基于Fitts’law的Twiddler点击绩效模型实验

Fitts＇law是一种被广泛用于点击设备绩效模型评估的重要准则，Twiddle是可穿戴计算机最常用的输入设备。为了对Twiddler的点击绩效进行评估，参考Paul Fitts所采用的反复敲击试验，建立了Twiddler点击绩效测试系统。根据D／W取值的不同，设计了11种测试条件，使得Twiddler点击难度系数ID在1～5的范围内。在大量试验数据的分析基础上，根据不同的Fitts＇law表达式，建立了3种不同的Twiddler点击绩效模型。结合AIC模型判定准则，得到了最优的Twiddler点击绩效模型，模型反映出Twiddler的点击绩效较低，操控比较困难，这些与Twiddler的实际特性相符。在进行可穿戴计算机GUI设计时，应使Twiddler的点击难度系数ID小于4。

基于Fitts定律的指挥信息系统人机交互优化设计

为优化指挥信息系统在交互操作上的流畅性,降低操作时间成本,提升信息化武器的作战效能,文章选取指挥系统中典型场景为研究对象,基于相关领域性特有的强交互性、时效性、严谨性等特征,并结合Fitts定律完成设计策略制定,解决原有指挥系统界面设计中人机交互问题。文章通过分析与实践发现Fitts定理能够在指挥信息系统设计过程中为设计师提供较强的指导性作用,为相关领域设计提供方法论层面指引与参考。

Judicial Facility Upgrade China-assisted state-of-the-art judicial complex construction in Malawi to speed up court processes

A shortage of courtrooms has long been a challenge in Malawi,especially since more judges were hired to help to streamline the country’s judicial process.Yet,while the current judiciary is headquartered in the country’s second-largest city of Blantyre,due to a lack of work space;some sections of the judiciary are located elsewhere,such as the juvenile,commercial and industrial courts.

基于Fitts定律的人体上肢运动功能评定方法

目的 :探讨在临床医学和康复工程等领域中人体运动功能评定的有效方法及原理。方法 :基于Fitts定律 ,参照代表动作执行情况某方面唯一特性的指标———执行度 ,结合速度、能量等其它物理量 ,提出了具有普遍意义的运动功能量化评定方法。选取人体上肢触点运动 ,用Vicon系统对 5名健康男性进行了上肢触点运动实验 ,并通过一组运动功能评定指标 ,对人体上肢触点运动功能进行了量化评定。结果及结论 :人体上肢运动是包含肌肉骨骼和神经系统的高冗余度的系统运动 ,选取基于大系统性能理论的宏观特征作为评定指标对人体上肢运动功能进行量化评定是可行和现实的。鉴于人体结构的复杂性和运动的多样性 ,在对不同动作的评定中 。

Fitts’模型在移动与可穿戴计算交互中的可用性研究

近年来移动计算与可穿戴计算范式已进入高速发展期,此类计算范式通常采用基于手持小屏幕与头戴显示器的受限视场显示技术以及基于多点触摸的指点输入技术。然而此类受限视场显示设备将引起交互过程中的变视场及微目标问题,这些问题可能又将导致人机交互绩效的显著变化,进而影响其交互绩效的传统研究工具——Fitts’模型的可用性。通过人机交互实验,分别针对变视场条件及微目标条件对基于指点交互的人机绩效进行了定量分析,并基于此对Fitts’模型在移动与可穿戴计算中的可用性进行了研究。结果表明传统Fitts’模型不能适用于显示视场小于11.5°或指点目标小于15.7'视弧度的边界条件。最后提出了一个边界条件公式以帮助设计者与用户更好地设计和使用移动与可穿戴计算交互界面及装置。

人机交互领域中Fitts’定律研究

本文综合国内外研究人员利用Fitts’定律进行人机交互界面研究的成果,首先介绍了Fitts’定律是如何提出的;然后,以界面维度为线索,详细介绍了Fitts’定律在人机交互界面研究中的发展与应用;最后,讨论了Fitts’定律在人机交互领域中应用研究的局限性及发展前景。

