Engineering Commons^™

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 …

Dosimetry Of Intensive Synchrotron Microbeams, Michael Lerch, Marco Petasecca, A Cullen, A Hamad, H Requardt, E Brauer-Krisch, A Bravin, V Perevertaylo, Anatoly Rosenfeld

Michael L.F. Lerch

Intensive synchrotron X-ray microbeams form an integral part of microbeam radiation therapy (MRT). MRT is a novel radiation medicine modality being developed for inoperable and otherwise untreatable brain tumours. The extremely high dose rate (∼20 kGy/s), laterally fractionated radiation field and steep dose gradients utilized in this therapy make real-time dosimetry a significant challenge. In order for this treatment to advance to the clinical trial stage of development real-time dosimetry systems must be developed. This paper demonstrates the capabilities of a new dosimetry system based on an epitaxial silicon detector. The system combines high spatial resolution and real-time readout and …

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. …

Verification Of The Plan Dosimetry For High Dose Rate Brachytherapy Using Metal-Oxide-Semiconductor Field Effect Transistor Detectors, Zhen-Yu Qi, Xiao-Wu Deng, Shao-Min Huang, Jie Lu, Michael Lerch, Dean Cutajar, Anatoly Rosenfeld

Michael L.F. Lerch

The feasibility of a recently designed metal–oxide–semiconductor field effect transistor (MOSFET) dosimetry system for dose verification of high dose rate (HDR) brachytherapy treatment planning was investigated. MOSFET detectors were calibrated with a 0.6 cm3 NE-2571 Farmer-type ionization chamber in water. Key characteristics of the MOSFET detectors, such as the energy dependence, that will affect phantom measurements with HDR 192Ir sources were measured. The MOSFET detector was then applied to verify the dosimetric accuracy of HDR brachytherapy treatments in a custom-made water phantom. Three MOSFET detectors were calibrated independently, with the calibration factors ranging from 0.187 to 0.215 cGy∕mV. A distance …

Miniature Semiconductor Detectors For In Vivo Dosimetry, Anatoly Rosenfeld, Dean Cutajar, Michael Lerch, George Takacs, Iwan Cornelius, M Yudelev, M Zaider

Michael L.F. Lerch

Silicon mini-semiconductor detectors are found in wide applications for in vivo personal dosimetry and dosimetry and microdosimetry of different radiation oncology modalities. These applications are based on integral and spectroscopy modes of metal oxide semiconductor field effect transistor and silicon p–n junction detectors. The advantages and limitations of each are discussed.

Monte Carlo Modelling Of A Silicon Strip Detector For Microbeam Radiation Therapy, Ashley Cullen, Michael Lerch, Marco Petasecca, Anatoly Rosenfeld

Michael L.F. Lerch

Microbeam radiation therapy is an experimental technique utilising synchrotron X-rays collimated into a planar array of microbeams. Due to the complex structure of the radiation field and high dose rate, this introduces dosimetric challenges. Current dosimetric methods are inadequate in that they lack either real-time readout, or high spatial resolution. A detector system, consisting of the Silicon Multi-Strip Detector and associated readout system was developed at the University of Wollongong. This system performs online, real-time dosimetry, and is designed for placement upstream of the patient as a transmission detector. The interaction of synchrotron radiation with this detector, both in terms …

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 …

Skin Dosimetry With New Mosfet Detectors, Ian Kwan, Anatoly Rosenfeld, Zhen Yu Qi, Dean Wilkinson, Michael Lerch, Dean Cutajar, Mark Safavi-Naeini, Martin Butson, J Bucci, Y Chin, V Perevertaylo

Michael L.F. Lerch

The MOSkin, a new MOSFET-based detector designed by the Centre for Radiation Physics, was engineered to provide accurate measurements of skin doses in radiotherapy and personal monitoring. The International Commission on Radiological Protection (ICRP) estimates the radiosensitive basal layer to be at an average depth of 0.070 mm. Current commercially available MOSFETs utilize an epoxy bubble encapsulation, making measurements at equivalent depths of 0.070mm difficult. The MOSkin utilizes a novel packaging design that allows the measurement of doses at this equivalent depth. The MOSkin has shown excellent agreement with the Attix chamber for surface measurements in a 6MV photon beam …

Independent Quality Assurance Of A Helical Tomotherapy Machine Using The Dose Magnifying Glass, Jeannie Wong, Nick Hardcastle, Wolfgang Tome, A Bayliss, R Tolakanahalli, Michael Lerch, Marco Petasecca, Martin Carolan, Peter Metcalfe, Anatoly Rosenfeld

Michael L.F. Lerch

Purpose: Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenience lacks the rigor of a machine-independent QA process. Methods: In this article, a Si strip detector, known as the Dose Magnifying Glass (DMG), was used to perform machine-independent QA measurements of the multileaf collimator alignment, leaf open time threshold, and leaf fluence output factor (LFOF). Results: The DMG measurements showed good agreements …

Development Of A New Detector Module For Use In Positron Emission Tomography, Michael Lerch, Robert Ward, Philip Simmonds, Steven Meikle, Anatoly Rosenfeld, George Takacs, V Pervertailo, G Taylor

Michael L.F. Lerch

No abstract provided.

