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The increase in the population of senior citizens created a new challenge of the shortage of healthcare workers to take care of the elderly. The elderly with multiple chronic conditions face problems in managing their daily medication intake. This has inspired us to design a low-cost Smart Internet of Things (IoT) Mobile Medication Dispenser (SMMD) to take care of the daily medication intake of the elderly. SMMD consists of hardware (medication dispenser) and software (an app for the user to control the SMMD and program the time to dispense the medication). The NodeMCU is used to control the stepper motor, organic light-emitting diode (OLED), and motor driver. The OLED displays the current time and the time set by the caregiver/elderly to take the medicine. The SMMD with three wheels enables it to move and dispense medication to the elderly. The NodeMCU is connected to the Firebase database to access the time required to dispense the medicine. The total cost of SMMD is USD50 and is affordable for the elderly from the lower-income group and making the process of taking medicine not a hassle for the elderly. The price of SMMD can be much lower when it is mass-produced.

Solar energy is considered as a prominent source of renewable energy, mainly due to the vast abundance of sunlight and rapid advancements of photovoltaic (PV) technology. The performance, reliability and lifespan of PV systems are severely affected by numerous environmental factors and fault occurrences, which include: (1) extreme swing in the operating temperature; (2) low solar irradiation levels which appear undetected in PV systems, resulting in energy losses and degradation of PV panels; and (3) non-homogenous shading and accumulation of dirt on PV panels, causing thermal imbalance and hotspots on the panels. Therefore, it is important to monitor the operating temperature and homogeneous detection of sunlight on the PV modules to guarantee efficient energy production. In this paper, we present the development and demonstration of a sensor-assisted Internet of Things (IoT)-based photovoltaic-battery renewable energy system. The adoption of the IoT solution for monitoring the real-time variations in environmental factors and system performance is discussed here. For the PV-battery hardware module, solar panels along with rechargeable batteries are constructed to supply the system. Inverters and controllers are used to synchronize the voltage level and transformation of AC power from DC power. In the design of the IoT system, the Arduino Mega microcontroller and ESP32 TTGO board are used along with sensors for recording the temperature, presence of dust/dirt, and voltage and current levels. The working prototype enables real-time data to be captured and sent to the cloud database for data collection, performance analysis, and diagnosis/detection of faults in the proposed system.

Memory modules are widely used in varies kind of electronics system design. The capacity of the memory modules has increased rapidly since the past few years in order to satisfy the high demand from the end-users. The memory modules’ manufacturers demand more units of automatic test equipment (ATE)to increase the production rate. However, the existing ATE used in the industry to carry out the memory testing is too costly(at least a million dollars per ATE tester). The low-cost memory testers are urgently needed to increase the production rate of the memory module. This has in spired us to design a low-cost memory tester. A low-cost memory fault detection tester with all the major fault detection algorithms that used in industry is modelled using Very High Speed Integrated Circuit Hardware Description Language (VHDL) in this paper to support the need of the low-cost ATE memory tester. The fault detection algorithms modelled are MATS+ (Modified Algorithm Test Sequence), MATS++, March C, March C-, March X ,March Y, zero-one and checkerboard scan tests. PERL program is used to analyse the simulation results and a log file will be generated at the end of the memory test. Extensive simulation and experimental test results show that the memory tester modelled covers all the memory test algorithms used in the industry. The low-cost memory fault detection tester designed provides the 100% fault detection coverage for all memory defects.

Terrestrial free-space optical (FSO) communications is an emerging low-license-free and high-bandwidth access solution, albeit hampered by the combined effects from atmospheric loss, turbulence and pointing errors (PEs). Partially coherent beams (PCBs) are capable of mitigating the turbulence-induced signal fading and PEs, while causing reduction in the mean received signal intensity. This implies the necessity of PCB optimization technique, such that the trade-off between the reduction in the scintillation index and the decrease in the mean received irradiance can be achieved conveniently.\ud \ud This thesis investigates the performance of partially coherent FSO communication links from the information theory perspective. The important link design criteria are considered, and the Gaussian-Schell beam model is adopted to characterize the optical beam propagation through random turbulent medium. Numerical results show that beam width optimization presents a feasible approach in promoting capacity enhancement for long-distance terrestrial FSO systems, since the optimum beam width is susceptible to the deterring effects of atmospheric turbulence and PEs. Next, joint investigation of the effects of a PCB and aperture averaging is presented, which confirms the distinctive advantages of introducing an enlarged receiver aperture and the interest of optimizing the beam width to maximize the FSO channel capacity. A theoretical beam width optimization model is proposed to determine the optimum beam width. Subsequent investigation studies on the characteristics of PCB propagating through the turbulent channel reveal the relationship between the beam width and spatial coherence length to optimize the PCB. Therefore, a joint beam width and spatial coherence length optimization technique is proposed to maximize the average capacity in partially coherent FSO links. An optimization metric is developed to enable a feasible translation of the joint optimal transmitter beam parameters into an analogous level of divergence of the received optical beam. It is demonstrated that the PCBs are desirable in the weak-to-moderate turbulence regimes, whereas coherent laser beams with high transmit power exhibit greater resilience to strong turbulences.\ud \ud An experimental study is carried out to demonstrate the effects of aperture averaging and beam width on the FSO link under laboratory-controlled atmospheric turbulence conditions. The aperture-averaging effect is characterized through the signal density distributions, showing good agreement with the theoretical models. It is demonstrated that the relationship between the aperture averaging factor and point-received scintillation index can be described by a first-order linear regression model, whereby the coefficients of the model are provided and compared. Measurements of the Q-factor for an apertureaveraged\ud optical receiver and its corresponding finite point receiver reveals that manifold gain in the link performance can be achieved with increasing scaled aperture size, thus concluding that the introduction of an enlarged receiver aperture enhances the effective collection of the optical signal and potentially mitigates the scintillation effect.\ud \ud Atmospheric loss resulting from visibility-limiting weather conditions significantly attenuates the intensity of a propagating laser beam, which imposes degrading impacts on the link range and availability. Hybrid FSO and radio frequency (RF) systems present the most prominent alternative to enable these technologies in complementing one another’s weaknesses, since fog and rain drastically affect the FSO and RF links, respectively, but only insignificantly vice versa. The viability of deploying the media diversity technique in the FSO system is investigated through a case study, in which a new hybrid-base transceiver station (H-BTS) system architecture is proposed for the green Metrozones. The hybrid FSO/RF system is integrated at the macro-cellular tier, to enable high-capacity, power-efficient wireless backhauling. A resource prioritization mechanism is designed, to maintain good control and optimal on-demand resource allocation, and to establish sustainable backhaul link availability. Next, a basic access signalling (BAS) scheme is introduced, to necessitate the discovery, registration and monitoring of active metro access points (M-APs). The proposed BAS scheme enables the sleep-wake-on-demand (SWoD) mechanism and the cooperative inter-cell support. Findings from this work suggest that adaptation and optimization at the link- and system-level are vital for Metrozones deployment, due to the occurrence of numerous time-varying factors in real networks.