Computer experience, learning style, and hypermedia navigation

This study focused on the extent to which prior computer-related experiences predicted linear and nonlinear navigation when using a hypermedia learning environment. Those with more years’ experience at working with computers and those with more authoring experience took more linear steps, whereas those with more data base experience and those with more hypermedia experience took fewer linear steps. Those with more years experience at working with computers, those with more programming experience, and those with more authoring experience had a lower percentage of nonlinear steps than those with more experience in those three areas. Those with more word-processing experience, more spreadsheet experience, and more hypermedia experience had a higher percentage of nonlinear steps than those with less experience in those three areas. Also, those with more hypermedia experience took less time than those with less hypermedia experience. A major implication of the study is that we can predict the extent to which a hypermedia user may engage in a hypermedia environment in a nonlinear way by knowing his or her experience in a variety of computer-related uses.     

Control 5.0: From Newton to Merton in Popper's Cyber-Social-Physical Spaces

The future of control in cyberspace of parallel worlds is discussed. It argues for the coming age of Control 5.0, the control technology for the new IT capable of dealing with artificial worlds with VR, AR, AI and robotics. The discipline of automation needs a new interpretation of its core knowledge and skill set of modeling, analysis, and control for cyber-socialphysical systems, and a paradigm shift from Newtonian Systems with Newton's Laws or Big Laws with Small Data to Mertonian Systems with Merton's Laws or Small Laws with Big Data.      

The impact of communication technologies on life and relationship satisfaction

Previous studies have shown a relationship between the use of communications technology and well-being, particularly mediated through its effect on personal relationships. However, there is some debate over whether this effect is positive or negative. The present study explored this issue further, examining whether the effect varies depending on the type of communications technology, and the nature of the personal relationship. An online survey was conducted with 3421 participants in three countries (Australia, UK and US). It examined the use of ten communication methods, overall satisfaction with life and satisfaction with four different kinds of relationships (close and extended family, and close and distant friends).Results indicate that richer communication methods, which include non-verbal cues, were positively associated with both overall satisfaction with life and satisfaction with relationships. These methods included face-to-face communication, and phone and video calls. Conversely, more restricted methods, such as text messaging and instant messaging, were negatively associated with both variables. Social networking was negatively associated with overall satisfaction, but not with satisfaction with relationships. The strength of the association between a communications method and satisfaction with a relationship varied depending on the type of relationship, but whether it was positive or negative did not change.     

Integrated text entry from power wheelchairs

Power wheelchair joysticks have be used to control a mouse cursor on desktop computers, but they offer no integrated text entry solution, confining users to point-and-click or point-and-dwell with on-screen keyboards. On-screen keyboards reduce useful screen real-estate, exacerbating the need for frequent window management, and impose a secondary focus of attention. By contrast, we present two integrated gestural text entry methods designed for use from power wheelchairs: one for use with joysticks and the other for use with touchpads. Both techniques are adaptations of EdgeWrite, originally a stylus-based unistroke method designed for people with tremor. In a preliminary text entry study of 7 power wheelchair users, we found that EdgeWrite with a touchpad was faster than the on-screen keyboard WiViK with a joystick, and EdgeWrite with a joystick was only slightly slower. These results warranted a multi-session comparison of text entry with EdgeWrite and WiViK using joysticks and touchpads, in which we found touchpads faster than joysticks, and EdgeWrite faster than WiViK with both devices after initial learning periods.     

Multibody systems with 3D revolute joints with clearances: an industrial case study with an experimental validation

