The International Journal of Health Planning and Management
In responding to the COVID‐19 pandemic, each country is presented with both opportunities and cha... more In responding to the COVID‐19 pandemic, each country is presented with both opportunities and challenges, some unique and some shared with the global community. It is important to not only recognize, but to embrace them as drivers of the public to the current pandemic success. In this commentary, we discuss the opportunities and challenges that may affect ongoing public health programming in Australia within the current context of epidemiology. COVID‐19 within Australia has to date been effectively suppressed through the implementation of nationally coordinated, in which the state delivered public policy, guidelines and practice, and successful establishment of a comprehensive testing, contact tracing, patient isolation and contact quarantine regime combined with national and state social distancing, hygiene etiquette and movement restrictions. However, despite its success to date great challenges lay ahead for future public health policy with the threat of a second wave, or more li...
In this paper, we study the problem of joint inband backhauling and interference mitigation in 5G... more In this paper, we study the problem of joint inband backhauling and interference mitigation in 5G heterogeneous networks (HetNets) in which a massive multiple-input multipleoutput (MIMO) macro cell base station equipped with a large number of antennas, overlaid with self-backhauled small cells is assumed. This problem is cast as a network utility maximization subject to wireless backhaul constraints. Due to the non-tractability of the problem, we first resort to random matrix theory to get a closed-form expression of the achievable rate and transmit power in the asymptotic regime, i.e., as the number of antennas and users grows large. Subsequently, leveraging the framework of stochastic optimization, the problem is decoupled into dynamic scheduling of macro cell users and backhaul provisioning of small cells as a function of interference and backhaul links. Via simulations, we evaluate the performance gains of our proposed framework under different network architectures and low/high...
With the unprecedented growth in mobile data traffic and network densification, the emerging fift... more With the unprecedented growth in mobile data traffic and network densification, the emerging fifth-generation (5G) wireless network warrants a paradigm shift with respect to system design and technological enablers. In this regard, the prime motivation of this thesis is to propose an integrated access-backhaul (IAB) framework to dynamically schedule users, while efficiently providing a wireless backhaul to dense small cells and mitigating interference. In addition, joint resource allocation and interference mitigation solutions are proposed for two-hop and multi-hop self-backhauled millimeter wave (mmWave) networks. The first contribution of this thesis focuses on a multiuser two-hop relay cellular system in which a massive antenna array enabled macro base station (BS) simultaneously provides high beamforming gains to outdoor users, and wireless backhauling to outdoor small cells. Moreover, a hierarchical interference mitigation scheme is applied to efficiently mitigate cross-tier and cotier interference. In the second contribution, a multi-hop self-backhauled mmWave communication scenario is studied whereby a joint multi-hop multi-path selection and rate allocation framework is proposed to enable Gbps data rates with reliable communications. Using reinforcement learning techniques, a dynamic and efficient rerouting solution is proposed to cope with blockage and latency constraints. Finally, a risk-sensitive learning solution is leveraged to provide high-reliability and low-latency communications. In summary, the dissertation analyses key trade-offs between (i) capacity and latency, (ii) reliability and network density. Extensive simulation results were carried out to verify the performance gains of the proposed algorithms compared to several baselines and for different network settings. Key findings show significant improvements in terms of higher data rates, lower latency, and reliable communications with some trade-offs.
For emerging applications such as wireless video cameras, wireless low-power surveillance network... more For emerging applications such as wireless video cameras, wireless low-power surveillance networks, and disposable video cameras for medical applications. DVC is useful and maybe the best choice. Since the primary objective of DVC is low-complexity video encoding, the bulk of computation is shifted (transmitted) to the decoder, as opposed to a low-complexity decoder in conventional video compression standards such as H.264 and MPEG. Besides the low bit rate, the transmission has to be very secure also. That means the complexity of the used keys should be rather high and the keyspace has to be large to provide enough individual keys for a large wireless sensor network.
