This paper presents a comparative analysis of the zero-voltage zero-current switching (ZVZCS) sof... more This paper presents a comparative analysis of the zero-voltage zero-current switching (ZVZCS) soft switching technique with zero-voltage switching (ZVS) and zero-current switching (ZCS) counterparts. The generalization of the voltage–current crossover or the energy loss factor obtained from simulation of the prototype converter shows that the ZVZCS significantly reduces the losses and helps to improve the efficiency of the converter as compared to the ZVS or the ZCS. On the other hand, it is also found that the soft switching range of operation of the ZVS and the ZCS is largely affected by the maximum switch voltage and switch current, respectively. In contrast, these factors have a negligible effect on the ZVZCS operation which results in an extended range of soft switching operation. Additionally, a detailed PSPICE simulation is performed for selected ZVS, ZCS, and ZVZCS topologies from the recent literature, and the switching losses in the main switches of the converters are meas...
This paper presents an analysis and modeling of the class-E inverter for ZVS/ZVDS execution at an... more This paper presents an analysis and modeling of the class-E inverter for ZVS/ZVDS execution at any duty ratio. The methodology is to determine the input current to the inverter analytically under the assumption that it always remains positive. The latter is ensured by proper selection of the input inductance such that the inverter always operates either in (1) the border condition mode or in (2) the continuous conduction mode regardless of the input ripple. Using this input current and applying the boundary conditions, the required input capacitance for the ZVS/ZVDS execution is determined at a specified input/output voltage, output power and load. The analysis shows that the ZVS/ZVDS can be achieved while the input capacitance is selected appropriately. A comparison between the analytical and simulation results is also formulated involving the proposed and other existing models. The simulation results that are provided at different duty ratios demonstrate that they are in a better ...
This paper presents a comparative analysis of the class E and selected enhanced class E inverters... more This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL). To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter. More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E...
Smart Grid technology as a platform can encompass several advanced technological features across ... more Smart Grid technology as a platform can encompass several advanced technological features across the spectrum of the power system. Smart Grid may introduce an early warning system for structural damage on the surface of large-scale power utility facilities providing crucial information to maintain the safety of the plant. To achieve such a cost-effective structural health monitoring system, a holistic smart inspection implementation framework is required. Using recently available sophisticated inspection technologies, high-resolution images covering the structural condition of large infrastructure can be routinely acquired as a remote monitoring process. Automated analysis of these inspection images can significantly reduce the inspection cost, provide an effective detection mechanism, and shorten reporting time, as a result, reducing overall maintenance costs, and improving safety measures. In this work, we have applied state of art deep learning based inspection image analysis methods for surface damage detection of various renewable energy power plants with a single unified model. We have achieved the state-of-the-art accuracy of 0.79 mean average precision on average even where input images are of varied modalities: from thermal images to visual images, from high-to low-resolution images, and from PV panels to wind turbines. All variations have been tackled with one single deep learning model to detect surface damages. Our results demonstrate the promise of effectively deploying a single trained model to inspect a wide range of energy installations while reducing the monitoring cost significantly. In addition, this work also published the reported dataset comprising four specific image sets for the research community.
Abstract Enhanced sustainability and efficiency are among the prime indicators to achieve in the ... more Abstract Enhanced sustainability and efficiency are among the prime indicators to achieve in the power generation sector of any country. The decline in efficiency might be caused by improper utilization of fuels and increasing entropy in outdated generation units. Reduced efficiency in power generation is particularly detrimental for the sustainability in developing countries, as resources are limited and need to be carefully allocated and maintained. Exergy analysis based on the laws of thermodynamics are currently gaining traction among researchers to study the overall performances of power generation units. Taking Bangladesh as a case study, this work investigates the power generation data for the country since 2009 till 2019 to study the internal energy losses of natural gas, oil, high-speed diesel, coal, and hydro based plants and provides a baseline for investment policy formulation. Our study found that, due to lack of maintenance and proper planning during the initial phases, the overall energy efficiencies among these sectors are relatively low, staying in the range of 34.55%–36.1% while the exergy efficiencies are 35.07%–36.59%. Corresponding exergetic parameters as depletion number, exergy sustainability index, relative irreversibility, lack of production, cumulative exergy loss, waste exergy ratio, and environmental effect factor pointed to similar findings in terms of sustainability as well. Comparing these parameters, it is observed that hydroelectric plants are more sustainable and efficient compared to fossil fuel-based generation units. Cost estimation of fuels and financial losses in the power generation sector are also explored for a better understanding of the return on investment.
