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Full-Text Articles in Science and Technology Studies

Compressive Behaviour Of Partially Frp Confined Concrete: Experimental Observations And Assessment Of The Stress-Strain Models, Weiqiang Wang, M Neaz Sheikh, Ali Qasim Al-Baali, Muhammad N. S Hadi Jan 2018

Compressive Behaviour Of Partially Frp Confined Concrete: Experimental Observations And Assessment Of The Stress-Strain Models, Weiqiang Wang, M Neaz Sheikh, Ali Qasim Al-Baali, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

This study provides new insight on the compressive behaviour of partially fibre reinforced polymer (FRP) confined concrete with either strain-hardening or strain-softening responses. Fully FRP confined concrete, partially FRP confined concrete with different strip gaps, and unconfined concrete were tested under axial compression. Four types of axial load-axial deformation behaviours were observed for specimens with different strip gaps. Even though a high volumetric ratio of FRP was applied, the confinement effectiveness was negligible when the strip gap exceeded the diameter of the specimens. Moreover, the axial stress-axial strain behaviours of wrapped and non-wrapped concrete were observed to be different, and …


Investigation Of Track Structure And Condensed History Physics Models For Applications In Radiation Dosimetry On A Micro And Nano Scale In Geant4, Peter Lazarakis, Sebastien Incerti, Vladimir N. Ivanchenko, Ioanna Kyriakou, Dimitris Emfietzoglou, Stephanie Corde, Anatoly B. Rosenfeld, Michael L. F Lerch, Moeava Tehei, Susanna Guatelli Jan 2018

Investigation Of Track Structure And Condensed History Physics Models For Applications In Radiation Dosimetry On A Micro And Nano Scale In Geant4, Peter Lazarakis, Sebastien Incerti, Vladimir N. Ivanchenko, Ioanna Kyriakou, Dimitris Emfietzoglou, Stephanie Corde, Anatoly B. Rosenfeld, Michael L. F Lerch, Moeava Tehei, Susanna Guatelli

Faculty of Engineering and Information Sciences - Papers: Part B

Monte Carlo methods apply various physical models, either condensed history (CH) or track structure (TS), to simulate the passage of radiation through matter. Both CH and TS models continue to be applied to radiation dosimetry investigations on a micro and nano scale. However, as there has been no systematic comparison of the use of these models for such applications there can be no quantification of the uncertainty that is being introduced by the choice of physics model. A comparison of CH and TS models available in Geant4, along with a quantification of the differences in calculated quantities on a micro …


A Problem Of Play For Democratic Education? Abstraction, Realism, And Exploration In Learning Games. A Response To "The Challenges Of Gaming For Democratic Education: The Case Of Icivics", Benjamin Devane Dec 2017

A Problem Of Play For Democratic Education? Abstraction, Realism, And Exploration In Learning Games. A Response To "The Challenges Of Gaming For Democratic Education: The Case Of Icivics", Benjamin Devane

Democracy and Education

In this review article, I argue that games are complementary, not self-supporting, learning tools for democratic education because they can: (a) offer simplified, but often not simple, outlines (later called “models”) of complex social systems that generate further inquiry; (b) provide practice spaces for exploring systems that do not have the often serious consequences of taking direct and immediate social, civic, and legal action; and (c) use rules to allow players to explore this aforementioned outline or model by making decisions and seeing an outcome. To make these arguments, I perform a close reading of three examples of participatory …


Threat Models For Analyzing Plausible Deniability Of Deniable File Systems, Michal Kedziora, Yang-Wai Chow, Willy Susilo Jan 2017

Threat Models For Analyzing Plausible Deniability Of Deniable File Systems, Michal Kedziora, Yang-Wai Chow, Willy Susilo

Faculty of Engineering and Information Sciences - Papers: Part B

Plausible deniability is a property of Deniable File System (DFS), which are encrypted using a Plausibly Deniable Encryption (PDE) scheme, where one cannot prove the existence of a hidden file system within it. This paper investigates widely used security models that are commonly employed for analyzing DFSs. We contend that these models are no longer adequate considering the changing technological landscape that now encompass platforms like mobile and cloud computing as a part of everyday life. This necessitates a shift in digital forensic analysis paradigms, as new forensic models are required to detect and analyze DFSs. As such, it is …


