2 resultados para Connectivity
em QSpace: Queen's University - Canada
Resumo:
“Red coats and wild birds: military culture and ornithology across the nineteenth-century British Empire” investigates the intersections between British military culture and the practices and ideas of ornithology, with a particular focus on the British Mediterranean. Considering that British officers often occupied several imperial sites over the course of their military careers, to what extent did their movements shape their ornithological knowledge and identities at “home” and abroad? How did British military naturalists perceive different local cultures (with different attitudes to hunting, birds, field science, etc.) and different local natures (different sets of birds and environments)? How can trans-imperial careers be written using not only textual sources (for example, biographies and personal correspondence) but also traces of material culture? In answering these questions, I centre my work on the Mediterranean region as a “colonial sea” in the production of hybrid identities and cultural practices, and the mingling of people, ideas, commodities, and migratory birds. I focus on the life geographies of four military officers: Thomas Wright Blakiston, Andrew Leith Adams, L. Howard Lloyd Irby, and Philip Savile Grey Reid. By the mid-nineteenth century, the Mediterranean region emerged as a crucial site for the security of the British “empire route” to India and South Asia, especially with the opening of the Suez Canal in 1869. Military stations served as trans-imperial sites, connecting Britain to India through the flow of military manpower, commodities, information, and bodily experiences across the empire. By using a “critical historical geopolitics of empire” to examine the material remnants of the “avian imperial archive,” I demonstrate how the practices and performances of British military field ornithology helped to: materialize the British Mediterranean as a moral “semi-tropical” place for the physical and cultural acclimatization of British officers en route to and from India; reinforce imperial presence in the region; and make “visible in new ways” the connectivity of North Africa to Europe through the geographical distribution of birds. I also highlight the ways in which the production of ornithological knowledge by army officers was entwined with forms of temperate martial masculinity.
Resumo:
Dense deployment of wireless local area network (WLAN) access points (APs) is an important part of the next generation Wi-Fi and standardization (802.11ax) efforts are underway. Increasing demand for WLAN connectivity motivates such dense deployments, especially in geographical areas with large numbers of users, such as stadiums, large enterprises, multi-tenant buildings, and urban cities. Although densification of WLAN APs guarantees coverage, it is susceptible to increased interference and uncoordinated association of stations (STAs) to APs, which degrade network throughput. Therefore, to improve network throughput, algorithms are proposed in this thesis to optimally coordinate AP associations in the presence of interference. In essence, coordination of APs in dense WLANs (DWLANs) is achieved through coordination of STAs' associations with APs. While existing approaches suggest tuning of APs' beacon powers or using transmit power control (TPC) for association control, here, the signal-to-interference-plus-noise ratio (SINRs) of STAs and the clear channel assessment (CCA) threshold of the 802.11 MAC protocol are employed. The proposed algorithms in this thesis enhance throughput and minimize coverage holes inherent in cell breathing and TPC techniques by not altering the transmit powers of APs, which determine cell coverage. Besides uncoordinated AP associations, unnecessary frequent transmission deferment is envisaged as another problem in DWLANs due to the clear channel assessment aspect of the carrier sensing multiple access collision avoidance (CSMA/CA) scheme in 802.11 standards and the short spatial reuse distance between co-channel APs. To address this problem in addition to AP association coordination, an algorithm is proposed for CCA threshold adjustment in each AP cell, such that CCA threshold used in one cell mitigates transmission deferment in neighboring cells. Performance evaluation reveals that the proposed association optimization algorithms achieve significant gain in throughput when compared with the default strongest signal first (SSF) association scheme in the current 802.11 standard. Also, further gain in throughput is observed when the CCA threshold adjustment is combined with the optimized association. Results show that when STA-AP association is optimized and CCA threshold is adjusted in each cell, throughput improves. Finally, transmission delay and the number of packet re-transmissions due to collision and contention significantly decrease.