Majid Fouladian - Academia.edu (original) (raw)

Papers by Majid Fouladian

Research paper thumbnail of An optoelectronic Coupler based on graphene patterns and SU-8 photoresist

Research paper thumbnail of Survey of Cloud Government Services in Different Countries, Case Study (Australia-UK and US)

Research paper thumbnail of A 5-GHZ VCO for WLAN applications

A fully monolithic 5 GHz CMOS LC-VCO, designed in a 0.18 μm 1P6M CMOS technology, is presented in... more A fully monolithic 5 GHz CMOS LC-VCO, designed in a 0.18 μm 1P6M CMOS technology, is presented in this paper. The tuning range of the VCO is from 4.1 GHz to 5.24 GHz, about 24%. The measured phase noise at 5-GHz is -115.8 dBc/Hz at 1 MHz offset from the carrier. It meets the requirements for IEEE 802.11a WLAN standard. The current dissipation of the VCO is 2 mA from the 1.8 V power supply.

Research paper thumbnail of Zero forcing based sphere decoder for generalized spatial modulation systems

Etri Journal, Jan 21, 2019

Research paper thumbnail of Counteracting Threshold-Voltage Drift in Ion-Selective Field Effect Transistors (ISFETs) Using Threshold-Setting Ion Implantation

IEEE Journal of the Electron Devices Society, 2018

Ion-selective field effect transistors (ISFETs) exhibit instability, commonly known as drift, in ... more Ion-selective field effect transistors (ISFETs) exhibit instability, commonly known as drift, in the form of a slow, monotonic, temporal increase in the threshold voltage of the device. A method for counteracting instability inspired by a physical model for threshold voltage drift in pH-sensitive ISFETs is presented. This method involves adjusting the charge density at the insulator-semiconductor interface using threshold-setting ion implantation such that the net charge induced in the semiconductor at the operating point of the device is minimized. The proposed method is analytically validated based on characterization and modeling of drift in an Al 2 O 3-gate pH-sensitive ISFET. Counteraction of ISFET drift by ion implantation is also demonstrated using TCAD simulations. The optimum donor-type implant dose of 3.25×10 11 cm −2 determined based on ATLAS simulations is in good agreement with the corresponding dose of 6.58 × 10 11 cm −2 obtained analytically.

Research paper thumbnail of Multi layers THz duplexer based on combined graphene patterns

Solid State Communications, Feb 1, 2023

Research paper thumbnail of Using deep learning methods for discovering associations between drugs and side effects based on topic modeling in social network

Social Network Analysis and Mining, May 24, 2020

The relationship between drug and its side effects has been delineated in two websites, namely Si... more The relationship between drug and its side effects has been delineated in two websites, namely Sider and WebMD. The aim of the present paper is to find the relationship between drug and its side effects as reported by typical users of a website called Ask a patient , and to compare these reports with the side effects in reference sites. In addition, the typical users’ comments on highly-commented drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) within last decade were analyzed. The reason for such investigation is the fact that typical users’ comments and their tendencies can be considered as an important factor in determining the best drugs in improving them or decreasing their risk dangerous. Typical users’ comments on drugs’ side effects were gathered from the website Ask a patient. Then, the data on drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) were classified according to deep learning model. At first using the model, the three issues, namely drug, its side effect and the cause of the side effect, were explained. Afterward, using topic modeling, the main topics of side effects for each group of drugs were identified. Finally, using the websites of Sider and WebMD in which the side effects of drugs are reported, the side effects of the three classes of drugs were retrieved. The goal of the present research was to analyze typical users’ comments reported on the website called Ask a patient , and to compare these comments with the reports about the side effects of drugs from important sites. Our model demonstrates its ability to accurately describe and label side effects in a temporal text corpus. By taking full advantage of deep learning classifiers, the used methods in text mining is shown to be accurate and effective for discovering association between drugs and side effects. Moreover, through combining with modular classifier in addition to topic modeling, this model has the capability to immediately locate information in reference sites to recognize the side effect of new drugs. In fact, due to the unbiased nature of typical users’ comments, these comments can be a reliable indicator for drug producer companies to reduce the side effects of drugs.

