Events
Schedule
Abstracts
Visitors in
Residence
PI/PC List
Institute for Mathematics and its
Applications
University of Minnesota
114 Lind Hall
207 Church Street SE
Minneapolis, MN 55455
Web: http://www.ima.umn.edu | Email: ima-staff@ima.umn.edu | Telephone: (612) 624-6066 | Fax: (612)
626-7370
Additional newsletters available at http://www.ima.umn.edu/newsletters
IMA Newsletter #370
August 2007
News and Notes
The University of Tennessee joins the IMA
The University of Tennessee has joined the IMA as a Participating Institution. The
University of Tennessee's representative on the Participating Institutions Council is
Michael Frazier, the head of the Department of Mathematics.
IMA Events
PI Summer Graduate Program
Applicable Algebraic Geometry
July 23 - August 10, 2007
Organizers: Laura Felicia Matusevich (Texas A & M University), Frank
Sottile (Texas A & M University), Thorsten Theobald (Johann Wolfgang
Goethe-Universität Frankfurt)
Classical and Quantum Approaches in
Molecular Modeling
July 23 - August 3, 2007
Organizers: Eric Cances (CERMICS), Giovanni Ciccotti (Università di Roma
"La Sapienza"), Benedict Leimkuhler (University of Edinburgh), Nicola
Marzari (Massachusetts Institute of Technology), Yousef Saad (University of
Minnesota Twin Cities), Gustavo E. Scuseria (Rice University), Robert D.
Skeel (Purdue University), Mark E. Tuckerman (New York University)
Mathematical Modeling in Industry XI A Workshop for Graduate Students
August 8-17, 2007
Organizers: Richard J. Braun (University of Delaware), Fernando Reitich
(University of Minnesota Twin Cities), Arnd Scheel (University of Minnesota
Twin Cities)
Schedule
Wednesday, August 1
8:30a9:00a
Coffee
EE/CS 3176
9:00a10:00a
Real space pseudopotentials
applied to nanoscale systems
10:00a10:15a
Coffee
10:15a11:15a
Density-functional theory and its
generalizations: legendre
transform, constrained search,
open problems
11:15a11:30a
Coffee
11:30a12:00p
TBA
Matt Challacombe (Los
Alamos National
Laboratory)
EE/CS 3180
12:00p12:30p
Novel materials for quantum
computing
Nicholas M. Harrison
(Imperial College London)
EE/CS 3180
12:30p2:30a
Lunch
2:30p3:00p
Theoretical description of electrons
in single molecule magnets
Ernest R. Davidson
(University of Washington)
EE/CS 3180
3:00p4:00p
A consistent, linear-response
approach to LDA+U
Matteo Cococcioni
(University of Minnesota
Twin Cities)
EE/CS 3180
4:00p4:30p
Real-space finite difference
method for O(N) first-principles
molecular dynamics with plane
waves accuracy
Jean-Luc Fattebert
(Lawrence Livermore
National Laboratory)
EE/CS 3180
4:30p4:45p
Group Photo
4:45p6:15p
Poster Session
James R. Chelikowsky
(University of Texas)
EE/CS 3180
EE/CS 3176
Paul W. Ayers (McMaster
University)
EE/CS 3180
EE/CS 3176
Lind Hall
400
Molecular modelling the structure
and dynamics of alginate
oligosaccharides
Hoda Abdel-Aal Bettley
(University of Manchester)
Method for determination of
Hubbard model phase diagram
from optical lattice experiments by
two parameter scaling
Vivaldo L. Campo
(University of Minnesota
Twin Cities)
Real-space corrections for
electrostatic interactions in
periodic boundary conditions
Ismaila Dabo
(Massachusetts Institute of
Technology)
Objective structures and their
applications
Kaushik Dayal (University
of Minnesota Twin Cities)
Modelling of local defects in
crystals
Amélie Deleurence
(École Nationale des
Ponts-et-Chaussées
(ENPC))
A systematic method to explore
possible silicon tip structures used
in AFM
Seyed-Alireza Ghasemi
(Universität Basel)
Conformational reinvestigation of
two cyclic pentapeptides: to a
generic approach in drug
development
Pieter Hendrickx
(University of Ghent (UG))
An ab initio molecular dynamics
simulation of solid CL-20:
mechanism and kinetics of thermal
decomposition
Olexandr Isayev (Jackson
State University)
Numerical method for solving
stochastic differential equations
with non-Gaussian noise
Changho Kim (Korea
Advanced Institute of
Science and Technology
(KAIST))
Particle-Scaling function (P3S)
algorithm for electrostatic
problems in free boundary
conditions
Alexey Neelov
(Universität Basel)
A Bell-Evans-Polanyi principle for
molecular dynamics trajectories
and its implications for global
optimization
Shantanu Roy
(Universität Basel)
Uniqueness of the density-topotential mapping in excited-state
density-functional theory
Prasanjit Samal
(University of Minnesota
Twin Cities)
Local exchange potentials: A
mathematical viewpoint
Gabriel Stoltz (École
Nationale des Ponts-etChaussées (ENPC))
Precision problems in density
functional development for better
molecular modeling
Michael Teter (Cornell
University)
Mesoscopic model for the
fluctuating hydrodynamics of
binary and ternary mixtures
Erkan Tüzel (North
Dakota State University)
New numerical algorithms and
software for minimizing
biomolecular potential energy
functions
Dexuan Xie (University of
Wisconsin)
Thursday, August 2
8:30a9:00a
Coffee
9:00a10:00a
Wavelets for electronic structure
calculations and electrostatic
problems
10:00a10:15a
Coffee
10:15a11:15a
Exchange and correlation in
electronic systems: the hole story
11:15a11:30a
Coffee
11:30a12:00p
Efficient Kohn-Sham density
functional calculations using the
Gaussian and plane waves
approach
Jürg Hutter
(Universität Zürich)
EE/CS 3180
12:00p12:30p
Van der Waals interactions in
density functional theory
David Langreth (Rutgers
University)
EE/CS 3180
12:30p2:30p
Lunch
2:30p3:00p
Linear-scaling density-functional
calculations with plane-waves
Arash A. Mostofi
(University of Cambridge)
EE/CS 3180
3:00p3:30p
A Linear-scaling AO-based MP2
method for large molecules by
rigorous integral estimates
Christian Ochsenfeld
(Eberhard-KarlsUniversität Tübingen)
EE/CS 3180
3:30p4:00p
Coffee
EE/CS 3-176
4:00p5:30p
Second Chances session on fast
algorithms
EE/CS 3180
6:30p8:30p
Group dinner at Caspian Bistro
Caspian
Bistro 2418
University
Ave SE
Minneapolis,
MN 55414
(612) 6231113
Friday, August 3
8:30a9:00a
Coffee
9:00a-
Dealing with spatial regions
EE/CS 3-176
Stefan Goedecker
(Universität Basel)
EE/CS 3180
EE/CS 3-176
Axel D. Becke (Dalhousie
University)
EE/CS 3180
EE/CS 3-176
EE/CS 3176
Andreas Savin
EE/CS 3-
9:30a
(Université de Paris VI
(Pierre et Marie Curie))
180
9:30a10:00a
Kohn-Sham methods for implicit
density functionals
Viktor N. Staroverov
(University of Western
Ontario)
EE/CS 3180
10:00a10:30a
QM/MM studies on enzymes
Walter Thiel ( MaxPlanck-Institut für
Kohlenforschung)
EE/CS 3180
10:30a11:00a
Coffee
11:00a11:30a
New density functionals: a meta
GGA and three hybrid meta GGAs
with good performance for
thermochemistry, thermochemical
kinetics, noncovalent interactions,
and spectroscopy
Donald G. Truhlar
(University of Minnesota
Twin Cities)
EE/CS 3180
11:30a12:00p
Orbital-Corrected Orbital-Free
density functional theory
Yan Alexander Wang
(University of British
Columbia)
EE/CS 3180
12:00p12:30p
Materials at ultra-high PTs: the
coming of age of planetary
materials theory
Renata Wentzcovitch
(University of Minnesota
Twin Cities)
EE/CS 3180
12:30p2:30a
Lunch
2:30p3:00p
Orbital-free embedding potential:
properties, approximations, and
the use in computer simulations to
couple quantum chemical and
classical levels of description
Tomasz A. Wesolowski
(Université de Genève)
EE/CS 3176
3:00p4:30p
Second Chances session on DFT
EE/CS 3176
EE/CS 3180
Wednesday, August 8
All Day
Workshop Outline: Posing of
problems by the 6 industry
mentors. Half-hour introductory
talks in the morning followed by a
welcoming lunch. In the afternoon,
the teams work with the mentors.
