• Title/Summary/Keyword: IRLS

Search Result 19, Processing Time 0.02 seconds

An Efficient Implementation of Hybrid $l^1/l^2$ Norm IRLS Method as a Robust Inversion (강인한 역산으로서의 하이브리드 $l^1/l^2$ norm IRLS 방법의 효율적 구현기법)

  • Ji, Jun
    • Geophysics and Geophysical Exploration
    • /
    • v.10 no.2
    • /
    • pp.124-130
    • /
    • 2007
  • Least squares ($l^2$ norm) solutions of seismic inversion tend to be very sensitive to data points with large errors. The $l^1$ norm minimization gives more robust solutions, but usually with higher computational cost. Iteratively reweighted least squares (IRLS) method gives efficient approximate solutions of these $l^1$ norm problems. I propose an efficient implementation of the IRLS method for a hybrid $l^1/l^2$ minimization problem that behaves as $l^2$ norm fit for small residual and $l^1$ norm fit for large residuals. The proposed algorithm shows more robust characteristics to the decision of the threshold value than the l1 norm IRLS inversion does with respect to the threshold value to avoid singularity.

Iterative Least-Squares Method for Velocity Stack Inversion - Part A: IRLS method (속도중합역산을 위한 반복적 최소자승법 - Part A: IRLS 방법)

  • Ji Jun
    • Geophysics and Geophysical Exploration
    • /
    • v.8 no.2
    • /
    • pp.163-169
    • /
    • 2005
  • Recently, the velocity stack domain is having an attention as a very useful domain for various processing in seismic data processing. In order to be used in many applications, the velocity stack should be obtained through an inversion method and the used inversion should have properties like the robustness to noise and the parsimony of velocity stack result. Iteratively Reweighted Least-Squares (IRLS) method is the one of the inversion methods that have such properties. This paper describes the theoretical background, implementation of the method, and examines the characteristics and limits of the IRLS method.

Robust inversion of seismic data using ${\ell}^1/{\ell}^2$ norm IRLS method (${\ell}^1/{\ell}^2$ norm IRLS 방법을 사용한 강인한 탄성파자료역산)

  • Ji Jun
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2005.05a
    • /
    • pp.227-232
    • /
    • 2005
  • Least squares (${\ell}^2-norm$) solutions of seismic inversion tend to be very sensitive to data points with large errors. The ${\ell}^p-norm$ minimization for $1{\le}p<2$ gives more robust solutions, but usually with higher computational cost. Iteratively reweighted least squares (IRLS) gives efficient approximate solutions of these ${\ell}^p-norm$ problems. I propose a simple way to implement the IRLS method for a hybrid ${\ell}^1/{\ell}^2$ minimization problem that behaves as ${\ell}^2$ fit for small residual and ${\ell}^1$ fit for large residuals. Synthetic and a field-data examples demonstrates the improvement of the hybrid method over least squares when there are outliers in the data.

  • PDF

Iterative Least-Squares Method for Velocity Stack Inversion - Part B: CGG Method (속도중합역산을 위한 반복적 최소자승법 - Part B: CGG 방법)

  • Ji Jun
    • Geophysics and Geophysical Exploration
    • /
    • v.8 no.2
    • /
    • pp.170-176
    • /
    • 2005
  • Recently the velocity stack inversion is having many attentions as an useful way to perform various seismic data processing. In order to be used in various seismic data processing, the inversion method used should have properties such as robustness to noise and parsimony of the velocity stack result. The IRLS (Iteratively Reweighted Least-Squares) method that minimizes ${L_1}-norm$ is the one used mostly. This paper introduce another method, CGG (Conjugate Guided Gradient) method, which can be used to achieve the same goal as the IRLS method does. The CGG method is a modified CG (Conjugate Gradient) method that minimizes ${L_1}-norm$. This paper explains the CGG method and compares the result of it with the one of IRSL methods. Testing on synthetic and real data demonstrates that CGG method can be used as an inversion method f3r minimizing various residual/model norms like IRLS methods.

The Study on Effect of Korean Medical Treatment for Patients with Restless Legs Syndrome (하지불안증후군 환자에 대한 한의학적 치료 효과에 대한 연구)

  • Lee, Yu-Jin;Lee, Jae-Eun;Kim, Soo-Jin;Yoo, Jong-Ho
    • Journal of Oriental Neuropsychiatry
    • /
    • v.26 no.4
    • /
    • pp.357-364
    • /
    • 2015
  • Objectives: The purpose of this study was to examine the effects of Korean medical treatment for Restless Legs Syndrome (RLS). Methods: We examined the effects of Korean medical treatment for patients with RLS who visited the neuropsychiatric clinic of Korean medicine. We treated the patient with herbal-medication, acupuncture, oriental psychotherapy. IRLS, STAI-X1,X2, BDI-2, BAI, STAXI-S,T were compared before and after 4 and 8 weeks of treatment to determine whether the symptoms and mood of patients were improved. Results: After 4 weeks treatment (n=13), STAI-X1,X2, BDI-2, BAI, STAXI-S scores increased significantly; whereas, IRLS and STAXI-T scores decreased. After 8 weeks treatment (n=8), IRLS, STAI-X1,X2, BDI-2, BAI scores increased significantly; whereas, STAXI-S scores decreased.Conclusions The treatment of RLS with Korean medicine was clinically efficient and resulted in improvement of the symptoms as well as psychological problems.

