Graphical abstract Abstract Atrial fibrillation (AF) has been widely stated as the most common ar... more Graphical abstract Abstract Atrial fibrillation (AF) has been widely stated as the most common arrhythmias (irregularities of heart rhythm) which could lead to severe heart problem such as stroke. Many studies have been conducted to understand and explain its mechanism by analyzing its signal, in either time domain or frequency domain. This paper aims to provide basic information on the AF by reviewing relevant papers. Overall, this paper will provide review on the underlying theory of AF, AF mechanism as well as the common relevant signal processing steps and analysis.
There are various types of micro-scale energy harvesters (EH) that have been reported by many res... more There are various types of micro-scale energy harvesters (EH) that have been reported by many researchers around the world such as photovoltaic cells, piezoelectric transducers, electromagnetic transducers, thermoelectric and others. Energy harvester that harvest ambient energy which exists naturally or produced by mankind or machines, are able to be an alternative source for low-power devices such as mobile phone, laptop, health implant and many more. Thermoelectric is an energy harvester that converts heat waste from any sources such as vehicle engines, laptops or human body into electricity. Numerous kind of thermoelectric materials including metals and semiconductors have been investigated by researchers that produce different performances and efficiencies. Recently, researchers are looking forward to nanostructured semiconductors such as nanoribbons, nanotubes, nanowires and quantum dots as a potential to increase the figure of merit (ZT) and efficiency of thermoelectric EH. This paper reviews on silicon as the second most abundant element on earth and commonly used in electronic components is possible to be used as thermoelectric material. Silicon in bulk has high thermal conductivity which is less desirable for thermoelectric application. However, many studies regarding nanostructured silicon such as silicon nanowires have been carried out with promising results in reducing thermal conductivity.
Journal of Biomedical Science and Engineering, 2010
Dominant frequency (DF) of electrophysiological data is an effective approach to estimate the act... more Dominant frequency (DF) of electrophysiological data is an effective approach to estimate the activation rate during Atrial Fibrillation (AF) and it is important to understand the pathophysiology of AF and to help select candidate sites for ablation. Frequency analysis is used to find and track DF. It is important to minimize the catheter insertion time in the atria as it contributes to the risk for the patients during this procedure, so DF estimation needs to be obtained as quickly as possible. A comparison of computation times taken for spectrum estimation analysis is presented in this paper. Fast Fourier Transform (FFT), Blackman-Tukey (BT), Autoregressive (AR) and Multiple Signal Classification (MUSIC) methods are used to obtain the frequency spectrum of the signals. The time to produce DF was measured for each method. The method which takes the shortest time for analysis is selected for real time application purpose.
Electrical capacitance tomography (ECT) system is useful to obtain information on spatial distrib... more Electrical capacitance tomography (ECT) system is useful to obtain information on spatial distribution of dielectric material mixture inside a vessel. This paper discusses a sixteen-electrode mobile ECT sensing system which is developed non-invasively and non-intrusively. Emphases on the software development aspects are presented in several sections; initialization part, normalization part, calibration part, hardware communication part and the image reconstruction part. Thus, the liquid-gas concentration profile of the ECT system is successfully acquired using the software developed.
Electrical methods have been widely used in geophysical surveying to obtain high-resolution infor... more Electrical methods have been widely used in geophysical surveying to obtain high-resolution information about subsurface conditions, since the last few decades. Resistivity is an important parameter in judging the ground properties, especially detecting buried objects of anomalous conductivity. Electrical DC (i.e. Direct Current) resistivity sounding is the commonly used technique to obtain the apparent 2-D resistivity of the region under investigation. Acquiring the true resistivity from collected data remains a complex task due to nonlinearity particularly due to contrasts distributed in the region. In this work, a radial basis function neural network (RBFNN) metamodelling approach is proposed to solve the 2-D resistivity inverse problem. The model was trained with synthetic data samples obtained for a homogeneous medium of 100Ω.m. The neural network was then tested on another set of synthetic data. The results show the ability of the proposed approach to estimate the true resistivity from the 2-D apparent resistivity sounding data with high correlation. The proposed technique, when executed, appears to be computationally-efficient, as it requires less processing time and produces less error than conventional method.
Traffic light breakdown is very common. These create hassle as well as unsafe condition for road ... more Traffic light breakdown is very common. These create hassle as well as unsafe condition for road users. This project provides a new paradigm in traffic light monitoring system. The system has the capability to send multiple Short Message Service (SMS) to the contractor, traffic police and local council in the event of a malfunction traffic light. Normally, road users have to call the contractor based on the information displayed at the traffic light pole. With the current system, time taken to respond to the traffic light breakdown depends on how soon road users call the contractor. Monitoring system for fault traffic light will address this matter. In this project, the system can detect two types of failure, power failure and bulb/ Light Emitting Diode (LED) failure (a particular light not working i.e. red light only). Upon receiving the power failure signal, SMS will be sent to the above-mentioned parties for further action. For LED types of traffic light, the system has the capability to detect deterioration in function. If >50% of the LED for any light is not working the system will notify the contractor and other related parties to perform restorative action. The malfunction of LED can be detected by measuring real current vs the nominal current for that particular light. The seriousness of traffic light failure is divided into three parts, which are the total power failure, total LED failure and partial failure. The microcontroller analyzes the seriousness of the failure and sends the signal to a Global System for Mobile communications (GSM) module. Then the GSM module will send the details of failure including location and types of failure. For this project, LED was used as prototype of the traffic light.
