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CSEE Journal of Power and Energy Systems 2024年第2期10卷 797-806页

作者： Edeh Vincent Mehdi Korki Mehdi Seyedmahmoudian alex stojcevski Saad Mekhilef School of Science Computingand Engineering TechnologiesSwinburne University of TechnologyMelbourneAustralia

The massive integration of communication and information technology with the large-scale power grid has enhanced the efficiency, safety, and economical operation of cyber-physical systems. However, the open and diversified communication environment of the smart grid is exposed to cyber-attacks. Data integrity attacks that can bypass conventional security techniques have been considered critical threats to the operation of the grid. Current detection techniques cannot learn the dynamic and heterogeneous characteristics of the smart grid and are unable to deal with non-euclidean data types. To address the issue, we propose a novel Deep-Q-Network scheme empowered with a graph convolutional network (GCN) framework to detect data integrity attacks in cyber-physical systems. The simulation results show that the proposed framework is scalable and achieves higher detection accuracy, unlike other benchmark techniques.

关键词： Deep reinforcement learning graph convolutional network heterogeneous smart grid network

Issues and mitigations of wind energy penetrated network:Australian network case study

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Journal of Modern Power Systems and Clean Energy 2018年第6期6卷 1141-1157页

作者： Asma AZIZ Aman Maung Than OO alex stojcevski Faculty of Science Engineering and Built EnvironmentSchool of Engineering Geelong Waurn Ponds CampusDeakin University Australia Faculty of Science Engineering and Technology School of Software and Electrical Engineering Swinburne University

Longest geographically connected Australian power system is undergoing an unprecedented transition,under the effect of increased integration of renewable energy systems. This change in generation mix has implications for the whole interconnected system designs, its operational strategies and the regulatory framework. Frequency control policies about real-time balancing of demand and supply is one of the prominent and priority operational challenge requiring urgent attention. This paper reviews the Australian electricity market structure in presence of wind energy and its governance. Various issues related to increased wind generation systems integration are discussed in detail. Currently applied mitigations along with prospective mitigation methods requiring new or improved policies are also discussed. It is concluded that developing prospective frequency regulation ancillary services market desires further encouraging policies from governing authority to keep pace with current grid transition and maintain its security.

关键词： Frequency regulation Inertia Rate of change of frequency Demand response Synchronous condenser

A Review on Primary and Secondary Controls of Inverter-interfaced Microgrid

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Journal of Modern Power Systems and Clean Energy 2021年第5期9卷 969-985页

作者： Kafeel Ahmed Mehdi Seyedmahmoudian Saad Mekhilef N.M.Mubarak alex stojcevski School of Software and Electrical Engineering Swinburne University of TechnologyVIC 3122VictoriaAustralia Power Electronics and Renewable Energy Research Laboratory Department of Electrical EngineeringUniversity of Malaya50603 Kuala LumpurMalaysia Department of Chemical Engineering Faculty of Engineering and ScienceCurtin University of Technology98009 SarawakMalaysia

The demand of electricity and environmental issues associated with conventional power generation plants are increasing *** technology has transformed the conventional power system through the integration of distributed generation(DG).With the help of modern power electronic technology,the conventional power system is able to support the integration of DGs based on renewable energy sources(RESs).The systematic combination of DGs with energy storage system forms a microgrid(MG),which can operate in islanded mode or grid-connected *** intermittent nature of RES and varying load pose substantial obstacles such as voltage and frequency instability,and the unreliability of *** feeder impedances and non-linear loads are considered as present challenges in MG *** control has been useful in undertaking solutions to these *** paper covers the deep insight of different control methods applied at the primary and secondary control levels in hierarchical *** primary control,the classification based on droop and non-droop controls is *** virtual synchronization machine(VSM)based control method is *** and frequency restoration control and economical operations at decentralized and centralized secondary control are analyzed in *** on the existing literature,critical discussion on MG control and future trends are also presented to provide future research perspectives.