Using Contrastive Divergence To Seed Monte Carlo Mle For Exponential-Family Random Graph Models, Pavel N. Krivitsky Jan 2017

Using Contrastive Divergence To Seed Monte Carlo Mle For Exponential-Family Random Graph Models, Pavel N. Krivitsky

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential-family models for dependent data have applications in a wide variety of areas, but the dependence often results in an intractable likelihood, requiring either analytic approximation or MCMC-based techniques to fit, the latter requiring an initial parameter configuration to seed their simulations. A poor initial configuration can lead to slow convergence or outright failure. The approximate techniques that could be used to find them tend not to be as general as the simulation-based and require implementation separate from that of the MLE-finding algorithm. Contrastive divergence is a more recent simulation-based approximation technique that uses a series of abridged MCMC runs …


Sharing Social Network Data: Differentially Private Estimation Of Exponential Family Random-Graph Models, Vishesh Karwa, Pavel N. Krivitsky, Aleksandra B. Slavkovic Jan 2017

Sharing Social Network Data: Differentially Private Estimation Of Exponential Family Random-Graph Models, Vishesh Karwa, Pavel N. Krivitsky, Aleksandra B. Slavkovic

Faculty of Engineering and Information Sciences - Papers: Part A

Motivated by a real life problem of sharing social network data that contain sensitive personal information, we propose a novel approach to release and analyse synthetic graphs to protect privacy of individual relationships captured by the social network while maintaining the validity of statistical results. A case-study using a version of the Enron e-mail corpus data set demonstrates the application and usefulness of the proposed techniques in solving the challenging problem of maintaining privacy and supporting open access to network data to ensure reproducibility of existing studies and discovering new scientific insights that can be obtained by analysing such data. …


Linear Regression Models For Prediction Of Annual Heating And Cooling Demand In Representative Australian Residential Dwellings, Navid Aghdaei, Georgios Kokogiannakis, Daniel J. Daly, Timothy J. Mccarthy Jan 2017

Linear Regression Models For Prediction Of Annual Heating And Cooling Demand In Representative Australian Residential Dwellings, Navid Aghdaei, Georgios Kokogiannakis, Daniel J. Daly, Timothy J. Mccarthy

Faculty of Engineering and Information Sciences - Papers: Part B

This paper presents the development methodology of linear regression models that were developed for the prediction of annual thermal loads in representative residential buildings across three major climates in New South Wales, Australia, and the assessment of the impact of building envelope upgrades. A differential sensitivity analysis was undertaken for sixteen building envelope parameters, with six parameters being identified as significant. These six parameters were then explored using EnergyPlus simulation, and a number of linear regression models developed from the simulation outputs. Random values for design parameters were generated, and the results of EnergyPlus simulations using these parameters were used …


A Comparison Study For Supervised Machine Learning Models In Cancer Classification, Huaming Chen, Hong Zhao, Lei Wang, Jiangning Song, Jun Shen Jan 2017

A Comparison Study For Supervised Machine Learning Models In Cancer Classification, Huaming Chen, Hong Zhao, Lei Wang, Jiangning Song, Jun Shen

Faculty of Engineering and Information Sciences - Papers: Part B

No abstract provided.


Optimizing Wearable Assistive Devices With Neuromuscular Models And Optimal Control, Manish Sreenivasa, Matthew Millard, Paul Manns, Katja Mombaur Jan 2017

Optimizing Wearable Assistive Devices With Neuromuscular Models And Optimal Control, Manish Sreenivasa, Matthew Millard, Paul Manns, Katja Mombaur

Faculty of Engineering and Information Sciences - Papers: Part B

The coupling of human movement dynamics with the function and design of wearable assistive devices is vital to better understand the interaction between the two. Advanced neuromuscular models and optimal control formulations provide the possibility to study and improve this interaction. In addition, optimal control can also be used to generate predictive simulations that generate novel movements for the human model under varying optimization criterion.


