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Articles 1 - 30 of 46
Full-Text Articles in Social and Behavioral Sciences
Reflections From The Wearable Computing Conference In Toronto, Canada, Nick Rheinberger, Katina Michael, Alexander Hayes
Reflections From The Wearable Computing Conference In Toronto, Canada, Nick Rheinberger, Katina Michael, Alexander Hayes
Alexander Hayes Mr.
Could sports men and women who are monitored using wearable computers actually be playing to a global theatre to ensure the upkeep of their performance benchmarks instead of consciously watching and reacting to what is happening in the game they are playing? What are the social implications of heart rate monitors and GPS units now embedded into player clothing? What were some of the reflections from the IEEE ISTAS13 meeting on Wearable Computers in Every Day Life? What were some of the main messages that you walked away with from that conference? What made the greatest impression on us was …
The Ocean Thermal Energy Conversion Strategies And Analysis Of Current Challenges, Lasantha Meegahapola, Lanka Udawatta, Sanjeeva Witharana
The Ocean Thermal Energy Conversion Strategies And Analysis Of Current Challenges, Lasantha Meegahapola, Lanka Udawatta, Sanjeeva Witharana
Dr Lasantha G Meegahapola
This paper presents different roots of Ocean Thermal Energy Conversion (OTEC) strategies and challenges faced in terms of efficiency and economy of OTEC plants. The conversion strategies primarily focus on open cycle, closed cycle and hybrid plants. The efficiency studies mainly skew towards the effect of plant distance and thermal gradient towards plant efficiency. The economic analysis is based upon the effect of per unit cost for OTEC plant together with other important considerations such as Plant Factor (PF) and offshore distance, which determine the cost of power generation. Some illustrative examples are also provided using the derived equations under …
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Dr Lasantha G Meegahapola
The rapid growth of wind generation in many European countries is pushing power systems into uncharted territory. As additional wind generators are installed, the changing generation mix may impact on power system stability. This paper adopts the New England 39 bus system as a test system for transient stability analysis. Thermal generator models are based on a likely future plant mix for existing systems, while varying capacities of fixed-speed induction generators (FSIG) and doubly-fed induction generators (DFIG) are considered. The main emphasis here has been placed on the impact of wind technology mix on inter-area oscillations following transient grid disturbances. …
Optimal Power Flow With Variable Wind Conditions, S Durairaj, L Meegahapola, D Flynn, B Fox
Optimal Power Flow With Variable Wind Conditions, S Durairaj, L Meegahapola, D Flynn, B Fox
Dr Lasantha G Meegahapola
This paper presents simulation studies of an electric arc furnace (EAF) model in the MATLAB/SIMULINK environment. EAF was modeled as a current source controlled by a non-linear resistance. Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by EAF, has been a major power quality concern for both power companies and customers. A model was developed for the electric arc furnace and it was applied in the simulation studies of distribution static synchronous compensator (DSTATCOM) for voltage flicker mitigation. The controller for DSTATCOM was designed based on DQ-model for the reactive power management which helps in the mitigation of …
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Dr Lasantha G Meegahapola
This paper presents a voltage and power quality enhancement scheme for a doubly-fed induction generator (DFIG) wind farm during variable wind conditions. The wind profiles were derived considering the measured data at a DFIG wind farm located in Northern Ireland (NI). The aggregated DFIG wind farm model was validated using measured data at a wind farm during variable generation. The voltage control strategy was developed considering the X/R ratio of the wind farm feeder which connects the wind farm and the grid. The performance of the proposed strategy was evaluated for different X/R ratios, and wind profiles with different characteristics. …
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Dr Lasantha G Meegahapola
This paper analyzes the impact on transient and frequency stability for a power system at very high wind penetration (40% wind). Wind penetration is based on the doubly-fed induction generator (DFIG), and a systematic approach has been adopted for wind power integration. A sensitivity analysis has been carried out for each wind integration scenario and for different wind generator loading conditions. A range of fault locations has been selected for stability analysis based on the proximity to synchronous generation and wind farms. The analysis has shown that transient stability performance is subject to fault location in the network, especially when …