Daylight utilization is one of the key areas for energy savings in indoor environments. An import... more Daylight utilization is one of the key areas for energy savings in indoor environments. An important factor often not considered by the existing daylight utilization approaches is the segregation of the floor into task areas and non-task areas. It is also observed that the inherent asymmetry in the daylight penetration pattern in most indoor environments is not given consideration while designing artificial lighting arrangements. Moreover, daily and annual daylight availability is found to have a symmetrical variation pattern, which is a significant factor often overlooked in utilizing daylight. Thus, the energy assessment can be inaccurate, leading to an incorrect or impractical evaluation of energy savings. This research proposes a comprehensive new approach to assess the energy-saving potential of daylight utilization in indoor environments. This new method combines two approaches to overcome the aforementioned issues. (1) The considered area is segmented into task area and non-t...
Journal of Research in Engineering and Applied Sciences, 2018
The main challenge today is to promote the development and commercialization of renewable energy ... more The main challenge today is to promote the development and commercialization of renewable energy sources for widespread adaption. This requires a smooth transition from fossil fuel based generation system to renewable energy supported system. The two main obstacles in this regard are efficiency constraint and cost of renewable sources. Photovoltaic systems are one of the most promising and prominent candidates of emerging renewable sources. Lack of capability of bulk production of energy, system efficiency, availability, reliability, feasibility, sustainability, suitable geographical sites, lifetime, capital cost/investment, commercialization, energy storage, complex manufacturing process and finally cost of energy are the major factors affecting the growth of renewable sources like photovoltaic energy system. Improved performance and cost reduction can increase the use and popularity of the sources.
His research interests are semiconductor A c c e p t e d M a n u s c r i p t device modeling, mat... more His research interests are semiconductor A c c e p t e d M a n u s c r i p t device modeling, material characterization and low power TCAM circuits. He has authored and co-authored several papers published in international conference proceedings and refereed journals. He is a member of IEEE. A c c e p t e d M a n u s c r i p t Review and Comparative Study of I-V Characteristics of Different Memristor Models with Sinusoidal Input Memory-resistor (Memristor) has drawn considerable attention of the researchers in the last decade due to its remarkable properties. After the first concept of memristor, proposed by Leon Chua in 1971, almost no research work was conducted in this field for a long time. However, since the revolutionary discovery of the physical structure of memristor and its model of the HP lab in 2008, a tremendous amount of research work has been going on. Researchers are focusing on improving the models for the analysis of the memristor. Different researchers have come up with their model to improve the existing ones. These models can be linear, nonlinear or exponential. To overcome the boundary problem, many window functions have been proposed. Different models have their explanations of voltage-current relationship and state variable derivatives. This paper presents a detailed review and a comparative study of the existing memristor models based on their I-V characteristic curve. Original experimental I-V curve from the HP lab has been used as the reference for comparison.
