• Title/Summary/Keyword: Likelihood measure

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Dual-Channel Acoustic Event Detection in Multisource Environments Using Nonnegative Tensor Factorization and Hidden Markov Model (비음수 텐서 분해 및 은닉 마코프 모델을 이용한 다음향 환경에서의 이중 채널 음향 사건 검출)

  • Jeon, Kwang Myung;Kim, Hong Kook
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.1
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    • pp.121-128
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    • 2017
  • In this paper, we propose a dual-channel acoustic event detection (AED) method using nonnegative tensor factorization (NTF) and hidden Markov model (HMM) in order to improve detection accuracy of AED in multisource environments. The proposed method first detects multiple acoustic events by utilizing channel gains obtained from the NTF technique applied to dual-channel input signals. After that, an HMM-based likelihood ratio test is carried out to verify the detected events by using channel gains. The detection accuracy of the proposed method is measured by F-measures under 9 different multisource conditions. Then, it is also compared with those of conventional AED methods such as Gaussian mixture model and nonnegative matrix factorization. It is shown from the experiments that the proposed method outperforms the convectional methods under all the multisource conditions.

Identifying Copy Number Variants under Selection in Geographically Structured Populations Based on F-statistics

  • Song, Hae-Hiang;Hu, Hae-Jin;Seok, In-Hae;Chung, Yeun-Jun
    • Genomics & Informatics
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    • v.10 no.2
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    • pp.81-87
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    • 2012
  • Large-scale copy number variants (CNVs) in the human provide the raw material for delineating population differences, as natural selection may have affected at least some of the CNVs thus far discovered. Although the examination of relatively large numbers of specific ethnic groups has recently started in regard to inter-ethnic group differences in CNVs, identifying and understanding particular instances of natural selection have not been performed. The traditional $F_{ST}$ measure, obtained from differences in allele frequencies between populations, has been used to identify CNVs loci subject to geographically varying selection. Here, we review advances and the application of multinomial-Dirichlet likelihood methods of inference for identifying genome regions that have been subject to natural selection with the $F_{ST}$ estimates. The contents of presentation are not new; however, this review clarifies how the application of the methods to CNV data, which remains largely unexplored, is possible. A hierarchical Bayesian method, which is implemented via Markov Chain Monte Carlo, estimates locus-specific $F_{ST}$ and can identify outlying CNVs loci with large values of FST. By applying this Bayesian method to the publicly available CNV data, we identified the CNV loci that show signals of natural selection, which may elucidate the genetic basis of human disease and diversity.

Estimating the Economic Value of the Songieong Beach Using A Count Data Model: - Off-season Estimating Value of the Beach - (가산자료모형을 이용한 송정 해수욕장의 경제적 가치추정: - 비수기 해수욕장의 가치추정 -)

  • Heo, Yun-Jeong;Lee, Seung-Lae
    • The Journal of Fisheries Business Administration
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    • v.38 no.2
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    • pp.79-101
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    • 2007
  • The purpose of this study is to estimate the economic value of the Songieong Beach in Off-season, using a Individual Travel Cost Model(ITCM). Songieong Beach is located in Busan but far away from city. These days, however, the increased rate of traffic inflow to the Songieong beach and the five-day working week are reflected in the trend analysis. Moreover, people have changed psychological value. For that reason, visitors are on the increase on the beach in off-season. The ITCM is applied to estimate non-market value or environmental Good like a Contingent Valuation Method and Hedonic Price Model etc. The ITCM was derived from the Count Data Model(i.e. Poisson and Negative Binomial model). So this paper compares Poisson and negative binomial count data models to measure the tourism demands. The data for the study were collected from the Songjeong Beach on visitors over the a week from November 1 through November 23, 2006. Interviewers were instructed to interview only individuals. So the sample was taken in 113. A dependent variable that is defined on the non-negative integers and subject to sampling truncation is the result of a truncated count data process. This paper analyzes the effects of determinants on visitors' demand for exhibition using a class of maximum-likelihood regression estimators for count data from truncated samples, The count data and truncated models are used primarily to explain non-negative integer and truncation properties of tourist trips as suggested by the economic valuation literature. The results suggest that the truncated negative binomial model is improved overdispersion problem and more preferred than the other models in the study. This paper is not the same as the others. One thing is that Estimating Value of the Beach in off-season. The other thing is this study emphasizes in particular 'travel cost' that is not only monetary cost but also including opportunity cost of 'travel time'. According to the truncated negative binomial model, estimates the Consumer Surplus(CS) values per trip of about 199,754 Korean won and the total economic value was estimated to be 1,288,680 Korean won.

