Illumination Levels Research Articles

Neuromorphic Imaging With Joint Image Deblurring and Event Denoising.

Neuromorphic imaging reacts to per-pixel brightness changes of a dynamic scene with high temporal precision and responds with asynchronous streaming events as a result. It also often supports a simultaneous output of an intensity image. Nevertheless, the raw events typically involve a large amount of noise due to the high sensitivity of the sensor, while capturing fast-moving objects at low frame rates results in blurry images. These deficiencies significantly degrade human observation and machine processing. Fortunately, the two information sources are inherently complementary - events with microsecond-level temporal resolution, which are triggered by the edges of objects recorded in a latent sharp image, can supply rich motion details missing from the blurry one. In this work, we bring the two types of data together and introduce a simple yet effective unifying algorithm to jointly reconstruct blur-free images and noise-robust events in an iterative coarse-to-fine fashion. Specifically, an event-regularized prior offers precise high-frequency structures and dynamic features for blind deblurring, while image gradients serve as a kind of faithful supervision in regulating neuromorphic noise removal. Comprehensively evaluated on real and synthetic samples, such a synergy delivers superior reconstruction quality for both images with severe motion blur and raw event streams with a storm of noise, and also exhibits greater robustness to challenging realistic scenarios such as varying levels of illumination, contrast and motion magnitude. Meanwhile, it can be driven by much fewer events and holds a competitive edge at computational time overhead, rendering itself preferable as available computing resources are limited. Our solution gives impetus to the improvement of both sensing data and paves the way for highly accurate neuromorphic reasoning and analysis.

Optimizing Solar Energy Harvesting: An Arduino-Enhanced Dual-Axis Tracking System

Technological progress is enhancing the accessibility and potential of solar energy as a renewable source. This paper introduces a strategy leveraging Ohm's law and the power equation to derive additional energy from solar photovoltaic (PV) panels. The proposed method involves the integration of an automated solar tracking system employing both dualaxis and polar single-axis configurations. This system is comprised of a stationary vertical axis and a flexible horizontal axis, both under motor control. To enhance power output and efficiency, the trackers autonomously follow the sun, constantly adjusting the solar panel positions. The tracking system self-adjusts in the event of a 2 to 3-degree misalignment to minimize power loss due to continuous motor operation. Light intensity sensors analyze illumination levels on each side, guiding the panels toward the light source. The tracking motion continues until equal light exposure on both sides is detected, leading to an enhanced solar irradiance for the panels

Automated dynamic lighting control system to reduce energy consumption in daylight

Buildings, which are responsible for the majority of electricity consumption in cities like Dubai, are often exclusively reliant on electrical lighting even in the presence of daylight to meet the illumination requirements of the building. This inefficient use of lighting creates potential to further optimize the energy efficiency of buildings by complementing natural light with electrical lighting. Prior research has mostly used ballasts (variable resistors) to regulate the brightness of bulbs. There has been limited research pertaining to the use of pulse width modulation (PWM) and the use of ‘triodes for alternating current’ (TRIACs). PWM and TRIACs rapidly stop and restart the flow of current to the bulb thus saving energy whilst maintaining a constant illumination level of a space. We conducted experiments to investigate the feasibility of using TRIACs and PWM in regulating the brightness of bulbs. We also established the relationship between power and brightness within the experimental setups. Our results indicate that lighting systems can be regulated through these alternate methods and that there is potential to save up to 16% of energy used without affecting the overall lighting of a given space. Since most energy used in buildings is still produced through fossil fuels, energy savings from lighting systems could contribute towards a lower carbon footprint. Our study provides an innovative solution to conserve light energy in buildings during daytime.