This article is devoted to the analysis of the influence of the joint clearances in a mechanism of a circuit breaker, which is a 42 degree-of-freedom mechanism made of seven links, seven revolute joints, and four unilateral contacts with friction. Spatial (3D) revolute joints are modeled with both radial and axial clearances taking into account contact with flanges. Unilateral contact, Coulomb’s friction and Newton impact laws are modeled within the framework of nonsmooth mechanics without resorting to some regularizations or compliance/damping at contact. The nonsmooth contact dynamics method based on an event-capturing time-stepping scheme with a second order cone complementarity solver is used to perform the numerical integration. Furthermore, the stabilization of the constraints at the position level is made thanks to the stabilized combined projected Moreau–Jean scheme. The nonsmooth modeling approach together with an event–capturing time-stepping scheme allows us to simulate, in an efficient and robust way, the contact and impacts phenomena that occur in joints with clearances. In particular, comparing with the event-detecting time-stepping schemes, the event-capturing scheme enables us to perform the time-integration with a large number of events (impacts, sliding/sticking transitions, changes in the direction of sliding) and possibly with finite-time accumulations with a reasonable time-step length. Comparing with compliant contact models, we avoid stiff problems related with high stiffnesses at contact which generate some issues in contact stabilization and spurious oscillations during persistent contact periods. In the studied mechanisms of the circuit breakers, the numerical method deals with more than 70 contact points without any problems. Furthermore, the number of contact parameters is small—one coefficient of restitution and one coefficient of friction. Though they are sometimes difficult to measure accurately, the sensitivity of the simulation result with respect to contact parameters is low in the mechanism of the circuit breaker. It is demonstrated that this method, thanks to its robustness and efficiency, allows us to perform a sensitivity analysis using a Monte Carlo method. The numerical results are also validated by careful comparisons with experimental data, showing a very good correlation.     

Probabilistic characteristics of paramacrosystems

Consideration is given to macrosystems called paramacrosystems with different elements, with stochastic behavior, and states of finite capacity. Thus is fulfilled the interval between two classical capacity characteristics of states: Fermi, with one element, and Einstein, with unlimited number of elements in each state. Using the apparatus of generating functions, we obtained expressions for probabilistic characteristics (functions of probability distribution and “physical” entropies) for four classes of paramacrosystems with corresponding combinations of distinguishable and indistinguishable elements and states with finite capacities.     

Worm wheel mechanism with passive rollers

In this study, we developed new worm wheel mechanisms with passive rollers as their teeth and confirmed useful functions of these worm wheels with passive rollers to transmit power from worm gears with higher energy efficiency than ordinary worm wheels. By using passive rollers as their teeth, the developed worm wheels could realize high-power transmission efficiency with rolling frictional resistance instead of sliding frictional resistance. A worm wheel with conical passive rollers and one with disk-shaped passive rollers was fabricated as prototypes and examined in experiments. Smooth back-drivability of the worm wheels with passive rollers, which is difficult to realize with conventional worm wheels, was also demonstrated in the experiments. These serial experiments revealed that the developed worm wheel mechanism with passive rollers can replace conventional worm wheels with the same number of teeth and module in ordinary power transmission mechanisms with worm gearing and realize higher energy efficiency and smooth back-drivability. These features can be very useful to realize safe and soft actuators for automation systems in a human environment.     

Effects of child restraint system features on installation errors

This study examined how child restraint system (CRS) features contribute to CRS installation errors. Sixteen convertible CRS, selected to include a wide range of features, were used in volunteer testing with 32 subjects. Subjects were recruited based on their education level (high or low) and experience with installing CRS (none or experienced). Each subject was asked to perform four child restraint installations in the right-rear passenger seat of a 2006 Pontiac G6 sedan using a crash dummy as a child surrogate. Each subject installed two CRS forward-facing (FF), one with LATCH and one with the vehicle seatbelt, and two CRS rear-facing (RF), one with LATCH and one with the seatbelt. After each installation, the experimenter evaluated 42 factors for each installation, such as choice of belt routing path, tightness of installation, and harness snugness.Analyses used linear mixed models to identify CRS installation outcomes associated with CRS features. LATCH connector type, LATCH strap adjustor type, and the presence of belt lockoffs were associated with the tightness of the CRS installation. The type of harness shoulder height adjuster was associated with the rate of achieving a snug harness. Correct tether use was associated with the tether storage method. In general, subject assessments of the ease-of-use of CRS features were not highly correlated with the quality of their installation, suggesting a need for feedback with incorrect installations.The data from this study provide quantitative assessments of some CRS features that were associated with reductions in CRS installation errors. These results provide child restraint designers with design guidelines for developing easier-to-use products. Research on providing effective feedback during the child restraint installation process is recommended.     

