• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.922-928
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• 2007

This paper presents the fast adaptive algorithm which applies an approximation scheme into RLS algorithm. The proposed algorithm(D-RLS) derives a QRD RLS algorithm derivation process from RLS algorithm recursively. D-RLS has the similar pattern as the algorithm having the approximation that input signals are separated respectively. Computational complexity of D-RLS is O(N), fewer than $O(N^2)$. To evaluate performance of proposed algorithm, we use the system identification method of FIR and Volterra system. And, finally, we can show D-RLS has an excellent performance.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.18-23
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• 2010

The RLS (Recursive Least Squares) method is a broadly used adaptive algorithm for signal processing in electronic engineering. The RLS algorithm shows a good performance and a fast adaptation within a stationary environment, but it shows a Poor performance within a non-stationary environment because the method has a fixed forgetting factor. In order to enhance 'tracking' performances, BLS methods with an adaptive forgetting factor had been developed. This method shows a good tracking performance, however, it suffers from heavy computational loads. Therefore, we propose a modified AFF-RLS which has relatively low complexity m this paper.

• Annals of Clinical Neurophysiology
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• v.9 no.2
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• pp.75-80
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• 2007

Background: While restless legs syndrome (RLS) is a common disorder, many patients are still remained undiagnosed and clinical data on Asian RLS patients is still limited in amount. Thus, we aimed to describe the clinical spectrum of Korean patients with RLS. Methods: We assessed the clinical characteristics of 77 consecutive RLS patients (43 men, mean age $59.1{\pm}14.9years$; 34 women, mean age $59.3{\pm}14.7years$) followed up by us for at least one and a half years. Results: The mean age at onset of symptoms was $56.4{\pm}14.1$. Two patients (2.6%) developed RLS before the age of 20 years (early-onset RLS). In 44 patients (57.1%), no underlying cause of RLS was found (idiopathic RLS). Family history for RLS was positive only in two (4.5%) of the 44 idiopathic RLS patients. The mean age of patients with idiopathic RLS was $56.8{\pm}13.1$ and that of patients with symptomatic RLS was $60.9{\pm}14.3$. However, there was no statistically significant difference between two groups (p=0.196). All patients complained sensory and motor symptoms in legs, and additional patients (14.3%) also had symptoms in arms. Two significant complications of long-term treatment with dopaminergic agents, namely augmentation and rebound of symptoms, were only reported in two patients. No patient had been diagnosed as RLS before evaluated by us. Conclusions: Our study had some limitations because limited number of patients was enrolled during a fixed period of follow-up in single third referral hospital. However, our findings suggest there are differences in the clinical characteristics of RLS and long-term responses to dopaminergic agents between patients in Korea and western countries.

• Annals of Clinical Neurophysiology
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• v.10 no.2
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• pp.98-100
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• 2008

Restless legs syndrome (RLS) is a sensorimotor neurological disorder in which the primary symptom is a compelling urge to move the legs, accompanied by unpleasant and disturbing sensations in the legs. Although pathophysiologic mechanism of RLS is still unclear, several evidences suggest that RLS is related to dysfunction in central nervous system involving brain and spinal cord. L-DOPA, as the precursor of dopamine, as well as dopamine agonists, plays an essential role in the treatment of RLS leading to the assumption of a key role of dopamine function in the pathophysiology of RLS. Patients with RLS have lower levels of dopamine in the substantia nigra and respond to iron administration. Iron, as a cofactor in dopamine production, plays a central role in the etiology of RLS. Functional neuroimaging studies using PET and SPECT support a central striatal D2 receptor abnormality in the pathophysiology of RLS. Functional MRI suggested a central generator of periodic limb movements during sleep (PLMs) in RLS. However, to date, we have no direct evidence of pathogenic mechanisms of RLS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1141-1145
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• 2016

In general, a variable forgetting factor is applied to the RLS algorithm for the time-varying parameter estimation in the non-stationary environments. The introduction of a variable forgetting factor to RLS needs heavy additional calculation complexity. We propose a new Gauss Newton variable forgetting factor RLS algorithm which needs small amount of calculation as well as estimates the better parameters in time-varying nonstationary environment. The algorithm performs as good as the conventional Gauss Newton variable forgetting factor RLS and the required additional calculation complexity reduces from $O(N^2)$ to O(N).

• Sleep Medicine and Psychophysiology
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• v.22 no.1
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• pp.20-24
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• 2015

Objectives: Restless legs syndrome (RLS) is a common sleep disorder in adults with diabetes. This study investigated the frequency of RLS and clinical correlations in children and adolescents with type 1 diabetes. Methods: This study included 55 consecutive patients (21 males, age $12.6{\pm}3.4years$) with type I diabetes that were regularly treated at the Department of Pediatric Endocrinology. RLS was diagnosed by intensive interviews which also included the Epworth Sleepiness Scale (ESS) and International RLS Rating Scale (IRLSRS). Patients also received neurological examinations and laboratory tests for diabetes, iron metabolism and renal function. Results: Thirteen patients (23.6%, 6 males) were compatible for the diagnostic criteria of RLS. None of the RLS patients showed abnormal findings in neurological evaluations and 7 patients had familial history of RLS. Demographic and laboratory findings were not different between the patients with or without RLS. The RLS group showed significantly increased ESS and IRLSRS scores. Conclusion: RLS was prevalent in children and adolescents with type 1 diabetes. The association between RLS and diabetes-related laboratory findings requires further investigation.

