Clement Asogwa - Academia.edu (original) (raw)

Papers by Clement Asogwa

Proceedings of the 9th International Conference on Body Area Networks, 2014

Galvanic coupled Intrabody communication signals use the human body as the waveguide. The signal ... more Galvanic coupled Intrabody communication signals use the human body as the waveguide. The signal characteristics change in gain and or loss by the body's physiological state. Because galvanic coupling contains the signal in the body, the technology can be suitable for finding alternative application in biomedical sciences. In this work, we investigate the use of a galvanic coupling circuit to study the hydration status of a human body from the changes in the signal characteristics. We show that below 5 MHz conductivity increases with hydration at the average rate of 0.24 dB/minute after fluid restriction from night to 10 am. During the process pre-hydration, hydration and post-hydration measurements were taken at 5, 10 and 15 minutes intervals. The measurements were taken after abstinence from fluid as stated above. Prior measurements of conductivity were taken at the stated intervals before fluid restriction as experimental control. Measurements of dehydration were taken after absorption has ceased and the subject urinated; it was observed that conductivity at dehydration decreased at the average rate of 0.92 dB/minute and the rate of hydration was quickest at 1.03 MHz while dehydration was fastest at 2.9 MHz.

Proceedings of the 9th International Conference on Body Area Networks, 2014

Intrabody communication (IBC) archetype is a novel healthcare network technology that enables non... more Intrabody communication (IBC) archetype is a novel healthcare network technology that enables non-RF based wireless data communication through the human body. The low-power IBC signals are confined to the body, making it suitable for transmitting health data of monitored vital human body signs such as heart-beat and blood pressure. Research in IBC communication usually focuses on channel characteristics for transceiver improvements in reliability, data rates and energy savings. In this paper we introduce a novel application of IBC galvanic coupling circuit for investigating human body composition. We compare empirical measurements using a vector network analyzer with circuit model simulations. The results show different attenuations observed for different proportions of the body tissue such as fat, muscle and bones. We found that a difference in body mass index (BMI) by 1 kg/m2 between the subjects results in approximately 1 dB increase in attenuation. Also, the signal attenuation increases with the BMI of the subjects but are also affected by their respective hydration states. We also found that frequencies above 5 MHz would not be suitable for estimating human body composition in a galvanic coupling IBC circuit. However, a wider experiment is required to give the range of data values that will correspond to attenuation for different body mass index by sex and age.

Tripping is the largest cause of falls and low swing foot ground clearance during the mid-swing p... more Tripping is the largest cause of falls and low swing foot ground clearance during the mid-swing phase, particularly at the critical gait event known as Minimum Foot Clearance (MFC) is the major risk factor for tripping-related falls. Intervention strategies to increase MFC height can be effective if applied in real-time based on feed-forward prediction. The current study investigated the capability of machine learning models to classify the MFC into various categories using toe-off kinematics data. Specifically, three MFC sub-categories (less than 1.5cm, between 1.5-2.0cm and higher than 2.0cm) were predicted applying machine learning approaches. A total of 18,490 swing phase gait cycles’ data were extracted from six healthy young adults, each walking for 5-minutes at a constant speed of 4km/h on a motorised treadmill. Both K-Nearest Neighbour (KNN) and Random-Forest were utilised for prediction based on the data from toe-off for five consecutive frames (0.025s duration). Foot kinem...

Sensors

Efficient, adaptive, locomotor function is critically important for maintaining our health and in... more Efficient, adaptive, locomotor function is critically important for maintaining our health and independence, but falls-related injuries when walking are a significant risk factor, particularly for more vulnerable populations such as older people and post-stroke individuals. Tripping is the leading cause of falls, and the swing-phase event Minimum Foot Clearance (MFC) is recognised as the key biomechanical determinant of tripping probability. MFC is defined as the minimum swing foot clearance, which is seen approximately mid-swing, and it is routinely measured in gait biomechanics laboratories using precise, high-speed, camera-based 3D motion capture systems. For practical intervention strategies designed to predict, and possibly assist, swing foot trajectory to prevent tripping, identification of the MFC event is essential; however, no technique is currently available to determine MFC timing in real-life settings outside the laboratory. One strategy has been to use wearable sensors,...

The study of human body hydration is increasingly leading to new practical applications, includin... more The study of human body hydration is increasingly leading to new practical applications, including online assessment techniques for whole body water level and novel techniques for real time assessment methods as well as characterization for fitness and exercise performance. In this review, we will discuss the different techniques for assessing hydration from electrical properties of tissues and their components and the biological relations between tissues. This will be done mainly in the context of engineering while highlighting some applications in medicine, mobile health and sports.

