VoWLAN中的接纳控制策略研究

本文分析了连接接纳控制策略的相关内容并重点介绍了基于测量的接纳控制算法,提出了新的接纳控制算法来改善VoWLAN的QoS(Quality of Service)性能。该算法对应于不同的业务类型采用不同的时间窗阀值测量机制,根据负载的实时情况动态调整时间窗大小,从而可以改变系统的接纳性能,并提供相应的动态带宽分配机制,有效地保障VoWLAN系统的QoS需求。最后通过仿真实验对该算法进行了验证。     

基于WAP的移动学习模块

“教育无处不在，内容时刻更新”这是未来教育的人性化发展的方向。随着无线互联技术和无线终端的发展，继数字化学习之后出现了又一个新的学习模式——移动学习。文章中描述如何研究并实现一个移动学习系统，并能够通过无线移动设备访问教学和学习资源模块，从而通过新技术来改善教学、学习和管理。     

Effects of Mobile Phones on Children's and Adolescents’ Health: A Commentary

The use of digital technology has grown rapidly during the last couple of decades. During use, mobile phones and cordless phones emit radiofrequency (RF) radiation. No previous generation has been exposed during childhood and adolescence to this kind of radiation. The brain is the main target organ for RF emissions from the handheld wireless phone. An evaluation of the scientific evidence on the brain tumor risk was made in May 2011 by the International Agency for Research on Cancer at World Health Organization. The scientific panel reached the conclusion that RF radiation from devices that emit nonionizing RF radiation in the frequency range 30 kHz–300 GHz is a Group 2B, that is, a “possible” human carcinogen. With respect to health implications of digital (wireless) technologies, it is of importance that neurological diseases, physiological addiction, cognition, sleep, and behavioral problems are considered in addition to cancer. Well‐being needs to be carefully evaluated as an effect of changed behavior in children and adolescents through their interactions with modern digital technologies.     

Diffusion of innovations: Smartphones and wireless anatomy learning resources

The author has previously reported on principles of diffusion of innovations, the processes by which new technologies become popularly adopted, specifically in relation to anatomy and education. In presentations on adopting handheld computers [personal digital assistants (PDAs)] and personal media players for health sciences education, particular attention has been directed to the anticipated integration of PDA functions into popular cellular telephones. However, limited distribution of early “smartphones” (e.g., Palm Treo and Blackberry) has provided few potential users for anatomical learning resources. In contrast, iPod media players have been self‐adopted by millions of students, and “podcasting” has become a popular medium for distributing educational media content. The recently introduced Apple iPhone has combined smartphone and higher resolution media player capabilities. The author successfully tested the iPhone and the “work alike” iPod touch wireless media player with text‐based “flashcard” resources, existing PDF educational documents, 3D clinical imaging data, lecture “podcasts,” and clinical procedure video. These touch‐interfaced, mobile computing devices represent just the first of a new generation providing practical, scalable wireless Web access with enhanced multimedia capabilities. With widespread student self‐adoption of such new personal technology, educators can look forward to increasing portability of well‐designed, multiplatform “learn anywhere” resources. Anat Sci Ed 1:233–239, 2008. © 2008 American Association of Anatomists.     

Transforming the twenty-first-century campus to enhance the net-generation student learning experience: using evidence-based design to determine what works and why in virtual/physical teaching spaces

The twenty-first century has seen the rapid emergence of wireless broadband and mobile communications devices which are inexorably changing the way people communicate, collaborate, create and transfer knowledge. Yet many higher education campus learning environments were designed and built in the nineteenth and twentieth centuries prior to wireless broadband networks. Now, new learning environments are being re-engineered to meet these emerging technologies with significant challenges to existing pedagogical practices. However, these next generation learning environments (NGLEs) have not been evaluated thoroughly to see if they actually work as they are scaled up across the higher education system. Whilst there have been a range of NGLEs designed globally – with Australia leading in the past five years or so – it is timely that a more rigorous research methodology drawing from health facility evidence-based design is taken to evaluate their effectiveness in improving the student experience and learning outcomes.     

