Digital Commons Network^™

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

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

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

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

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

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

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

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

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

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

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 …

Giant Interlayer Magnetoresistances And Strong Anisotropy In P-Type Sb2te3 Single Crystals, Zengji Yue, Xiaolin Wang, S Dou

Zengji Yue

Anisotropic interlayer magneto-transport properties have been studied over a broad range of temperatures and magnetic fields in p-type Sb2Te3 single crystals. Giant interlayer magnetoresistance (MR) of up to 400% was observed, which exhibits quadratic field dependences in low fields and becomes linear at high fields without any trend towards saturation. The interlayer MR displays strong anisotropy and is attributable to the anisotropy of the Fermi surface. The observed giant anisotropic interlayer MR could find applications in p-type Sb2Te3 based magneto-electronic devices.

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 …

Comparison Of The New Moskin Detector And Fiber Optic Dosimetry System For Radiotherapy, Ian Kwan, Bong Soo Lee, Wook Jae Yoo, Donghyun Cho, Kyoungwon Jang, Sanghun Shin, Martin Carolan, Michael Lerch, V Perevertaylo, Anatoly Rosenfeld

Michael L.F. Lerch

In radiotherapy, interest in real-time dosimetry stems from the desire to monitor the dose delivered to the target volume and the surrounding normal tissue to enable clinicians to track the progress of the treatment, and prevent surrounding tissue from receiving too much radiation dose. In this study, the dosimetric performance of the new MOSkin dosimeter and a Bicron BCF-20 scintillating fiber was compared to depth dose measurements taken with a Farmer-type ionization chamber. The performance of the MOSkin and BCF-20 detectors in the build-up region of the depth dose curve, where the dose gradient is steep, is also compared to …

Evaluation Of A Thin Microstrip Detector For High Spatial Resolution Dosimetry, J Kalliopuska, Ashley Cullen, Michael Lerch, Marco Petasecca, M Santala, Anatoly Rosenfeld

Michael L.F. Lerch

VTT and Aalto University have supplied thin microstrip detector prototypes to CMRP for evaluation for the high spatial resolution dosimetry. The evaluation for dosimetry in microbeam radiation therapy (MRT) was done in a synchrotron microbeam at ESRF, France. Measurements studied a response of a single strip on the synchrotron microbeam in face-on and edge-on modes using CMRP designed and developed readout electronics for a parallel readout of single strips. Measurements were done in a passive mode without bias voltage and the detector was scanned through an array of intensive planar microbeams with the nominal width of 50 μm. The face-on …

Characterisation Of Delta E-E Particle Telescope Using The Ansto Heavy Ion Microprobe, Andrew Wroe, Dale Prokopovich, Michael Lerch, Anatoly Rosenfeld, David Cohen, Mihail Ionescu, Iwan Cornelius, Rainer Siegele, A Fazzi, S Agosteo, A Pola, Mark Reinhard

Michael L.F. Lerch

No abstract provided.

Urethral Spectroscopic Alarm (Usa) Probe For Prostate Implants, Anatoly Rosenfeld, Dean Cutajar, Michael Lerch, George Takacs, J Bucci, L Duggan, M Zaider, M Zelefsky, Gil'ad Cohen

Michael L.F. Lerch

Urethral Spectroscopic Alarm (USA) Probe for Prostate Implants 1A.B. Rosenfeld, 1D.L. Cutajar, 1M.L.F. Lerch, 1G.J. Takacs, 2J.A. Bucci, 2L.J. Duggan, 3M. Zaider, 4M. Zelefsky and 3G.N. Cohen 1Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia, 2Institute for Prostate Cancer, St. George Cancer Care Centre, Kogarah, Australia, 3Department of Medical Physics and 4Department of Radiation Oncology, MSKCC, New York, NY Purpose: Prostate implants are associated with excellent biochemical outcome; however, their benefit in terms of overall survival remains unknown. For many patients with early, localized prostate cancer the decision to undergo a treatment of questionable benefit yet because of …

Modelling The Readout Performance Of A New Silicon Photodetector For Use In Pet, Michael Lerch, Philip Simmonds, Robert Ward, Tony Young, George Takacs, Anatoly Rosenfeld, V L Perevertaylo, Steven Meikle

Michael L.F. Lerch

No abstract provided.