Body-channel communication (BCC) is based on the principle of electrical field data transmission ... more Body-channel communication (BCC) is based on the principle of electrical field data transmission attributable to capacitive coupling through the human body. It is gaining importance now a day in the scenario of human centric communication because it truly offers a natural means of interaction with the human body. Traditionally, near field communication (NFC) considers as a magnetic field coupling based on radio frequency identification (RFID) technology. The RFID technology also limits the definition of NFC and thus reduces the scope of a wide range of applications. In recent years BCC, after its first origin in 1995, regain importance with its valuable application in biomedical systems. Primarily, KAIST and Philips research groups demonstrate BCC in the context of biomedical remote patient health monitoring system. BCC transceiver mainly consists of two parts: one is digital baseband and the other is an analog front end (AFE). In this thesis, an analog front end receiver has presented to support the overall BCC. The receiver (Rx) architecture consists of cascaded preamplifier and Schmitt trigger. When the signals are coming from the human body, they are attenuated around 60 dB and gives weak signals in the range of mV. A high gain preamplifier stage needs to amplify these weak signals and make them as strong signals. The preamplifier single stage needs to cascade for the gain requirement. The single stage preamplifier, which is designed with ST65 nm technology, has an open loop gain of 24.01 dB and close loop gain of 19.43 dB. A flipped voltage follower (FVF) topology is used for designing this preamplifier to support the low supply voltage of 1 V because the topology supports low voltage, low noise and also low power consumption. The input-referred noise is 8.69 nV/sqrt(Hz) and the SNR at the input are 73.26 dB. The Schmitt trigger (comparator with hysteresis) is a bistable positive feedback circuit. It builds around two stage OTA with lead frequency compensation. The DC gain for this OTA is 26.94 dB with 1 V supply voltage. The corner analyzes and eye diagram as a performance matrix for the overall receiver are also included in this thesis work. 4 An Input Amplifier for Body-Channel Communication Acknowledgments Firstly I want to thank Almighty Allah for giving me an opportunity to study at the Linköping University and meet some nice people over here.
2014 International Conference on Electrical Engineering and Information & Communication Technology, 2014
ABSTRACT This paper presents a newly cascaded voltage mode tri-state driver circuit for body-coup... more ABSTRACT This paper presents a newly cascaded voltage mode tri-state driver circuit for body-coupled communication (BCC) designed in 65 nm CMOS technology. Each stage of the driver circuit has been resized to meet the requirement of the BCC. It has a driving capability of 6 mA from 1.2 V supply with 10 MHz operating frequency. Different analysis has been performed to get the optimum results for the proposed circuit. The analysis shows cycle to cycle jitter to be less than one and power supply rejection ratio (PSRR) 65 dB, indicating the good emission of supply noise. In addition, the driver circuit does not require a filter to emit the noise because the body acts like a low pass filter.
2014 International Conference on Informatics, Electronics & Vision (ICIEV), 2014
The paper presents performance analysis of an analog front end (AFE) for body-coupled communicati... more The paper presents performance analysis of an analog front end (AFE) for body-coupled communication (BCC) which is based on data transmission via capacitive coupling through the human body. The AFE designs by cascading differential preamplifier and Schmitt trigger. A flipped voltage follower (FVF) topology is used as part of the preamplifier design. The operation frequency of the overall system is mentioned as 10 MHz. The open loop gain is 24.01 dB and the close loop gain is 19.43 dB for this preamplifier. The input referred noise PSD is 8.69 nV/√Hz at 10 MHz. The system runs on a supply voltage of 1 V with implementation being done on 65 nm CMOS technology.
2011 IEEE Symposium on Industrial Electronics and Applications, 2011
Abstract The paper shows the implementation of digital circuit design using ultra-low power logic... more Abstract The paper shows the implementation of digital circuit design using ultra-low power logic components. Fundamentals of Source coupled logic (SCL) gates are used with running at sub-threshold regime with the purpose of achieving low power consumption while ...
Oral condyloma acuminatum or venereal wart is an infectious disease o f the oral mucosa caused by... more Oral condyloma acuminatum or venereal wart is an infectious disease o f the oral mucosa caused by a virus similar or identical to that causing Verrucae vulgaris and plantaris. I t consists of papillomatous projections with marked parakeratosis or keratosis and acanthotic epithelial downgrowlhs. Vacuolated cells are often a feature o f the stratum spinosum. Criteria for the differential diagnosis and surgical management of this condition are presented.
