Open Access. Powered by Scholars. Published by Universities.®
Science and Technology Studies Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 30 of 51
Full-Text Articles in Science and Technology Studies
Integration Of Plug-In Electric Vehicles Into Microgrids As Energy And Reactive Power Providers In Market Environment, Abdorreza Rabiee, Hassan Feshki Farahani, Mohammad Khalili, Jamshid Aghaei, Kashem M. Muttaqi
Integration Of Plug-In Electric Vehicles Into Microgrids As Energy And Reactive Power Providers In Market Environment, Abdorreza Rabiee, Hassan Feshki Farahani, Mohammad Khalili, Jamshid Aghaei, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
The concept of electricity markets in the deregulated environment generally refers to energy market and reactive power market is not paid attention as much as it deserves to. However, reactive power plays an important role in distribution networks to improve network conditions such as voltage profile improvement and loss reduction. Plug-in electric vehicles (PEVs) are mobile sources of active and reactive power, capable of being participated in energy market, and also in reactive power market without battery degradation. Active and reactive powers are coupled through the ac power flow equations and branch loading limits, as well as PEVs and synchronous …
A High Availability Application Service Platform For Nuclear Power Enterprises, Zhe Sun, He Jin, Jianming Yong, Salim Al Isma'ili, Changying Li, Jun Shen
A High Availability Application Service Platform For Nuclear Power Enterprises, Zhe Sun, He Jin, Jianming Yong, Salim Al Isma'ili, Changying Li, Jun Shen
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a High Availability Application Service Platform (HAASP) and analyses its high availability. The architecture of this platform contains application server platform and high availability architecture. Application server platform consists of three major components, application release platform, which is implemented with WebLogic and WebSphere cluster, application and database platforms, which are built with Oracle RAC, and IBM Domino cluster. High availability architecture is constructed by virtual machines, distributed switches and storage pools. It employs virtualization technology to integrate physical servers and storages, where physical servers are responsible for the creation of virtual server cluster, distributed switches, storage pool …
A New Approach To Reduce The Expected Energy Not Supplied In A Power Plant Located In A Non-Expandable Transmission System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili
A New Approach To Reduce The Expected Energy Not Supplied In A Power Plant Located In A Non-Expandable Transmission System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili
Faculty of Engineering and Information Sciences - Papers: Part A
The main objective of most of power plants is to inject power as much as possible into the grid from the power plants. However, the transmission system may restrain the output capability of the power plant, especially, if the power plant is located in an area of non-expandable transmission system. In this situation, any disturbance in the nearby transmission system may force the plant to generate lower than its rated value, which disables it from selling the remaining available generated power to the costumers and also increases the cost of energy not supplied. In this paper, an efficient method is …
Characteristics Of Power Quality Disturbances In Australia: Voltage Dips At Low-Voltage Sites, Sean T. Elphick, Victor W. Smith, Victor J. Gosbell, Sarath Perera, Philip Ciufo, Gerrard M. Drury
Characteristics Of Power Quality Disturbances In Australia: Voltage Dips At Low-Voltage Sites, Sean T. Elphick, Victor W. Smith, Victor J. Gosbell, Sarath Perera, Philip Ciufo, Gerrard M. Drury
Faculty of Engineering and Information Sciences - Papers: Part A
Voltage dips are considered to be one of the costliest of all power quality disturbances due to their disruption of industrial and commercial operations. The ability to characterise the voltage dip performance of distribution networks has many benefits for industry. There is considerable potential for industry to make large economic gains if voltage dip behaviour can be better understood and planned for. To put strategies in place to deal with voltage dips, there is a need for extensive data collection and analysis so that correct planning decisions can be made. This study details the characteristics of voltage dip data which …
A New Approach To Reduce The Non-Linear Characteristics Of A Stressed Power System By Using The Normal Form Technique In The Control Design Of The Excitation System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili
A New Approach To Reduce The Non-Linear Characteristics Of A Stressed Power System By Using The Normal Form Technique In The Control Design Of The Excitation System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, a new approach is presented to reduce the nonlinear characteristics of a stressed power system by reducing its second-order modal interaction through retuning some parameters of the generator excitation system. In order to determine the second-order modal interaction of the system, a new index on nonlinearity is developed using normal form theory. Using the proposed index of nonlinearity, a sensitivity function is formed to indicate the most effective excitation system parameters in the nonlinear behavior of the system. These dominant parameters are tuned to reduce the second-order modal interaction of the system and to reduce the index …
Power Generation Analysis Of Powerwindow, A Linear Wind Generator, Using Computational Fluid Dynamic Simulations, Seyed A. Jafari, Farzad Safaei, Buyung Kosasih, K C. Kwok
Power Generation Analysis Of Powerwindow, A Linear Wind Generator, Using Computational Fluid Dynamic Simulations, Seyed A. Jafari, Farzad Safaei, Buyung Kosasih, K C. Kwok
Faculty of Engineering and Information Sciences - Papers: Part A
A new linear wind generator (LWG), named PowerWindow, is introduced. The modular and scalable LWG is capable of generating power in low wind velocity condition, and hence can be an effective and safe power generator in built environments. The aerodynamic mechanism of the LWG power generation is elucidated using computational fluid dynamic (CFD) simulations, and the results are validated against the experimental data obtained from the prototype wind tunnel tests. The simulations provide important insights into the flow field in and around LWG particularly over the front and rear blades and how each one contributes to the power generation. This …
A Decentralized Multiagent-Based Voltage Control For Catastrophic Disturbances In A Power System, Sk. Razibul Islam, Kashem M. Muttaqi, Danny Sutanto
A Decentralized Multiagent-Based Voltage Control For Catastrophic Disturbances In A Power System, Sk. Razibul Islam, Kashem M. Muttaqi, Danny Sutanto
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, a multiagent-based voltage and reactive power control in the case of a multiple contingency is presented. Incorporating the agent-based autonomous feature to the intelligence of the remote terminal units, the present power system control structure can be used to help in preventing system voltage collapse during catastrophic disturbances. The control algorithm is based on a decentralized architecture of intelligent agents and the determination of a local zone that can carry out quick countermeasures in a decentralized manner as a multiagent system (MAS) during an emergency situation. An adaptive determination of the local zones undergoing voltage collapse has …
Summary Of The Economic Impacts Of Power Quality On Consumers, Sean T. Elphick, Philip Ciufo, Victor W. Smith, Sarath Perera
Summary Of The Economic Impacts Of Power Quality On Consumers, Sean T. Elphick, Philip Ciufo, Victor W. Smith, Sarath Perera
Faculty of Engineering and Information Sciences - Papers: Part A
The quality of the electrical supply has a direct impact on the correct function and operation of equipment connected to the public electricity supply network. There is an expectation that devices will operate as designed and that equipment lifetime should, statistically, be close to the designed value. The reliability of the network is generally assumed to be high enough so as to not cause unacceptable issues with regard to loss of production or loss of functionality. Quantifying the cost to the consumer when the supply power quality or reliability are not as expected is an important metric and can be …
Direct Power Control Of Dfig Based Wind Turbine Based On Wind Speed Estimation And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, S Roozbehani, F Najaty, S Ghaemi, Yingjie Tan, Kashem M. Muttaqi
Direct Power Control Of Dfig Based Wind Turbine Based On Wind Speed Estimation And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, S Roozbehani, F Najaty, S Ghaemi, Yingjie Tan, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a direct power control (DPC) design of a grid connected doubly fed induction generator (DFIG) based wind turbine system in order to track maximum absorbable power in different wind speeds. A generalized regression neural network (GRNN) is used to estimate wind speed and thereby the maximum absorbable power is determined online as a function of wind speed. Finally the proposed DPC strategy employs a nonlinear robust sliding mode control (SMC) scheme to calculate the required rotor control voltage directly. The concept of sliding mode control is incorporated into particle swarm optimization (PSO) to determine inertial weights. The …
Simple Structure For Reactive Power Control Of Ac Photovoltaic Modules, Viet Thang Tran, Danny Sutanto, Kashem M. Muttaqi
Simple Structure For Reactive Power Control Of Ac Photovoltaic Modules, Viet Thang Tran, Danny Sutanto, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