The goal at the end of the day is to
get the students to start working
on the projects.
EE/CS 3180
9:00a9:30a
Coffee and Registration
EE/CS 3176
9:30a9:40a
Welcome and Introduction
Douglas N. Arnold
(University of Minnesota
Twin Cities)
Richard J. Braun
(University of Delaware)
Fernando Reitich
(University of Minnesota
Twin Cities)
Arnd Scheel (University of
Minnesota Twin Cities)
EE/CS 3180
9:40a10:00a
Team 1: Supersonic design
Natalia Alexandrov
(NASA Langley Research
Center)
EE/CS 3180
10:00a10:20a
Team 2: 802.11 WLAN MAC layer
modeling
Radu V. Balan (Siemens
Corporate Research, Inc.)
EE/CS 3180
10:20a10:40a
Team 3: Associating earth-orbiting
objects detected by astronomical
telescopes
Gary B. Green (The
Aerospace Corporation)
EE/CS 3180
10:40a11:00a
Break
11:00a11:20a
Team 4: High dimensional,
nonlinear, non-convex
optimization problems in the area
of aircraft and vehicle design
EE/CS 3176
John R. Hoffman
(Lockheed Martin Missiles
and Space Company, Inc.)
EE/CS 3180
11:20a11:40a
Team 5: Size and shape
comparisons from noisy,
unlabeled, incomplete
configurations of landmarks in
three-dimensional space
Mark A. Stuff (General
Dynamics Advanced
Information Systems)
EE/CS 3180
11:40a12:00p
Team 6: Wavelength assignment
and conversion in optical
networking
Lisa Zhang (Lucent
Technologies Bell
Laboratories)
EE/CS 3180
12:00p1:30p
Lunch
Lind Hall
400
1:30p4:30p
afternoon - start work on projects
Break-out
Rooms
Thursday, August 9
All
Day
Students work on the projects.
Mentors guide their groups through
the modeling process, leading
discussion sessions, suggesting
references, and assigning work.
Friday, August 10
All
Day
Students work on the projects.
Mentors guide their groups through
the modeling process, leading
discussion sessions, suggesting
references, and assigning work.
Saturday, August 11
All
Day
Students and mentors work on the
projects.
Sunday, August 12
All
Day
Students and mentors work on the
projects.
Monday, August 13
Break-out
Rooms
Break-out
Rooms
Break-out
Rooms
Break-out
Rooms
9:30a9:50a
Team 6 Progress Report
EE/CS 3180
9:50a10:00a
Team 3 Progress Report
EE/CS 3180
10:10a10:30a
Team 2 Progress Report
EE/CS 3180
10:30a11:00a
Break
EE/CS 3176
11:00a11:20a
Team 4 Progress Report
EE/CS 3180
11:20a11:40a
Team 5 Progress Report
EE/CS 3180
11:40a12:00p
Team 1 Progress Report
EE/CS 3180
12:00p2:00p
Picnic
UofM East
River Flats
Park
Tuesday, August 14
All
Day
Students and mentors work on the
projects.
Wednesday, August 15
All
Day
Students and mentors work on the
projects.
Thursday, August 16
All
Day
Students and mentors work on the
projects.
Friday, August 17
Breakout
Rooms
Breakout
Rooms
Breakout
Rooms
9:00a9:30a
Team 5 Final Report
EE/CS 3180
9:30a10:00a
Team 1 Final Report
EE/CS 3180
10:00a10:30a
Team 4 Final Report
EE/CS 3180
10:30a11:00a
Break
EE/CS 3176
11:00a11:30a
Team 2 Final Report
EE/CS 3180
11:30a12:00p
Team 6 Final Report
EE/CS 3180
12:00p12:30p
Team 3 Final Report
EE/CS 3180
12:30p2:00p
Pizza party
Lind Hall
400
Event Legend:
MM8.8-17.07
Mathematical Modeling in Industry XI - A Workshop for Graduate Students
SP7.23-8.3.07
Classical and Quantum Approaches in Molecular Modeling
Abstracts
Hoda Abdel-Aal Bettley
(University of Manchester)
Molecular modelling the structure and
dynamics of alginate oligosaccharides
Abstract: Same abstract as the 7/24 poster session.
Natalia Alexandrov (NASA
Langley Research Center)
Team 1: Supersonic design
Abstract: Designing affordable, efficient, quiet supersonic passenger aircraft has been
under investigation for many years. Obstacles to designing such aircraft are also many,
both in fundamental physics and in computational science and engineering. The problem
of design is multidisciplinary in its nature and the goals of the constituent disciplines that
govern the behavior of an aircraft are often at odds. In particular, aircraft that yields low
sonic boom may not be attractive aerodynamically, while aerodynamically optimized
aircraft may produce unacceptable sonic boom. One of the essential difficulties in using
direct optimization methods to design for low boom and low drag is in modeling the design
problem. For instance, it is not clear what objective functions to use.
Some Early Boom Shaping Developments (Ferri, 1969)
This project will use simple aerodynamic and sonic boom models to examine modeling of
the design problem itself. We will attempt to establish a meaningful direct functional
dependence between the shape of the aircraft and aerodynamic and noise quantities of
interest by studying the sensitivity of these quantities to changes in shape. We will
experiment with several direct multiobjective optimization problem formulations.
References:
1. Seebass, R., Argrow, B.; "Sonic Boom Minimization Revisited", AIAA Paper 98-2956
2. Shepherd, K.P., Sullivan, B.M.; "A Loudness Calculation Procedure Applied to
Shaped Sonic Booms", NASA Technical Paper 3134, 1991
3. Carlson, H.W., Maglieri, D.J.; "Review of Sonic Boom Generation Theory and
Prediction Methods", J. Acoust. Soc. Amer., 51, pp. 675-685 (1972)
4. Alonso, J.J., Kroo, I.M., Jameson, A. "Advanced Algorithms for Design and
Optimization of Quiet Supersonic Platform", 40th AIAA Aerospace Sciences Meeting
and Exhibit, AIAA Paper 2002-0144, Reno, NV, January 2002
5. Raymer, D.P.; "Aircraft Design: a Conceptual Approach", Third Edition, AIAA, 1999
Prerequisites:
Required: Scientific computing skills (Matlab or Fortran 90/95 or C), 1 semester in
nonlinear optimization
Desired: Some background in statistical modeling, numerical analysis, multiobjective
optimization
Keywords: multidisciplinary optimization, supersonic design, low boom, aerodynamic
optimization
Paul W. Ayers (McMaster
University)
Density-functional theory and its
generalizations: legendre transform,
constrained search, open problems
Abstract: The quantum many-electron problem is easy in principle (solve the N-electron
Schrödinger equation) and hard in practice (because the cost of numerical methods
typically grows exponentially with the number of variables). However, there are
simplifying features. First, the dimensionality can be reduced because electronic
Hamiltonians contain only 1-body and 2-body terms. (This leads to reduced density-matrix
methods.) Second, the dimensionality can be reduced because electrons are identical
particles: if you know everything about one electron, then you know everything about all of
the electrons. (This leads to electron-propagator theory and density-functional theory.)
There is a “catch.†Reducing the number of dimensions leads to other problems
associated with approximating the energy functional and/or associated with restricting the
domain of the variational procedure. Two powerful techniques for resolving these
difficulties are the Legendre transform and constrained-search formulations of density
functional theory. This talk will discuss these formulations, and show how they can be
extended to define "generalized" density-functional theories. I'll conclude with some of my
favorite open problems in density-functional theory.
Radu V. Balan (Siemens
Corporate Research, Inc.)
Team 2: 802.11 WLAN MAC layer modeling
Abstract: 802.11 Wireless Local Area Networks (WLANs) have become as ubiquitous as
Internet access for personal computers. The basic unit of a WLAN is composed of one
Access Point (AP), and several mobile stations (STAs), all forming a Basic Service Set
(BSS). A typical WLAN setup is depicted in Figure 1.
Figure 1: A typical Basic Service Set (BSS), with one AP, and several mobile stations.
