Current Research Interests
My primary research interest is in algorithm design and analysis, and my current
research interests are in graph algorithms, parallel and distributed computing, and fine-grained complexity.
Postscript and Adobe pdf files of some of
my recent papers are available below. Most of my papers are also
available from online copies of journals and conferences.
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Recent Papers
Vijaya Ramachandran, Elaine Shi, ``Data oblivious algorithms for
multicores,''
Proc. ACM SPAA, July 2021, pp. 373-384.
arXiv:2008.00332, August 2020.
[PDF file]
Udit Agarwal, Vijaya Ramachandran, ``Faster Deterministic All Pairs Shortest Paths in Congest Model,'' Proc. ACM SPAA, July 2020, pp. 11-21.
(Best paper nominee.)
Udit Agarwal, Vijaya Ramachandran, ``Distributed weighted all pairs shortest paths through pipelining,''
Proc. IEEE IPDPS, May 2019.
[PDF file]
Udit Agarwal, Vijaya Ramachandran,
``Finding k simple paths and cycles,''
Proc. Intl. Symp. on Algorithms and Computation (ISAAC), December 2016.
[PDF file]
Matteo Pontecorvi, Vijaya Ramachandran,
``Fully dynamic betweenness centrality,''
Proc. Intl. Symp. on Algorithms and Computation (ISAAC), December 2015.
[PDF file]
Meghana Nasre, Matteo Pontecorvi, Vijaya Ramachandran,
``Decremental all-pairs all shortest paths and betweenness centrality,''
Proc. Intl. Symp. on Algorithms and Computation (ISAAC), December 2014.
[PDF file]
Meghana Nasre, Matteo Pontecorvi, Vijaya Ramachandran,
``Betweenness centrality --- Incremental and faster,''
arXiv:1311.2147v3, 2013. Refereed conference version in Proc. Math. Foundations of Comp. Sci. (MFCS), August 2014.
[PDF file]
R.A. Chowdhury, V. Ramachandran, F. Silvestri, B. Blakeley,
``Oblivious algorithms for multicores and network of processors''
Jour. of Parallel and Distributed Processing, Vol 73, pp. 911-925, 2013.
[PDF file]
R. Cole and V. Ramachandran,
``Analysis of randomized work-stealing with false sharing,''
Proc 27th IPDPS, 2013.
[PDF file]
F. Ellen, V. Ramachandran, and P. Woelfel,
``Efficient Fetch-and-Increment,''
Proc. DISC 2012, LNCS 7611, pp. 16-30, 2012.
[PDF file]
R. Cole and V. Ramachandran,
``Efficient resource oblivious algorithms for multicores with false sharing,''
IPDPS 2012.
[PDF file]
A. Katti and V. Ramachandran,
``Competitive cache replacement strategies for shared cache environments,''
IPDPS 2012.
[PDF file]
[A. Katti Masters Thesis]
R. Cole and V. Ramachandran,
``Revisiting the cache miss analysis of multithreaded algorithms,''
LATIN 2012.
[PDF file]
[full manuscript PDF]
R. Cole and V. Ramachandran,
``Resource-oblivious sorting on multicores,''
Proc. International Colloquium of Automata, Languages and Programming
(ICALP), Track A,
Springer LNCS Volume 6198, pp. 226-237, 2010.
[PDF file]
R. A. Chowdhury, V. Ramachandran,
``The cache-oblivious Gaussian elimination paradigm: Theoretical
framework, parallelization and experimental evaluation.''
Theory of Computing Systems, 47(1):878--919, 2010.
Special Issue for SPAA 2007.
[PDF file]
`
G. Blelloch, R. A. Chowdhury, P. Gibbons, V. Ramachandran, S. Chen,
M. Kozuch, ``Provably good multicore cache performance for divide-and-conquer
algorithms,'' Proc. ACM-SIAM Symposium on Discrete Algorithms (SODA),
pp. 501-510, 2008.
[PDF file]
C. Demetrescu, M. Thorup, R. Chowdhury, V. Ramachandran,
``Oracles for distances avoiding a failed node or link",
SIAM Journal on Computing, vol. 37, no. 5, pp. 1299-1318, 2008.
[PDF file]
D. Fernholz, V. Ramachandran,
``The $k$-orientability thresholds for $G_{n,p}$.''
Proc. ACM-SIAM Symposium on Discrete Algorithms (SODA),
pp. 459-468, January 2007.
[PDF file]`
D. Fernholz, V. Ramachandran, ``The diameter of sparse random graphs,''
Random Structures and Algorithms (RSA), vol. 31, no. 4, pp. 482-516,
2007.