Intrabody signal propagation uses human body tissue as the communication medium. Human body tissu... more Intrabody signal propagation uses human body tissue as the communication medium. Human body tissue consists of various components in aqueous medium which are electrolytic in nature. Changes in the amount of water in the body changes the volume of the body fluid which in turn alters the overall impedance of the tissues. These changes affect the signal attenuation of an electrical signal passing through those tissues. We investigate the effect of body fluid changes on intrabody signal propagating between 900 kHz and 1.5 MHz. Our empirical measurements on 6 subjects show that within the first 20 minutes after intake of 600 ml of water, a propagating galvanic coupled signal would have maximum rate of signal gain occurring between 900 kHZ and 1.1 MHz. Understanding that rate at which the signal changes dues to changes in body fluid level can be used for investigating human body hydration patterns with potential application in diagnosing or monitoring body fluid disorder and diseases asso...

MEDICAL DEVICES & SENSORS, 2018

Increase in demand for quality health services at reduced cost has led to development in devices ... more Increase in demand for quality health services at reduced cost has led to development in devices that assist remote health monitoring without obstructing user's activities of daily living. In effect, real-time health monitoring technologies are breakthroughs in healthcare system (Lai, Begg, & Palaniswami, 2011). Technological developments have brought about dramatic changes in patient's diagnostic methods and monitoring locations from intensive units in hospitals to individual homes, care centres and respite places. Usually, medical diagnosis and pathological assessment involves monitoring physiological signs. Other signs monitored by individuals, sports physiologists and clinicians include changes in an individual's bone mass, hydration state, body fat and so on in relation to a recommended baseline. A main advantage of this new system is the ease and reduced cost of monitoring and follow-up. Outpatient monitoring has caused significant decrease in the high cost of prolonged hospital staying (Park & Jayaraman, 2010), enhanced close monitoring capability and improved early diagnosis and timely alert on patient's conditions (Custodio, Herrera, López, & Moreno, 2012).

Bioengineering

The success of deep machine learning (DML) models in gaming and robotics has increased its trial ... more The success of deep machine learning (DML) models in gaming and robotics has increased its trial in clinical and public healthcare solutions. In applying DML to healthcare problems, a special challenge of inadequate electrical energy and computing resources exists in regional and developing areas of the world. In this paper, we evaluate and report the computational and predictive performance design trade-offs for four candidate deep learning models that can be deployed for rapid malaria case finding. The goal is to maximise malaria detection accuracy while reducing computing resource and energy consumption. Based on our experimental results using a blood smear malaria test data set, the quantised versions of Basic Convolutional Neural Network (B-CNN) and MobileNetV2 have better malaria detection performance (up to 99% recall), lower memory usage (2MB 8-bit quantised model) and shorter inference time (33–95 microseconds on mobile phones) than VGG-19 fine-tuned and quantised models. H...

Electronics, Jun 15, 2017

Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling... more Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling of the body due to accumulation of tissue fluid on the affected area. Tissue fluid contains ions and electrolytes that affect electrical conductivity. The flow of tissue fluid helps to distribute vital nutrients and other important elements necessary for healthy living. When tissue fluid is stagnated, a high concentration of electrolytes accumulate on the affected area, which in turn affects an electrical signal passing through that area to be minimally attenuated in relation to a free-flowing fluid. We demonstrate that a galvanic coupled signal propagating along a lymphoedema affected limb could capture these changes by the amount of attenuation the propagating signal experiences in time. Our results show that average rate of signal attenuation on a lymphoedema affected part of the body could be as slow as 0.16 dB/min, while the rate of signal attenuation on a healthy part is as high as 1.83 dB/min. This means that fluid accumulation could slow down the exchange of body electrolytes up to twice less the rate on an unaffected contralateral part of the body. Monitoring these changes by observing the average rate of change of a galvanic coupled signal attenuation on the affected body part can be used for diagnosing early developments of oedema in the body and for evaluating recovery in response to treatment procedures.

Electronics, 2016

Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless... more Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless communication systems opened up the use of wearable technology for ehealth monitoring. We introduce a galvanic coupled intrabody communication for monitoring human body hydration. Studies in hydration provide the information necessary for understanding the desired fluid levels for optimal performance of the body's physiological and metabolic processes during exercise and activities of daily living. Current measurement techniques are mostly suitable for laboratory purposes due to their complexity and technical requirements. Less technical methods such as urine color observation and skin turgor testing are subjective and cannot be integrated into a wearable device. Bioelectrical impedance methods are popular but mostly used for estimating total body water with limited accuracy and sensitive to 800 mL-1000 mL change in body fluid levels. We introduce a non-intrusive and simple method of tracking hydration rates that can detect up to 1.30 dB reduction in attenuation when as little as 100 mL of water is consumed. Our results show that galvanic coupled intrabody signal propagation can provide qualitative hydration and dehydration rates in line with changes in an individual's urine specific gravity and body mass. The real-time changes in galvanic coupled intrabody signal attenuation can be integrated into wearable electronic devices to evaluate body fluid levels on a particular area of interest and can aid diagnosis and treatment of fluid disorders such as lymphoedema.

