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Harmonic Impact Of Photovoltaic Inverters On Low Voltage Distribution Systems, Ahmed Latheef, D A. Robinson, Victor J. Gosbell, Victor W. Smith
Harmonic Impact Of Photovoltaic Inverters On Low Voltage Distribution Systems, Ahmed Latheef, D A. Robinson, Victor J. Gosbell, Victor W. Smith
Faculty of Informatics - Papers (Archive)
The number of installations of photovoltaic solar panels and associated inverter systems within residential premises is increasing. As these systems incorporate a power electronics front end, they will have an influence on the quality of supply in regards to voltage harmonics. This paper investigates the harmonic impact on an LV distribution feeder due to the installation of residential type grid connected photovoltaic inverter systems. To undertake the study an aggregated current source model is proposed for the photovoltaic inverter systems based on measurement data from available literature and the relevant international standards. A typical LV distribution feeder including load arrangements …
An Ontology-Based Approach For Expert And Knowledge Mining In Complex Multi-Agent Systems, Minjie Zhang, Xijin Tang, Quan Bai, Jifa Gu
An Ontology-Based Approach For Expert And Knowledge Mining In Complex Multi-Agent Systems, Minjie Zhang, Xijin Tang, Quan Bai, Jifa Gu
Faculty of Informatics - Papers (Archive)
Complex problems require diverse expertise and multiple techniques to solve. In order to solve such problems, complex multi-agent systems include numbers of heterogeneous agents, which may include both of human experts and autonomous agents, to work together toward some complex problems. Most complex multi-agent systems are working in open domains. Due to heterogeneities and dynamic working environments, expertise and capabilities of agents might not be well estimated and presented in the system. Therefore, how to discover useful knowledge from human and autonomous experts, make more accurate estimation for experts' capabilities and to find out suitable expert(s) to solve incoming problems …
Mindful It Adoption: Making The Right Strategic Decisions By Knowing Why And How To Adopt Enterprise Systems?, Valerie A. Baker, Tim Coltman
Mindful It Adoption: Making The Right Strategic Decisions By Knowing Why And How To Adopt Enterprise Systems?, Valerie A. Baker, Tim Coltman
Faculty of Informatics - Papers (Archive)
Corporate investment in enterprise level IT systems has been characterised by high rates of failure. The paper presents a knowledge based perspective to examine how firms adopt and implement enterprise systems in order to better understand how organisations can achieve reliable outcomes from such investments. The case presented explores the key decision stages of a major ERP investment, focusing on the strategic reasoning behind each decision. Particular attention is directed to the relationship between adoption know-why and implementation know-how to assess whether managers have been mindful or mindless in their investment decisions.
Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz A. Wysocki, Beata J. Wysocki, Jos H. Weber
Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz A. Wysocki, Beata J. Wysocki, Jos H. Weber
Faculty of Informatics - Papers (Archive)
Interleaved coding-modulation (ICM) is a recently proposed method for ultra-wideband impulse radio (UWB-IR) systems. ICM exploits the concept of chip interleaving, allowing to alleviate the problem of inter-symbol and inter-pulse interference commonly present in high data rate UWB-IR systems. In this paper, previous work on ICM is extended to scarcely populated multi-user scenarios. A novel design of a deterministic chip interleaver based on time-hopping hyperbolic congruence sequences is proposed. Furthermore, the main parameters of the random and hyperbolic interleavers are reviewed. The obtained results indicate that the proposed type of interleaver yields similar performance to random interleavers but with the …
N-Gens Of Change: Personal Response Systems And Net-Generation Students, Brian Murphy, Ciorstan J. Smark
N-Gens Of Change: Personal Response Systems And Net-Generation Students, Brian Murphy, Ciorstan J. Smark
Faculty of Commerce - Papers (Archive)
Personal Response Systems are a technology similar to use to a television remote control or a mobile telephone for sending SMS messages. They enable almost instant communication between student and instructor in lecture situations. This paper examines the claims made by Personal Response Systems and considers whether they may be especially appropriate to the preferences and expectations of Net- Generation students. The Net-Generation (also known as N-Gens) is made up of students born between 1981 and 2001. They now make up the bulk of finance students in universities across our region. But have we really adapted our lecturing styles to …
Robust Motion Tracking Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Robust Motion Tracking Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Faculty of Engineering - Papers (Archive)