PENILAIAN FAKTOR CAHAYA SIANG DI BILIK KULIAH POLITEKNIK KUCHING SARAWAK

The simplest form of description for the distribution, penetration and intensity of daylight is called the Daylight Factor (DF) which results from natural light (sunlight), the DF value is written as a percentage. This value is the ratio of the internal brightness at a point in a room to the natural external brightness on a horizontal surface. As a guide, the brightness inside the building and the associated distribution can be classified according to the natural daylight factor. The necessary natural daylight factors are lighting, glare and thermal comfort. Aspects of classroom lighting and decoration that can promote discomfort and affect task performance due to glare, and flicker (illumination waves above 100 Hz) that cannot be seen from fluorescent lighting. The focus of the study is to measure the level of natural daylight in the classroom. The main purpose of the study was due to students' complaints about the glare and discomfort of the lecture room. The equipment used is lux meter, anemometer and measuring meter. The results of the study show that the lecture room has a level of illumination that meets the standards, glare that cannot be seen and is acceptable for thermal comfort. The sky condition during the study was 100% cloudy with cloud cover. The average illuminance in the lecture room is 276.5lux in a cloudy sky situation (standard 5000-20000 lux) and the daylight factor (DF) of the day is 1.2 in the range of 1.00 to 3.5. The conclusion for this study shows that the daylight factor from natural light in the lecture room at the academic building of Politeknik Kuching Sarawak achieves acceptable standards for lighting, glare and thermal comfort, referring to the MS1525 and CIBSE A standards.

The Effect of Light Shelf and Translucent Ceiling on Daylighting Performance in Office Building in Thailand

Daylight control strategies were a challenge for a high-rise building in terms of savingenergy consumption. Light shelf was one of the daylight control systems which was usuallyhorizontal or inclined surfaces, placed on the inner and/or the outer side of windows toreflect sunlight to ceiling and distribute the light deeper into the room. This study aimedto investigate the performance of daylight control strategies in office rooms using alight-self with translucent ceiling. The light shelf, which is typically horizontal or inclined,was placed on the inner or outer side of windows to reflect sunlight and distribute itdeeper into the room. The study investigated the effect of type of daylight techniqueswhich are a combination of different light shelves and translucent ceiling on daylightingperformance. The illuminance level in an office room was calculated using DIALux 4.13 andwas performed for working hours in Bangkok, Thailand. The simulation was performedunder clear sky conditions and using real climatic data from four orientations. Fivetypes of daylight techniques, including the existing room, were investigated in terms ofilluminance level and uniformity of daylight in the office room. The CIBSE (2015) and IESNA(2011) standards indicate that offices room should have uniformity of at least 0.8 andan illuminance level of 500 lux. Thus, the objective of this research was to determine thebest combination of light shelves and translucent ceilings for achieving illuminance anduniformity standards. The results showed that the external light shelf with a translucentceiling and static louver at 90o (option 4) was the best solution for office rooms, providingaverage illuminance level 776 lux (above the standard) and uniformity 0.4 (nearly thestandard). This conclusion suggests that a light-shelf with a translucent ceiling guidesdaylight deep into the room but less uniformity.

Sensitivity analysis of sensor placement in energy-efficient, grid-interactive ready small office buildings with dynamic shading and lighting control

In smart buildings, dynamically controlled lighting and shading devices have a direct impact on occupants’ thermal and visual comfort, building energy use, and peak demand. This study aims to assess the impacts of adjusting vertical and work plane illuminance sensor location and rotation for different zone orientations across different climate zones, on illuminance levels, glare, energy consumption, and demand. Using the sensor locations of 1.6 m and facing the window (typical assumption), when implementing the integrated shading and lighting controls, the lighting and cooling energy savings range from 41% to 71% across both heating and cooling-dominated climate zones. The greatest cooling peak use demand reduction of 6.5 kW (23%) is achieved in Climate Zone 2 A, where the total cooling and lighting demand savings are 28-33% (9-10 kW). The percent change in lighting energy use is greater as compared to the percent change in cooling energy use when sensor location is varied, however, the total kWh and kW change is greater for cooling in most climate zones. Results suggest that adjusting the sensor distance from the window has a greater impact on illuminance levels, glare, and lighting and cooling energy use in all climate zones as compared to sensor rotation.

