RMITOpt-SPACE meeting: Dr Elisa Maria Alessi: Passive End-of-Life Solutions for Low Earth Orbits

RMITOpt-SPACE meeting: Dr Elisa Maria Alessi: Passive End-of-Life Solutions  for Low Earth Orbits

Speaker: Dr Elisa Maria Alessi
Istituto di Fisica Applicata “Nello Carrara” (IFAC),
Consiglio Nazionale delle Ricerche (CNR), Italy

Title: Passive End-of-Life Solutions for Low Earth Orbits

Date and time: Monday 9 October 2017, 3:30–4:30pm – note unusual day and time
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract: The growing awareness of the space debris problem has motivated the scientific community to look for effective and feasible active and passive end-of-life disposal solutions for spacecraft orbiting the Earth, in particular the Low Earth Orbit (LEO) region. It is now recognized the idea that the mission design must comprise end-of-life strategies to preserve the space environment and for the sustainability of the whole program. To this end and to make it affordable, it is mandatory to achieve a deep understanding of the dynamics pervading the circumterrestrial space. Starting from an explanatory introduction on the problem and on the worlwide effort, the talk will address the recent advancements obtained in the framework of the ReDSHIFT H2020 project concerning the dynamical mapping of the LEO region, by means of extensive numerical simulations and analytical studies of the resonances due to solar radiation pressure and third-body perturbations. Read more

RMITOpt-SPACE meeting: Dr Pierfrancesco Di Cintio, Chaos, noise, discreteness effects and the continuum limit in N-body systems, revisited

RMITOpt-SPACE meeting: Dr Pierfrancesco Di Cintio, Chaos, noise, discreteness effects and the continuum limit in N-body systems, revisited

Speaker: Dr Pierfrancesco Di Cintio
Institute of Applied Physics of the National Council of Research (IFAC-CNR)
Title: Chaos, noise, discreteness effects and the continuum limit in N-body systems, revisited
Date and time: Monday 2 October 2017, 3:30–4:30pm – note unusual day and time
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract: In this talk I will question the validity of the continuum limit and the use of frozen N-body realizations to obtain qualitative information on particle orbits in large N gravitational system in stellar dynamics. With the aid of detailed numerical simulations with refined symplectic integrators developed in the context of numerical celestial mechanics, I will compare orbits in frozen potentials with orbits in self consistent equilibrium models. In addition, I will show some results that could be relevant for the physics of charged particle beams. Read more

CANCELLED: Reinout Quispel, Geometric numerical integration: how to discretize differential equations while preserving their physical properties

CANCELLED: Reinout Quispel, Geometric numerical integration: how to discretize differential equations while preserving their physical properties

THIS TALK IS CANCELLED

Speaker: Prof. Reinout Quispel
La Trobe University
Title: Geometric numerical integration: how to discretize differential equations while preserving their physical properties
Date and time: Friday 13 October 2017, 3:00–4:00pm
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract:
In this talk we give a survey of geometric numerical integration, i.e. the numerical solution of differential equations while preserving one or more of their physical properties exactly, i.e. up to round-off error. Properties that can be preserved include symplectic structure, energy and other first integrals, phase space volume, symmetries, dissipation, etc.

Bio:

1976
B.Sc. University of Utrecht, The Netherlands.
1979
M.Sc. University of Utrecht.
1979–1983
Research Associate at Leiden University, The Netherlands.
1983
Ph.D, Leiden University. Title of Thesis: “Linear Integral Equations and Soliton Systems”, supervisor: Hans W. Capel.
1983–1985
Postdoctoral Fellow at Twente University, The Netherlands.
1985–1986
Assistant Professor at Department of Mathematics, Utrecht University.
1986–1990
(Senior) Research Fellow at Australian National University.
1990–2003
Lecturer/Senior Lecturer/Reader at La Trobe University, Department of Mathematics.
2000
Reader at University of Cambridge (visiting position at DAMTP from April until July).
2004–present
Professor of Mathematics at La Trobe University.
2008–2012
ARC Australian Professorial Fellowship.
2013
Onsager Professorship and Medal (Norwegian University of Science and Technology, Trondheim).
2014–2016
ARC Distinguished Outstanding Researcher Award.