The objective of this paper is to propose a simple structure for reactive power control (RPC) of AC Photovoltaic (AC PV) modules. With the proposed structure, a cost-effective microcontroller can be adopted to achieve an effective reactive power control in order to support the grid voltage within acceptable bounds by absorbing or supplying reactive power. Moreover, the sliding mode control (SMC) is adopted to enhance the current control's dynamic response and reduce the current harmonic distortion. Comprehensive simulation of an AC PV module connected to grid using PSIM software with different operation modes are used to demonstrate the control strategy. …
Enhanced Frequency Response Strategy For Pmsg Based Wind Energy Conversion System Using Ultracapacitor In Remote Area Power Supply Systems, Yingjie Tan, Kashem M. Muttaqi
Enhanced Frequency Response Strategy For Pmsg Based Wind Energy Conversion System Using Ultracapacitor In Remote Area Power Supply Systems, Yingjie Tan, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
The high penetration level of wind energy, and non-responsive nature of power electronic interfaced wind energy conversion system (WECS) during frequency variations may create significant stress on conventional generators in a wind-diesel hybrid remote area power supply (RAPS) system. Hence, it is a necessity for WECS to provide frequency support. However, conventional frequency control strategies being used for WECS may impose a severe stress to wind turbines. In this paper, an enhanced frequency response strategy is proposed for the permanent magnet synchronous generator (PMSG) based WECS to regulate RAPS system frequency jointly with its integrated ultracapacitors. The proposed frequency response …
On Using Wireless Power Transfer To Increase The Max Flow Of Rechargeable Wireless Sensor Networks, Tengjiao He, Kwan-Wu Chin, Sieteng Soh
On Using Wireless Power Transfer To Increase The Max Flow Of Rechargeable Wireless Sensor Networks, Tengjiao He, Kwan-Wu Chin, Sieteng Soh
Faculty of Engineering and Information Sciences - Papers: Part A
A key problem in Rechargeable Wireless Sensor Networks (WSNs) is determining the maximum amount of data that can be collected by a sink over a given time period. This maximum is constrained by link capacity and critically, by the available energy at each node. In this paper, we consider a novel approach to increase the maximum flow rate by exploiting recent advances in Wireless Power Transfer (WPT). Specifically, we deploy a finite number of WPT capable rovers next to bottleneck sensor nodes with the aim to increase the max flow rate of a WSN. We formulate a Mixed Integer Linear …
Suboptimal Mppt Control For Power Management In Pv-Diesel Remote Area Power Supply Systems, Yingjie Tan, Lasantha G. Meegahapola, Kashem M. Muttaqi
Suboptimal Mppt Control For Power Management In Pv-Diesel Remote Area Power Supply Systems, Yingjie Tan, Lasantha G. Meegahapola, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
Maximum power point tracking (MPPT) is commonly being used in solar-photovoltaic (PV) power generation systems to maximise solar energy extraction. In this paper it is proposed to operate the solar-PV system at the suboptimal MPPT to manage power balance in a remote area power supply (RAPS) system. This is performed based on three different operating modes: 1) Frequency control mode; 2) Active power control mode; 3) MPPT control mode. The operating modes are decided based on the load level and the operating mode of the diesel generator (i.e. synchronous condenser mode or generator mode). This power management strategy balances the …
A Noniterative Method To Estimate Load Carrying Capability Of Generating Units In A Renewable Energy Rich Power Grid, Md Abu Abdullah, Kashem M. Muttaqi, Ashish Agalgaonkar, Danny Soetanto
A Noniterative Method To Estimate Load Carrying Capability Of Generating Units In A Renewable Energy Rich Power Grid, Md Abu Abdullah, Kashem M. Muttaqi, Ashish Agalgaonkar, Danny Soetanto
Faculty of Engineering and Information Sciences - Papers: Part A
It is important to estimate the contribution of renewable generation units in the evaluation of system generation adequacy for power generation planning taking into account the demand and renewable generation correlation and uncertainty. The effective load carrying capability (ELCC) is usually used for this purpose. In this paper, a noniterative analytical method is proposed for estimating the peak load carrying capability (PLCC) and ELCC of conventional and renewable generation units. The proposed method is verified using the IEEE RTS and an electricity network in New South Wales, Australia, and the results are compared with other estimation methods. The results show …
Assessing Network Compliance For Power Quality Performance, Sean Elphick, Victor Gosbell, Victor Smith, Gerrard Drury, Robert Barr
Assessing Network Compliance For Power Quality Performance, Sean Elphick, Victor Gosbell, Victor Smith, Gerrard Drury, Robert Barr
Faculty of Engineering and Information Sciences - Papers: Part A
