12,143 Hits in 1.8 sec

Phase transition and landscape statistics of the number partitioning problem

Peter F. Stadler, Wim Hordijk, José F. Fontanari
2003 Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics  
In adddition, we show that the barrier trees associated with the NPP are very similar to random trees, contrasting dramatically with trees associated with the p spin-glass and random energy models.  ...  We also examine critically a recent conjecture on the equivalence between the NPP and a truncated random energy model.  ...  cost barriers between these optima.  ... 
doi:10.1103/physreve.67.056701 pmid:12786316 fatcat:2kxvthdodnchrgyvhkp22ksvva

Cost-Effectiveness of Newer Antiretroviral Drugs in Treatment-Experienced Patients With Multidrug-Resistant HIV Disease

Ahmed M. Bayoumi, Paul G. Barnett, Vilija R. Joyce, Susan C. Griffin, Huiying Sun, Nick J. Bansback, Mark Holodniy, Gillian Sanders, Sheldon T. Brown, Tassos C. Kyriakides, Brian Angus, D. William Cameron (+3 others)
2013 Journal of Acquired Immune Deficiency Syndromes  
The effectiveness of newer drugs (those approved in 2005 or later) was estimated from published randomized trials. Other parameters were estimated from a randomized trial and from the literature.  ...  OPTIMA Trial Our primary source of data to model the clinical course of advanced multi-drug resistant HIV was the OPTIMA trial. 1 OPTIMA evaluated two treatment approaches -structured treatment interruption  ...  Analysis For the probabilistic sensitivity analysis, we randomly sampled model parameters from distributions to estimate overall model uncertainty and to calculate the expected value of perfect information  ... 
doi:10.1097/qai.0000000000000002 pmid:24129369 pmcid:PMC3932156 fatcat:ymxxhhdndfewxovqn2efwbctly

Investigating Quantum Approximate Optimization Algorithms under Bang-bang Protocols [article]

Daniel Liang, Li Li, Stefan Leichenauer
2020 arXiv   pre-print
We investigate the effects of changing the initial conditions of the SD algorithm, and see that better local optima can be found by using an adiabatic initialization.  ...  Using a randomized greedy optimizer for protocol performance called Stochastic Descent (SD), we investigate the performance of bang-bang QAOA on MAX-2-SAT, finding the appearance of phase transitions with  ...  What this effectively means is that the distance from a random protocol to its nearby local optima decreases with T regardless of the three starting positions.  ... 
arXiv:2005.13103v2 fatcat:ndlx5hfevbapnalobogiovoyby

Revisiting the big valley search space structure in the TSP

D R Hains, L D Whitley, A E Howe
2011 Journal of the Operational Research Society  
is very close to that of the global optimum; multiple funnels appear around local optima with evaluations close to the global optimum.  ...  We examine the big-valley hypothesis more closely and show that while the big-valley structure does appear in much of the solution space, it breaks down around local optima that have solutions whose evaluation  ...  The random walk method A random walk method is used to explore the space of local optima near the global.  ... 
doi:10.1057/jors.2010.116 fatcat:n7flqb4c6nf57m67yzdazrzudm

Understanding Phase Transitions with Local Optima Networks: Number Partitioning as a Case Study [chapter]

Gabriela Ochoa, Nadarajen Veerapen, Fabio Daolio, Marco Tomassini
2017 Lecture Notes in Computer Science  
Using the local optima network model, we analyse a number of instances before, during, and after the phase transition.  ...  Easy instances feature a single or a small number of dominant funnels leading to global optima; hard instances have a large number of suboptimal funnels attracting the search.  ...  , the number of perfect partitions drops to zero with probability tending to 1 [5] .  ... 
doi:10.1007/978-3-319-55453-2_16 fatcat:c7yt5f427vbjlkowa5jnzan7ee

Varimax Rotation Based on Gradient Projection Is a Feasible Alternative to SPSS

Anneke Cleopatra Weide, André Beauducel
2019 Frontiers in Psychology  
In a simulation study, we tested whether GPR-Varimax yielded multiple local solutions by creating population simple structure with a single optimum and with two optima, a global and a local one (double-optimum  ...  GPR-Varimax was conducted with unrotated and multiple (q = 1, 10, 50, and 100) random start loadings. We found equal results for GPR-Varimax and SPSS-Varimax in most conditions.  ...  Therefore, the double-optimum model constitutes a more challenging test of local optima in GPR-Varimax than the single-optimum model of perfect simple structure.  ... 
doi:10.3389/fpsyg.2019.00645 pmid:30971985 pmcid:PMC6443893 fatcat:44ftqvpz55chtodnpwq7anappe

Page 1800 of Mathematical Reviews Vol. , Issue 96c [page]

1996 Mathematical Reviews  
all local optima have guaranteed quality with respect to global optima.  ...  Summary: “We show that the class of perfect graphs known as split graphs can be efficiently recognized in a parallel process environment.  ... 