Analyzing the effect of shot noise in indirect Time-of-Flight cameras

Continuous wave indirect Time-of-Flight cameras obtain depth images by emitting a modulated continuous light wave and measuring the delay of the received signal. In this paper we generalize the estimation of the effect of the shot noise when obtaining the phase delay with an arbitrary number of points in the Discrete Fourier Transform, extending and generalizing the analysis done in previous works for the case of four points. For that particular case, we compare our analysis with the state of art. Moreover, we extend the error model using a second order approximation in the error propagation analysis, which provides more accurate estimations according to the Montecarlo simulation experiments. The analysis, based on both analytical and numerical methods, shows that the phase error is, in general, related to the exposure time and weakly to the number of points in the Discrete Fourier Transform. It also depends on the background illumination level, on the amplitude of the received signal, and, when using a three point DFT, on the distance to the objects.

Integration of Charge-Carrier Dynamics and Electrochemical Modeling in a Unified Microkinetic Model for the Oxygen Evolution Reaction in Water Splitting

Water-splitting in a photo-electrochemical cell is a promising method for the sustainable production of hydrogen. However, these cells are not yet able to achieve the efficiencies required for commercial use. The reaction that generates oxygen at the photo-anode, the oxygen evolution reaction (OER), is commonly regarded as the performance limiting reaction. Modeling of the OER can provide several opportunities [1,2]: (1) to identify and verify the prominent reaction mechanism by comparison to experimental electrochemical data, (2) to determine variables that are difficult to obtain from experiments, such as the surface coverage of the intermediate OER reaction species at the semiconductor-electrolyte interface, and (3) to rapidly explore new semiconductor materials for increased oxygen evolution.Previously in our group, a time-dependent non-linear microkinetic model of the OER has been developed. [3,4] This model consists of two parts: (1) A microkinetic model of the reaction kinetics at the semiconductor-electrolyte interface. The model equations describe the time-evolution of the current density and the intermediate species under applied potential. (2) A simplified description of the charge-carrier transport dynamics at the surface of an iron oxide (hematite) semiconductor. This model is able to simulate the steady-state behavior, such as current-voltage curves. However, the dynamic behavior and the simulation of electrochemical impedance spectra are not possible with the current model.Therefore, in this work a more detailed description of the charge-carrier dynamics is developed and implemented. While in the earlier model [3, 4] the two charge-carriers, electrons and holes, were simulated only at the surface of the semiconductor, in this work, also processes in the bulk of the semiconductor are included, through addition of a space-dependency of the charge-carriers in the semiconductor. The advantage is that we can fully include drift-diffusion effects, charge transfer at the interface, electron-hole pair generation, and the recombination processes at the interface and in the bulk of the semiconductor. The resulting partial differential equations are connected to the state-space system of the reaction kinetics through semi-discretization in the spatial dimension.In addition, we will present a global sensitivity analysis to characterize the influence of the model input parameters, such as free energies and reaction rates, on the output, i.e. current density. [5] This analysis, using Sobol's method, presents the influence of each parameter on the uncertainty of the model output, the current density, at different potentials. [6] As a result, this analysis can indicate exactly which parameters to research to decrease the output uncertainty most effectively.This work presents for the first time an integration of the spatial charge-carrier dynamics and the electrochemical model of the OER into one combined model. As such, we can investigate the limiting processes in both components simultaneously, while the sensitivity analysis allows us to probe these limiting processes under a wide range of conditions, such as varying illumination levels and temperatures. The combined model, in conjunction with global sensitivity analysis, will be used to accurately determine the surface coverages of the OER, which can be validated by comparison with experimental data, e.g., from ATR-FTIR measurements. [7] Additionally, by implementing different materials, in addition to iron oxide, we aim to identify the most promising catalyst for OER.[1] X.Q. Zhang, A. Bieberle-Hütter. ChemSusChem 2016 9, 1223-1242.[2] B. Samanta, Á. Morales-García, F. Illas, N. Goga, J.A. Anta, S. Calero, A. Bieberle-Hütter, F. Libisch, A.B. Muñoz-García, M. Pavone, M.C. Toroker. Chem. Soc. Rev. 2022 51, 3794-3818.[3] K. George, M. van Berkel, X. Zhang, R. Sinha, A. Bieberle-Hütter. J. Phys. Chem. C 2019 123 (15), 9981–9992.[4] K. George, T. Khachatrjan, M. van Berkel, V. Sinha, A. Bieberle-Hütter. ACS Catalysis 2020 10 (24), 14649–14660.[5] I.M. Sobol. Math. Model. Comput. Exp. 1993 1 (4), 407-414[6] B.F.H. van den Boorn, M. van Berkel, A. Bieberle-Hütter. Adv. Theory Simul. 2022, 2200615.[7] A. Bieberle-Hütter, A. Bronneberg, K. George, M.C.M. van de Sanden. J. Phys. D: Appl. Phys. 2020 54, 133001.Figure 1: Framework of the microkinetic model with two components: (1) the electrochemical model with the OER reaction mechanism, and (2) the charge-carrier dynamics with drift-diffusion, charge transfer and recombination processes. The results of the global sensitivity analysis of the electrochemical model are represented by the sensitivity indices (SOER), which express the influence of each of the input parameters on the output, i.e., the current density, as a percentage. Figure 1