Joint Pet-Mr Respiratory Motion Models For Clinical Pet Motion Correction, Richard Manber, Kris Thielemans, Brian F. Hutton, Simon Wan, Jamie Mcclelland, Anna Barnes, Simon R. Arridge, Sebastien Ourselin, David Atkinson Jan 2016

Joint Pet-Mr Respiratory Motion Models For Clinical Pet Motion Correction, Richard Manber, Kris Thielemans, Brian F. Hutton, Simon Wan, Jamie Mcclelland, Anna Barnes, Simon R. Arridge, Sebastien Ourselin, David Atkinson

Faculty of Engineering and Information Sciences - Papers: Part A

Patient motion due to respiration can lead to artefacts and blurring in positron emission tomography (PET) images, in addition to quantification errors. The integration of PET with magnetic resonance (MR) imaging in PET-MR scanners provides complementary clinical information, and allows the use of high spatial resolution and high contrast MR images to monitor and correct motion-corrupted PET data. In this paper we build on previous work to form a methodology for respiratory motion correction of PET data, and show it can improve PET image quality whilst having minimal impact on clinical PET-MR protocols. We introduce a joint PET-MR motion model, …


Flexible Analysis Of Digital Pcr Experiments Using Generalized Linear Mixed Models, Matthijs Vynck, J Vandesompele, Nele Nijs, Björn Menten, Ariane De Ganck, Olivier Thas Jan 2016

Flexible Analysis Of Digital Pcr Experiments Using Generalized Linear Mixed Models, Matthijs Vynck, J Vandesompele, Nele Nijs, Björn Menten, Ariane De Ganck, Olivier Thas

Faculty of Engineering and Information Sciences - Papers: Part A

The use of digital PCR for quantification of nucleic acids is rapidly growing. A major drawback remains the lack of flexible data analysis tools. Published analysis approaches are either tailored to specific problem settings or fail to take into account sources of variability. We propose the generalized linear mixed models framework as a flexible tool for analyzing a wide range of experiments. We also introduce a method for estimating reference gene stability to improve accuracy and precision of copy number and relative expression estimates. We demonstrate the usefulness of the methodology on a complex experimental setup.


Interaction Prediction Between Groundwater And Quarry Extension Using Discrete Choice Models And Artificial Neural Networks, Johan Barthelemy, Timoteo Carletti, Louise Collier, Vincent Hallet, Marie Moriame, Annick Sartenear Jan 2016

Interaction Prediction Between Groundwater And Quarry Extension Using Discrete Choice Models And Artificial Neural Networks, Johan Barthelemy, Timoteo Carletti, Louise Collier, Vincent Hallet, Marie Moriame, Annick Sartenear

Faculty of Engineering and Information Sciences - Papers: Part A

Groundwater and rock are intensively exploited in the world. When a quarry is deepened the water table of the exploited geological formation might be reached. A dewatering system is therefore installed so that the quarry activities can continue, possibly impacting the nearby water catchments. In order to recommend an adequate feasibility study before deepening a quarry, we propose two interaction indices between extractive activity and groundwater resources based on hazard and vulnerability parameters used in the assessment of natural hazards. The levels of each index (low, medium, high, very high) correspond to the potential impact of the quarry on the …


An Implementation Of Discrete Electron Transport Models For Gold In The Geant4 Simulation Toolkit, D Sakata, Sebastien Incerti, M Bordage, N Lampe, Susumu Okada, Dimitris Emfietzoglou, Ioanna Kyriakou, K Murakami, Takashi Sasaki, H Tran, Susanna Guatelli, V Ivantchenko Jan 2016

An Implementation Of Discrete Electron Transport Models For Gold In The Geant4 Simulation Toolkit, D Sakata, Sebastien Incerti, M Bordage, N Lampe, Susumu Okada, Dimitris Emfietzoglou, Ioanna Kyriakou, K Murakami, Takashi Sasaki, H Tran, Susanna Guatelli, V Ivantchenko

Faculty of Engineering and Information Sciences - Papers: Part A

Gold nanoparticle (GNP) boosted radiation therapy can enhance the biological effectiveness of radiation treatments by increasing the quantity of direct and indirect radiation-induced cellular damage. As the physical effects of GNP boosted radiotherapy occur across energy scales that descend down to 10 eV, Monte Carlo simulations require discrete physics models down to these very low energies in order to avoid underestimating the absorbed dose and secondary particle generation. Discrete physics models for electron transportation down to 10 eV have been implemented within the Geant4-DNA low energy extension of Geant4. Such models allow the investigation of GNP effects at the nanoscale. …


Factor Analytic Mixed Models For The Provision Of Grower Information From National Crop Variety Testing Programs, Alison B. Smith, Aanandini Ganesalingam, Haydn Kuchel, Brian R. Cullis Jan 2015