[PDF file]
Selected Papers 2006 and Earlier
R. A. Chowdhury, V. Ramachandran,
``Cache-oblivious dynamic programming.''
Proc. ACM-SIAM Symposium on Discrete Algorithms (SODA), January 2006.
[pdf file]
S. Pettie, V. Ramachandran, ``A shortest path algorithm for
real-weighted undirected graphs,'' SIAM Journal on Computing,
34(6):1398--1431, 2005.
[PDF file]
D. Fernholz, V. Ramachandran,
"Cores and connectivity in sparse random graphs".
Technical report TR04-13, 2004.
[Postscript file]
[PDF file]
D. Fernholz, V. Ramachandran,
"The giant $k$-core of a random graph with a specified degree sequence,"
unpublished manuscript, November 2003.
[Postscript file]
[PDF file]
R. A. Chowdhury, V. Ramachandran,
"External-memory exact and approximate all-pairs shortest-paths in
undirected graphs."
Extended abstract in Proc. ACM-SIAM Symp. on Discrete Algorithms (SODA),
January 2005.
[pdf file]
A. Prakash, A. Aziz, V. Ramachandran.
"Randomized Parallel Schedulers for Switch-Memory-Switch Routers:
Analysis and Numerical Studies."
Extended abstract in Proc. INFOCOM, March 2004.
[PDF file]
G. Ganapathy, V. Ramachandran, T. Warnow.
"On Contract-and-Refine Transformations Between Phylogenetic Trees."
Extended abstract in Proc. ACM-SIAM SODA, January 2004.
[Postscript file]
[PDF file]
V. Ramachandran, B.Grayson, M. Dahlin. "Emulations between QSM, BSP and LogP: A framework for general-purpose
parallel algorithm design."
Journal of Parallel and Distributed Computing, vol. 63, 2003, pp. 1175-1192.
[PDF file]
G. Ganapathy, V. Ramachandran, T. Warnow.
"Better Hill-Climbing Searches for Parsimony."
Proc. Workshop on Algorithms for Bioinformatics (WABI),
September 2003, Budapest, Hungary.
X. Zhang, C. Bajaj, V. Ramachandran.
"Isosurfaces:
Parallel and out-of-core view-dependent isocontour visualization using
random data distribution."
Extended abstract in Proc. Data Visualisation 2002, Eurographics/IEEE TCVF
Symposium, Barcelona, Spain 2002, pp. 9-18.
S. Pettie, V. Ramachandran, S. Srinath, ``Experimental evaluation of
a new shortest path algorithm,''
UTCS Technical Report TR-01-37, 2001.
Proc. 4th Workshop on Algorithm
Engineering and Experiments (ALENEX02), January 2002.
[Postscript file]
[PDF file]
S. Pettie, V. Ramachandran, "A Randomized Time-Work Optimal
Parallel Algorithm for Finding a Minimum Spanning Forest."
SIAM Journal on Computing, vol. 31, no. 6, pp. 1879-1895, 2002.
[PDF file]
P. Gibbons, Y. Matias, V. Ramachandran. "Can a
shared memory model serve as a bridging model for parallel computation?"
Theory of Computing Systems Special Issue on papers from SPAA'97, vol. 32,
no. 3, 1999, pp. 327-359.
[PDF file]
B.Grayson, M. Dahlin, V. Ramachandran. "Experimental evaluation of QSM:
A simple shared-memory model."
TR98-21, CS dept., Univ. of Texas at Austin, November 1998. (Summary
in Proc. IPPS/SPDP 1999.)
[Postscript file]
[PDF file]
V. Ramachandran. "A general purpose
shared-memory model for parallel computation."
Algorithms for Parallel Processing, Volume 105, IMA Volumes in
Mathematics and its Applications, Springer-Verlag, 1999, pp. 1-17.
[Postscript file]
[PDF file]
M. Adler, P. Gibbons, Y. Matias, V. Ramachandran.
"Modeling parallel bandwidth: Local vs.
global restrictions."
Algorithmica Special Issue on Coarse Grained Parallel Algorithms,
vol. 24, no. 3-4, 1999, pp. 381-404.
[Postscript file]
[PDF file]
P.B. Gibbons, Y. Matias, V. Ramachandran. "The
queue-read queue-write asynchronous PRAM model."
Theoretical Computer Science, vol. 196, 1998, pp. 3-29.
[Postscript file]
[PDF file]
P.D. MacKenzie, V. Ramachandran.
"ERCW PRAMs and optical communication." Theoretical Computer Science, vol. 196,
1998, pp. 153-180.
