• Title/Summary/Keyword: Maximum Likelihood.

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A Study on the Intercity Mode Choice Behavior of Daegu Citizens According to the Introduction of Gyeongbu High-Speed Railway (경부 고속철도 개통에 따른 대구시민의 지역 간 통행수단 선택행태 분석에 관한 연구)

  • Yun, Dae-Sik;Yuk, Tae-Suk;Kim, Sang-Hwang
    • Journal of Korean Society of Transportation
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    • v.24 no.1 s.87
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    • pp.29-38
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    • 2006
  • After the first opening of the KTX in April 2004, travel time between major cities has been dramatically reduced. The reduction rates range from 32% to 47%. Considering travel time reduction between major cities, this study concerned about the intercity travel impact of the KTX operation. This study aimed to analyze intercity mode choice behavior of Daegu Citizens according to the first opening of the KTX. This study takes place in two sections. These are (i) the section of KTX between Daegu and Seoul, and (ii) the section of KTX between Daegu and Daejeon. This study estimated empirical models for analyzing intercity mode choice behavior according to the first opening of the KTX. This study makes use of the data from travel survey from Daegu metropolitan area. The main part of the survey was carried out in the KTX Dong-Daegu station. The survey data includes the information on travel from Daegu to Daejeon and from Daegu to Seoul. In order to analyze intercity choice behavior according to the frist opening of the KTX, multinomial model structure is used. For the model specification, a variety of behavioral assumptions about the factors which affect the mode choice, were considered. From the empirical model estimation, it is found that OVTT(Out-of-Vehicle Travel Time), OVTC(Out-of-Vehicle Travel Cost), IVTT(In-Vehicle Travel Time), IVTC(In-Vehicle Travel Cost), travel frequency, travel purpose, sex, age, occupation. household income, individual income are significant in choosing intercity travel mode. However, it is found that the intercity nde choice behavior is different between (i) the section of KTX between Daegu and Seoul, and (ii) the section of KTX between Daegu and Daejeon. Furthermore, some policy implications are discussed in conclusion.

Relationship between Brand Personality and the Personality of Consumers, and its Application to Corporate Branding Strategy

  • Kim, Young-Ei;Lee, Jung-Wan;Lee, Yong-Ki
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.3
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    • pp.27-57
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    • 2008
  • Many consumers enjoy the challenge of purchasing a brand that matches well with their own values and personalities (for example, Ko et al., 2008; Ko et al., 2006). Therefore, the personalities of consumers can impact on the final selection of a brand and its brand personality in two ways: first, the consumers may incline to purchase a brand or a product that reflects their own personalities; second, consumers tend to choose a company that has similar brand personalities to those brands that are being promoted. Therefore, the objectives of this study are following: 1. Is there any empirical relationship between a consumer's personality and the personality of a brand that he or she chooses? 2. Can a corporate brand be differentiated by the brand personality? In short, consumers are more likely to hold favorable attitudes towards those brands that match their own personality and will most probably purchase those brands matching well with their personality. For example, Matzler et al. (2006) found that extraversion and openness were positively related to hedonic product value; and that the personality traits directly (openness) and indirectly (extraversion, via hedonic value) influenced brand effects, which in turn droved attitudinal and purchase loyalty. Based on the above discussion, the following hypotheses are proposed: Hypothesis 1: the personality of a consumer is related to the brand personality of a product/corporate that he/she purchases. Kuksov (2007) and Wernerfelt (1990) argued that brands as a symbolic language allowed consumers to communicate their types to each other and postulated that consumers had a certain value of communicating their types to each other. Therefore, how brand meanings are established, and how a firm communicate with consumers about the meanings of the brand are interesting topics for research (for example, Escalas and Bettman, 2005; McCracken, 1989; Moon, 2007). Hence, the following hypothesis is proposed: Hypothesis 2: A corporate brand identity is differentiated by the brand personality. And there are significant differences among companies. A questionnaire was developed for collecting empirical measures of the Big-Five personality traits and brand personality variables. A survey was conducted to the online access panel members through the Internet during December 2007 in Korea. In total, 500 respondents completed the questionnaire, and considered as useable. Personality constructs were measured using the Five-factor Inventory (NEO-FFI) scale and a total of 30 items were actually utilized. Brand personality was measured using the five-dimension scale developed by Aaker (1997). A total of 17 items were actually utilized. The seven-point Likert-type scale was the format of responses, for example, from 1 indicating strongly disagreed to 7 for strongly agreed. The Analysis of Moment Structures (AMOS) was used for an empirical testing of the model, and the Maximum Likelihood Estimation (MLE) was applied to estimate numerical values for the components in the model. To diagnose the presence of distribution problems in the data and to gauge their effects on the parameter estimates, bootstapping method was used. The results of the hypothesis-1 test empirically show that there exit certain causality relationship between a consumer's personality and the brand personality of the consumer's choice. Thus, the consumer's personality has an impact on consumer's final selection of a brand that has a brand personality matches well with their own personalities. In other words, the consumers are inclined to purchase a brand that reflects their own personalities and tend to choose a company that has similar brand personalities to those of the brand being promoted. The results of this study further suggest that certain dimensions of the brand personality cause consumers to have preference to certain (corporate) brands. For example, the conscientiousness, neuroticism, and extraversion of the consumer personality have positively related to a selection of "ruggedness" characteristics of the brand personality. Consumers who possess that personality dimension seek for matching with certain brand personality dimensions. Results of the hypothesis-2 test show that the average "ruggedness" attributes of the brand personality differ significantly among Korean automobile manufacturers. However, the result of ANOVA also indicates that there are no significant differences in the mean values among manufacturers for the "sophistication," "excitement," "competence" and "sincerity" attributes of the corporate brand personality. The tight link between what a firm is and its corporate brand means that there is far less room for marketing communications than there is with products and brands. Consequently, successful corporate brand strategies must position the organization within the boundaries of what is acceptable, while at the same time differentiating the organization from its competitors.

