Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Smart capsules for sensing and sampling the gut: status, challenges and prospects(BMJ Publishing Group Ltd on behalf of the British Society of Gastroenterology, 2024-01) Rehan M; Al-Bahadly I; Thomas DG; Young W; Cheng LK; Avci ESmart capsules are developing at a tremendous pace with a promise to become effective clinical tools for the diagnosis and monitoring of gut health. This field emerged in the early 2000s with a successful translation of an endoscopic capsule from laboratory prototype to a commercially viable clinical device. Recently, this field has accelerated and expanded into various domains beyond imaging, including the measurement of gut physiological parameters such as temperature, pH, pressure and gas sensing, and the development of sampling devices for better insight into gut health. In this review, the status of smart capsules for sensing gut parameters is presented to provide a broad picture of these state-of-the-art devices while focusing on the technical and clinical challenges the devices need to overcome to realise their value in clinical settings. Smart capsules are developed to perform sensing operations throughout the length of the gut to better understand the body's response under various conditions. Furthermore, the prospects of such sensing devices are discussed that might help readers, especially health practitioners, to adapt to this inevitable transformation in healthcare. As a compliment to gut sensing smart capsules, significant amount of effort has been put into the development of robotic capsules to collect tissue biopsy and gut microbiota samples to perform in-depth analysis after capsule retrieval which will be a game changer for gut health diagnosis, and this advancement is also covered in this review. The expansion of smart capsules to robotic capsules for gut microbiota collection has opened new avenues for research with a great promise to revolutionise human health diagnosis, monitoring and intervention.Item Short-Term Wind Speed Forecasting Based on Hybrid MODWT-ARIMA-Markov Model(IEEE, 2021-06-08) Yousuf MU; Al-Bahadly I; Avci E; Do TDMarkov chains (MC) are statistical models used to predict very short to short-term wind speed accurately. Such models are generally trained with a single moving window. However, wind speed time series do not possess an equal length of behavior for all horizons. Therefore, a single moving window can provide reasonable estimates but is not an optimal choice. In this study, a forecasting model is proposed that integrates MCs with an adjusting dynamic moving window. The model selects the optimal size of the window based on a similar approach to the leave-one-out method. The traditional model is further optimized by introducing a self-adaptive state categorization algorithm. Instead of synthetically generating time series, the modified model directly predicts one-step ahead wind speed. Initial results indicate that adjusting the moving window MC prediction model improved the forecasting performance of a single moving window approach by 50%. Based on preliminary findings, a novel hybrid model is proposed integrating maximal overlap discrete wavelet transform (MODWT) with auto-regressive integrated moving average (ARIMA) and adjusting moving window MC. It is evident from the literature that MC models are suitable for predicting residual sequences. However, MCs were not considered as a primary forecasting model for the decomposition-based hybrid approach in any wind forecasting studies. The improvement of the novel model is, on average, 55% for single deep learning models and 30% for decomposition-based hybrid models.Item Wind speed prediction for small sample dataset using hybrid first-order accumulated generating operation-based double exponential smoothing model(John Wiley & Sons, Inc, 2022-03-09) Yousuf MU; Al-Bahadly I; Avci EWind power generation has recently emerged in many countries. Therefore, the availability of long-term historical wind speed data at various potential wind farm sites is limited. In these situations, such forecasting models are needed that comprehensively address the uncertainty of raw data based on small sample size. In this study, a hybrid first-order accumulated generating operation-based double exponential smoothing (AGO-HDES) model is proposed for very short-term wind speed forecasts. Firstly, the problems of traditional Holt's double exponential smoothing model are highlighted considering the wind speed data of Palmerston North, New Zealand. Next, three improvements are suggested for the traditional model with a rolling window of six data points. A mixed initialization method is introduced to improve the model performance. Finally, the superiority of the novel model is discussed by comparing the accuracy of the AGO-HDES model with other forecasting models. Results show that the AGO-HDES model increased the performance of the traditional model by 10%. Also, the modified model performed 7% better than other considered models with three times faster computational