Optimal Allocation Of Reactive Power Resources To Minimise Losses And Maintain System Security, Eknath Vittal, Lasantha Meegahapola, Damian Flynn, Andrew Keane
Optimal Allocation Of Reactive Power Resources To Minimise Losses And Maintain System Security, Eknath Vittal, Lasantha Meegahapola, Damian Flynn, Andrew Keane
Dr Lasantha G Meegahapola
Modern doubly-fed induction generator (DFIG) wind turbines have significant reactive power control capability, even during low wind speed conditions. This can improve system security by providing terminal voltage control at buses in the system. Generally, such control employs the full range of reactive power production from the turbine which can lead to increased system losses. By utilizing optimal power flow analysis, and limiting the range of reactive power production at certain wind farms, system losses can be minimized. If the reactive power of the wind farms are optimized to achieve the minimum system losses this may adversely affect the voltage …
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
This paper presents transient stability analysis for a power system with high wind penetration. The transient stability has been evaluated based on two stability criteria: rotor angle stability and voltage stability. A modified IEEE-14 bus system has been used as the main study network and simulations have been conducted at several wind power penetration levels, defined as a fraction of total system generation. A wide range of scenarios have been presented based on the wind farm voltage at the point of connection, i.e. low voltage (LV) distribution level and high voltage (HV) transmission level, and the type of wind generator …
Active Use Of Dfig Based Wind Farms For Transient Stability Improvement During Grid Disturbances, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Active Use Of Dfig Based Wind Farms For Transient Stability Improvement During Grid Disturbances, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Dr Lasantha G Meegahapola
The doubly-fed induction generator (DFIG) now represents the dominant technology in wind turbine design. One consequence of this is limited damping and inertial response during transient grid disturbances. A 'decoupled' strategy is therefore proposed to operate the DFIG grid-side converter (GSC) as a static synchronous compensator (STATCOM) during a fault, supporting the local voltage, while the DFIG operates as a fixed-speed induction generator (FSIG) providing an inertial response. The modeling aspects of the decoupled control strategy, the selection of protection control settings, the significance of the fault location and operation at sub- and super-synchronous speeds are analyzed in detail. In …
Fuzzy Logic And Artificial Neural Network Approaches In Odor Detection, Lasantha Meegahapola, J Karunadasa, Kasun Sandasiri, Damith Tharanga, Dammika Jayasekara
Fuzzy Logic And Artificial Neural Network Approaches In Odor Detection, Lasantha Meegahapola, J Karunadasa, Kasun Sandasiri, Damith Tharanga, Dammika Jayasekara
Dr Lasantha G Meegahapola
This paper presents the research segment of development of methodology for determining odor level of various applications using two different concepts; Fuzzy logic based algorithm and Artificial Neural Network (ANN) based algorithm. Three different gas sensors are used which respond to ammonia (NH3), hydrogen sulfide (H2S) and methane (CH4). Sensory fusion is achieved through processing the analog to digital converted values of sensor outputs using the algorithm to determine the odor level of various types of predetermined odors. Olfactometry was used to determine the desired outputs (odor levels) of the algorithms. Fuzzy logic algorithm uses Zadeh-Mamdani type Fuzzy inference system …
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
Optimal fault ride-through (FRT) conditions for a doubly-fed induction generator (DFIG) during a transient grid fault are analyzed with special emphasis on improving the active power generation profile. The transition states due to crowbar activation during transient faults are investigated to exploit the maximum power during the fault and post-fault period. It has been identified that operating slip, severity of fault and crowbar resistance have a direct impact on the power capability of a DFIG, and crowbar resistance can be chosen to optimize the power capability. It has been further shown that an extended crowbar period can deliver enhanced inertial …
Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Ishraq Hamdan Alfadhli
This paper investigates why the observed critical Shields stress for incipient sediment motion deviates from the Shields curve. This deviation is often described in the literature as due to measurement errors and non-uniformity of channel-bed slope or flows. On the contrary, this paper hypothesises the deviation as due to the presence of vertical velocity in open channel flows. We found that the existence of vertical velocity in non-uniform flows can lead to the deviation of critical shear stress from the standard Shield's diagram that is valid only in uniform flows, and the channel bed slope could not contribute to the …