Research paper thumbnail of Two directional <scp>THz</scp> wave duplexer and filter based on graphene disks and rings

International Journal of Numerical Modelling-electronic Networks Devices and Fields, Jan 2, 2023

Coating both sides of a dielectric spacer with graphene patterns, leads to a tunable meta surface... more Coating both sides of a dielectric spacer with graphene patterns, leads to a tunable meta surface which acts as a THz duplexer. Two separate channels, reflection and transmission are considered as outputs ports while the aim is to minimize absorption ration. The presented structure consists of periodic arrays of graphene patterns on both sides of silicon dioxide as substrate. Moreover, the patterns include disks and rings are biased differently compared to conventional patterns which makes it possible to achieve tunable behaviors versus external bias. utilizing equivalent circuit models (ECM) for graphene patterns and dielectric, the whole structure is modeled by passive RLC branches. According to the simulation outputs, the presented structure can transmit and reflect incident THz waves at desired frequencies in 0.1 THz to 30 THz which makes it an ideal candidate for manipulating THz waves in terms of transmission and reflection. The THz duplexer can transmit and reflect incident waves at 1–3.3 THz as wide‐band and 1.05 THz as narrow‐band operation. Such a tunable device is in great demand for indoor communications, security, less harmful medical imaging and space related researches.

Research paper thumbnail of An ultra-wideband low noise amplifier with cascaded flipped-active inductor for cognitive radio applications

Research paper thumbnail of Improving Radar Absorbing Capability of Polystyrene Nanocomposites: Preparation and Investigation of Microwave Absorbing Properties

Journal of Nanostructures, Apr 1, 2020

Microwave absorbing materials are usually designed to solve protection against electromagnetic in... more Microwave absorbing materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this research polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized. The novelty of this work is comparing of three various nanostructures: non-metallic conductive graphene oxide, magnetic Fe 3 O 4 and semiconductor zinc oxide were used as additive. The effect of different fillers loading and homogenizer speed on the reflection loss (RL) amount and electromagnetic wave absorption was investigated. In order to investigate particle size and morphology of the nanostructures the scanning electron microscopy (SEM) was used. The frequency range of 5-8 GHz was employed in the investigation of electromagnetic wave absorption properties of nanocomposites using a vector network analyzer and eventually their absorption properties were analyzed and compared. The results indicate that graphene oxide has substantial effect on absorption in compare with the other nanocomposite samples. Increase of homogenizer speed led to a dispersion improvement of nanostructures and absorption. Therefore, the broadening of the microwave absorption band-width is attributed to the suitable dispersion of nanostructures in polymeric matrix.

Research paper thumbnail of Improving Throughput and Delay by Signaling Modification in Integrated 802.11 and 3G Heterogeneous Wireless Network

International Journal of Advanced Computer Science and Applications, 2016

Current trends show that UMTS network and WLAN will co-exist and work together to support more us... more Current trends show that UMTS network and WLAN will co-exist and work together to support more users with higher data rate services over a wider area. However, this integration invokes many challenges such as mobility management and handoff decision making. Vertical handoff is switching process between heterogeneous wireless networks in a 3G/WLAN network. Vertical handoffs often fail due to the abrupt degrade of the WLAN signal strength. In this paper, proposed a new vertical handoff method for to decrease the number of signaling and registration processes, to examine the Special conditions such as WLAN black holes and to eliminate disconnecting effects. By estimating user locations related to WLAN position, interface on-times will be reduced which makes the power consuming of the system decreased. To indicate the efficiency of proposed approach the performance and the delay results are simulated.

Research paper thumbnail of An ultra-wideband low noise amplifier with cascaded flipped-active inductor for cognitive radio applications

Research paper thumbnail of Two directional THz wave duplexer and filter based on graphene disks and rings

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

Research paper thumbnail of Multi layers THz duplexer based on combined graphene patterns

Solid State Communications

Research paper thumbnail of Survey of Cloud Government Services in Different Countries, Case Study (Australia-UK and US)

Research paper thumbnail of A wideband tunable microwave graphene-based absorber and duplexer

Solid State Communications

Research paper thumbnail of Branch, Islamic Azad University

Abstract—Current trends show that UMTS network and WLAN will co-exist and work together to suppor... more Abstract—Current trends show that UMTS network and WLAN will co-exist and work together to support more users with higher data rate services over a wider area. However, this integration invokes many challenges such as mobility management and handoff decision making. Vertical handoff is switching process between heterogeneous wireless networks in a 3G/WLAN network. Vertical handoffs often fail due to the abrupt degrade of the WLAN signal strength. In this paper, proposed a new vertical handoff method for to decrease the number of signaling and registration processes, to examine the Special conditions such as WLAN black holes and to eliminate disconnecting effects. By estimating user locations related to WLAN position, interface on-times will be reduced which makes the power consuming of the system decreased. To indicate the efficiency of proposed approach the performance and the delay results are simulated. Keywords—Registration; WLAN; 3G network; Vertical handover

Research paper thumbnail of Using deep learning methods for discovering associations between drugs and side effects based on topic modeling in social network

Social Network Analysis and Mining, 2020

The relationship between drug and its side effects has been delineated in two websites, namely Si... more The relationship between drug and its side effects has been delineated in two websites, namely Sider and WebMD. The aim of the present paper is to find the relationship between drug and its side effects as reported by typical users of a website called Ask a patient , and to compare these reports with the side effects in reference sites. In addition, the typical users’ comments on highly-commented drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) within last decade were analyzed. The reason for such investigation is the fact that typical users’ comments and their tendencies can be considered as an important factor in determining the best drugs in improving them or decreasing their risk dangerous. Typical users’ comments on drugs’ side effects were gathered from the website Ask a patient. Then, the data on drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) were classified according to deep learning model. At first using the model, the three issues, namely ...

