Social and Behavioral Sciences Commons^™

Nonlinear Dynamical Behavior Of Axially Accelerating Beams: Three-Dimensional Analysis, Mergen H. Ghayesh, Hamed Farokhi

Faculty of Engineering and Information Sciences - Papers: Part A

The three-dimensional (3D) nonlinear dynamics of an axially accelerating beam is examined numerically taking into account all of the longitudinal, transverse, and lateral displacements and inertia. Hamilton's principle is employed in order to derive the nonlinear partial differential equations governing the longitudinal, transverse, and lateral motions. These equations are transformed into a set of nonlinear ordinary differential equations by means of the Galerkin discretization technique. The nonlinear global dynamics of the system is then examined by time-integrating the discretized equations of motion. The results are presented in the form of bifurcation diagrams of Poincare maps, time histories, phase-plane portraits, Poincare …

Analytic Performance Model For State-Based Mac Layer Cooperative Retransmission Protocols, Brett Hagelstein, Mehran Abolhasan, Daniel R. Franklin, Farzad Safaei, Wei Ni

Faculty of Engineering and Information Sciences - Papers: Part A

Cooperative retransmission can significantly improve link reliability over lossy and time-varying wireless links. However, comparing retransmission protocols is challenging, and generally requires simplistic assumptions specific to each protocol. In this paper, we develop a general model to evaluate cooperative retransmission protocols with distributed, slot-based contention algorithms. Specifically, we propose to calculate the relay time-out probabilities at a MAC time-slot scale, formulate retransmission outcomes as functions of the time-out probabilities, and derive the probability of a retransmission process for every data frame. We also propose a Markov extension of our model to characterise the dependency between retransmissions of multiple frames. This …

Nano-Enhanced Phase Change Materials For Improved Building Performance, Zhenjun Ma, Wenye Lin, Mohammed I. Sohel

Faculty of Engineering and Information Sciences - Papers: Part A

Nano-enhanced phase change materials (PCMs) have attracted increasing attention to address one of the key barriers (i.e. low thermal conductivity) to the wide adoption of PCMs in many industrial applications. This paper discusses the generic problem and key issues associated with appropriately using this new class of materials in buildings for effective thermal management and improved energy performance. An overview on major recent development and application of nano-enhanced PCMs as thermal energy storage media is provided. A case study based on a PCM ceiling ventilation system integrated with solar photovoltaic thermal (PVT) collectors is then performed to evaluate the potential …

New Configuration Of Transverse Reinforcement For Improved Seismic Resistance Of Rectangular Rc Columns: Concept And Axial Compressive Behavior, D H. Jing, T Yu, X D. Liu

Faculty of Engineering and Information Sciences - Papers: Part A

Columns are considered to be critical members of moment-resisting structural systems. In seismically active regions, it is important to improve the ductile deformation capacity and energy dissipation capacity of columns so that the entire structure can endure severe ground motion and dissipate a considerable amount of seismic energy. Against this background, this paper presents the idea of a new transverse reinforcement configuration (TRC) for improved seismic performance of rectangular (including square) reinforced concrete (RC) columns. The novel features of the new TRC compared to conventional TRCs using rectangular hoops and cross ties mainly include the use of additional small circular …

Hot Enough For You? A Spatial Exploratory And Inferential Analysis Of North American Climate-Change Projections, Noel A. Cressie, Emily L. Kang

Faculty of Engineering and Information Sciences - Papers: Part A

Climate models have become the primary tools for scientists to project climate-change into the future and to understand its potential impact. Continental-scale General Circulation Models (GCMs) oversimplify the regional climate processes and geophysical features such as topography and land cover. The consequences of local/regional climate change are particularly relevant to natural resource management and environmental-policy decisions, for which Regional Climate Models (RCMs) have been developed. RCMs simulate, for example, three-hourly "weather" over long time periods, from which long-run averages (e.g., over 30 years) are commonly computed to estimate a region's future climate. With anthropogenic forcings incorporated, RCMs provide a means …

Fault-Tolerant Control Of Electric Vehicles With In-Wheel Motors Using Actuator-Grouping Sliding Mode Controllers, Boyuan Li, Haiping Du, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

Although electric vehicles with in-wheel motors have been regarded as one of the promising vehicle architectures in recent years, the probability of in-wheel motor fault is still a crucial issue due to the system complexity and large number of control actuators. In this study, a modified sliding mode control (SMC) is applied to achieve fault-tolerant control of electric vehicles with four-wheel-independent-steering (4WIS) and four-wheel-independent-driving (4WID). Unlike in traditional SMC, in this approach the steering geometry is re-arranged according to the location of faulty wheels in the modified SMC. Three SMC control laws for longitudinal velocity control, lateral velocity control and …