Global Journal of Engineering and Technology Advances, 2021
The problem of heating slab is a very important and highly applicable problem in the material pro... more The problem of heating slab is a very important and highly applicable problem in the material processing industry. This paper presents a method to design a PID controller according to the characteristic polynomial method to control the temperature for slab based on the transfer function model. The parameters of the PID controller are determined based on the parameters of the slab model, the heating furnace model, the converter model. The simulation results show that: the PID controller is capable of controlling the temperature of the slab to the desired temperature without over-adjusting.
Millimeter Wave (mmWave) systems are considered as one of the key technologies in future wireless... more Millimeter Wave (mmWave) systems are considered as one of the key technologies in future wireless systems due to the abundant spectrum resources in mmWave band. With the aim of achieving the capacity requirements in vehicular networks, large antenna arrays can be deployed at both the road side units (RSUs) side and the vehicles side. However, dynamic blockage caused by mobile obstacles in mmWave bands may hinder the system reliability. In this work, we study the temporal effects of dynamic blockage in vehicular networks and propose a deep reinforcement learning framework to overcome dynamic blockage. By dynamically adjusting blockage detection parameters and making intelligent handover decisions according to the observed states, system reliability can be significantly improved. Simulation results based on ray-tracing channel data show that the proposed scheme reduces the violation probability by 28.9% over conventional schemes.
With the emergence of data markets, data have become an asset that is used as part of transaction... more With the emergence of data markets, data have become an asset that is used as part of transactions. Current data markets rely on trusted third parties to manage the data, creating single points of failure with possibly disastrous consequences on data privacy and security. The lack of technical solutions to enforce strong privacy and security guarantees leaves the data markets' stakeholders (e.g., buyers and sellers of data) vulnerable when they transact data. Smart Contracts and Multi-Party Computation represent examples of emerging technologies that have the potential to guarantee the desired levels of data privacy and security. In this paper, we propose an architecture for data markets based on Smart Contracts and Multi-Party Computation and present a proof of concept prototype developed to demonstrate the feasibility of the proposed architecture.
IEEE Transactions on Wireless Communications, 2017
We study the problem of joint load balancing (user association and user scheduling) and interfere... more We study the problem of joint load balancing (user association and user scheduling) and interference management (beamforming design and power allocation) in heterogeneous networks (HetNets) in which massive multiple-input multipleoutput (MIMO) macro cell base station (BS) equipped with a large number of antennas, overlaid with wireless self-backhauled small cells (SCs) are assumed. Self-backhauled SC BSs with fullduplex communication employing regular antenna arrays serve both macro users and SC users by using the wireless backhaul from macro BS in the same frequency band. We formulate the joint load balancing and interference mitigation problem as a network utility maximization subject to wireless backhaul constraints. Subsequently, leveraging the framework of stochastic optimization, the problem is decoupled into dynamic scheduling of macro cell users, backhaul provisioning of SCs, and offloading macro cell users to SCs as a function of interference and backhaul links. Via numerical results, we show the performance gains of our proposed framework under the impact of SCs density, number of BS antennas, and transmit power levels at low and high frequency bands. It is shown that our proposed approach achieves a 5.6× gain in terms of cell-edge performance as compared to the closed-access baseline in ultra-dense networks with 350 SC BSs per km 2 .