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Evaluation of the Fatigue Life for Carbon/Epoxy Composite Material by the Residual Strength Degradation Analysis (탄소섬유/에폭시 복합재료의 잔류강도 저하해석에 의한 피로수명 평가)

  • 심봉식;성낙원;옹장우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.1908-1918
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    • 1991
  • Fatigue tests have been carried out to measure the degradation of the residual strength and the fatigue life in carbon/epoxy (0/45/90/-45)$_{2s}$ composite materials. Theoretical predictions of residual strength and fatigue life were compared with experimental results. Distribution characteristics were studied using the probability of failure based on the cumulative distribution function and median rand. The static ultimate strength of carbon/epoxy composites used herein is observed to be relatively higher than that of existing similar composites ; while fatigue life is shorter due to the brittleness of matrix. The fatigue life obtained in these experiments is shorter than that estimated by residual strength degradation model when the stress level above 0.6 For the stress level of 0.6, the experimental value was abruptly increased. The cumulative distribution function for the static ultimate strength is well correlated to that for the strength converted from the measured fatigue life. Also, the predicted distribution of residual strength shows good agreement with the experimental results. Therefore, it is proven that the residual strength degradation model is reasonable.e.

Impacts of Information Source and E-service Quality on Mobile Shopping Behavior in KakaoTalk

  • Yi, Kyong-Hwa;Jeon, Sua;Kim, HaeJung Maria;Forney, Judith
    • Journal of Fashion Business
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    • v.20 no.6
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    • pp.32-51
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    • 2016
  • KakaoTalk has become a reputed mobile social network and an inseparable part of people's lives by leading the mobile industry in South Korea. However, there is a lack of studies in academia regarding perception of the consumers and assessment toward the mobile marketing and services by KakaoTalk. Based on the theoretical orientation of Elaboration Likelihood Model (ELM: Petty & Cacioppo, 1986) and electronic service quality (E-S-QUAL: Parasuraman, Zeithaml, & Malhotra, 2005), this study investigates the effects of information sources (Charles & Richard, 1988), and examines the consumer perception toward the service quality of KakaoTalk. A total of 209 responses were collected, using a self-administered survey in Seoul and Gyeonggi province, South Korea from March 2015 to June 2015. A seven-point Likert scale survey was developed to measure the information sources (i.e., argument quality, post popularity, and post attractiveness), electronic service quality (i.e., efficiency, fulfillment, privacy, and system availability), attitude (i.e., usefulness, preference, and overall attitude), and behavioral intention (i.e., like intention, share intention, and purchase intention). This study reveals a consensus that an online environment is different from the traditional retail context in terms of information source and service quality. Specifically, the results indicate that argument quality greatly impacts the attitudes of the individuals and their behavioral intention toward mobile shopping via social media channel. The most powerful factor among E-S-QUAL is "efficiency." This dimension of service quality influences the customer perception of usefulness and preference as well as share and like intention toward mobile shopping on KakaoTalk.

ROC Curve Fitting with Normal Mixtures (정규혼합분포를 이용한 ROC 분석)

  • Hong, Chong-Sun;Lee, Won-Yong
    • The Korean Journal of Applied Statistics
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    • v.24 no.2
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    • pp.269-278
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    • 2011
  • There are many researches that have considered the distribution functions and appropriate covariates corresponding to the scores in order to improve the accuracy of a diagnostic test, including the ROC curve that is represented with the relations of the sensitivity and the specificity. The ROC analysis was used by the regression model including some covariates under the assumptions that its distribution function is known or estimable. In this work, we consider a general situation that both the distribution function and the elects of covariates are unknown. For the ROC analysis, the mixtures of normal distributions are used to estimate the distribution function fitted to the credit evaluation data that is consisted of the score random variable and two sub-populations of parameters. The AUC measure is explored to compare with the nonparametric and empirical ROC curve. We conclude that the method using normal mixtures is fitted to the classical one better than other methods.