Simulated Design and Evaluation of Centralized off Grid Street Light Solar Power System with Backup Generator

In this paper, simulated design and evaluation of centralized off grid street light solar power system with backup generator is presented. The design of the street light solar power system takes into consideration the desired illumination level, the width of road, the coefficient of utilization, the maintenance factor, the desired distance between street light poles, the pole height, the pole space to pole height ratio and the total length of the street. The case study street light is located along IBB Avenue in Uyo, with latitude and longitude of 5.016982, 7.911769 respectively, path length of 2.2 km and daily energy demand of 125.8 kWh/day. The PVSyst simulation results show that the solar fraction is 0.993 which indicates that 99.3 % of the energy demand of the street light is supplied from the solar power while the remaining 0.7% of the energy demand is supplied form the backup generator. The total energy supplied by the generator is 375.7 kWh whereas the total annual energy generated from the PV array is 53739 kWh. The annual total of the energy demand is 46059 kWh while the annual total of the energy supplied to the street light from the solar power system is 46027 kWh. Also, the annual mean of the battery state of charge (SoC) is 80.3 %. Also, it is noted that the month of August alone has about 375.7 kWh energy supply from the backup generator with about 98 liters of fuel. Specifically, in a whole year, the backup generator will be used for only three days in August, namely, on the 13th, 14th and 15th of August, with the maximum supply of 239.8012 kWh occurring on the 14th day of August. Furthermore, the performance ratio (PR) of the system is 48.5%. In all, the results show that the solar power system is able to supply the required energy demand of the case study street light with only 0.7% deficit which is supplied from the backup generator.

Effects of indoor lighting environments on paper reading efficiency and brain fatigue: an experimental study

Introduction: This study investigated the influence of indoor lighting environments on paper reading efficiency and brain fatigue to explore lighting parameters that benefit users during various reading durations.Methods: The study was conducted in the Smart Lighting Lab, where 12 participants were tested under different illuminance levels and correlated color temperatures (CCT) for three distinct reading durations. Reading efficiency during the task tests and objective measures of brain activity by monitoring participants’ electroencephalograms (EEGs) were used as key factors to assess participants’ fatigue levels.Results: By analyzing the subjective and objective results, we found that paper reading efficiency was significantly affected by changes in the lighting environment. Also, based on the results of this study, we propose lighting recommendations for paper reading tasks of different durations. For a 15 min reading task, the lighting condition of 500 lux-6,500 K were the most efficient for reading; for a 30 min reading task, 500 lux-4,000 K lighting environments were found to be the most effective; and 750 lux-6,500 K was the best lighting environment for a 60 min reading duration.Discussion: These suggestions can serve as a reference for designing indoor lighting environment. In addition, they provide guidance to researchers and reviewers conducting similar studies.

