到产业集群品牌是提升我国服装产业集群能级的重要途径,服装产业集群品牌的绩效评价是有针对性的识别和解决其构建和维护过程中存在问题的关键．通过总结前人相关理论,在系统分析区域（集群）品牌成长机制和影响因素理论的基础上,结合服装行业的特点构建出服装产业集群品牌绩效的评价指标体系,并采用FAHP（FuzzyAnalyticHierarchyProcess,即模糊层次分析法）法确定各指标的权重系数．可以看出,产业集群状况及其下辖的信息获取对于服装集群品牌绩效的影响最为重要,其次为企业品牌集聚,影响力最为薄弱的外部环境因素．构建服装产业集群品牌绩效评价体系对于企业和政府采取有效的战略决策提供参考依据．     

滚针轴承冲压件的毛坯拉深计算系统开发

基于SolidWorks构建冲压件三维模型,以Access 2007作为后台数据库,利用VB作为开发语言,设计开发出能自动计算冲压件毛坯尺寸及其拉深次数的软件系统。实践证明,其功能可靠准确,计算出的毛坯尺寸与企业实际生产中所用的毛坯尺寸基本一致,有效提高了材料的利用率和工作效率。