• Title/Summary/Keyword: LR-test

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Test in Unbalanced Panel Regression Model with Nuisance Parameter (장애모수가 존재하는 불균형 패널회귀모형에서의 검정법)

  • 이재원;정병철;송석헌
    • The Korean Journal of Applied Statistics
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    • v.17 no.3
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    • pp.547-556
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    • 2004
  • This paper consider the testing problem of variance component for the unbalanced two-way error component model with nuisance parameter. We derive the one-sided LM test statistic for testing zero individual(time) effects assuming that the other time-specific(individual) effects are present. Using the Monte Carlo experiments, the computational more demanding LR test slightly underestimates the nominal size and has the low powers relative to LM test statistic.

Further Applications of Johnson's SU-normal Distribution to Various Regression Models

  • Choi, Pilsun;Min, In-Sik
    • Communications for Statistical Applications and Methods
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    • v.15 no.2
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    • pp.161-171
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    • 2008
  • This study discusses Johnson's $S_U$-normal distribution capturing a wide range of non-normality in various regression models. We provide the likelihood inference using Johnson's $S_U$-normal distribution, and propose a likelihood ratio (LR) test for normality. We also apply the $S_U$-normal distribution to the binary and censored regression models. Monte Carlo simulations are used to show that the LR test using the $S_U$-normal distribution can be served as a model specification test for normal error distribution, and that the $S_U$-normal maximum likelihood (ML) estimators tend to yield more reliable marginal effect estimates in the binary and censored model when the error distributions are non-normal.

Antistress effects of Lycii Radicis Cortex in the passive avoidance test and the forced swimming test (지골피(地骨皮)가 스트레스로 인한 기억저하와 우울행동에 미치는 영향)

  • Koh, Dong-Kyun;Lee, Tae-Hee
    • The Korea Journal of Herbology
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    • v.22 no.2
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    • pp.137-146
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    • 2007
  • Objectives : Investigation of the anitstress effects of Lycii Radicis Cortex. Methods : Behavior was measured in PAT and FST after applying stress to rats. Also, TH expression-degree in the regions of VTA and LC was measured, respectively. Results : The memory was improved in the LH 50mg/kg treated group in the passive avoidance test(P<0.01). The duration of immobility in the forced swimming test was significantly decreased in the LR 50mg/kg and 400mg/kg treated groups(P<0.0l). Stress-induced TH increases were meaningfully suppressed in the LR 100mg/kg and 400mg/kg treated group(P<0.001). Conclusion : Lycii Radicis Cortes has the effect of memory improving and antidepressant.

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A Study on Topography Change due to Setup Condition of Artificial Reef (인공리프의 설치조건에 따른 표사이동 특성 연구)

  • Shim, Kyu-Tae;Kim, Kyu-Han
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.3
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    • pp.154-161
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    • 2017
  • The purpose of this study was to investigate the change of length, opening width, and number of openings effecting on topography change around artificial reefs under erosive wave condition. Hydraulic model test was conducted to see sediment transport around the structures and the relation among the installation condition of the artificial reefs, generated velocity, wave deformation, and topographic change was reviewed. Experimental results show that the sediment transport rate was reduced; however, the scour around the structures was increased under the condition of having a single opening compared to the structures having a plurality of openings which shows inversely proportional to the size of Lr/W.

Noisy Speech Enhancement Based on Complex Laplacian Probability Density Function (복소 라플라시안 확률 밀도 함수에 기반한 음성 향상 기법)

  • Park, Yun-Sik;Jo, Q-Haing;Chang, Joon-Hyuk
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.6
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    • pp.111-117
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    • 2007
  • This paper presents a novel approach to speech enhancement based on a complex Laplacian probability density function (pdf). With a use of goodness-of-fit (GOF) test we show that the complex Laplacian pdf is more suitable to describe the conventional Gaussian pdf. The likelihood ratio (LR) is applied to derive the speech absence probability in the speech enhancement algorithm. The performance of the proposed algorithm is evaluated by the objective test and yields better results compared with the conventional Gaussian pdf-based scheme.

Application of artificial neural networks (ANNs) and linear regressions (LR) to predict the deflection of concrete deep beams

  • Mohammadhassani, Mohammad;Nezamabadi-pour, Hossein;Jumaat, Mohd Zamin;Jameel, Mohammed;Arumugam, Arul M.S.
    • Computers and Concrete
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    • v.11 no.3
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    • pp.237-252
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    • 2013
  • This paper presents the application of artificial neural network (ANN) to predict deep beam deflection using experimental data from eight high-strength-self-compacting-concrete (HSSCC) deep beams. The optimized network architecture was ten input parameters, two hidden layers, and one output. The feed forward back propagation neural network of ten and four neurons in first and second hidden layers using TRAINLM training function predicted highly accurate and more precise load-deflection diagrams compared to classical linear regression (LR). The ANN's MSE values are 40 times smaller than the LR's. The test data R value from ANN is 0.9931; thus indicating a high confidence level.