The IEEE Standard governing WLANs describes two modes of operation: Distributed
Coordination Function (DCF), and Point Coordination Function (PCF). By and large,
chipset manufacturers implement only the DCF mode, and compatibility testing is done for
this mode exclusively. The DCF is a contention-based mechanism where each wireless
device (AP, or STA) competes for air time. More specifically, the 802.11 standard is
implemented as follows:
1. At regular intervals (typically hundreds of ms) the AP broadcasts a beacon signal,
which resets all devices internal clocks;
2. Assume a transmission opportunity ended at time t0. Depending on the status of the
internal Backoff counter (BCK) of the device, the following actions can take place:
{
{
If BCKr=0, and there is no activity on air for DIFS (Distributed Inter Frame
Spacing = 50us in 802.11b) time, then station starts transmitting its data
packet;
If BCK=0 and during the DIFS period there is activity on air then device
generates a random BCK between 0 and CW-1 (initially CW=CWmin = 16, in
802.11b); Then the following rules apply:
„
„
„
„
„
For each slot time (Ts) of medium inactivity, the BCK decrements;
The countdown is stopped whenever medium is busy, and the the
countdown is resumed only after a supplemental AIFS (Arbitration
Inter Frame Spacing, =DIFS in 802.11b) wait;
When BCK reaches 0, the device transmits its packet data;
If receiver (AP, or STA) receives successfully the packet, then it sends
back on the air an Acknowledgement (ACK) frame, after a SIFT (Short
Inter Frame Spacing = 10us) period after transmitter finishes its
transmission;
If transmitter receives the ACK correctly, then it assumes data was
received correctly, and transmission ends; On the other hand, if ACK is
not broadcast, or the transmitter does not receive correctly the ACK,
then it assumes the transmission was not successful, and the following
rules apply:
1. If current number of retransmissions has not reached a max
threshold, then increment the Number of Retransmissions
counter
2. If CW<= CWmax, then CW doubles;
3. A new random BCK is generated between 0 and CW-1;
4. Transmission process is restarted from step b. above
{
When transmission ends, a post-backoff mechanism is implemented, by
which a random BCK between 0 and CWmin-1 is generated, and a virtual
countdown process is started obeying b.i and b.ii above.
These (somewhat simplified) rules govern the behavior of 802.11 devices. A big challenge
in WLAN research is in modeling such a system. The purpose of this research group is to
advance the current state-of-the-art model to allow for effective network control algorithm
design.
Description of the problem
Basically there are two distinct regimes, completely opposite from one another:
1. Deterministic Regime: when no collision happen, and the initial MAC instance time
are sufficiently far apart, then transmission happens in a deterministic mode. Such a
case may happen when only voice data (such as VoIP stations are connected to the
AP), or periodic transmitting stations are present. The deterministic regime analysis
gives an upper bound on system performance;
2. Stochastic Regime: once collisions happen, or medium is detected busy during a
packet arrival, the random generation of a Backoff counter happens, and the
contention-based mechanism kicks in.
The deterministic regime is used to compute maximal performance of a WLAN. In such a
case, performance may be superior even to the PCF mode, where AP acts as a transmission
controller. However, in highly loaded networks, collisions are quite frequent, and the
stochastic regime is more likely. Several works proposed stochastic models for this regime.
Each work concerned one feature or another of network behavior. Bianchi [1] was the first
to propose the use of Markov Chain in modeling the saturation regime of a WLAN. Since
his paper, several others considered saturation, and non-saturation modeling of WLANs,
increasing the model complexity, and taking into account more phenomena observed in
experimental setups. In particular [2] represents a relatively good stochastic model for
several regimes of WLAN. A somewhat refined diagram is presented in Figure 2. However
the current state-of-the-art model is not sufficient for several reasons:
1. It does not take into account the deterministic regime, nor does the performance
converge to that upper bound;
2. The Markovianity assumption is not always justifiable; is it possible to introduce a
deterministic-stochastic hybrid model?
3. Subsequent improvements of the standard are not yet captured by the current
model; in particular the 802.11n draft introduces new MAC mechanisms.
The goal of this research group is to address one or more of the issues above. Ideally,
students should have:
- familiarity with basic stochastic modeling concepts (such as Markov chains)
- familiarity with use of network simulation software (such as ns2);
- familiarity with time-series data analysis software (such as perl, Matlab);
Figure 2: A Markov Chain Model for a WLAN device.
Bibliography
[1] G.Bianchi, Performance Analysis of the IEEE 802.11 Distributed Coordination
Function, IEEE Journal on Selected Areas of Communications, 18 (3), 2000, 535-547.
[2] P.E.Engelstad and O.N.Osterbo, Non-Saturation and Saturation Analysis of IEEE
802.11e EDCA with Starvation Prediction, MSWiM.05: Proceedings of the 8th ACM
international symposium on Modeling, analysis and simulation of wireless and mobile
systems, Montreal, Canada, 2005.
Axel D. Becke (Dalhousie
University)
Exchange and correlation in electronic
systems: the hole story
Abstract: Exchange and correlation effects in electronic systems are rigorously related to a
two-electron function called the exchange-correlation "hole". Modelling of the hole in real
space is a powerful route to development and refinement of exchange and correlation
functionals in DFT. We have developed real-space models of all correlation types of
importance in chemical physics (dynamical, nondynamical, and dispersion) and these will
be reviewed.
Vivaldo L. Campo
(University of Minnesota Twin
Cities)
Method for determination of Hubbard model
phase diagram from optical lattice
experiments by two parameter scaling
Abstract: Same abstract as the 7/24 poster session.
James R. Chelikowsky
(University of Texas)
Real space pseudopotentials applied to
nanoscale systems
Abstract: One of the most challenging issues in materials physics is to predict the
properties of matter at the nanoscale. In this size regime, new structural and electronic
properties exist that resemble neither the atomic, nor solid state. These altered properties
can have profound technological implications. Theoretical methods to address such issues
face formidable challenges. Nanoscale systems may contain thousands of electrons and
atoms, and often possess little symmetry. I will illustrate some recent advances in this area
based on new computational methods and apply these techniques to systems ranging from
clusters of a few dozen atoms to quantum dots containing thousands of atoms. Recent
publications: Y. Zhou, Y. Saad, M.L. Tiago, and J.R. Chelikowsky: "Parallel Self-ConsistentField Calculations via Chebyshev-Filtered Subspace Acceleration,'' Phys. Rev. E 74, 066704
(2006). M.L. Tiago, Y. Zhou, M.M.G. Alemany, Y. Saad, J.R. Chelikowsky: "The Evolution
of Magnetism in Iron from the Atom to the Bulk,'' Phys. Rev. Lett. 97, 147201 (2006). M.
Lopez del Puerto, M.L. Tiago, and J.R. Chelikowsky: "Excitonic effects and optical
properties of passivated CdSe clusters,'' Phys. Rev. Lett. 97, 096401 (2006).
Matteo Cococcioni
(University of Minnesota Twin
Cities)
A consistent, linear-response approach to
LDA+U
Abstract: Hubbard U-corrected DFT functionals have been very successful in describing
several strongly-correlated systems for which "standard" approximations to DFT fail.
Unfortunately no explicit expression exists for the effective electronic interaction
parameter (the Hubbard U) contained in the corrective ("+U") functional and
semiempirical estimates have been often used to determine its value. In this talk, after a
general introduction to the LDA+U method, I will present our linear response approach to
the evaluation of the Hubbard U [1]. Within this approach the on-site electronic coupling is
computed from the response of the considered system to a shift in the potential acting on
its correlated atomic states. Specifically, it is evaluated as the difference between the
inverse of the bare and fully interacting response matrices. The U we obtain thus
corresponds to the effective (atomically averaged) interaction between electrons that are
located on the same site. In this way the strength of the "+U" correction is consistently
evaluated from the same DFT scheme we aim to correct; the LDA+U is transformed in a
completely ab-initio method with no need for any empirical evaluation of the effective
coupling. The results are also largely independent on the choice of the localized orbitals:
the same occupation matrix that enters the expression of the "+U" correction is
consistently used to compute the effective interaction parameter. With this approach we
successfully studied the structural, electronic, chemical and electrochemical properties of
several transition metals compounds. Examples of applications will include minerals in the
Earth's interior [1], cathode materials for next-generation lithium-ion batteries [2] and
catalysis reactions on molecules [3]. [1] M. Cococcioni and S. de Gironcoli, PRB (2005). [2]
F. Zhou, M. Cococcioni, A. C. Marianetti, D. Morgan and G. Ceder, PRB (2004). [3] H. J.
Kulik, M. Cococcioni, D. Scherlis and N. Marzari, PRL (2007).
Ismaila Dabo
Real-space corrections for electrostatic
(Massachusetts Institute of
Technology)
interactions in periodic boundary conditions
Abstract: Joint work with Boris Kozinsky (Department of Physics, MIT), Nicholas E.
