Faculty Research Publications (Electrical Engineering and Computer Science)
http://hdl.handle.net/1957/7303
This collection includes scholarly articles produced by EECS faculty and students.
20150804T01:26:34Z

A technique for error estimation of linewidth and damping parameters extracted from ferromagnetic resonance measurements
http://hdl.handle.net/1957/56531
A technique for error estimation of linewidth and damping parameters extracted from ferromagnetic resonance measurements
Buford, Benjamin; Dhagat, Pallavi; Jander, Albrecht
Ferromagnetic resonance (FMR) characterization, using a vector network analyzer (VNA), is widely used to determine anisotropy, gfactor, and Gilbert damping parameter of magnetic thin films, but results are typically reported without calculation of the measurement accuracy. We present a method of processing VNAFMR measurements to determine both the value and confidence interval of these properties. The discussion is presented using FMR data obtained from stacks of MgO/CoFeB/Ta/CoFeB/MgO with varying CoFeB thickness. Measured Sparameters are deembedded, drift corrected, fit to a Lorentzian curve, and analyzed to produce a confidence interval. A method of plotting the results of the Lorentzian fitting such that fitting errors or measurement drift can be visually analyzed is shown.
Article Copyright 2015 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.; This is the publisher’s final pdf. The published article can be found at: http://scitation.aip.org/content/aip/journal/jap
20150507T00:00:00Z

A PolynomialTime Approximation Scheme for Euclidean Steiner Forest
http://hdl.handle.net/1957/56397
A PolynomialTime Approximation Scheme for Euclidean Steiner Forest
Borradaile, Glencora; Klein, Philip N.; Mathieu, Claire
We give a randomized O(n polylog n)time approximation scheme for the Steiner forest problem in the Euclidean plane. For every fixed ε > 0 and given n terminals in the plane with connection requests between some pairs of terminals, our scheme finds a (1 + ε) approximation to the minimumlength forest that connects every requested pair of terminals.
© ACM, 2015. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Algorithms (TALG), 11(3), Article 19, (January 2015) http://doi.acm.org/10.1145/2629654
20150101T00:00:00Z

Min stCut Oracle for Planar Graphs with NearLinear Preprocessing Time
http://hdl.handle.net/1957/56396
Min stCut Oracle for Planar Graphs with NearLinear Preprocessing Time
Borradaile, Glencora; Sankowski, Piotr; WulffNilsen, Christian
For an undirected nvertex planar graph G with nonnegative edgeweights, we consider the
following type of query: given two vertices s and t in G, what is the weight of a min stcut in G?
We show how to answer such queries in constant time with O(n log⁴ n) preprocessing time and
O(n log n) space. We use a GomoryHu tree to represent all the pairwise min cuts implicitly.
Previously, no subquadratic time algorithm was known for this problem. Since allpairs min cut
and the minimum cycle basis are dual problems in planar graphs, we also obtain an implicit
representation of a minimum cycle basis in O(n log⁴ n) time and O(n log n) space. Additionally,
an explicit representation can be obtained in O(C) time and space where C is the size of the
basis.
These results require that shortest paths are unique. This can be guaranteed either by using
randomization without overhead, or deterministically with an additional log² n factor in the
preprocessing times.
© ACM, 2015. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Algorithms (TALG), 11(3), Article 16, (January 2015)} http://doi.acm.org/10.1145/2684068
20150101T00:00:00Z

Subspace Methods for Data Attack on State Estimation: A Data Driven Approach
http://hdl.handle.net/1957/56274
Subspace Methods for Data Attack on State Estimation: A Data Driven Approach
Kim, Jinsub; Tong, Lang; Thomas, Robert J.
Data attacks on state estimation modify part of system
measurements such that the tempered measurements cause
incorrect system state estimates. Attack techniques proposed
in the literature often require detailed knowledge of system
parameters. Such information is difficult to acquire in practice.
The subspace methods presented in this paper, on the other
hand, learn the system operating subspace from measurements
and launch attacks accordingly. Conditions for the existence of
an unobservable subspace attack are obtained under the full
and partial measurement models. Using the estimated system
subspace, two attack strategies are presented. The first strategy
aims to affect the system state directly by hiding the attack vector
in the system subspace. The second strategy misleads the bad data
detection mechanism so that data not under attack are removed.
Performance of these attacks are evaluated using the IEEE 14
bus network and the IEEE 118bus network.
This is an author's peerreviewed final manuscript, as accepted by the publisher. The published article is copyrighted by IEEEInstitute of Electrical and Electronics Engineers and can be found at: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=78; ©2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
20150301T00:00:00Z