A Fast Algorithm for Simulated Annealing
|
|
- Suzanna Lambert
- 7 years ago
- Views:
Transcription
1 Physica Scripta. Vol. T38, 40-44, A Fast Algorithm for Simulated Annealing Hong Guo, Martin Zuckermann, R. Harris and Martin Grant Centre for the Physics of Materials, Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, Canada H3A 2T8 Received September 24, 1990; accepted October 26, 1990 Abstract We present a new deterministic algorithm for simulated annealing and demonstrate its applicability with several classical examples: the ground state energies of the 2d and 3d short range king spin glasses, the traveling salesman problem, and pattern recognition in computer vision. Our algorithm is based on a microcanonical Monte Carlo method and is shown to be a powerful tool for the analysis of a variety of problems involving combinatorial optimization. We show that the deterministic method generates optimal solutions faster and often better than the standard Metropolis method. 1. Introduction Over the last two decades extensive analytical and numerical work has been performed in order to obtain approximate solutions to optimization problems involving many parameters and conflicting constraints [ 11. Classic examples of such problems include the traveling salesman problem (TSP), the three dimensional spin glass ground state, and the wiring of gates in chip design. There exists an entire class of these problems which is termed NP-complete (non-deterministic polynomial time complete) because the computational effort used to find an exact solution increases exponentially as the total number of degrees of freedom, N, of the problem. This implies that approximation methods are required for further analysis. Indeed, heuristic methods are widely used for such practical optimization problems in computer science and engineering and they prove to be extremely fruitful. However, these methods are usually problem-oriented and their domain of application is restricted to the particular problem which they are designed to solve. As the value of N for a particular problem increases, algorithms based on statistical method become useful, and allow unified treatment of the NP-complete problems. The most successful statistical method to date is the stochastic model of simulated annealing introduced by Kirkpatrick, Gelatt, and Vecchi in 1983 [2]. In simulated annealing, a cost function is constructed to characterize the optimization process and minimization of this function gives an approximation to the optimal solution of the problem. A controlled thermal treatment followed by slow cooling give the system the chance to jump out of local minima of the cost function to improve solutions. Constructing the cost function can in principle be problematic, although in practice the choice is often straightforward. For instance, the distance the salesman travels is the cost function of TSP. Simulated annealing has been applied to the problem of finding the ground state of a spin glass (SG) which is an NP-complete problem in three dimensions [3, 41. A short range Ising spin glass is described by the Hamiltonian where Si = f 1 is the spin at site i of a cubic lattice; Jij is usually assumed to be a random number drawn from a Gaussian distribution (Gaussian model), or takes values of f J with equal probability ( f J model). The sum is over all the nearest neighbor pairs. The spin glass system is highly frustrated and has a large number of metastable states with similar energies. Its ground state also has high degeneracy. At low temperatures it can be trapped in one of the metastable states. Thermal noise then induces uphill steps in energy space which in principle eventually brings the system to equilibrium. The simulated annealing method starts with the system at high temperature and lowers the temperature in small steps according to a prescribed annealing schedule. For a SG, the system energy is used as the cost function. At each temperature, enough simulation steps (spin flip trials) must be performed in order to ensure the system is equilibrated [3, 41. At very low temperature, this process causes the SG system to freeze into a state which is at least an approximation to the true ground state. For other combinational optimization problems, a temperature is also introduced as a control parameter measured in units of the cost function. Usually simulated annealing is performed using the Metropolis [5] algorithm with temperature T fixed at each state of the annealing schedule. The total cost function of the system is lowered due to local ordering and the temperature provides the activation necessary to bring the system out of its metastable states. However, for metastable states with high energy barriers, it is very hard for the thermal noise to provide enough activation. Thus the system can be locked into a local minimum of the cost function space. This is the reason that the annealing schedule must be carefully designed and the annealing steps must be small [3, 41. In this paper we present a study of an algorithm for simulated annealing which directly and deterministically minimizes the cost function. The method is based on a microcanonical ensemble in which the system of interest is in contact with an auxiliary system (a demon ) and the cost function (energy) is exchanged between both systems. In this method the temperature is actually a derived quantity. This allows large local temperature fluctuations which are essential for bringing the system out of metastable states. The methodology of the microcanonical Monte Carlo was first proposed by Creutz [6] to study the Ising model and has subsequently been applied to a variety of physical systems [7]. Although equilibrium statistical mechanics using the canonical and microcanonical ensembles are equivalent, the dynamics of the algorithms based on these ensembles are different. We find that this microcanonical Monte Carlo method is very naturally applicable to optimization problems because it is deterministic and allows large temperature fluctuations. To our knowledge, an early attempt to use microcanonical Monte Carlo to study low temperature properties of a spinglass was due to Dasgupta, Ma and Hu [8]. Recently, Sourlas
2 A Fast Algorithm for Simulated Annealing 41 [9] has also applied a microcanonical method to investigate the ergodicity properties of a spin-glass. While the ideas are similar, the algorithm to be presented below is most close to the one proposed by Clover [lo]. In Section 2 we present the method and apply it to several classic problems: the Ising spin glass, the STP and a short discussion on its application to computer vision. Section 3 is reserved for a short summary and conclusion. All of our simulations were performed on a SUN 3/50 workstation. 