Assessing the use of hearing protection in industrial settings: A comparison between methods

In industrial environments, hearing protection devices (HPDs) are used to protect workers from noise exposure. However, the effectiveness of this practice can be compromised when workers periodically remove their HPDs while exposed to noise, which greatly affects the attenuation of the devices. Therefore, it is important for techniques that assess the “real” use of HPDs to be accurate. This study analysed the accuracy and reliability of three HPD assessment methods: (1) the self-reported use, (2) the use of a statistical sampling observation method and (3) the use of video to monitor (record) all of the workers' activity. The studied techniques were applied in an industrial environment where 2 types of HPDs are used and where wearing HPDs is compulsory. The results demonstrated that self-reported data differ from the observed workers' behaviour and that workers tend to overestimate their use of the HPDs. From the analysed variables, it can be concluded that the self-reported data are more reliable for older workers and for those with greater experience in using HPDs. Accordingly, it can be concluded that the self-reported use of HPDs is a good, practical method, particularly in terms of the time-effectiveness, cost and accuracy of the technique.     

矿用综合保护装置在用检测技术现状及发展

指出中国矿用综合保护装置在用检测技术存在标准可操作性差、综合保护装置种类及型号繁多且更新快等问题;从矿用综合保护装置的发展历程和通用检测装备特点方面阐述了中国矿用综合保护装置在用检测技术的现状,并提出了中国矿用综合保护装置在用检测技术的发展方向,即提高检测精度与自动化程度、具有更强的故障分析能力、更具环保性、计算机和检测系统更紧密结合、智能BIT技术与标准化。     

一种基于模糊监督协调控制的保护装置测试方法

机车保护装置种类繁多, 测试时需要提供各种波形的大电流, 且要求电流具有特定的脉动, 现有的测试设备已难以满足测试与故障诊断要求。针对测试对象多样、时变, 常规控制方法难以实现的状况, 提出基于模糊监督协调控制的系统控制策略。设计自适应PID相位控制器对恒流或曲线模式下的相位进行控制, 配合神经网络控制器在线学习, 实现准确快速的控制。测试系统的实际投入使用与专家技术鉴定表明, 该方法有效地提高了测试效率与准确性。     

PG数字式保护测控装置的设计

为了保障低压电网及厂用电系统的安全稳定运行,提出了基于网络版图形化保护测控装置的设计方案.结合PG系列保护测控装置的设计需求,详细分析了其关键技术和主要功能模块,设计并完成了该装置的图形化上位机软件和基于MPC8247 CPU及Vxworks相结合的下位机程序,它定时地采集测控现场的保护数据,直观地展现了装置的各种软硬...     

新型电力系统保护测控装置硬件平台的研制

提出一种基于单CPU以及外围电路的新型保护测控装置的硬件平台,克服了多CPU结构硬件平台成本高、开发周期长以及维护不方便的缺点,能够满足电力系统中低压保护测控装置性能和成本的综合需求,实现了此类产品性价比的平衡。介绍了在此硬件平台上移植各种继电保护的原理和算法,开发多种电力系统保护测控装置的方案,以及相应的各模块插件的配置。     

某矿区变电站进线段防雷改造措施及仿真分析

介绍了某矿区110kV变电站线路防雷措施的基本情况,分析了该变电站35kV进线段遭受雷击的原因,即线路绝缘水平遭人为提高后与站内绝缘水平等级不匹配和进线段杆塔接地电阻过高,并提出了相应的采用加装绝缘子保护间隙配合避雷器进行差异性保护和采用树枝状接地装置的改造措施。ATPEMTP仿真分析结果验证了改造措施的可行性。     

Directional localization in high ambient noise with and without the use of hearing protectors

Personal hearing protective devices (HPDs) are becoming increasingly common in settings where levels of noise above 85 dB(A) represent a potential threat to hearing. Several previous studies have indicated that the use of such devices adversely affects the localization of sounds, but none of these experiments employed very precise measures of location discriminability. The major study in the present report examined just such fine discrimination, using a forced-choice task, and compared the effects of three different HPDS. Localization signals were 1.5 s bursts of noise (≥ 1 kHz). Both of the described experiments were conducted in acoustically complex, reverberant environments, to simulate real working conditions. Results indicated that greater attenuation (especially at higher frequencies) was the primary factor associated with poor performance on the fine discrimination task.     