IEC standards suggest that a network is compliant if 95% of the sites are compliant. In many cases it is only practical to measure the PQ parameters of some of the sites in a network and to use statistical analysis. The paper examines the minimum number of monitored sites needed to demonstrate compliance with a prescribed degree of confidence - e.g. at the 95% confidence level. Analysis is made of samples extracted randomly from sites included in the Australian Long Term National PQ Survey. The required number of sites is found to vary with the PQ disturbance of concern and …
Characterisation Of Flicker Emission And Propagation In Distribution Networks With Bi-Directional Power Flows, D Perera, L Meegahapola, S Perera, P Ciufo
Characterisation Of Flicker Emission And Propagation In Distribution Networks With Bi-Directional Power Flows, D Perera, L Meegahapola, S Perera, P Ciufo
Faculty of Engineering and Information Sciences - Papers: Part A
With the increasing penetration levels of intermittent and fluctuating energy sources such as wind generating systems in the electricity grid, resulting voltage fluctuations and flicker can be expected to become an important power quality considerations. Due to significant bidirectional power flows resulting from large renewable power generation systems connected to downstream, voltage fluctuations may propagate from downstream to upstream. The work presented in this paper investigates and characterises flicker emission and propagation resulting from fluctuating generating sources connected to a distribution network. Mathematical models are developed for flicker emission under different generator control strategies and flicker propagation to upstream network. …
Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Faculty of Engineering and Information Sciences - Papers: Part A
The use of per-subcarrier antenna subset selection in OFDM wireless systems offers higher system capacity and/or improved link reliability.However, the implementation of the conventional per-subcarrier selection schememay result in significant fluctuations of the average power and peak power across antennas, which affects the potential benefits of the system. In this paper, power efficiency of high-power amplifiers and energy efficiency in per-subcarrier antenna selection MIMO-OFDM systems are investigated. To deliver the maximum overall power efficiency, we propose a two-step strategy for data-subcarrier allocation.This strategy consists of an equal allocation of data subcarriers based on linear optimization and peak-power reduction via cross-antenna …
Power Allocation Algorithm In Ofdm-Based Cognitive Radio Systems, Van Vinh Nguyen, Yang Shouyi, Le Chung Tran
Power Allocation Algorithm In Ofdm-Based Cognitive Radio Systems, Van Vinh Nguyen, Yang Shouyi, Le Chung Tran
Faculty of Engineering and Information Sciences - Papers: Part A
In orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems, the optimized algorithms for sub-carrier power allocation face the problems of complex iterative calculation and difficult realization. In this paper, we propose an exponential power distribution function and derive a sub-optimal power allocation algorithm. This algorithm aims to allocate power of in-band subcarriers of cognitive users according to the numerical characteristics of the power distribution function by using a convex optimization numerical method under linear constraints. This algorithm has the advantages of fast calculation speed and easy realization, and reduces the interference to the authorized users, which is caused by …
Transmit Antenna Subset Selection For High-Rate Mimo-Ofdm Systems In The Presence Of Nonlinear Power Amplifiers, Phuc Ngoc Le, Farzad Safaei, Le Chung Tran
Transmit Antenna Subset Selection For High-Rate Mimo-Ofdm Systems In The Presence Of Nonlinear Power Amplifiers, Phuc Ngoc Le, Farzad Safaei, Le Chung Tran
Faculty of Engineering and Information Sciences - Papers: Part A
The deployment of antenna subset selection on a per-subcarrier basis in MIMO-OFDM systems could improve the system performance and/or increase data rates. This paper investigates this technique for the MIMO-OFDM systems suffering nonlinear distortions due to high-power amplifiers. At first, some problems pertaining to the implementation of this antenna selection approach, including power imbalance across transmit antennas and non-causality of per-subcarrier antenna selection criteria, are identified. Next, an optimal selection scheme is devised by means of linear optimization to overcome those disadvantages. This scheme optimally allocates data subcarriers under a constraint that all antennas have the same number of data …
A Review Of Technical Challenges In Planning And Operation Of Remote Area Power Supply Systems, Yingjie Tan, Lasantha Meegahapola, Kashem M. Muttaqi
A Review Of Technical Challenges In Planning And Operation Of Remote Area Power Supply Systems, Yingjie Tan, Lasantha Meegahapola, Kashem M. Muttaqi
Faculty of Engineering and Information Sciences - Papers: Part A