2. Method and results Although the microcanonical Monte Carlo method has been discussed in detail by Creutz [6], we briefly present it here for completenes. Consider a nearest neighbor Ising model described by Hamiltonian (1) with J,j = J, Elsing = - J 1 SiS. (2) To study its equilibrium properties, a microcanonical ensemble is constructed by letting a demon with energy Ed interact with the spins such that the total energy E = Elsing + Ed is conserved. In a Monte Carlo simulation, the energy required to flip a spin, 6E, is compared with Ed, and if Ed 2 GE, the flip is permitted and an amount of 6E is subtracted from Ed. Otherwise the trial is abandoned. It is easy to show [6] that the average demon energy measures the temperature of the Ising system in equilibrium. The microcanonical Monte Carlo method is generalized for simulated annealing as follows. We begin the simulation with the system at a disordered high temperature state and allow it to interact with the demon. At each stage of the annealing schedule a maximum value of the demon cost function, CY (e.g., Ed for SG), is specified such that if the demon cost function cd > Cy, cd is reset to Cr. This procedure brings the system very efficiently to lower and lower cost function states. For frustrated systems with local ordering, a hot demon can melt a local ordered region and bring the system out of metastable state. In the simulations reported below, we found that the choice of CyX was rather robust: any reasonable choice did equally well. This method can also be used after a heuristic treatment of the problem. In that case, since the initial state is almost ordered, we start with the demon possessing a large value of the cost function and then anneal down Ground state energy of the Zsing spin glass The short range Ising spin glass described by (1) has been extensively studied for many years [l 13. For the f J model, transfer matrix calculations [ 121 yield the ground state energies: Eo/J x f 0.01 for d = 2, and Eo/J x f 0.02 for d = 3, where d is the dimensionality of the system. For the Gaussian model, the transfer matrix method [12] gives Eo/6J x f 0.01 for d = 2 and Eo/SJ x f0.03 for d = 3, where GJis the width of the Gaussian distribution for Jij. Other numerical methods have also been used to obtain the ground state energies but usually yield values higher than those quoted above, illustrating the difficulty of reaching the true ground state. For example, simulated annealing using Metropolis Monte Carlo gives, for the 2d Gaussian spin glass [4], Eo/SJ x Grest et al. then extrapolate to the limit of infinitely slow cooling rate [4] to get a value of We have applied our method to study both spin glass models. In 2d, the systems were on square lattices with up to 100 spins. In 3d, cubic lattices with up to 303 spins were used. Periodic boundary conditions were used for all simulations. The units of energy were taken as J for the f J model and 6J for the Gaussian model. For the 2d Gaussian model, we started with Er = 8 and annealed down to E r = 0 with equal steps of 1. The systems used consisted of 100 spins, and 400 or 800 Monte Carlo trials per spin were done for each Er. 10 runs were averaged to give the value Eo/GJ x f 0.004, which is in good agreement with that given by the transfer matrix method. Our results also compare favorably with those of the Metropolis algorithm. For the 3d Gaussian model, the range of we used was from 8 down to 0 with steps of 1 for the first 5 stages and 0.5 for the last 5 stages. For lattices with 163 spins, 600 Monte Carlo trials per spin were done for each of the r. Averaging 30 independent runs gave Eo/SJ x f which is somewhat higher than the transfer matrix estimate, although within the error bars, but considerably lower than that found using the Metropolis Monte Carlo [3]. For lattices with 303 spins, test runs were also done using the same annealing schedule but with only 300 Monte Carlo trials per spin per Er, we foundf Eo/6J = after averaging 5 runs. Since the transfer matrix calculation quoted above is performed on systems with 43 spins, and there is very little information about the ground state energy for larger systems, our results could provide a benchmark for further simulations. The 2d & J model was studied by using from 16 down to 0 in steps of 4, with either 800 or 1600 Monte Carlo steps per spin for each of the Er on lattices with 50 spins. Averaging 10 independent configurations gave Eo/J x & 0.004, again in excellent agreement with the transfer matrix calculation. Test runs on systems with 100 spins essentially gave the same result. The Metropolis algorithm gives Eo/J x while the extrapolation gives [4]. Our results agree very well with these values. The 3d f J model simulation used the range of Er from 20 down to 0 in steps of 4. A total of 12 Y S were used for a run, 600 or 1200 Monte Carlo steps were done for each ETX. For lattices of 163 spins, 40 independent runs were averaged to find the value of the ground state energy, E,:J z f (we have also performed test runs on lattices with 303 spins; 5 independent runs averaged to give ). Note that this value is actually lower than that of the transfer matrix calculation, though within its error bars. Grest et al. [4] give a value of using Metropolis Monte Carlo, which they extrapolate to Figure 1 shows the decrease of energy as a function of time for the 2d models using the parameters mentioned above. The energy decreases continuously until Er is lowered and a sudden drop of energy occurs. This is more apparent for the f J model because the energy is discrete. Figure 2 compares approaches to the ground state as a function of time using both Creutz and Metropolis Monte Carlo methods for the 2d Gaussian model. The same bond configuration (J, ) is used for the two simulations. Grest et al. [4] have shown that the ground state energies obtained by Metropolis Monte Carlo method depend on the cooling rate, thus we used the same parameters which gave the best results in their simulation. AS shown in Fig. 2, our method gives a faster convergence to the
3 42 Hong Guo et al. h I+, I Gaussian model... model *-* " ' ' I ' ' ' I ' ' ' ' ' SO time Fig. 1. Typical runs showing the approach to the ground state of the 2d models. Energy is measured in SJ for the Gaussian model and J for the f J model. The time is measured in Monte Carlo steps. System sizes are 10O2 for the Gaussian model and 5d for the & J model. ground state, in addition to the better values obtained. Our results also show little variation of the energy, since in microcanonical Monte Carlo the total energy is a conserved quantity and Ed has an upper bound. In all of our simulations we found that the choice of erax is rather robust. Provided we start with some large value and goes down with reasonable steps, the final results are not significantly affected. Of course, careful design of the annealing schedule could in principle improve the rate of convergence to the ground state. The numbers quoted above are for typical runs with a natural annealing schedule. Another advantage or our algorithm is that no extrapolation [4] is needed to get the values for true ground state for the 2d models. For the 3dmodels, lower energy states are also found using our method The traveling salesman problem The TSP has been studied for a long time as the representative problem for combinatorial optimizations [ 131. The TSP tries to find the shortest path connecting N nodes (cities), with the path ending at its starting node. Since this belongs to the class of NP-complete problems, exact solutions have been attempted only for cases with less than a few hundred nodes. However, simulated annealing has been applied to this problem where up to several thousand nodes are present [2]. We have applied our algorithm to TSP. We first consider a system with N = 400 nodes randomly distributed on a square of linear size fi = 20. The cost function, L, is the length of the path connecting the N nodes. The length is