Comments On "Public Integrity Auditing For Dynamic Data Sharing With Multi-User Modification", Yong Yu, Yannan Li, Jianbing Ni, Guomin Yang, Yi Mu, Willy Susilo

Faculty of Engineering and Information Sciences - Papers: Part A

Recently, a practical public integrity auditing scheme supporting multiuser data modification (IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY, DOI 10.1109/TIFS.2015.2423264) was proposed. Although the protocol was claimed secure, in this paper, we show that the proposal fails to achieve soundness, the most essential property that an auditing scheme should provide. Specifically, we show that a cloud server can collude with a revoked user to deceive a third-party auditor (TPA) that a stored file keeps virgin even when the entire file has been deleted.

Electro-Tactile Feedback System To Enhance Virtual Reality Experience, D S. Pamungkas, K Ward

Faculty of Engineering and Information Sciences - Papers: Part A

Virtual Reality (VR) has been proven to be capable of enabling its users to experience immersive virtual environments and interact with the computer. Most VR applications utilize stereo visual perception, however, stereo visual perception alone is not enough to fully immerse users in VR environments. Haptic feedback technology when applied to VR applications can offer improved immersion and interactivity and can extend the range of sensations experienced by the user. For example, tactile feedback can enable the user to feel an object they touch with their virtual hand or body. To provide tactile feedback in VR applications most researchers construct …

Secure Multiparty Quantum Computation For Summation And Multiplication, Run-Hua Shi, Yi Mu, Hong Zhong, Jie Cui, Shun Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

As a fundamental primitive, Secure Multiparty Summation and Multiplication can be used to build complex secure protocols for other multiparty computations, specially, numerical computations. However, there is still lack of systematical and efficient quantum methods to compute Secure Multiparty Summation and Multiplication. In this paper, we present a novel and efficient quantum approach to securely compute the summation and multiplication of multiparty private inputs, respectively. Compared to classical solutions, our proposed approach can ensure the unconditional security and the perfect privacy protection based on the physical principle of quantum mechanics.

Online Coordinated Voltage Control In Distribution Systems Subjected To Structural Changes And Dg Availability, Dothinka Ranamuka Rallage, Ashish P. Agalgaonkar, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

The responses of multiple DG units and voltage regulating devices such as tap changers and capacitor banks for correcting the voltage may lead to operational conflicts and oscillatory transients, where distribution systems are subjected to network reconfiguration and changes in availability of the DG units. Therefore, coordinated voltage control is required to minimize control interactions while accounting for the impact of structural changes associated with the network. This paper proposes a strategy for coordinating the operation of multiple voltage regulating devices and DG units in medium voltage (MV) distribution systems, under structural changes and DG availability, for effective voltage control. …

A Dual Deformation Mechanism Of Grain Boundary At Different Stress Stages, Liang Zhang, Cheng Lu, Jie Zhang, A Kiet Tieu

Faculty of Engineering and Information Sciences - Papers: Part A

Molecular dynamics (MD) simulation with embedded-atom method (EAM) potential was carried out to study the structure and shear response of an asymmetric tilt grain boundary in copper bicrystal. A non-planar structure with dissociated intrinsic stacking faults was observed in the grain boundary. Simulation results show that this type of structure can significantly increase the ductility of the simulation sample under shear deformation. A dual deformation mechanism of the grain boundary was observed; the grain boundary can be a source of dislocation emission and migrate itself at different stress stages. The result of this study can provide further information to understand …

Strategies For The Development Of Three Dimensional Scaffolds From Piezoelectric Poly(Vinylidene Fluoride), Daniela M. Correia, Clarisse Ribeiro, Vitor Sencadas, L Vikingsson, M Oliver Gasch, J L. Gomez Ribelles, Gabriela Botelho, Senentxu Lanceros-Méndez

Faculty of Engineering and Information Sciences - Papers: Part A

Cell supports based on electroactive materials, that generate electrical signal variations as a response to mechanical deformations and vice-versa, are gaining increasing attention for tissue engineering applications. In particular, poly(vinylidene fluoride), PVDF, has been proven to be suitable for these applications in the form of films and two-dimensional membranes. In this work, several strategies have been implemented in order to develop PVDF three-dimensional scaffolds. Three processing methods, including solvent casting with particulate leaching and three-dimensional nylon, and freeze extraction with poly(vinyl alcohol) templates are presented in order to obtain three-dimensional scaffolds with different architectures and interconnected porosity. Further, it is …

