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2013

Impact

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Articles 1 - 30 of 32

Full-Text Articles in Engineering

Impact Of Wind Generator Control Strategies On Flicker Emission In Distribution Networks, Lasantha Meegahapola, Sarath Perera Dec 2013

Impact Of Wind Generator Control Strategies On Flicker Emission In Distribution Networks, Lasantha Meegahapola, Sarath Perera

Dr Lasantha G Meegahapola

Renewable power generators are increasingly being integrated to electricity networks to achieve future renewable energy targets in power generation. In particular, wind power generation has already reported substantial penetration levels in electricity networks. Traditionally, flicker phenomenon is considered to be one of the power quality issues in power distribution networks due to fluctuating consumer loads connected to the network. Large-scale integration of wind power generators may create significant voltage fluctuations in distribution feeders due to stochastic and intermittent nature of the wind resources. This study aims to investigate and characterize the flicker emission under different control strategies for DFIG based …


Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler Dec 2013

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. …


Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn Dec 2013

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 …


Investigation Of Composite Patch Performance Under Low-Velocity Impact Loading, Geoffrey Roy Goodmiller Dec 2013

Investigation Of Composite Patch Performance Under Low-Velocity Impact Loading, Geoffrey Roy Goodmiller

Masters Theses

Bonded fiber composite repair on damaged metal structures can be an effective method to restore load carrying capacity or increase damage resistance. Low velocity impacts can cause barely visible damage to the interior structure of laminated composites. Delamination between plies is of particular concern in these composites. Impacts may also create disbonds between the patch and metal substrate. A building-block approach was suggested to model impact damage to composite patches. Composite, adhesive, and metal substrate damage models were separately validated and then combined. Cohesive Zone theory modeled interlaminar composite damage and adhesive damage. Hashin failure criteria with energy dissipation based …


Impact Damage On A Thin Glass Plate With A Thin Polycarbonate Backing, Wenke Hu, Yenan Wang, Jian Yu, Chian-Fong Yen, Florin Bobaru Nov 2013

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 …


Impact Of Chemical Cleaning On The Nanofiltration Of Pharmaceutically Active Compounds (Phacs): The Role Of Cleaning Temperature, Alexander Simon, William E. Price, Long D. Nghiem Oct 2013

Impact Of Chemical Cleaning On The Nanofiltration Of Pharmaceutically Active Compounds (Phacs): The Role Of Cleaning Temperature, Alexander Simon, William E. Price, Long D. Nghiem

William E. Price

This study investigated the impact of chemical cleaning on the physicochemical properties of a nanofiltration membrane and its subsequent separation efficiency of inorganic salts and two pharmaceutically active compounds (PhACs), sulfamethoxazole and carbamazepine. Chemical cleaning was simulated by immersing virgin membrane samples in aqueous citric acid, sodium hydroxide (NaOH), ethylenediaminetetraacetic-acid (EDTA) and sodium dodecyl sulphate (SDS) at various temperatures for 18 h. The cleaning temperature did not exert any discernible impact on the surface charge of the NF270 membrane selected in this study. However, high cleaning temperatures were shown to either amplify or reduce the impact of chemical cleaning on …


Dynamic Testing Of Tekseal High Yield Grout To Provide An Orepass Plug Designed For Impact, I V. S Mutton, Alexander Remennikov, D Pateman Oct 2013

Dynamic Testing Of Tekseal High Yield Grout To Provide An Orepass Plug Designed For Impact, I V. S Mutton, Alexander Remennikov, D Pateman

Alex Remennikov

Significant wear in orepasses particularly in the brow and chute areas is proportional to the tonnage throughput with increased wear associated with running orepasses empty. During planned shutdowns it may be necessary to isolate maintenance crews from objects falling from orepasses. In the last 15 years grout orepass plugs that can later be easily removed have been poured above chute maintenance areas. These provide protection from high energy impact and isolating workers from the hazard. Construction and removal methods will be briefly explained. Since it is not feasible to investigate the problem of orepass plug impact response using full-scale experimental …


Response Of Rigid Polyurethane Foam-Filled Steel Hollow Columns Under Low Velocity Impact, Alexander Remennikov, Brian Uy, Kong Sih Ying Oct 2013

Response Of Rigid Polyurethane Foam-Filled Steel Hollow Columns Under Low Velocity Impact, Alexander Remennikov, Brian Uy, Kong Sih Ying

Alex Remennikov

This paper presents the results of experimental investigations on rigid polyurethane foam-filled steel hollow columns under dynamic loading conditions.


