Acceleration of spoken term detection using a suffix array by assigning optimal threshold values to sub-keywords

2013 ◽  
Author(s):  
Kouichi Katsurada ◽  
Seiichi Miura ◽  
Kheang Seng ◽  
Yurie Iribe ◽  
Tsuneo Nitta
Keyword(s):  
Suffix Array ◽  
Optimal Threshold ◽  
Threshold Values ◽  
Spoken Term Detection

Evaluation of fast spoken term detection using a suffix array

2011 ◽  
Author(s):  
Kouichi Katsurada ◽  
Shinta Sawada ◽  
Shigeki Teshima ◽  
Yurie Iribe ◽  
Tsuneo Nitta
Keyword(s):  
Suffix Array ◽  
Spoken Term Detection

scholarly journals A Global Multilevel Thresholding Using Differential Evolution Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-23 ◽  
Author(s):  
Kanjana Charansiriphaisan ◽  
Sirapat Chiewchanwattana ◽  
Khamron Sunat
Keyword(s):  
Differential Evolution ◽  
Search Algorithm ◽  
Threshold Value ◽  
Optimal Threshold ◽  
Threshold Values ◽  
New Mutation ◽  
Bee Colony ◽  
Mutation Strategy ◽  
Otsu’S Function ◽  
Evolution Approach

Otsu’s function measures the properness of threshold values in multilevel image thresholding. Optimal threshold values are necessary for some applications and a global search algorithm is required. Differential evolution (DE) is an algorithm that has been used successfully for solving this problem. Because the difficulty of a problem grows exponentially when the number of thresholds increases, the ordinary DE fails when the number of thresholds is greater than 12. An improved DE, using a new mutation strategy, is proposed to overcome this problem. Experiments were conducted on 20 real images and the number of thresholds varied from 2 to 16. Existing global optimization algorithms were compared with the proposed algorithms, that is, DE, rank-DE, artificial bee colony (ABC), particle swarm optimization (PSO), DPSO, and FODPSO. The experimental results show that the proposed algorithm not only achieves a more successful rate but also yields a lower threshold value distortion than its competitors in the search for optimal threshold values, especially when the number of thresholds is large.

2D Direction Histogram-Based Rényi Entropic Multilevel Thresholding

2018 ◽  
Vol 22 (3) ◽  
pp. 369-379 ◽  
Author(s):  
Adiljan Yimit ◽  
◽  
Yoshihiro Hagihara
Keyword(s):  
Computation Time ◽  
Image Features ◽  
Optimal Threshold ◽  
Multilevel Thresholding ◽  
Threshold Values ◽  
Swarm Optimization ◽  
Bee Colony ◽  
Local Image ◽  
2D Histogram ◽  
Local Image Features

2D histogram-based thresholding methods, in which the histogram is computed from local image features, have better performance than 1D histogram-based methods, but they take much more computation time. In this paper, we present a Rényi entropic multilevel thresholding (REMT) method based on a 2D direction histogram constructed from pixel values and local directional features. In addition to presenting a fast recursive method for REMT, we propose the Rényi entropic artificial bee colony multilevel thresholding (REABCMT) method to quickly find the optimal threshold values. In order to demonstrate the efficacy of REABCMT, three versions of this method are compared in terms of computation time and optimal threshold values. In addition, the segmentation performance of REABCMT is also evaluated by comparing it with two other methods to show its effectiveness. Moreover, in order to evaluate the efficiency and stability of using the ABC algorithm in the search for threshold values, genetic algorithm (GA) and particle swarm optimization (PSO), two common optimization algorithms, are also compared with it.

Design of high efficient 3-level LINC transmitter using a 9-point finite difference method

2015 ◽  
Vol 8 (3) ◽  
pp. 521-527
Author(s):  
Jonggyun Lim ◽  
Hyunchul Ku
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Power Efficiency ◽  
Average Power ◽  
Optimal Threshold ◽  
Threshold Values ◽  
High Efficient ◽  
Dynamic Biasing ◽  
Low Efficiency

An efficiency of linear amplification with nonlinear components (LINC) system is degraded due to the low efficiency of a power combiner for high peak-to-average power ratio signals such as long-term evolution signal. A multi-level LINC system can be used to improve the performance of the conventional LINC system. In this paper, a novel 9-point finite difference method to determine the optimal threshold values for 3-level LINC system is suggested. Instead of solving the complicated differential equation, the proposed method can extract optimal threshold values efficiently by numerical method. The 3-level LINC system adopting the proposed scheme and dynamic biasing significantly improves the power efficiency and linear performance simultaneously. The proposed system is verified by comparing the performance of the 3-level system with those of the conventional and 2-level LINC systems.

scholarly journals A Different Approach for Choosing a Threshold in Peaks over Threshold

2020 ◽  
Vol 9 (4) ◽  
pp. 838-848
Author(s):  
Andrehette Verster ◽  
Lizanne Raubenheimer
Keyword(s):  
Bayesian Approach ◽  
Posterior Distribution ◽  
Visual Inspection ◽  
Extreme Value ◽  
Optimal Threshold ◽  
Extreme Value Index ◽  
Threshold Values ◽  
Peaks Over Threshold ◽  
Generalized Model

In Extreme Value methodology the choice of threshold plays an important role in efficient modelling of observations exceeding the threshold. The threshold must be chosen high enough to ensure an unbiased extreme value index but choosing the threshold too high results in uncontrolled variances. This paper investigates a generalized model that can assist in the choice of optimal threshold values in the γ positive domain. A Bayesian approach is considered by deriving a posterior distribution for the unknown generalized parameter. Using the properties of the posterior distribution allows for a method to choose an optimal threshold without visual inspection.

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