Elastomeric And Dynamic Mno2/Cnt Core-Shell Structure Coiled Yarn Supercapacitor, Changsoon Choi, Hyeon Jun Sim, Geoffrey M. Spinks, Xavier Lepró, Ray H. Baughman, Seon Jeong Kim

Faculty of Engineering and Information Sciences - Papers: Part A

Reversibly deformable and highly performing solid-state yarn supercapacitors are obtained using MnO2-deposited microcoiled yarn electrodes. The core(CNT)-shell(MnO2)-structured coiled electrodes achieve high stretchability (37.5%) without the help of elastomeric substrates, minimizing the size of the supercapacitors. Therefore, high specific capacitances of 34.6 F cm−3, 61.25 mF cm−2, and 2.72 mF cm−1 are achieved for coiled supercapacitors without impairing mechanical stretchability or electrochemical cyclability.

Effects Of Surface Roughness On Micro Deep Drawing Of Circular Cups With Consideration Of Size Effects, Liang Luo, Zhengyi Jiang, Dongbin Wei, Kenichi Manabe, Xianming Zhao, Di Wu, Tsuyoshi Furushima

Faculty of Engineering and Information Sciences - Papers: Part A

Surface roughness, compared with tiny sizes of micro products, can be relatively large and has significant influences on micro forming processes and products' quality. In this study, a voronoi finite element model that considers size effects of material was developed. Next the surface roughness information was assigned to this voronoi model through different elemental thickness distributions. Furthermore, springback simulation was conducted for the micro deep drawn circular cups. Simulation results demonstrate that the surface roughness with consideration of size effects has significant influences on the overall springback, the drawability represented by the minimum thickness and products' quality regarding thickness evenness …

Tribological Behavior In Micro-Sheet Hydroforming, Hideki Sato, Kenichi Manabe, Dongbin Wei, Zhengyi Jiang, Sergei Alexandrov

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, the tribological behavior and its size effects in micro-hydromechanical deep drawing (MHDD) are theoretically and experimentally investigated. It is found that a required fluid pressure for hydrodynamic lubrication significantly increases with scaling down micro-scale due to a high sealablity at small relative punch diameter to minimum thickness. Moreover, the opposite tribological size effect from a conventional microforming appears in MHDD in which the fluid medium can be kept in open lubricant pockets (OLPs) by applying a fluid pressure and, the friction coefficient decreases as a specimen size decreases. Thus, MHDD can induce the hydrodynamic lubrication and lubrication …

A Review Of Topologies Of Three-Port Dc-Dc Converters For The Integration Of Renewable Energy And Energy Storage System, Neng Zhang, Danny Sutanto, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

The application of renewable energy such as solar photovoltaic (PV), wind and fuel cells is becoming increasingly popular because of the environmental awareness and advances in technology coupled with decreasing manufacturing cost. Power electronic converters are usually used to convert the power from the renewable sources to match the load demand and grid requirement to improve the dynamic and steady-state characteristics of these green generation systems, to provide the maximum power point tracking (MPPT) control, and to integrate the energy storage system to solve the challenge of the intermittent nature of the renewable energy and the unpredictability of the load …

Optimizing Distributed Generation Parameters Through Economic Feasibility Assessment, Kashem M. Muttaqi, An D. T Le, Jamshid Aghaei, Esmaeil Mahboubi-Moghaddam, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

To meet the fast growth of electricity demand, the traditional network solution tends to expand existing substations, build more new substations, and build transmission lines. Distributed Generation (DG) is posed as an alternative method for the network providers not only to accommodate the load increase and relieve network overload, but also to offer other additional technical and economic benefits. This paper addresses the issue of DG planning and has proposed a technique for optimizing the DG size and location to minimize the overall investment and operational cost of the system. The proposed optimization methodology assesses the compatibility of different generation …

Seismic Rehabilitation Of Reinforced Concrete Beam-Column Joints By Bonding With Concrete Covers And Wrapping With Frp Composites, Muhammad N. S Hadi, Tung M. Tran

Faculty of Engineering and Information Sciences - Papers: Part A

This study evaluates the effectiveness of a new method for seismic strengthening of exterior RC beam-column connections and develops a joint shear strength model for the strengthened connections. Four RC exterior connections without transverse reinforcement at the joints were cast and tested under reverse cyclic loading. The first connection was tested as the control specimen while the three remaining connections were glued with concrete covers around the columns at the joint area to modify them from square to circular sections and then they were wrapped with different ratios of CFRP for strengthening. The joint shear strength model was developed based …