Fitts’定律实验的设计与实现

首先,介绍了Fitts’定律,然后,设计了验证Fitts’定律的实验,最后,使用Matlab7.0.1对数据进行了统计和分析。实验结果有效地验证了Fitts’定律,并且Fitts’Law(错误率为4%)得到的预测模型精度高于通过"effective width"Fitts’Law得到的预测模型。

基于Fitts定律的虚拟现实小目标选择模型

为了准确地选择虚拟现实人机交互过程中的小目标,避免因手和控制器抖动导致选择精度较低等情况,提出了一种基于Fitts定律的虚拟情境中有效测算小目标交互时间的方法。首先,类比图形用户界面中的移动距离和目标宽度,明确了虚拟情境中Fitts定律的适用性。其次,设计实验并对虚拟情境下的Fitts公式进行回归分析,得到相关系数R^2=0.8963,说明预测时间与真实时间有偏差。接着,利用MATLABcftool拟合工具箱对不同目标尺寸进行回归分析,结合方差分析发现拟合直线的截距与目标尺寸之间显著相关,结合虚拟情境的Fitts公式建立了虚拟现实小目标选择模型。然后,对新模型进行多元回归分析,确定相关系数R^2=0.976 7,说明新模型能够有效预测捕获小目标的时间;分析了运动方向对交互时间的影响,结果表明新模型在不同运动方向下都具有良好的适用性,能够有效指导虚拟情境交互任务中良好目标尺寸的计算。最后,以某VR(virtual reality,虚拟现实)隧道救援体验系统为例进行实验评估。实验结果表明,利用该模型能够在获取虚拟现实小目标时有效减少用户的交互时间,提供更好的用户体验。研究结果能为相关设计开发人员确定虚拟情境下的界面布局提供有效指导,并一定程度上优化用户的交互体验。

从Fitts定律看电子商务网站的可用性设计

以年轻学生作为受试,采用操作测试法和主观评价法,依据Fitts定律考察了可用性设计在网站中的重要性。结果表明,受试者在具有不同可用性设计的网站上进行操作,所花时间、出错次数和偏好上存在巨大差异:在可用性高的网站上进行操作,受试者所花的时间和出错的次数更少,最终也更偏好于这一设计。在此基础上,本文较为深入地分析了其中的原因。

A Note on the Validity of the Shannon Formulation for Fitts’ Index of Difficulty

The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that the Fitts and Welford formulations are valid and that the Shannon formulation is invalid. In this paper, we challenge Hoffmann’s position regarding the Shannon formulation. It is argued that the issue of validity vs. invalidity is ill-conceived, given that Fitts’ law is a “model by analogy” with no basis in human motor control. The relevant questions are of utility: Does a model work? How well? Is it useful? Where alternative formulations exist, they may be critiqued and compared for strengths and weaknesses, but validity is an irrelevant construct. In a reanalysis of data from Fitts’ law experiments, models built using the Shannon formulation are (re)affirmed to be as good as, and generally better than, those built using the Fitts or Welford formulation.

基于多尺度Laws纹理能量和低秩分解的织物疵点检测算法

为提高织物疵点检测算法对简单纹理织物、模式纹理织物及条纹纹理织物检测时的普适性和准确性,提出了一种基于多尺度Laws纹理能量和低秩分解的织物疵点检测算法。首先,对织物图像进行直方图均衡化并将处理后的图像均匀划分为子图像块;其次,对每个子图像块提取28个纹理能量特征(利用7个Laws滤波模板在4个尺度上提取),计算所有子图像块提取到的特征均值并组成特征矩阵;然后,利用特征矩阵构建低秩分解模型,通过方向交替方法(ADM)优化求解,得到低秩部分和稀疏部分;最后,由稀疏部分生成疵点显著图,采用迭代阈值分割法对其进行分割,得到织物疵点检测结果。为验证该算法的有效性,在织物图像数据集选取了包含错纬、断经、跳花、破洞等常见疵点的织物图像,并将实验结果与已有3种算法进行了对比。实验结果表明,该算法在简单纹理织物、模式纹理织物及条纹纹理织物检测上具有更好的普适性和准确性,且检测效率具有一定优势。