Ultra-reliability and low-latency are two key components in 5G networks. In this letter, we inves... more Ultra-reliability and low-latency are two key components in 5G networks. In this letter, we investigate the problem of ultra-reliable and low-latency communication (URLLC) in millimeter wave (mmWave)-enabled massive multiple-input multipleoutput (MIMO) networks. The problem is cast as a network utility maximization subject to probabilistic latency and reliability constraints. To solve this problem, we resort to the Lyapunov technique whereby a utility-delay control approach is proposed, which adapts to channel variations and queue dynamics. Numerical results demonstrate that our proposed approach ensures reliable communication with a guaranteed probability of 99.99%, and reduces latency by 28.41% and 77.11% as compared to baselines with and without probabilistic latency constraints, respectively. Index Terms-5G, massive MIMO, mmWave, ultra-reliable low latency communications (URLLC). I. INTRODUCTION C URRENTLY, millimeter wave (mmWave) and massive multiple-input multiple-output (MIMO) techniques are investigated to provide reliable communication with an overthe-air latency of few milliseconds and extreme throughput [1]. While massive MIMO with large degrees of freedom provides high energy and spectral efficiency [2], mmWave frequency bands provide large bandwidth [3]. In addition, due to the short wavelength of mmWaves, large antenna array can be packed into highly directional beamforming, which makes massive MIMO practically feasible [4]. Thus far, most of existing works on mmWave-enabled massive MIMO systems focus mainly on providing capacity improvement [4], while latency and reliability are not addressed. Although latency and reliability are applicable to many scenarios (e.g. mission-critical applications), in this work, we are interested in the integration of mmWave communication and massive MIMO techniques, which holds the promise of providing great enhancements of the overall system performance [1], [2], [4]. Specifically, this letter is concerned with addressing the fundamental question in mmWave-enabled massive MIMO systems: "how to simultaneously provide order of magnitude capacity improvements and latency reduction?"
Model order reduction is a research direction which has provided interest to many scientists rece... more Model order reduction is a research direction which has provided interest to many scientists recently. A large number of order reduction algorithms have been introduced in many different approaches among which retaining the important poles of the original system in the reduced root system is a dominant approach with many advantages. This paper presents a new model in order reduction algorithm for both stable and unstable systems, based on the idea of keeping the dominant poles of the original system in the order reduction process. This algorithm transforms matrix A of the higher-order original system to upper-triangle matrix on which the poles are arranged basically on H -and 2 H-mixed dominant index on the main diagonal of the upper-triangle matrix so that error becomes small and the dominant poles are preserved. The illustration shows the correctness of the model order algorithm.
Heterogeneous hetworks (HetNets) have been introduced as an emerging technology in order to meet ... more Heterogeneous hetworks (HetNets) have been introduced as an emerging technology in order to meet the increasing demand for mobile data. HetNets are a combination of multi-layer networks such as macrocells and small cells. In such networks, users may suffer significant cross-layer interference. To manage this interference, the 3rd Generation Partnership Project (3GPP) has introduced enhanced Inter-Cell Interference Coordination (eICIC) techniques. Almost Blank SubFrame (ABSF) is one of the time-domain techniques used in eICIC solutions. We propose a dynamically optimal Signal-to-Interference-and-Noise Ratio (SINR)-based ABSF framework to ensure macro user performance while maintaining small user performance. We also study cooperative mechanisms to help small cells collaborate efficiently in order to reduce mutual interference. Simulations show that our proposed scheme achieves good performance and outperforms the existing ABSF frameworks.
Rhamnolipid is a biosurfactant produced by several Pseudomonas species, and can wet hydrophobic s... more Rhamnolipid is a biosurfactant produced by several Pseudomonas species, and can wet hydrophobic soils by lowering the cohesive and/or adhesive surface tension. Because of its biodegradability, rhamnolipid is believed to have minimal adverse impact on the soil and groundwater after usage. Applications of rhamnolipid to improve irrigation in agricultural soils thus have obvious advantages over other chemical wetting agents, especially under drought conditions. Due to global warming, soil amendment with biochar has been commonly practiced in agricultural soils to increase the soil water-holding capacity. As such, rhamnolipid transport in biochar-amended agricultural soils needs to be characterized. In this research, we found that rhamnolipid transport in biochar-amended agricultural soils was hindered by retardation (equilibrium adsorption) and deposition (kinetic adsorption), which was well represented by the advection-dispersion equation based on a local equilibrium assumption. A linear equilibrium adsorption was assumed in the advection-dispersion equation simulation, which was proved to be acceptable by studying the breakthrough curves. Both rhamnolipid equilibrium adsorption and kinetic adsorption increased with the increase of the biochar content in the agricultural soil.