Factor Analytic Mixed Models For The Provision Of Grower Information From National Crop Variety Testing Programs, Alison B. Smith, Aanandini Ganesalingam, Haydn Kuchel, Brian R. Cullis

Faculty of Engineering and Information Sciences - Papers: Part A

Crop variety testing programs are conducted in many countries world-wide. Within each program, data are combined across locations and seasons, and analysed in order to provide information to assist growers in choosing the best varieties for their conditions. Despite major advances in the statistical analysis of multi-environment trial data, such methodology has not been adopted within national variety testing programs. The most commonly used approach involves a variance component model that includes variety and environment main effects, and variety by environment ( VxE ) interaction effects. The variety predictions obtained from such an analysis, and subsequently reported to growers, are …


Calibrating Markov Chain-Based Deterioration Models For Predicting Future Conditions Of Railway Bridge Elements, Niroshan Walgama Wellalage, Tieling Zhang, Richard Dwight Jan 2015

Calibrating Markov Chain-Based Deterioration Models For Predicting Future Conditions Of Railway Bridge Elements, Niroshan Walgama Wellalage, Tieling Zhang, Richard Dwight

Faculty of Engineering and Information Sciences - Papers: Part A

Existing nonlinear optimization-based algorithms for estimating Markov transition probability matrix (TPM) in bridge deterioration modeling sometimes fail to find optimum TPM values, and hence lead to invalid future condition prediction. In this study, a Metropolis-Hasting algorithm (MHA)-based Markov chain Monte Carlo (MCMC) simulation technique is proposed to overcome this limitation and calibrate the state-based Markov deterioration models (SBMDM) of railway bridge components. Factors contributing to rail bridge deterioration were identified; inspection data for 1,000 Australian railway bridges over 15 years were reviewed and filtered. The TPMs corresponding to a typical bridge element were estimated using the proposed MCMC simulation method …


Interpreting, Stephanie Jo Kent Aug 2014

Interpreting, Stephanie Jo Kent

Doctoral Dissertations

What do community interpreting for the Deaf in western societies, conference interpreting for the European Parliament, and language brokering in international management have in common? Academic research and professional training have historically emphasized the linguistic and cognitive challenges of interpreting, neglecting or ignoring the social aspects that structure communication. All forms of interpreting are inherently social; they involve relationships among at least three people and two languages. The contexts explored here, American Sign Language/English interpreting and spoken language interpreting within the European Parliament, show that simultaneous interpreting involves attitudes, norms and values about intercultural communication that overemphasize information and discount …


Elastic Models For Nonlinear Response Of Rigid Passive Piles, Wei Dong Guo Jan 2014

Elastic Models For Nonlinear Response Of Rigid Passive Piles, Wei Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

Recent study indicates that the response of rigid passive piles is dominated by elastic pile–soil interaction and may be estimated using theory for lateral piles. The difference lies in that passive piles normally are associated with a large scatter of the ratio of maximum bending moment over maximum shear force and induce a limiting pressure that is ~1/3 that on laterally loaded piles. This disparity prompts this study.

This paper proposes pressure-based pile–soil models and develops their associated solutions to capture response of rigid piles subjected to soil movement. The impact of soil movement was encapsulated into a power-law distributed …


Inconsistency Resolution In Merging Versions Of Architectural Models, Hoa Dam, Alexander Reder, Alexander Egyed Jan 2014

Inconsistency Resolution In Merging Versions Of Architectural Models, Hoa Dam, Alexander Reder, Alexander Egyed

Faculty of Engineering and Information Sciences - Papers: Part A

State-of-the-art optimistic model versioning systems, which are critical to enable efficient team-based development of architectural models, are able to detect and help resolve basic conflicts arising during the merging of model versions. However, it is often overlooked that model merging may also cause severe syntactical and semantic inconsistencies. In this paper, we propose an approach to guide the resolution of inconsistencies detected in a merged architectural model. Our approach automatically finds and presents to the software architects all solutions for resolving all inconsistencies arisen during the merging of model versions. For inconsistencies that preexist in the model, our approach is …


Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola Dec 2013

Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola

Dr Lasantha G Meegahapola

Wind power generation has indicated an exponential increase during last two decades and existing transmission network infrastructure is increasingly becoming inadequate to transmit remotely generated wind power to load centres in the network. The dynamic line rating (DLR) is one of the viable solutions to improve the transmission line ampacity during high wind penetration without investing on an additional transmission network. The main objective of this study is to identify the basic differences between two main line rating standards, since transmission network service providers (TNSPs) heavily depend on these two standards when developing their line rating models. Therefore, a parameter …


Compare Pilot-Scale And Industry-Scale Models Of Pulverized Coal Combustion In An Ironmaking Blast Furnace, Yansong Shen, Aibing Yu, Paul Zulli Jan 2013

Compare Pilot-Scale And Industry-Scale Models Of Pulverized Coal Combustion In An Ironmaking Blast Furnace, Yansong Shen, Aibing Yu, Paul Zulli

Faculty of Engineering and Information Sciences - Papers: Part A

In order to understand the complex phenomena of pulverized coal injection (PCI) process in blast furnace (BF), mathematical models have been developed at different scales: pilot-scale model of coal combustion and industry-scale model (in-furnace model) of coal/coke combustion in a real BF respectively. This paper compares these PCI models in aspects of model developments and model capability. The model development is discussed in terms of model formulation, their new features and geometry/regions considered. The model capability is then discussed in terms of main findings followed by the model evaluation on their advantages and limitations. It is indicated that these PCI …


A Study On The Suitability Of Cable Models To Simulate Switching Transients In A 132 Kv Underground Cable, Muhamad Zalani Daud, P Ciufo, S Perera Jan 2013

A Study On The Suitability Of Cable Models To Simulate Switching Transients In A 132 Kv Underground Cable, Muhamad Zalani Daud, P Ciufo, S Perera

Faculty of Engineering and Information Sciences - Papers: Part A

Switching transients resulting from the energisation of high voltage cable systems may have a significant effect on both the cables being switched as well as the power system components in the vicinity. The impacts of these transients on such cables are measured based on the stress arising as a result of the voltage and current peaks and the frequency of oscillatory transients. These quantities are typically obtained from a simulation by using a suitable cable model, normally with the capability to predict the transient behaviour in the range up to several 10 kHz. To obtain a cable model that enables …


Exact Travelling Wave Solutions For Some Important Nonlinear Physical Models, Jonu Lee, Rathinasamy Sakthivel Jan 2013

Exact Travelling Wave Solutions For Some Important Nonlinear Physical Models, Jonu Lee, Rathinasamy Sakthivel

Faculty of Engineering and Information Sciences - Papers: Part A

The two-dimensional nonlinear physical models and coupled nonlinear systems such as Maccari equations, Higgs equations and Schrodinger-KdV equations have been widely applied in many branches of physics. So, finding exact travelling wave solutions of such equations are very helpful in the theories and numerical studies. In this paper, the Kudryashov method is used to seek exact travelling wave solutions of such physical models. Further, three-dimensional plots of some of the solutions are also given to visualize the dynamics of the equations. The results reveal that the method is a very effective and powerful tool for solving nonlinear partial differential equations …


Essential Elements In Tactical Planning Models For Container Liner Shipping, Shuaian Wang Jan 2013

Essential Elements In Tactical Planning Models For Container Liner Shipping, Shuaian Wang

Faculty of Engineering and Information Sciences - Papers: Part A

Tactical planning models for liner shipping problems such as network design and fleet deployment usually minimize the total cost or maximize the total profit subject to constraints including ship availability, service frequency, ship capacity, and transshipment. Most models in the literature do not consider slot-purchasing, multi-type containers, empty container repositioning, or ship repositioning, and they formulate the numbers of containers to transport as continuous variables. This paper develops a mixed-integer linear programming model that captures all these elements. It further examines from the theoretical point of view the additional computational burden introduced by incorporating these elements in the planning model. …


Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola Jan 2013

Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola

Faculty of Engineering and Information Sciences - Papers: Part A

Wind power generation has indicated an exponential increase during last two decades and existing transmission network infrastructure is increasingly becoming inadequate to transmit remotely generated wind power to load centres in the network. The dynamic line rating (DLR) is one of the viable solutions to improve the transmission line ampacity during high wind penetration without investing on an additional transmission network. The main objective of this study is to identify the basic differences between two main line rating standards, since transmission network service providers (TNSPs) heavily depend on these two standards when developing their line rating models. Therefore, a parameter …


Stochastic Volatility Models And The Pricing Of Vix Options, Joanna Goard, Mathew Mazur Jan 2013

Stochastic Volatility Models And The Pricing Of Vix Options, Joanna Goard, Mathew Mazur

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper we examine and compare the performance of a variety of continuous- time volatility models in their ability to capture the behaviour of the VIX. The `3/2- model' with a di®usion structure which allows the volatility of volatility changes to be highly sensitive to the actual level of volatility is found to outperform all other popular models tested. Analytic solutions for option prices on the VIX under the 3/2- model are developed and then used to calibrate at-the-money market option prices.