This paper proposes a robust control methodology for piezoelectric actuation systems to track specified motion trajectories. This is motivated by the search for an effective control strategy to deal with the problem of nonlinear behaviour in the piezoelectric actuation systems. The basic concept associated with this approach lies in the specification of a target performance and the formulation of a robust control scheme for the system to ensure the convergence of the position tracking error to zero in the presence of parametric uncertainties and hysteresis effect inclusive of other un-modelled disturbances. Stability of the control system is proven theoretically and …
Control Strategy Of Distributed Generation For Voltage Support In Distribution Systems, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich
Control Strategy Of Distributed Generation For Voltage Support In Distribution Systems, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich
Faculty of Engineering and Information Sciences - Papers: Part A
Voltage problem is always a critical issue in operating a distribution system. The uncertainties of load distribution and variation have introduced a great complexity to the task of maintaining system voltage within the permitted range. In this paper, small-scale generator, known as distributed generation (DG), is employed in the system and acting as a voltage regulator. The output of DG is controlled in such a way that acceptable level of electrical supply quality is achieved with a reasonable operating cost. The DG controller is tested with a non-uniformly varying load on the time domain basis. Simulations have been conducted with …
Experience In The Application Of Iec/Tr 61000-3-6 To Harmonic Allocation In Transmission Systems, T J. Browne, V J. Gosbell, S Perera, D A. Robinson, L M. Falla, P J. Windle, A C. D Perera
Experience In The Application Of Iec/Tr 61000-3-6 To Harmonic Allocation In Transmission Systems, T J. Browne, V J. Gosbell, S Perera, D A. Robinson, L M. Falla, P J. Windle, A C. D Perera
Faculty of Engineering and Information Sciences - Papers: Part A
Technical report IEC/TR 61000-3-6 is widely used as a guide to harmonic management in HV and MV networks, assisting in coordination of harmonic levels between utility and customer. In 2001, Australia and New Zealand adopted the harmonic standard AS/NZS 61000.3.6, which closely follows the above IEC technical report. As a result, transmission utilities and connected loads are required by government regulations to abide by the harmonic allocations set by the standard. The technical report contains some useful general principles which can be applied to the harmonic management of power systems. However, unexpected difficulties can be found when attempts are made …
Distributed Generation For Minimization Of Power Losses In Distribution Systems, Kashem M. Muttaqi, An D. T Le, Michael Negnevitsky, Gerard Ledwich
Distributed Generation For Minimization Of Power Losses In Distribution Systems, Kashem M. Muttaqi, An D. T Le, Michael Negnevitsky, Gerard Ledwich
Faculty of Engineering and Information Sciences - Papers: Part A
Appropriate size and location of distributed generation (DG) play a significant role in minimizing power losses in distribution systems. This paper represents techniques to minimize power losses in a distribution feeder by optimizing DG model in terms of size, location and operating point of DG. Sensitivity analysis for power losses in terms of DG size and DG operating point has been performed. The proposed sensitivity indices can indicate the changes in power losses with respect to DG current injection. The proposed techniques have been developed with considering load characteristics and representing loads with constant impedance and constant current models, separately. …
Experimental Evaluation Of Adaptive And Variable Structure Control Of Piezoelectric Actuation Systems For Micro/Nano Manipulation, Hwee Choo Liaw, Bijan Shirinzadeh, Denny Oetomo, Gursel Alici
Experimental Evaluation Of Adaptive And Variable Structure Control Of Piezoelectric Actuation Systems For Micro/Nano Manipulation, Hwee Choo Liaw, Bijan Shirinzadeh, Denny Oetomo, Gursel Alici
Faculty of Engineering - Papers (Archive)
This paper proposes and evaluates an adaptive technique and a variable structure control approach for piezoelectric actuation systems to track specified motion trajectories. The proposed control methodologies are formulated to accommodate unknown or uncertain system parameters, nonlinearities including the hysteresis effect, and external disturbances in the piezoelectric actuation systems without any form of feed-forward compensation. In this study, both control methodologies are demonstrated to possess a promising motion tracking ability experimentally. In comparison, the variable structure control approach is evaluated to be superior to the adaptive technique in the motion tracking control. With the ability to track motion trajectories under …