Daylight performance of collector-diffuser combinations in light pipe systems at different geographical locations

Incorporating daylight inside occupied spaces has several benefits, including reduced lighting load, improved mental and physical health of occupants, and increased productivity during working hours. Several Innovative daylighting systems that utilize advanced technologies and design approaches are devised and tested to bring natural light into occupied spaces. Amongst them, the Tubular Daylighting Devices (TDD) have immense potential to trap the sunlight and carry it to enclosed/dimly lit areas, especially in tropical climates.The careful selection of system components dictates TDD's spatial and temporal illumination performance. The present study aims to analyze and correlate the performance of various TDD systems with different collector-diffuser configurations widely reported in the literature and used commercially. The study uses the Daily Useful Daylight Illuminance (DUDI) paradigm and uniformity criterion to assess the performance of carefully chosen collectors, namely, hemispherical dome, prismatic dome, and faceted collector, with the selected diffusers: flat plate acrylic, hemispherical dome, flat prismatic, and flat Fresnel lens. The study encompasses the identification, modeling, and simulation of different configurations throughout the year at four chosen cities in India. Results indicate that the maximum and average lighting level measured is high in the case of the hemispherical collector when paired with flat diffusers at all seasons and cities considered for the study. A matrix of different configurations of system components is tabulated for each location based on a predefined criterion. The increase in diameter of the tube improved the lighting level above 150 lx even at a distance of 1.5 m from the center, and splitting the light pipe into two pipes of an equivalent cross-sectional area improved the end illumination levels at the periphery of the room (10–25 %) making it better in terms of both illuminance and uniformity when paired with hemispherical/faceted collector and flat diffuser.

Scalable Photochromic Film for Solar Heat and Daylight Management.

The adaptive control of sunlight through photochromic smart windows could have a huge impact on the energy efficiency and daylight comfort in buildings. However, the fabrication of inorganic nanoparticle and polymer composite photochromic films with a high contrast ratio and high transparency/low haze remains a challenge. Here, a solution method is presented for the in situ growth of copper-doped tungsten trioxide nanoparticles in polymethyl methacrylate, which allows a low-cost preparation of photochromic films with a high luminoustransparency (luminous transmittance Tlum = 91%) and scalability (30 × 350 cm2 ). High modulation of visible light (ΔTlum = 73%) and solar heat (modulation of solar transmittance ΔTsol = 73%, modulation of solar heat gain coefficient ΔSHGC = 0.5) of the film improves the indoor daylight comfort and energy efficiency. Simulation results show that low-e windows with the photochromic film applied can greatly enhance the energy efficiency and daylight comfort. This photochromic film presents an attractive strategy for achieving more energy-efficient buildings and carbon neutrality to combat global climate change.

Indoor Environmental Quality Assessment of Train Cabins and Passenger Waiting Areas: A Case Study of Nigeria

The adequacy of the indoor environmental quality (IEQ) in mass transit microenvironments is crucial to the well-being of exposed commuters. By 2050, many developing tropical countries will host even more megacities, which will feature an increase in people mobility and higher occupancy density. The paucity of IEQ studies, the technology gap, and inadequate policy measures to assure safer and sustainable mobility in many developing tropics have reinforced the current study objective. Also, the recent COVID-19 pandemic has highlighted the IEQ links and risks to health in transport, which, given the climate peculiarities, transport reforms, and huge commuter traffic in Nigeria, inform the study motivation. The indoor air quality (CO2, PM, VOCs, NO2), thermal, acoustic, and visual environments were objectively assessed in train passenger cabins and waiting areas, during 15 trips in the dry and rainy seasons in Nigeria. The results were analyzed by following the IEQ requirements defined in the ISO, CEN, ASHRAE, and SAE standards. The results indicate gaps in the IAQ (inadequate ventilation in 9 trains), defective thermal comfort (9 trains), exceedance in the PM limit (PM10: 47.9–115 μg/m3, PM2.5: 22.5–51.3 μg/m3), noise (Leq range: 64–85 dBA), and low illuminance levels (10 trains), hence the need for IEQ, interventions, stakeholder awareness, and broader IEQ studies on transport cabins in these regions.

Small tube-nosed seabirds fledge on the full moon and throughout the lunar cycle.

