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Handheld Devices (handheld + device)

Distribution by Scientific Domains

Information Science and Computing	40%

Selected Abstracts

Application of Visual Analytics for Thermal State Management in Large Data Centres

COMPUTER GRAPHICS FORUM, Issue 6 2010
M. C. Hao
I.3.3 [Computer Graphics]: Picture/Image Generation,Display Algorithms; H.5.0 [Information Systems]: Information Interfaces and Presentation,General Abstract Today's large data centres are the computational hubs of the next generation of IT services. With the advent of dynamic smart cooling and rack level sensing, the need for visual data exploration is growing. If administrators know the rack level thermal state changes and catch problems in real time, energy consumption can be greatly reduced. In this paper, we apply a cell-based spatio-temporal overall view with high-resolution time series to simultaneously analyze complex thermal state changes over time across hundreds of racks. We employ cell-based visualization techniques for trouble shooting and abnormal state detection. These techniques are based on the detection of sensor temperature relations and events to help identify the root causes of problems. In order to optimize the data centre cooling system performance, we derive new non-overlapped scatter plots to visualize the correlations between the temperatures and chiller utilization. All these techniques have been used successfully to monitor various time-critical thermal states in real-world large-scale production data centres and to derive cooling policies. We are starting to embed these visualization techniques into a handheld device to add mobile monitoring capability. [source]

Keynote paper: Unlocking the learning value of wireless mobile devices

JOURNAL OF COMPUTER ASSISTED LEARNING, Issue 3 2003
J. Roschelle
Abstract Many researchers see the potential of wireless mobile learning devices to achieve large-scale impact on learning because of portability, low cost, and communications features. This enthusiasm is shared but the lessons drawn from three well-documented uses of connected handheld devices in education lead towards challenges ahead. First, ,wireless, mobile learning' is an imprecise description of what it takes to connect learners and their devices together in a productive manner. Research needs to arrive at a more precise understanding of the attributes of wireless networking that meet acclaimed pedagogical requirements and desires. Second, ,pedagogical applications' are often led down the wrong road by complex views of technology and simplistic views of social practices. Further research is needed that tells the story of rich pedagogical practice arising out of simple wireless and mobile technologies. Third, ,large scale' impact depends on the extent to which a common platform, that meets the requirements of pedagogically rich applications, becomes available. At the moment ,wireless mobile technologies for education' are incredibly diverse and incompatible; to achieve scale, a strong vision will be needed to lead to standardisation, overcoming the tendency to marketplace fragmentation. [source]

Folded monopole antenna for handheld devices

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2010
Qinjiang Rao
Abstract This article presents a new multiband antenna for handheld devices. The antenna consists of three branches of folded monopoles, and it is designed to operate at most application bands used currently, such as GSM 850/900/1800/1900, UMTS2100, and WLAN 5GHz. The simulated and measured results validate the proposed design. The proposed antenna has better performances than other embedded antenna designs of the same maximum dimension. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 421,425, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24930 [source]

Advanced IMS client supporting secure signaling

BELL LABS TECHNICAL JOURNAL, Issue 4 2008
Ramana Isukapalli
With recent advances in core and access networks and the availability of increased bandwidth and sophisticated devices for end users, there is an increased demand for client applications running on mobile devices, such as laptops and handheld devices, to support real time applications like Voice over Internet Protocol (VoIP) and streaming video, apart from traditional applications like web browsing. This paper presents a prototype IP Multimedia Subsystem (IMS) client, which serves as a VoIP client to set up calls between Internet Protocol (IP) devices and interworks with circuit-switched networks to deliver calls to public switched telephone network (PSTN) phones. It implements supplementary services (including call waiting, call transfer, and call forwarding); supports multimedia ringing, short message service/multimedia messaging service (SMS/MMS), audio/video conferencing, and peer-to-peer video; and it can deliver a call to a user (as opposed to a device) by simultaneously ringing multiple devices registered by the user. Further, to address various security concerns, the client supports Hypertext Transfer Protocol (HTTP) digest authentication using Message Digest 5 (MD5) cryptographic function authentication and key agreement (AKA) and can create secure tunnels to the core network using IP security (IPsec). © 2008 Alcatel-Lucent. [source]