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The Measurement and Comparison of the Relative Efficiency for Currency Futures Markets : Advanced Currency versus Emerging Currency (통화선물시장의 상대적 효율성 측정과 비교 : 선진통화 대 신흥통화)

  • Kim, Tae-Hyuk;Eom, Cheol-Jun;Kang, Seok-Kyu
    • The Korean Journal of Financial Management
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    • v.25 no.1
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    • pp.1-22
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    • 2008
  • This study is to evaluate, to the extent to, which advanced currency futures and emerging currency futures markets can predict accurately the future spot rate. To this end, Johansen's the maximum-likelihood cointegration method(1988, 1991) is adopted to test the unbiasedness and efficiency hypothesis. Also, this study is to estimate and compare a quantitative measure of relative efficiency as a ratio of the forecast error variance from the best-fitting quasi-error correction model to the forecast error variance of the futures price as predictor of the spot price in advanced currency futures with in emerging currency futures market. Advanced currency futures is British pound and Japan yen. Emerging currency futures includes Korea won, Mexico peso, and Brazil real. The empirical results are summarized as follows : First, the unbiasedness hypothesis is not rejected for Korea won and Japan yen futures exchange rates. This indicates that the emerging currency Korea won and the advanced currency Japan yen futures exchange rates are likely to predict accurately realized spot exchange rate at a maturity date without the trader having to pay a risk premium for the privilege of trading the contract. Second, in emerging currency futures markets, the unbiasedness hypothesis is not rejected for Korea won futures market apart from Mexico peso and Brazil real futures markets. This indicates that in emerging currency futures markets, Korea won futures market is more efficient than Mexico peso and Brazil real futures markets and is likely to predict accurately realized spot exchange rate at a maturity date without risk premium. Third, this findings show that the results of unbiasedness hypothesis tests can provide conflicting finding. according to currency futures class and forecasts horizon period, Fourth, from the best-fitting quasi-error correction model with forecast horizons of 14 days, the findings suggest the Japan yen futures market is 27.06% efficient, the British pound futures market is 26.87% efficient, the Korea won futures market is 20.77% efficient, the Mexico peso futures market is 11.55%, and the Brazil real futures market is 4.45% efficient in the usual order. This indicates that the Korea won-dollar futures market is more efficient than Mexico peso, and Brazil real futures market. It is therefore possible to concludes that the Korea won-dollar currency futures market has relatively high efficiency comparing with Mexico peso and Brazil real futures markets of emerging currency futures markets.