time.Item Towards Gut Microbiota Sampling Using an Untethered Sampling Device(IEEE, 2021-09-09) Rehan M; Al-Bahadly I; Thomas DG; Avci ERecent studies suggest that human gut microbiota can act as a bio-marker for human health. Also, it can function as a potential tool to understand stress and anxiety. However, the conventional tools have limitations acquiring samples of gut microbiota without contamination. In this work, an untethered robotic capsule prototype is developed that can actively collect the microbiota from the mucosa layer of the small intestine for the first time with the potential to avoid the upstream and downstream contamination. An analytical model for quantifying the peristaltic forces and developing two-way shape memory alloy spring actuator is presented. For the first time, a novel two-way shape memory alloy spring actuator (5 mm x \phi ~4 mm) is used to perform the sampling inside the gut. The spring actuator can apply 675 mN force, which is sufficient to perform in vivo sampling. A specialised experimental setup that can keep the freshly dissected intestine alive for 6 hours is utilised to test the robotic capsule. The robotic capsule prototype has collected an average of 200~\mu L and 112~\mu L sample from living pig duodenal and ileal tissues respectively i.e. in the presence of peristaltic forces. The robotic capsule was also tested on intestine of other species including cow and sheep and collected an average of 160~\mu L and 185~\mu L of content respectively from the living post-mortem tissues. The collected sample size for all the species is feasible to analyse the microbiota through next generation sequencing techniques. The experimental setup is a reliable proxy to in-vivo behaviour and the robotic capsule experimental result is promising in terms of in situ collection of microbiota.Item Development of a Robotic Capsule for in vivo Sampling of Gut Microbiota(Institute of Electrical and Electronics Engineers, 2022-10-01) Rehan M; Al-Bahadly I; Thomas DG; Avci EHuman gut microbiota can provide comprehensive information about the health of a host but the tools to collect microbiome samples are not currently available. A standalone wireless robotic capsule that has been developed in this study, collects the microbiota both from lumen (capsule surrounding) and intestinal wall (mucosa layer) for the first time. First, a two-way shape memory alloy (SMA) spring actuation system was developed by tackling the high-drain current requirement of SMAs. The actuator can produce up to 800 mN force that was sufficient to collect samples. Second, successful encapsulation of the collected sample to avoid contamination was realised by testing 3 main sealing materials. Third, the robotic capsule was tested in a gut simulator that mimics in-vivo environment to ensure successful and safe travel of the capsule along the gastrointestinal tract. Finally an in vitro experimental setup that keeps an intestine alive for 6 hours was used to optimise the sample collection. The capsule collected 128 μL and 107 μL samples (which are sufficient quantities for microbiome analysis) from duodenual and ileal tissues of a sheep. The proposed robotic capsule has a potential to become a vital apparatus for clinicians to sample human and animal gut in the future.Item Reliable Colour Detection for Matching Repaint Application(Scientific Research Publishing Inc, 31/01/2019) Al-Bahadly I; Wilkinson WThis paper presents the design and development of a system that creates the optimal conditions to sense colour for matching repaint application. The effectiveness of eliminating, and then recreating the lighting conditions to a desired level in a controlled enclosure is explored. The desired artificial light is introduced into the enclosure, providing optimal, constant conditions to measure surface reflectance. The tests conducted showed that the proposed system worked well. The testing results were good and showed that the relative results between samples taken at exactly the same location were an accurate match and consistent.Item An Integrated Wind and Hydro Power System Using Switched Reluctance Generators(Scientific Research Publishing Inc, 9/02/2018) Al-Bahadly IThis research work seeks to make renewable energy more reliable, cost effective, and accessible by exploring a different energy combination system to that currently applied to wind and hydro power. Instead of the usual electrical combination of wind and hydro generators, this work involved combining a water and wind turbine mechanically, before driving an electrical generator. This new combination system was modeled and optimized in MATLAB, using a direct combination system commonly found in multi-engine helicopters. The system was found to operate satisfactorily, however it is mechanically more complex than current electrical combining systems. Research was undertaken regarding wind and water resource availability, and the turbines were chosen with these taken into consideration. Various combination systems were explored, including torque and speed split mechanical