Singh-Miller, and Nicola Marzari (Department of Materials Science and Engineering,
MIT). We address periodic-image errors arising from the use of periodic boundary
conditions to describe systems that do not exhibit full three- dimensional periodicity. We
show that the difference between the periodic potential, straightforwardly obtained from a
Fourier transform, and the exact potential can be characterized analytically. In light of this
observation, we present an efficient real-space method to correct periodic-image errors,
demonstrating that exponential convergence of the energy with respect to cell size can be
achieved in practical periodic boundary-condition calculations. Comparing the method
with existing schemes, we find that it is particularly advantageous for studying charged
systems and systems exhibiting partial periodicity.
Ernest R. Davidson
(University of Washington)
Theoretical description of electrons in single
molecule magnets
Abstract: Single molecule magnets are usually based on transition metals with partially
filled d shells. When several metal centers are involved this leads to molecules with many
single occupied orbitals coupled into an intermediate spin state. Conventional methods of
quantum chemistry are not able to deal with this situation, so the Heisenberg model
hamiltonian is often used with parameters estimated from DFT calculations. Practical as
well as logical problems with this approach will be discussed. Some of the difficulties with
treating exchange in DFT for open shell systems will be presented.
Kaushik Dayal (University
of Minnesota Twin Cities)
Objective structures and their applications
Abstract: Same abstract as the 7/24 poster session.
Amélie Deleurence (É
cole Nationale des Ponts-etChaussées (ENPC))
Modelling of local defects in crystals
Abstract: Same abstract as the 7/24 poster session.
Jean-Luc Fattebert
(Lawrence Livermore National
Laboratory)
Real-space finite difference method for O(N)
first-principles molecular dynamics with
plane waves accuracy
Abstract: Representing the electronic structure in Density Functional Theory (DFT) by a
set of localized wave functions discretized on a real-space mesh essentially leads to a linear
scaling of the computational cost with the size of the physical system. This can be achieved
by formulating the DFT energy functional in terms of general non-orthogonal orbitals
which are then optimized under localization constraints (spatial confinement). Multigrid
preconditioning and a block version of Anderson's extrapolation scheme are used to
accelerate convergence towards the ground state. For localization regions --- constraints -- large enough, one can reduce truncation error to a value smaller than discretization error
and achieve the level of accuracy of a Plane Waves calculation. Accuracy is improved by
allowing for flexible localization regions that can adapt to the system. This also reduces
problems with local minima and enables energy conserving Born-Oppenheimer molecular
dynamics simulations. Our implementation of this approach scales on hundreds of
processors and becomes competitive with Plane Waves codes around 500 atoms.
References:
[1] J.-L. Fattebert and F. Gygi, Phys. Rev. B 73, 115124 (2006)
[2] J.-L. Fattebert and F. Gygi, Comput. Phys. Comm. 162, 24 (2004) This work was
performed under the auspices of the U.S. Department of Energy by University of California
Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
Seyed-Alireza Ghasemi
(Universität Basel)
A systematic method to explore possible
silicon tip structures used in AFM
Abstract: Same abstract as the 7/24 poster session.
Stefan Goedecker
(Universität Basel)
Wavelets for electronic structure calculations
and electrostatic problems
Abstract: Wavelets are a systematic localized basis set that is well suited for representing
Kohn-Sham orbitals. I will explain the algorithms that we are using in our new ABINIT
wavelet program and show perfomance results. In the second part I will show how scaling
functions can be used to solve electrostatic problems both for continuous and discrete
charge distributions under various boundary conditions.
Gary B. Green (The
Aerospace Corporation)
Team 3: Associating earth-orbiting objects
detected by astronomical telescopes
Abstract: Project description: Astronomical telescopes detect the passage of an earthorbiting object as a streak in an image. Over a period of months, it is possible that many
objects will pass through the field of view, some appearing more than once. There are
estimates of 100,000 objects in orbit that might be detected by high resolution telescopes.
A large field of view telescope may see 100 streaks a night. Most of these objects are space
debris that pose a hazard to operational satellites. There is keen interest within the space
community to discover and track all these objects.
If the telescope sensor is properly instrumented, it is possible to obtain time-tagged pairs
of angles that relate the space object position to the sensor. With enough angle pairs, it is
possible to estimate the position and velocity (the state) of the object, along with estimates
of the uncertainties of these parameters. The workshop problem is to develop techniques
to identify all the streaks made by each object. Streaks created by an object must somehow
be associated with one another and disassociated from those made by other objects. One
solution approach treats the state data as vectors in R6 and uses statistical clustering
techniques for the association. A variation on this approach addresses physical properties
of the orbits, sorting according to those least likely to change with small state variations.
Regardless of the approach, there are several interesting aspects to the problem. Automatic
streak detection is required, with transform techniques of interest. Orbit mechanics are
essential to effective state estimation as well as clustering techniques. In addition,
traditional clustering techniques are computationally taxing. A related problem is
identification of asteroids that might pose a hazard to planet earth. References:
Vallado, David A., Fundamentals of Astrodynamics and Applications, Edition 2, Microsoft
Press, 2004; Milani, Andrea, "Three Short Lectures on Identifications and Orbit
Determination," http://copernico.dm.unipi.it/~milani/preprints/preprint.html, 2006;
Kaufman, L. and Rousseeuw, P., Finding Groups in Data - An Introduction to Cluster
Analysis. Wiley Interscience 2005
Prerequisites:
Required: computing proficiency demonstrated by knowledge of at least one compiler, one
semester differential equations, one semester statistics
Desired: one semester numerical analysis, familiarity with orbit mechanics and estimation
theory.
Keywords: orbit mechanics, astronomical telescopes, statistical clustering
The Pan-starrs telescope on Mount Haleakela in Hawaii will be used, among other tasks, to
search for asteroids. However, using its 1.4 billion pixel sensor, it will also detect earthorbiting objects.
Nicholas M. Harrison
(Imperial College London)
Novel materials for quantum computing
Abstract: The controlled transport of spin polarised electrons on a 1 nanometre length
scale is a realistic prospect and could be the basis for new multifunctional devices with a
component density an order of magnitude higher than current VLSI technology. The
fundamental materials chemistry challenge is to produce a nano-structured semiconductor
that is ferromagnetic at room temperature. Ideally the electronic and magnetic properties
need to be robust but tunable through control of composition and structure. The results of
recent high quality theoretical calculations on a number of pure carbon materials will be
presented. A novel mechanism for long range magnetic coupling in extended pi-bonded
systems will be discussed and documented with explicit calculations on graphene ribbons
and defective graphene sheets. A putative ordered defect phase which gives rise to a
semiconducting ground state that is ferromagnetic at room temperature will be presented.
It will also be shown that the band gap and magnetic coupling may be controlled by
varying the defect density.
Pieter Hendrickx
(University of Ghent (UG))
Conformational reinvestigation of two cyclic
pentapeptides: to a generic approach in drug
development
Abstract: Same abstract as the 7/24 poster session.
John R. Hoffman
(Lockheed Martin Missiles
and Space Company, Inc.)
Team 4: High dimensional, nonlinear, nonconvex optimization problems in the area of
aircraft and vehicle design
Abstract: Presently, when a physics motivated vehicle designer explores vehicle designs for
a new concept, he is often faced with an enormous range of choices and constraints. For an
example, an aircraft designer has Aircraft shape, fuel type, and engine as his main free
variables. While his main constraints are dictated by the laws of physics (weight, size,
power, lift, and stall). Additionally, he has his objective which is typically some
combination/subset of acceleration, maneuverability, range, endurance, payload capacity
(size, weight and power), max and min speeds, manufacturing cost, maintainability,
reliability, development cost, takeoff length, landing length, noise footprint and other
items.
I am interested in examining the following problem: Given a set of performance objectives,
how does one determine the space of designs available to the designer and find the optimal
designs? How does the designer best visualize this space of options? Because he doesn't
want just "the" answer, he wants to understand many aspects of the answer. While I'm
interested in the general vehicle design problem, we will focus on aircraft design using a
baseline tool that is to be determined as a concrete example with which we can test our
ideas.