This paper presents a comparative analysis of the zero-voltage zero-current switching (ZVZCS) sof... more This paper presents a comparative analysis of the zero-voltage zero-current switching (ZVZCS) soft switching technique with zero-voltage switching (ZVS) and zero-current switching (ZCS) counterparts. The generalization of the voltage–current crossover or the energy loss factor obtained from simulation of the prototype converter shows that the ZVZCS significantly reduces the losses and helps to improve the efficiency of the converter as compared to the ZVS or the ZCS. On the other hand, it is also found that the soft switching range of operation of the ZVS and the ZCS is largely affected by the maximum switch voltage and switch current, respectively. In contrast, these factors have a negligible effect on the ZVZCS operation which results in an extended range of soft switching operation. Additionally, a detailed PSPICE simulation is performed for selected ZVS, ZCS, and ZVZCS topologies from the recent literature, and the switching losses in the main switches of the converters are meas...
This paper presents an analysis and modeling of the class-E inverter for ZVS/ZVDS execution at an... more This paper presents an analysis and modeling of the class-E inverter for ZVS/ZVDS execution at any duty ratio. The methodology is to determine the input current to the inverter analytically under the assumption that it always remains positive. The latter is ensured by proper selection of the input inductance such that the inverter always operates either in (1) the border condition mode or in (2) the continuous conduction mode regardless of the input ripple. Using this input current and applying the boundary conditions, the required input capacitance for the ZVS/ZVDS execution is determined at a specified input/output voltage, output power and load. The analysis shows that the ZVS/ZVDS can be achieved while the input capacitance is selected appropriately. A comparison between the analytical and simulation results is also formulated involving the proposed and other existing models. The simulation results that are provided at different duty ratios demonstrate that they are in a better ...
This paper presents a comparative analysis of the class E and selected enhanced class E inverters... more This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL). To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter. More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E...
Smart Grid technology as a platform can encompass several advanced technological features across ... more Smart Grid technology as a platform can encompass several advanced technological features across the spectrum of the power system. Smart Grid may introduce an early warning system for structural damage on the surface of large-scale power utility facilities providing crucial information to maintain the safety of the plant. To achieve such a cost-effective structural health monitoring system, a holistic smart inspection implementation framework is required. Using recently available sophisticated inspection technologies, high-resolution images covering the structural condition of large infrastructure can be routinely acquired as a remote monitoring process. Automated analysis of these inspection images can significantly reduce the inspection cost, provide an effective detection mechanism, and shorten reporting time, as a result, reducing overall maintenance costs, and improving safety measures. In this work, we have applied state of art deep learning based inspection image analysis methods for surface damage detection of various renewable energy power plants with a single unified model. We have achieved the state-of-the-art accuracy of 0.79 mean average precision on average even where input images are of varied modalities: from thermal images to visual images, from high-to low-resolution images, and from PV panels to wind turbines. All variations have been tackled with one single deep learning model to detect surface damages. Our results demonstrate the promise of effectively deploying a single trained model to inspect a wide range of energy installations while reducing the monitoring cost significantly. In addition, this work also published the reported dataset comprising four specific image sets for the research community.
Abstract Enhanced sustainability and efficiency are among the prime indicators to achieve in the ... more Abstract Enhanced sustainability and efficiency are among the prime indicators to achieve in the power generation sector of any country. The decline in efficiency might be caused by improper utilization of fuels and increasing entropy in outdated generation units. Reduced efficiency in power generation is particularly detrimental for the sustainability in developing countries, as resources are limited and need to be carefully allocated and maintained. Exergy analysis based on the laws of thermodynamics are currently gaining traction among researchers to study the overall performances of power generation units. Taking Bangladesh as a case study, this work investigates the power generation data for the country since 2009 till 2019 to study the internal energy losses of natural gas, oil, high-speed diesel, coal, and hydro based plants and provides a baseline for investment policy formulation. Our study found that, due to lack of maintenance and proper planning during the initial phases, the overall energy efficiencies among these sectors are relatively low, staying in the range of 34.55%–36.1% while the exergy efficiencies are 35.07%–36.59%. Corresponding exergetic parameters as depletion number, exergy sustainability index, relative irreversibility, lack of production, cumulative exergy loss, waste exergy ratio, and environmental effect factor pointed to similar findings in terms of sustainability as well. Comparing these parameters, it is observed that hydroelectric plants are more sustainable and efficient compared to fossil fuel-based generation units. Cost estimation of fuels and financial losses in the power generation sector are also explored for a better understanding of the return on investment.