Performance Comparison Of Two Compact Multiplexed Readouts With Sensl's Spmarray4 For High-Resolution Detector Module, Yujin Qi, Xiaohui Zhang, Cuilan Zhao, Lihong Chen, Marco Petasecca, Mitra Safavi-Naeini, Michael Lerch, Anatoly Rosenfeld
Performance Comparison Of Two Compact Multiplexed Readouts With Sensl's Spmarray4 For High-Resolution Detector Module, Yujin Qi, Xiaohui Zhang, Cuilan Zhao, Lihong Chen, Marco Petasecca, Mitra Safavi-Naeini, Michael Lerch, Anatoly Rosenfeld
Michael L.F. Lerch
The purpose of this study was to investigate a compact readout for silicon photomultiplier (SiPM) array in the development of high-resolution imaging detector to reduce the readout channels while maximizing the detectors performance. The detector module was composed of a LYSO scintillation crystal array and a SensL's SPMArray4. The crystal array was coupled to the SiPM array with a 2mm-thick silicone pad to improve the light sharing among the SiPM array elements. Three LYSO crystal arrays of 4x4, 8x8 and 12x12 crystal elements with pixel sizes of 3.2, 1.6 and 1.0 mm were investigated in this study. Two compact multiplexed …
No Limits To Watching?, Katina Michael, M.G. Michael
No Limits To Watching?, Katina Michael, M.G. Michael
Professor Katina Michael
Little by little, the introduction of new body-worn technologies is transforming the way people interact with their environment and one another, and perhaps even with themselves. Social and environmental psychology studies of human-technology interaction pose as many questions as answers. We are learning as we go: 'learning by doing' through interaction and 'learning by being'. Steve Mann calls this practice existential learning; wearers become photoborgs, a type of cyborg (cybernetic organism) whose primary intent is image capture from the domains of the natural and artificial. This approach elides the distinction between the technology and the human; they coalesce into one.
Emergence Of Social Norms Through Collective Learning In Networked Agent Societies, Chao Yu, Minjie Zhang, Fenghui Ren, Xudong Luo
Emergence Of Social Norms Through Collective Learning In Networked Agent Societies, Chao Yu, Minjie Zhang, Fenghui Ren, Xudong Luo
Dr Fenghui Ren
Social norms play a pivotal role in sustaining social order by regulating individual behaviors in a society. In normative multiagent systems, social norms have been used as an efficient mechanism to govern virtual agent societies towards cooperation and coordination. In this paper, we study the emergence of social norms via learning from repeated local interactions in networked agent societies. We propose a collective learning framework, which imitates the opinion aggregation process in human decision making, to study the impact of agent local collective behaviors on norm emergence in different situations. In the framework, each agent interacts repeatedly with all of …
Agent-Based Demand Management In A Power Distribution Network By Considering Distributed Generations, Fenghui Ren, Minjie Zhang, Danny Soetanto
Agent-Based Demand Management In A Power Distribution Network By Considering Distributed Generations, Fenghui Ren, Minjie Zhang, Danny Soetanto
Dr Fenghui Ren
A distribution network carries electricity from transmission network to consumers through facilities such as substations, buses and feeders. Distributed generations emerge as the new alternative power resource to a distribution network at a smaller and distributed scale. On one hand, distributed generations can decrease substations' load and power price. On the other hand, they will bring difficulties to substations for demand management. This paper proposes a multiagent model to represent a radial distribution network. The model includes five types of agents, which are substation agents, bus agents, feeder agents, load agents and generation agents. Through communicating with neighbouring agents, each …
The Local Index Formula In Semifinite Von Neumann Algebras Ii: The Even Case, Alan Carey, John Phillips, Adam Rennie, F Sukochev
The Local Index Formula In Semifinite Von Neumann Algebras Ii: The Even Case, Alan Carey, John Phillips, Adam Rennie, F Sukochev
Associate Professor Adam Rennie
We generalise the even local index formula of Connes and Moscovici to the case of spectral triples for a ∗-subalgebra A of a general semifinite von Neumann algebra. The proof is a variant of that for the odd case which appears in Part I. To allow for algebras with a non-trivial centre we have to establish a theory of unbounded Fredholm operators in a general semifinite von Neumann algebra and in particular prove a generalised McKean-Singer formula.