Research paper thumbnail of Improving Radar Absorbing Capability of Polystyrene Nanocomposites: Preparation and Investigation of Microwave Absorbing Properties

Microwave absorbing materials are usually designed to solve protection against electromagnetic in... more Microwave absorbing materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this research polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized. The novelty of this work is comparing of three various nanostructures: non-metallic conductive graphene oxide, magnetic Fe3O4 and semi-conductor zinc oxide were used as additive. The effect of different fillers loading and homogenizer speed on the reflection loss (RL) amount and electromagnetic wave absorption was investigated. In order to investigate particle size and morphology of the nanostructures the scanning electron microscopy (SEM) was used. The frequency range of 5-8 GHz was employed in the investigation of electromagnetic wave absorption properties of nanocomposites using a vector network analyzer and eventually their absorption properties were analyzed and compared. The results indica...

Research paper thumbnail of Optimal design of a lightweight and thin radar absorbing nanocomposite

Recently, attention to polymeric nanocomposites has gained a great extent as they present new opp... more Recently, attention to polymeric nanocomposites has gained a great extent as they present new opportunities to provide superior properties in microwave absorbing materials. In this study polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized and employed as microwave absorbing materials. The mentioned materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this study the performance of three various polystyrene (PS) nanocomposites containing: semi-conductor zinc oxide, non-metallic conductive graphene oxide and magnetic Fe3O4 were compared. The fillers type was selected as variable parameter and its influence on the electromagnetic wave absorption and reflection loss (RL) amount was investigated. The scanning electron microscopy (SEM) was used in morphological and particle size study of the nanocomposites. The electromagnetic wave absorpt...

Research paper thumbnail of An optoelectronic Coupler based on graphene patterns and SU-8 photoresist

Research paper thumbnail of Survey of Cloud Government Services in Different Countries, Case Study (Australia-UK and US)

Research paper thumbnail of A 5-GHZ VCO for WLAN applications

A fully monolithic 5 GHz CMOS LC-VCO, designed in a 0.18 μm 1P6M CMOS technology, is presented in... more A fully monolithic 5 GHz CMOS LC-VCO, designed in a 0.18 μm 1P6M CMOS technology, is presented in this paper. The tuning range of the VCO is from 4.1 GHz to 5.24 GHz, about 24%. The measured phase noise at 5-GHz is -115.8 dBc/Hz at 1 MHz offset from the carrier. It meets the requirements for IEEE 802.11a WLAN standard. The current dissipation of the VCO is 2 mA from the 1.8 V power supply.

Research paper thumbnail of Zero forcing based sphere decoder for generalized spatial modulation systems

Etri Journal, Jan 21, 2019

Research paper thumbnail of Counteracting Threshold-Voltage Drift in Ion-Selective Field Effect Transistors (ISFETs) Using Threshold-Setting Ion Implantation

IEEE Journal of the Electron Devices Society, 2018

Ion-selective field effect transistors (ISFETs) exhibit instability, commonly known as drift, in ... more Ion-selective field effect transistors (ISFETs) exhibit instability, commonly known as drift, in the form of a slow, monotonic, temporal increase in the threshold voltage of the device. A method for counteracting instability inspired by a physical model for threshold voltage drift in pH-sensitive ISFETs is presented. This method involves adjusting the charge density at the insulator-semiconductor interface using threshold-setting ion implantation such that the net charge induced in the semiconductor at the operating point of the device is minimized. The proposed method is analytically validated based on characterization and modeling of drift in an Al 2 O 3-gate pH-sensitive ISFET. Counteraction of ISFET drift by ion implantation is also demonstrated using TCAD simulations. The optimum donor-type implant dose of 3.25×10 11 cm −2 determined based on ATLAS simulations is in good agreement with the corresponding dose of 6.58 × 10 11 cm −2 obtained analytically.