Modelling Long-Term Deformation Of Granular Soils Incorporating The Concept Of Fractional Calculus, Yifei Sun, Yang Xiao, Changjie Zheng, Khairul Fikry Hanif

Faculty of Engineering and Information Sciences - Papers: Part A

Many constitutive models exist to characterise the cyclic behaviour of granular soils but can only simulate deformations for very limited cycles. Fractional derivatives have been regarded as one potential instrument for modelling memory-dependent phenomena. In this paper, the physical connection between the fractional derivative order and the fractal dimension of granular soils is investigated in detail. Then a modified elasto-plastic constitutive model is proposed for evaluating the long-term deformation of granular soils under cyclic loading by incorporating the concept of factional calculus. To describe the flow direction of granular soils under cyclic loading, a cyclic flow potential considering particle breakage …

Phosphorus Recovery From Digested Sludge Centrate Using Seawater-Driven Forward Osmosis, Ashley J. Ansari, Faisal I. Hai, William E. Price, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

In this study, we demonstrate a novel seawater-driven forward osmosis (FO) process to recover calcium phosphate precipitates from digested sludge centrate without any chemical addition and draw solute regeneration. The FO process effectively pre-concentrated phosphate and calcium in the digested sludge centrate. Spontaneous precipitation of calcium phosphate minerals in the digested sludge centrate was achieved by the sustained concentrative action of the FO process and the gradual pH increase due to the diffusion of protons to the draw solution. Pre-concentrating digested sludge centrate by three-fold resulted in a 92% recovery of phosphate via precipitation. The phosphate precipitate only constituted 3% …

Efficient Dynamic Threshold Identity-Based Encryption With Constant-Size Ciphertext, Willy Susilo, Fuchun Guo, Yi Mu

Faculty of Engineering and Information Sciences - Papers: Part A

This paper revisits the notion of dynamic threshold identity-based encryption, due to the recent practical interest. In this notion, an encryptor selects n recipients and a threshold value t for the creation of the ciphertext. The plaintext can only be recovered if at least t receivers cooperate. The key issue in this notion is its dynamicity, where after the users enroll to the system, the sender can dynamically select the set of recipients as well as dynamically set the threshold t upon the creation of the ciphertext. Another essential feature of this notion is the need for a constant-size ciphertext. …

Nursing Staff Work Patterns In A Residential Aged Care Home: A Time-Motion Study, Siyu Qian, Ping Yu, David Hailey

Faculty of Engineering and Information Sciences - Papers: Part A

Objective: Residential aged care services are challenged by an increasing number of residents and a shortage of nursing staff. Developing strategies to overcome this challenge requires an understanding of nursing staff work patterns. The aim of the present study was to investigate the work processes followed by nursing staff and how nursing time is allocated in a residential aged care home.

Methods: An observational time-motion study was conducted at two aged care units for 12 morning shifts. Seven nurses were observed, one per shift.

Results: In all, there were 91 h of observation. The results showed that there was a …

Synthesis Of Sic Whiskers By Vls And Vs Process, Xiang Li, Guangqing Zhang, Ragnar Tronstad, Oleg Ostrovski

Faculty of Engineering and Information Sciences - Papers: Part A

This study investigates the mechanisms of SiC whisker formation in the carbothermal reduction of quartz to SiC in different gas atmospheres. Reduction of quartz by graphite was studied in Ar, H2, and CH4-H2-Ar gas mixture in a laboratory fixed bed reactor. The reduction products were characterised by XRD, SEM and TEM. Whiskers were not formed in the carbothermal reduction of quartz in argon. Two types of SiC whiskers were observed in the carbothermal reduction of quartz in H2 and CH4-H2-Ar gas mixture. In the process of reduction at 1400-1600 °C in H2 and at 1200-1600 °C in CH4-H2-Ar gas mixture, …

Mechanical Properties And Tribological Behavior Of Aluminum Matrix Composites Reinforced With In-Situ Alb2 Particles, Linlin Yuan, Jingtao Han, Jing Liu, Zhengyi Jiang

Faculty of Engineering and Information Sciences - Papers: Part A

Aluminum matrix composites (AMCs) reinforced with in-situ AlB₂ particles have been fabricated using a combination of powder metallurgy, hot rolling and solution treatment. The effects of boron content (7 and 12 wt%), hot rolling and heat treatment parameters on the microstructures and mechanical properties of the composites were investigated by means of scanning electron microscopy (SEM), tensile test and micro-hardness measurements. The friction coefficient, wear behavior and scratch morphology of the AMCs and pure aluminum were also studied using scratch tests. The hardness and wear properties are higher in a case of composites when compared to unreinforced matrix material.