面向计算机的产品创新设计新模型与新原理(II)

该文基于物元动态系统理论提出了产品虚实模型、产品潜显模型、产品正负模型等产品创新设计模型,分析了产品的同素多构性、一关系多实体性、同构多素性、虚实统一性、一显多潜性、一正多负性等性质。给出在一定的条件下,异构同功,异素同功、同潜产品同功,以及同正产品可互相转化产品、同负产品可互相转化的产品创新设计新原理。新模型和新原理有利于开发计算机辅助产品创新设计系统CAPCDS。     

DOGeye: Controlling your home with eye interaction

Nowadays home automation, with its increased availability, reliability and with its ever reducing costs is gaining momentum and is starting to become a viable solution for enabling people with disabilities to autonomously interact with their homes and to better communicate with other people. However, especially for people with severe mobility impairments, there is still a lack of tools and interfaces for effective control and interaction with home automation systems, and general-purpose solutions are seldom applicable due to the complexity, asynchronicity, time dependent behavior, and safety concerns typical of the home environment. This paper focuses on user-environment interfaces based on the eye tracking technology, which often is the only viable interaction modality for users as such. We propose an eye-based interface tackling the specific requirements of smart environments, already outlined in a public Recommendation issued by the COGAIN European Network of Excellence. The proposed interface has been implemented as a software prototype based on the ETU universal driver, thus being potentially able to run on a variety of eye trackers, and it is compatible with a wide set of smart home technologies, handled by the Domotic OSGi Gateway. A first interface evaluation, with user testing sessions, has been carried and results show that the interface is quite effective and usable without discomfort by people with almost regular eye movement control.     

An interactive tool to promote musical creativity in people with dementia

Dementia is a growing problem that affects the lives of those diagnosed and caregivers, with symptoms having an effect on memory, communication, the ability to learn new skills and problems with behaviour, such as aggression, agitation and depression. Participation in activities can improve quality of life for people with dementia, reducing behavioural problems and aiding relaxation. Research has established that people with dementia can be both artistically and musically creative, and have an appreciation of music even in the latter stages of the disease. The symptoms of the disease, however, mean that supporting music making activities with this group of people is challenging. This paper describes a prototype system designed to enable people with dementia to create music, using a touch screen interface to control a system which utilises chords to create pleasant-sounding music regardless of any prior musical knowledge. Results of usability studies suggest the system is easy to use, and that pleasant-sounding music can be created with it. Participants, including people with dementia, appeared actively engaged during use of the system, many reporting they enjoyed the experience. Future testing will establish the degree to which people with dementia could be musically creative using such a system.     

制砚艺术规律探讨

砚,俗称砚台。融合了书法、绘画和雕刻艺术的精华,是实用品和艺术品的结晶,是我国传统文化的产物。随着社会的发展,砚的实用功能正在退化,而砚作为我国独有的一种工艺美术品,却越来越受到人们的关注。通过砚台的造型、雕饰等艺术特点,从粗与细、主与次、线与面、动与静、方与圆、刚与柔六个方面研究和探讨制砚艺术的规律性问题。     

Retraction and Generalized Extension of Computing With Words

Fuzzy automata, whose input alphabet is a set of numbers or symbols, are a formal model of computing with values. Motivated by Zadeh's paradigm of computing with words rather than numbers, Ying proposed a kind of fuzzy automata, whose input alphabet consists of all fuzzy subsets of a set of symbols, as a formal model of computing with all words. In this paper, we introduce a somewhat general formal model of computing with (some special) words. The new features of the model are that the input alphabet only comprises some (not necessarily all) fuzzy subsets of a set of symbols and the fuzzy transition function can be specified arbitrarily. By employing the methodology of fuzzy control, we establish a retraction principle from computing with words to computing with values for handling crisp inputs and a generalized extension principle from computing with words to computing with all words for handling fuzzy inputs. These principles show that computing with values and computing with all words can be respectively implemented by computing with words. Some algebraic properties of retractions and generalized extensions are addressed as well.     