Many seabirds are attracted to anthropogenic light, and the risk is greater for recent fledglings. Moon phase predicts the probability of stranding (fewer birds strand on the full moon), but it remains uncertain whether moon phase is associated with when young seabirds fledge. Fledging behaviour of nocturnal, burrowing seabirds can be difficult to monitor using traditional methods but can provide insight into environmental factors that influence the risk of stranding. We used passive integrated transponder tags to monitor the fledging dates and times of Leach's storm-petrel (Hydrobates leucorhous) chicks across four breeding seasons (2017, 2018, 2021, 2022) at a major colony in Newfoundland and Labrador, Canada. We also assessed whether moon phase and incident illumination related to fledging date and time. The median fledge time was 1.6 h after sunset (0.6-11.7 h). The median fledge date was 10 October, and fledging dates ranged from 13 September to 13 November. Most importantly, moon phase was not associated with the time and date that Leach's storm-petrel chicks fledged. These results suggest that recently fledged storm-petrels are less attracted to anthropogenic light during high levels of natural illumination, which could indicate periods of higher stranding risk and help concentrate conservation efforts.

ОРГАНИЗАЦИЯ СИСТЕМЫ УПРАВЛЕНИЯ ОФИСНЫМ ОСВЕЩЕНИЕМ С ВОЗМОЖНОСТЬЮ ТОЧЕЧНОЙ НАСТРОЙКИ

This article describes a specific approach to organizing the artificial light environment of an office space with a common space. The main criteria of modern lighting systems are given, which must be taken into account when designing. It is proposed to create an energy-efficient system with great functionality to integrate a lighting control module into the existing system, which includes LED lamps with built-in microcontrollers. To control the level of illumination and the color spectrum emitted by the LED lighting device in real time, it is proposed to use a portable small-sized sensor. The system for monitoring and controlling lighting parameters is built using Wi-Fi wireless data transmission technology. The control system will make it possible to carry out point individual adjustment, taking into account the specified operating parameters and user requirements.

Rethinking Indonesia’s lighting standard for urban kampung roads

The latest lighting standard in Indonesia, SNI 7391:2008, emphasizes uniform distribution for road lighting to ensure the safety and accuracy of motorists. However, in urban kampungs, local roads serve as non-commercial public spaces and require lighting that is suitable for human-scale activities. This study examines road lighting in Siwalankerto, Surabaya, and explores how residents' nighttime experiences relate to their perceived adequacy of illumination (PAI). The research involved 26 participants who rated their experiences while using the local road after dark. Nighttime experiences, including pleasantness, willingness to stay, and safety, were compared to illuminance levels and PAI. The findings show a correlation between perceived adequacy of illumination and pleasantness, as well as the willingness to stay in the road space. There was no significant correlation between safety and PAI.

Field measurements of post-operation evaluation of daylighting and thermal comfort in hot and arid climates: A pilot study of three educational buildings on the Najran University campus in Saudi Arabia

The average energy consumption of educational buildings is constantly increasing due to their reliance on information technology equipment, expanded occupancy to accommodate new academic programs, and increased use of lighting and cooling systems. This research aims to gather data on the performance of lighting and cooling systems, as they are the two largest energy consumption systems on Najran University campus. It also explores opportunities to optimize the energy efficiency of the buildings, and it attempts to determine the satisfaction of Najran University users with the two operation systems (i.e., lighting and cooling). The research methodology depended on on-site measurements and online surveys. The on-site day lighting measurements confirmed that the maximum daylight illuminance levels were less than 100 lux in most workplaces and exceeded 100 lux only in a few workplaces, which were adjacent to windows. In addition, the field measurements of indoor temperature are 14.3–25.33 °C, which is a little cooler than the thermal comfort range during the majority of the year. Furthermore, the results of the building user questionnaire revealed that 73.1 % of respondents expressed satisfaction with the natural light levels at their workplaces. Only 57.7 % of respondents confirmed their satisfaction with the workplace temperature. However, the energy-efficient use of air-conditioning and artificial lighting systems would require the systems to be more flexible and dynamic. This research recommends optimizing control systems of air conditioning and artificial lighting systems to be converted to intelligent operation systems. That change would facilitate achieving energy-efficient buildings and give individual users adjustment options to adjust the comfort settings in their workplaces.

