# Faculty News Briefs

### September 2015

On September 4, 2015 Senior Lecturer Adena Calden facilitated two discussion panels for new graduate students at UMass Amherst on "Leading Effective Discussions."

Panos Kevrekidis had a very busy summer of 2015. He was the principal organizer, together with Lora Billings of Montclair State University, of the SIAM biennial meeting on Applications of Dynamical Systems. The meeting hosted approximately 900 participants and took place in Snowbird, Utah. Right after that meeting, Panos hosted another meeting, together with Avadh Saxena of Los Alamos and Fred Cooper of the Santa Fe Institute, at the historic La Fonda hotel in Santa Fe and at the Santa Fe Institute for about 50 participants on "Emergent Paradigms of Nonlinear Complexity" in early June. Finally, the third conference organized by Panos during 2015 took place in early September at Princeton University on "Waves, Spectral Theory and Applications." The latter was a 50-participant workshop that Panos co-organized with Roy Goodman of NJIT, Eduard Kirr of UIUC, and Jeremy Marzuola of UNC under the auspices of the National Science Foundation and in honor of the 60th birthday of Michael Weinstein of Columbia University. During this interval of time, Panos also delivered invited lectures at a minisymposium during the Snowbird meeting, in Halifax CA, in a workshop on pattern formation organized at Dalhousie University by Theo Kolokolnikov, and at the Center for Nonlinear Studies of the Los Alamos National Laboratory.

Professor Rob Kusner was a keynote speaker at the "Shape Up" conference on mathematics and materials in Berlin during the week of September 14-18, 2015. He spoke on "The Willmore, Canham and Helfrich Problems."

On September 18, 2015 Professor Michael Lavine gave a talk in the Department of Statistics at Duke University titled "Approximately Exact Calculations for Linear Mixed Models." On September 25 he gave a talk in the Department of Statistics at North Carolina State University titled "On Likelihood." During the period August 3 - September 4 he attended a workshop on Forensic Statistics. His paper titled "Approximately Exact Calculations for Linear Mixed Models" and cowritten with Bray and Hodges was accepted for publication by *Electronic Journal of Statistics*.

Professor Ivan Mirkovic received a Simons Fellowship, which allowed him to extend his sabbatical semester to the full academic year 2014-2015. He gave invited talks at conferences at MSRI (December 2014), in Paris (January 2015), in Marseille (March 2015), in Dubrovnik, Croatia (June 2015), and in Banff, Canada (August 2015). He also attended a workshop in Banff on Conformal Field Theory in 6 dimensions. During the fall semester of 2014 he was a Simons Professor and Eisenbud Professor in the Mathematical Sciences Research Institute in Berkeley, CA. He visited the University of Chicago for a month and gave a series of four talks in the Drinfeld seminar. He also visited Université Blaise Pascal in Clermont-Ferrand, France for a month.

On September 12, 2015 Professor Jenia Tevelev gave a talk titled "The Craighero-Gattazzo Surface Is Simply-Connected" at the AGNUBC (BC-Northeastern Algebraic Geometry Conference) at Northeastern University in Boston, MA.

### August 2015

Covering June, July, and August 2015

Professor Emeritus John Buonaccorsi presented a one-day short course on “Measurement Error" at the Joint 24th International Chinese Statistical Association Applied Statistics Symposium and 13th Graybill Conference, held June 14–17, 2015 in Fort Collins, Colorado. The Graybill Conference was held in honor of Franklin Graybill, founder of the Department of Statistics at Colorado State University. John was also a co-author, along with colleagues from the Medical School at the University of Oslo, of a paper titled “Sensitivity of Regression Calibration to Non-Perfect Validation Data with Application to the Norwegian Women and Cancer Study.” The paper was published in *Statistics in Medicine*.

Professor Matthew Dobson presented a poster titled “Algorithms for the Long-Time Simulation of Steady Nonequilibrium Flow” at the 7th International Workshop on Nonequilibrium Thermodynamics in Hilvarenbeek, The Netherlands.

In August 2015 a paper by Professor Richard S. Ellis and Professor Shlomo Ta'asan of Carnegie Mellon University was accepted for publication by *International Journal of Stochastic Analysis*. The paper is titled “Large Deviation Analysis of a Droplet Model Having a Poisson Equilibrium Distribution.” On July 2 Richard participated in two 30-minute interviews with Father Jurgen Liias as part of the program “Wellsprings of Faith” on Melrose (MA) Cable TV. During the first interview Richard discussed his spiritual journey, and during the second interview he discussed the Hebrew language, the Torah, and his experiences teaching the Torah. The interviews were broadcast on Melrose Cable TV twelve times during August and September and were conducted in conjunction with Richard's appointment as an adjunct professor in the Department of Judaic and Near Eastern Studies at UMass Amherst.

