Performance Enhancement of a Delay-Based Reservoir Computing System by Using Gradient Boosting Technology

Jun-Yao Tao,Xiang-Sheng Tan,Zheng-Mao Wu,Guang-Qiong Xia,Dian-Zuo Yue,Qing-Qing Zeng

doi:10.1109/access.2020.3017636

Jun-Yao Tao, Xiang-Sheng Tan + Show 4 more

Open Access

https://doi.org/10.1109/access.2020.3017636

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Abstract

Gradient boosting technology has been proved to be an effective scheme for enhancing the performances of spatially distributed reservoir computing (RC) systems. In this work, a gradient boosting scheme by combining two reservoirs is proposed and numerically investigated in a delayed-based RC system. The original reservoir in the delayed-based RC system is a vertical-cavity surface-emitting laser (VCSEL) under polarization-rotated optical feedback (PR-OF), and it is trained on the desired output. The other VCSEL under PR-OF or polarization-preserved optical feedback (PP-OF) is supplemented to be an extra reservoir, which is trained on the remaining error of the original reservoir. Via Santa-Fe time series prediction task and 10th-order nonlinear autoregressive moving average (NARMA10) task, the performances of the delay-based RC system are evaluated before and after supplementing the extra reservoir, and then the effectiveness of the gradient boosting technology in the delayed RC system can be analyzed. The simulated results demonstrate that adopting gradient boosting technology is effective in a delay-based RC system. Comparatively speaking, the enhanced effect is more obvious under taking a VCSEL with PR-OF as the extra reservoir.

Highlights

With lots of information and data abounding in the current age, various efficient information processing technologies have been successively explored [1]
Vatin et al theoretically and experimentally investigated a reservoir computing (RC) system based on a vertical-cavity surface-emitting laser (VCSEL) under optical feedback, and the results demonstrated that the RC system can yield better performance when X polarization component (X-PC) and Y polarization component (Y-PC) in the VCSEL are simultaneously stimulated [26]
The top row corresponds the original reservoir operating at point A (B) in Fig. 2(a), and the left column is for the polarization-rotated optical feedback (PR-OF) (PP-OF) frame adopted in the extra reservoir

Summary

INTRODUCTION

With lots of information and data abounding in the current age, various efficient information processing technologies have been successively explored [1]. Freiberger et al demonstrated that the performance of such spatially distributed photonic RC system can be further enhanced by combining two (or more) reservoirs into a gradient boosting approach [9], where only the first reservoir is trained on the desired output and the others are trained to correct the remaining errors of the front reservoirs. In order to overcome these issues, photonic delay-based RC systems are proposed and investigated, in which the reservoirs are based on a single nonlinear node under time-delayed feedback [10]-[12]. Considering that the gradient boosting technology has been proven to be an effective method for improving the performances in spatially distributed RC systems, we will inspect whether such a technology is be effective for enhancing the performance of delay-based RC systems in this work. Speaking, the enhanced effect is more obvious under taking a VCSEL with PR-OF as the extra reservoir

SYSTEM AND METHODS

THEORY MODEL

RESULTS AND DISCUSSION

CONCLUSION