Jürg Hutter (Universität
Zürich)
Efficient Kohn-Sham density functional
calculations using the Gaussian and plane
waves approach
Abstract: The Gaussian and plane waves (GPW) approach combines the description of the
Kohn-Sham orbitals as a linear combination of Gaussian functions with a representation of
the electron density in plane waves. The unique properties of Gaussian functions allow for
a fast and accurate calculation of the density in the plane wave basis. The plane wave
representation of the density leads to an easy solution of Poisson's equation and thereby a
representation of the electrostatic potential. Matrix elements of this potential can be
calculated using the same methods. The auxiliary representation of the density is further
used in the calculation of the exchange-correlation energy and potential. The resulting
approach scales O(N log N) in the number of electrons and has many additional interesting
features, namely, a small prefactor, early onset of linear scaling, and a nominal quadratic
scaling in the basis set size for fixed system size. The GPW method is combined with a
direct optimization of the subspace of occupied Kohn-Sham orbitals using an orbital
transformation (OT) method. A variation of this method has recently been implemented
that only requires matrix multiplications. The method combines a small prefactor with
efficient implementation on parallel computers, thereby shifting the break even point with
linear scaling algorithms to much larger systems. A strategy to combine the OT method
with sparse linear algebra will be outlined.
Olexandr Isayev (Jackson
State University)
An ab initio molecular dynamics simulation
of solid CL-20: mechanism and kinetics of
thermal decomposition
Abstract: Same abstract as the 7/24 poster session.
Changho Kim (Korea
Advanced Institute of Science
and Technology (KAIST))
Numerical method for solving stochastic
differential equations with non-Gaussian
noise
Abstract: Same abstract as the 7/24 poster session.
David Langreth (Rutgers
University)
Van der Waals interactions in density
functional theory
Abstract: To understand biostructures, soft matter, and other abundant sparse systems,
one must account for both strong local atomic bonds and weak nonlocal van der Waals
(vdW) forces between atoms which are sometimes separated by empty space. A fully
nonlocal density functional, vdW-DF [1,3], now including a self-consistent potential [2,3],
will be described. It has had a number of promising applications [3], some of which will be
presented, including polymer crystals, metal-organic-framework structures, and nucleic
acids. [1] Phys. Rev. Lett. 92, 246401 (2004); [2] cond-mat/0703442v1; [3] Much of the
vdW-DF work has been a Chalmers-Rutgers collaboration.
Arash A. Mostofi
(University of Cambridge)
Linear-scaling density-functional
calculations with plane-waves
Abstract: A number of reasons have resulted in plane-waves becoming one of the basis sets
of choice for simulations based on density-functional theory, for example: the kinetic
energy operator is diagonal in momentum space; quantities are switched efficiently
between real space and momentum space using fast-Fourier transforms; the atomic forces
are calculated by straightforward application of the Hellmann-Feynman theorem; the
completeness of the basis is controlled systematically with a single parameter. The
resulting simulations require a computational effort which scales as the cube of the
system-size, which makes the cost of large-scale calculations prohibitive. For this reason
there has been much interest in developing methods whose computational cost scales only
linearly with system-size and hence bringing to bear the predictive power of densityfunctional calculations on nanoscale systems. At first sight the extended nature of planewaves makes them unsuitable for representing the localised orbitals of linear scaling
methods. In spite of this, we have developed ONETEP (Order-N Electronic Total Energy
Package), a linear-scaling method based on plane-waves which overcomes the above
difficulty and which is able to achieve the same accuracy and convergence rate as
traditional cubic-scaling plane-wave calculations.
Alexey Neelov (Universität
Basel)
Particle-Scaling function (P3S) algorithm for
electrostatic problems in free boundary
conditions
Abstract: Same abstract as the 7/24 poster session.
Christian Ochsenfeld
(Eberhard-Karls-Universität
Tübingen)
A Linear-scaling AO-based MP2 method for
large molecules by rigorous integral
estimates
Abstract: Describing electron correlation effects for large molecules is a major challenge
for quantum chemistry due to the strong increase of the computational effort with
molecular size. In order to overcome this limitation, we present a rigorous method based
on an AO-formulation of MP2 theory, which allows to avoid the conventional fifth-power
scaling of MO-MP2 theory and to reduce the scaling to linear without sacrificing accuracy.
The key feature of our method are multipole-based integral estimates (MBIE), which
account for the 1/R coupling in two-electron integrals and allow to rigorously preselect
integral products in AO-MP2 theory. Here, the magnitude of products decays at least with
1/R**4, so that a linear-scaling behavior can be achieved by numerical thresholding
without sacrificing any accuracy. The linear-scaling increase of the computational effort is
reached much earlier than for HF or DFT approaches: e.g. the exact behavior of products
indicates a scaling of N**1.0 from one to two DNA base-pairs for a 6-31G* basis. The
number of significant elements in the pseudo-density matrices and of shell pairs hints to a
very similar linear-scaling behavior for larger basis sets studied up to cc-pVQZ. First
results of a preliminary implementation show that an early crossover to conventional MP2
schemes below two DNA base pairs is observed, while already for a system with four DNA
base pairs wins are at least a factor of 16.
Shantanu Roy (Universität
Basel)
A Bell-Evans-Polanyi principle for molecular
dynamics trajectories and its implications for
global optimization
Abstract: Same abstract as the 7/24 poster session.
Prasanjit Samal (University
of Minnesota Twin Cities)
Uniqueness of the density-to-potential
mapping in excited-state density-functional
theory
Abstract: Same abstract as the 7/24 poster session.
Andreas Savin
(Université de Paris VI
(Pierre et Marie Curie))
Dealing with spatial regions
Abstract: Chemists are used to see molecules in three dimensions, and think of the
molecular properties often related to specific regions of space. This is a good source of
inspiration for theoretical methods, but efficient algorithms for a mathematical treatment
of models needing, e.g., integration in arbitrary, flexible regions in 3D are still needed.
Viktor N. Staroverov
(University of Western
Ontario)
Kohn-Sham methods for implicit density
functionals
Abstract: Density functional theory calculations with a certain class of approximations to
the Kohn-Sham exchange-correlation energy require an indirect evaluation of the
functional derivative of an implicit functional. Although the formal prescription for
obtaining this derivative is known, there are fundamental pitfalls in its practical
implementation using discrete basis set representations of the operators. We discuss
several pragmatic solutions to this problem and compare their advantages in various
applications.
Gabriel Stoltz (École
Nationale des Ponts-etChaussées (ENPC))
Local exchange potentials: A mathematical
viewpoint
Abstract: Work in collaboration with Eric Cancès (CERMICS), Ernest R. Davidson
(Department of Chemistry, University of Washington), Artur F. Izmaylov, Gustavo
Scuseria and Viktor N. Staroverov (Department of Chemistry, Rice University). This work
reviews and presents in a unified fashion several well-known local exchange potentials,
such as the Slater potential, Optimized Effective Potentials and their approximations (KLI,
CEDA local potentials) and the recently proposed Effective Local Potential. We provide
alternative derivations of some of these well-known potentials, mainly based on variational
arguments (the local exchange potential being defined as the best approximation of the
nonlocal Hartree-Fock operator in some least square sense). The remaining potentials are
approximate solutions of the so-called OEP integral equation, and can be recovered
through convenient approximations of the resolvent of the Hamiltonian operator.
Mark A. Stuff (General
Dynamics Advanced
Information Systems)
Team 5: Size and shape comparisons from
noisy, unlabeled, incomplete configurations
of landmarks in three-dimensional space
Abstract: Traditional non-invasive sensing technologies have generated information about
only one or two dimensional projections of objects of interest. But the use of arrays of
sensor components, and opportunities to rapidly move such arrays around objects of
interest are enabling the practical generation of many forms of three-dimensional data. For
example, in acoustics there has been steady progression from one-dimensional echo trains,
to two-dimensional acoustic images, to modern three-dimensional reconstructions, on
scales from ultrasound wavelengths to global seismic surveys. Similarly, three-dimensional
tomographic reconstructions from x-rays are now commonly used to resolve ambiguities in
traditional two-dimensional x-ray images.
As more three-dimensional data becomes available, the value of automatic tools for
utilizing such data increases. Several desired applications need methods by which to
automate the finding of correspondences between three-dimensional data sets. These
three-dimensional data sets frequently share many geometric characteristics, but also have
significant differences, due to differences in data collection geometries, changes in sensor
capabilities, temporal changes in the object of interest, and noise in the data.
One approach to finding unknown coordinate transformations, which are needed to align
multi-dimensional data sets, is to require an expert to examine each set and label certain
common landmarks. If sufficient landmarks, having the same unique labels can be found
in both sets, the three-dimensional coordinates of the landmarks enable the coordinate
transformation to be estimated. This is like aligning images of faces, by first extracting the
coordinates the tips of the noses, the left corners of the mouths, the bases of the right
earlobes, etc.
