http://localhost/xmlui/handle/123456789/1156 2026-04-05T05:46:15Z 2026-04-05T05:46:15Z M’Nkanatha, Geoffrey Gichuru Nduati, Eunice Boitt, Mark Mwaniki, Mercy http://localhost/xmlui/handle/123456789/6891 2026-02-16T10:33:05Z 2026-02-16T00:00:00Z

Estimating Heights of Buildings for Construction and Monitoring Changes Using Drone Imagery M’Nkanatha, Geoffrey Gichuru; Nduati, Eunice; Boitt, Mark; Mwaniki, Mercy In today’s world, many applications require geolocated building information with accurate heights. Building heights can be used for various purposes, including estimating the number of floors, inspecting buildings that violate approved plans, assessing rental income, determining the number of people living in a place, and evaluating energy consumption. Obtaining accurate and reliable building heights has been a challenge. This study aimed to demonstrate how building heights can be estimated accurately using drone imagery. The methodology was tested in Juja sub-county, Kiambu County, Kenya. Drone image data was used to generate Digital Terrain Model (DTM), Digital Surface Model (DSM), and normalized Digital Surface Model (nDSM) products, which aided in estimating building heights and floor numbers. The heights of buildings from drone data and ground survey methods were compared, yielding a correlation of 0.99. Similarly, a comparison between the number of floors from drone data and field observations showed a correlation of 0.92. Validation was also performed for the 2D aspects by comparing the quality of the digitized orthophoto with the vectorized and regularized buildings extracted from the orthophoto through unsupervised classification. The intersection matching was 82%, which falls within the acceptable range for accuracy assessment. These results proved that drone data can sufficiently provide accurate building heights, saving human resources, money and time. Thus, applications requiring regular monitoring of building heights, especially during construction stages to determine compliance with building regulations may consider the 3D reconstruction of overlapping aerial drone images. Keywords:Drone Image Data, Digital Terrain Model (DTM), Digital Surface Model(DSM), Normalized Digital Surface Model (nDSM), Building Heights and Floor Numbers Journal of Building Construction and Planning Research

2026-02-16T00:00:00Z Wanjala, Bramwel W. http://localhost/xmlui/handle/123456789/6770 2025-07-17T07:30:50Z 2025-07-17T00:00:00Z

Storage RootYield ofSweetpotato asInfluenced bySweetpotatoleaf curl virus and Its Interaction With Sweetpotato feathery mottle virus and Sweetpotato chlorotic stunt virus in Kenya Wanjala, Bramwel W. (SPLCV) and its interactions with Sweetpotato feathery mottle virus (SPFMV) and Sweetpotato chlorotic stunt virus (SPCSV) on root yield was determined. Trials were performed during two seasons using varie ties Kakamega and Ejumula and contrasting in their resistance to sweet potato virus disease in a randomized complete block design with 16 treatments replicated three times. The treatments included plants graft in oculated with SPLCV,SPFMV,andSPCSValoneandinpossibledualor triple combinations. Yield and yield-related parameters were evaluated at harvest. The results showed marked differences in the effect of SPLCV infection on the two varieties. Ejumula, which is highly susceptible to SPFMV and SPCSV, suffered no significant yield loss from SPLCV infection, whereas Kakamega, which is moderately resistant to SPFMV and SPCSV,suffered an average of 47% yield loss from SPLCV, despite only mild symptoms occurring in both varieties. These results highlight the variability in yield response to SPLCV between sweetpotato cultivars as well as a lack of correlation of SPLCV-related symptoms with yield reduction. In addition, they underline the lack of correlation between re sistance to the RNA viruses SPCSV and SPFMV and the DNA virus SPLCV. Keywords: Africa, begomovirus, crinivirus, cultivar/resistance, disease management, potyvirus, SPFMV, SPLCV, SPCSV, sweepovirus, treatment, yield PhD Research Publication

2025-07-17T00:00:00Z Wanjala, Bramwel W. http://localhost/xmlui/handle/123456789/6769 2025-07-17T07:12:51Z 2025-07-17T00:00:00Z

Loop-mediated isothermal amplification assay: A novel disease diagnostics tool in sweetpotato seed quality assurance Wanjala, Bramwel W. Sweetpotato is an important food crop in global production. However, sweetoptato viruses pose a threat to sustainable agriculture and cause significant economic loss. More than 30 viruses have been reported to date, with sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV) occurring frequently and in combination, causing sweetpotato virus disease. The detection of viruses directly from sweetpotato is still a challenge, and efforts are being made toward this front. Therefore, rapid detection of viruses is critical for effective control. Current diagnostic tests are not sufficiently sensitive to reliably detect viruses directly from sweetpotato and require expensive laboratory equipment and a high level of skilled experience. Loop-mediated isothermal amplification (LAMP) is sensitive and spe cific for both DNA/RNA amplification; it is affordable and its characteristics make it potentially suitable for on-site testing. LAMP assays have been developed for sev eral sweetpotato viruses: SPCSV, SPFMV, and sweet potato leaf curl virus (and related sweepoviruses). Laboratory validation showed a 100% diagnostic sensitiv ity for all three viruses. The LAMP on-site testing results were comparable to those of polymerase chain reaction and reverse transcriptase polymerase chain reaction confirmatory laboratory tests. Interlab validation and packaging into affordable kits will ensure high adoption in sub-Saharan Africa. The LAMP assay can be used for field surveys and monitoring the phytosanitary status of pre-basic seed production in quarantine or certification program. This guarantees pathogen-free planting material enters the seed system. We discuss opportunities for LAMP as a diagnostic assay for the rapid detection of sweetpotato viruses and its adoption as a quality control system for planting materials PhD Research Publication

2025-07-17T00:00:00Z Wanjala, Bramwel W. http://localhost/xmlui/handle/123456789/6768 2025-07-17T07:04:56Z 2025-07-17T00:00:00Z

Loop-Mediated Isothermal Amplification assays for on-site detection of the main sweetpotato infecting viruses Wanjala, Bramwel W. Globally, Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV) occur frequently and in combination cause sweetpotato virus disease (SPVD). Many viral diseases are economically important and negatively impact the production and movement of germplasm across regions. Rapid detection of viruses is critical for effective control. Detection and quantification of viruses directly from sweetpotato remains a challenge. Current diagnostic tests are not sensitive enough to reliably detect viruses directly from the plant or require expensive laboratory equipment and expertise to perform. We developed a simple and rapid loop- mediated isothermal amplification (LAMP) assay for the detection of SPFMV, SPCSV and begomoviruses related to sweet potato leaf curl virus (SPLCV). Laboratory validation recorded 100 % diagnostic sensitivity for all the three viruses. The LAMP assays were customized for field testing using a lyophilized thermostable isothermal master mix in a ready-to-use form that required no cold chain. The average time to positivity (TTP) was: SPFMV 5 30 min, SPCSV 15–43 min s and begomoviruses 28 45 mins. LAMP on-site testing results were comparable to PCR and RT-PCR confirmatory laboratory tests. The LAMP assay is a powerful tool for rapid sweetpotato virus detection at a reasonable cost and thus could serve as quality control systems for planting materials. PhD Research Publication

2025-07-17T00:00:00Z