关键词： Distributed generation(DG) hierarchical control droop control non-droop control inverter

Conics on Barth-Bauer octics

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Science China Mathematics 2024年第7期67卷 1507-1524页

作者： alex Degtyarev Department of Mathematics Bilkent UniversityAnkara06800Turkey

We analyze the configurations of conics and lines on a special class of Kummer octic surfaces. In particular, we bound the number of conics by 176 and show that there is a unique surface with 176 conics, all irreducible: it admits a faithful action of one of the Mukai groups. Therefore, we also discuss conics and lines on Mukai surfaces: we discover a double plane(ramified at a smooth sextic curve) that contains 8,910 smooth conics.

关键词： K3-surface octic surface Kummer surface conic Mukai group

Power Quality Analysis in Microgrid: An Experimental Approach

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Journal of Power and Energy Engineering 2016年第4期4卷 17-34页

作者： Arangarajan Vinayagam KSV Swarna Sui Yang Khoo alex stojcevski Faculty of Science Engineering and Built Environment Deakin University Geelong Australia Centre of Technology RMIT University Ho Chi Minh Vietnam

Microgrid (MG) integrated with Distributed Generation (DG) provides several benefits like reliable, secure, and high efficient of energy supply, while minimizing power loss, deferring expansion of power distribution infrastructures, and reduced carbon emission of energy supply etc. to the communities. Despite of the several benefits, there are several challenges existing due to the integration of different characteristics and technology of DG sources in MG network. Power Quality (PQ) issue is one of the main technical challenges in MG power system. In order to provide improved PQ of energy supply, it is necessary to analyse and quantify the PQ level in MG network. This paper investigates the detail of PQ impacts in a real MG network carried out through an experimental analysis. Voltage and frequency variations/deviations are analysed in both on-grid and off-grid mode of MG operation at varying generation and varying load conditions. Similarly unbalance voltage and current level in neutral are estimated at unbalanced PV generation and uneven load distribution in MG network. Also current and voltage THD are estimated at different PV power level. Finally the results obtained from the analysis are compared to that of Australian network standard level.

关键词： Microgrid Distributed Generation Power Quality Renewable Energy Total Harmonic Distortion

Developing the new soil science——Advice for early-career soil scientists

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Pedosphere 2024年第1期34卷 3-4页

作者： alex McBRATNEY Sydney Institute of Agriculture&School of Life and Environmental Sciences The University of SydneySydney NSW 2006Australia

Confucius said,“To know what you know and what you do not know, that is true knowledge.”Hartemink (2006) edited a prescient book on the future of soil science, the contents of which are worthy of consideration today. Since then, there has been a growing emphasis on soil carbon, soil health, and soil security, as well as increased capability of technology related to machine leaning and soil sensing and *** KNOWLEDGE DISCOVERY CATEGORISATION Based on the above ancient aphorism attributed to Confucius, the author writing in Hartemink (2006) classified soil knowledge and knowledge discovery into 4 categories. An updated version is given in Fig. 1.

关键词： soil measurement. leaning

Blast waveform tailoring using controlled venting in blast simulators and shock tubes

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Defence Technology（防务技术） 2024年第7期37卷 14-26页

作者： Edward Chern Jinn Gan alex Remennikov David Ritzel Faculty of Engineering and Information Sciences University of WollongongWollongongNSW2522Australia Dyn-FX Consulting Ltd 19 Laird Ave NorthAmherstburgONN9V 2T5Canada

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive *** tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance *** wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific *** paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube *** use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid *** venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast *** control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast *** paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

关键词： Advanced blast simulator Shock wave propagation Far-field explosion Blast loads Blast waves Computational fluid dynamics

No evidence of predator odor avoidance in a North American bird community

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Avian Research 2024年第1期15卷 133-138页

作者： Austin Dotta Batur Yaman alex Van Huynh Department of Biology DeSales University2755 Station AvenueCenter ValleyPAUSA

Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian *** studies investigating predator avoidance behaviors in response to predator odor cues have produced mixed results across species and *** we assess if a community of birds in eastern Pennsylvania displays avoidance behaviors towards predator odor cues in a natural foraging *** use clay caterpillars to measure foraging activity by birds in the presence of predator(bobcat)urine,non-predator(rabbit)urine,and water controls in two different environmental contexts(field ***).Although we detected a weak trend for birds to forage less at predator urine-treated sites,we found no significant difference in avian foraging between the site *** did find that foraging rates between environmental contexts changed significantly over the course of the experiment,with forest sites showing decreasing foraging rates and field sites showing increasing foraging *** results reinforce the published literature that avoidance of predator odors by birds may not be ubiquitous across contexts and species.

关键词： Foraging Odor Olfaction Predation Predator-avoidance

A pressure-sensitive rheological origin of high friction angles of granular matter observed in NASA–MGM project

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Chinese Physics B 2024年第6期33卷 559-567页

作者：程晓辉肖世泽杨森赵乃峰 alex Sixie Cao Department of Civil Engineering Tsinghua UniversityBeijing 100084China College of Transportation Engineering Nanjing Tech UniversityNanjing 211816China Institute of Structural Engineering ETH ZurichZurich 8092Switzerland

An abnormally high peak friction angle of Ottawa sand was observed in(National Aeronautics and Space Administration) NASA–(Mechanics of Granular Materials) MGM tests in microgravity conditions on the space shuttle. Previous investigations have been unsuccessful in providing a constitutive insight into this behavior of granular materials under extremely low effective stress conditions. Here, a recently proposed unified constitutive model for transient rheological behavior of sand and other granular materials is adopted for the analytical assessment of high peak friction angles. For the first time, this long-eluded behavior of sand is attributed to a hidden rheological transition mechanism, that is not only rate-sensitive, but also pressure-sensitive. The NASA–MGM microgravity conditions show that shear-tests of sand can be performed under abnormally low confining stress conditions. The pressure-sensitive behavior of granular shearing that is previously ignored is studied based on the μ(I) rheology and its variations. Comparisons between the model and the NASA microgravity tests demonstrate a high degree of agreement. The research is highly valid for pressure-sensitive and rate-dependent problems that occur during earthquakes, landslides, and space exploration.

关键词： granular matter microgravity pressure-sensitive NASA–MGM

PV Based Microgrid with Grid-Support Grid-Forming Inverter Control-(Simulation and Analysis)

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Smart Grid and Renewable Energy 2017年第1期8卷 1-30页

作者： Arangarajan Vinayagam K. S. V. Swarna Sui Yang Khoo Aman Than Oo alex stojcevski Faculty of Science Engineering and Built Environment Deakin University Geelong Australia Centre of Technology RMIT University Ho Chi Minh City Vietnam

Microgrid (MG) is a small entity of electrical network which comprises of various Distributed Generation (DG) sources, storage devices, and group of loads in various classes. MG provides reliable and secure energy supply to the critical loads of communities while operating either in on-grid or off-grid mode. In this study, a coordinated power management control strategy for a typical low voltage (LV) MG network with integration of solar Photovoltaic (PV) and storage facility has been developed and analysed in Matlab-Simu-link software environment at various modes (on-grid, off-grid, and on-grid to off-grid transition) of MG operation. Solar PV and battery power inverters are considered as grid-support grid-forming (GsGfm) Voltage Source Inverter (VSI) with the implementation of modified droop and virtual output impedance control strategies. Proposed control strategy supports coordinated control operation between PV units and battery storage, equal power sharing among the DG sources, and smooth MG mode transition with regulation of voltage and frequency level in MG network. In addition, voltage and current THD level were analysed and verified as per the standard of AS4777.

关键词： Microgrid Distributed Generation Power Management Power Sharing Grid-Support Grid-Forming Inverter