Scielo RSS <![CDATA[SAIEE Africa Research Journal]]> vol. 113 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Using blinds, day-lighting, and geyser temperature settings to reduce electricity consumption and pricing patterns in energy-efficient buildings</b>]]> Depending on the building architecture, usage, and energy consumption patterns, over US$ 60 billion was expended annually on electric lighting in commercial buildings. Therefore, the paper focuses on the development of energy-efficient buildings that minimize energy consumption through integrated energy-efficient design processes. This can serve as a practical guide to design buildings that can lower the energy requirements and a strategy to reduce energy consumption. In this study, predictive analytics were used to examine how blinds, daylighting, and geyser temperature settings can reduce electricity consumption and pricing patterns. A panel of expert judges was used to validate the 5-point Likert scale residential electricity load management questionnaire used to gather survey data for the statistical analysis in a Windhoek suburb, Namibia. The main goal of this study was to investigate how blinds, day-lighting, and geyser temperature settings can be used to save energy, reduce electricity consumption, and costs for sustainable growth and development. The results from this investigation indicate a perfect Gaussian histogram of 15 electricity price jumps confirming 15 four-way stepwise interaction effects. Optimal 0.5 Quetelet curve index offers average citizen energy efficiency awareness, education, and behavior modification for affordable electricity. Females generally set hotter geyser temperatures and are higher energy consumers. Blinds reduce electricity consumption by 50% in summer, 25% in winter, and day-lighting by 25%. These were the least cost and optimal solutions to the rising electricity consumption and pricing patterns problem. Adopting the findings or the outcomes of this paper could provide more optimal and sustainable energy consumption thereby reducing pressure on the power grid. <![CDATA[<b>Terrestrial Free Space Optical Communication Systems Availability based on Meteorological Visibility Data for South Africa</b>]]> In spite of the numerous advantages of employing free space optical (FSO) communication systems as viable complementary platforms for next-generation networks, the presence of atmospheric disturbances such as fog and scintillations are major sources of signal impairment which degrade system performance. Consequently, it becomes imperative to investigate and contextualize the unique climatic conditions in those locations where FSO links are to be deployed. Statistical evaluation of meteorological visibility data collected for various cities in South Africa is thus hereby employed in estimating the availability performance of FSO links transmitting at both 850 nm and 1550 nm. It is determined that the cities of Mbombela and Cape Town have the lowest performance due to the high occurrence of fog events as compared to other regions in South Africa. During foggy periods, FSO links in Mbombela and Cape Town would have availabilities of ~99.6% for link distances of 500 and 600 metres, respectively. The bit error rate (BER) estimations of intensity modulation and direct detection (IM/DD) FSO links in the presence of weak atmospheric turbulence were also investigated for the identified locations during foggy weather; with the cities of Mafikeng and Kimberley showing the lowest BER performances because of their high wind velocities, altitudes and refractive index values. In order to obtain a BER of 10-6, receive signal-to-noise ratio (SNR) values ranging from ~46 to ~51 dB are required for FSO links deployed for data transmission in the various cities investigated in this work. <![CDATA[<b>Software validation of optimal bidirectional composite conductor design with applications</b>]]> The ever-increasing electricity consumption patterns worldwide and the very many drivers of load growth have placed heavy burdens on new and existing power supply infrastructures, globally. The measurement of standards of living based on the quantity and quality of electricity consumed has further exacerbated power systems transmission network problems. Software validation of optimal bidirectional composite conductor designs, which carry very high currents at high temperatures, vertically and horizontally in tandem, attempt to provide solutions to the above problems. Composites comprising a conductor and insulating material strips in which the density approaches the minimum conducting area and satisfies Laplace's equation was considered. The variational problem was homogenized and polyconvexified using Lagrange multipliers and Green's identity, while the Hessian was used to relax the minimized characteristic function for convexification. The results indicate materials and costs optimization. Both the horizontal and vertical currents were equal, without hotspots or irregular power transfer problems in the composite conductor matrix. The vertical and horizontal gradients along the composite were equal and optimal, and their respective directions of highest change were uniform along their lines of equal energy. The conductor materials occupied about two-thirds area of composite. The high-temperature low-sag cable is light in weight, strong, and bendable. Its larger diameter reduces corona effects, which makes it useful for voltages beyond 300 kV and can minimize the incidence of power blackouts, globally. <![CDATA[<b>Personal Information Two-dimensional Code Encryption Technology in the Process of E-commerce Logistics Transportation</b>]]> The popularity of the Internet has given birth to e-commerce and promoted the development of logistics industry. Traditional logistics is frail in personal information confidentiality, and it is easy to leak privacy information in the process of logistics. This paper briefly introduced the channels of privacy information disclosure in the process of e-commerce logistics and the privacy information encryption system based on two-dimensional code. Then, the privacy protective effect of the system was tested on the laboratory server. The results showed that mobile terminals with different permissions only obtained some necessary logistics information within their respective permissions in the normal process; the mobile terminals distinguished two-dimensional codes that did not belong to express mails, and only meaningless error codes were obtained after the mobile terminal without permissions scanned the code in the abnormal process. In conclusion, the encryption technology of personal information based on two-dimensional code can effectively protect the privacy information in the process of logistics.