Large particle sizes having a strong light scattering lead to a significantly decreased surface a... more Large particle sizes having a strong light scattering lead to a significantly decreased surface area and small particle sizes having large surface area lack light-scattering effect. How to combine large and small particle sizes together is an interesting work for achieving higher solar efficiency. In this work, we investigate the solar performance influence of the dye-sensitized solar cells (DSSCs) by the multiple titanium oxide (TiO2) layers with different particle sizes. It was found that the optimal TiO2thickness depends on the particle sizes of TiO2layers for achieving the maximum efficiency. The solar efficiency of DSSCs prepared by triple TiO2layers with different particle sizes is higher than that by double TiO2layers for the same TiO2thickness. The choice of particle size in the bottom layer is more important than that in the top layer for achieving higher solar efficiency. The choice of the particle sizes in the middle layer depends on the particle sizes in the bottom and t...
Localization of a needle tip is important for biopsy examinations in clinics. However, the needle... more Localization of a needle tip is important for biopsy examinations in clinics. However, the needle tip is sometimes difficult to discern under the guidance of sonography due to its poor visibility. A mini actuator that radiates a low-intensity ultrasound wave was manufactured using micro-electro-mechanical system (MEMS) technology. Interference between the radiated and diagnostic ultrasound pulses was observed as bright lines in the B-mode ultrasound image, from which the mini actuator could be recognized with ease. Because the distance between the mini actuator and the needle tip is fixed, the needle tip can be determined despite its inconsistent appearance in the sonography. Both gel phantom and ex vivo tissue evaluation showed that the needle tip can be determined reliably utilizing the acoustic interference pattern.
Bacterial transport in the subsurface is controlled by their interactions with the surrounding en... more Bacterial transport in the subsurface is controlled by their interactions with the surrounding environment, which are determined by the surface properties of the geological formation and bacterial surfaces. In this research, surface thermodynamic properties of Escherichia coli and the geological formation of aluminosilica clays were characterized based on contact angle measurements, which were utilized to quantify the distance-dependent interactions between E. coli and the geological formation according to the traditional and extended Derjaguin, Landau, Verwey and Overbeek (DLVO) theory. E. coli attachment to aluminosilica clays was evaluated in laboratory columns under saturated and steady-state flow conditions. E. coli deposition coefficient and desorption coefficient were simulated using convection-dispersion transport models against E. coli breakthrough curves, which were then linked to interactions between E. coli and the geological formation. It was discovered that E. coli deposition was controlled by the long-ranged electrostatic interaction and E. coli desorption was attributed to the short-ranged Lifshitz-van der Waals and Lewis acid-base interactions. E. coli transport in three layers of different alumino-silica clays was further examined and the breakthrough curve was simulated using E. coli deposition coefficient and desorption coefficient obtained from their individual column experiments. The well-fitted simulation confirmed that E. coli transport observations were interaction-dependent phenomena between E. coli and the geological formation.
2013 IEEE 8th Conference on Industrial Electronics and Applications (ICIEA), 2013
Development of balanced control for the twowheeled mobile robot has attracted many researchers in... more Development of balanced control for the twowheeled mobile robot has attracted many researchers in the recent years. One difficulty for this control problem is that the controlling object is always unstable and is affected by interferences. To solve this problem, the authors of the previous research offer use robust control algorithm H ∞. However, the two-wheeled mobile robot balancing controller under H ∞ robust control algorithms often has high order, complexity which will be significant when programming for controller and impact on quality in the process of factual control. This paper has proposed a new algorithm for reducing model orders in general and applying to reduce orders of controller in balance control of twowheeled robot in particular. Proposed order reduction model algorithm can be applied in other fields such as digital signal processing Keywords-the two-wheeled mobile robot, robust control algorithms, reducing model order, balanced control I.
