4,259 research outputs found
In-body path loss models for implants in heterogeneous human tissues using implantable slot dipole conformal flexible antennas
Get PDFA wireless body area network (WBAN) consists of a wireless network with devices placed close to, attached on, or implanted into the human body. Wireless communication within a human body experiences loss in the form of attenuation and absorption. A path loss model is necessary to account for these losses. In this article, path loss is studied in the heterogeneous anatomical model of a 6-year male child from the Virtual Family using an implantable slot dipole conformal flexible antenna and an in-body path loss model is proposed at 2.45 GHz with application to implants in a human body. The model is based on 3D electromagnetic simulations and is compared to models in a homogeneous muscle tissue medium
Building Programmable Wireless Networks: An Architectural Survey
Full text linkIn recent times, there have been a lot of efforts for improving the ossified
Internet architecture in a bid to sustain unstinted growth and innovation. A
major reason for the perceived architectural ossification is the lack of
ability to program the network as a system. This situation has resulted partly
from historical decisions in the original Internet design which emphasized
decentralized network operations through co-located data and control planes on
each network device. The situation for wireless networks is no different
resulting in a lot of complexity and a plethora of largely incompatible
wireless technologies. The emergence of "programmable wireless networks", that
allow greater flexibility, ease of management and configurability, is a step in
the right direction to overcome the aforementioned shortcomings of the wireless
networks. In this paper, we provide a broad overview of the architectures
proposed in literature for building programmable wireless networks focusing
primarily on three popular techniques, i.e., software defined networks,
cognitive radio networks, and virtualized networks. This survey is a
self-contained tutorial on these techniques and its applications. We also
discuss the opportunities and challenges in building next-generation
programmable wireless networks and identify open research issues and future
research directions.Comment: 19 page
Developing Teachers’ Professional Learning: Canadian Evidence and Experiences in a World of Educational Improvement
Get PDFThis article discusses the current international emphasis on educational improvement and, particularly, approaches to developing teachers’ professional learning. I begin by arguing for the importance of Canadian narratives and evidence within global debates. I turn then to an example of a recently conducted study of the state of educators’ professional learning in Canada to examine research-informed principles and examples from policies and practices across Canada. I conclude by arguing for the importance of the Canadian education community learning with, from, and for Canada, appreciating that diversity is our strength, but recognizing that inequities are our greatest challenge
Active congestion control using ABCD (available bandwidth-based congestion detection).
Get PDFWith the growth of the Internet, the problem of congestion has attained the distinction of being a perennial problem. The Internet community has been trying several approaches for improved congestion control techniques. The end-to-end approach is considered to be the most robust one and it has served quite well until recently, when researchers started to explore the information available at the intermediate node level. This approach triggered a new field called Active Networks where intermediate nodes have a much larger role to play than that of the naive nodes. This thesis proposes an active congestion control (ACC) scheme based on Available Bandwidth-based Congestion Detection (ABCD), which regulates the traffic according to network conditions. Dynamic changes in the available bandwidth can trigger re-negotiation of flow rate. We have introduced packet size adjustment at the intermediate router in addition to rate control at sender node, scaled according to the available bandwidth, which is estimated using three packet probes. To verify the improved scheme, we have extended Ted Faber\u27s ACC work in NS-2 simulator. With this simulator we verify ACC-ABCD\u27s gains such as a marginal improvement in average TCP throughput at each endpoint, fewer packet drops and improved fairness index. Our tests on NS-2 prove that the ACC-ABCD technique yields better results as compared to TCP congestion control with or without the cross traffic. Source: Masters Abstracts International, Volume: 43-03, page: 0870. Adviser: A. K. Aggarwal. Thesis (M.Sc.)--University of Windsor (Canada), 2004
Social and Cultural Dimensions of Market Expansion
Get PDFWe have identified three dimensions of market expansion: the growth of market oriented production and trade, internal and external market integration and the creation of virtual markets. These three processes can occur side by side and are connected with social and cultural change.markets culture market expansion
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