Professor Patrick Flaherty gave a talk at the Joint Statistical Meetings in Seattle, WA titled “GLAD: A Mixed-membership Model for Heterogeneous Tumor Subtype Classification.” He gave a talk with the same title at the International Chinese Statistical Association Meeting in Fort Collins, CO.

Professor Markos Katsoulakis and Professor Matthew Dobson, along with students, postdocs, and a team of researchers from Brown University, University of Delaware, University of North Carolina-Chapel Hill, and University of California San Diego, recently received a $3.1 million award from U.S. Defense Advanced Research Projects Agency (DARPA). This grant focuses on developing a predictive modeling framework for the reliable computational design of novel, superior, and/or lower cost materials for applications to catalysis, energy production, and energy storage. Additional background on this research project is available at http://www.supercomputingonline.com.

This summer Professor Rob Kusner participated in the 65th birthday celebration conferences at Imperial College and Warwick University for his advisor Rick Schoen. While at Imperial on July 16, Rob lectured on “The Canham Problem” about the shape of bending-energy minimizing surfaces in space with volume and area constraints. Rob is on sabbatical this year and has just begun a semester-long Seminar on Minimal surfaces at the University of Pennsylvania this fall. Next spring at MSRI in Berkeley he will serve as a research professor during their special differential geometry semester.

Professor Michael Lavine attended the Joint Statistics Meetings August 9–12, 2015, a SAMSI workshop on Challenges in Computational Neuroscience August 17–21, and a SAMSI workshop on Forensic Statistics August 31 – September 4.

Professor Franz Pedit was a speaker at the Differential Geometry Workshop on Harmonic Maps, Biharmonic Maps, Harmonic Morphisms, and related topics held during the period June 10–12, 2015 in Cagliari, Italy. The title of his talk was “Integrable Surface Geometry for non-Abelian Topology.” He gave a talk with the same title as a combined plenary speaker for the George Boole Mathematical Sciences Conference and the Irish Mathematical Society meeting held during the period August 17–28 in Cork, Ireland.

Professor Jenia Tevelev participated in the II Latin American School of Algebraic Geometry and Applications (II ELGA) – Thematic Program on Algebraic Geometry, held at Hotel La Plage, Cabo Frio, Rio de Janeiro during the period June 1–12, 2015. There he gave a talk titled “The Craighero-Gattazzo Surface is Simply-Connected,” which was based on a paper written with a former UMass Amherst graduate student, Julie Rana, now a postdoc at the University of Minnesota, and with a former UMass VAP, Giancarlo Urzua, now a professor at Pontificia Universidad Catolica de Chile. In addition, Jenia’s paper titled “$\bar M_{0,n}$ Is Not a Mori Dream Space” was published in *Duke Mathematical Journal*, volume 164, no. 8 (2015), pp. 1641–1667. This paper was written with a former UMass VAP, Ana-Maria Castravet, now a professor at Northeastern University.

Professor Hongkun Zhang co-organized a Workshop on Stochastic Methods for Non-Equilibrium Dynamical Systems, held at AIM, San Jose, during the period June 1–5, 2015. She was also a plenary speaker at the The Rocky Mountain Dynamical Systems Conference, held in Provo, UT during the period June 8–11. There she gave a talk titled “Diffusive Random Billiards.” In addition, Hongkun co-organized an AIM SQuaREs program on Random Billiards together with her collaborator Renato Feres and his students, which was held during the period July 20–24, in San Jose. This three-year program provides full financial support for a small research group to work together at AIM for a week each year. Finally, Hongkun Zhang was a plenary speaker at the conference on Stochastic Dynamical Systems and Applications, held at the Chinese Academy of Science in Beijing during the period August 4–10. There she gave a one-hour talk titled “Statistical Properties of Chaotic Billiards.”

### May 2015

Professor Tom Braden attended a workshop on Enveloping Algebras and Geometric Representation Theory at the Mathematisches Forschungsinstitut Oberwolfach, and a conference on Representation Theory and Geometry of Symplectic Resolutions at Northeastern University. He gave a talk titled “Ringel Duality for Perverse Sheaves on Hypertoric Varieties” at both meetings.