The Critical Role Of Mechanism-Based Models For Understanding And Predicting Liposomal Drug Loading, Binding And Release Kinetics, Sweta Modi Jan 2013

The Critical Role Of Mechanism-Based Models For Understanding And Predicting Liposomal Drug Loading, Binding And Release Kinetics, Sweta Modi

Theses and Dissertations--Pharmacy

Liposomal delivery systems hold considerable promise for improvement of cancer therapy provided that critical formulation design criteria can be met. The main objective of the current project was to enable quality by design in the formulation of liposomal delivery systems by developing comprehensive, mechanism-based mathematical models of drug loading, binding and release kinetics that take into account not only the therapeutic requirement but the physicochemical properties of the drug, the bilayer membrane, and the intraliposomal microenvironment.

Membrane binding of the drug affects both drug loading and release from liposomes. The influence of bilayer composition and phase structure on the partitioning …


A Study On The Suitability Of Cable Models To Simulate Switching Transients In A 132 Kv Underground Cable, Muhamad Zalani Daud, P Ciufo, S Perera Dec 2012

A Study On The Suitability Of Cable Models To Simulate Switching Transients In A 132 Kv Underground Cable, Muhamad Zalani Daud, P Ciufo, S Perera

Dr Philip Ciufo

Switching transients resulting from the energisation of high voltage cable systems may have a significant effect on both the cables being switched as well as the power system components in the vicinity. The impacts of these transients on such cables are measured based on the stress arising as a result of the voltage and current peaks and the frequency of oscillatory transients. These quantities are typically obtained from a simulation by using a suitable cable model, normally with the capability to predict the transient behaviour in the range up to several 10 kHz. To obtain a cable model that enables …


Exponential-Family Random Graph Models For Valued Networks, Pavel N. Krivitsky Jan 2012

Exponential-Family Random Graph Models For Valued Networks, Pavel N. Krivitsky

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential-family random graph models (ERGMs) provide a principled and flexible way to model and simulate features common in social networks, such as propensities for homophily, mutuality, and friend-of-a- friend triad closure, through choice of model terms (sufficient statistics). However, those ERGMs modeling the more complex features have, to date, been limited to binary data: presence or absence of ties. Thus, analysis of valued networks, such as those where counts, measurements, or ranks are observed, has necessitated dichotomizing them, losing information and introducing biases. In this work, we generalize ERGMs to valued networks. Focusing on modeling counts, we formulate an ERGM …


Marginalized Exponential Random Graph Models, Thomas F. Suesse Jan 2012

Marginalized Exponential Random Graph Models, Thomas F. Suesse

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential random graph models (ERGMs) are a popular tool for modeling social networks representing relational data, such as working relationships or friendships. Data on exogenous variables relating to participants in the network, such as gender or age, are also often collected. ERGMs allow modeling of the effects of such exogenous variables on the joint distribution, specified by the ERGM, but not on the marginal probabilities of observing a relationship. In this article, we consider an approach to modeling a network that uses an ERGM for the joint distribution of the network, but then marginally constrains the fit to agree with …


Estimation In Autoregressive Population Models, Thomas Suesse Jan 2012

Estimation In Autoregressive Population Models, Thomas Suesse

Faculty of Engineering and Information Sciences - Papers: Part A

Autoregressive (AR) models for spatial and social interaction have been proposed by many authors. A sample of units is obtained and the model is applied to this sample. Estimation methods such as the maximum likelihood method (ML) have been employed and investigated in the literature. The main assumption is that a response depends on other responses, when these units interact. Some of those units will be in the sample and some in the non-sample. Therefore the model should apply to the whole population rather to the sample only. Under such a population model, the marginal model for the responses of …