The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy Oct 2013

The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy

Alex Remennikov

In conventional steel-concrete-steel (SCS) construction, the external steel plates are connected to the concrete infill by welded shear stud connectors. This paper describes a programme of experimental and numerical investigations on reduced-scale non-composite SCS panels with axially restrained connections. The experimental results have demonstrated that the non-composite SCS panels are capable of developing enhanced load-carrying capacity through the tensile membrane resistance of the steel faceplates. This type of construction was found to exhibit highly ductile response and be able to sustain large end rotations of up to 18° without collapse. High fidelity finite element models for SCS panels under impact …


Simulation Of The Reinforced Concrete Slabs Under Impact Loading, Faham Tahmasebinia, Alexander Remennikov Oct 2013

Simulation Of The Reinforced Concrete Slabs Under Impact Loading, Faham Tahmasebinia, Alexander Remennikov

Alex Remennikov

Many older structures were designed for static loads but more recently there has been a growing awareness that some must be designed to resist both dynamic impact and static loads. An accidental impact load can be caused by mishaps in industry as well as accidents stemming from transportation or man-made disasters. There are number of ways of predicting how an impact load will affect a concrete slab, some of which may be impractical or expensive but because there have been significant developments in technology, numerical techniques rather than experimental approaches have become popular methods for developing detailed responses Therefore, to …


Development And Assessment Of An Impact Apparatus And High-Speed Camera Motion Tracking System To Quantify The Effect Of Static Muscle Loads On Fracture Threshold Measures In The Distal Radius, Jacob M. Reeves Aug 2013

Development And Assessment Of An Impact Apparatus And High-Speed Camera Motion Tracking System To Quantify The Effect Of Static Muscle Loads On Fracture Threshold Measures In The Distal Radius, Jacob M. Reeves

Electronic Thesis and Dissertation Repository

Distal radius fractures are prevalent, debilitating, and costly. This thesis conducts an in vitro investigation of these injuries, examining the role of static muscle loading on fracture threshold measures (i.e., force, impulse, energy). Initially, an impact apparatus and custom LabVIEW colour-thresholding program were designed and assessed for repeatability and accuracy in quantifying fracture measures and impact kinematics. These tools were then used to test six pairs of cadaveric forearms, with static muscle loads simulated in one specimen from each pair. Distal radius fractures were achieved in 5 pairs, with perilunate dislocations in the remaining pair. None of the …


The Water Entry Of Slender Axisymmetric Bodies: Forces, Trajectories And Acoustics, Kyle Gordon Bodily Jul 2013

The Water Entry Of Slender Axisymmetric Bodies: Forces, Trajectories And Acoustics, Kyle Gordon Bodily

Theses and Dissertations

Free surface water entry of various objects has been studied using high-speed images and image processing techniques for decades. This thesis studies the forces, velocities, and trajectories of slender axisymmetric projectiles using an embedded inertial measurement unit (IMU). Three nose shapes (cone, ogive, and flat) were used in the study. Additionally, the projectiles were tested at vertical and oblique impact angles with different surface conditions. One-half of each projectile was coated down the centerline with a hydrophobic spray, creating a half hydrophobic, half hydrophilic case. The trajectory of this half-and-half case impacting vertically was compared to the trajectory of symmetrically …


Impact Mechanics And High-Energy Absorbing Materials: Review, Pizhong Qiao, Mijia Yang, Florin Bobaru Jul 2013

Impact Mechanics And High-Energy Absorbing Materials: Review, Pizhong Qiao, Mijia Yang, Florin Bobaru

Florin Bobaru Ph.D.

In this paper a review of impact mechanics and high-energy absorbing materials is presented. We review different theoretical models (rigid-body dynamics, elastic, shock, and plastic wave propagation, and nonclassical or nonlocal models. and computational methods (finite-element, finite-difference, and mesh-free methods. used in impact mechanics. Some recent developments in numerical simulation of impact (e.g., peridynamics) and new design concepts proposed as high energy absorbing materials (lattice and truss structures, hybrid sandwich composites, metal foams, magnetorheological fluids, porous shape memory alloys. are discussed. Recent studies on experimental evaluation and constitutive modeling of strain rate-dependent polymer matrix composites are also presented. Impact damage …


Studying The Impact Of The Corner Propagation Model On Vanet Routing In Urban Environments, Abhinay Mukunthan, Craig Cooper, Farzad Safaei, D. Franklin, Mehran Abolhasan Jun 2013

Studying The Impact Of The Corner Propagation Model On Vanet Routing In Urban Environments, Abhinay Mukunthan, Craig Cooper, Farzad Safaei, D. Franklin, Mehran Abolhasan

Professor Farzad Safaei

Accurate modelling of the radio channel is often the most difficult aspect of a Vehicular Ad Hoc Network (VANET) simulation due to the large variability present in vehicular terrain. CORNER is a propagation model that calculates path-loss in an urban terrain with a large concentration of buildings, based on the position of the transmitter and receiver on a street map. This paper proposes additions to the CORNER propagation model to take selective multi-path fading into account and investigates the performance of the GPSR routing protocol under the CORNER propagation model in a realistic city environment.