[Postscript file]
[PDF file]
P. Gibbons, Y. Matias, V. Ramachandran.
"The QRQW PRAM:
Accounting for contention in parallel algorithms." SIAM Journal
on Computing, vol. 28, no. 2, pp. 733-769, 1999.
[Postscript file]
[PDF file]
C. K. Poon, V. Ramachandran, "A randomized linear work EREW PRAM
algorithm to find a minimum spanning forest."
Algorithmica, vol. 35, no. 3, pp. 257-268, 2003.
(Extended abstract in Proc. 8th Annual
International Symposium on Algorithms and Computation (ISAAC '97),
Springer-Verlag LNCS vol. 1530, December 1997, pp. 212-222.)
[Postscript file]
[PDF file]
M. R. Korupolu, V. Ramachandran, "Quasi-fully dynamic algorithms for two-connectivity, cycle equivalence
and related problems." Algorithmica, to appear.
Extended abstract in Proc. European
Symposium on Algorithms (ESA'97), Springer-Verlag LNCS vol. 1284,
September 1997, pp. 326-340.
[Postscript file]
[PDF file]
V. King, C. K. Poon, V. Ramachandran, S. Sinha, "An optimal EREW PRAM algorithm for minimum spanning tree verification."
Information Processing Letters, vol. 62, no. 3, 1997, pp. 153-159.
[Postscript file]
[PDF file]
P. Gibbons, Y. Matias, V. Ramachandran, "Efficient low-contention parallel algorithms." Journal of Computer
and System Sciences, vol. 53, No. 3, 1996, pp. 395-416. (Special Issue
on papers from ACM SPAA'94).
[Postscript file]
[PDF file]
V. Ramachandran, H. Yang, "An efficient
parallel algorithm for the general planar monotone circuit value
problem." SIAM Journal on Computing. vol. 25, 1996, pp. 312-339.
[Postscript file]
[PDF file]
X. Han, P. Kelsen, V. Ramachandran, R. E. Tarjan,
"Finding minimal spanning subgraphs in
linear time." SIAM Journal on Computing. vol. 24, 1995, pp. 1332-1358.
[Postscript file]
[PDF file]
P. Kelsen, V. Ramachandran, "On finding
minimal two connected subgraph." Journal of Algorithms. vol. 18,
1995, pp. 1-49.
[Postscript file]
[PDF file]
V. Ramachandran, J.H. Reif, "Planarity
testing in parallel." Journal of Computer and Systems Sciences
(Special Issue on papers from FOCS'89). Vol. 49, 1994, pp. 517-561.
[Postscript file]
[PDF file]
V. Ramachandran, H. Yang, "Finding the
closed partition of a planar graph." Algorithmica. vol. 11, 1994,
pp. 443-468.
[Postscript file]
[PDF file]
T.-S. Hsu, V. Ramachandran, "On finding
a minimum augmentation to biconnect a graph." SIAM Journal on
Computing. 1993, pp. 889-912.
[Postscript file]
[PDF file]
V. Ramachandran, "Parallel open ear
decomposition with applications to graph biconnectivity and
triconnectivity." Chapter in `Synthesis of Parallel Algorithms,'
J.H. Reif, ed., Morgan-Kaufmann, 1993, pp. 275-340.
[Postscript file]
[PDF file]
D. Fussell, V. Ramachandran, R. Thurimella, "Finding
triconnected components by local replacement." SIAM Journal on
Computing, 1993, pp. 587-616.
[Postscript file]
[PDF file]
G. L. Miller, V. Ramachandran, "A new
graph triconnectivity algorithm and its parallelization."
Combinatorica. Vol. 12, 1992, pp. 53-76.
[Postscript file]
[PDF file]
S. Buss, S. A. Cook, A. Gupta, V. Ramachandran, ``An optimal
parallel algorithm for formula evaluation.''
SIAM Jour. Computing, Vol 21, 1992, pp. 755-780.
[PDF file]
T.-S. Hsu, V. Ramachandran, "A linear time algorithm for triconnectivity augmentation." Proc. 32nd Annual
IEEE Symposium on Foundations of Computer Science. 1991, pp. 548-559.
[Postscript file]
[PDF file]
P. Gibbons, R. Karp, V. Ramachandran, D. Soroker, R. Tarjan,
"Transitive compaction in parallel via branchings." Journal of Algorithms. Vol. 12, no. 1, 1991,
pp. 110-125.
[Postscript file]
[PDF file]
A. Kanevsky, V. Ramachandran, "Improved algorithms for graph four-connectivity." Jour. Computer and System
Sciences (FOCS'87 Special Issue). Vol. 42, 1991, pp. 288-306.
[Postscript file]
[PDF file]
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