Remote area power supply (RAPS) systems are being used for many years to supply power to rural or remote communities where the utility grid is not accessible. In order to avoid the high operating cost and environmental impact caused by conventional generators, renewable energy resources are currently being utilised in RAPS systems. However, the intermittency of such renewable energy resources greatly impacts on planning and operation of RAPS systems. This paper aims to present a comprehensive review with regard to the RAPS system planning and operation techniques published in the literature. This paper summarises different modelling approaches associated with the …
Dispatch Strategy To Minimise Uncertainty In Wind Power Generation In The Australian National Electricity Market, Amila Wickramasinghe, Lasantha G. Meegahapola, Ashish P. Agalgaonkar, Sarath Perera
Dispatch Strategy To Minimise Uncertainty In Wind Power Generation In The Australian National Electricity Market, Amila Wickramasinghe, Lasantha G. Meegahapola, Ashish P. Agalgaonkar, Sarath Perera
Faculty of Engineering and Information Sciences - Papers: Part A
2014 ACPE. With increased penetration of wind power, scheduling generators to meet the forecast demand of a power system is becoming an increasingly challenging task for the system operators. Uncertainty associated with the generation expected from wind plants adds to the load demand uncertainty, making it necessary to retain additional reserves to maintain the balance between demand and supply of power. In the Australian national electricity market (NEM), sophisticated wind forecasting techniques are employed to reduce the uncertainty in wind generation. Despite being able to project the contribution of wind power to a reasonable accuracy, wind power plants are currently …
Smart Home Electricity Management In The Context Of Local Power Resources And Smart Grid, Weiliang Zhao, Lan Ding, Paul Cooper, Pascal Perez
Smart Home Electricity Management In The Context Of Local Power Resources And Smart Grid, Weiliang Zhao, Lan Ding, Paul Cooper, Pascal Perez
Faculty of Engineering and Information Sciences - Papers: Part A
This work proposes a smart home electricity management approach that can predict and schedule electricity demand and supply by considering: the 'state' of the smart grid, local power generation capacity, and electrical consumption of household appliances. The prediction of weather conditions and the immediate and longer-term plans of the residential home occupants are crucial parameters in the smart home decision-making system that acts on behalf of the occupants. This paper provides a motivation example and associated scenarios, electrical energy supply/demand models, formalization of the cost optimization problem, and scheduling schemes for a smart home electricity management system in the context …
Multi-Objective Reactive Power Support From Wind Farms For Network Performance Enhancement, Lasantha Meegahapola, Brendan Fox, Tim Littler, Damian Flynn
Multi-Objective Reactive Power Support From Wind Farms For Network Performance Enhancement, Lasantha Meegahapola, Brendan Fox, Tim Littler, Damian Flynn
Faculty of Engineering and Information Sciences - Papers: Part A
This paper examines the ability of the doubly fed induction generator (DFIG) to deliver multiple reactive power objectives during variable wind conditions. The reactive power requirement is decomposed based on various control objectives (e.g. power factor control, voltage control, loss minimisation, and flicker mitigation) defined around different time frames (i.e. seconds, minutes, and hourly), and the control reference is generated by aggregating the individual reactive power requirement for each control strategy. A novel coordinated controller is implemented for the rotor-side converter and the grid-side converter considering their capability curves and illustrating that it can effectively utilise the aggregated DFIG reactive …
A Multiagent Approach For Decentralized Voltage Regulation In Power Distribution Networks Within Dgs, Fenghui Ren, Minjie Zhang, Danny Sutanto
A Multiagent Approach For Decentralized Voltage Regulation In Power Distribution Networks Within Dgs, Fenghui Ren, Minjie Zhang, Danny Sutanto
Faculty of Engineering and Information Sciences - Papers: Part A
Voltage regulation (VR) is a procedure to keep voltages in a distribution network (DN) within normal limits. Conven- tionally, a voltage regulator can read voltage levels from pre- dened measures, and regulate the voltages. However, due to lacking of a distributed generator's (DG) information, the unexpected electricity from a DG will mislead readings on voltages levels, so as to disturb the VR in a DN. Adjust- ing a DG's reactive power output is an alternative way for VR. However, because of limited penetration levels, DGs need to collaborate with other devices in order to provide an eective voltage regulation. Therefore, …
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Faculty of Engineering and Information Sciences - Papers: Part A
Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind …
A Three-Phase Power Flow Approach For Integrated 3-Wire Mv And 4-Wire Multigrounded Lv Networks With Rooftop Solar Pv, Md J E Alam, K M. Muttaqi, Darmawan Sutanto
A Three-Phase Power Flow Approach For Integrated 3-Wire Mv And 4-Wire Multigrounded Lv Networks With Rooftop Solar Pv, Md J E Alam, K M. Muttaqi, Darmawan Sutanto