The International Journal of Health Planning and Management
In responding to the COVID‐19 pandemic, each country is presented with both opportunities and cha... more In responding to the COVID‐19 pandemic, each country is presented with both opportunities and challenges, some unique and some shared with the global community. It is important to not only recognize, but to embrace them as drivers of the public to the current pandemic success. In this commentary, we discuss the opportunities and challenges that may affect ongoing public health programming in Australia within the current context of epidemiology. COVID‐19 within Australia has to date been effectively suppressed through the implementation of nationally coordinated, in which the state delivered public policy, guidelines and practice, and successful establishment of a comprehensive testing, contact tracing, patient isolation and contact quarantine regime combined with national and state social distancing, hygiene etiquette and movement restrictions. However, despite its success to date great challenges lay ahead for future public health policy with the threat of a second wave, or more li...
In this paper, we study the problem of joint inband backhauling and interference mitigation in 5G... more In this paper, we study the problem of joint inband backhauling and interference mitigation in 5G heterogeneous networks (HetNets) in which a massive multiple-input multipleoutput (MIMO) macro cell base station equipped with a large number of antennas, overlaid with self-backhauled small cells is assumed. This problem is cast as a network utility maximization subject to wireless backhaul constraints. Due to the non-tractability of the problem, we first resort to random matrix theory to get a closed-form expression of the achievable rate and transmit power in the asymptotic regime, i.e., as the number of antennas and users grows large. Subsequently, leveraging the framework of stochastic optimization, the problem is decoupled into dynamic scheduling of macro cell users and backhaul provisioning of small cells as a function of interference and backhaul links. Via simulations, we evaluate the performance gains of our proposed framework under different network architectures and low/high...
With the unprecedented growth in mobile data traffic and network densification, the emerging fift... more With the unprecedented growth in mobile data traffic and network densification, the emerging fifth-generation (5G) wireless network warrants a paradigm shift with respect to system design and technological enablers. In this regard, the prime motivation of this thesis is to propose an integrated access-backhaul (IAB) framework to dynamically schedule users, while efficiently providing a wireless backhaul to dense small cells and mitigating interference. In addition, joint resource allocation and interference mitigation solutions are proposed for two-hop and multi-hop self-backhauled millimeter wave (mmWave) networks. The first contribution of this thesis focuses on a multiuser two-hop relay cellular system in which a massive antenna array enabled macro base station (BS) simultaneously provides high beamforming gains to outdoor users, and wireless backhauling to outdoor small cells. Moreover, a hierarchical interference mitigation scheme is applied to efficiently mitigate cross-tier and cotier interference. In the second contribution, a multi-hop self-backhauled mmWave communication scenario is studied whereby a joint multi-hop multi-path selection and rate allocation framework is proposed to enable Gbps data rates with reliable communications. Using reinforcement learning techniques, a dynamic and efficient rerouting solution is proposed to cope with blockage and latency constraints. Finally, a risk-sensitive learning solution is leveraged to provide high-reliability and low-latency communications. In summary, the dissertation analyses key trade-offs between (i) capacity and latency, (ii) reliability and network density. Extensive simulation results were carried out to verify the performance gains of the proposed algorithms compared to several baselines and for different network settings. Key findings show significant improvements in terms of higher data rates, lower latency, and reliable communications with some trade-offs.
For emerging applications such as wireless video cameras, wireless low-power surveillance network... more For emerging applications such as wireless video cameras, wireless low-power surveillance networks, and disposable video cameras for medical applications. DVC is useful and maybe the best choice. Since the primary objective of DVC is low-complexity video encoding, the bulk of computation is shifted (transmitted) to the decoder, as opposed to a low-complexity decoder in conventional video compression standards such as H.264 and MPEG. Besides the low bit rate, the transmission has to be very secure also. That means the complexity of the used keys should be rather high and the keyspace has to be large to provide enough individual keys for a large wireless sensor network.