Daylight utilization is one of the key areas for energy savings in indoor environments. An import... more Daylight utilization is one of the key areas for energy savings in indoor environments. An important factor often not considered by the existing daylight utilization approaches is the segregation of the floor into task areas and non-task areas. It is also observed that the inherent asymmetry in the daylight penetration pattern in most indoor environments is not given consideration while designing artificial lighting arrangements. Moreover, daily and annual daylight availability is found to have a symmetrical variation pattern, which is a significant factor often overlooked in utilizing daylight. Thus, the energy assessment can be inaccurate, leading to an incorrect or impractical evaluation of energy savings. This research proposes a comprehensive new approach to assess the energy-saving potential of daylight utilization in indoor environments. This new method combines two approaches to overcome the aforementioned issues. (1) The considered area is segmented into task area and non-t...
Journal of Research in Engineering and Applied Sciences, 2018
The main challenge today is to promote the development and commercialization of renewable energy ... more The main challenge today is to promote the development and commercialization of renewable energy sources for widespread adaption. This requires a smooth transition from fossil fuel based generation system to renewable energy supported system. The two main obstacles in this regard are efficiency constraint and cost of renewable sources. Photovoltaic systems are one of the most promising and prominent candidates of emerging renewable sources. Lack of capability of bulk production of energy, system efficiency, availability, reliability, feasibility, sustainability, suitable geographical sites, lifetime, capital cost/investment, commercialization, energy storage, complex manufacturing process and finally cost of energy are the major factors affecting the growth of renewable sources like photovoltaic energy system. Improved performance and cost reduction can increase the use and popularity of the sources.
His research interests are semiconductor A c c e p t e d M a n u s c r i p t device modeling, mat... more His research interests are semiconductor A c c e p t e d M a n u s c r i p t device modeling, material characterization and low power TCAM circuits. He has authored and co-authored several papers published in international conference proceedings and refereed journals. He is a member of IEEE. A c c e p t e d M a n u s c r i p t Review and Comparative Study of I-V Characteristics of Different Memristor Models with Sinusoidal Input Memory-resistor (Memristor) has drawn considerable attention of the researchers in the last decade due to its remarkable properties. After the first concept of memristor, proposed by Leon Chua in 1971, almost no research work was conducted in this field for a long time. However, since the revolutionary discovery of the physical structure of memristor and its model of the HP lab in 2008, a tremendous amount of research work has been going on. Researchers are focusing on improving the models for the analysis of the memristor. Different researchers have come up with their model to improve the existing ones. These models can be linear, nonlinear or exponential. To overcome the boundary problem, many window functions have been proposed. Different models have their explanations of voltage-current relationship and state variable derivatives. This paper presents a detailed review and a comparative study of the existing memristor models based on their I-V characteristic curve. Original experimental I-V curve from the HP lab has been used as the reference for comparison.