measured in the "Manhattan" metric where the distance between two nodes is the sum of their separations along the Cartesian coordinates. We number the nodes from 1 to N and a path is represented as a particular permutation of { 1... N}. The rearrangements of the path are done using the strategy of Lin [14] where moves consist of reversal and replacement [ 151. We used an annealing schedule in which the maximum of the demon cost function L y starts at fi/4 and is then usually lowered in equal steps. At most 45 Ly's are used in a simulation. A Monte Carlo step here corresponds to a reconfiguration trial on the path, and we used up to (400N) Monte Carlo steps for each annealing stage. However, if there are too many succussful reconfigurations, it either means L y is too large or the system is too "hot", and thus we can go to the next annealing stage with a lower value of Ly. In our simulation, if 4000 (10N) successful reconfigurations are made, we jump to the next annealing stage directly. A typical measure of the TSP solution, denoted by a, is the total path length divided by N. a will be independent of N if many runs are averaged [16]. For N = 400, and the nodes uniformly distributed, our algorithm gives a sz 0.98 f 0.03 by averaging 10 independent runs. We obtain the same value of a using the standard simulated annealing with Metropolis Monte Carlo, but more than twice the CPU time was needed. When using (100N) Monte Carlo steps per annealing stage, there is a slight increase in the value of a [17]. Figure 3 shows a typical solution where 400 nodes are distributed in 9 equal size regions separated by empty space. After 15 stages of annealing, long paths acrossing the regions are infrequent while in each region the paths are still rather disordered (see Fig. 3(a)). Fig. 3b is the result after 45 stages of annealing which gives a = Reference [2] gives a larger value a = for the case where the nodes are arranged similarly to ours, although it should be noted that the difference in the a's are presumably due to the details of the actual configurations time Fig. 2. Typical runs using the Creutz and Metropolis Monte Carlo methods for the 2d Gaussian model. Energy is measured in SJ. The same bond configurations are used for the two curves. System size is 10O2. For the Metropolis method, the initial temperature is 1.5 and it is lowered in steps of 0. I. For each temperature, 500 Monte Carlo steps per spin are performed Restoration of corrupted binary images In addition to the two examples discussed above, there are many other practical problems which can be studied with this algorithm. For example, a large class of computer vision and image interpretation problems can be described and discussed within the framework of optimization theory [18, 191. Forest [20] considered the following cost function for the
4 A Fast Algorithm for Simulated Annealing 43 is largest at corners), the annealing method has to be supplemented by other heuristics which preserve the corners [ 191. We are currently studying this problem and results will be presented elsewhere. 3. Conclusion t The main goal of this work has been to introduce a Creutz algorithm for simulated annealing. We found that this method is particularly powerful for problems involving frustration and local ordering. This was demonstrated in the short range Ising spin glass simulations. An obvious merit of the Creutz algorithm is that it is deterministic, so that programs can be made rather efficient. Although an exhaustive investigation of the parameter space was not carried out, we found that other reasonable annealing schedules give essentially the same performance as those presented in the text. This method can therefore provide an efficient approach to optimization problems where no good heuristic method is known. For problems where long range reconfigurations are needed, the performance enhancement of Creutz algorithm over Metropolis algorithm decreases. As mentioned above, we gain only a factor of less than 3 in CPU time for TSP. Improvement in this regard could be achieved by introducing multiple demons into the algorithm, so that at any instant during a simulation, many different demon energies are present to be consulted. A hybrid algorithm of combining the Creutz and Metropolis algorithm could also be useful in some instances. We have also tested another annealing method in which the total cost function, system plus demon, is held constant at each stage of the schedule. The annealing is achieved by systematically lowing the total cost function. Preliminary results show that this method performs as well as the one presented in the text. In conclusion, we have introduced a new algorithm for the simulated annealing of NP-complete problems, and shown that it provides a distinct improvement over previous methods. Fig. 3. (a) A TSP path after 15 stages of annealing starting with LFu = 5 for 400 nodes distributed uniformly in 9 equal size regions: (b) The path after 45 stages of annealing. a = 0.72 for this path. binary image restoration problem E = -.IC $4-1/2 1 Di(l + Si) In (p- - 1) (3) where Si = f 1 denotes the binary values of the pixel i, 0, = f 1 are the initial binary values of the same pixel (i.e. D, is the pixel in the corrupted image); and p is the noise strength with a value between 0 and 1. The sum is over the nearest neighbor pairs of pixels. When an image is corrupted by white noise, it can be shown [20], that the configuration {S,) which minimizes E is an approximation to the original uncorrupted image. The cost function (3) has the same form as a random field Ising model where Di is a space dependent random field. Thus we have applied our method of simulated annealing to determine the global minimum of (3) and fine that the noise is annealed away very efficiently. For an image (a Chinese character) of pixels corrupted with noise strengthp = 0.25 (25% of the pixels are corrupted), only 3% noise is left after 120 trials per pixel (6 annealing stages with 20 trials each). However, since corners of a picture are not preserved by thermal treatment (the probability of flipping Acknowledgements This work was supported by the Natural Sciences and Engineering Research Council of Canada, and le Fonds pour la Formation de Chercheurs et I Aide a la Recherche de la Province du Quebec. References I IO. Schwefel, H. P., Numerical Optimization of Computer Models, John Wiley and Sons (1981)(Edited by N. Christofides, A. Mingoui, P. Toth and C. Sandi), Combinatorial Optimization London and New York, Wiley-interscience (1979). Kirkpatrick, S., Gelatt, C. D. and Vecchi, M. P., Science 220, 671 (1983); Kirkpatrick, S., J. Stat. Phys. 34, 975 (1984). Soukoulis, C. M., Levin, K. and Grest, G. S., Phys. Rev. B28, 1495 (1983); Reger, J. D., Binder, K. and Kinzel, W., Phys. Rev. B30,4028 ( 1985). Grest, G. S., Soukoulis, C. M. and Levin, K., Phys. Rev. Lett. 56, 1148 (1986). Metropolis, N., Rosenbluth, A., Rosenbluth, M., Teller, A. and Teller, E., J. Chem. Phys. 21, 1087 (1953). Creutz, M., Phys. Rev. Lett. 50, 1411 (1983). Bhanot, G., Creutz, M. and Neuberger, H., Nucl. Phys. B235, 417 (1984); Creutz, M., Gocksch, A., Ogilvie, M. and Okawa, M., Phys. Rev. Lett. 53, 875 (1984); Harris, R., Phys. Lett. 111A, 299 (1985). Dasgupta, C., Ma, S. K. and Hu, C. K., Phys. Rev. B20, 3837 (1979). Sourlas, N., Europhys. Lett. 6,. 561 (1988). Clover, M., (unpublished).