Global Journal of Engineering and Technology Advances, 2021
The problem of heating slab is a very important and highly applicable problem in the material pro... more The problem of heating slab is a very important and highly applicable problem in the material processing industry. This paper presents a method to design a PID controller according to the characteristic polynomial method to control the temperature for slab based on the transfer function model. The parameters of the PID controller are determined based on the parameters of the slab model, the heating furnace model, the converter model. The simulation results show that: the PID controller is capable of controlling the temperature of the slab to the desired temperature without over-adjusting.
Millimeter Wave (mmWave) systems are considered as one of the key technologies in future wireless... more Millimeter Wave (mmWave) systems are considered as one of the key technologies in future wireless systems due to the abundant spectrum resources in mmWave band. With the aim of achieving the capacity requirements in vehicular networks, large antenna arrays can be deployed at both the road side units (RSUs) side and the vehicles side. However, dynamic blockage caused by mobile obstacles in mmWave bands may hinder the system reliability. In this work, we study the temporal effects of dynamic blockage in vehicular networks and propose a deep reinforcement learning framework to overcome dynamic blockage. By dynamically adjusting blockage detection parameters and making intelligent handover decisions according to the observed states, system reliability can be significantly improved. Simulation results based on ray-tracing channel data show that the proposed scheme reduces the violation probability by 28.9% over conventional schemes.
With the emergence of data markets, data have become an asset that is used as part of transaction... more With the emergence of data markets, data have become an asset that is used as part of transactions. Current data markets rely on trusted third parties to manage the data, creating single points of failure with possibly disastrous consequences on data privacy and security. The lack of technical solutions to enforce strong privacy and security guarantees leaves the data markets' stakeholders (e.g., buyers and sellers of data) vulnerable when they transact data. Smart Contracts and Multi-Party Computation represent examples of emerging technologies that have the potential to guarantee the desired levels of data privacy and security. In this paper, we propose an architecture for data markets based on Smart Contracts and Multi-Party Computation and present a proof of concept prototype developed to demonstrate the feasibility of the proposed architecture.
IEEE Transactions on Wireless Communications, 2017
We study the problem of joint load balancing (user association and user scheduling) and interfere... more We study the problem of joint load balancing (user association and user scheduling) and interference management (beamforming design and power allocation) in heterogeneous networks (HetNets) in which massive multiple-input multipleoutput (MIMO) macro cell base station (BS) equipped with a large number of antennas, overlaid with wireless self-backhauled small cells (SCs) are assumed. Self-backhauled SC BSs with fullduplex communication employing regular antenna arrays serve both macro users and SC users by using the wireless backhaul from macro BS in the same frequency band. We formulate the joint load balancing and interference mitigation problem as a network utility maximization subject to wireless backhaul constraints. Subsequently, leveraging the framework of stochastic optimization, the problem is decoupled into dynamic scheduling of macro cell users, backhaul provisioning of SCs, and offloading macro cell users to SCs as a function of interference and backhaul links. Via numerical results, we show the performance gains of our proposed framework under the impact of SCs density, number of BS antennas, and transmit power levels at low and high frequency bands. It is shown that our proposed approach achieves a 5.6× gain in terms of cell-edge performance as compared to the closed-access baseline in ultra-dense networks with 350 SC BSs per km 2 .