基于GPIB-ENET可移动实验测量技术

本科教学中部分地采用现代化仪器设备促进了层次化实验课程改革,结合使用计算机测控与数据采集处理有助于实验结果定量分析。充分发挥智能仪器的教学使用效率,才能既有效地控制成本又满足教育资源优化的实验室建设要求。基于通用仪器接口功能和GPIB-ENET接口转换器件,采用无线网络接入技术实现实验室内智能仪器可移动测量使用,从而进一步提高设备资源共享的教学可操作性。     

便携式人体生命指征监测系统研发

针对人们的需求,开发出了用于社区或家庭健康监护的小型化装置,该装置分别采集人体生理信号与参数（如心电信号）,经由无线短距离通信技术,传送到无线移动终端（如掌上电脑、PDA或手机）.系统在无线移动终端上可实现健康监护参数的数据存储、显示和信息处理,并基于其无线数据通信功能实现联网,构建低成本健康监护网络,实现远程健康监护.     

PoE交换机设计与配置管理

在WLAN业务和安防网络视频监控业务中需部署大量无线AP和IP Camera设备,为解决部署在特殊位置上设备取电问题,可通过PoE技术进行远程供电。结合成熟的网络交换机技术,PoE交换机随之出现。通过介绍PoE交换机设计与配置,进一步加深对PoE技术的认识。这种设计和配置的PoE交换机已在市场上成功应用。     

Education,technology, and individual privacy

The right to privacy is based on a belief in the essential dignity and worth of the individual. Modern technological devices, along with advances in the behavioral sciences, can threaten the privacy of students. Fortunately, invasions of privacy in education have not been widespread. However, sufficient violations have been noted to warrant specific legislation and to promote a sharp increase in attention to procedures that will ensure protection of individual privacy. Technology that can reveal innermost thoughts and motives, or can change basic values and behaviors, must be used judiciously and only by qualified professionals under strictly controlled conditions. Education involves individuals, and educational experimentation is human experimentation. The educator must safeguard the privacy of students and their families. Grayson (1976) for a discussion of the implication of widescale adoption of instructional technology for maintaining diversity in education.     

幼儿园无线竞赛抢答系统的设计

为方便幼儿园进行数学竞赛,巩固和加强小朋友对初级数学运算技能的理解,设计了一套幼儿园无线竞赛抢答系统,能够实现多人抢答功能。该系统以单片机为核心,包括无线竞赛控制器和无线竞赛手持器,由NRF24L01无线数传模块实现上、下位机之间的通信连接,同时采用LabVIEW编程完成上位机界面的设计,在此界面上可进行设置比赛题目、加减分数值、设定比赛倒计时、控制比赛进程、显示抢答结果等操作,满足了幼儿园数学竞赛时对抢答系统的要求。     

Long-term follow-up of children conceived through assisted reproductive technology

Children conceived via assisted reproductive technologies (ART) are nowadays a substantial proportion of the population. It is important to follow up these children and evaluate whether they have elevated health risks compared to naturally conceived (NC) children. In recent years there has been a lot of work in this field. This review will summarize what is known about the health of ART-conceived children, encompassing neonatal outcomes, birth defects, growth and gonadal developments, physical health, neurological and neurodevelopmental outcomes, psychosocial developments, risk for cancer, and epigenetic abnormalities. Most of the children conceived after ART are normal. However, there is increasing evidence that ART-conceived children are at higher risk of poor perinatal outcome, birth defects, and epigenetic disorders, and the mechanism(s) leading to these changes have not been elucidated. Continuous follow-up of children after ART is of great importance as they progress through adolescence into adulthood, and new ART techniques are constantly being introduced.     

智能多媒体教室上位机控制系统的设计

在基于无线通信方式控制的智能多媒体教室系统中,有两种控制设备工作的方式：一种是遥控器（键盘）控制;一种是上住机控制,本文介绍上住机控制系统的设计方案。在上住机上设计控制代码,然后通过串口进行计算机与单片机之间的通信,单片机与工作设备之间通过无线通信方式进行控制,从而实现了上位机与工作设备之间的无线通信。     

无线网络在校园网中的应用

校园无线网络较传统有线网络具有无缝覆盖、易扩展、维护费用低、移动灵活的优势。校园无线网络应用在室内场所和室外场所。建设校园无线网络时,主要考虑无线网络覆盖和无线网络应用范围。考虑到网络扩展的要求,校园无线网络系统应保证其安全性、移动性以及与有线的无缝连接。强大的数据加密与安全的认证方式并不能确保无线网络的绝对安全,网络管理人员也要提高安全防范意识,加强网络用户的管理与监控。只有做到无线网络与有线网络的完美结合,相互弥补缺陷,才能使整个网络系统更加完善。     

