Effects of a vertical keyboard design on typing performance, user comfort and muscle tension

To circumvent the awkward pronated hand position inherent to conventional horizontal keyboards, a vertical, split keyboard was designed with flexible cushions supporting the wrists, allowing relaxed hand and arm postures. During eight twice-weekly 30-min training sessions, the performance and subjective comfort of nine experienced typists were tested. Typing speed and error percentage, and surface electromyographic activity of six forearm muscles and two postural muscles were recorded in separate sessions at the end of each week. Typing speed rapidly recovered to the preset rate of 300 keystrokes/min and error percentages were similar for the two keyboards. The vertical keyboard caused lower muscular activity in especially finger extensor muscles, did not increase postural muscle activity, and self-reported comfort was higher. Thus, the vertical keyboard was easily mastered, was experienced as comfortable, and caused less stress on muscles sensitive to repetitive strain injuries.     

车载智能充电器的设计与实现

设计一款车载智能充电器,根据电池容量、当前电压值及电池温度调节充电电流、充电电压及充电时间;并通过充电器闭环拓扑反馈系统实时评估电池状态、对充电流程及模式进行动态调整,确保充电最优化及效率最大化。文章根据车载电池使用说明及充电需求,提出一种智能充电流程,并重新设计工作模式与功能,对充电器的软件及硬件系统进行探索开发。实验结果表明智能充电器不仅可提高充电效率,对电池的寿命维护及安全使用都有巨大改善。     

独立、并网双模式户用光伏发电装置的研究与设计

针对户用光伏发电系统的特点和要求进行了系统的研究与设计。系统设计将独立逆变与并网逆变相结合,使系统既可以工作在独立逆变状态,为负载提供正弦交流电源,也可以工作在并网逆变状态,将太阳的能量或蓄电池的能量回馈到电网。本系统采用TI公司32位定点DSP芯片TMS320F2812为控制核心,利用PIC16F877A单片机构成系统的人机操作界面。本文所设计的系统具有完善的保护功能、键盘监控和液晶显示、串口通讯功能,为家庭使用提供了方便。实验结果验证了方案的可行性。     

离散时间系统的滑模控制器设计与仿真研究

针对不确定性离散时间系统,分析和设计了一类变结构控制器。当存在外界干扰和不确定性时,系统状态也是全局有界稳定的。一个新的切换面作为系统的输出信号被提出,特别用来设计滑模控制器。系统状态一旦进入到准滑动模态,就对设备参数变化和外界干扰显示出强的鲁棒性,因为控制器的设计完全考虑了边界层的影响。外推法被用来估计不确定离散时间系统的不确定值。两种方法均有效地消除了系统的抖振,确保了系统的稳定性,且保证了变结构控制系统良好的品质。最后,仿真结果证实了所提出方法的有效性。     

Cryptanalysis and improvement on two efficient remote user authentication scheme using smart cards

In 2002, Chien et al. proposed an efficient remote authentication scheme using smart cards, in which only few hashing operations are required. Later, Ku et al. gave an improved scheme to repair the security pitfalls found in Chien et al.'s scheme. Also Yoon et al. presented an enhancement on Ku et al.'s scheme. In this paper, we show that both Ku et al.'s scheme and Yoon et al.'s scheme are still vulnerable to the guessing attack, forgery attack and denial of service (DoS) attack. In addition, their schemes lack efficiency when users input wrong passwords. To remedy these flaws, this paper proposes an efficient improvement over Ku et al.'s and Yoon et al.'s schemes with more security. The computation cost, security, and efficiency of the improved scheme are embarking for the real application in the resource-limited environment.     

Predicting user preferences of environment design: a perceptual mechanism of user interface customisation

It is a well-known fact that users vary in their preferences and needs. Therefore, it is very crucial to provide the customisation or personalisation for users in certain usage conditions that are more associated with their preferences. With the current limitation in adopting perceptual processing into user interface personalisation, we introduced the possibility of inferring interface design preferences from the user’s eye-movement behaviour. We firstly captured the user’s preferences of graphic design elements using an eye-tracker. Then we diagnosed these preferences towards the region of interests to build a prediction model for interface customisation. The prediction models from eye-movement behaviour showed a high potential for predicting users’ preferences of interface design based on the paralleled relation between their fixation and saccadic movement. This mechanism provides a novel way of user interface design customisation and opens the door for new research in the areas of human–computer interaction and decision-making.     

Analysis and design of a smart card based authentication protocol

Numerous smart card based authentication protocols have been proposed to provide strong system security and robust individual privacy for communication between parties these days. Nevertheless, most of them do not provide formal analysis proof, and the security robustness is doubtful. Chang and Cheng （2011） proposed an efficient remote authentication protocol with smart cards and claimed that their proposed protocol could support secure communication in a multi-server environment. Unfortunately, there are opportunities for security enhancement in current schemes. In this paper, we identify the major weakness, i.e., session key disclosure, of a recently published protocol. We consequently propose a novel authentication scheme for a multi-server envi- ronment and give formal analysis proofs for security guarantees.     

Comparison of a touch-sensitive VDU and computer-aided keypad for plant control

The technology of touch screens is discussed with emphasis on the development of appropriate software and human factors. A touch screen was compared with an intelligent keypad in an experiment in which CEGB personnel controlled simulated plant. Users preferred the touch screen in normal conditions and particularly for emergency working. Also, a statistically significant improvement in plant controllability was recorded when the touch screen was used in place of the keypad. Touch screens are seen to possess many advantages over conventional man-machine interfaces. Their use is shown to be appropriate in applications suchas alarm analysis, data and mimic selection and interactive graphics as well as for controlling plant.     