5 44 Hong Guo et al. 11. Binder, K. and Young, A. P., Rev. Mod. Phys. 58, 801 (1986) and references therein. 12. Cheung, H. and McMillan, W. L., J. Phys. (London) C16,7027 (1983); Morgenstern, I. and Binder, K., Phys. Rev. Lett. 43, 1615 (1979); Z. Phys. B39, 227 (1980); Phys. Rev. B22, 288 (1980); J. Appl. Phys. 52, 1692 (1981). 13. Dantzig, G. B., Fulkerson, D. R. and Hohnson, S. M., Oper. Res. 2, 393 (1954); Garey, M. R. and Johnson, D. S., Compters and Intractability: A Guide to the theory of NP-Completeness, (Freeman, San Francisco, 1979). 14. Lin, S., Bell Syst. Tech. Jour. 44, 2245 (1965). 15. A FORTRAN program for the traveling salesman problem is provided in the book of William H. Press, Brian P. Flannery, Saul A. Teukolsky and William T. Vetterling, Numerical Recipes. Cambridge University Press, New York (1987). 16. Beardwook, J., Halton, J. H. and Hammersley, J. M., Proc. Cambridge Philos. Soc. 55, 299 (1959). 17. Our value of LY is slightly higher than those of Ref. [2] where the simulated annealing is performed after treatment by a heuristic method. 18. Buxton, B. F. and Murray, D. W., Image and Vision Computing 3, 163 (1985); Buxton, B. F., Buxton, H. and Kashko, A. in Parallel Architectures and Computer Vision (Edited by Ian Page), Clarendon Press, Oxford (1988). 19. Geman, S. and Geman, D., IEEE Trans. PAM1 5, 721 (1984). 20. Forrest, B. M. in Parallel Architectures and Computer Vision (Edited by Ian Page), Clarendon Press, Oxford (1988).
Annealing Techniques for Data Integration
Reservoir Modeling with GSLIB Annealing Techniques for Data Integration Discuss the Problem of Permeability Prediction Present Annealing Cosimulation More Details on Simulated Annealing Examples SASIM
More informationSmall window overlaps are effective probes of replica symmetry breaking in three-dimensional spin glasses
J. Phys. A: Math. Gen. 31 (1998) L481 L487. Printed in the UK PII: S0305-4470(98)93259-0 LETTER TO THE EDITOR Small window overlaps are effective probes of replica symmetry breaking in three-dimensional
More informationMeasuring Line Edge Roughness: Fluctuations in Uncertainty
Tutor6.doc: Version 5/6/08 T h e L i t h o g r a p h y E x p e r t (August 008) Measuring Line Edge Roughness: Fluctuations in Uncertainty Line edge roughness () is the deviation of a feature edge (as
More informationAccurate and robust image superresolution by neural processing of local image representations
Accurate and robust image superresolution by neural processing of local image representations Carlos Miravet 1,2 and Francisco B. Rodríguez 1 1 Grupo de Neurocomputación Biológica (GNB), Escuela Politécnica
More informationResearch on a Heuristic GA-Based Decision Support System for Rice in Heilongjiang Province
Research on a Heuristic GA-Based Decision Support System for Rice in Heilongjiang Province Ran Cao 1,1, Yushu Yang 1, Wei Guo 1, 1 Engineering college of Northeast Agricultural University, Haerbin, China
More informationBerkeley CS191x: Quantum Mechanics and Quantum Computation Optional Class Project
Berkeley CS191x: Quantum Mechanics and Quantum Computation Optional Class Project This document describes the optional class project for the Fall 2013 offering of CS191x. The project will not be graded.
More informationComplexity Theory. IE 661: Scheduling Theory Fall 2003 Satyaki Ghosh Dastidar
Complexity Theory IE 661: Scheduling Theory Fall 2003 Satyaki Ghosh Dastidar Outline Goals Computation of Problems Concepts and Definitions Complexity Classes and Problems Polynomial Time Reductions Examples
More informationA Performance Comparison of Five Algorithms for Graph Isomorphism
A Performance Comparison of Five Algorithms for Graph Isomorphism P. Foggia, C.Sansone, M. Vento Dipartimento di Informatica e Sistemistica Via Claudio, 21 - I 80125 - Napoli, Italy {foggiapa, carlosan,
More informationThe Method of Least Squares
The Method of Least Squares Steven J. Miller Mathematics Department Brown University Providence, RI 0292 Abstract The Method of Least Squares is a procedure to determine the best fit line to data; the
More informationThe Network Structure of Hard Combinatorial Landscapes
The Network Structure of Hard Combinatorial Landscapes Marco Tomassini 1, Sebastien Verel 2, Gabriela Ochoa 3 1 University of Lausanne, Lausanne, Switzerland 2 University of Nice Sophia-Antipolis, France
More informationParallel Simulated Annealing Algorithm for Graph Coloring Problem
Parallel Simulated Annealing Algorithm for Graph Coloring Problem Szymon Łukasik 1, Zbigniew Kokosiński 2, and Grzegorz Świętoń 2 1 Systems Research Institute, Polish Academy of Sciences, ul. Newelska
More informationPerformance Optimization of I-4 I 4 Gasoline Engine with Variable Valve Timing Using WAVE/iSIGHT
Performance Optimization of I-4 I 4 Gasoline Engine with Variable Valve Timing Using WAVE/iSIGHT Sean Li, DaimlerChrysler (sl60@dcx dcx.com) Charles Yuan, Engineous Software, Inc (yuan@engineous.com) Background!