Faculty of Engineering and Information Sciences - Papers: Part A
With increasing level of rooftop solar photovoltaic (PV) penetration into low voltage (LV) distribution networks, analysis with realistic network models is necessary for adequate capturing of network behavior. Traditional three-phase 3-wire power flow approach lacks the capability of exact analysis of 4-wire multigrounded LV networks due to the approximation of merging the neutral wire admittance into the phase wire admittances. Such an approximation may not be desirable when neutral wire and grounding effects need to be assessed, especially in the presence of single-phase solar power injection that may cause a significant level of network unbalance. This paper proposes a three-phase …
A Unique Sandwich-Structured C/Ge/Graphene Nanocomposite As An Anode Material For High Power Lithium Ion Batteries, Dan Li, Kuok H. Seng, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Zaiping Guo
A Unique Sandwich-Structured C/Ge/Graphene Nanocomposite As An Anode Material For High Power Lithium Ion Batteries, Dan Li, Kuok H. Seng, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Zaiping Guo
Faculty of Engineering and Information Sciences - Papers: Part A
A unique sandwich-structured C/Ge/graphene composite with germanium nanoparticles trapped between graphene sheets is prepared by a microwave-assisted solvothermal reaction followed by carbon coating and thermal reduction. The graphene sheets are found to be effective in hindering the growth and aggregation of GeO2 nanoparticles. More importantly, the graphene sheets, coupled with the carbon coating, can buffer the volume changes of germanium in electrochemical lithium reactions. The unique sandwich structure features a highly conductive network of carbon, which can improve both the conductivity and the structural stability of the electrode material, and exemplifies a promising strategy for the development of new high …
Transmit Antenna Subset Selection With Power Balancing For High Data Rate Mimo-Ofdm Uwb Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Transmit Antenna Subset Selection With Power Balancing For High Data Rate Mimo-Ofdm Uwb Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Faculty of Engineering and Information Sciences - Papers: Part A
This paper proposes per-subcarrier transmit antenna subset selection with power balancing for MIMO-OFDM UWB systems to simultaneously improve the system error performance and increase data rates. The deployment of the per-subcarrier antenna subset selection may result in a power unbalance across antennas, which could cause power amplifiers (PAs) to operate in their non-linear regions. To overcome this disadvantage, we formulate a linear optimization problem for the optimal allocation of data subcarriers under a constraint that all antennas have the same number of assigned data symbols. This optimization problem could be applied to systems with an arbitrary number of multiplexed data …
Characteristics Of Power Quality Disturbances In Australia: Voltage Harmonics, S T. Elphick, V W. Smith, V J. Gosbell, S Perera
Characteristics Of Power Quality Disturbances In Australia: Voltage Harmonics, S T. Elphick, V W. Smith, V J. Gosbell, S Perera
Faculty of Engineering and Information Sciences - Papers: Part A
Management of harmonic voltage levels can impose significant economic impacts for both electricity suppliers and customers. For the case where harmonic voltage levels are high, economic costs include damage to equipment and associated loss of production due to high voltage harmonic levels as well as the costs associated with mitigation of harmonic currents, for example, harmonic filters. In the alternate scenario, ie. the case where harmonic voltage levels are acceptable, considerable expense may be incurred mitigating harmonic currents unnecessarily due to lack of knowledge of harmonic levels and/or network capabilities. As such, there is considerable potential for industry to make …
Size And Power Of Cointegration Tests With Non-Normal Garch Error Distributions, Chaiwat Kosapattarapim, Yan-Xia Lin, Michael Mccrae
Size And Power Of Cointegration Tests With Non-Normal Garch Error Distributions, Chaiwat Kosapattarapim, Yan-Xia Lin, Michael Mccrae
Faculty of Engineering and Information Sciences - Papers: Part A
Several tests for cointegration among non-stationary financial time series have been developed including the Dicky Fuller (1979) unit root tests, the Cointegration Regression Durbin-Watson test (1983), the Wild Bootstrap test (2003) and the Johansen likelihood ratio tests (1988). The Johensen's tests appeared to provide superior results when the tests were originally applied to situations where the cointegration errors were normally distributed. However, substantial empirical evidences show that financial time series tend to be nonnormal in their distribution which may, in turn, lead to non-normal GARCH type cointegration error distributions. The question addressed in this paper is whether the Johansen's tests …