IEEE Transactions on Biomedical Engineering, 2015

Changes in human body hydration leading to excess fluid losses or overload affects the body fluid... more Changes in human body hydration leading to excess fluid losses or overload affects the body fluid's ability to provide the necessary support for healthy living. We propose a time dependent circuit model of real time human body hydration, which models the human body tissue as a signal transmission medium. The circuit model predicts the attenuation of a propagating electrical signal. Hydration rates are modelled by a time constant τ which characterises the individual specific metabolic function of the body part measured. We define a surrogate human body anthropometric parameter θ by the muscle-fat ratio and comparing it with the Body Mass Index (BMI), we find theoretically, the rate of hydration varying from 1.73 dB/minute, for high θ and low τ to 0.05 dB/minute for low θ and high τ. We compare these theoretical values with empirical measurements and show that real time changes in human body hydration can be observed by measuring signal attenuation. We took empirical measurements using a vector network analyser and obtained different hydration rates for various BMI, ranging from 0.6 dB/minute for 22.7 kg/m 2 down to 0.04 dB/minute for 41.2 kg/m 2. We conclude that the galvanic coupling circuit model can predict changes in the volume of the body fluid which are essential in diagnosing and monitoring treatment of body fluid disorder. Individuals with high BMI would have higher time-dependent biological characteristic, lower metabolic rate and lower rate of hydration.

International Journal of Advancements in Computing Technology, 2011

... he G rid scenario constructed by MO VE and si mulated o ur improved GPSR protocol in NS-2. Th... more ... he G rid scenario constructed by MO VE and si mulated o ur improved GPSR protocol in NS-2. The proposed protocol is compared with the traditional GPSR and AODV protocols, the performance indicates that our proposed protocol is very promising and ... [22] FK Karnadi, ZH Mo ...

Proceedings of the 9th International Conference on Body Area Networks, 2014

Galvanic coupled Intrabody communication signals use the human body as the waveguide. The signal ... more Galvanic coupled Intrabody communication signals use the human body as the waveguide. The signal characteristics change in gain and or loss by the body's physiological state. Because galvanic coupling contains the signal in the body, the technology can be suitable for finding alternative application in biomedical sciences. In this work, we investigate the use of a galvanic coupling circuit to study the hydration status of a human body from the changes in the signal characteristics. We show that below 5 MHz conductivity increases with hydration at the average rate of 0.24 dB/minute after fluid restriction from night to 10 am. During the process pre-hydration, hydration and post-hydration measurements were taken at 5, 10 and 15 minutes intervals. The measurements were taken after abstinence from fluid as stated above. Prior measurements of conductivity were taken at the stated intervals before fluid restriction as experimental control. Measurements of dehydration were taken after absorption has ceased and the subject urinated; it was observed that conductivity at dehydration decreased at the average rate of 0.92 dB/minute and the rate of hydration was quickest at 1.03 MHz while dehydration was fastest at 2.9 MHz.

Proceedings of the 9th International Conference on Body Area Networks, 2014

Intrabody communication (IBC) archetype is a novel healthcare network technology that enables non... more Intrabody communication (IBC) archetype is a novel healthcare network technology that enables non-RF based wireless data communication through the human body. The low-power IBC signals are confined to the body, making it suitable for transmitting health data of monitored vital human body signs such as heart-beat and blood pressure. Research in IBC communication usually focuses on channel characteristics for transceiver improvements in reliability, data rates and energy savings. In this paper we introduce a novel application of IBC galvanic coupling circuit for investigating human body composition. We compare empirical measurements using a vector network analyzer with circuit model simulations. The results show different attenuations observed for different proportions of the body tissue such as fat, muscle and bones. We found that a difference in body mass index (BMI) by 1 kg/m2 between the subjects results in approximately 1 dB increase in attenuation. Also, the signal attenuation increases with the BMI of the subjects but are also affected by their respective hydration states. We also found that frequencies above 5 MHz would not be suitable for estimating human body composition in a galvanic coupling IBC circuit. However, a wider experiment is required to give the range of data values that will correspond to attenuation for different body mass index by sex and age.