More informationOutline. NP-completeness. When is a problem easy? When is a problem hard? Today. Euler Circuits
Outline NP-completeness Examples of Easy vs. Hard problems Euler circuit vs. Hamiltonian circuit Shortest Path vs. Longest Path 2-pairs sum vs. general Subset Sum Reducing one problem to another Clique
More informationHigh Performance Computing for Operation Research
High Performance Computing for Operation Research IEF - Paris Sud University claude.tadonki@u-psud.fr INRIA-Alchemy seminar, Thursday March 17 Research topics Fundamental Aspects of Algorithms and Complexity
More informationParallel Data Selection Based on Neurodynamic Optimization in the Era of Big Data
Parallel Data Selection Based on Neurodynamic Optimization in the Era of Big Data Jun Wang Department of Mechanical and Automation Engineering The Chinese University of Hong Kong Shatin, New Territories,
More informationDistributed Dynamic Load Balancing for Iterative-Stencil Applications
Distributed Dynamic Load Balancing for Iterative-Stencil Applications G. Dethier 1, P. Marchot 2 and P.A. de Marneffe 1 1 EECS Department, University of Liege, Belgium 2 Chemical Engineering Department,
More informationA Binary Model on the Basis of Imperialist Competitive Algorithm in Order to Solve the Problem of Knapsack 1-0
212 International Conference on System Engineering and Modeling (ICSEM 212) IPCSIT vol. 34 (212) (212) IACSIT Press, Singapore A Binary Model on the Basis of Imperialist Competitive Algorithm in Order
More informationBinary Image Reconstruction
A network flow algorithm for reconstructing binary images from discrete X-rays Kees Joost Batenburg Leiden University and CWI, The Netherlands kbatenbu@math.leidenuniv.nl Abstract We present a new algorithm
More informationComputing with Finite and Infinite Networks
Computing with Finite and Infinite Networks Ole Winther Theoretical Physics, Lund University Sölvegatan 14 A, S-223 62 Lund, Sweden winther@nimis.thep.lu.se Abstract Using statistical mechanics results,
More informationQuantum Monte Carlo and the negative sign problem
Quantum Monte Carlo and the negative sign problem or how to earn one million dollar Matthias Troyer, ETH Zürich Uwe-Jens Wiese, Universität Bern Complexity of many particle problems Classical 1 particle:
More informationIMPROVING PERFORMANCE OF RANDOMIZED SIGNATURE SORT USING HASHING AND BITWISE OPERATORS
Volume 2, No. 3, March 2011 Journal of Global Research in Computer Science RESEARCH PAPER Available Online at www.jgrcs.info IMPROVING PERFORMANCE OF RANDOMIZED SIGNATURE SORT USING HASHING AND BITWISE
More informationSymbolic Determinants: Calculating the Degree
Symbolic Determinants: Calculating the Degree Technical Report by Brent M. Dingle Texas A&M University Original: May 4 Updated: July 5 Abstract: There are many methods for calculating the determinant of
More informationOn the Empirical Evaluation of Las Vegas Algorithms Position Paper
On the Empirical Evaluation of Las Vegas Algorithms Position Paper Holger Hoos ½ Computer Science Department University of British Columbia Email: hoos@cs.ubc.ca Thomas Stützle IRIDIA Université Libre
More informationPARALLELIZED SUDOKU SOLVING ALGORITHM USING OpenMP
PARALLELIZED SUDOKU SOLVING ALGORITHM USING OpenMP Sruthi Sankar CSE 633: Parallel Algorithms Spring 2014 Professor: Dr. Russ Miller Sudoku: the puzzle A standard Sudoku puzzles contains 81 grids :9 rows
More informationOn the k-path cover problem for cacti
On the k-path cover problem for cacti Zemin Jin and Xueliang Li Center for Combinatorics and LPMC Nankai University Tianjin 300071, P.R. China zeminjin@eyou.com, x.li@eyou.com Abstract In this paper we
More informationThe Effects of Start Prices on the Performance of the Certainty Equivalent Pricing Policy
BMI Paper The Effects of Start Prices on the Performance of the Certainty Equivalent Pricing Policy Faculty of Sciences VU University Amsterdam De Boelelaan 1081 1081 HV Amsterdam Netherlands Author: R.D.R.
More informationThe QOOL Algorithm for fast Online Optimization of Multiple Degree of Freedom Robot Locomotion
The QOOL Algorithm for fast Online Optimization of Multiple Degree of Freedom Robot Locomotion Daniel Marbach January 31th, 2005 Swiss Federal Institute of Technology at Lausanne Daniel.Marbach@epfl.ch
More informationSolution of a Large-Scale Traveling-Salesman Problem
Chapter 1 Solution of a Large-Scale Traveling-Salesman Problem George B. Dantzig, Delbert R. Fulkerson, and Selmer M. Johnson Introduction by Vašek Chvátal and William Cook The birth of the cutting-plane
More informationTutorial on Markov Chain Monte Carlo
Tutorial on Markov Chain Monte Carlo Kenneth M. Hanson Los Alamos National Laboratory Presented at the 29 th International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Technology,
More informationBMOA: Binary Magnetic Optimization Algorithm
International Journal of Machine Learning and Computing Vol. 2 No. 3 June 22 BMOA: Binary Magnetic Optimization Algorithm SeyedAli Mirjalili and Siti Zaiton Mohd Hashim Abstract Recently the behavior of
More informationCharacter Image Patterns as Big Data
22 International Conference on Frontiers in Handwriting Recognition Character Image Patterns as Big Data Seiichi Uchida, Ryosuke Ishida, Akira Yoshida, Wenjie Cai, Yaokai Feng Kyushu University, Fukuoka,
More informationSupport Vector Machines with Clustering for Training with Very Large Datasets
Support Vector Machines with Clustering for Training with Very Large Datasets Theodoros Evgeniou Technology Management INSEAD Bd de Constance, Fontainebleau 77300, France theodoros.evgeniou@insead.fr Massimiliano
More informationFast Sequential Summation Algorithms Using Augmented Data Structures
Fast Sequential Summation Algorithms Using Augmented Data Structures Vadim Stadnik vadim.stadnik@gmail.com Abstract This paper provides an introduction to the design of augmented data structures that offer