Effect of Acupuncture and Massage on Iliopsoas Muscle in Patients with Restless Leg Syndrome : Case Report (장요근 침치료와 마사지로 호전된 하지불안증후군 환자 치험례)

  • Park, Won-Hyung;Cha, Yun-Yeop
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.23 no.2
    • /
    • pp.163-174
    • /
    • 2013
  • Restless legs syndrome(RLS) is a neurological disorder characterized by an irresistible urge to move legs to stop uncomfortable or odd sensations. We report a new approach to improve RLS using acupuncture and massage on iliopsoas Muscle. The patients who have RLS were treated by acupuncture and massage on iliopsoas Muscle. We measured 3~6 times IRLS(Korean Versoin of International Restless Legs Scale), VAS(visual analogue scale), and angle(between the legs and the table) during the treatment period. After treatment, RLS symptoms decreased, In case 1, IRLS changed 34 to 10, VAS changed 8 to 2, angle changed 20 to 5. In case 2, IRLS changed 22 to 12, VAS changed 10 to 5, angle changed 15 to 10. In case 3, IRLS changed 30 to 9, VAS changed 8 to 1, angle changed 25 to 5. Acupuncture and massage on iliopsoas muscle for RLS was effective. To effective acupuncture treatment for RLS, more research is needed.

A Framework for Inteligent Remote Learning System

  • 유영동
    • The Journal of Information Systems
    • /
    • v.2
    • /
    • pp.194-206
    • /
    • 1993
  • Intelligent remote learning system is a system that incorporate communication technology and others : a database engine, an intelligent tutorial system. Learners can study by themselves through the intelligent tutorial system. The existence of a communication, database and artificial intelligence enhance the capability of IRLS. According to Parsaye, an intelligent databases should have the following features : 1) Knowledge discovery. 2) Data integrity and quality control. 3) Hypermedia management. 4) Data presentation and display. 5) Decision support and scenario analysis. 6) Data format management. 7) Intelligent system design tools. I hope that this research of framework for IRLS paves for the future research. As mentioned in the above, the future work will include an intelligent database, self-learning mechanism using neural network.

  • PDF

A Study on the ISAR Image Reconstruction Algorithm Using Compressive Sensing Theory under Incomplete RCS Data (데이터 손실이 있는 RCS 데이터에서 압축 센싱 이론을 적용한 ISAR 영상 복원 알고리즘 연구)

  • Bae, Ji-Hoon;Kang, Byung-Soo;Kim, Kyung-Tae;Yang, Eun-Jung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.25 no.9
    • /
    • pp.952-958
    • /
    • 2014
  • In this paper, we propose a parametric sparse recovery algorithm(SRA) applied to a radar signal model, based on the compressive sensing(CS), for the ISAR(Inverse Synthetic Aperture Radar) image reconstruction from an incomplete radar-cross-section(RCS) data and for the estimation of rotation rate of a target. As the SRA, the iteratively-reweighted-least-square(IRLS) is combined with the radar signal model including chirp components with unknown chirp rate in the cross-range direction. In addition, the particle swarm optimization(PSO) technique is considered for searching correct parameters related to the rotation rate. Therefore, the parametric SRA based on the IRLS can reconstruct ISAR image and estimate the rotation rate of a target efficiently, although there exists missing data in observed RCS data samples. The performance of the proposed method in terms of image entropy is also compared with that of the traditional interpolation methods for the incomplete RCS data.

A Case Report of Patient with Restless Legs Syndrome Improved by Gami Ssanghwa-tang (가미쌍화탕으로 호전된 하지불안증후군 환자 치험 1례)

  • Yim, Tae-Bin;Jeon, Gyu-Ri;Lee, Hye-Jin;Kim, Seo-Young;Cho, Seung-Yeon;Park, Seong-Uk;Ko, Chang-Nam;Park, Jung-Mi
    • The Journal of the Society of Stroke on Korean Medicine
    • /
    • v.22 no.1
    • /
    • pp.1-10
    • /
    • 2021
  • ■ Objectives The purpose of this case study is to report the effectiveness of Gami Ssanghwa-tang on the restless legs syndrome patient. ■ Methods The patient was treated with Korean medicine, including herbal medication Gami Ssanghwa-tang for 26 days and acupuncture for once a week as an out patient. The evaluation was performed using the Korean versions of the International Restless Legs Scale(K-IRLS). ■ Results After 34 days of treatment, the K-IRLS total score improved from 24 to 8. And at the follow up session(7 days after end of treatment), the K-IRLS total score improved to 0. ■ Conclusion This study suggested that herbal medicine, Gami Ssanghwa-tang might be effective in Restless legs syndrome.

A Case of Restless Legs Syndrome Patient with Numbness in Both Soles Using Gyejibokryeong-hwan (하지불안증후군으로 인한 양 발바닥 저림에 대한 한의 치험 1례)

  • Yang, Jung-yun;Kim, Se-won;Lee, Yu-jin;Cho, Ki-ho;Moon, Sang-kwan;Jung, Woo-sang;Kwon, Seung-won
    • The Journal of Internal Korean Medicine
    • /
    • v.40 no.2
    • /
    • pp.270-278
    • /
    • 2019
  • Objective: In this case report, we address the case of a 68-year-old woman with numbness in both soles due to restless legs syndrome. Methods: A patient was treated with Korean medicine including herbal medication Gyejibokryeong-hwan during 73 days as an outpatient. We evaluated the improvements of symptoms by use of the International Restless Legs Scale (IRLS) and checking subjective symptoms of patient. Results: After 73 days of Korean medicine treatment, there was improvement in patient's symptoms. IRLS score improved from 12 to 8, and subjective symptoms improved to about 30% compared to the first time. Conclusions: This study suggested that Korean medicine treatments might be effective in RLS patient recovery.