• Title/Summary/Keyword: Nonlinear least square

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Study on the Development of Multi-Agents Position Tracking System Using Ultrasonic Transducers (초음파 센서를 이용한 다수의 이동형 개체 위치 추적시스템 개발에 관한 연구)

  • Choe, Jin-Hee;Choy, Ick;Cho, Whang
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.5
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    • pp.725-731
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    • 2013
  • In This paper, through simulation, proposes a system which makes it possible for freely moving multiple agents with ultrasonic receivers to estimate their own position by themselves using the ultrasonic signals sequentially emitted from multiple ultrasonic transmitters. This system possesses an advantage that there is no limit in the number of agents existing in the space covered by more than three transmitters fixed at proper locations. Hence, the proposed system can be utilized effectively in position tracking control of multiple robotic agents system and motion capturing system.

A comparison study on regression with stationary nonparametric autoregressive errors (정상 비모수 자기상관 오차항을 갖는 회귀분석에 대한 비교 연구)

  • Yu, Kyusang
    • The Korean Journal of Applied Statistics
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    • v.29 no.1
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    • pp.157-169
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    • 2016
  • We compare four methods to estimate a regression coefficient under linear regression models with serially correlated errors. We assume that regression errors are generated with nonlinear autoregressive models. The four methods are: ordinary least square estimator, general least square estimator, parametric regression error correction method, and nonparametric regression error correction method. We also discuss some properties of nonlinear autoregressive models by presenting numerical studies with typical examples. Our numerical study suggests that no method dominates; however, the nonparametric regression error correction method works quite well.

Clinical Pharmacokinetics of Gentamicin in Gastrointestinal Surgical Patients (위장관 수술환자에서 겐타마이신의 임상약물동태)

  • Choi, Jun-Shik;Moon, Hong-Seog;Choi, In;Burm, Jin-Pil
    • YAKHAK HOEJI
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    • v.40 no.1
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    • pp.1-9
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    • 1996
  • The purpose of this investigation was to determine pharmacokinetic parameters of gentamicin using nonlinear least square regression(NLSR) and Bayesian analysis in Korean normal volunteers and gastrointestinal surgical patients. Nonparametric expected maximum(NPEM) method for population pharmacokinetic parameters was used. Gentamicin was administered every 8 hours for 3 days by infusion over 30 minutes. The volume of distribution(V) and elimination rate constant(K) of gentamicin were $0.226{\pm}0.032,\;0.231{\pm}0.063L/Kg\;and\;0.357{\pm}0.024,\;0.337{\pm}0.041hr^{-1}$ for normal volunteers and gastrointestinal surgical patients using NLSR analysis. Population pharmacokinetic parameters, KS and VS were $0.00344{\pm}0.00049(hr{\cdot}ml/min/1.73m^2)^{-1}\;and\;0.214{\pm}0.0502L/Kg$ for gastrointestinal surgical patients using NPEM method. The V and K were $0.216{\pm}0.048L/Kg\;and\;0.336{\pm}0.043hr^{-1}$ for gastrointestinal surgical patients using Bayesian analysis. There were no differences in gentamicin pharmacokinetics between NLSR and Bayesian analysis in gastrointestinal surgical patient.

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Enhancement of Source Localization Performance using PMP Method in a Multipath Environment (다중경로 환경에서 PMP기법을 이용한 음원의 위치 추정성능 향상)

  • Lee, Ho Jin;Yoon, Kyung Sik;Shin, Dong Hoon;Lee, Kyun Kyung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.2
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    • pp.182-188
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    • 2014
  • Source localization is an important problem in the field of sonar and radar, etc. For the purpose of source localization, two or more spatially separated sensors are often used to measure the time difference of arrivals of a radiating source whose transmitted signal waveform is unknown. The NLS(Nonlinear Least Square) cost function with curve fitting method was proposed recently, which provide robust source localization performance by reducing estimation ambiguity. However, even this algorithm shows degraded performance in a multipath environment. To estimates source localization correctly, source localization algorithm that eliminate the effect of multipath signals is required. In this paper, PMP(Power Matching Procedure) is added to the algorithm, which provides improved source localization performance by properly cutting out the effect of multipath signals. Through simulation the performance of the proposed source localization algorithm is verified.

Long-term Creep Strain-Time Curve Modeling of Alloy 617 for a VHTR Intermediate Heat Exchanger (초고온가스로 중간 열교환기용 Alloy 617의 장시간 크리프 변형률-시간 곡선 모델링)

  • Kim, Woo-Gon;Yin, Song-Nam;Kim, Yong-Wan
    • Korean Journal of Metals and Materials
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    • v.47 no.10
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    • pp.613-620
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    • 2009
  • The Kachanov-Rabotnov (K-R) creep model was proposed to accurately model the long-term creep curves above $10^5$ hours of Alloy 617. To this end, a series of creep data was obtained from creep tests conducted under different stress levels at $950^{\circ}C$. Using these data, the creep constants used in the K-R model and the modified K-R model were determined by a nonlinear least square fitting (NLSF) method, respectively. The K-R model yielded poor correspondence with the experimental curves, but the modified K-R model provided good agreement with the curves. Log-log plots of ${\varepsilon}^{\ast}$-stress and ${\varepsilon}^{\ast}$-time to rupture showed good linear relationships. Constants in the modified K-R model were obtained as ${\lambda}$=2.78, and $k=1.24$, and they showed behavior close to stress independency. Using these constants, long-term creep curves above $10^5$ hours obtained from short-term creep data can be modeled by implementing the modified K-R model.