But when no prior expertise is available, we need methods of estimating the
transformation from set of automatically generated coordinates of 'interesting' locations
(unlabeled landmarks). We expect that a significant subset of corresponding unlabeled
landmarks may exist somewhere in the data set to which we need to compare. To solve our
alignment problems, we need to devise automated methods to robustly find a pair of large
subsets from a pair of sets of unlabeled landmarks, such that the subsets have similar
geometric characteristics.
Does there exist a rigid motion mapping the configuration of red points onto a
subset of the blue points? If so, what is the blue subset, and what is the rigid
motion? If not, how much deformation of the red configuration is needed to make
it so?
In principle, these problems can be solved by exhaustively comparing every possibility, but
the level of effort grows exponentially fast with the number of landmarks. Our goal will be
to find and test new approaches to this problem, seeking to devise algorithms which are
robust and far more efficient.
References:
1. Oliver Faugeraus, Three-Dimensional Computer Vision, MIT Press, 2001
2. Ian L. Dyrden, Kanti V. Mardia, {Statistical Shape Analysis}, Wiley, 1998
3. D. G. Kendall, D. Barden, T. K. Carne, H. Le, Shape and Shape Theory, Wiley Series
in Probability and Statistics, 1999
4. Gene H. Golub, Charles Van Loan, Matrix Computations, Johns Hopkins University
Press, 1996
Prerequisites:
Basics of linear algebra and matrix theory, basic computer programming skills, elementary
Euclidean geometry
Desired: Ability to bring relevant ideas from one or more of geometry, invariant theory,
optimization theory, graph theory, combinatorics, or something else.
Michael Teter (Cornell
University)
Precision problems in density functional
development for better molecular modeling
Abstract: Same abstract as the 7/24 poster session.
Walter Thiel ( Max-PlanckInstitut für
Kohlenforschung)
QM/MM studies on enzymes
Abstract: The lecture will report on recent progress in combined quantum mechanical /
molecular mechanical (QM/MM) approaches for modeling chemical reactions in large
biomolecules. After a brief outline of the theoretical background and the chosen strategy
[1], we address free-energy QM/MM calculations as well as the use of accurate correlated
ab initio QM methods in QM/MM work. Case studies are presented for biocatalysis by phydroxybenzoate hydroxylase [2,3] and cytochrome P450cam [4,5]. [1] H. M. Senn, W.
Thiel, Top. Curr. Chem. 2007, 268, 173-290.
[2] H. M. Senn, S. Thiel, W. Thiel, J. Chem. Theory Comput. 2005, 1, 494-505.
[3] F. Claeyssens, J. N. Harvey, F. R. Manby, R. Mata, A. J. Mulholland, K. E. Ranaghan,
M. Schuetz, S. Thiel, W. Thiel, H.-J. Werner, Angew. Chem. Int. Ed. 2006, 45, 6856-6859.
[4] J. C. Schoeneboom, F. Neese, W. Thiel, J. Am. Chem. Soc. 2005, 127, 5840-5853.
[5] A. Altun, V. Guallar, R. A. Friesner, S. Shaik, W. Thiel, J. Am. Chem. Soc. 2006, 128,
3924-3925.
Donald G. Truhlar
(University of Minnesota Twin
Cities)
New density functionals: a meta GGA and
three hybrid meta GGAs with good
performance for thermochemistry,
thermochemical kinetics, noncovalent
interactions, and spectroscopy
Abstract: In work carried out with Yan Zhao, we have developed a suite of hybrid meta
exchange-correlation functionals, including three hybrid meta generalized gradient
approximations (hybrid meta GGAs) called M06, M06-2X, and M06-HF and one local
meta GGA, called M06-L. The M06 and M06-L functionals are parametrized including
both transition metals and nonmetals, whereas the M06-2X and M06-HF functionals are
high-nonlocality functionals with double the amount of nonlocal exchange (2X) as
compared to M06 and 100% Hartree-Fock exchange, respectively, and they are
parametrized only for nonmetals. We have assessed these four functionals by comparing
their performance to that of other functionals and other theoretical results for 403
accurate energetic data in 29 diverse databases, including ten databases for
thermochemistry, four databases for kinetics, eight databases for noncovalent interactions,
three databases for transition metal bonding, one database for metal atom excitation
energies, and three databases for molecular excitation energies. We have also tested the
performance of these 17 methods for three databases containing 40 bond lengths and for
databases containing 38 vibrational frequencies and 15 vibrational zero point energies. We
recommend the M06-2X functional for applications involving main-group
thermochemistry, kinetics, noncovalent interactions, and electronic excitation energies to
valence and Rydberg states. We recommend the M06 functional for applications in
organometallic and inorganometallic chemistry and for noncovalent interactions. We
recommend the M06-HF functional for all main-group spectroscopy, and we recommend
the local M06-L functional for calculations on large systems, where a local functional is
very cost efficient. An overview of this work will be presented.
Erkan Tüzel (North
Dakota State University)
Mesoscopic model for the fluctuating
hydrodynamics of binary and ternary
mixtures
Abstract: Same abstract as the 7/24 poster session.
Yan Alexander Wang
(University of British
Columbia)
Orbital-Corrected Orbital-Free density
functional theory
Abstract: Density functional theory (DFT) has been firmly established as one of the most
widely used first-principles quantum mechanical methods in many fields. Each of the two
ways of solving the DFT problem, i.e., the traditional orbital-based Kohn-Sham (KS) and
the orbital-free (OF) [1] schemes, has its own strengths and weaknesses. We have
developed a new implementation of DFT, namely orbital-corrected OF-DFT (OO-DFT) [2],
which coalesces the advantages and avoids the drawbacks of OF-DFT and KS-DFT and
allows systems within different chemical bonding environment to be studied at a much
lower cost than the traditional self-consistent KS-DFT method. For the cubic-diamond Si
and the face-centered-cubic Ag systems, OO-DFT accomplishes the accuracy comparable
to fully self-consistent KS-DFT with at most two non-self-consistent iterations [2] via
accurately evaluating the total electronic energy before reaching the full self-consistency
[2-5]. Furthermore, OO-DFT can achieve linear scaling by employing currently available
linear-scaling KS-DFT algorithms and may provide a powerful tool to treat large systems of
thousands of atoms within different chemical bonding environment much more efficiently
than other currently available linear-scaling DFT methods. Our work also provides a new
impetus to further improve OF-DFT method currently available in the literature. [1] Y. A.
Wang and E. A. Carter, in Theoretical Methods in Condensed Phase Chemistry, edited by
S. D. Schwartz (Kluwer, Dordrecht, 2000), p. 117. [2] B. Zhou and Y. A. Wang, J. Chem.
Phys. 124, 081107 (2006). (Communication) [3] “An Accurate Total Energy Density
Functional,†B. Zhou and Y. A. Wang, Int. J. Quantum Chem. (in press). [4] “The
Total Energy Evaluation in the Strutinsky Shell Correction Method,†B. Zhou and Y. A.
Wang, J. Chem. Phys. (in press). [5] “Accelerating the Convergence of the Total Energy
Evaluation in Density Functional Theory Calculations,â€
Chem. Phys. (submitted).
Renata Wentzcovitch
(University of Minnesota Twin
Cities)
B. Zhou and Y. A. Wang, J.
Materials at ultra-high PTs: the coming of age
of planetary materials theory
Abstract: DFT based approaches permit the determination of structural and
thermodynamic properties of materials with sufficiently useful accuracy to allow one to
address states and properties of planetary interiors. I will make a brief review of areas in
mineral physics problems that have recently experienced much progress and are shedding
light on fundamental problems in planetary sciences. Research supported by NSF/EAR
and NSF/ITR programs.
Tomasz A. Wesolowski
(Université de Genève)
Orbital-free embedding potential: properties,
approximations, and the use in computer
simulations to couple quantum chemical and
classical levels of description
Abstract: Practical applications of one-electron equations for embedded orbitals (Eqs. 2021 in Ref. [1]) hinge on the availability of explicit density functionals to approximate
adequately the exchange-correlation energy and the non-additive kinetic energy. The
former quantity is defined as in the Kohn-Sham formulation of density functional theory,
whereas the latter one arises from the use of orbitals (/embedded orbitals/) for only a
selected component of the total electron density in the applied formal framework. The
quality of the /shifts /of the electronic properties of a chemical species due to its
condensed phase environment calculated by means of Eqs. 20-21 of Ref. [1] is determined
by the kinetic-energy-functional dependent component of the total effective potential. In
this work, our recent works concerning the development and testing of systemindependent approximations this component of the embedding potential. and selected
representative applications to study details of the electronic structure of embedded
systems in condensed phase [2,3] are reviewed. [1] T.A. Wesolowski & A. Warshel, /J.