基于Fitts定律和模糊融合的远程介入手术系统透明度提升方法研究

心血管介入手术机器人可以避免外科医生遭受X射线辐射,减轻长期穿着防护服造成的疲劳,缓解医疗资源地域不平衡问题。由于存在通讯时延,介入器械的柔性变形和非线性特性使得远程手术系统的透明性难以得到保证。本研究基于Fitts定律和医学经验多元信息进行导管位姿离线模糊融合,实现了柔性导管的位姿预测,通过主手端虚拟现实力触觉渲染得到跟从手端接近一致的力触觉信息,提高了系统的透明性。为了抑制系统的不确定性与非线性,使用自适应滑模控制器提高了系统的鲁棒性。

General laws of funding for scientific citations:how citations change in funded and unfunded research between basic and applied sciences

Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relationship between research funding and citations of papers using 831,337 documents recorded in the Web of Science database.Findings:The original results reveal general characteristics of the diffusion of science in research fields:a)Funded articles receive higher citations compared to unfunded papers in journals;b)Funded articles exhibit a super-linear growth in citations,surpassing the increase seen in unfunded articles.This finding reveals a higher diffusion of scientific knowledge in funded articles.Moreover,c)funded articles in both basic and applied sciences demonstrate a similar expected change in citations,equivalent to about 1.23%,when the number of funded papers increases by 1%in journals.This result suggests,for the first time,that funding effect of scientific research is an invariant driver,irrespective of the nature of the basic or applied sciences.Originality/value:This evidence suggests empirical laws of funding for scientific citations that explain the importance of robust funding mechanisms for achieving impactful research outcomes in science and society.These findings here also highlight that funding for scientific research is a critical driving force in supporting citations and the dissemination of scientific knowledge in recorded documents in both basic and applied sciences.Practical implications:This comprehensive result provides a holistic view of the relationship between funding and citation performance in science to guide policymakers and R&D managers with science policies by directing funding to research in promoting the scientific development and higher diffusion of results for the progress of human society.

Weber Law Based Approach for Multi-Class Image Forgery Detection

Today’s forensic science introduces a new research area for digital image analysis formultimedia security.So,Image authentication issues have been raised due to the wide use of image manipulation software to obtain an illegitimate benefit or createmisleading publicity by using tempered images.Exiting forgery detectionmethods can classify only one of the most widely used Copy-Move and splicing forgeries.However,an image can contain one or more types of forgeries.This study has proposed a hybridmethod for classifying Copy-Move and splicing images using texture information of images in the spatial domain.Firstly,images are divided into equal blocks to get scale-invariant features.Weber law has been used for getting texture features,and finally,XGBOOST is used to classify both Copy-Move and splicing forgery.The proposed method classified three types of forgeries,i.e.,splicing,Copy-Move,and healthy.Benchmarked(CASIA 2.0,MICCF200)and RCMFD datasets are used for training and testing.On average,the proposed method achieved 97.3% accuracy on benchmarked datasets and 98.3% on RCMFD datasets by applying 10-fold cross-validation,which is far better than existing methods.

