Electric Motor & Power Source Selection for Small Aircraft Propulsion

The research conducted in this project is on electrical propulsion in aviation. A Cessna 172K aircraft with a Lycoming O-320-E2D piston engine serves as a baseline measurement. Investigation of the components required for electrical flight is performed, and components are selected based on market availability and operational performance criteria. This research focuses on electrical propulsion in the aviation industry, and is tailored to aircraft within the General Aviation sector leading to the following research question: Can current electric motor and battery technologies conceptually support flight operations for a Cessna 172K in terms of aircraft performance criteria? The results explore the potential for a fully-electric aircraft powered by means of batteries. A demonstrated flight is examined and the center of gravity is calculated

Characterisation of Mobile Data Usage in Township Communities

The paper describes a measurement study of mobile Internet usage in township communities in South Africa. The idea is to understand usage pattern of mobile data that would motivate the provisioning of a localised cloudlet infrastructure with an appropriate set of services

A Comparison of Nutritional Habits, Physical Function and Psychological Constructs between Urban and Rural Costa Rican Older Adults

Purpose: To compare nutritional habits, physical function and psychological constructs between Costa Rican older adults from urban and rural zones.Methods: Male and female older adults aged ? 65 yr. from urban (n = 185) and rural (n = 109) Costa Rica were assessed on nutritional habits, physical function measures, and cognitive function by a face-to-face interview.Results: Rural older adults consumed more daily carbohydrates, protein, and energy at breakfast and lunch (p < 0.05 for all), and more carbohydrates (p ? 0.001), fat (p = 0.002), protein (p ? 0.001), and energy (p ? 0.001) at dinner than urban elderly. Aerobic power (p = 0.044) was higher in urban compared to rural elderly. A correlation was found between aerobic power and global fatigue (r = -0.20, p = 0.014) in urban elderly. Lifetime cognitive activity correlated to total energy (r = 0.37, p = 0.003), carbohydrate (r = 0.37, p = 0.002), and protein (r = 0.34, p = 0.005) consumption in rural elderly. Higher depression scores (p = 0.048), and lower lifetime cognitive activity were observed in urban compared to rural elderly (p = 0.004).Conclusion: The health profile is positive for either group depending on the variable analyzed, except for a higher aerobic power, which provides benefits to the entire cohort

TownshipNet: A Localized Hybrid TVWS-WiFi and Cloud Services Network

This paper describes a network architecture to provide low cost last mile access and cloud services for local content sharing in a poorly resourced township environment. We describe how ICT solutions are developed in close partnership with the local community who will benefit from the interventions. We analyze the data usage patterns of mobile users in the township to provide us with a real understanding of the needs of the community. This data usage analysis is used to inform the design of the network and of the localized cloudlet services. The network consists of hybrid TV White Space and WiFi backhaul and WiFi public access points

Collaborative Neighbour Monitoring in TV White Space Network

Collaborative sensing among secondary users in television white space (cognitive radio) networks can considerably increasethe probability of detecting primary or secondary users. In current collaborative sensing schemes, all collaborative secondary users are assumed to be honest; however, the deployment of such networks is susceptible to attacks by malicious users, in which malicious secondary users either report false detection results or inject falsified data in order to unduly occupy a specific channel and deny other nodes from using it. This work seeks to allow each secondary user to monitor its neighbour to ensure there is no spectrum abuse by any secondary users so as to improve spectrum fairness in dynamic spectrum access (DSA) networks

Work In Progress:A Channel Selection Algorithm for a TVWS Mesh Network

The concept behind this work is to build mesh networks in the TVWS band for developing regions to improve internet access opportunities. The purpose is to solve a pertinent problem within the context, namely to find an optimal or almost optimal channel selection for the mesh. Both simulation as well as a trial network will be used to analyse performance

Comparison of thermal tolerance and standard metabolic rate of two Great Lakes invasive fish species

Round goby (Neogobius melanostomus) and western tubenose goby (Proterorhinus semilunaris) invaded the Laurentian Great Lakes at approximately the same time and area yet have shown substantial differences in their post-invasion success with more rapid establishment and development of much larger abundances of round goby populations throughout the invaded habitat. In this study, we compared differences in physiological performance (thermal tolerance and standard metabolic rate) between round and tubenose goby collected from the Huron-Erie corridor. Tubenose goby were observed to have lower thermal tolerance but exhibited similar standard metabolic rate across environmental temperatures compared to round goby. At temperatures exceeding 31oC, tubenose goby demonstrated significantly higher mortalities and shorter times to death relative to round goby. The observed differences in thermal tolerance were consistent with differences in the native geographic ranges observed for each species at their southern ranges. The observed differences in physiological performance combined with species differences in other life history traits such body size, reproduction, feeding ecology and habitat affiliation may also explain differences in the invasiveness experienced by these two Great Lakes invasive fish including a greater ability of round gobies to occupy extreme habitats with large water temperature fluctuations

A Correlation between RSSI and Height in UHF Band and Comparison of Geolocation Spectrum Database View of TVWS with Ground Truth.

An investigation into the Received Signal Strength Indica- tor (RSSI) dependency on receiver antenna height in UHF band is con- ducted. The results show a high correlation between RSSI and height on channels with high signal strength. There is approximately 2.5 dBm RSSI gain per 1 m increase in height above ground up to 8.5 m. From 8.5 m to 12 m, there is no consistent observable increase in RSSI. Further- more, the geolocation spectrum databases (GLSD) view of white space in the television band is compared with the ground truth. Results show signal presence on some of the channels indicated free by the spectrum database. These findings imply that an increase in transmission range of UHF links can be achieved by increasing receiver height. White space devices using A GLSD should additionally require spectrum scanning to determine clear channels

Performance analysis of a collaborative DSA-based network with malicious nodes

This work analyses the performance of a Dynamic Spectrum Access (DSA) network with secondary nodes to provide Internet services, and studies the impact of malicious nodes and cooperative secondary nodes on the performance of the network and spectrum utilization. The work mathematically models the throughput, latency, and spectrum utilization with varying numbers of malicious nodes, secondary nodes, miss probabilities, and false alarm probabilities, and studies their effect on the performance of the network. The results point to rapid spectrum starvation as the number of malicious nodes increase, as well as the negative impact of too many secondary nodes crowding out available spectrum with resultant degradation of throughput and latenc

The Shortcomings of Globalised Internet Technology in Southern Africa

Network protocols and applications have mostly been devel- oped in and for a Western context and usually have an embedded set of assumptions about network performance and availability. As a result web-browsing, cloud-based services, live voice and video over IP, desktop applications and software updates often fail or perform poorly in (rural) areas of Southern Africa. This paper uncovers some of the reasons for this poor performance such as Windows TCP failing to reach capacity in high-delay networks, long DNS delays or time-outs and applications such as Office365 assuming constant connectivity to function, and de- scribes them, set in the Southern African contexts. We address the issue of colonisation in ICT context and show the extend of such in the area of networking. These observations provide strong motivation for Africa- based engineering research to ensure that future network protocols and applications are context-sensitive, adaptive and truly global