Using Ridge Regression Method to Reduce Estimation Uncertainty in Chlorophyll Models Based on Worldview Multispectral Data

نظرا لما تعانيـه تجارب الخليط من مشكلة الارتبـاطات العالية ووجود مشكلة التعدد الخطي بين المتغيرات التوضيحية وذلك لوجود قيد الوحدة والتفاعلات بينها في النموذج مما يزيد من وجود الارتباطات بين المتغيرات النوضيحية وهذا ما يوضحه عامل تضخم التباين Variance Inflation Vector (VIF) , كذلك تم التطـرق الى استخـدام تحويل المكونات الزائفة للحـدود الدنيا (L-Pseudo component) للتقليل من الارتباطات بين مكونات الخليط . لتقدير معالم ٳنموذج الخليط اعتمدنا في بحثنا على استخدام طرائق تقدير تعمل على زيادة التحيز وتقلل من التباين منها طريقة ٳنحدار الحرف Ridge Regression Method وطريقة تقدير (Least Absolute Shrinkage and Selection Operator) (LASSO) فضلا عن طريقة تقدير الشبكة المرنة Elastic Net , وتمثيله باستخدام المحاكاة بلغة R بمعيار المقارنة متوسط مطلق الخطأ النسبي Mean Absolute Percentage Error (MAPE).

Download Full-text

Analysis and reduction of the geomagnetic gradient influence on aeromagnetic compensation in a towed bird

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-10-257-2021 ◽

2021 ◽

Vol 10 (2) ◽

pp. 257-264

Author(s):

Zhijian Zhou ◽

Zhilong Liu ◽

Wenduo Li ◽

Yihang Wang ◽

Chao Wang

Keyword(s):

Data Quality ◽

Field Gradient ◽

Ridge Regression ◽

Geomagnetic Field ◽

Regression Method ◽

Compensation Method ◽

Interference Model ◽

Flight Tests ◽

Important Method

Abstract. Aeromagnetic exploration is an important method of geophysical exploration. We study the compensation method of the towed bird system and establish the towed bird interference model. Due to the geomagnetic gradient changing greatly, the geomagnetic gradient is considered in the towed bird interference model. In this paper, we model the geomagnetic field gradient and analyze the influence of the towed bird system on the aeromagnetic compensation results. Finally, we apply the ridge regression method to solve the problem. We verify the feasibility of this compensation method through actual flight tests and further improve the data quality of the towed bird interference.

Download Full-text

Reliable home error identification of a 2-DOF parallel robot based on regularization methods

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406218791635 ◽

2018 ◽

Vol 233 (7) ◽

pp. 2502-2515

Author(s):

Jiangping Mei ◽

Jiawei Zang ◽

Yabin Ding

Keyword(s):

Kalman Filter ◽

Ridge Regression ◽

Parallel Robot ◽

Initial Position ◽

Regression Method ◽

Filter Method ◽

Filter Methods ◽

Curve Method ◽

Kalman Filter Method ◽

Active Link

This paper deals with the home error (the initial position error of active link) identification of a 2-DOF parallel robot. The identification model containing the home errors of the robot and the assembly errors of a new measuring instrument is developed using distance measurement. After that, an adaptive ridge regression method and a regularized Kalman filter method are proposed to improve the identification reliability and accuracy. Particularly, a modified L-curve method is proposed to provide suitable regularization parameters for the regularized Kalman filter. Based on the selected optimal measurement positions, experiments are carried out, in which the two regularized identification methods are compared with the ordinary ridge regression and the Kalman filter methods. Results show that the reliability and accuracy of the two methods are much better than the ordinary ridge regression method, and the divergence problem of the Kalman filter can be well resolved by the regularized Kalman filter.

Download Full-text