矿井提升系统的强非线性振动

矿井提升机在提升重物的过程中,由于质量和刚度的变化引起的系统固有频率十分缓慢的变化,因此考虑钢绳质量的矿井提升机系统是一个慢变参数振动系统．本文首先应用Kuzmak—Luke的多尺度法得到有一般非线性弹性力的强非线性振动系统解的周期性条件及用Jacobi椭圆函数表示的平方非线性振动和立方非线性振动的首阶渐近解．其次,将得到的结果分别应用于有平方、立方非线性弹性力的质量慢变的矿井提升系统．最后,将理论结果应用于某个矿井提升系统,应用算例的渐近解和数值解的比较表明本方法是有效的．     

基于AOP技术的Composite模式的改进

Composite模式是解决部分与整体关系时常用的设计模式,但基于面向对象设计(OOP)所实现的Composite模式中存在的问题很难利用OOP解决。该文应用面向方面编程(AOP)改变类的行为,利用AspectJ实现Composite模式,通过与以OOP技术实现的Composite模式比较,得出应用AOP方法能够较好地实现责任分离,具有较高的可扩展性,模块结构更清晰。     

Numerical simulations of laser wakefield accelerators in optimal Lorentz frames

The simulation of laser wakefield accelerators with particle-in-cell codes in relativistic reference frames is described, with emphasis on the computational speed-ups, which may potentially exceed three orders of magnitude in comparison with laboratory frame configurations. The initialization of laboratory quantities in a relativistically moving frame is depicted, and the method for result comparison with the plasma rest frame is described. Benchmarks with laboratory frame simulations and experimental data where gains of ∼20 times were obtained are discussed, and potential numerical issues are analyzed. This method enables numerical simulations with shorter turnaround times required for parameter scanning, and for one-to-one three-dimensional experimental modeling of current and next generation laser wakefield experiments.     

Heart rate monitoring,activity recognition,and recommendation for e-coaching

Equipped with hardware, such as accelerometer and heart rate sensor, wearables enable measuring physical activities and heart rate. However, the accuracy of these heart rate measurements is still unclear and the coupling with activity recognition is often missing in health apps. This study evaluates heart rate monitoring with four different device types: a specialized sports device with chest strap, a fitness tracker, a smart watch, and a smartphone using photoplethysmography. In a state of rest, similar measurement results are obtained with the four devices. During physical activities, the fitness tracker, smart watch, and smartphone measure sudden variations in heart rate with a delay, due to movements of the wrist. Moreover, this study showed that physical activities, such as squats and dumbbell curl, can be recognized with fitness trackers. By combining heart rate monitoring and activity recognition, personal suggestions for physical activities are generated using a tag-based recommender and rule-based filter.     

独立于网格计算经济模型的记账和支付

针对当前网格计算经济中记账和支付的不足,提出了一种能够独立于计算经济模型的记账和支付体系结构.以独立的第3方完成记账数据采集;依据GSP和GSC的支付策略实现资源选择和支付;完成了一个支付算法,实现了和现实商业银行的仿真连接.     

基于压电陶瓷的不同服役年限木构件损伤监测

基于压电陶瓷的主动传感技术对不同服役年限的木构件进行损伤评估。取服役年限为0年、3年、40年的木构件制成三个尺寸相同的立方体试件,在每个试件的六个面上分别粘贴压电陶瓷片(PZT),用于信号的发射及接收。分别对不同服役年限试件传感器测量的信号进行了小波包和功率谱分析,发现应力波沿木材纵向传播时相较于服役年限短的试件,长年限试件的信号的幅值更大,沿木材径向及弦向传播时随木材服役年限的增加信号的幅值随之减小。结果表明,文中提出的方法能有效的识别不同服役年限的木构件,可为实际工程中不同服役年限木结构古建筑健康监测提供参考。     

PHP在Web数据库的应用研究

信息社会的到来,使昝ＷＥＢ技术与数据库技术紧密结合起来。该文着重对ＰＨＰ在ＷＥＢ数据库中的开发技术作了分析,并与其它ＷＥＢ数据库开发技术进行了比较,提出取Ｌｉｎｕｘ为系统平台,利用ＰＨＰ与ＭｙＳＱＬ构建民ＷＥＢ数据库系统的方案民,并对其前景作了展望。