泛在移动环境下学生对移动学习项目的反馈

本文总结了俄克拉荷马基督教大学移动学习项目试点一学期后学生的反馈问卷.该学校在美国是最早给学生配发笔记本电脑和智能手机或iPod Touch双重移动设备的学校之一,全校覆盖无线网络.该问卷调查试图了解在如此泛在的网络使用环境下,学生使用移动学习工具和环境的使用习惯及期待.问卷结果显示:整体来说,学生认为这种泛在学习环境对其学习有利;学生使用移动设备主要用于辅助学习、效率改进、信息获取、沟通和娱乐,这些都是学生在校整体学习体验中值得关注的地方.移动设备的更多用途还有待澄清、宣传、演示、培训、支持.此问卷还显示学校和研究者应考虑移动学习项目可支持的多种学习方式和因学习者而异的多种教育用途.     

基于物联网和ZigBee的智能家居系统设计

利用物联网和ZigBee技术设计了一个智能家居系统,使家居常用的分立设备通过无线网络进行组网、通信,构成一个相互联系、协同操作的整体,实现家居环境参数监控、防盗自动报警、火灾自动报警、燃气泄漏报警等,给用户带来最大程度的高效、便利、舒适与安全。     

Exploring processes and outcomes of wireless internet in higher education: a case study of a university’s early experience

Many universities in the UK have recently started offering their staff and students free wireless Internet access through Wireless Local Area Network (WLAN) technologies, such as Wi‐Fi. Based on a small empirical study of WLAN deployment in a university setting, the article explores adoption processes of the new technology by both the organisation and individuals, and considers factors behind the decision to offer wireless and how students as well as teachers appear to have responded so far. Despite technologists’ enthusiasm for the new learning opportunities created by the technology, wireless availability does not appear to result in, or be linked to, a coherent m‐learning strategy. Furthermore, the findings suggest that too little attention has been paid to understanding students’ social contexts of use and attitudes towards the technology, which are seen as pivotal to the development of wireless pedagogical uses.     

The impact of wireless keypads in an interprofessional education context with health science students

The aim of this study was to identify if wireless keypads could facilitate interprofessional interaction among undergraduate paramedic, nursing, occupational therapy, physiotherapy, health science, social work and midwifery students. Secondary research aims included the examination of students' perceptions of interprofessional education and how students perceived using wireless keypads in large lecture classes and smaller tutorials. The study used a mixed methodology approach via self‐reporting questionnaires and focus groups that included (n = 210) students in week 1 and (n = 151) students in week 13 of an undergraduate unit. Overall, students were satisfied with the use of wireless keypads in their interprofessional undergraduate unit of study. While modest findings supported the use of wireless keypads in improving student interaction, other findings were statistically significant in understanding the roles of other health professions and why collaboration in health‐care environments was important for professional growth. The following themes emerged from the qualitative data: engagement, satisfaction, use of educational technology, interprofessional education and learning environment. Integration of wireless keypads has assisted undergraduate students to better appreciate and understand other health‐care disciplines within an interprofessional education setting. Students reported that they appreciated the alternative teaching and learning approach that wireless keypads offered, thus improving engagement and interactivity, and providing a broader understanding of other allied health‐care professions.     

ZigID: Improving visibility in industrial environments by combining WSN and RFID

The objective of this work is to provide decision-making processes with an updated/real picture of the mobile resources in industrial environments through a constant feedback of information. The combination of identification technologies and wireless sensor networks (WSN) is proposed as a key development to guarantee an accurate and timely supply of online information regarding the localization and tracking of the mobile wireless devices. This approach uses a cooperative and distributed localization system, called ZigID, which is a WSN based on a Zigbee network with radio frequency identification (RFID) active tags as end nodes. The WSN can recover not only the ID information stored at the tags attached to mobile resources, but also any other useful data captured by specific sensors for acceleration, temperature, humidity and fuel status. This paper also shows the development of ZigID, including devices and information flows, as well as its implementation in ground handling operations at the Ciudad Real Central Airport, Spain.     

用于精密控制的直线磁通切换永磁电动机的暂态性能分析

提出了一种适用于精密控制的新型直线磁通切换永磁(LFSPM)电机的动态dq数学模型.通过采用有限元法对LFSPM原型机进行数值仿真,分析该电机的运行原理并计算其反电动势、磁链等电磁参量.仿真和测量表明,该电机的反电动势和磁链均按正弦规律变化,并且在运行时具有与直线表面永磁电机(LSPM)相似的磁链变化规律.在此基础上,...     

An embedded packet train and adaptive FEC scheme for effective video adaptation over wireless broadband networks

INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a…