More informationSolution of Linear Systems
Chapter 3 Solution of Linear Systems In this chapter we study algorithms for possibly the most commonly occurring problem in scientific computing, the solution of linear systems of equations. We start
More informationNP-Completeness and Cook s Theorem
NP-Completeness and Cook s Theorem Lecture notes for COM3412 Logic and Computation 15th January 2002 1 NP decision problems The decision problem D L for a formal language L Σ is the computational task:
More informationOn the Relationship between Classes P and NP
Journal of Computer Science 8 (7): 1036-1040, 2012 ISSN 1549-3636 2012 Science Publications On the Relationship between Classes P and NP Anatoly D. Plotnikov Department of Computer Systems and Networks,
More informationIntroduction to the Monte Carlo method
Some history Simple applications Radiation transport modelling Flux and Dose calculations Variance reduction Easy Monte Carlo Pioneers of the Monte Carlo Simulation Method: Stanisław Ulam (1909 1984) Stanislaw
More informationStatistical Physics, Mixtures of Distributions, and the EM Algorithm
Communicated by Radford Neal Statistical Physics, Mixtures of Distributions, and the EM Algorithm Alan L. Yuille Division of Applied Sciences, Harvard University, Cambridge, M A 02138 USA Paul Stolorz
More informationThe Multi-Item Capacitated Lot-Sizing Problem With Safety Stocks In Closed-Loop Supply Chain
International Journal of Mining Metallurgy & Mechanical Engineering (IJMMME) Volume 1 Issue 5 (2013) ISSN 2320-4052; EISSN 2320-4060 The Multi-Item Capacated Lot-Sizing Problem Wh Safety Stocks In Closed-Loop
More informationEvaluation of Complexity of Some Programming Languages on the Travelling Salesman Problem
International Journal of Applied Science and Technology Vol. 3 No. 8; December 2013 Evaluation of Complexity of Some Programming Languages on the Travelling Salesman Problem D. R. Aremu O. A. Gbadamosi
More informationAn Introduction to Neural Networks
An Introduction to Vincent Cheung Kevin Cannons Signal & Data Compression Laboratory Electrical & Computer Engineering University of Manitoba Winnipeg, Manitoba, Canada Advisor: Dr. W. Kinsner May 27,
More informationEffects of node buffer and capacity on network traffic
Chin. Phys. B Vol. 21, No. 9 (212) 9892 Effects of node buffer and capacity on network traffic Ling Xiang( 凌 翔 ) a), Hu Mao-Bin( 胡 茂 彬 ) b), and Ding Jian-Xun( 丁 建 勋 ) a) a) School of Transportation Engineering,
More informationMulti-layer Structure of Data Center Based on Steiner Triple System
Journal of Computational Information Systems 9: 11 (2013) 4371 4378 Available at http://www.jofcis.com Multi-layer Structure of Data Center Based on Steiner Triple System Jianfei ZHANG 1, Zhiyi FANG 1,
More informationOffline 1-Minesweeper is NP-complete
Offline 1-Minesweeper is NP-complete James D. Fix Brandon McPhail May 24 Abstract We use Minesweeper to illustrate NP-completeness proofs, arguments that establish the hardness of solving certain problems.
More informationIN current film media, the increase in areal density has
IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 1, JANUARY 2008 193 A New Read Channel Model for Patterned Media Storage Seyhan Karakulak, Paul H. Siegel, Fellow, IEEE, Jack K. Wolf, Life Fellow, IEEE, and
More informationA Note on Maximum Independent Sets in Rectangle Intersection Graphs
A Note on Maximum Independent Sets in Rectangle Intersection Graphs Timothy M. Chan School of Computer Science University of Waterloo Waterloo, Ontario N2L 3G1, Canada tmchan@uwaterloo.ca September 12,
More informationMAPPING OF ARBITRARY TRAFFIC DEMAND AND NETWORK TOPOLOGY ON A MESH OF RINGS NETWORK
MAPPING OF ARBITRARY TRAFFIC DEMAND AND NETWORK TOPOLOGY ON A MESH OF RINGS NETWORK Christian Mauz Communication Technology Laboratory ETH Zurich Switzerland mauz@nari.ee.ethz.ch Abstract An efficient
More informationPricing and calibration in local volatility models via fast quantization
Pricing and calibration in local volatility models via fast quantization Parma, 29 th January 2015. Joint work with Giorgia Callegaro and Martino Grasselli Quantization: a brief history Birth: back to
More informationA Non-Linear Schema Theorem for Genetic Algorithms
A Non-Linear Schema Theorem for Genetic Algorithms William A Greene Computer Science Department University of New Orleans New Orleans, LA 70148 bill@csunoedu 504-280-6755 Abstract We generalize Holland
More informationOffline sorting buffers on Line
Offline sorting buffers on Line Rohit Khandekar 1 and Vinayaka Pandit 2 1 University of Waterloo, ON, Canada. email: rkhandekar@gmail.com 2 IBM India Research Lab, New Delhi. email: pvinayak@in.ibm.com
More informationSTA 4273H: Statistical Machine Learning
STA 4273H: Statistical Machine Learning Russ Salakhutdinov Department of Statistics! rsalakhu@utstat.toronto.edu! http://www.cs.toronto.edu/~rsalakhu/ Lecture 6 Three Approaches to Classification Construct
More informationApproximated Distributed Minimum Vertex Cover Algorithms for Bounded Degree Graphs
Approximated Distributed Minimum Vertex Cover Algorithms for Bounded Degree Graphs Yong Zhang 1.2, Francis Y.L. Chin 2, and Hing-Fung Ting 2 1 College of Mathematics and Computer Science, Hebei University,
More informationPHYSICAL REVIEW LETTERS
PHYSICAL REVIEW LETTERS VOLUME 86 28 MAY 21 NUMBER 22 Mathematical Analysis of Coupled Parallel Simulations Michael R. Shirts and Vijay S. Pande Department of Chemistry, Stanford University, Stanford,
More informationA greedy algorithm for the DNA sequencing by hybridization with positive and negative errors and information about repetitions
BULLETIN OF THE POLISH ACADEMY OF SCIENCES TECHNICAL SCIENCES, Vol. 59, No. 1, 2011 DOI: 10.2478/v10175-011-0015-0 Varia A greedy algorithm for the DNA sequencing by hybridization with positive and negative
More informationSIMS 255 Foundations of Software Design. Complexity and NP-completeness