Phys. Chem./ *97* (1993), 8050.
[2] M. Zbiri, C. Daul, and T.A. Wesolowski, /Journal of Chemical Theory and
Computation / *2* (2006) 1106.
[3] J. Neugebauer, C.R. Jacob, T.A. Wesolowski, E.J. Baerends, /J. Phys. Chem. A./ *109*
(2005) 7805.
Dexuan Xie (University of
Wisconsin)
New numerical algorithms and software for
minimizing biomolecular potential energy
functions
Abstract: Same abstract as the 7/24 poster session.
Lisa Zhang (Lucent
Technologies Bell
Laboratories)
Team 6: Wavelength assignment and
conversion in optical networking
Abstract: Today's optical telecommunication networks carry audio, video and data traffic
over fiber optics at extremely high bit rates. The design of such networks encompasses a
range of challenging combinatorial optimization problems. Typically, these problems are
computationally hard even for restricted special cases. In this project we study how to
assign wavelengths and place equipment so as to carry a set of traffic demands in large
scale optical networks.
Our design problems are motivated by a popular optical technology called Wavelength
Division Multiplexing (WDM). In this setting each fiber is partitioned into a fixed number
of wavelengths and demands sharing a common fiber must be transported on distinct
wavelengths. A demand stays on the same wavelength along its routing path as much as
possible. When this is infeasible, we can either deploy an extra fiber for the demand to
continue on the same wavelength; or place a wavelength converter for the demand to
continue on a different wavelength. Both options incur cost. One objective is to assign
wavelengths and place converters in an advantageous way so as to minimize the total cost.
In this project we explore algorithms and heuristics for assigning wavelengths and placing
converters. The goals include studying the tradeoff between optimality and complexity and
understanding the gap between theoretical bounds and practical performance.
References:
[1] Matthew Andrews and Lisa Zhang, Complexity of Wavelength Assignment in Optical
Network Optimization. (Please see Section VI.) Proceedings of IEEE INFOCOM 2006.
Barcelona, Spain, April 2006. http://cm.bell-labs.com/~ylz/2006.coloring4.pdf
[2] C. Chekuri, et al. Design Tools for Transparent Optical Networks. Bell Labs Technical
Journal. Vol. 11, No. 2, pp. 129-143, 2006.
Prerequisite:
Required: One semester of algorithms; One semester of theory of computing; One
semester of programming.
Desired: Knowledge of Python and CPLEX.
Keywords: Analysis of algorithms, combinatorial optimization, implementation of
heuristics
Visitors in Residence
Hoda Abdel-Aal
Bettley
University of Manchester
7/22/2007 8/3/2007
Nikhil Chandra
Admal
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Haseena Ahmed
Iowa State University
8/7/2007 8/17/2007
Natalia
Alexandrov
NASA Langley Research Center
8/7/2007 8/18/2007
Jungha An
University of Minnesota Twin Cities
9/1/2005 8/31/2007
Douglas N.
Arnold
University of Minnesota Twin Cities
7/15/2001 8/31/2008
Donald G.
Aronson
University of Minnesota Twin Cities
9/1/2002 8/31/2007
Nii Attoh-Okine
University of Delaware
7/22/2007 8/3/2007
Paul W. Ayers
McMaster University
7/29/2007 8/3/2007
Radu V. Balan
Siemens Corporate Research, Inc.
8/7/2007 8/17/2007
Suman
Balasubramanian
Mississippi State University
8/7/2007 8/18/2007
Eric Barth
Kalamazoo College
7/22/2007 8/3/2007
Daniel J. Bates
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Axel D. Becke
Dalhousie University
7/31/2007 8/4/2007
Guy Bencteux
Électricité de France
7/22/2007 8/3/2007
Yermal Sujeet
Bhat
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Dan
Bolintineanu
University of Minnesota Twin Cities
7/24/2007 8/3/2007
Stephen Bond
University of Illinois at UrbanaChampaign
7/22/2007 8/3/2007
Sara Bonella
Scuola Normale Superiore
7/23/2007 8/3/2007
Sebastien
Boyaval
Ecole Nationale des Ponts et Chaussees
7/22/2007 8/4/2007
Richard J. Braun
University of Delaware
8/7/2007 8/18/2007
Leslie Button
Corning
7/22/2007 8/3/2007
Vivaldo L.
Campo
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Eric Cances
CERMICS
7/22/2007 8/4/2007
Michael Case
Clemson University
8/7/2007 8/19/2007
Matt
Challacombe
Los Alamos National Laboratory
7/29/2007 8/3/2007
Adam
Chamberlin
University of Minnesota Twin Cities
7/24/2007 8/3/2007
James R.
Chelikowsky
University of Texas
7/31/2007 8/3/2007
Qiang Chen
University of Delaware
8/7/2007 8/18/2007
Prince
Chidyagwai
University of Pittsburgh
8/7/2007 8/17/2007
Ting-Lan Chin
University of Minnesota Twin Cities
7/25/2007 8/3/2007
Jun Kyung
Chung
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Giovanni Ciccotti
Università di Roma "La Sapienza"
7/22/2007 8/3/2007
Matteo
Cococcioni
University of Minnesota Twin Cities
7/31/2007 8/3/2007
Christopher J.
Cramer
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Ismaila Dabo
Massachusetts Institute of Technology
7/27/2007 8/3/2007
Derek Jordan
Dalle
University of Minnesota Twin Cities
8/7/2007 8/18/2007
Bonhommeau
Andre David
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Ernest R.
Davidson
University of Washington
7/31/2007 8/4/2007
Kaushik Dayal
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Amélie
Deleurence
École Nationale des Ponts-etChaussées (ENPC)
7/22/2007 8/4/2007
Lisa Driskell
Purdue University
8/7/2007 8/17/2007
Ying Wai Fan
Emory University
8/7/2007 8/17/2007
Brendan Farrell
University of California
8/7/2007 8/18/2007
Jean-Luc
Fattebert
Lawrence Livermore National Laboratory
7/31/2007 8/3/2007
Olalla Nieto Faza
University of Minnesota Twin Cities
7/24/2007 8/3/2007
Laura Gagliardi
Université de Genève
7/22/2007 8/3/2007
Timur Gatanov
Harvard University
7/22/2007 8/3/2007
Seyed-Alireza
Universität Basel
7/22/2007 -
Ghasemi
8/4/2007
Manik Ghosh
Kyungpook National University
7/22/2007 8/3/2007
Stefan Goedecker
Universität Basel
7/31/2007 8/4/2007
Yejun Gong
Michigan Technological University
8/7/2007 8/17/2007
Kun Gou
Texas A & M University
8/7/2007 8/17/2007
Jason E. Gower
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Gary B. Green
The Aerospace Corporation
8/7/2007 8/18/2007
Chad Michael
Griep
University of Rhode Island
8/7/2007 8/17/2007
Sergei Grudinin
Forschungszentrum Jülich
7/22/2007 8/3/2007
Venkata Suresh
Reddy
Guthikonda
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Jeffrey Haack
University of Wisconsin
8/7/2007 8/17/2007
Woods Halley
University of Minnesota Twin Cities
7/24/2007 8/3/2007
Nicholas M.
Harrison
Imperial College London
7/29/2007 8/2/2007
Carsten
Hartmann
Free University of Berlin
7/25/2007 8/3/2007
Pieter Hendrickx
University of Ghent (UG)
7/21/2007 8/5/2007
Milena Hering
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Andres Heyden
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Tony Hill
University of Minnesota Twin Cities
7/23/2007 8/3/2007
John R. Hoffman
Lockheed Martin Missiles and Space
Company, Inc.
8/8/2007 8/18/2007
Benjamin J.
Howard
University of Minnesota Twin Cities
9/1/2006 8/21/2007
Jingwei Hu
University of Wisconsin
8/7/2007 8/17/2007
Xueying Hu
University of Michigan
8/7/2007 8/17/2007
Yi Huang
Kent State University
8/7/2007 8/17/2007
Jürg Hutter
Universität Zürich
7/31/2007 8/4/2007
Olexandr Isayev
Jackson State University
7/22/2007 -
8/4/2007
Mark Iwen
University of Michigan
8/7/2007 8/17/2007
Alexander Izzo
Bowling Green State University
7/22/2007 8/4/2007
Rashi Jain
New Jersey Institute of Technology
8/7/2007 8/17/2007
Richard D.