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Walter Kozlowski, Common fixed points of semigroups of monotone nonexpansive nonlinear mappings in Banach spaces

Walter Kozlowski, Common fixed points of semigroups of monotone nonexpansive nonlinear mappings in Banach spaces

Speaker: Walter Kozlowski
University of New South Wales
Title: Common fixed points of semigroups of monotone nonexpansive nonlinear mappings in Banach spaces
Date and time: Friday 8 September 2017, 3:00–4:00pm
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract:
We consider semigroups of nonlinear mappings acting in Banach spaces equipped with a partial order. We assume that these mappings are monotone and nonexpansive on elements comparable in the order sense. We will discuss existence of common fixed points for such semigroups as well as algorithms for construction of such fixed points. We will also touch upon applications to differential equations and dynamical systems. Read more

IMO2017 session on 4 September

IMO2017 session on 4 September

After the successful meeting on Putnam problems last Monday we are continuing the theme with International Mathematical Olympiad problems.

Topic: International Mathematical Olympiad 2017 (IMO2017) problems
Time and Venue: Monday 4 September 3:30pm, AGR 8.9.66
Description: Download the problems in your favourite language: https://www.imo-official.org/year_info.aspx?year=2017 and try solving them before the meeting. During the meeting we will discuss the solutions.
Coordinator: Ben Haire.

Dr Irene Strodthoff, Bushfires and the community in Chile and Australia

Dear Optimisation Group members,

Please note the following seminar talk given by Dr Irene Strodthoff who is currently visiting Prof. John Handmer at RMIT.

Speaker: Dr Irene Strodthoff
Visiting researcher at the Risk and Community Safety research program, School of Science, RMIT University & Academia Nacional de Estudios Politicos y Estrategicos (ANEPE), Chile
Time and venue: Friday 1 September, 2-4pm, Board Room 325, La Trobe City Campus, 215 Franklin St, opposite Victoria Market.
Title: Bushfires and the community in Chile and Australia: How cultural and governmental contexts have an impact on preparedness and response

For the information on this and other seminars of the Institute of Latin American Studies (ILAS) of La Trobe University, Download flyer.

CIAO Seminar: Jeffrey Christiansen, Decomposition and duality for Stochastic Integer Programs

CIAO Seminar: Jeffrey Christiansen, Decomposition and duality for Stochastic Integer Programs

Speaker: Mr Jeffrey Christiansen
RMIT University

Time and Location: Thursday, August 31 at 11:30 AM–12:30 PM, T121, T Building, Mt Helen Campus

Title: Decomposition and duality for Stochastic Integer Programs

Abstract: Stochastic Integer Programming is a powerful modelling tool for representing decision problems which incorporate elements of uncertainty. As compared to ordinary Integer Programs their scenario-based structure readily lends itself to decomposition and parallel computation techniques. Read more

Musa Mammadov: Mathematical modelling and controlling the dynamics of infectious diseases

Musa Mammadov: Mathematical modelling and controlling the dynamics of infectious diseases

Speaker: Dr Musa Mammadov
Faculty of Science and Technology, Federation University Australia

Title: Mathematical modelling and controlling the dynamics of infectious diseases

Date and time: Friday 25 August 2017, 3:00–4:00pm
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract: Mathematical modeling has played an important role in predicting, assessing and controlling potential outbreaks. In this talk, we will briefly discuss the main approaches used for the modeling of infectious diseases with the major focus on dynamical systems. Read more

Prof. Hong-Kun Xu: Proximal Methods for Convex and Nonconvex Optimization

Prof. Hong-Kun Xu: Proximal Methods for Convex and Nonconvex Optimization

Dear Optimisation group members,

You are cordially invited to attend a talk by Prof. Hong-Kun Xu at RMIT next Monday 14 August at 3:30pm. Please note the unusual time. This is the same talk that was cancelled last Monday.

Speaker: Prof. Hong-Kun Xu
Hangzhou Dianzi University

Title: Proximal Methods for Convex and Nonconvex Optimization

Date and time: Monday 14 August 2017, 3:30–4:30pm – Note unusual day and time
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus

Abstract: The proximal operators are introduced by Moreau (1962) to generalize projections in Hilbert spaces.
They were recently found quite powerful in solving optimization problems which arise from image recovery/reconstruction, signal processing, machine learning, and compressed sensing. A common feature is that the objective function can be written as the sum of two (or more) convex (or even nonconvex) functions, one of which plays the role of regularization. Read more

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