Tripping is the largest cause of falls and low swing foot ground clearance during the mid-swing p... more Tripping is the largest cause of falls and low swing foot ground clearance during the mid-swing phase, particularly at the critical gait event known as Minimum Foot Clearance (MFC) is the major risk factor for tripping-related falls. Intervention strategies to increase MFC height can be effective if applied in real-time based on feed-forward prediction. The current study investigated the capability of machine learning models to classify the MFC into various categories using toe-off kinematics data. Specifically, three MFC sub-categories (less than 1.5cm, between 1.5-2.0cm and higher than 2.0cm) were predicted applying machine learning approaches. A total of 18,490 swing phase gait cycles’ data were extracted from six healthy young adults, each walking for 5-minutes at a constant speed of 4km/h on a motorised treadmill. Both K-Nearest Neighbour (KNN) and Random-Forest were utilised for prediction based on the data from toe-off for five consecutive frames (0.025s duration). Foot kinem...

Sensors

Efficient, adaptive, locomotor function is critically important for maintaining our health and in... more Efficient, adaptive, locomotor function is critically important for maintaining our health and independence, but falls-related injuries when walking are a significant risk factor, particularly for more vulnerable populations such as older people and post-stroke individuals. Tripping is the leading cause of falls, and the swing-phase event Minimum Foot Clearance (MFC) is recognised as the key biomechanical determinant of tripping probability. MFC is defined as the minimum swing foot clearance, which is seen approximately mid-swing, and it is routinely measured in gait biomechanics laboratories using precise, high-speed, camera-based 3D motion capture systems. For practical intervention strategies designed to predict, and possibly assist, swing foot trajectory to prevent tripping, identification of the MFC event is essential; however, no technique is currently available to determine MFC timing in real-life settings outside the laboratory. One strategy has been to use wearable sensors,...

The study of human body hydration is increasingly leading to new practical applications, includin... more The study of human body hydration is increasingly leading to new practical applications, including online assessment techniques for whole body water level and novel techniques for real time assessment methods as well as characterization for fitness and exercise performance. In this review, we will discuss the different techniques for assessing hydration from electrical properties of tissues and their components and the biological relations between tissues. This will be done mainly in the context of engineering while highlighting some applications in medicine, mobile health and sports.

Intrabody signal propagation uses human body tissue as the communication medium. Human body tissu... more Intrabody signal propagation uses human body tissue as the communication medium. Human body tissue consists of various components in aqueous medium which are electrolytic in nature. Changes in the amount of water in the body changes the volume of the body fluid which in turn alters the overall impedance of the tissues. These changes affect the signal attenuation of an electrical signal passing through those tissues. We investigate the effect of body fluid changes on intrabody signal propagating between 900 kHz and 1.5 MHz. Our empirical measurements on 6 subjects show that within the first 20 minutes after intake of 600 ml of water, a propagating galvanic coupled signal would have maximum rate of signal gain occurring between 900 kHZ and 1.1 MHz. Understanding that rate at which the signal changes dues to changes in body fluid level can be used for investigating human body hydration patterns with potential application in diagnosing or monitoring body fluid disorder and diseases asso...

MEDICAL DEVICES & SENSORS, 2018

Increase in demand for quality health services at reduced cost has led to development in devices ... more Increase in demand for quality health services at reduced cost has led to development in devices that assist remote health monitoring without obstructing user's activities of daily living. In effect, real-time health monitoring technologies are breakthroughs in healthcare system (Lai, Begg, & Palaniswami, 2011). Technological developments have brought about dramatic changes in patient's diagnostic methods and monitoring locations from intensive units in hospitals to individual homes, care centres and respite places. Usually, medical diagnosis and pathological assessment involves monitoring physiological signs. Other signs monitored by individuals, sports physiologists and clinicians include changes in an individual's bone mass, hydration state, body fat and so on in relation to a recommended baseline. A main advantage of this new system is the ease and reduced cost of monitoring and follow-up. Outpatient monitoring has caused significant decrease in the high cost of prolonged hospital staying (Park & Jayaraman, 2010), enhanced close monitoring capability and improved early diagnosis and timely alert on patient's conditions (Custodio, Herrera, López, & Moreno, 2012).