Postdoctoral Research Associate Efstathios Charalampidis gave a talk at the SIAM Conference on Applications of Dynamical Systems held in Snowbird, Utah. The talk was titled “Vector Rogue Waves and Dark-Bright Boomeronic Solitons in Autonomous and Non-Autonomous Settings.”

Professor Matthew Dobson presented a poster on “Cell List Algorithms for Nonequilibrium Molecular Dynamics” at The Tony and Pat Houghton Conference on Non-Equilibrium Statistical Mechanics. The conference was held at ICERM at Brown University during the period May 4–5, 2015.

Donald Geman, a faculty member in our department from 1970 to 2001, was elected to the National Academy of Sciences (NAS) in April 2015 “in recognition of [his] distinguished and continuing achievements in original research.” Don is currently in the Department of Applied Mathematics and Statistics at Johns Hopkins University. In 1984 Don and his brother Stuart, who is at Brown University, published one of the landmark papers in statistics, “Stochastic Relaxation, Gibbs Distributions, and the Bayesian Restoration of Images” (*IEEE Transactions on Pattern Analysis and Machine Intelligence*, 6). Additional background on Don’s work and his election to NAS is given at http://www.bme.jhu.edu/news-events/news-highlights.php?id=504.

Professor Markos Katsoulakis was a keynote speaker at the International Symposium for Big Data and Predictive Computational Modeling, which was held at the Technical University of Munich during the period May 18–20, 2015. The symposium included plenary talks from 12 researchers in the areas of Uncertainty Quantification and Computational Statistics/Machine Learning. The emphasis of the meeting was on identifying synergies and common themes for these communities and innovative research directions that can accelerate the impact of uncertainty modeling and computing in engineering and the sciences. Details on the symposium are given at http://www.tum-ias.de/bigdata2015/focus-impact.html.

At the Lehigh University Geometry and Topology Conference on May 23, 2015, Professor Rob Kusner gave a lecture titled “Critical Configurations of Hard Disks on the 2-Sphere.” The following Wednesday, May 27, Rob served on a PhD panel at Drexel University for Jingmin Chen. Rob and Jingmin’s Drexel advisor Thomas Yu have been advising and collaborating with Jingmin on the Willmore, Canham and Helfrich Problems, which characterize the shapes of equilibrium vesicles under various constraints. Rob describes the event as being like a “homecoming” since exactly a century earlier his father’s father earned a graduate degree in Electrical Engineering at Drexel University at the peak of the vacuum-tube era.

On May 14, 2015 Professor Michael Lavine delivered a seminar, “Approximately Exact Calculations for Linear Mixed Models,” in the Department of Biostatistics at the Harvard Chan School of Public Health.

Postdoctoral Research Associate Ioannis Pantazis won a $50,000 award from the Defense Advanced Research Projects Agency (DARPA) as the bronze medal recipient in a predictive modeling contest. The contest focuses on the debilitating, mosquito-borne disease known as the chikungunya virus. The goal is to accurately forecast how the disease might spread in the Americas and the Caribbean. DARPA wants to find technologies that U.S. health officials can use to make decisions in the case of an outbreak. The announcement of the award points out that the participants, which include Ioannis, “identified gaps in current forecasting capabilities and created a set of tools that can immediately help improve forecasting and guide response decisions for the current chikungunya outbreak.” Details are given at http://www.darpa.mil/news-events/2015-05-27.

During the period May 18–20, 2015 Professor Hongkun Zhang co-organized the Dynamical Systems, Ergodic Theory and Probability Conference Dedicated to the Memory of Nikolai Chernov. The conference was held at the University of Alabama at Birmingham. At the conference she gave a talk titled “Optimal Bounds for Decay Rates of Colorations of Nonuniformly Hyperbolic Systems.”

### April 2015

Postdoctoral Research Associate Efstathios Charalampidis was invited to give a talk at the 9th IMACS International Conference on Nonlinear Evolution Equations and Wave Phenomena: Computation and Theory, which was held at the University of Georgia in Athens, GA. The talk was titled “Dark-bright Solitons in Coupled Nonlinear Schrödinger (NLS) Equations with Unequal Dispersion Coefficients.”