The Nonlinear Analysis and Modeling of the ER Fluid Damper Using Higher Order Spectrum (고차 주파수 스펙트럼을 이용한 ER 유체 댐퍼의 비선형 특성 해석 및 모델링 연구)

  • Kim, Dong-Hyun;Joung, Tae-Whee;Joh, Joongseon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.1 s.178
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    • pp.105-112
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    • 2006
  • The nonlinear damping force model is made to identify the properties of the ER (electro-rheological) fluid suspension damper. The instrumentation is carried out to measure the damping force of the ER damper. The higher order spectral analysis method is used to investigate the nonlinear frequency coupling phenomena with the damping force signal according to the sinusoidal excitation of the damper. The distinctive higher order nonlinear characteristics are observed. The nonlinear damping force model, which has the higher order velocity terms, is proposed with the result of higher order spectrum analysis. The higher order terms coefficients, which vary according to the strength of the electric field, are calculated using the least square method.

Nonlinear Characteristics of Fuzzy Scatter Partition-Based Fuzzy Inference System

  • Park, Keon-Jun;Huang, Wei;Yu, C.;Kim, Yong K.
    • International journal of advanced smart convergence
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    • v.2 no.1
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    • pp.12-17
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    • 2013
  • This paper introduces the fuzzy scatter partition-based fuzzy inference system to construct the model for nonlinear process to analyze nonlinear characteristics. The fuzzy rules of fuzzy inference systems are generated by partitioning the input space in the scatter form using Fuzzy C-Means (FCM) clustering algorithm. The premise parameters of the rules are determined by membership matrix by means of FCM clustering algorithm. The consequence part of the rules is represented in the form of polynomial functions and the parameters of the consequence part are estimated by least square errors. The proposed model is evaluated with the performance using the data widely used in nonlinear process. Finally, this paper shows that the proposed model has the good result for high-dimension nonlinear process.

A Study on Adaptive Interference Cancellation System of RF Repeater Using the Grouped Constant-Modulus Algorithm (그룹화 CMA 알고리즘을 이용한 RF 중계기의 적응 간섭 제거 시스템(Adaptive Interference Cancellation System)에 관한 연구)

  • Han, Yong-Sik;Yang, Woon-Geun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.9
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    • pp.1058-1064
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    • 2008
  • In this paper, we proposed a new hybrid interference canceller using the adaptive filter with Grouped CMA(Constant Modulus Algorithm)-LMS(Least Mean Square) algorithm in the RF(Radio Frequency) repeater. The feedback signal generated from transmitter antenna to receiver antenna reduces the performance of the receiver system. The proposed interference canceller has better channel adaptive performance and a lower MSE(Mean Square Error) than conventional structure because it uses the cancellation method of Grouped CMA algorithm. This structure reduces the number of iterations fur the same MSE performance and hardware complexity compared to conventional nonlinear interference canceller. Namely, MSE values of the proposed algorithm were lower than those of LMS algorithm by 2.5 dB and 4 dB according to step sizes. And the proposed algorithm showed fast speed of convergence and similar MSE performance compared to VSS(Variable Step Size)-LMS algorithm.

Sustained Vowel Modeling using Nonlinear Autoregressive Method based on Least Squares-Support Vector Regression (최소 제곱 서포트 벡터 회귀 기반 비선형 자귀회귀 방법을 이용한 지속 모음 모델링)

  • Jang, Seung-Jin;Kim, Hyo-Min;Park, Young-Choel;Choi, Hong-Shik;Yoon, Young-Ro
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.7
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    • pp.957-963
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    • 2007
  • In this paper, Nonlinear Autoregressive (NAR) method based on Least Square-Support Vector Regression (LS-SVR) is introduced and tested for nonlinear sustained vowel modeling. In the database of total 43 sustained vowel of Benign Vocal Fold Lesions having aperiodic waveform, this nonlinear synthesizer near perfectly reproduced chaotic sustained vowels, and also conserved the naturalness of sound such as jitter, compared to Linear Predictive Coding does not keep these naturalness. However, the results of some phonation are quite different from the original sounds. These results are assumed that single-band model can not afford to control and decompose the high frequency components. Therefore multi-band model with wavelet filterbank is adopted for substituting single band model. As a results, multi-band model results in improved stability. Finally, nonlinear sustained vowel modeling using NAR based on LS-SVR can successfully reconstruct synthesized sounds nearly similar to original voiced sounds.

Performance Comparison of Acoustic Equalizers using Adaptive Algorithms in Shallow Water Condition (천해환경에서 적응 알고리즘을 이용한 음향 등화기의 성능 비교)

  • Chuai, Ming;Park, Kyu-Chil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.2
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    • pp.253-260
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    • 2018
  • The acoustic communication channel in shallow underwater is typically shown as time-varying multipath fading channel characteristics. The received signal through channel transmission cause inter-symbol interference (ISI) owing to multiple components of different time delay and amplitude. To compensate for this, several techniques have been used, and one of them is acoustic equalizer. In this study, we used four equalizers - feed forward equalizer (FFE), decision directed equalizer (DDE), decision feedback equalizer (DFE) and combination DDE with DFE to compensate ISI. And we applied two adaptive algorithms to adjust coefficient of equalizers - normalized least mean square algorithm and recursive least square algorithm. As result, we found that it has a significant performance improvement over 6 dB on SNR in nonlinear equalizer. By combination of DFE and DDE has almost best performance in any case.