Image Compression And Retrieval For Mobile Visual Search, Yi Cao, Christian Ritz, Raad Raad
Image Compression And Retrieval For Mobile Visual Search, Yi Cao, Christian Ritz, Raad Raad
Dr Raad Raad
Mobile Visual Search (MVS) is an emerging area of research given the explosion of smart and computationally powerful mobile devices. Typically, MVS involves the computation of local image features which are then used within a matching process. Such applications pose certain unique challenges due to computation, power and bandwidth constraints of the mobile device. This paper examines the trade-off between two general frameworks for implementing MVS: 1. sending compressed images and performing feature extraction and matching on a server; and 2. performing feature extraction on the mobile device and sending these to a server for matching. A number of local …
The Local Index Formula In Semifinite Von Neumann Algebras I: Spectral Flow, Alan Carey, John Phillips, Adam Rennie, Fyodor Sukochev
The Local Index Formula In Semifinite Von Neumann Algebras I: Spectral Flow, Alan Carey, John Phillips, Adam Rennie, Fyodor Sukochev
Associate Professor Adam Rennie
We generalise the local index formula of Connes and Moscovici to the case of spectral triples for a ∗-subalgebra A of a general semifinite von Neumann algebra. In this setting it gives a formula for spectral flow along a path joining an unbounded self-adjoint Breuer-Fredholm operator, affiliated to the von Neumann algebra, to a unitarily equivalent operator. Our proof is novel even in the setting of the original theorem and relies on the introduction of a function valued cocycle which is 'almost' a (b,B)-cocycle in the cyclic cohomology of A.
Session Based Differentiated Quality Of Service Admission Control For Web Servers, Yaya Wei, Chuang Lin, Fengyuan Ren, Eryk Dutkeiwicz, Raad Raad
Session Based Differentiated Quality Of Service Admission Control For Web Servers, Yaya Wei, Chuang Lin, Fengyuan Ren, Eryk Dutkeiwicz, Raad Raad
Dr Raad Raad
Recent advance-session based admission control (SBAC) has resulted in protecting the server from entering a regime in which latencies are excessive or session throughput collapses due to dropped requests and aborted sessions. The goal of this work is to introduce differentiated QoS to SBAC. We propose a two-threshold SBAC scheme (QSBAC). It can provide high throughput for preferred clients especially in overload situation. Furthermore, to adapt to varying traffic loads, a dynamic QSBAC (DQSBAC) scheme is also proposed. The experimental results show that comparing with SBAC scheme, both QSBAC scheme and DQSBAC scheme can sustain higher session throughput for preferred …
A Tutorial On The New Higher Order Rotation Spreading Matrix For Bsofdm, Ibrahim Raad, Xiaojing Huang, Raad Raad
A Tutorial On The New Higher Order Rotation Spreading Matrix For Bsofdm, Ibrahim Raad, Xiaojing Huang, Raad Raad
Dr Raad Raad
No abstract provided.
Securing Dsr Against Wormhole Attacks In Multirate Ad Hoc Networks, Shams Qazi, Raad Raad, Yi Mu, Willy Susilo
Securing Dsr Against Wormhole Attacks In Multirate Ad Hoc Networks, Shams Qazi, Raad Raad, Yi Mu, Willy Susilo
Dr Raad Raad
A wormhole attack is one of the hardest problems to detect whereas it can be easily implanted in any type of wireless ad hoc network. A wormhole attack can easily be launched by the attacker without having knowledge of the network or compromising any legitimate nodes. Most existing solutions either require special hardware devices or make strong assumptions in order to detect wormhole attacks which limit the usability of these solutions. In this paper, we present a security enhancement to dynamic source routing (DSR) protocol against wormhole attacks for ad hoc networks which relies on calculation of round trip time …
3d Mapping Using A Tof Camera For Self Programming An Industrial Robot, N Larkin, Zengxi Pan, S Van Duin, J Norrish
3d Mapping Using A Tof Camera For Self Programming An Industrial Robot, N Larkin, Zengxi Pan, S Van Duin, J Norrish
zengxi pan
Automated Offline Programing (AOLP) is a cost effective robot programming method. However, it relies on accurate CAD information of the work environment to perform optimally. Incorrect CAD data is a known source of error for AOLP systems. This paper introduces a new sensor based method of programming that extends the concept of AOLP. Using a ToF camera to map the environment, there is no reliance on CAD data. The problem of motion planning to efficiently map the environment is examined and changes to the motion planning algorithm are proposed and tested.