• Korean Journal of Biological Psychiatry
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• v.21 no.3
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• pp.107-113
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• 2014

Objectives Restless legs syndrome (RLS) is a sleep disorder characterized by uncomfortable and unpleasant sensations in the legs and an urge to move the legs, usually at night. The aim of this study is to investigate the incidence of RLS in patients with late life depression and its influence on various clinical outcomes such as severity of depression, sleep quality, cognitive function, and quality of life and accordingly, to elucidate the clinical significance of RLS in patients with late life depression (LLD). Methods This study enlisted 170 depressive patients aged 65 years or older from an outpatient clinic. Structured diagnostic interviews were performed using the Korean version of the Mini-International Neuropsychiatric Interview. All patients completed the questionnaires, including the International RLS Severity Scale, the Korean version of Short-Form 36-Item Health Survey (SF-36), and the Pittsburgh Sleep Quality Index (PSQI). The severity of depression was evaluated by the Korean form of the Geriatric Depression Scale (KGDS) and the level of global cognition was assessed by the Mini-Mental State Examination in the Korean version of The Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (MMSE-KC). Results The incidence of RLS was 17.6% in LLD patients. RLS was more prevalent among the subjects with major depressive disorder (MDD) than those with minor depressive disorder or subsyndromal depressive disorder. The RLS group showed higher score in the KGDS than the Non-RLS group but the difference did not reach the statistical significance (p = 0.095, Student t-test). The mean PSQI score was significantly higher in the RLS group than in the Non-RLS group (p = 0.001, Student t-test). The MMSE-KC score was also lower in the RLS group than in Non-RLS group (p = 0.009, analysis of covariance). But, there was no difference in the score of SF-36 between the RLS group and the Non-RLS group. Conclusions RLS is common in LLD patients, especially in the patients with MDD and is associated with poor sleep quality and cognitive dysfunction, indicating that RLS is clinically significant in patients with LLD. Therefore, RLS should be considered as an important clinical issue in the management of LLD.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.2
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• pp.54-61
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• 2000

This paper presents the performance evaluation of channel estimation algorithm using RLS algorithm lot W-CDMA reverse link over Rayleigh fading channels. By obtaining BER(Bit Error Rate) performance through computer simulations, the RLS(Recursive Least Square) algorithm is compared with the existing WMSA(Weighted Averaging)(K=1,3) and constant gain algorithm. The channel structure, modulation and pilot patterns are applied to the ARIB (Association of Radio Industries and Business) and 3GPP (3rd Generation Partnership Project) ITU-R proposal for the IMT-2000. The BER performance of RLS algorithm with linear interpolation is similar to that of WMSA(K=1) and slightly superior to that of constant gain algorithm at low Doppler frequencies. Also, RLS algorithm performance is better than that of the WMSA(K=1,3) and constant gain algorithms about 4dB at BER=2.0$\times$$10^{-2}$ and Doppler frequencies $F_D$=320Hz. With increasing Doppler frequency, therefore, the BER performance of RLS algorithm with linear interpolation is superior to WMSA(K=L.3) and constant rain algorithms.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.520-525
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• 2009

The conventional studies about an adaptive beamformer assumed that the interference signals are stationary, so they used time-average of signals or Least Mean Squares. However, these methods showed low performance of canceling the non-stationary interferences. In this paper, the MAFF-RLS algorithm is developed in order to cancel non-stationary interferences, and the GSC structure using this algorithm is proposed. Furthermore, the performance of the MAFF-RLS beamformer is verified by simulation using MATLAB. This simulation results show the performance of the proposed beamformer is better than that of the SMI and the conventional RLS beamformer.

• Sleep Medicine and Psychophysiology
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• v.17 no.1
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• pp.5-10
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• 2010

Restless legs syndrome (RLS) is a common sensorimotor disorder that is characterized by an urge to move the legs and peculiar, unpleasant sensations deep in the legs and its prevalence in the general population is between 3.2% and 15%. RLS significantly impairs patients' lives, often by severely disrupting sleep. However, both clinicians and patients under-recognize the RLS. RLS phenotypes include an idiopathic form and secondary form that is usually resulted from various causative conditions. The pathophysiology of RLS may be related with the dopaminergic system, which is closely linked to a number of psychotropic medications, including antidepressant and antipsychotics. Several antidepressants and antipsychotics have been shown to induce or exacerbate RLS. We need pay attention to the fact that commonly prescribed medications can be the cause of RLS.