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Estimation of Genetic Parameters for Economic Traits in Yorkshire (요크셔종에 대한 경제형질의 유전모수 추정)

  • Song, K.L.;Kim, B.W.;Kim, S.D.;Choi, C.S.;Kim, M.J.;Lee, J.G.
    • Journal of Animal Science and Technology
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    • v.44 no.5
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    • pp.499-506
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    • 2002
  • This study was conducted to estimate the heritabilities and genetic and phenotypic correlations among average daily gain, age at 90kg and backfat thickness in Yorkshire pigs. The data were obtained from 2,111 heads of Yorkshire tested at National Livestock Research Institute from May, 1994 to April, 2000. Genetic parameters were estimated with a multiple trait animal model by using DF-REML (Deri- vative-Free REstricted Maximum Likelihood). The results obtained are summarized as follows ; The means of traits studied were 0.871${\pm}$0.124 kg for average daily gain, 145.397${\pm}$11.718 days for age at 90kg and 1.476${\pm}$0.241 cm for backfat thickness. The estimated heritabilities were 0.55 for average daily gain, 0.56 for age at 90kg and 0.55 for backfat thickness. The genetic correlation of average daily gain with age at 90kg and backfat thickness were -0.82, 0.10, respectively. The genetic correlation of age at 90kg with backfat thickness was -0.25. The phenotypic correlations of average daily gain(ADG) with age at 90kg and backfat thickness and age at 90kg with backfat thickness were -0.77, 0.02 and -0.05 respectively. Though phenotypic correlation of ADG and age at 90kg was low, breeding project should be carefully considered by high genetic correlation. High heritabilities on all economic traits were obtained. Therefore, it is considered that suitable selection and management is needed successful improvement.

Estimation of Genetic Parameters for Ultrasound and Carcass Traits in Hanwoo (한우의 초음파 측정 형질과 도체 형질의 유전모수 추정)

  • Kim, Hyeong-Cheol;Lee, Seung-Hwan;Dang, Chang-Gwon;Jeon, Gi-Jun;Yeon, Seong-Heum;Cho, Young-Moo;Lee, Sang-Min;Yang, Boh-Suk;Kim, Jong-Bok
    • Journal of Animal Science and Technology
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    • v.54 no.5
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    • pp.331-336
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    • 2012
  • This study was conducted to estimate genetic parameters for ultrasound and carcass traits in Hanwoo. Heritabilities and genetic and phenotypic correlations were estimated for carcass and ultrasound measurements collected from Hanwoo cows (n=312) born at Hanwoo experiment station. Traits evaluated were eye muscle area (EMA), backfat thickness (BF), marbling score (MS) from carcass, and ultrasound eye muscle area (UEMA), ultrasound backfat (UBF), and ultrasound marbling score (UMS). Parameters were estimated using multi-trait animal models byderivative-free restricted maximum likelihood procedures. Estimated heritabilities for UBF, UEMA and UMS were 0.43, 0.23 and 0.32, while heritabilities for BF, EMA and MS were 0.33, 0.13 and 0.33 in fattened cows, respectively. Genetic correlations between ultrasound and carcass measurements were estimated to -0.19, -0.61, and -0.36 for UBF: UEMA, UBF: UMS, and UEMA: UMS in fattened cows, respectively. Phenotypic correlations between ultrasound and carcass measurements were 0.03, 0.13 and 0.26 for UBF: UEMA, UBF: UMS, and UEMA: UMS in fattened cows, respectively. As for the steer, genetic correlations between ultrasound and carcass measurements were 0.36, -0.80 and 0.27 for UBF: UEMA, UBF: UMS, and UEMA: UMS in steers, respectively. Phenotypic correlations between ultrasound and carcass measurements were 0.13, 0.07 and 0.41 for UBF: UEMA, UBF: UMS, and UEMA: UMS in steers, respectively. In conclusion, this finding would be very useful to implement into Hanwoo breeding program.