Optimising Layered Integrated Instructional Design Through The Application Of Cognitive Load Theory, Abdallah Alasraj, Mark Freeman, Paul Chandler
Optimising Layered Integrated Instructional Design Through The Application Of Cognitive Load Theory, Abdallah Alasraj, Mark Freeman, Paul Chandler
Dr Mark Freeman
This study examined the effect of cognitive load on knowledge construction through the use of web-based layered integrated instructional design techniques. The premise through using this approach was that it would better facilitate a learner’s schema development. This research focused on how the design of web-based integrated instructional materials can utilise the principles of Cognitive Load Theory (CLT), to optimise the learning process within the university environment for learning models of procedural tasks. The study compared three different layered integrated instructional designs to identify which approach had the greatest benefit on learning outcomes. The procedural task that was used involved …
Adaptive Sliding Mode Control Of Tri-Layer Conjugated Polymer Actuators, Xiangjiang Wang, Gursel Alici, Chuc Nguyen
Adaptive Sliding Mode Control Of Tri-Layer Conjugated Polymer Actuators, Xiangjiang Wang, Gursel Alici, Chuc Nguyen
Chuc Huu Nguyen
This paper proposes an adaptive sliding mode control methodology to enhance the positioning ability of conducting polymer actuators typified by tri-layer conjugated polymer actuators. This is motivated by the search for an effective control strategy to command such actuators to a desired configuration in the presence of parametric uncertainties and unmodeled disturbances. After analyzing the stability of the adaptive sliding mode control system, experiments were conducted to demonstrate its satisfactory tracking ability, based on a series of experimental results. Implementation of the control law requires a valid model of the conducting polymer actuator and boundaries of the uncertainties and disturbances. …
Electrochemical Behavior Of Mn3sn2 As Anode For Lithium Ion Batteries, Li Li, Rong Zeng, Christopher Cook, Zaiping Guo, Jianli Wang, Hua Liu
Electrochemical Behavior Of Mn3sn2 As Anode For Lithium Ion Batteries, Li Li, Rong Zeng, Christopher Cook, Zaiping Guo, Jianli Wang, Hua Liu
Jianli Wang
No abstract provided.
The Need For Deniability In Identification Schemes, Pairat Thorncharoensri, Qiong Huang, Man Ho Au, Willy Susilo, Guomin Yang, Yi Mu, Duncan Wong
The Need For Deniability In Identification Schemes, Pairat Thorncharoensri, Qiong Huang, Man Ho Au, Willy Susilo, Guomin Yang, Yi Mu, Duncan Wong
Dr Guomin Yang
With the increasing concern on the erosion of privacy in the society, privacy-preserving techniques have become a very essential issue. This paper provides a formal treatment of deniability in identification schemes. In particular, the contributions of this paper are three folds. Firstly, for the first time in the literature, we address the issue of deniability in identification scheme. Deniability ensures the prover's privacy even after the identification protocol completes. With the deniability property, it is assured that the verifier will not be able to convince any other third party that the prover has engaged in the identification protocol with the …
Rotation Patterns And Trend Estimation For Repeated Surveys Using Rotation Group Estimates, Craig Mclaren, David Steel
Rotation Patterns And Trend Estimation For Repeated Surveys Using Rotation Group Estimates, Craig Mclaren, David Steel
Professor David Steel
A general approach for constructing filters to produce trend estimates from a repeated survey is described. This approach accounts for the correlation structure induced by the rotation pattern used in the survey. Different filters are developed depending on whether the trend analysis is based on elementary estimates available for each rotation group or overall estimates obtained by combining the rotation group estimates. The properties of trend estimates obtained directly from the elementary estimates, those obtained from the simple average of the rotation group estimates and trend estimates obtained from the best linear unbiased estimates of the population characteristics of interest …
Ignoring A Level In A Multilevel Model: Evidence From Uk Census Data, Mark Tramner, David Steel
Ignoring A Level In A Multilevel Model: Evidence From Uk Census Data, Mark Tramner, David Steel
Professor David Steel
Because of the inherent multilevel nature of census data, it is often appropriate to use multilevel models to investigate relationships between census variables. For a local population, the data available from the census allow a three-level nested model to be assumed, with an individual level (level 1), an enumeration district (ED) level (level 2), and a ward level (level 3). The consequences of ignoring one of the three levels in this model are assessed here theoretically. Empirical results, based on 1991 UK Census data, are also provided, comparing the variance components estimated from the three-level model with analyses based on …
Analysis Combining Survey And Geographically Aggregated Data, David Steel, Mark Tranmer, D Holt
Analysis Combining Survey And Geographically Aggregated Data, David Steel, Mark Tranmer, D Holt
Professor David Steel
This chapter contains sections titled: Introduction and Overview Aggregate and Survey Data Availability Bias and Variance of Variance Component Estimators Based on Aggregate and Survey Data Simulation Studies Using Auxiliary Variables to Reduce Aggregation Effects Conclusions Acknowledgements