Research paper thumbnail of Multi layers THz duplexer based on combined graphene patterns

Solid State Communications, Feb 1, 2023

Research paper thumbnail of Using deep learning methods for discovering associations between drugs and side effects based on topic modeling in social network

Social Network Analysis and Mining, May 24, 2020

The relationship between drug and its side effects has been delineated in two websites, namely Si... more The relationship between drug and its side effects has been delineated in two websites, namely Sider and WebMD. The aim of the present paper is to find the relationship between drug and its side effects as reported by typical users of a website called Ask a patient , and to compare these reports with the side effects in reference sites. In addition, the typical users’ comments on highly-commented drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) within last decade were analyzed. The reason for such investigation is the fact that typical users’ comments and their tendencies can be considered as an important factor in determining the best drugs in improving them or decreasing their risk dangerous. Typical users’ comments on drugs’ side effects were gathered from the website Ask a patient. Then, the data on drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) were classified according to deep learning model. At first using the model, the three issues, namely drug, its side effect and the cause of the side effect, were explained. Afterward, using topic modeling, the main topics of side effects for each group of drugs were identified. Finally, using the websites of Sider and WebMD in which the side effects of drugs are reported, the side effects of the three classes of drugs were retrieved. The goal of the present research was to analyze typical users’ comments reported on the website called Ask a patient , and to compare these comments with the reports about the side effects of drugs from important sites. Our model demonstrates its ability to accurately describe and label side effects in a temporal text corpus. By taking full advantage of deep learning classifiers, the used methods in text mining is shown to be accurate and effective for discovering association between drugs and side effects. Moreover, through combining with modular classifier in addition to topic modeling, this model has the capability to immediately locate information in reference sites to recognize the side effect of new drugs. In fact, due to the unbiased nature of typical users’ comments, these comments can be a reliable indicator for drug producer companies to reduce the side effects of drugs.

Research paper thumbnail of Two directional <scp>THz</scp> wave duplexer and filter based on graphene disks and rings

International Journal of Numerical Modelling-electronic Networks Devices and Fields, Jan 2, 2023

Coating both sides of a dielectric spacer with graphene patterns, leads to a tunable meta surface... more Coating both sides of a dielectric spacer with graphene patterns, leads to a tunable meta surface which acts as a THz duplexer. Two separate channels, reflection and transmission are considered as outputs ports while the aim is to minimize absorption ration. The presented structure consists of periodic arrays of graphene patterns on both sides of silicon dioxide as substrate. Moreover, the patterns include disks and rings are biased differently compared to conventional patterns which makes it possible to achieve tunable behaviors versus external bias. utilizing equivalent circuit models (ECM) for graphene patterns and dielectric, the whole structure is modeled by passive RLC branches. According to the simulation outputs, the presented structure can transmit and reflect incident THz waves at desired frequencies in 0.1 THz to 30 THz which makes it an ideal candidate for manipulating THz waves in terms of transmission and reflection. The THz duplexer can transmit and reflect incident waves at 1–3.3 THz as wide‐band and 1.05 THz as narrow‐band operation. Such a tunable device is in great demand for indoor communications, security, less harmful medical imaging and space related researches.

Research paper thumbnail of An ultra-wideband low noise amplifier with cascaded flipped-active inductor for cognitive radio applications

Research paper thumbnail of Improving Radar Absorbing Capability of Polystyrene Nanocomposites: Preparation and Investigation of Microwave Absorbing Properties

Journal of Nanostructures, Apr 1, 2020

Microwave absorbing materials are usually designed to solve protection against electromagnetic in... more Microwave absorbing materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this research polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized. The novelty of this work is comparing of three various nanostructures: non-metallic conductive graphene oxide, magnetic Fe 3 O 4 and semiconductor zinc oxide were used as additive. The effect of different fillers loading and homogenizer speed on the reflection loss (RL) amount and electromagnetic wave absorption was investigated. In order to investigate particle size and morphology of the nanostructures the scanning electron microscopy (SEM) was used. The frequency range of 5-8 GHz was employed in the investigation of electromagnetic wave absorption properties of nanocomposites using a vector network analyzer and eventually their absorption properties were analyzed and compared. The results indicate that graphene oxide has substantial effect on absorption in compare with the other nanocomposite samples. Increase of homogenizer speed led to a dispersion improvement of nanostructures and absorption. Therefore, the broadening of the microwave absorption band-width is attributed to the suitable dispersion of nanostructures in polymeric matrix.