面向移动终端的隐私数据安全存储及自毁方案

针对移动终端隐私数据的安全问题,结合数据压缩、门限秘密共享和移动社交网络,提出一种面向移动终端的隐私数据安全存储及自毁方案.首先,对移动隐私数据进行无损压缩获得压缩数据.然后,使用对称密钥对压缩数据进行对称加密获得原始密文.接着,将原始密文分解成两部分密文块:其中一部分密文块与时间属性结合并封装成移动数据自毁对象(MDSO)后保存到云服务器中;另一部分密文块与对称密钥和时间属性结合,再经过拉格朗日多项式处理后获得密文分量.最后,将这些密文分量分别嵌入图片并共享到移动社交网络.当超过授权期后,任何用户都无法获取密文块重组出原始密文,从而无法恢复隐私数据,最终实现移动隐私数据的安全自毁.实验结果表明:当文件为10 KB时,压缩和加密时间之和仅为22 ms,说明所提方案性能开销较低.综合分析亦表明该方案具备较高安全性,能有效抵抗安全攻击,保护移动隐私数据的隐私安全.     

2011年贵州电网220kV及以上继电保护装置运行评价

按照“南方电网公司输变电设备状态评价标准”和“贵州电网设备运行状况分析管理工作标准”的要求,对各供电局上报的2010年10月～2011年9月设备运行评价数据进行计算分析,本次以继电保护装置为例进行运行评价分析。     

Effects of text input methods on performance in operating handheld devices between young and elderly users

This study investigated the effect of age (elderly and young participants), input methods (keyboard and handwriting), and input tools (finger and stylus) on participants’ performance in operating handheld devices. The correct ratio and execution time for device operation served as the criteria for performance evaluation. The study results revealed that the interaction between age, input method, and input tool had a significant effect on the participants’ correct ratio in operating handheld devices. For young participants, only the input method had a significant effect on the correct ratio. The keyboard provided superior results to handwriting. For the elderly participants, the interaction between input method and input tool had a significant effect on the correct ratio. When the input method was handwriting, the input tool had a significant effect on the correct ratio. Specifically, the stylus provided superior results to the finger. However, when a keyboard was used, the input tool had no significant effect on the elderly participants’ correct ratio. Concerning execution time, the interaction between age and input method had a significant effect on performance. For the young participants, the input method had a significant effect on the execution time. Specifically, the keyboard provided superior results to handwriting. However, for the elderly participants, the input method had no significant effect on the execution time.     

Information presentation in small screen devices: The trade-off between visual density and menu foresight

Small mobile devices are ubiquitous and must be designed with great care. One of the most serious challenges is how information on the small displays is presented optimally. This paper addresses the special problem of the increasing number of aged users. On the one hand, information displayed should be easily readable. This requires a low information density and a sufficiently large font size. On the other hand menu orientation is facilitated when the amount of information per screen is maximized and a large preview is allowed. This requires presenting as many functions as possible on the screen at a time. Thus, the tradeoff between readability and orientation demands is crucial. In the present study, this tradeoff was experimentally investigated. Two factors, font size (8 pt, 12 pt) and the size of the preview (one or five functions per screen at a time) were varied and effects on navigation performance were observed. Forty older participants solved nine common phone navigation tasks twice consecutively on a simulated mobile phone. Both factors contributed to performance, but there was a significant interaction: navigation performance was optimal when font size and the size of the preview were large. The lowest performance was obtained when the preview was small and the font size large, showing that proper orientation is more important than visibility demands. The results can be used in ergonomic guidelines to optimized information presentation on small screens.     

Functional relationship between cathodic protection current/potential and duration of system deployment in desert conditions

In this paper we analyze functional correlation of the attenuation of protection current/potential in cathodic protection (CP) systems over the time. Our aim is to define protection current/potential function in correlation to CP system exploitation time, based on long term measurements of the current/potential. Correlation of the attenuation of the protective current/potential over the time period is established by comparison of the experimental data and data obtained from our analytical model. The analytical model allows prediction of the changes in the changes in the current/potential over the time and thus prediction and verification of the CP. Our data are collected for cathodic protection PCCP (Prestressed Concrete Cylinder Pipe) in desert conditions. Usage of our model for the attenuation of protective current/potential over time of exploitation of a CP system significantly simplifies operational procedures and saves on time, equipment and measurements. Application of proposed mathematical model, make it is possible, without long-lasting measurements, reliably envisage evolution in time of a cathodic protection system.