Camera calibration method through multivariate quadratic regression for depth estimation on a stereo vision system

Machine vision systems have demonstrated practical applications in various fields where the perception of the environment is essential. Stereo vision systems are one of the most used methods to perform three-dimensional mapping. These systems have several considerations in order to fulfill this task; One of them is camera calibration. This is why this paper proposes a novel camera calibration method for improving depth estimation accuracy in stereo vision systems. The method addresses the lens distortion issue by adjusting the surface point's pixel coordinates before the triangulation process. The new pixel coordinates are computed using calibration coefficients, which are calculated through multivariate quadratic regression. Also, the proposed method corrects the relative orientation of the cameras and computes a compensation angle. The proposed method is remarkably robust to varying illumination levels because it adjusts pixel positions independently of image content. In comparison to traditional methods, this method requires fewer steps to implement, as it only requires one image per camera. The proposed method could have significant implications for fields such as autonomous navigation and robotics, where depth estimation is a crucial component. Overall, this paper presents a valuable contribution to the field of computer vision by offering a new, efficient and effective approach to camera calibration for stereo vision systems. The performed experiments demonstrated that the proposed method leads to improved depth estimation in the stereo vision system with an improvement of 34.15% on the MAE and 48.38% on the STD when compared to one of the most commonly used methods.

Design and Fabrication of Greenhouse Monitoring and Control System Based on Global System for Mobile Communication and Bluetooth

Greenhouse technology should be embraced as a way of minimizing food insecurity in Kenya. Greenhouses have attempted to solve this problem by enclosing crops in a climatically controlled environment. In the past, greenhouses utilized electromechanical devices such as thermostats to monitor and control the greenhouse environment. Mechanical systems lack the flexibility and precision required for greenhouse control. Some modern greenhouses use computers -based controllers, which are station- based, bulky and costly. In this study a wireless prototype greenhouse monitoring and control system that is flexible, cheap, easy to maintain and easy to assemble was developed and implemented. The hardware consisted of ATmega328 microcontroller, Global System for Mobile communication (GSM) SIM800L module, HC05 Bluetooth module, HD44780U Liquid Crystal Display (LCD) module, 5 volts 4 channel relay module, Light dependent resistor (LDR) sensor and digital humidity and temperature (DHT11) sensor. The DHT11 and LDR sensors, the relay, the LCD, the GSM and the Bluetooth modules were interfaced to the ATmega328 microcontroller, through Arduino software, a program was written in C language, developed and uploaded to the ATmega328 microcontroller to run the greenhouse prototype. The designed prototype system is able to measure temperature, humidity, and light illuminance levels in the prototype greenhouse and display the values on the LCD. The system also transmits the measured values to owner’s phone via Bluetooth or GSM and keeps these parameters at optimum levels by use of two fans, a heater, a bulb and a sprinkler. From results, when the actuators were on, the average internal temperature was 24.5 ºC while the average external temperature was 31.43 ºC. The average temperature control effect and cooling efficiency per hour for the designed prototype were 6.9 ºC and 75.9%, respectively. At stable cooling state, the maximum cooling efficiency was 78%. This project therefore provides a cost effective and efficient means of monitoring and controlling greenhouse parameters. In addition, the system allows mobility during monitoring and control process. The agricultural sector in Kenya, can apply the designed prototype in the design and implementation of greenhouses.

Daylighting Simulation for Sustainable Certified Building - Tokyo Global Square, Minato City, Japan

According to the World Green Building Council, Sustainable Building or Green building refers to a building that, in its design, construction, or operation, minimises or eliminates negative impacts on the climate and natural environment while also creating positive impacts and improving our quality of life. It aims to conserve natural resources. This study focuses on assessing the effectiveness of daylighting in enhancing the overall efficiency of an office building. The selected office building, Tokyo Toranomon Global Square, located in Minato City, Tokyo, Japan, is certified by LEED and has received sustainable ratings. LightStanza has been utilised as a daylighting simulation tool for this study. The findings reveal that several factors influence the efficiency of the space, including building orientation, window type, glass type, facade materials, and room depth. Through computer simulations, it has been determined that the average illuminance level of daylight entering the building meets the ideal illuminance values specified by specific organisations that provide criteria for optimal lighting in office working spaces, namely as the Japanese Industrial Standard, (JIS Z 9110, 2010 – General rules of recommended Lighting Levels).