Ultra-reliability and low-latency are two key components in 5G networks. In this letter, we inves... more Ultra-reliability and low-latency are two key components in 5G networks. In this letter, we investigate the problem of ultra-reliable and low-latency communication (URLLC) in millimeter wave (mmWave)-enabled massive multiple-input multipleoutput (MIMO) networks. The problem is cast as a network utility maximization subject to probabilistic latency and reliability constraints. To solve this problem, we resort to the Lyapunov technique whereby a utility-delay control approach is proposed, which adapts to channel variations and queue dynamics. Numerical results demonstrate that our proposed approach ensures reliable communication with a guaranteed probability of 99.99%, and reduces latency by 28.41% and 77.11% as compared to baselines with and without probabilistic latency constraints, respectively. Index Terms-5G, massive MIMO, mmWave, ultra-reliable low latency communications (URLLC). I. INTRODUCTION C URRENTLY, millimeter wave (mmWave) and massive multiple-input multiple-output (MIMO) techniques are investigated to provide reliable communication with an overthe-air latency of few milliseconds and extreme throughput [1]. While massive MIMO with large degrees of freedom provides high energy and spectral efficiency [2], mmWave frequency bands provide large bandwidth [3]. In addition, due to the short wavelength of mmWaves, large antenna array can be packed into highly directional beamforming, which makes massive MIMO practically feasible [4]. Thus far, most of existing works on mmWave-enabled massive MIMO systems focus mainly on providing capacity improvement [4], while latency and reliability are not addressed. Although latency and reliability are applicable to many scenarios (e.g. mission-critical applications), in this work, we are interested in the integration of mmWave communication and massive MIMO techniques, which holds the promise of providing great enhancements of the overall system performance [1], [2], [4]. Specifically, this letter is concerned with addressing the fundamental question in mmWave-enabled massive MIMO systems: "how to simultaneously provide order of magnitude capacity improvements and latency reduction?"
Model order reduction is a research direction which has provided interest to many scientists rece... more Model order reduction is a research direction which has provided interest to many scientists recently. A large number of order reduction algorithms have been introduced in many different approaches among which retaining the important poles of the original system in the reduced root system is a dominant approach with many advantages. This paper presents a new model in order reduction algorithm for both stable and unstable systems, based on the idea of keeping the dominant poles of the original system in the order reduction process. This algorithm transforms matrix A of the higher-order original system to upper-triangle matrix on which the poles are arranged basically on H -and 2 H-mixed dominant index on the main diagonal of the upper-triangle matrix so that error becomes small and the dominant poles are preserved. The illustration shows the correctness of the model order algorithm.
Heterogeneous hetworks (HetNets) have been introduced as an emerging technology in order to meet ... more Heterogeneous hetworks (HetNets) have been introduced as an emerging technology in order to meet the increasing demand for mobile data. HetNets are a combination of multi-layer networks such as macrocells and small cells. In such networks, users may suffer significant cross-layer interference. To manage this interference, the 3rd Generation Partnership Project (3GPP) has introduced enhanced Inter-Cell Interference Coordination (eICIC) techniques. Almost Blank SubFrame (ABSF) is one of the time-domain techniques used in eICIC solutions. We propose a dynamically optimal Signal-to-Interference-and-Noise Ratio (SINR)-based ABSF framework to ensure macro user performance while maintaining small user performance. We also study cooperative mechanisms to help small cells collaborate efficiently in order to reduce mutual interference. Simulations show that our proposed scheme achieves good performance and outperforms the existing ABSF frameworks.
Rhamnolipid is a biosurfactant produced by several Pseudomonas species, and can wet hydrophobic s... more Rhamnolipid is a biosurfactant produced by several Pseudomonas species, and can wet hydrophobic soils by lowering the cohesive and/or adhesive surface tension. Because of its biodegradability, rhamnolipid is believed to have minimal adverse impact on the soil and groundwater after usage. Applications of rhamnolipid to improve irrigation in agricultural soils thus have obvious advantages over other chemical wetting agents, especially under drought conditions. Due to global warming, soil amendment with biochar has been commonly practiced in agricultural soils to increase the soil water-holding capacity. As such, rhamnolipid transport in biochar-amended agricultural soils needs to be characterized. In this research, we found that rhamnolipid transport in biochar-amended agricultural soils was hindered by retardation (equilibrium adsorption) and deposition (kinetic adsorption), which was well represented by the advection-dispersion equation based on a local equilibrium assumption. A linear equilibrium adsorption was assumed in the advection-dispersion equation simulation, which was proved to be acceptable by studying the breakthrough curves. Both rhamnolipid equilibrium adsorption and kinetic adsorption increased with the increase of the biochar content in the agricultural soil.