Decision Theory and Analysis: An Optima Value Creation Precursor for Organizations

Cephas A. Gbande, Paul T. Akuhwa
2015 Open Journal of Applied Sciences  
The decision-maker uses probability values to convert uncertainties and risks into perfect knowledge poles so as to make informed decisions.  ...  For an optima value creation, this paper is succinct that a robust decision theory and analysis serve as a precursor.  ...  Since at least one decision variable is random, the independent variable(s), will also be random.  ... 
doi:10.4236/ojapps.2015.57036 fatcat:wnmwjndnc5gu5boztc2ulud4ly

Mapping MOS-HIV to HUI3 and EQ-5D-3L in Patients With HIV

Vilija R. Joyce, Huiying Sun, Paul G. Barnett, Nick Bansback, Susan C. Griffin, Ahmed M. Bayoumi, Aslam H. Anis, Mark Sculpher, William Cameron, Sheldon T. Brown, Mark Holodniy, Douglas K. Owens
2017 MDM Policy & Practice  
The design and main findings have been reported previously. 26, 27 Briefly, OPTIMA was a 2 3 2 factorial randomized clinical trial that randomized 368 multidrug-resistant HIV-infected patients to an  ...  health) and any differences they have compared to those with less than perfect health.  ... 
doi:10.1177/2381468317716440 pmid:30288427 pmcid:PMC6125043 fatcat:3sdsctjzhbh43nzig4v5yc3yrq

An optimization algorithm for multimodal functions inspired by collective animal behavior [article]

Erik Cuevas, Mauricio Gonzalez
2014 arXiv   pre-print
Interest in multimodal function optimization is expanding rapidly since real world optimization problems often demand locating multiple optima within a search space.  ...  Experimental results demonstrate that the proposed algorithm is capable of finding global and local optima of benchmark multimodal optimization problems with a higher efficiency in comparison to other  ...  [10] ) and the musical process of searching for a perfect state of harmony (proposed by Geem et al. [11] , Lee and Geem [12] , Geem [13] and Gao et al. [14] ).  ... 
arXiv:1406.7811v1 fatcat:nlpyczc7qjfbfcujffperxdjzy

A search space enhanced modified whale optimization algorithm for feature selection in large-scale microarray datasets

M Sathya, Dept. of CS, Karpagam Academy of Higher Education, Coimbatore, 641021, India
2020 Indian Journal of Science and Technology  
Levy flight which employs for acceleration convergence speed of SMWOA andalso holds the result from local optima builds up by the population assortment.A quadratic interpolation takes up the exploitation  ...  results a random search.  ...  During phase of exploration SMWOA is as follows, X (t + 1) =    X (t) + 1 sqrt (t) × sign (random − 0.5) ⊕ Levy, i f p < 0.5 D ′ × e bl × cos (2πl) + X * (t) , i f p ≥ 0.5 (3.13) Maintaining perfect  ... 
doi:10.17485/ijst/v13i42.767 fatcat:pqfzmlulrfdrlklsjf5olwitcy

Landscape Analysis of a Class of NP-Hard Binary Packing Problems

Khulood Alyahya, Jonathan E. Rowe
2018 Evolutionary Computation  
Unlike existing studies of these problems, we study instances generated at random from various distributions.  ...  NPP undergoes a sudden phase transition from solvability (a perfect partition exist) to insolvability (a perfect partition doesn't exist), determined by the control parameter k = log 2 (M )/n, which corresponds  ...  , the number of perfect partitions drops to zero with probability tending to 1 (Borgs et al., 2001) .  ... 
doi:10.1162/evco_a_00237 pmid:30365387 fatcat:kc4cs44ssvfsfcmkpdpofaiuvq

Analyzing the landscape of a graph based hyper-heuristic for timetabling problems

Gabriela Ochoa, Rong Qu, Edmund K. Burke
2009 Proceedings of the 11th Annual conference on Genetic and evolutionary computation - GECCO '09  
A value of = −1.0 ( = 1.0) for maximisation (minimisation) problems indicates a perfect correlation between fitness and distance to the optimum, and thus predicts an easy search.  ...  St impr : the minimum, maximum, average, and standard deviation of the number of improvement 2 steps in the local search process (from random initial solutions to local optima).  ... 
doi:10.1145/1569901.1569949 dblp:conf/gecco/OchoaQB09 fatcat:ikevmi6spnf47conueqcpnh7q4

Large neighborhood local search for the p-median problem

Yuri Kochetov, Tatyana Levanova, Ekaterina Alekseeva, Maxim Loresh
2005 Yugoslav Journal of Operations Research  
The number of perfect codes ℵ(k) grows exponentially as k increases.  ...  the number of local optima obtained with fixed values of , i i I α ∈ ; K : the number of local optima which used to update of , Table 1 : 1 Average relative error for the algorithms with Swap neighborhoodTable  ...  As we can see, a path from starting points to local optima is shot enough. CONCLUSIONS In this paper we have introduced a new promising neighborhood for the pmedian problem.  ... 
doi:10.2298/yjor0501053k fatcat:ngxsp2vb6zeudoou7qjohvob4i

Characterizing Local Optima for Maximum Parsimony

Ellen Urheim, Eric Ford, Katherine St. John
2016 Bulletin of Mathematical Biology  
When Nearest Neighbor Interchange (NNI) operations are used, multiple local optima can occur even for "perfect" sequence data, which results in hill-climbing searches that never reach a global optimum.  ...  We quantify the occurrence of such optima for well-behaved sets of data.  ...  The proof of the SPR result suggests that search heuristics that allow moves that can join arbitrary subtrees (like SPR or TBR) or allow a random search (to escape non-global optima of NNI) yield search  ... 
doi:10.1007/s11538-016-0174-0 pmid:27234257 fatcat:h4lypshx6vdhlflg2a43ibby6a
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