基于PID控制LLC微波电源的仿真研究

研制了一款基于PID控制输出电压的高频软开关电源。主电路采用了倍压整流输出LLC谐振变换器,利用PID控制闭环电压反馈,并通过对谐振变换器的特性分析绘制了直流增益曲线。根据理论分析与计算并结合实际调试情况,对LLC微波电源的主要参数进行设计,得到的仿真实验结果验证了分析计算的正确性。     

Developing a smart multifunctional outdoor jacket with wearable sensing technology for user health and safety

Multimedia Tools and Applications - Over the decades, there has been a sustained effort to use fashion as a medium for delivering digital functionality. The goal is to integrate information...     

The influence of design aesthetics in usability testing: Effects on user performance and perceived usability

This article examined the effects of product aesthetics on several outcome variables in usability tests. Employing a computer simulation of a mobile phone, 60 adolescents (14-17 yrs) were asked to complete a number of typical tasks of mobile phone users. Two functionally identical mobile phones were manipulated with regard to their visual appearance (highly appealing vs not appealing) to determine the influence of appearance on perceived usability, performance measures and perceived attractiveness. The results showed that participants using the highly appealing phone rated their appliance as being more usable than participants operating the unappealing model. Furthermore, the visual appearance of the phone had a positive effect on performance, leading to reduced task completion times for the attractive model. The study discusses the implications for the use of adolescents in ergonomic research.     

一种智能家居远程控制系统的硬件设计

设计智能的可远程控制的家居控制系统,采用STC89C51RC、STC89C58RD和STC2052AD作为微控制器,通过nRF24L01提供的2.4 GHz无线连接,实现各部分之间的通信,以智能化控制家用电器,并通过TC35提供的SMS接口,实现了通过移动终端远程控制家里电器的功能.     

Tool design, user characteristics and performance: a case study on plate-shears

Performance, grip forces and fatigue were studied in six male and six female subjects while cutting with plate-shears. Three types of plate-shears were used, one standard and two modified, either with a spring grip, or with a spring grip in combination with a reduced grip span. In addition, three types of plate - easy, moderately difficult and difficult to cut - were used. Male subjects used around 40% of their maximal grip force and female subjects around 60% with the moderately difficult plate; the male subjects produced more than twice as long a cutting distance as the females. Neither EMG analysis (frequency shifts) nor subjective exertion or reduction of handgrip MVC indicated a more pronounced fatigue in women than in men, probably because the female subjects used about a 50% lower cutting rate than the men. Productivity (in cm cut per min) was strongly related to measures of hand size and to the relative grip force used. Thus in a multiple regression analysis using metacarpal hand circumference and relative grip force as independent variables, R2 was 0.77. The two types of modified plate-shears were preferred by all and gave a roughly 30% higher productivity in the male subjects but did not improve productivity in the females. However, with a spring grip and reduced grip span, the female subjects reduced the relative grip forced used from around 65 to 50%. The total work (force-time integral) per cm cut was not influenced by type of plate-shear.     

智能卡芯片操作系统的研究与实现

为了充分利用智能卡芯片有限的资源,开发出高效的、易扩充的芯片操作系统(COS),研究了智能卡COS设计和实现方法.介绍了智能卡COS的体系结构,设计了结构模型,从COS的主守护流程、通信管理、文件系统、安全管理和命令解释5个方面论述了智能卡COS的设计与实现.采用中断调度方式节省了系统开销,采用静态存储管理方式节约了存储空间.通过测试验证了COS符合国际标准和行业标准,该系统能正确应用在终端和相应网络环境中,具有良好的兼容性和稳定性.     

基于嵌入式系统的Motif图形界面开发技术研究

针对应用于国防领域的国内某特种车辆对显控系统的具体功能需求,讨论了在嵌入式实时操作系统vxWorks的基础上利用Motif库作为工具开发图形用户界面的相关技术。从建立基于Tornado的嵌入式应用软件交叉开发环境入手,总结出了X Window／Motif程序接口及其代码的调试框架,研究了在嵌入式图形用户界面实际开发过程中所遇到的具体技术难题,并通过解决这些技术问题,最终实现了对VxWorks在图形用户界面开发方面的功能扩展。     

改进OCB认证功能的工作模式

针对具有认证加密功能的OCB模式在单个密钥下处理大容量的数据时容易产生碰撞,降低其认证功能这一缺陷,提出对OCB认证功能校验和的生成方式的改进方案,降低了在碰撞发生时丢失认证功能的概率,在不改变原方案中速度快、效率高等优势的前提下,提高了OCB模式认证功能在碰撞发生时的安全性。     

基于DSP和CPLD的智能相机系统设计与研制

嵌入式实时图像处理技术是目前结合图像处理、模式识别、传感器以及微电子等多学科门类的一门前沿技术。在电子技术迅猛发展的推动下,嵌入式实时图像处理也成为可能。在目前的电子技术条件下,作者结合DSP技术、CPLD/FPGA技术,以及图像处理技术、传感器技术等,开发设计出一种实用的嵌入式实时图像处理系统——工业用智能相机,实现了产品质量的自动检测和分类。