Research paper thumbnail of Improving Throughput and Delay by Signaling Modification in Integrated 802.11 and 3G Heterogeneous Wireless Network

International Journal of Advanced Computer Science and Applications, 2016

Current trends show that UMTS network and WLAN will co-exist and work together to support more us... more Current trends show that UMTS network and WLAN will co-exist and work together to support more users with higher data rate services over a wider area. However, this integration invokes many challenges such as mobility management and handoff decision making. Vertical handoff is switching process between heterogeneous wireless networks in a 3G/WLAN network. Vertical handoffs often fail due to the abrupt degrade of the WLAN signal strength. In this paper, proposed a new vertical handoff method for to decrease the number of signaling and registration processes, to examine the Special conditions such as WLAN black holes and to eliminate disconnecting effects. By estimating user locations related to WLAN position, interface on-times will be reduced which makes the power consuming of the system decreased. To indicate the efficiency of proposed approach the performance and the delay results are simulated.

Research paper thumbnail of An ultra-wideband low noise amplifier with cascaded flipped-active inductor for cognitive radio applications

Research paper thumbnail of Two directional THz wave duplexer and filter based on graphene disks and rings

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

Research paper thumbnail of Multi layers THz duplexer based on combined graphene patterns

Solid State Communications

Research paper thumbnail of Survey of Cloud Government Services in Different Countries, Case Study (Australia-UK and US)

Research paper thumbnail of A wideband tunable microwave graphene-based absorber and duplexer

Solid State Communications

Research paper thumbnail of Branch, Islamic Azad University

Abstract—Current trends show that UMTS network and WLAN will co-exist and work together to suppor... more Abstract—Current trends show that UMTS network and WLAN will co-exist and work together to support more users with higher data rate services over a wider area. However, this integration invokes many challenges such as mobility management and handoff decision making. Vertical handoff is switching process between heterogeneous wireless networks in a 3G/WLAN network. Vertical handoffs often fail due to the abrupt degrade of the WLAN signal strength. In this paper, proposed a new vertical handoff method for to decrease the number of signaling and registration processes, to examine the Special conditions such as WLAN black holes and to eliminate disconnecting effects. By estimating user locations related to WLAN position, interface on-times will be reduced which makes the power consuming of the system decreased. To indicate the efficiency of proposed approach the performance and the delay results are simulated. Keywords—Registration; WLAN; 3G network; Vertical handover

Research paper thumbnail of Using deep learning methods for discovering associations between drugs and side effects based on topic modeling in social network

Social Network Analysis and Mining, 2020

The relationship between drug and its side effects has been delineated in two websites, namely Si... more The relationship between drug and its side effects has been delineated in two websites, namely Sider and WebMD. The aim of the present paper is to find the relationship between drug and its side effects as reported by typical users of a website called Ask a patient , and to compare these reports with the side effects in reference sites. In addition, the typical users’ comments on highly-commented drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) within last decade were analyzed. The reason for such investigation is the fact that typical users’ comments and their tendencies can be considered as an important factor in determining the best drugs in improving them or decreasing their risk dangerous. Typical users’ comments on drugs’ side effects were gathered from the website Ask a patient. Then, the data on drugs (neurotic drugs, anti-pregnancy drugs and digestion drugs) were classified according to deep learning model. At first using the model, the three issues, namely ...

Research paper thumbnail of Improving Radar Absorbing Capability of Polystyrene Nanocomposites: Preparation and Investigation of Microwave Absorbing Properties

Microwave absorbing materials are usually designed to solve protection against electromagnetic in... more Microwave absorbing materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this research polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized. The novelty of this work is comparing of three various nanostructures: non-metallic conductive graphene oxide, magnetic Fe3O4 and semi-conductor zinc oxide were used as additive. The effect of different fillers loading and homogenizer speed on the reflection loss (RL) amount and electromagnetic wave absorption was investigated. In order to investigate particle size and morphology of the nanostructures the scanning electron microscopy (SEM) was used. The frequency range of 5-8 GHz was employed in the investigation of electromagnetic wave absorption properties of nanocomposites using a vector network analyzer and eventually their absorption properties were analyzed and compared. The results indica...

Research paper thumbnail of Optimal design of a lightweight and thin radar absorbing nanocomposite

Recently, attention to polymeric nanocomposites has gained a great extent as they present new opp... more Recently, attention to polymeric nanocomposites has gained a great extent as they present new opportunities to provide superior properties in microwave absorbing materials. In this study polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized and employed as microwave absorbing materials. The mentioned materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this study the performance of three various polystyrene (PS) nanocomposites containing: semi-conductor zinc oxide, non-metallic conductive graphene oxide and magnetic Fe3O4 were compared. The fillers type was selected as variable parameter and its influence on the electromagnetic wave absorption and reflection loss (RL) amount was investigated. The scanning electron microscopy (SEM) was used in morphological and particle size study of the nanocomposites. The electromagnetic wave absorpt...