The Experts below are selected from a list of 3867 Experts worldwide ranked by ideXlab platform
Kenji Shimada - One of the best experts on this subject based on the ideXlab platform.
-
objective function effect based pattern search theoretical framework inspired by 3d component layout
Journal of Mechanical Design, 2007Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—Theoretical Framework Inspired by 3D Component Layout
Journal of Mechanical Design, 2006Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—An Implementation for 3D Component Layout
Journal of Mechanical Design, 2005Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Generalized pattern search (GPS) algorithms have been used successfully to solve three-dimensional (3D) component layout problems. These algorithms use a set of patterns and successively decreasing step sizes of these patterns to explore the search space before converging to good local minima. A shortcoming of conventional GPS algorithms is the lack of recognition of the fact that patterns affect the objective function by different amounts and hence it might be efficient to introduce them into the search in a certain order rather than introduce all of them at the beginning of the search. To address this shortcoming, it has been shown by the authors in previous work that it is more efficient to schedule patterns in decreasing order of their effect on the objective function. The effect of the patterns on the objective function was estimated by the a Priori Expectation of the objective function change due to the patterns. However computing the a Priori Expectation is expensive, and to practically implement the scheduling of patterns, an inexpensive estimate of the effect on the objective function is necessary. This paper introduces a metric for geometric layout called the sensitivity metric that is computationally inexpensive, to estimate the effect of pattern moves on the objective function. A new pattern search algorithm that uses the sensitivity metric to schedule patterns is shown to perform as well as the pattern search algorithm that used the a Priori Expectation of the objective function change. Though the sensitivity metric applies to the class of geometric layout or placement problems, the foundation and approach is useful for developing metrics for other optimization problems.
Chandankumar Aladahalli - One of the best experts on this subject based on the ideXlab platform.
-
objective function effect based pattern search theoretical framework inspired by 3d component layout
Journal of Mechanical Design, 2007Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—Theoretical Framework Inspired by 3D Component Layout
Journal of Mechanical Design, 2006Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—An Implementation for 3D Component Layout
Journal of Mechanical Design, 2005Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Generalized pattern search (GPS) algorithms have been used successfully to solve three-dimensional (3D) component layout problems. These algorithms use a set of patterns and successively decreasing step sizes of these patterns to explore the search space before converging to good local minima. A shortcoming of conventional GPS algorithms is the lack of recognition of the fact that patterns affect the objective function by different amounts and hence it might be efficient to introduce them into the search in a certain order rather than introduce all of them at the beginning of the search. To address this shortcoming, it has been shown by the authors in previous work that it is more efficient to schedule patterns in decreasing order of their effect on the objective function. The effect of the patterns on the objective function was estimated by the a Priori Expectation of the objective function change due to the patterns. However computing the a Priori Expectation is expensive, and to practically implement the scheduling of patterns, an inexpensive estimate of the effect on the objective function is necessary. This paper introduces a metric for geometric layout called the sensitivity metric that is computationally inexpensive, to estimate the effect of pattern moves on the objective function. A new pattern search algorithm that uses the sensitivity metric to schedule patterns is shown to perform as well as the pattern search algorithm that used the a Priori Expectation of the objective function change. Though the sensitivity metric applies to the class of geometric layout or placement problems, the foundation and approach is useful for developing metrics for other optimization problems.
Jonathan Cagan - One of the best experts on this subject based on the ideXlab platform.
-
objective function effect based pattern search theoretical framework inspired by 3d component layout
Journal of Mechanical Design, 2007Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—Theoretical Framework Inspired by 3D Component Layout
Journal of Mechanical Design, 2006Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Though pattern search algorithms have been successfully applied to three-dimensional (3D) component layout problems, a number of unanswered questions remain regarding their parameter tuning. One such question is the scheduling of patterns in the search. Current pattern search methods treat all patterns similarly and all of them are active from the beginning to the end of the search. Observations from 3D component layout motivate the question whether patterns should be introduced in some different order during the search. This paper presents a novel method for scheduling patterns that is inspired by observations from 3D component layout problems. The new method introduces patterns into the search in the decreasing order of a Priori Expectation of the objective function change due to the patterns. Pattern search algorithms based on the new pattern schedule run 30% faster on average than conventional pattern search based algorithms on 3D component layout problems and general 2D multimodal surface minimization problems. However since determining the expected change in objective function value due to the patterns is expensive, we explore approximations using domain information.
