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A multiscale model for charge inversion in electric double layers

S. Y. Mashayak, N. R. Aluru
2018 Journal of Chemical Physics  
Classical continuum theories fail to accurately describe electrostatic correlations and molecular effects of water in EDLs.  ...  In this work, we present an empirical potential based quasi-continuum theory (EQT) to accurately predict the molecular-level properties of aqueous electrolytes.  ...  In the LP approach, a Poisson equation with spatially varying dielectric permittivity is solved to determine the mean electrostatic potential, φ, as d dz ε r (z) dφ dz = − q + ρ + (z) + q − ρ − (z) ε 0  ... 
doi:10.1063/1.5026975 pmid:29884053 fatcat:sgle6sgqf5bwxjzl6qxdrsrcyq

A fast approximation algorithm for solving the complete set packing problem

Tri-Dung Nguyen
2014 European Journal of Operational Research  
We also propose a new formulation for finding tighter lower bounds compared to LP relaxation and develop an efficient method for solving the corresponding large-scale MILP.  ...  subsets, these methods are not extendable to the CSPP since the number of feasible subsets is exponentially large.  ...  In general, the linear approximation is more accurate if ||e − Ax I || is small.  ... 
doi:10.1016/j.ejor.2014.01.024 fatcat:gkbnehxl3bgxjnrcumjhnsmmyu

Scheduling in mapreduce-like systems for fast completion time

Hyunseok Chang, Murali Kodialam, Ramana Rao Kompella, T. V. Lakshman, Myungjin Lee, Sarit Mukherjee
2011 2011 Proceedings IEEE INFOCOM  
Since optimal solutions are hard to compute (NP-hard), we propose approximation algorithms that work within a factor of 3 of the optimal.  ...  Large-scale data processing needs of enterprises today are primarily met with distributed and parallel computing in data centers.  ...  Solving the Linear Program LP OPT SCHED One approach to solve LP is to use the ellipsoid algorithm with a separation oracle.  ... 
doi:10.1109/infcom.2011.5935152 dblp:conf/infocom/ChangKKLLM11 fatcat:m7q7gmiy6rddzl33phiyqcntny

Underconstrained jammed packings of nonspherical hard particles: Ellipses and ellipsoids

Aleksandar Donev, Robert Connelly, Frank H. Stillinger, Salvatore Torquato
2007 Physical Review E  
We also consider packings that are nearly jammed and draw connections to packings of deformable (but stiff) particles.  ...  hard particles.  ...  We thank Paul Chaikin for many inspiring discussions of ellipsoid packings.  ... 
doi:10.1103/physreve.75.051304 pmid:17677051 fatcat:dtghrqdzufcl5mufuhkvaupe5m

An Improved LPN Algorithm [chapter]

Éric Levieil, Pierre-Alain Fouque
2006 Lecture Notes in Computer Science  
Algorithm M is said to (q, t, m, θ)-solve the LP N k,ε problem if P r[s ← {0, 1} k : M As,ε (1 k ) = s] ≥ θ and furthermore M runs in time at most t, memory at most m, and makes at most q queries to its  ...  All protocols in the HB family rely on the computational hardness of the LPN problem. The LPN Problem.  ...  We would like to thank Louis Granboulan for various discussions and suggestions about this work.  ... 
doi:10.1007/11832072_24 fatcat:qakgyrzlnffnrorcjtgyjuqdbe

Solving and analyzing side-chain positioning problems using linear and integer programming

C. L. Kingsford, B. Chazelle, M. Singh
2004 Bioinformatics  
We relax the integrality constraint to give a polynomial-time linear programming (LP) heuristic.  ...  It is NP-complete to find even a reasonable approximate solution to this problem. We seek to put this hardness result into practical context.  ...  ACKNOWLEDGEMENTS The authors would like to thank Amy Keating, Jessica Fong, Gevorg Grigoryan, Elena Nabieva, Robert Osada, Elena Zaslavsky and the reviewers for insightful comments on this manuscript.  ... 
doi:10.1093/bioinformatics/bti144 pmid:15546935 fatcat:pxcqktvh2vfuxmjsxlb3jycuuq

Distributed Optimal Gas-Power Flow Using Convex Optimization and ADMM [article]

Cheng Wang, Wei Wei, Jianhui Wang, Linquan Bai, Yile Liang
2016 arXiv   pre-print
In the proposed distributed algorithm, OGF and OPF are solved independently, and coordinated by the alternating direction multiplier method (ADMM).  ...  This paper proposes a convex optimization based distributed algorithm to solve multi-period optimal gas-power flow (OGPF) in coupled energy distribution systems.  ...  Particularly, in the MILP approximation method, we use an eight-segment piecewise linear approximation to replace the nonlinear Weymouth equation and an eight-segment linear approximation to represent  ... 
arXiv:1610.04681v1 fatcat:u4hk2pjndjanbox5fcwndniimm