Scaling Laws Behind Penetrative Turbulence:History and Perspectives

An unstably stratified flow entering into a stably stratified flow is referred to as penetrative convection,which is crucial to many physical processes and has been thought of as a key factor for extreme weather conditions.Past theoretical,numerical,and experimental studies on penetrative convection are reviewed,along with field studies providing insights into turbulence modeling.The physical factors that initiate penetrative convection,including internal heat sources,nonlinear constitutive relationships,centrifugal forces and other complicated factors are summarized.Cutting-edge methods for understanding transport mechanisms and statistical properties of penetrative turbulence are also documented,e.g.,the variational approach and quasilinear approach,which derive scaling laws embedded in penetrative turbulence.Exploring these scaling laws in penetrative convection can improve our understanding of large-scale geophysical and astrophysical motions.To better the model of penetrative turbulence towards a practical situation,new directions,e.g.,penetrative convection in spheres,and radiation-forced convection,are proposed.

Closed-form guidance law for velocity maximization with impact angle constraint

Final velocity and impact angle are critical to missile guidance.Computationally efficient guidance law with compre-hensive consideration of the two performance merits is challeng-ing yet remains less addressed.Therefore,this paper seeks to solve a type of optimal control problem that maximizes final velocity subject to equality point constraint of impact angle con-straint.It is proved that the crude problem of maximizing final velocity is equivalent to minimizing a quadratic-form cost of cur-vature.The closed-form guidance law is henceforth derived using optimal control theory.The derived analytical guidance law coincides with the widely-used optimal guidance law with impact angle constraint(OGL-IAC)with a set of navigation parameters of two and six.On this basis,the optimal emission angle is determined to further increase the final velocity.The derived optimal value depends solely on the initial line-of-sight angle and impact angle constraint,and thus practical for real-world appli-cations.The proposed guidance law is validated by numerical simulation.The results show that the OGL-IAC is superior to the benchmark guidance laws both in terms of final velocity and missing distance.

Nonuniform Dependence on the Initial Data for Solutions of Conservation Laws

In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results apply to all nonlinear scalar conservation laws and to nonlinear hyperbolic systems of two equations.

Triple reverse order law for the Drazin inverse

In this paper,we investigate the reverse order law for Drazin inverse of three bound-ed linear operators under some commutation relations.Moreover,the Drazin invertibility of sum is also obtained for two bounded linear operators and its expression is presented.

Literature overview of basic characteristics and flotation laws of flocs

Flocculation flotation is the most efficient method for recovering fine-grained minerals,and its essence lies in flotation and recovery of flocs.Fundamental physical characteristics of flocs are mainly determined by their apparent particle size and structure(density and morphology).Substantial researches have been conducted regarding the effect of floc characteristics on particle settling and water treatment.However,the influence of floc characteristics on flotation has not been widely studied.Based on the floc formation and flocculation flotation,this study reviews the fundamental physical characteristics of flocs from the perspectives of floc particle size and structure,summarizing the interaction between floc particle size and structure.Moreover,it thoroughly discusses the effect of floc particle size and structure on floc floatability,further revealing the influence of floc characteristics on bubble collision and adhesion and elucidating the mechanisms of interaction between flocs and bubbles.Thus,it is observed that floc particle size is not the only factor influencing flocculation flotation.Within the appropriate apparent particle size range,flocs with a compact structure exhibit higher efficiency in bubble collision and adhesion during flotation,thereby resulting in enhanced flotation performance.This study aims to provide a reference for flocculation flotation,targeting the development of more efficient and refined flocculation flotation processes in the future.

Dimension by Dimension Finite Volume HWENO Method for Hyperbolic Conservation Laws

In this paper,we propose a finite volume Hermite weighted essentially non-oscillatory(HWENO)method based on the dimension by dimension framework to solve hyperbolic conservation laws.It can maintain the high accuracy in the smooth region and obtain the high resolution solution when the discontinuity appears,and it is compact which will be good for giving the numerical boundary conditions.Furthermore,it avoids complicated least square procedure when we implement the genuine two dimensional(2D)finite volume HWENO reconstruction,and it can be regarded as a generalization of the one dimensional(1D)HWENO method.Extensive numerical tests are performed to verify the high resolution and high accuracy of the scheme.