Browsing by Author "Byamukama, Maximus"

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    Energy Storage Options for Environment Monitoring Wireless Sensor Networks in Rural Africa
    (Springer, 2012) Byamukama, Maximus; Akol, Roseline; Bakkabulindi, Geofrey; Pehrson, Björn; Olsson, Robert; Sansa-Otim, Julianne
    This paper explores various traditional and emerging battery technologies available for deployments of automated environment monitoring devices using Wireless Sensor Networks (WSNs) in Africa and the considerations designers must take into account when implementing these systems. Environment-monitoring applications of WSNs are focusing more on reducing power consumption and optimizing data transmission and less on the constraints that their applications and deployment environments put on the energy storage device. We describe the various properties of energy storage devices and, for each, we highlight the requirements to be met for environment monitoring applications, especially in remote areas in Africa. We evaluate the performance of some of these energy storage options against the requirements using three use cases. We indicate the technologies that have shown reliability for each use case. We show that emerging battery technologies, such as Lithium Ion Capacitors are well suited for long-life low power deployments while the options for high-power deployments depend on the constraints faced by the designers, such as the power consumption of the sensor network components sand environment temperature range of the deployment environment.
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    Network Densification Strategies for Automatic Weather Stations: Challenges and Opportunities for Uganda
    (IST-Africa, 2016) Nsabagwa, Mary; Byamukama, Maximus; Otim, Julianne Sansa; Okou, Richard
    Access to quality, accurate and timely weather information is important. In order to improve weather information quality and quantity, increasing the number of operational Automatic Weather Stations, also referred to in this document as densification should be prioritized. In this paper, we provide research findings of a survey conducted from November 2014 to January 2015 to ascertain the status of weather stations in Uganda. Weather station density was found to be sparse and yet many of the available weather stations were non-functional. Based on the distribution of available operational weather stations, we are proposing densification strategies including climatological zones, security and land policies. To achieve sustainability of the weather stations, we commend improving human resources aspects among other things
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    New Techniques for Sizing Solar Photovoltaic Panels for Environment Monitoring Sensor Nodes
    (Journal of Sensors, 2019) Byamukama, Maximus; Bakkabulindi, Geofrey; Akol, Roseline; Sansa-Otim, Julianne
    The development of perpetually powered sensor networks for environment monitoring to avoid periodic battery replacement and to ensure the network never goes offline due to power is one of the primary goals in sensor network design. In many environment-monitoring applications, the sensor network is internet-connected, making the energy budget high because data must be transmitted regularly to a server through an uplink device. Determining the optimal solar panel size that will deliver sufficient energy to the sensor network in a given period is therefore of primary importance. The traditional technique of sizing solar photovoltaic (PV) panels is based on balancing the solar panel power rating and expected hours of radiation in a given area with the load wattage and hours of use. However, factors like the azimuth and tilt angles of alignment, operating temperature, dust accumulation, intermittent sunshine and seasonal effects influencing the duration of maximum radiation in a day all reduce the expected power output and cause this technique to greatly underestimate the required solar panel size.Themajority of these factors are outside the scope of human control and must be therefore be budgeted for using an error factor. Determining of the magnitude of the error factor to use is crucial to prevent not only undersizing the panel, but also to prevent oversizing which will increase the cost of operationalizing the sensor network. But modeling error factors when there are many parameters to consider is not trivial. Equally importantly, the concept of microclimate may cause any two nodes of similar specifications to have very different power performance when located in the same climatological zone. There is then a need to change the solar panel sizing philosophy for these systems. This paper proposed the use of actual observed solar radiation and battery state of charge data in a realistic WSNbased automatic weather station in an outdoor uncontrolled environment.We then develop two mathematical models that can be used to determine the required minimum solar PV wattage that will ensure that the battery stays above a given threshold given the weather patterns of the area. The predicted and observed battery state of charge values have correlations of 0.844 and 0.935 and exhibit Root Mean Square Errors of 9.2% and 1.7% for the discrete calculus model and the transfer function estimation (TFE) model respectively. The results show that the models perform very well in state of charge prediction and subsequent determination of ideal solar panel rating for sensor networks used in environment monitoring applications.
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    Towards a robust and affordable Automatic Weather Station
    (Development Engineering, 2019) Nsabagwa, Mary; Byamukama, Maximus; Kondela, Emmanuel; Sansa Otima, Julianne
    The frequency and severity of extreme weather events have increased over the last 30 years, making predictability of weather a challenge. Weather extreme events often cause adverse impacts to lives and property. Thus, accurate and timely provision of weather data is becoming crucial to improve the skill of weather prediction and to strengthen resilience to the impacts of the adverse weather conditions. Uganda and many developing countries have challenges in acquiring accurate and timely weather data due to their sparse weather observation networks. The sparse weather observation networks are in part attributed to the high cost of acquiring an Automatic Weather Station (AWS) and limited funding to national meteorological services of the respective countries. The inability of developing countries to manufacture their own AWSs leads to high recurring costs accruing from importation and maintenance. In this study, we propose an AWS based on Wireless Sensor Networks. We plan to design three generations of the AWS prototype, the first being the subject of this paper. The purpose of this paper is therefore to evaluate the first-generation AWS prototype and to propose improvements for the second-generation, based on needs and requirements. Results from the AWS prototype data suggest improving non-functional requirements such as reliability, data accuracy, power consumption and data transmission in order to have an operational AWS. The non-functional requirements combined with cost reduction produces a robust and affordable AWS. Therefore, developing countries like Uganda will be able to acquire the AWSs in reasonable quantities, hence improvement in weather forecasts.