Bioengineering

The success of deep machine learning (DML) models in gaming and robotics has increased its trial ... more The success of deep machine learning (DML) models in gaming and robotics has increased its trial in clinical and public healthcare solutions. In applying DML to healthcare problems, a special challenge of inadequate electrical energy and computing resources exists in regional and developing areas of the world. In this paper, we evaluate and report the computational and predictive performance design trade-offs for four candidate deep learning models that can be deployed for rapid malaria case finding. The goal is to maximise malaria detection accuracy while reducing computing resource and energy consumption. Based on our experimental results using a blood smear malaria test data set, the quantised versions of Basic Convolutional Neural Network (B-CNN) and MobileNetV2 have better malaria detection performance (up to 99% recall), lower memory usage (2MB 8-bit quantised model) and shorter inference time (33–95 microseconds on mobile phones) than VGG-19 fine-tuned and quantised models. H...

Electronics, Jun 15, 2017

Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling... more Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling of the body due to accumulation of tissue fluid on the affected area. Tissue fluid contains ions and electrolytes that affect electrical conductivity. The flow of tissue fluid helps to distribute vital nutrients and other important elements necessary for healthy living. When tissue fluid is stagnated, a high concentration of electrolytes accumulate on the affected area, which in turn affects an electrical signal passing through that area to be minimally attenuated in relation to a free-flowing fluid. We demonstrate that a galvanic coupled signal propagating along a lymphoedema affected limb could capture these changes by the amount of attenuation the propagating signal experiences in time. Our results show that average rate of signal attenuation on a lymphoedema affected part of the body could be as slow as 0.16 dB/min, while the rate of signal attenuation on a healthy part is as high as 1.83 dB/min. This means that fluid accumulation could slow down the exchange of body electrolytes up to twice less the rate on an unaffected contralateral part of the body. Monitoring these changes by observing the average rate of change of a galvanic coupled signal attenuation on the affected body part can be used for diagnosing early developments of oedema in the body and for evaluating recovery in response to treatment procedures.

Electronics, 2016

Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless... more Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless communication systems opened up the use of wearable technology for ehealth monitoring. We introduce a galvanic coupled intrabody communication for monitoring human body hydration. Studies in hydration provide the information necessary for understanding the desired fluid levels for optimal performance of the body's physiological and metabolic processes during exercise and activities of daily living. Current measurement techniques are mostly suitable for laboratory purposes due to their complexity and technical requirements. Less technical methods such as urine color observation and skin turgor testing are subjective and cannot be integrated into a wearable device. Bioelectrical impedance methods are popular but mostly used for estimating total body water with limited accuracy and sensitive to 800 mL-1000 mL change in body fluid levels. We introduce a non-intrusive and simple method of tracking hydration rates that can detect up to 1.30 dB reduction in attenuation when as little as 100 mL of water is consumed. Our results show that galvanic coupled intrabody signal propagation can provide qualitative hydration and dehydration rates in line with changes in an individual's urine specific gravity and body mass. The real-time changes in galvanic coupled intrabody signal attenuation can be integrated into wearable electronic devices to evaluate body fluid levels on a particular area of interest and can aid diagnosis and treatment of fluid disorders such as lymphoedema.

IEEE Transactions on Biomedical Engineering, 2015

Changes in human body hydration leading to excess fluid losses or overload affects the body fluid... more Changes in human body hydration leading to excess fluid losses or overload affects the body fluid's ability to provide the necessary support for healthy living. We propose a time dependent circuit model of real time human body hydration, which models the human body tissue as a signal transmission medium. The circuit model predicts the attenuation of a propagating electrical signal. Hydration rates are modelled by a time constant τ which characterises the individual specific metabolic function of the body part measured. We define a surrogate human body anthropometric parameter θ by the muscle-fat ratio and comparing it with the Body Mass Index (BMI), we find theoretically, the rate of hydration varying from 1.73 dB/minute, for high θ and low τ to 0.05 dB/minute for low θ and high τ. We compare these theoretical values with empirical measurements and show that real time changes in human body hydration can be observed by measuring signal attenuation. We took empirical measurements using a vector network analyser and obtained different hydration rates for various BMI, ranging from 0.6 dB/minute for 22.7 kg/m 2 down to 0.04 dB/minute for 41.2 kg/m 2. We conclude that the galvanic coupling circuit model can predict changes in the volume of the body fluid which are essential in diagnosing and monitoring treatment of body fluid disorder. Individuals with high BMI would have higher time-dependent biological characteristic, lower metabolic rate and lower rate of hydration.

International Journal of Advancements in Computing Technology, 2011

... he G rid scenario constructed by MO VE and si mulated o ur improved GPSR protocol in NS-2. Th... more ... he G rid scenario constructed by MO VE and si mulated o ur improved GPSR protocol in NS-2. The proposed protocol is compared with the traditional GPSR and AODV protocols, the performance indicates that our proposed protocol is very promising and ... [22] FK Karnadi, ZH Mo ...