-
Objective Function Effect Based Pattern Search—An Implementation for 3D Component Layout
Journal of Mechanical Design, 2005Co-Authors: Chandankumar Aladahalli, Jonathan Cagan, Kenji ShimadaAbstract:Generalized pattern search (GPS) algorithms have been used successfully to solve three-dimensional (3D) component layout problems. These algorithms use a set of patterns and successively decreasing step sizes of these patterns to explore the search space before converging to good local minima. A shortcoming of conventional GPS algorithms is the lack of recognition of the fact that patterns affect the objective function by different amounts and hence it might be efficient to introduce them into the search in a certain order rather than introduce all of them at the beginning of the search. To address this shortcoming, it has been shown by the authors in previous work that it is more efficient to schedule patterns in decreasing order of their effect on the objective function. The effect of the patterns on the objective function was estimated by the a Priori Expectation of the objective function change due to the patterns. However computing the a Priori Expectation is expensive, and to practically implement the scheduling of patterns, an inexpensive estimate of the effect on the objective function is necessary. This paper introduces a metric for geometric layout called the sensitivity metric that is computationally inexpensive, to estimate the effect of pattern moves on the objective function. A new pattern search algorithm that uses the sensitivity metric to schedule patterns is shown to perform as well as the pattern search algorithm that used the a Priori Expectation of the objective function change. Though the sensitivity metric applies to the class of geometric layout or placement problems, the foundation and approach is useful for developing metrics for other optimization problems.
Emmanuel Dele Balogun - One of the best experts on this subject based on the ideXlab platform.
-
determinants of west african monetary zone wamz countries global export trade do foreign reserves and independent exchange rates matter
MPRA Paper, 2009Co-Authors: Emmanuel Dele BalogunAbstract:This study examines the effect of independent exchange rate pursuits and reserve holdings, relative to other determinants, on global export performance of WAMZ countries. The regression results show that exports originating from the Zone to the rest of the world are influenced positively by domestic output, export prices and exchange rate devaluations, but negatively by import price and economic performance of the major global trading partner, proxied by the US GDP. This result is not universal as the Gambia, Ghana and Guinea total exports functions show that exchange rate policy penalized exports contrary to the Nigerian case in which the coefficient estimate is significant and positive. The study infers that these results are consistent with theoretical Expectation given the ironical divergence in export basket. Although they are all primary commodity exporters, Nigeria’s exports is mainly crude oil, and a Priori Expectation is that rapid economic growth or booms in the US should lead to increased demand for energy (healthy competitions). In conclusion, the study infers that since independent flexible exchange rate policy pursuits and reserve holdings makes no difference to the Zonal export performance ex ante, but have great potential for global exports collectively, they could explore an OCA to enhance both intra- and global inter-regional export trade
-
Exchange rate policy and export performance of WAMZ countries
2007Co-Authors: Emmanuel Dele BalogunAbstract:This study examines the effect of independent exchange rate policy, relative to other determinants, on global export performance of WAMZ countries. The regression results show that exports originating from the Zone to the rest of the world are influenced positively by domestic output, export prices and exchange rate devaluations, but negatively by import price and economic performance of the major global trading partner, proxied by the US GDP. This result is not universal as the Gambia, Ghana and Guinea total exports functions show that exchange rate policy penalized exports contrary to the Nigerian case in which the coefficient estimate is significant and positive. The study infers that these results are consistent with theoretical Expectation given the ironical divergence in export basket. Although they are all primary commodity exporters, Nigeria’s exports is mainly crude oil, and a Priori Expectation is that rapid economic growth or booms in the US should lead to increased demand for energy (healthy competitions). In conclusion, the study infers that since independent flexible exchange rate policy makes no difference to the Zonal export performance ex ante, but have great potential for global exports collectively, they could explore an OCA to enhance both intra- and global inter-regional export trade.
S. Das Sarma - One of the best experts on this subject based on the ideXlab platform.
-
Generic quantized zero-bias conductance peaks in superconductor-semiconductor hybrid structures
Physical Review B, 2020Co-Authors: Haining Pan, William S. Cole, Jay D. Sau, S. Das SarmaAbstract:We show theoretically that quantized zero-bias conductance peaks should be ubiquitous in superconductor-semiconductor hybrids by employing a zero-dimensional random matrix model with continuous tuning parameters. We demonstrate that a normal metal-superconductor (NS) junction conductance spectra can be generically obtained in this model replicating all features seen in recent experimental results. The theoretical quantized conductance peaks, which explicitly do not arise from spatially isolated Majorana zero modes, are easily found by preparing a contour plot of conductance over several independent tuning parameters, mimicking the effect of Zeeman splitting and voltages on gates near the junction. This suggests that, even stable apparently quantized conductance peaks need not correspond to isolated Majorana modes; rather, the $\textit{a Priori}$ Expectation should be that such quantized peaks generically occupy a significant fraction of the high-dimensional tuning parameter space that characterizes the NS tunneling experiments.