Prediction of shear capacity of channel shear connectors using the ANFIS model

  • Toghroli, Ali;Mohammadhassani, Mohammad;Suhatril, Meldi;Shariati, Mahdi;Ibrahim, Zainah
    • Steel and Composite Structures
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    • v.17 no.5
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    • pp.623-639
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    • 2014
  • Due to recent advancements in the area of Artificial Intelligence (AI) and computational intelligence, the application of these technologies in the construction industry and structural analysis has been made feasible. With the use of the Adaptive-Network-based Fuzzy Inference System (ANFIS) as a modelling tool, this study aims at predicting the shear strength of channel shear connectors in steel concrete composite beam. A total of 1200 experimental data was collected, with the input data being achieved based on the results of the push-out test and the output data being the corresponding shear strength which were recorded at all loading stages. The results derived from the use of ANFIS and the classical linear regressions (LR) were then compared. The outcome shows that the use of ANFIS produces highly accurate, precise and satisfactory results as opposed to the LR.

Isolation of Probiotic Piliated Lactobacillus rhamnosus Strains from Human Fecal Microbiota Using SpaA Antiserum-Based Colony Immunoblotting

  • Yang, Zhen-quan;Xue, Yu;Rao, Sheng-qi;Zhang, Mi;Gao, Lu;Yin, Yong-qi;Chen, Da-wei;Zhou, Xiao-hui;Jiao, Xin-an
    • Journal of Microbiology and Biotechnology
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    • v.27 no.11
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    • pp.1971-1982
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    • 2017
  • Piliated Lactobacillus rhamnosus (pLR) strains possess higher adherent capacity than non-piliated strains. The objective of this study was to isolate and characterize probiotic pLR strains in human fecal samples. To this end, mouse polyclonal antiserum (anti-SpaA) against the recombinant pilus protein (SpaA) of L. rhamnosus strain GG (LGG) was prepared and tested for its reactivity and specificity. With the anti-SpaA, a method combining the de Man, Rogosa, and Sharpe (MRS) agar plating separation and colony immunoblotting (CIB) was developed to isolate pLR from 124 human fecal samples. The genetic and phenotypic characteristics of the resultant pLR isolates were compared by randomly amplified polymorphic DNA (RAPD) fingerprinting, and examination of adhesion to Caco-2 cells, hydrophobicity, autoaggregation, and in vitro gastrointestinal tolerance. Anti-SpaA specifically reacted with three pLR strains of 25 test strains, as assessed by western blotting, immunofluorescence flow cytometry, and immunoelectron microscopy (IEM) assays. The optimized MRS agar separation plus anti-SpaA-based CIB procedure could quantitatively detect $2.5{\times}10^3CFU/ml$ of pLR colonies spiked in $10^6CFU/ml$ of background bacteria. Eight pLR strains were identified in 124 human fecal samples, and were confirmed by 16S RNA gene sequencing and IEM identification. RAPD fingerprinting of the pLR strains revealed seven different patterns, of which only two isolates from infants showed the same RAPD profiles with LGG. Strain PLR06 was obtained with high adhesion and autoaggregation activities, hydrophobicity, and gastrointestinal tolerance. Anti-SpaA-based CIB is a rapid and inexpensive method for the preliminary screening of novel adherent L. rhamnosus strains for commercial purposes.

Improving the Corrosion Resistance of Cold-Rolled Carbon Steel by Treatment with a Hybrid Organic/Inorganic Coating Solution (유/무기 하이브리드 코팅액에 의한 냉간압연강판의 내식특성)

  • Kim, Jung-Ryang;Choi, Chang-Min;Nam, Ki-Woo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.4
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    • pp.405-412
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    • 2012
  • In the past, a very popular way to reduce the corrosion rate of zinc was the use of chemical conversion layers based on $Cr^{+6}$. However, the use of chromium salts is now restricted because of environmental protection legislation. Previous research investigated the optimum corrosion resistance of galvanized steel treated with an organic/inorganic solution containing Si. The result showed that the optimum corrosion resistance occurred by heat treatment of $190^{\circ}C$ in 5 min. In this study, one organic and three hybrid organic/inorganic coating solutions were applied to cold-rolled (CR) carbon steel. The coatings were then evaluated for corrosion resistance under a salt spray test. The coating solutions examined in this study consisted of urethane-only, urethane-Si, urethane-Si-Ti, and urethane-Si-Ti-epoxy. The results of the 7 h salt spray test showed that the urethane-Si-Ti and urethane-Si-Ti-epoxy coating solutions had superior corrosion resistance on CR steel.