James
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Dan Karls
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Abdelouahab
Kenoufi
Universität Basel
7/28/2007 8/4/2007
Changho Kim
Korea Advanced Institute of Science and
Technology (KAIST)
7/22/2007 8/4/2007
Hyungjun Kim
California Institute of Technology
7/22/2007 8/4/2007
MoonChang Kim
Seoul National University
8/8/2007 8/18/2007
Si-Jo Kim
Andong National University
7/23/2007 8/3/2007
Soojeong Kim
University of Iowa
8/30/2007 1/20/2008
Debra Knisley
East Tennessee State University
8/19/2007 6/1/2008
Leeor Kronik
Weizmann Institute of Science
7/22/2007 8/3/2007
Mandar Kulkarni
University of Alabama at Birmingham
8/7/2007 8/17/2007
Yuen Yick Kwan
Purdue University
8/7/2007 8/17/2007
Song-Hwa Kwon
University of Minnesota Twin Cities
8/30/2005 8/31/2007
David Langreth
Rutgers University
7/31/2007 8/3/2007
Claude Le Bris
École Nationale des Ponts-etChaussées (ENPC)
7/22/2007 8/4/2007
Frédéric
Legoll
École Nationale des Ponts-etChaussées
7/22/2007 8/4/2007
Anton Leykin
University of Minnesota Twin Cities
8/16/2006 8/15/2008
Qizhen Li
University of Nevada
7/22/2007 8/4/2007
Xiantao Li
Pennsylvania State University
7/23/2007 8/3/2007
Hstau Y Liao
University of Minnesota Twin Cities
9/2/2005 8/31/2007
Florence J. Lin
University of Southern California
7/25/2007 8/3/2007
Liping Liu
California Institute of Technology
7/22/2007 8/3/2007
Xinlian Liu
Hood College
7/22/2007 8/3/2007
Yun Liu
University of Minnesota Twin Cities
8/8/2007 8/17/2007
Marie Lopez del
Puerto
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Jianfeng Lu
Princeton University
7/21/2007 8/3/2007
Laura Lurati
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Hannah Markwig
University of Minnesota Twin Cities
9/1/2006 8/31/2007
Glenn Martyna
IBM Corporation
7/22/2007 8/3/2007
Nicola Marzari
Massachusetts Institute of Technology
7/29/2007 8/1/2007
Timur Milgrom
Clemson University
8/7/2007 8/18/2007
Julie C. Mitchell
University of Wisconsin
7/22/2007 8/2/2007
Michal Mlejnek
Corning
7/22/2007 8/3/2007
Darin Mohr
University of Iowa
8/7/2007 8/18/2007
Robert Molt Jr
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Arash A. Mostofi
University of Cambridge
7/30/2007 8/3/2007
Alexey Neelov
Universität Basel
7/22/2007 8/4/2007
Jiawang Nie
University of Minnesota Twin Cities
9/1/2006 8/31/2007
Mechie Nkengla
University of Illinois
8/7/2007 8/17/2007
Christian
Ochsenfeld
Eberhard-Karls-Universität Tübingen
7/30/2007 8/3/2007
Vincent
QuennevilleBelair
McGill University
8/7/2007 8/18/2007
Aravind
Rammohan
Corning
7/22/2007 8/3/2007
Fernando Reitich
University of Minnesota Twin Cities
8/8/2007 8/17/2007
Andres Reyes
Universidad Nacional de Colombia
7/22/2007 8/4/2007
Shantanu Roy
Universität Basel
7/22/2007 8/4/2007
Yousef Saad
University of Minnesota Twin Cities
7/30/2007 8/3/2007
Prasanjit Samal
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Julien Saur
École Nationale des Ponts-etChaussées (ENPC)
7/22/2007 8/4/2007
Andreas Savin
Université de Paris VI (Pierre et Marie
Curie)
7/31/2007 8/3/2007
Abdallah SayyedAhmad
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Arnd Scheel
University of Minnesota Twin Cities
7/15/2004 8/31/2007
Gustavo E.
Scuseria
Rice University
7/29/2007 8/3/2007
Chehrzad
Shakiban
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Josef Aaron
Sifuentes
Rice University
8/7/2007 8/18/2007
Viktor N.
Staroverov
University of Western Ontario
7/31/2007 8/4/2007
Gabriel Stoltz
École Nationale des Ponts-etChaussées (ENPC)
7/22/2007 8/4/2007
Mark A. Stuff
General Dynamics Advanced Information
Systems
8/7/2007 8/18/2007
Stephen Taylor
University of Auckland
7/21/2007 8/6/2007
Helmi Temimi
Virginia Polytechnic Institute and State
University
8/7/2007 8/18/2007
Michael Teter
Cornell University
7/22/2007 8/4/2007
Walter Thiel
Max-Planck-Institut für
Kohlenforschung
7/29/2007 8/3/2007
Carl Toews
University of Minnesota Twin Cities
9/1/2005 8/31/2007
Donald G.
Truhlar
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Igor Tsukerman
University of Akron
7/22/2007 8/3/2007
Mark E.
Tuckerman
New York University
7/22/2007 8/3/2007
Erkan Tüzel
North Dakota State University
7/22/2007 8/3/2007
Paolo Valentini
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Kochuparambil
Deenamma
Vargheese
Corning
7/22/2007 8/3/2007
Sorkin
Viacheslav
University of Minnesota Twin Cities
7/23/2007 8/3/2007
John Voight
University of Minnesota Twin Cities
8/15/2006 8/31/2007
Roman
Voskoboynikov
University of Cambridge
7/22/2007 8/5/2007
Rodolphe
Vuilleumier
Université de Paris VI (Pierre et Marie
Curie)
7/27/2007 8/2/2007
Sinisa Vukovic
University of Toronto
7/22/2007 8/4/2007
Feng Wang
Kent State University
7/22/2007 8/3/2007
Ting Wang
University of Michigan
8/7/2007 8/17/2007
Yan Alexander
Wang
University of British Columbia
8/2/2007 8/3/2007
Yilun Wang
Rice University
8/7/2007 8/17/2007
Renata
Wentzcovitch
University of Minnesota Twin Cities
7/31/2007 8/3/2007
Tomasz A.
Wesolowski
Université de Genève
7/29/2007 8/5/2007
Jahmario
Lemonte
Williams
Mississippi State University
8/7/2007 8/18/2007
Seongho Wu
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Dexuan Xie
University of Wisconsin
7/22/2007 8/4/2007
Zhenqiu Xie
Purdue University
8/7/2007 8/17/2007
Xiangrong Xin
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Jinglong Ye
Mississippi State University
8/7/2007 8/18/2007
Hongchao Zhang
University of Minnesota Twin Cities
9/1/2006 8/31/2008
Lisa Zhang
Lucent Technologies Bell Laboratories
8/7/2007 8/18/2007
Yan Zhaw
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Jingjing Zheng
University of Minnesota Twin Cities
7/23/2007 8/3/2007
Jintong Zheng
University of Delaware
8/7/2007 8/17/2007
Weifeng Zhi
University of Kentucky
8/7/2007 8/18/2007
Yunkai Zhou
Southern Methodist University
7/22/2007 8/4/2007
Johannes
Zimmer
University of Bath
7/22/2007 8/4/2007
Legend: Postdoc or Industrial Postdoc
Long-term Visitor
IMA Affiliates:
3M, Boeing, Carnegie-Mellon University, Corning, ExxonMobil, Ford, General Electric,
General Motors, Georgia Institute of Technology, Honeywell, IBM, Indiana University, Iowa
State University, Johnson & Johnson, Kent State University, Lawrence Livermore National
Laboratory, Lockheed Martin, Los Alamos National Laboratory, Medtronic, Michigan State
University, Michigan Technological University, Microsoft Research, Mississippi State
University, Motorola, Northern Illinois University, Ohio State University, Pennsylvania State
University, Purdue University, Rice University, Rutgers University, Sandia National
Laboratories, Schlumberger-Doll, Schlumberger-Doll Research, Seoul National University,
Siemens, Telcordia, Texas A & M University, University of Chicago, University of Cincinnati,
University of Delaware, University of Houston, University of Illinois at Urbana-Champaign,
University of Iowa, University of Kentucky, University of Maryland, University of Michigan,
University of Minnesota, University of Notre Dame, University of Pittsburgh, University of
Tennessee, University of Texas, University of Wisconsin, University of Wyoming, US Air
Force Research Laboratory, Wayne State University, Worcester Polytechnic Institute