Dylan T. Walker

44 Hawthorne Ave. (203) 763-9014

Hamden, CT 06517 dtw203@nyu.edu

**Education**:

  -------------- --------------------------------------------------------
  2002-2008      Ph.D., *Stony Brook University* in theoretical physics
                 of complex systems

  1997-2002      Bachelors of Science in Physics from *New York
                 University* (Magna Cum Laude)

  1997-2002      Bachelors of Engineering in Electrical Engineering from
                 *Stevens Institute of Technology* (Summa Cum Laude)
  -------------- --------------------------------------------------------

**Research Experience**:

Information networks, citation networks, collaborative networks
(recommendation systems), social networks, biomolecular networks,
internet (AS-level), WWW

*Time-critical Information Networks* -- With the rise of social
collaboration and web 2.0 concepts, many information systems have come
into popular use that involve collaborative ranking. In particular, news
aggregation systems such as digg.com or reddit.com rely on users to vote
articles to their proper rank order. These information systems are
time-critical in the sense that a news item must be promoted to
sufficient rank quickly in order to make the headline before it is "old
news". The information networks that represent these systems have two
types of nodes: users and articles. These networks evolve throughout
time as new articles are introduced and possibly become more connected.
Ranking of such time-critical information networks is a challenging
field of research. The bipartite nature of the network suggests the
simultaneous ranking of articles and users. Multi-agent modeling of
network evolution can uncover rich information about how different types
of users interact and point to ranking algorithms that encompass user
reputation and avoid sources of bias.

*Protein Interaction Networks* -- Protein Interaction networks represent
reversible protein binding interactions. In typical biological systems,
(e.g., in the living cell) protein binding is dominated by dimer
interactions (the binding of two single monomer proteins into a dimer).
Proteins exist in large multiplicity within the cell in total
concentrations dictated by the cellular machinery that regulates protein
production. At any instant, proteins may be free or bound to other
proteins. The equilibrium state in a well-mixed system is dictated by
the law of mass action (LMA) equations. Fluctuations in free and bound
concentration (large and small) about equilibrium occur and, due to the
large number of interactions and the structure of the interaction
network, can be nontrivial. Two types of interesting noise are present
in these systems: spontaneous thermal noise and driven fluctuations. We
calculate the network's collective effect on both types of fluctuations.

*Citation Networks* -- Citation networks are formed by a set of
documents that cite one another. A typical example is the network of
scientific journal publications, where a publication is a node and a
citation is a directed edge pointing from the citing publication to the
cited publication. Due to their large size, it is untenable to navigate
most citation networks without the aid of a content search and ranking
scheme. Ranking schemes based on network topology are particularly
useful in ranking large networks, a notable example being that of
Google's PageRank for the web. Diffusion-based algorithms, like
PageRank, are mathematically equivalent to diffusion processes where a
large number of random walkers navigate the network by following links
from one node to the next. Unlike in the case of the web, random walkers
on citation networks always flow in the direction of older publications
because citations are always made to papers that have been published in
the past. This feature of citation networks, referred to as aging,
biases naïve diffusion-based ranking algorithms towards the oldest
papers. Our CiteRank algorithm corrects for aging effects and favors
recent publications pertinent to modern research.

**Publications & Presentations**:

+-----------+----------------------------------------------------------+
| To Be     | *Ranking of Time-Critical Information Networks*          |
| Submitted |                                                          |
+-----------+----------------------------------------------------------+
| To Be     | *Noise in Mass Action Equilibrium of Protein Binding     |
| Submitted | Networks*                                                |
+-----------+----------------------------------------------------------+
| 2007      | *Perturbations in Protein Interaction Networks*          |
|           |                                                          |
|           | Boulder School for Condensed Matter and Materials        |
|           | Physics -- Poster                                        |
+-----------+----------------------------------------------------------+
| 2006      | *Ranking Scientific Publications Using a Model of        |
|           | Network Traffic*                                         |
|           |                                                          |
|           | D. Walker, H. Xie, K.K. Yan, S. Maslov, *J. Stat. Mech.* |
|           | 6 10 (2007)                                              |
+-----------+----------------------------------------------------------+
| 2006      | *Designed & programmed CiteRank website:                 |
|           | [http://www.citerank.org](http://www.citerank.org/)*     |
+-----------+----------------------------------------------------------+
| 2006      | *Ageing in Citation Networks*                            |
|           |                                                          |
|           | International Conference on Network Science (Netsci '06) |
|           | -- Talk                                                  |
+-----------+----------------------------------------------------------+
|           |                                                          |
+-----------+----------------------------------------------------------+
| 2003      | *CERN Workshop on Bump Bonding and Die Attach            |
|           | Technologies Summary*                                    |
|           |                                                          |
|           | D. Walker, J. Heuser                                     |
+-----------+----------------------------------------------------------+

**Teaching Experience**:

  ------------ ----------------------------------------------------------
  2004 -- 2005 Honors Classical Physics, *Stony Brook University*

  2003 -- 2004 Classical Physics, *Stony Brook University*

  2002 -- 2003 Private student tutoring in the following subjects:
               pre-calculus, single- and multi-variable calculus, linear
               algebra, differential equations, all physics courses
  ------------ ----------------------------------------------------------

**Honors and Awards**:

  ------------- ----------------------------------------------------------
  2006          *Boulder Condensed Matter Summer School*

  2006          *International Conference on Network Science* (NetSci '06)

  2003          *CERN Bump Bonding and Die Attach Technologies*

  2003          *PHENIX / NA60 Silicon Pixel Detector Liaison @ CERN*

  2002          Morse Medal for academic excellence, *New York University*

  2001          Inducted into *Eta Kappa Nu Engineering Honors Society*

                

  2000          Inducted into *Sigma Pi Sigma Physics Honors Society*

  **Skills**:   
  ------------- ----------------------------------------------------------

*Mathematics*: Stochastic Systems, Nonlinear Dynamical Processes, Data
Mining, Machine Learning

*Programming*: C/C++, Python, Matlab, PHP, SQL

*Web Design*: Adobe Suite, CSS, JavaScript