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

Interaction Diagrams For Frp Wrapped Circular Hollow Columns, Veysel Yazici, Muhammad Hadi

Veysel Yazici

No abstract provided.

Testing Frp Confined Columns Under Eccentric Loading, Muhammad Hadi, Veysel Yazici

Veysel Yazici

A number of research studies have shown that the axial load carrying capacity of reinforcedconcrete columns increases substantially when wrapped with FRP. In addition FRP wrappingalso increases the lateral deformation capacity of the columns especially under eccentric loads,thus suggesting that an introduced slenderness effect has to be considered when columns arewrappedwith FRP sheets. Six circular RC columns were cast and divided into two groups whichwere tested under 25mm and 50mm eccentricity. Both groups had an unwrapped column, athree layer FRPwrapped column in the hoop direction, and a column which had discrete verticalFRP strips attached to its surface before a three …

Increasing The Flexural Stiffness Of Frp Wrapped Reinforced Concrete Columns, Muhammad Hadi, Veysel Yazici

Veysel Yazici

Axial load carrying capacity of reinforced concrete columns increase substantially after FRP wrapping. However, the same method also increases the lateral deformation capacity 61the columns especially under eccentric loads implying that secondary moments have to be considered when column are wrapped with FRP sheets under high level of axial loads. In this experimental study, six circular RC columns were cast and divided into two groups which were tested under 25 mm and 50 mm eccentric axial loads. Both groups had an unwrapped RC column, a three layers FRP wrapped column in the hoop direction, and a column which had discrete …

Stabilisation Of Expansive Clays Using Granulated Blast Furnace Slag (Gbfs) And Gbfs-Cement, Erdal Cokca, Veysel Yazici, Vehbi Ozaydin

Veysel Yazici

Expansive clays undergo swelling when subjected to water. This can cause damage, especially to light weight structures, water conveyance canals, lined reservoirs, highways, and airport runways unless appropriate measures are taken. In this study, granulated blast furnace slag (GBFS) and GBFS-cement (GBFSC) were utilized to overcome or to limit the expansion of an artificially prepared expansive soil sample (sample A). GBFS and GBFSC were added to sample A in proportions of 5–25% by weight. The effects of these stabilizers on grain size distribution, Atterberg limits, swelling percentage and rate of swell of soil samples were determined. GBFS and GBFSC were …

Axial Load-Bending Moment Diagrams Of Carbon Frp Wrapped Hollow Core Reinforced Concrete Columns, Veysel Yazici, Muhammad Hadi

Veysel Yazici

Hollow core reinforced concrete columns are generally preferred in use to decrease the cost and weight/stiffnesss ratio of members, such as bridge columns and piles. With a simplified stress state assumption, strengthening a hollow core reinforced concrete column with fiber-reinforced polymer (FRP) wrapping provides a biaxial confinement to the concrete, which leads to a need of defining the effect of FRP wrapping on the strength and ductility of the hollow core reinforced concrete columns. In this study, two groups of four hollow core reinforced concrete columns ( 205mmouter diameter, 56mmhollow core diameter, and 925mmheight) were tested under concentric, eccentric (25 …

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.

Hydrogen Permeation And Recovery From H2-N2 Gas Mixtures By Pd Membranes With High Permeance, 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.

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

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

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

Dr Raad Raad

No abstract provided.

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 …

Tandem Gas Metal Arc Welding For Low Distortion Butt Welds, Nathan Larkin, Zengxi Pan, Stephen Van Duin, Mark Callaghan, Huijun Li, John Norrish

zengxi pan

The feasibility of using Tandem Gas Metal Arc Welding (T-GMAW) to produce full penetration butt welds in 5mm ship panel steel plates has been assessed and compared to the current Submerged Arc Welding (SAW) process. Experiments conducted show that the T-GMAW process is feasible and demonstrated a significant improvement over the SAW process in several areas including higher travel speed, a reduction in filler material, significantly lower post weld distortion, and a smaller Heat Affected Zone (HAZ), while maintaining similar microstructure and mechanical properties in the weld metal and HAZ.

Autonomous Blimp Control Using Reinforcement Learning, Yiwei Liu, Zengxi Pan, David Stirling, Fazel Naghdy

zengxi pan

This paper presents a new approach for navigation control of an autonomous blimp using an intelligent reinforcement learning algorithm. Compared to the traditional model based control methods, this control strategy does not require a dynamic model of the blimp, which provides huge advantage in many practical situations where the blimp system model is either hard to acquire or too complicated to apply. As the blimp will acquire a range of the pilot skills through a learning and rewarding mechanism during actual navigation trials, it can automatically account for the environmental changes during the navigation. The simulation data generated from a …