Mean-field theory of random close packings of axisymmetric particles

Adrian Baule, Romain Mari, Lin Bo, Louis Portal, Hernán A. Makse
2013 Nature Communications  
Here, we present a mean-field formalism to estimate the packing density of axisymmetric non-spherical particles.  ...  Moreover, we find a packing density of 73.6% for lens-shaped particles, representing the densest random packing of the axisymmetric objects studied so far.  ...  We are grateful to C.F. Schreck and C.S. O'Hern for discussions and for providing simulated data on 3D packings of dimers. We are also grateful to F. Potiguar for discussions, T.  ... 
doi:10.1038/ncomms3194 pmid:23877324 fatcat:5vekkpupijgeney5y5qjl55sg4


Yanheng Zhang, Chris Chu
2009 Proceedings of the 2009 International Conference on Computer-Aided Design - ICCAD '09  
Instead of solving the computationally expensive LP, we discover that the LP formulation could be relaxed and solved by a very efficient longest-path computation.  ...  Shifting in each direction can be formulated as a linear program (LP) for resizing each G-Cell.  ...  Since Equations 1,3,8 and 9 are all difference constraints, we propose the following strategy to solve the LP. We use an outer loop which keeps decreasing σ until the LP is feasible.  ... 
doi:10.1145/1687399.1687465 dblp:conf/iccad/ZhangC09 fatcat:6wryyns7hzh47iy77qdtba64bq

The rheological behavior of concentrated colloidal dispersions

John F. Brady
1993 Journal of Chemical Physics  
For a suspension of Brownian hard spheres there are two contributions to the macroscopic stress: a hydrodynamic and a Brownian stress.  ...  Both the scaling law and the predicted magnitude are in excellent accord with experiment.  ...  We have also assumed that there are no external torques acting on the particles, which would give rise to an antisymmetric contribution to the bulk stress of the form --nE' (LP), (9) where (L') is the  ... 
doi:10.1063/1.465782 fatcat:cht5y7dmb5hvhfikv7zdwwh66m

A Fast Algorithm for Separated Sparsity via Perturbed Lagrangians [article]

Aleksander Mądry, Slobodan Mitrović, Ludwig Schmidt
2017 arXiv   pre-print
Sparsity-based methods are widely used in machine learning, statistics, and signal processing.  ...  Although the sparsity constraint is non-convex, our perturbed Lagrangian approach is still guaranteed to find a globally optimal solution.  ...  Corollary 1 Let y, X, θ * , and e be as in the sparse linear model in Equation (2) . We assume that supp(θ * ) ∈ M k,∆ and that X satisfies the model-RIP for M k,∆ .  ... 
arXiv:1712.08130v1 fatcat:gq2klxmtujd5dpq35j4uz7i3ie

Undecidability and hardness in Mixed-Integer Nonlinear Programming

Leo Liberti
2018 Reserche operationelle  
algorithmically, and, for the subclasses which can, whether they are hard to solve.  ...  We start by reviewing the problem of representing a solution, which is linked to the correct abstract computational model to consider.  ...  Apparently, the unwritten standards of scientific writing, which I know and abide by, but thought could be a matter of personal choice in an invited survey, are in fact vigorously enforced (trust me).  ... 
doi:10.1051/ro/2018036 fatcat:hofoinsdazgkrgf7cjogqojuba

Stochastic packing-market planning

Daniel Golovin
2007 Proceedings of the 8th ACM conference on Electronic commerce - EC '07  
This matches up to constants the best approximation ratio known for Maximum k-Set Packing.  ...  We also give a linear programming based approximation for EP (G). These techniques may be of independent interest.  ...  Acknowledgments Thanks to Vahab Mirrokni for providing the initial question that served as the impetus for this work, and thanks to Guy Blelloch, Ryan O'Donnell, Alan Frieze, Matt Streeter, and David Brumley  ... 
doi:10.1145/1250910.1250936 dblp:conf/sigecom/Golovin07 fatcat:sxjoy56abzhknpjej6vvxuxiri

Aggregate overhaul and supply chain planning for rotables

Joachim Arts, Simme Douwe Flapper
2013 Annals of Operations Research  
We prove that this planning problem is strongly N P-hard, but we also provide computational evidence that the mixed integer programming formulation can be solved within reasonable time for real-life instances  ...  Furthermore, we show that the linear programming relaxation can be used to aid decision making. We apply the model in a case study and provide computational results for randomly generated instances.  ...  Acknowledgements The authors would like to thank Bob Huisman of NedTrain for introducing this research topic to the authors and many stimulating discussions.  ... 
doi:10.1007/s10479-013-1426-0 fatcat:7ahmeygj4reghhwvh3ucrqlmk4

Heterogeneous UGV-MAV exploration using integer programming

Ayush Dewan, Aravindh Mahendran, Nikhil Soni, K. Madhava Krishna
2013 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems  
The formulation is also studied for distributed system, where agents are divided into multiple teams using graph partitioning.  ...  We have also presented comparison with previous methods based on distance traversed and computational time to signify advantages of presented method.  ...  Comparing F LP problem with problem posed in 1, we find they are similar. Both are challenging (NP Hard) linear integer programming problems.  ... 
doi:10.1109/iros.2013.6697188 dblp:conf/iros/DewanMSK13 fatcat:7ntovwj2l5dupfuowitqsjky4u
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