The Effect of the Pedicle-Facet Angle on Degenerative Cervical Spondylolisthesis

  • Kim, Hyung Cheol;Jun, Hyo Sub;Kim, Ji Hee;Chang, In Bok;Song, Joon Ho;Oh, Jae Keun
    • Journal of Korean Neurosurgical Society
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    • v.58 no.4
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    • pp.341-345
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    • 2015
  • Objective : To measure the orientation of the facet joints of cervical spine (C-spine) segments in the sagittal plane, known as the pedicle-facet (P-F) angle, and to use these measurements to evaluate the relationship between the P-F angle and the amount of vertebral anterolisthesis in patients with degenerative cervical spondylolisthesis (DCS). Methods : A retrospective case-control study was performed including 30 age- and sex-matched patients with DCS and 30 control participants. Anterior-posterior and lateral view radiographs of the C-spine were obtained in a standing position. The P-F angle at all cervical levels and the amount of anterolisthesis at C4-5 were measured from lateral view plain radiographs. Results : The P-F angles at C4-5 were $141.14{\pm}7.14^{\circ}$ for the DCS group and $130.53{\pm}13.50^{\circ}$ (p=0.012) for the control group, and at C5-6 were $137.46{\pm}8.53^{\circ}$ for the DCS group and $128.53{\pm}16.01^{\circ}$ for the control group (p=0.001). The mean P-F angle at C4-5 did not correlate with the amount of anterolisthesis (p=0.483). The amount of anterior slippage did correlate with age (p<0.001). Conclusion : The P-F angle was intrinsically higher at C4-5, compared to C5-6, in both the DCS and control groups, which might explain the increased likelihood for anterolisthesis of C4. Higher P-F angles in the DCS group may be a predisposing factor to slippage. The P-F angle may interact with age to increase incidence of anterolisthesis with increasing age.

Impact of Ordinal Rank on Career Choice (상대 순위가 진로 결정에 미치는 영향)

  • Lim, Seulgi;Lee, Soohyung
    • Journal of Labour Economics
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    • v.40 no.2
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    • pp.1-29
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    • 2017
  • We examine the extent to which students' performance relative to peers affects their career choice. Specifically, we analyze the relationship between a student's mathematics ranking in his/her school and the likelihood of choosing Mathematics and Science track in high school. Using a panel dataset of students in Seoul, we measure a student's performance using two variables: absolute performance and relative performance. The former measures a student's performance relative to the entire sample, while the latter measures performance relative to the student's peers in the same school. After controlling for test scores and other characteristics, we find that the students with a poor relative ranking are 11 percentage points less likely to choose the Mathematics and Science track. Relative performance affects girls more greatly than boys. Although relative performance affects a student's self-efficacy and class participation, our accounting exercise suggests that this channel accounts for only 12 percent of the impact, implying that students may respond to the relative ranking mostly due to other factors, such as strategic consideration to perform well in college applications.

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The Comparative Study for Software Reliability Models Based on NHPP (NHPP에 기초한 소프트웨어 신뢰도 모형에 대한 비교연구)

  • Gan, Gwang-Hyeon;Kim, Hui-Cheol;Lee, Byeong-Su
    • The KIPS Transactions:PartD
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    • v.8D no.4
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    • pp.393-400
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    • 2001
  • This paper presents a stochastic model for the software failure phenomenon based on a nonhomogeneous Poisson process (NHPP). The failure process is analyzed to develop a suitable mean value function for the NHPP ; expressions are given for several performance measure. Actual software failure data are compared with generalized model by Goel dependent on the constant reflecting the quality of testing. The performance measures and parametric inferences of the new models, Rayleigh and Gumbel distributions, are discussed. The results of the new models are applied to real software failure data and compared with Goel-Okumoto and Yamada, Ohba and Osaki models. Tools of parameter inference was used method of the maximun likelihood estimate and the bisection algorithm for the computing nonlinear root. In this paper, using the sum of the squared errors, model selection was employed. The numerical example by NTDS data was illustrated.

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Order restricted inference for testing the investors' attention effect on stock returns (주식 수익률에 미치는 투자자들의 관심효과를 검정하기 위한 순서제약추론)

  • Kim, Youngrae;Lim, Johan;Lee, Sungim;Choi, Sujung
    • The Korean Journal of Applied Statistics
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    • v.31 no.3
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    • pp.409-416
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    • 2018
  • Significant research has been conducted in the financial sector on the behavior of investors in the stock market. In this paper, we directly measure the degree of interest using the ranking of the frequency mentioned in the stock message board operated by Daum Communications Corp. and test the fact that the higher ranking of the frequency results in the higher stock returns in order to investigate the attention effect on the stock returns in the Korean stock market. We also propose and apply the likelihood ratio test procedure for order restricted hypotheses in order to test the attention effect. The test results shows that the higher rank in the frequency mentioned in the message board is related to stock returns (p-value < $10^{-6}$). Therefore, we conclude that an investors' attention effects exist in the Korean stock market.