At the UMass Amherst Undergraduate Commencement Ceremony on May 8, 2015, Nicholas Chunias, a graduating senior in our department, was named a Jack Welch Scholar. This honor was given to him and to three other graduating seniors in recognition for their leadership and executive ability. Nicholas was a dual degree recipient in finance and mathematics.

On April 25, 2015 Professor Erin Conlon gave an invited talk at the New England Statistics Symposium in Storrs, CT. The talk was titled “Computational Tools for Bayesian Methods in Big Data and Data Science.” Erin also organized and chaired an invited session at the same conference, which also took place on April 25. The session was titled “Statistical Challenges in Modeling and Applications.” This session also included two faculty members from our department, Anna Liu and Daeyoung Kim.

Professor Panos Kevrekidis has had a very busy winter and spring term. In January 2015, he visited the University of Milan and gave a talk on his work on localized excitations in a one-day workshop there on Localized Dynamics in Nonlinear Hamiltonian Lattices. Then in February, Panos was invited to the Institute for Mathematical Sciences of the National University of Singapore for their workshop on High Performance and Parallel Computing Methods and Algorithms for Material Defects. Panos gave a talk at the workshop on his recent advances in the dynamics of vortices and vortex rings. In March, Panos gave a short talk on Bose-Einstein condensates at the APS March Meeting. At the same meeting he was honored as an American Physical Society Fellow from the Topical Group in Statistical and Nonlinear Physics. He then visited the University of Pittsburgh, where he gave both a colloquium on his work on granular media and an Applied Math seminar on his work on Bose-Einstein condensates. During the same month he also visited UMass Boston as well as Boston University, where he also delivered lectures on his recent work on quantum and classical systems, respectively. At the beginning of April, Panos delivered one of the three plenary lectures at the 9th IMACS International Conference on Nonlinear Evolution Equations and Wave Phenomena: Computation and Theory. Finally, he also recently visited the University of Colorado, Boulder, where he delivered a chalk talk on localized structures in discrete systems as well as a colloquium on Nonlinear Waves in Bose-Einstein condensates.

### March 2015

On March 24, 2015 Professor Matthew Dobson gave an invited talk titled “Derivation and Simulation of Nonequilibrium Langevin Dynamics” at Penn State at the SIAM Sponsored Workshop on Dimension Reduction: Mathematical Methods and Applications. On March 15 he presented a poster titled “Cell List Algorithms for Nonequilibrium Molecular Dynamics” at the SIAM Conference on Computational Science and Engineering.

During March 2015 Visiting Assistant Professor Ravi Kalpathy gave two talks. He gave a contributed talk on March 14 at the Probability Theory and Combinatorial Optimization conference at Duke University. On March 18 he gave a talk at the Seminar in Functional Analysis and Related Areas at the Catholic University of America. Both talks were titled “Degree Profile of m-ary Search Rrees: A Vehicle for Data Structure Compression.” Ravi had one refereed publication accepted in March 2015. His data science paper titled “Degree Profile of m-ary Search Trees: A Vehicle for Data Structure Compression” and co-authored with Hosam Mahmoud is scheduled to appear in *Probability in the Engineering and Informational Sciences*.

During the week of March 16-20, 2015 Professor Rob Kusner helped lead a workshop on "Small Clusters, Polymer Vesicles and Unusual Minima" at Brown University's ICERM.

Professor Michael Lavine was recently appointed to lead one of three teams drafting the American Statistical Association’s forthcoming position paper on P-values.

On March 10, 2015 Professor Franz Pedit gave a talk at the conference “Geometry of Smooth and Discrete Surfaces” at Technical University Berlin. His talk was titled “Integrable Surface Geometry for non-Abelian Topology.”

Professor Hongkun Zhang has been awarded a 2015 Simons Fellowship for her project titled “Stochastic Perspectives of Billiard Dynamics.” The awardees for 2015 are announced on the Simon’s Foundation web site. The Simons Foundation, established by noted mathematician and investor James H. Simons, awards fellowships annually to leading researchers in mathematics, theoretical physics, neuroscience, and other fields. The foundation awards a maximum of 40 fellowships in mathematics annually to faculty in the U.S., Canada, and the United Kingdom. The Fellows Program under the Simons Foundation Division for Mathematics and the Physical Sciences provides funds to faculty for up to a semester-long research leave from classroom teaching and administrative obligations. Simons Fellows are chosen based on research accomplishment in the five years prior to application and the potential scientific impact of the fellowship.

## Department of Mathematics and Statistics