Evaluation Of Pixellated, Back-Sided Planar Photodetectors For High-Resolution Imaging Instrumentation, Mark Safavi-Naeini, Michael Lerch, Marco Petasecca, Giorgio Pignatel, Mark Reinhard, Anatoly Rosenfeld

Michael L.F. Lerch

Future generations of solid-state high-energy gamma imaging cameras require pixellated semiconductor photodetectors with the greatest possible detection efficiency. In this paper, a new type of planar silicon PIN photodiode is presented, in which both p+ and n+ electrodes are located on the same side of the device. The design offers highly efficient optical coupling between the backside and scintillator, providing a fill factor of close to 100%. The performance of this detector is modelled using the ISE-TCAD simulator and its electrical and spectroscopic characteristics are experimentally investigated for the case of direct interaction of ionising radiation and also with an …

Solid State Diode - Ionization Chamber Method For Measuring Out-Of-Field Neutron Dose In Proton Therapy, Amy Ziebell, B Clasie, Andrew Wroe, Reinhard Schulte, Mark Reinhard, Stephen Dowdell, Michael Lerch, Marco Petasecca, V Perevertaylo, Oleg Zinets, Igor Anokhin, Anatoly Rosenfeld

Michael L.F. Lerch

In proton therapy neutrons are introduced to out-of-field regions inside the patient. Clinicians would like to know the absorbed dose being deposited by neutrons separately to that from protons, so as to be able to directly apply their own dose equivalent weighting factors based on their opinion of the biological risk posed by neutrons in this region. The purpose of this study is to investigate a novel approach to experimentally separating the proton and neutron contributions to the absorbed dose in out-of-field regions. The method pairs specially designed silicon PIN diodes with a standard clinical ionization chamber. The sensitivity of …

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 …

Measurement Of Rectal Dose During Hdr Brachytherapy Using The New Moskin Dosimeter, Ian Kwan, Andrew Howie, Michael Lerch, Bong Soo Lee, Yaw Sinn Chin, Joseph Bucci, V Perevertaylo, Anatoly Rosenfeld

Michael L.F. Lerch

In HDR prostate brachytherapy, post-treatment complications occur due to overdosing the rectum wall and urethra. An area of concern regarding treatment is related to how the rectal wall dose is calculated using treatment planning systems. Treatment planning systems can calculate the dose delivered to the rectal wall, assuming that the rectum is filled with water equivalent material. This assumption is not always correct, as the rectum is emptied before treatment begins. The aim of this research is to quantify the difference in the dose measured in an ‘empty’ rectal phantom, and in a rectal phantom filled with water equivalent material. …

Brachyview: A Novel In-Body Imaging System For Prostate Brachytherapy, Kevin Loo, Marco Petasecca, Mitra Safavi, Michael Lerch, Zhangbo Han, Jan Jakubek, Stanislav Pospisil, Steven Meikle, Marco Zaider, Joseph Bucci, Anatoly Rosenfeld

Michael L.F. Lerch

The dosimetric quality of seed implants is a crucial part of the prostate brachytherapy treatment procedure. Incorrect seed placement during or after deployment leads to both short and long term complications, including urethral and rectal toxicity. The BrachyView system is a fast intraoperative planning system, providing real-time dosimetric information by acting as an in-body gamma camera. It incorporates three tiled Medipix2 pixellated detectors coupled to a multi-pinhole collimator. Three-dimensional reconstructed images from multiple planar images are used to determine the seed placement in real time. The seed image, when fused with the ultrasound dataset, provides both anatomical and dosimetric information …

Impact Damage On A Thin Glass Plate With A Thin Polycarbonate Backing, Wenke Hu, Yenan Wang, Jian Yu, Chian-Fong Yen, Florin Bobaru

Florin Bobaru Ph.D.

We present experimental and computational results for the impact of a spherical projectile on a thin glass plate with a thin polycarbonate backing plate, restrained in a metal frame, or in the absence of the frame. We analyze the dependence of the damage patterns in the glass plate on the increasing impact velocities, from 61 m/s to 200 m/s. Experimental results are compared with those from peridynamic simulations of a simplified model. The main fracture patterns observed experimentally are captured by the peridynamic model for each of the three projectile velocities tested. More accurate implementation of the actual boundary conditions …

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.

A Comparison Of Gasification Phenomena Among Raw Biomass, Torrefied Biomass And Coal In An Entrained-Flow Reactor, Wei-Hsin Chen

Wei-Hsin Chen

Carbon Dioxide Capture By Single Droplet Using Selexol, Rectisol And Water As Absorbents: A Theoretical Approach, Wei-Hsin Chen

Wei-Hsin Chen

No abstract provided.

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

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

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.