The Impact Of Different Rotation Patterns On The Sampling Variance Of Seasonally Adjusted And Trend Estimates, Craig Mclaren, David Steel Jun 2013

The Impact Of Different Rotation Patterns On The Sampling Variance Of Seasonally Adjusted And Trend Estimates, Craig Mclaren, David Steel

Professor David Steel

Many economic and social time series are based on sample surveys which have complex sample designs. The sample design affects the properties of the time series. In particular, the overlap of the sample from period to period affects the variability of the time series of survey estimates, and the seasonally adjusted and trend estimates produced from them. The Census X11 and X11ARIMA packages are commonly used to produce seasonally adjusted estimates and can also be used to produce estimates of trend. This paper considers the implications of different overlap patterns on the sampling variance of seasonally adjusted and trend estimates …


Impact Of Sintering Temperature On The Physical Properties Of The Superconducting Ferromagnet: Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou Jun 2013

Impact Of Sintering Temperature On The Physical Properties Of The Superconducting Ferromagnet: Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou

Shi Xue Dou

We report the influence of the sintering temperature on the electromagnetic behavior for the RuSr2Eu1.5Ce0.5Cu2O10 material, in which superconductivity and ferromagnetism coexist. The inadequate heat treatment results in the coexistence of the secondary Ru-1212 phase along with the dominant Ru-1222 phase. The presence of two phases leads to the magnetic superposition of the signals from both phases, which results in the observation of a small peak around 120–130 K. In the pure Ru-1222 no such magnetic anomaly is observed. In addition, the impure samples exhibit a double step superconductivity transition. In the normal state, these impure samples exhibit a semiconductinglike …


The Fundamentals Of A Course On The Environmental Impacts Of Ships, Patricia A. Coker May 2013

The Fundamentals Of A Course On The Environmental Impacts Of Ships, Patricia A. Coker

University of New Orleans Theses and Dissertations

No abstract provided.


Impact Of Mains Connected Three-Phase Induction Motor Loading Levels On Network Voltage Unbalance Attenuation, Upuli Jayatunga, Sarath Perera, Philip Ciufo Feb 2013

Impact Of Mains Connected Three-Phase Induction Motor Loading Levels On Network Voltage Unbalance Attenuation, Upuli Jayatunga, Sarath Perera, Philip Ciufo

Dr Philip Ciufo

Voltage unbalance (VU) in power systems should be managed in a systematic manner in order to minimise its adverse effects on both customer equipment and supply utilities. It is a well known fact that three-phase induction motor performance can be significantly affected in the presence of supply voltage unbalance. It is also known that three-phase induction motors can help to reduce pre-existing network voltage unbalance levels. Recently undertaken research aligned with IEC/TR 61000-3-13:2008 Technical Report on voltage unbalance management (emission allocation and emission assessment) have quantified the contribution made by induction motors to the net voltage unbalance at a point …


A Damage-Trap Interfacial Design To Improve Impact Resistance Of Polymers, Md Shariful Islam Jan 2013

A Damage-Trap Interfacial Design To Improve Impact Resistance Of Polymers, Md Shariful Islam

Open Access Theses & Dissertations

Polymer materials such as Polycarbonate (PC), Polymethyl methacrylate (PMMA) have numerous applications in transparent armor which includes body and face shield, helmet, windows of the armored vehicle etc. The most challenging part of these applications is to ensure the safety of the people. These materials are often subjected to impact loading, so it is important to study the failure of these materials under impact loading. An experimental study has been made to investigate the impact damage in transparent layered materials. Impact experiments were carried out on various monolithic specimens and layered specimens for both two types of materials at different …


A Model Of The Effects Of Authority On Consensus Formation In Adaptive Networks: Impact On Network Topology And Robustness, Brenton J. Prettejohn, Matthew J. Berryman, Mark D. Mcdonnell Jan 2013