combinations, conventional electrical combination, and using a modified switched reluctance generator as a method of electro-mechanical combination. The generator selected for this work is a three phase 12/8 Switched Reluctance (SR) machine. A detailed winding polarity having four poles per phase and their effect on the performance of the machine is observed.Item Portable Multi-Inputs Renewable Energy System for Small Scale Remote Application(Scientific Research Publishing Inc, 14/02/2018) Al-Bahadly IThis paper presents a potable renewable energy system. The portable renewable energy power unit is designed from a need. The need is for first response teams in remote natural disaster situations to have a reliable source of energy to power a small vaccine refrigerator or water purification system and a basic satellite communication system. It is important that such a need is explored as a practical solution has the potential to save the lives of people in remote areas, who would otherwise suffer from a lack of humanitarian aid. Currently diesel generators are the primary source of electricity generation for disaster responders and in most situations work very well and provide a sufficient amount of electricity to meet the power needs. However, in remote areas road infrastructure is often damaged. In this type of situation getting a constant supply of diesel to the area is an expensive or impractical operation. This is where the portable renewable energy power unit bridges the gap and allows a more practical solution to be implemented. The specific aim of the work is to design a compact, stand-alone, product that can be easily transported by people across uneven terrain. It can generate power from wind, solar and hydro energy sources. In this work a new non-isolated multiport DC-DC converter topology for a hybrid energy system in low power applications is proposed. The new topology assimilates multiple renewable energy sources and power up multiple loads with different output levels. A complete Solid works model and FEA analysis, on required components, is completed. The scope of the work encompasses both the electrical and mechanical design of the system.Item Enhancement of Wind Energy Conversion Using Axial Flux Generator(Scientific Research Publishing Inc, 25/02/2019) Al-Bahadly I; Neppalli SCThis paper investigates the application of the axial flux machine (AFM) to the wind energy conversion systems (WECS) to obtain high power and torque at reduced cost. By developing mathematical equations using the phase and active transformations, the three-phase model is transformed to two-phase equations by making both the stator and rotor as reference frames, finally converting to arbitrary reference frame, which is useful for the modelling of the axial flux machine. The torque, current, and voltage equations are expressed to improve the simulation reliability. Based on the developed equations, the mathematical model for the axial flux machine is developed using the MATLAB/Simulink. Starting with the axial flux motor model, when the load on the motor increases, how the parameters like torque, current, and speed of the motor vary are explored in this paper. Then for the axial flux generator model, when the wind speed exceeds the rated speed how the torque, line voltages, currents, power and speed of the generator behave are investigated and presented in this paper. The developed model in this paper could be extended to a twin-rotor axial flux synchronous machine, which will lead to the development of more efficient WECS.Item A comprehensive simulation platform for switched reluctance generator system(World Scientific and Engineering Academy and Society, 2012) Arifin A; Al-Bahadly I; Mukhopadhyay SC; Topalis, FV; Dias, EMA Switched Reluctance Generator (SRG) system normally encompasses three main components: SR machine, controller and converter. On-going research on simulation and modelling of SRG system has focused on one component. There is a lack of a more comprehensive approach which integrates all three components into one simulation platform. We have developed a simulation model comprising SR machine, control and converter using MATLAB/Simulink. The main advantage of a simulation model is to reduce time and cost by having to perform changes on the prototype machine. In this paper, the work is focused on developing the optimal control algorithm for the platform. Optimal parameters are identified and characterized in terms of highest percentage of power generated. From simulation, the most influential parameters affecting the power generated are the firing angles and voltage level. So, a function relating the optimized parameter with machine performance was developed. The proposed control technique will provide easy implementation and ensure high machine performance. The effectiveness of the proposed method is demonstrated by simulation results. The work will aid in development of SRG by providing a platform to determine the best generating operation before real implementation, reducing manufacturing time and cost.