Body-channel communication (BCC) is based on the principle of electrical field data transmission ... more Body-channel communication (BCC) is based on the principle of electrical field data transmission attributable to capacitive coupling through the human body. It is gaining importance now a day in the scenario of human centric communication because it truly offers a natural means of interaction with the human body. Traditionally, near field communication (NFC) considers as a magnetic field coupling based on radio frequency identification (RFID) technology. The RFID technology also limits the definition of NFC and thus reduces the scope of a wide range of applications. In recent years BCC, after its first origin in 1995, regain importance with its valuable application in biomedical systems. Primarily, KAIST and Philips research groups demonstrate BCC in the context of biomedical remote patient health monitoring system. BCC transceiver mainly consists of two parts: one is digital baseband and the other is an analog front end (AFE). In this thesis, an analog front end receiver has presented to support the overall BCC. The receiver (Rx) architecture consists of cascaded preamplifier and Schmitt trigger. When the signals are coming from the human body, they are attenuated around 60 dB and gives weak signals in the range of mV. A high gain preamplifier stage needs to amplify these weak signals and make them as strong signals. The preamplifier single stage needs to cascade for the gain requirement. The single stage preamplifier, which is designed with ST65 nm technology, has an open loop gain of 24.01 dB and close loop gain of 19.43 dB. A flipped voltage follower (FVF) topology is used for designing this preamplifier to support the low supply voltage of 1 V because the topology supports low voltage, low noise and also low power consumption. The input-referred noise is 8.69 nV/sqrt(Hz) and the SNR at the input are 73.26 dB. The Schmitt trigger (comparator with hysteresis) is a bistable positive feedback circuit. It builds around two stage OTA with lead frequency compensation. The DC gain for this OTA is 26.94 dB with 1 V supply voltage. The corner analyzes and eye diagram as a performance matrix for the overall receiver are also included in this thesis work. 4 An Input Amplifier for Body-Channel Communication Acknowledgments Firstly I want to thank Almighty Allah for giving me an opportunity to study at the Linköping University and meet some nice people over here.
2014 International Conference on Electrical Engineering and Information & Communication Technology, 2014
ABSTRACT This paper presents a newly cascaded voltage mode tri-state driver circuit for body-coup... more ABSTRACT This paper presents a newly cascaded voltage mode tri-state driver circuit for body-coupled communication (BCC) designed in 65 nm CMOS technology. Each stage of the driver circuit has been resized to meet the requirement of the BCC. It has a driving capability of 6 mA from 1.2 V supply with 10 MHz operating frequency. Different analysis has been performed to get the optimum results for the proposed circuit. The analysis shows cycle to cycle jitter to be less than one and power supply rejection ratio (PSRR) 65 dB, indicating the good emission of supply noise. In addition, the driver circuit does not require a filter to emit the noise because the body acts like a low pass filter.
2014 International Conference on Informatics, Electronics & Vision (ICIEV), 2014
The paper presents performance analysis of an analog front end (AFE) for body-coupled communicati... more The paper presents performance analysis of an analog front end (AFE) for body-coupled communication (BCC) which is based on data transmission via capacitive coupling through the human body. The AFE designs by cascading differential preamplifier and Schmitt trigger. A flipped voltage follower (FVF) topology is used as part of the preamplifier design. The operation frequency of the overall system is mentioned as 10 MHz. The open loop gain is 24.01 dB and the close loop gain is 19.43 dB for this preamplifier. The input referred noise PSD is 8.69 nV/√Hz at 10 MHz. The system runs on a supply voltage of 1 V with implementation being done on 65 nm CMOS technology.
2011 IEEE Symposium on Industrial Electronics and Applications, 2011
Abstract The paper shows the implementation of digital circuit design using ultra-low power logic... more Abstract The paper shows the implementation of digital circuit design using ultra-low power logic components. Fundamentals of Source coupled logic (SCL) gates are used with running at sub-threshold regime with the purpose of achieving low power consumption while ...
Oral condyloma acuminatum or venereal wart is an infectious disease o f the oral mucosa caused by... more Oral condyloma acuminatum or venereal wart is an infectious disease o f the oral mucosa caused by a virus similar or identical to that causing Verrucae vulgaris and plantaris. I t consists of papillomatous projections with marked parakeratosis or keratosis and acanthotic epithelial downgrowlhs. Vacuolated cells are often a feature o f the stratum spinosum. Criteria for the differential diagnosis and surgical management of this condition are presented.
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Papers by Hasan Maruf