Graphical abstract Abstract Atrial fibrillation (AF) has been widely stated as the most common ar... more Graphical abstract Abstract Atrial fibrillation (AF) has been widely stated as the most common arrhythmias (irregularities of heart rhythm) which could lead to severe heart problem such as stroke. Many studies have been conducted to understand and explain its mechanism by analyzing its signal, in either time domain or frequency domain. This paper aims to provide basic information on the AF by reviewing relevant papers. Overall, this paper will provide review on the underlying theory of AF, AF mechanism as well as the common relevant signal processing steps and analysis.
There are various types of micro-scale energy harvesters (EH) that have been reported by many res... more There are various types of micro-scale energy harvesters (EH) that have been reported by many researchers around the world such as photovoltaic cells, piezoelectric transducers, electromagnetic transducers, thermoelectric and others. Energy harvester that harvest ambient energy which exists naturally or produced by mankind or machines, are able to be an alternative source for low-power devices such as mobile phone, laptop, health implant and many more. Thermoelectric is an energy harvester that converts heat waste from any sources such as vehicle engines, laptops or human body into electricity. Numerous kind of thermoelectric materials including metals and semiconductors have been investigated by researchers that produce different performances and efficiencies. Recently, researchers are looking forward to nanostructured semiconductors such as nanoribbons, nanotubes, nanowires and quantum dots as a potential to increase the figure of merit (ZT) and efficiency of thermoelectric EH. This paper reviews on silicon as the second most abundant element on earth and commonly used in electronic components is possible to be used as thermoelectric material. Silicon in bulk has high thermal conductivity which is less desirable for thermoelectric application. However, many studies regarding nanostructured silicon such as silicon nanowires have been carried out with promising results in reducing thermal conductivity.
Journal of Biomedical Science and Engineering, 2010
Dominant frequency (DF) of electrophysiological data is an effective approach to estimate the act... more Dominant frequency (DF) of electrophysiological data is an effective approach to estimate the activation rate during Atrial Fibrillation (AF) and it is important to understand the pathophysiology of AF and to help select candidate sites for ablation. Frequency analysis is used to find and track DF. It is important to minimize the catheter insertion time in the atria as it contributes to the risk for the patients during this procedure, so DF estimation needs to be obtained as quickly as possible. A comparison of computation times taken for spectrum estimation analysis is presented in this paper. Fast Fourier Transform (FFT), Blackman-Tukey (BT), Autoregressive (AR) and Multiple Signal Classification (MUSIC) methods are used to obtain the frequency spectrum of the signals. The time to produce DF was measured for each method. The method which takes the shortest time for analysis is selected for real time application purpose.
Electrical capacitance tomography (ECT) system is useful to obtain information on spatial distrib... more Electrical capacitance tomography (ECT) system is useful to obtain information on spatial distribution of dielectric material mixture inside a vessel. This paper discusses a sixteen-electrode mobile ECT sensing system which is developed non-invasively and non-intrusively. Emphases on the software development aspects are presented in several sections; initialization part, normalization part, calibration part, hardware communication part and the image reconstruction part. Thus, the liquid-gas concentration profile of the ECT system is successfully acquired using the software developed.
Electrical methods have been widely used in geophysical surveying to obtain high-resolution infor... more Electrical methods have been widely used in geophysical surveying to obtain high-resolution information about subsurface conditions, since the last few decades. Resistivity is an important parameter in judging the ground properties, especially detecting buried objects of anomalous conductivity. Electrical DC (i.e. Direct Current) resistivity sounding is the commonly used technique to obtain the apparent 2-D resistivity of the region under investigation. Acquiring the true resistivity from collected data remains a complex task due to nonlinearity particularly due to contrasts distributed in the region. In this work, a radial basis function neural network (RBFNN) metamodelling approach is proposed to solve the 2-D resistivity inverse problem. The model was trained with synthetic data samples obtained for a homogeneous medium of 100Ω.m. The neural network was then tested on another set of synthetic data. The results show the ability of the proposed approach to estimate the true resistivity from the 2-D apparent resistivity sounding data with high correlation. The proposed technique, when executed, appears to be computationally-efficient, as it requires less processing time and produces less error than conventional method.
Traffic light breakdown is very common. These create hassle as well as unsafe condition for road ... more Traffic light breakdown is very common. These create hassle as well as unsafe condition for road users. This project provides a new paradigm in traffic light monitoring system. The system has the capability to send multiple Short Message Service (SMS) to the contractor, traffic police and local council in the event of a malfunction traffic light. Normally, road users have to call the contractor based on the information displayed at the traffic light pole. With the current system, time taken to respond to the traffic light breakdown depends on how soon road users call the contractor. Monitoring system for fault traffic light will address this matter. In this project, the system can detect two types of failure, power failure and bulb/ Light Emitting Diode (LED) failure (a particular light not working i.e. red light only). Upon receiving the power failure signal, SMS will be sent to the above-mentioned parties for further action. For LED types of traffic light, the system has the capability to detect deterioration in function. If >50% of the LED for any light is not working the system will notify the contractor and other related parties to perform restorative action. The malfunction of LED can be detected by measuring real current vs the nominal current for that particular light. The seriousness of traffic light failure is divided into three parts, which are the total power failure, total LED failure and partial failure. The microcontroller analyzes the seriousness of the failure and sends the signal to a Global System for Mobile communications (GSM) module. Then the GSM module will send the details of failure including location and types of failure. For this project, LED was used as prototype of the traffic light.
Uploads
Papers by Anita Ahmad