A Model Of The Effects Of Authority On Consensus Formation In Adaptive Networks: Impact On Network Topology And Robustness, Brenton J. Prettejohn, Matthew J. Berryman, Mark D. Mcdonnell

Faculty of Engineering and Information Sciences - Papers: Part A

Opinions of individuals in real social networks are arguably strongly influenced by external determinants, such as the opinions of those perceived to have the highest levels of authority. In order to model this, we have extended an existing model of consensus formation in an adaptive network by the introduction of a parameter representing each agent's level of 'authority' based on their opinion relative to the overall opinion distribution. We found that introducing this model, along with a randomly varying opinion convergence factor, significantly impacts the final state of converged opinions and the number of interactions required to reach that state. …


The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy Jan 2013

The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy

Faculty of Engineering and Information Sciences - Papers: Part A

In conventional steel-concrete-steel (SCS) construction, the external steel plates are connected to the concrete infill by welded shear stud connectors. This paper describes a programme of experimental and numerical investigations on reduced-scale non-composite SCS panels with axially restrained connections. The experimental results have demonstrated that the non-composite SCS panels are capable of developing enhanced load-carrying capacity through the tensile membrane resistance of the steel faceplates. This type of construction was found to exhibit highly ductile response and be able to sustain large end rotations of up to 18° without collapse. High fidelity finite element models for SCS panels under impact …


Dynamic Testing Of Tekseal High Yield Grout To Provide An Orepass Plug Designed For Impact, I V. S Mutton, Alexander Remennikov, D Pateman Jan 2013

Dynamic Testing Of Tekseal High Yield Grout To Provide An Orepass Plug Designed For Impact, I V. S Mutton, Alexander Remennikov, D Pateman

Faculty of Engineering and Information Sciences - Papers: Part A

Significant wear in orepasses particularly in the brow and chute areas is proportional to the tonnage throughput with increased wear associated with running orepasses empty. During planned shutdowns it may be necessary to isolate maintenance crews from objects falling from orepasses. In the last 15 years grout orepass plugs that can later be easily removed have been poured above chute maintenance areas. These provide protection from high energy impact and isolating workers from the hazard. Construction and removal methods will be briefly explained. Since it is not feasible to investigate the problem of orepass plug impact response using full-scale experimental …


Impact Of Chemical Cleaning On The Nanofiltration Of Pharmaceutically Active Compounds (Phacs): The Role Of Cleaning Temperature, Alexander Simon, William E. Price, Long D. Nghiem Jan 2013

Impact Of Chemical Cleaning On The Nanofiltration Of Pharmaceutically Active Compounds (Phacs): The Role Of Cleaning Temperature, Alexander Simon, William E. Price, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

This study investigated the impact of chemical cleaning on the physicochemical properties of a nanofiltration membrane and its subsequent separation efficiency of inorganic salts and two pharmaceutically active compounds (PhACs), sulfamethoxazole and carbamazepine. Chemical cleaning was simulated by immersing virgin membrane samples in aqueous citric acid, sodium hydroxide (NaOH), ethylenediaminetetraacetic-acid (EDTA) and sodium dodecyl sulphate (SDS) at various temperatures for 18 h. The cleaning temperature did not exert any discernible impact on the surface charge of the NF270 membrane selected in this study. However, high cleaning temperatures were shown to either amplify or reduce the impact of chemical cleaning on …


Impact Of Patient Rotational Errors On Target And Critical Structure Dose In Imrt: A 3d Simulation Study, S Arumugam, A Xing, P Vial, A Scotti, R Stirton, G Goozee, Lois Holloway Jan 2013

Impact Of Patient Rotational Errors On Target And Critical Structure Dose In Imrt: A 3d Simulation Study, S Arumugam, A Xing, P Vial, A Scotti, R Stirton, G Goozee, Lois Holloway

Faculty of Engineering and Information Sciences - Papers: Part A

The impact of 3D rotational errors in patient positioning on dose delivered target volumes and critical structures in IMRT was studied. Patient rotational errors ranging from -30 to +30 was introduced to IMRT treatment plans of pelvis, head and neck and brain treatment sites and the impact of rotational error on DVH metrics was assessed. The magnitude of impact of rotational error on the error in dose delivered to the target volume and critical structures depends on the location of the structures from plan isocentre. In studied plans, a maximum percentage difference of up to -9.8(1s=13.4) % in D95 to …


Enhancing Impact Fracture Toughness And Tensile Properties Of A Microalloyed Cast Steel By Hot Forging And Post-Forging Heat Treatment Processes, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee Jan 2013