SIMS 255 Foundations of Software Design Complexity and NP-completeness Matt Welsh November 29, 2001 mdw@cs.berkeley.edu 1 Outline Complexity of algorithms Space and time complexity ``Big O'' notation Complexity
More informationSIMPLIFIED PERFORMANCE MODEL FOR HYBRID WIND DIESEL SYSTEMS. J. F. MANWELL, J. G. McGOWAN and U. ABDULWAHID
SIMPLIFIED PERFORMANCE MODEL FOR HYBRID WIND DIESEL SYSTEMS J. F. MANWELL, J. G. McGOWAN and U. ABDULWAHID Renewable Energy Laboratory Department of Mechanical and Industrial Engineering University of
More informationHYBRID GENETIC ALGORITHMS FOR SCHEDULING ADVERTISEMENTS ON A WEB PAGE
HYBRID GENETIC ALGORITHMS FOR SCHEDULING ADVERTISEMENTS ON A WEB PAGE Subodha Kumar University of Washington subodha@u.washington.edu Varghese S. Jacob University of Texas at Dallas vjacob@utdallas.edu
More informationLinear Threshold Units
Linear Threshold Units w x hx (... w n x n w We assume that each feature x j and each weight w j is a real number (we will relax this later) We will study three different algorithms for learning linear
More informationCHAPTER 1 INTRODUCTION
CHAPTER 1 INTRODUCTION Power systems form the largest man made complex system. It basically consists of generating sources, transmission network and distribution centers. Secure and economic operation
More informationSolving Geometric Problems with the Rotating Calipers *
Solving Geometric Problems with the Rotating Calipers * Godfried Toussaint School of Computer Science McGill University Montreal, Quebec, Canada ABSTRACT Shamos [1] recently showed that the diameter of
More informationDecentralized Method for Traffic Monitoring
Decentralized Method for Traffic Monitoring Guillaume Sartoretti 1,2, Jean-Luc Falcone 1, Bastien Chopard 1, and Martin Gander 2 1 Computer Science Department 2 Department of Mathematics, University of
More informationFast Generation of Optimal Music Playlists using Local Search
Fast Generation of Optimal Music Playlists using Local Search Steffen Pauws, Wim Verhaegh, Mark Vossen Philips Research Europe High Tech Campus 34 5656 AE Eindhoven The Netherlands steffen.pauws/wim.verhaegh@philips.com
More informationSupporting Online Material for
www.sciencemag.org/cgi/content/full/313/5786/504/dc1 Supporting Online Material for Reducing the Dimensionality of Data with Neural Networks G. E. Hinton* and R. R. Salakhutdinov *To whom correspondence
More informationNonlinear Model Predictive Control of Hammerstein and Wiener Models Using Genetic Algorithms
Nonlinear Model Predictive Control of Hammerstein and Wiener Models Using Genetic Algorithms Al-Duwaish H. and Naeem, Wasif Electrical Engineering Department/King Fahd University of Petroleum and Minerals
More informationComputer Algorithms. NP-Complete Problems. CISC 4080 Yanjun Li
Computer Algorithms NP-Complete Problems NP-completeness The quest for efficient algorithms is about finding clever ways to bypass the process of exhaustive search, using clues from the input in order
More informationThe Problem of Scheduling Technicians and Interventions in a Telecommunications Company
The Problem of Scheduling Technicians and Interventions in a Telecommunications Company Sérgio Garcia Panzo Dongala November 2008 Abstract In 2007 the challenge organized by the French Society of Operational
More informationFactoring by Quantum Computers
Factoring by Quantum Computers Ragesh Jaiswal University of California, San Diego A Quantum computer is a device that uses uantum phenomenon to perform a computation. A classical system follows a single
More informationClaudio J. Tessone. Pau Amengual. Maxi San Miguel. Raúl Toral. Horacio Wio. Eur. Phys. J. B 39, 535 (2004) http://www.imedea.uib.
Horacio Wio Raúl Toral Eur. Phys. J. B 39, 535 (2004) Claudio J. Tessone Pau Amengual Maxi San Miguel http://www.imedea.uib.es/physdept Models of Consensus vs. Polarization, or Segregation: Voter model,
More informationSelf Organizing Maps: Fundamentals
Self Organizing Maps: Fundamentals Introduction to Neural Networks : Lecture 16 John A. Bullinaria, 2004 1. What is a Self Organizing Map? 2. Topographic Maps 3. Setting up a Self Organizing Map 4. Kohonen
More informationarxiv:1603.01211v1 [quant-ph] 3 Mar 2016
Classical and Quantum Mechanical Motion in Magnetic Fields J. Franklin and K. Cole Newton Department of Physics, Reed College, Portland, Oregon 970, USA Abstract We study the motion of a particle in a
More informationRandomization Approaches for Network Revenue Management with Customer Choice Behavior
Randomization Approaches for Network Revenue Management with Customer Choice Behavior Sumit Kunnumkal Indian School of Business, Gachibowli, Hyderabad, 500032, India sumit kunnumkal@isb.edu March 9, 2011
More informationON THE COMPLEXITY OF THE GAME OF SET. {kamalika,pbg,dratajcz,hoeteck}@cs.berkeley.edu
ON THE COMPLEXITY OF THE GAME OF SET KAMALIKA CHAUDHURI, BRIGHTEN GODFREY, DAVID RATAJCZAK, AND HOETECK WEE {kamalika,pbg,dratajcz,hoeteck}@cs.berkeley.edu ABSTRACT. Set R is a card game played with a
More informationBackbone and elastic backbone of percolation clusters obtained by the new method of burning
J. Phys. A: Math. Gen. 17 (1984) L261-L266. Printed in Great Britain LE ITER TO THE EDITOR Backbone and elastic backbone of percolation clusters obtained by the new method of burning H J HerrmanntS, D
More informationPath Selection Methods for Localized Quality of Service Routing
Path Selection Methods for Localized Quality of Service Routing Xin Yuan and Arif Saifee Department of Computer Science, Florida State University, Tallahassee, FL Abstract Localized Quality of Service
More informationConsider a problem in which we are given a speed function
Fast marching methods for the continuous traveling salesman problem June Andrews and J. A. Sethian* Department of Mathematics, University of California, Berkeley, CA 94720 Communicated by Alexandre J.
