Browsing by Author "Ssemakula, John Bosco"

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    A geospatial platform for visualizing underground utilities in growing urban centers
    (Journal of Engineering, Management and Information Technology, 2025-06-01) Mirondo, Godfrey Kibalya; Ssemakula, John Bosco; Modi ,Bosco Wilson; Niwareeba, Roland
    Urban development in rapidly expanding cities, especially in developing countries, is often hindered by limited access to accurate and current information on underground infrastructure. This paper introduces a web-based dashboard developed to map and visualize subsurface utilities in Kampala, Uganda. To support the development of this system, a field survey was conducted to collect baseline data on existing underground assets, validate geospatial records, and assess on-the-ground conditions. Designed to address critical data gaps, the dashboard integrates this field-verified information with open-source web technologies and multilingual support, offering an interactive and accessible platform for planners, engineers, and city officials. By enabling non-intrusive identification and exploration of underground assets, the dashboard supports safer construction practices, reduces the risk of accidental utility damage, and improves coordination among stakeholders. Ultimately, this solution contributes to more efficient urban planning and lays the foundation for Kampala's transition toward sustainable smart city development.
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    Grouped discrete Hartley transform precoding for low-complexity PAPR reduction in ACO-OFDM visible light communication systems
    (Journal of Optical Communications, 2026-09-07) Niwareeba, Roland; Birabwa, Denise Joanitah; Ssemakula, John Bosco
    The high peak-to-average power ratio (PAPR) remains one of the major challenges affecting asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) systems used in visible light communication (VLC). Although transform precoding techniques such as discrete Hartley transform (DHT) precoding can effectively reduce PAPR, their computational complexity increases significantly as the number of subcarriers increases, limiting practical implementation in large-scale systems. In this paper, a grouped discrete Hartley transform (G-DHT) precoding scheme is proposed for low-complexity PAPR reduction in ACO-OFDM systems. The proposed technique partitions the input symbol vector into smaller groups and independently applies DHT precoding within each group before OFDM modulation. This significantly reduces computational complexity while preserving the PAPR reduction capability of conventional DHT precoding. Simulation results show that the proposed scheme achieves measurable PAPR reduction without noticeable bit error rate (BER) degradation. At a complementary cumulative distribution function (CCDF) of 10−3, the proposed G-DHT scheme with group size G = 128 achieves approximately 0.95 dB PAPR reduction relative to conventional ACO-OFDM while reducing computational complexity by about 50 % compared with full DHT precoding. The results indicate that grouped DHT precoding provides an effective trade-off between PAPR reduction performance and implementation complexity in optical OFDM systems.