Enhancing Impact Fracture Toughness And Tensile Properties Of A Microalloyed Cast Steel By Hot Forging And Post-Forging Heat Treatment Processes, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee

Faculty of Engineering and Information Sciences - Papers: Part A

In the present work, the effects of hot forging and post-forging heat treatment on the impact fracture toughness and tensile properties of a microalloyed cast steel were investigated. Mechanical tests were used to evaluate the room temperature impact fracture toughness and tensile properties of the steel. The resulting microstructures were analysed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The extraction replica technology was used to investigate the characterisation of complex precipitates formed during heat treatment. The obtained results showed that the coarse-grained microstructure of the forged specimen was significantly refined after post-forging heat treatment. …


Impact Of Humic Acid Fouling On Membrane Performance And Transport Of Pharmaceutically Active Compounds In Forward Osmosis, Ming Xie, Long D. Nghiem, William E. Price, Menachem Elimelech Jan 2013

Impact Of Humic Acid Fouling On Membrane Performance And Transport Of Pharmaceutically Active Compounds In Forward Osmosis, Ming Xie, Long D. Nghiem, William E. Price, Menachem Elimelech

Faculty of Engineering and Information Sciences - Papers: Part A

The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) - namely carbamazepine and sulfamethoxazole - in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the …


Impact Of The Mlc On The Mri Field Distortion Of A Prototype Mri-Linac, Stefan Kolling, Brad Oborn, Paul Keall Jan 2013

Impact Of The Mlc On The Mri Field Distortion Of A Prototype Mri-Linac, Stefan Kolling, Brad Oborn, Paul Keall

Faculty of Engineering and Information Sciences - Papers: Part A

Purpose: To cope with intrafraction tumor motion, integrated MRI-linac systems for real-time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state-of-the-art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality. Methods: Results: Conclusions: This work shows that the MRI field distortions caused by the MLC cannot be ignored and must be thoroughly investigated for any MRI-linac system. The numeric distortion values obtained for our1.0T magnet may vary for other magnet …


Impact Of Capacity Value Of Renewable Energy Resources On Raps System Energy Management, Y Tan, Kashem Muttaqi, Lasantha Meegahapola Jan 2013

Impact Of Capacity Value Of Renewable Energy Resources On Raps System Energy Management, Y Tan, Kashem Muttaqi, Lasantha Meegahapola

Faculty of Engineering and Information Sciences - Papers: Part A

Renewable energy resources are widely being utilised in remote area power supply (RAPS) systems. The capacity value of renewable energy resources in a RAPS system indicates the ability of renewable energy resources to serve the load demand in the RAPS systems. In this paper, the impact of capacity value of renewable resources on energy management of a RAPS system, while maintaining system reliability, is investigated. It is revealed that capacity value of renewable energy resources has direct influence on RAPS system energy management. By utilising storage in conjunction with renewable energy resources, the RAPS system can cater load demand while …


On The Residual Energy Toughness Of Prestressed Concrete Sleepers In Railway Track Structures Subjected To Repeated Impact Loads, Sakdirat Kaewunruen, Alexander Remennikov Jan 2013

On The Residual Energy Toughness Of Prestressed Concrete Sleepers In Railway Track Structures Subjected To Repeated Impact Loads, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering and Information Sciences - Papers: Part A

Installed as the crosstie beam support in railway track systems, the prestressed concrete sleepers (or railroad ties) are designed in order to carry and transfer the wheel loads from the rails to the ground. It is nowadays best known that railway tracks are subject to the impact loading conditions, which are attributable to the train operations with either wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration, as well as there exists the potential of repeated load experience during the design life of the prestressed concrete sleepers. These …


Incremental Service Level Agreements Violation Handling With Time Impact Analysis, Azlan Ismail, Jun Yan, Jun Shen Jan 2013

Incremental Service Level Agreements Violation Handling With Time Impact Analysis, Azlan Ismail, Jun Yan, Jun Shen

Faculty of Engineering and Information Sciences - Papers: Part A

This research addresses a critical issue of service level agreement (SLA) violation handling, i.e., time constraint violation related to service-based systems (SBS). Whenever an SLA violation occurs to a service, it can potentially impact dependent services, leading to unreliable SBS. Therefore, an SLA violation handling support is much required to produce a robust and adaptive SBS. There are several approaches to realizing exceptions and faults handling support for SBS, focusing on the detection stage, the analysis stage, and the resolution stage. However, the current works have not considered the handling strategy that takes the impact information into account to reduce …