More informationThe Dynamics of a Genetic Algorithm on a Model Hard Optimization Problem
The Dynamics of a Genetic Algorithm on a Model Hard Optimization Problem Alex Rogers Adam Prügel-Bennett Image, Speech, and Intelligent Systems Research Group, Department of Electronics and Computer Science,
More informationReliability. 26.1 Reliability Models. Chapter 26 Page 1
Chapter 26 Page 1 Reliability Although the technological achievements of the last 50 years can hardly be disputed, there is one weakness in all mankind's devices. That is the possibility of failure. What
More information1 Simulating Brownian motion (BM) and geometric Brownian motion (GBM)
Copyright c 2013 by Karl Sigman 1 Simulating Brownian motion (BM) and geometric Brownian motion (GBM) For an introduction to how one can construct BM, see the Appendix at the end of these notes A stochastic
More informationJPEG compression of monochrome 2D-barcode images using DCT coefficient distributions
Edith Cowan University Research Online ECU Publications Pre. JPEG compression of monochrome D-barcode images using DCT coefficient distributions Keng Teong Tan Hong Kong Baptist University Douglas Chai
More informationMarket Risk Analysis. Quantitative Methods in Finance. Volume I. The Wiley Finance Series
Brochure More information from http://www.researchandmarkets.com/reports/2220051/ Market Risk Analysis. Quantitative Methods in Finance. Volume I. The Wiley Finance Series Description: Written by leading
More informationarxiv:1203.1525v1 [math.co] 7 Mar 2012
Constructing subset partition graphs with strong adjacency and end-point count properties Nicolai Hähnle haehnle@math.tu-berlin.de arxiv:1203.1525v1 [math.co] 7 Mar 2012 March 8, 2012 Abstract Kim defined
More informationEXIT TIME PROBLEMS AND ESCAPE FROM A POTENTIAL WELL
EXIT TIME PROBLEMS AND ESCAPE FROM A POTENTIAL WELL Exit Time problems and Escape from a Potential Well Escape From a Potential Well There are many systems in physics, chemistry and biology that exist
More informationarxiv:hep-lat/9210041v1 30 Oct 1992
1 The Interface Tension in Quenched QCD at the Critical Temperature B. Grossmann a, M.. aursen a, T. Trappenberg a b and U. J. Wiese c a HRZ, c/o Kfa Juelich, P.O. Box 1913, D-5170 Jülich, Germany arxiv:hep-lat/9210041v1
More informationInternational Journal of Information Technology, Modeling and Computing (IJITMC) Vol.1, No.3,August 2013
FACTORING CRYPTOSYSTEM MODULI WHEN THE CO-FACTORS DIFFERENCE IS BOUNDED Omar Akchiche 1 and Omar Khadir 2 1,2 Laboratory of Mathematics, Cryptography and Mechanics, Fstm, University of Hassan II Mohammedia-Casablanca,
More informationOUTLIER ANALYSIS. Data Mining 1
OUTLIER ANALYSIS Data Mining 1 What Are Outliers? Outlier: A data object that deviates significantly from the normal objects as if it were generated by a different mechanism Ex.: Unusual credit card purchase,
More informationMore Local Structure Information for Make-Model Recognition
More Local Structure Information for Make-Model Recognition David Anthony Torres Dept. of Computer Science The University of California at San Diego La Jolla, CA 9093 Abstract An object classification
More informationThe Quantum Harmonic Oscillator Stephen Webb
The Quantum Harmonic Oscillator Stephen Webb The Importance of the Harmonic Oscillator The quantum harmonic oscillator holds a unique importance in quantum mechanics, as it is both one of the few problems
More informationIntroduction to Quantum Computing
Introduction to Quantum Computing Javier Enciso encisomo@in.tum.de Joint Advanced Student School 009 Technische Universität München April, 009 Abstract In this paper, a gentle introduction to Quantum Computing
More informationMATHEMATICAL ENGINEERING TECHNICAL REPORTS. An Improved Approximation Algorithm for the Traveling Tournament Problem
MATHEMATICAL ENGINEERING TECHNICAL REPORTS An Improved Approximation Algorithm for the Traveling Tournament Problem Daisuke YAMAGUCHI, Shinji IMAHORI, Ryuhei MIYASHIRO, Tomomi MATSUI METR 2009 42 September
More informationHigh-dimensional labeled data analysis with Gabriel graphs
High-dimensional labeled data analysis with Gabriel graphs Michaël Aupetit CEA - DAM Département Analyse Surveillance Environnement BP 12-91680 - Bruyères-Le-Châtel, France Abstract. We propose the use
More informationPart 2: Analysis of Relationship Between Two Variables
Part 2: Analysis of Relationship Between Two Variables Linear Regression Linear correlation Significance Tests Multiple regression Linear Regression Y = a X + b Dependent Variable Independent Variable
More informationSwarm Intelligence Algorithms Parameter Tuning
Swarm Intelligence Algorithms Parameter Tuning Milan TUBA Faculty of Computer Science Megatrend University of Belgrade Bulevar umetnosti 29, N. Belgrade SERBIA tuba@ieee.org Abstract: - Nature inspired
More informationHow To Fix Out Of Focus And Blur Images With A Dynamic Template Matching Algorithm
IJSTE - International Journal of Science Technology & Engineering Volume 1 Issue 10 April 2015 ISSN (online): 2349-784X Image Estimation Algorithm for Out of Focus and Blur Images to Retrieve the Barcode
More informationLU Factorization Method to Solve Linear Programming Problem
Website: wwwijetaecom (ISSN 2250-2459 ISO 9001:2008 Certified Journal Volume 4 Issue 4 April 2014) LU Factorization Method to Solve Linear Programming Problem S M Chinchole 1 A P Bhadane 2 12 Assistant
More informationCloud Computing is NP-Complete
Working Paper, February 2, 20 Joe Weinman Permalink: http://www.joeweinman.com/resources/joe_weinman_cloud_computing_is_np-complete.pdf Abstract Cloud computing is a rapidly emerging paradigm for computing,
More informationChapter 1. NP Completeness I. 1.1. Introduction. By Sariel Har-Peled, December 30, 2014 1 Version: 1.05
Chapter 1 NP Completeness I By Sariel Har-Peled, December 30, 2014 1 Version: 1.05 "Then you must begin a reading program immediately so that you man understand the crises of our age," Ignatius said solemnly.
More informationJUST-IN-TIME SCHEDULING WITH PERIODIC TIME SLOTS. Received December May 12, 2003; revised February 5, 2004
Scientiae Mathematicae Japonicae Online, Vol. 10, (2004), 431 437 431 JUST-IN-TIME SCHEDULING WITH PERIODIC TIME SLOTS Ondřej Čepeka and Shao Chin Sung b Received December May 12, 2003; revised February
More informationGenetic Algorithm Based Interconnection Network Topology Optimization Analysis
Genetic Algorithm Based Interconnection Network Topology Optimization Analysis 1 WANG Peng, 2 Wang XueFei, 3 Wu YaMing 1,3 College of Information Engineering, Suihua University, Suihua Heilongjiang, 152061
More informationTHERE is a significant amount of current research activity
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 14, NO. 5, SEPTEMBER 2006 789 Stable Task Load Balancing Strategies for Cooperative Control of Networked Autonomous Air Vehicles Jorge Finke, Member,
More informationNotes on Factoring. MA 206 Kurt Bryan
The General Approach Notes on Factoring MA 26 Kurt Bryan Suppose I hand you n, a 2 digit integer and tell you that n is composite, with smallest prime factor around 5 digits. Finding a nontrivial factor
More information