Biodegradation Of Cellulose Triacetate And Polyamide Forward Osmosis Membranes In An Activated Sludge Bioreactor: Observations And Implications, Wenhai Luo, Ming Xie, Faisal I. Hai, William E. Price, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

This study investigated long-term stability of forward osmosis (FO) membranes against biodegradation during prolonged exposure to activated sludge. Results show that cellulose triacetate (CTA) membranes were more resistant against biodegradation than polyamide thin film composite (TFC) ones. Nevertheless, CTA membrane biodegradation was discernible after seven months of exposure to activated sludge as manifested by an increase in the membrane average pore size, water and salt permeability, and membrane structural parameter. Asaresult, of prolonged exposure to activated sludge, the water and reverse salt fluxes of the CTA membrane increased; and concomitantly the rejection of a range of trace organic contaminants decreased …

Coupled Discrete-Continuum Method For Studying Load-Deformation Of A Stone Column Reinforces Rail Track Embankments, Ngoc Trung Ngo, Tran Minh Tung

Faculty of Engineering and Information Sciences - Papers: Part A

Stone columns are being increasingly used as a cost-effective and environmentally friendly method for reinforcing soft soils of rail track embankments. Deformation behavior of stone columns reinforced soft clay has been the subject of an extensive number of experimental and modelling studies during last decades. A continuum-based numerical method provides valuable insights into the settlement, lateral deformation, stress and strain-rate dependent behavior of stone column at macroscopic scale. However, due to the discrete nature of stone columns, which are comprised of granular aggregates, they cannot be properly modelled by the continuum methods. This paper presents a novel coupling model of …

Predicting Dropout In Dietary Weight Loss Trials Using Demographic And Early Weight Change Characteristics: Implications For Trial Design, Marijka Batterham, Linda C. Tapsell, Karen E. Charlton

Faculty of Engineering and Information Sciences - Papers: Part A

Summary Attrition causes analytical and efficacy issues in weight loss trials. Consistent predictors of attrition in weight loss trials have not been identified. Trial design could be improved if factors predicting attrition are accounted for. The aim of this study is to quantify the effect of easily measured pre study and early study variables to determine their relationship with attrition in dietary weight loss trials. Methods Data was pooled from four previous dietary weight loss trials. Mixed effects logistic regression, Receiver Operator Curves and decision trees (classification and regression trees) were used to determine which of the variables (percent weight …

Quadratic Autocatalysis In An Extended Continuous-Flow Stirred Tank Reactor (Ecstr), Mark Nelson, E Balakrishnan

Faculty of Engineering and Information Sciences - Papers: Part A

The continuous-flow stirred tank reactor (CSTR) is a standard tool used to investigate the behaviour of chemical processes subject to nonlinear kinetics. A recently proposed variation of the CSTR is the extended continuous-flow stirred tank reactor (ECSTR). This consists of a standard CSTR attached to an environmental tank reactor with mass transfer occurring between them through a membrane. The attraction of studying a reaction scheme in an ECSTR, rather than a CSTR, is that this offers the possibility of modifying the behaviour with a larger parameter dimension. We investigate how the behaviour of a standard non-linear chemical mechanism, quadratic autocatalysis …

A Schauder Estimate For Stochastic Pdes, Kai Du, Jiakun Liu

Faculty of Engineering and Information Sciences - Papers: Part A

Considering stochastic partial differential equations of parabolic type with random coefficients in vector-valued Hölder spaces, we establish a sharp Schauder theory. The existence and uniqueness of solutions to the Cauchy problem is obtained.

Pricing European Options With Stochastic Volatility Under The Minimal Entropy Martingale Measure, Xin-Jiang He, Song-Ping Zhu

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, a closed-form pricing formula in the form of an infinite series for European call options is derived for the Heston stochastic volatility model under a chosen martingale measure. Given that markets with the stochastic volatility are incomplete, there exists a number of equivalent martingale measures and consequently investors face a problem of making a choice of appropriate measure when they price options. The one we adopt here is the so-called minimal entropy martingale measure shown to be related to the expected utility maximization theory (Frittelli 2000 Math. Finance 10(1), 39-52) and the financial rationality for choosing this …