Large particle sizes having a strong light scattering lead to a significantly decreased surface a... more Large particle sizes having a strong light scattering lead to a significantly decreased surface area and small particle sizes having large surface area lack light-scattering effect. How to combine large and small particle sizes together is an interesting work for achieving higher solar efficiency. In this work, we investigate the solar performance influence of the dye-sensitized solar cells (DSSCs) by the multiple titanium oxide (TiO2) layers with different particle sizes. It was found that the optimal TiO2thickness depends on the particle sizes of TiO2layers for achieving the maximum efficiency. The solar efficiency of DSSCs prepared by triple TiO2layers with different particle sizes is higher than that by double TiO2layers for the same TiO2thickness. The choice of particle size in the bottom layer is more important than that in the top layer for achieving higher solar efficiency. The choice of the particle sizes in the middle layer depends on the particle sizes in the bottom and t...
Localization of a needle tip is important for biopsy examinations in clinics. However, the needle... more Localization of a needle tip is important for biopsy examinations in clinics. However, the needle tip is sometimes difficult to discern under the guidance of sonography due to its poor visibility. A mini actuator that radiates a low-intensity ultrasound wave was manufactured using micro-electro-mechanical system (MEMS) technology. Interference between the radiated and diagnostic ultrasound pulses was observed as bright lines in the B-mode ultrasound image, from which the mini actuator could be recognized with ease. Because the distance between the mini actuator and the needle tip is fixed, the needle tip can be determined despite its inconsistent appearance in the sonography. Both gel phantom and ex vivo tissue evaluation showed that the needle tip can be determined reliably utilizing the acoustic interference pattern.
Bacterial transport in the subsurface is controlled by their interactions with the surrounding en... more Bacterial transport in the subsurface is controlled by their interactions with the surrounding environment, which are determined by the surface properties of the geological formation and bacterial surfaces. In this research, surface thermodynamic properties of Escherichia coli and the geological formation of aluminosilica clays were characterized based on contact angle measurements, which were utilized to quantify the distance-dependent interactions between E. coli and the geological formation according to the traditional and extended Derjaguin, Landau, Verwey and Overbeek (DLVO) theory. E. coli attachment to aluminosilica clays was evaluated in laboratory columns under saturated and steady-state flow conditions. E. coli deposition coefficient and desorption coefficient were simulated using convection-dispersion transport models against E. coli breakthrough curves, which were then linked to interactions between E. coli and the geological formation. It was discovered that E. coli deposition was controlled by the long-ranged electrostatic interaction and E. coli desorption was attributed to the short-ranged Lifshitz-van der Waals and Lewis acid-base interactions. E. coli transport in three layers of different alumino-silica clays was further examined and the breakthrough curve was simulated using E. coli deposition coefficient and desorption coefficient obtained from their individual column experiments. The well-fitted simulation confirmed that E. coli transport observations were interaction-dependent phenomena between E. coli and the geological formation.
2013 IEEE 8th Conference on Industrial Electronics and Applications (ICIEA), 2013
Development of balanced control for the twowheeled mobile robot has attracted many researchers in... more Development of balanced control for the twowheeled mobile robot has attracted many researchers in the recent years. One difficulty for this control problem is that the controlling object is always unstable and is affected by interferences. To solve this problem, the authors of the previous research offer use robust control algorithm H ∞. However, the two-wheeled mobile robot balancing controller under H ∞ robust control algorithms often has high order, complexity which will be significant when programming for controller and impact on quality in the process of factual control. This paper has proposed a new algorithm for reducing model orders in general and applying to reduce orders of controller in balance control of twowheeled robot in particular. Proposed order reduction model algorithm can be applied in other fields such as digital signal processing Keywords-the two-wheeled mobile robot, robust control algorithms, reducing model order, balanced control I.
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