A Control Method for designing Object Interactions in 3D Game (3차원 게임에서 객체들의 상호 작용을 디자인하기 위한 제어 기법)

  • 김기현;김상욱
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.3
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    • pp.322-331
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    • 2003
  • As the complexity of a 3D game is increased by various factors of the game scenario, it has a problem for controlling the interrelation of the game objects. Therefore, a game system has a necessity of the coordination of the responses of the game objects. Also, it is necessary to control the behaviors of animations of the game objects in terms of the game scenario. To produce realistic game simulations, a system has to include a structure for designing the interactions among the game objects. This paper presents a method that designs the dynamic control mechanism for the interaction of the game objects in the game scenario. For the method, we suggest a game agent system as a framework that is based on intelligent agents who can make decisions using specific rules. Game agent systems are used in order to manage environment data, to simulate the game objects, to control interactions among game objects, and to support visual authoring interface that ran define a various interrelations of the game objects. These techniques can process the autonomy level of the game objects and the associated collision avoidance method, etc. Also, it is possible to make the coherent decision-making ability of the game objects about a change of the scene. In this paper, the rule-based behavior control was designed to guide the simulation of the game objects. The rules are pre-defined by the user using visual interface for designing their interaction. The Agent State Decision Network, which is composed of the visual elements, is able to pass the information and infers the current state of the game objects. All of such methods can monitor and check a variation of motion state between game objects in real time. Finally, we present a validation of the control method together with a simple case-study example. In this paper, we design and implement the supervised classification systems for high resolution satellite images. The systems support various interfaces and statistical data of training samples so that we can select the most effective training data. In addition, the efficient extension of new classification algorithms and satellite image formats are applied easily through the modularized systems. The classifiers are considered the characteristics of spectral bands from the selected training data. They provide various supervised classification algorithms which include Parallelepiped, Minimum distance, Mahalanobis distance, Maximum likelihood and Fuzzy theory. We used IKONOS images for the input and verified the systems for the classification of high resolution satellite images.

Patient Satisfaction and Perception on Nutritional Counseling Services Quality (영양 상담서비스 품질에 대한 환자의 만족도와 인식조사)

  • Choi, Ki Bo;Lee, Song Mi;Lee, Seung Min;Lee, Eun;Park, Mi Sun;Park, Yoo Kyoung;Cha, Jin A;Lyu, Eun Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.2
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    • pp.251-258
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    • 2017
  • The objective of this study was to analyze patient satisfaction and perception of nutritional counseling services quality. A patient satisfaction and perception survey was conducted for 1,095 patients from 43 tertiary hospitals and 20 general hospitals. The number of returned questionnaires was 656 (response rate: 60.0%). Data from 633 questionnaires were analyzed after the questionnaires with unanswered items were excluded. Five domains were identified from the result of the factor analysis using the maximum likelihood and oblique rotation. The five domains were named empathy, responsiveness, tangibles, reliability, and skill and specialty. Patient perception mean score of nutritional counseling was 4.54/5.00. Patient satisfaction scores were significantly higher in empathy (P<0.001), responsiveness, and skill and specialty (P<0.01) with a college or graduate school education than in patients with a middle school education. There was no statistically significant difference between satisfaction scores in tertiary hospitals and those in general hospitals, but patients in capital hospitals reported significantly higher scores than their local counterparts in empathy, responsiveness, reliability, skill and specialty (P<0.001), and tangibles (P<0.05). In responsiveness, significantly higher (P<0.01) scores were observed in patients who received nutritional counseling only once compared to patients who received counseling two times. Patients perception of nutritional counseling services was significantly correlated with their satisfaction of five domains, reliability (r=0.721), responsiveness (r=0.697), empathy (r=0.690), skill and specialty (r=0.678), and tangibles (r=0.622).

The Relationship Between Son Preference and Fertility (남아 선호와 출산력간의 관계)

  • 이성용
    • Korea journal of population studies
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    • v.26 no.1
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    • pp.31-57
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    • 2003
  • This study is intended to examine (l)whether the value of son-for example, old age security and succession of family lineage- causing son preference in the traditional society can be explained at the individual level, (2)whether women without son in the son preference country continue her childbearing until having at least one son or give up the desire of having a son at a certain level. To accomplish these purposes, the 1974 Korean National Fertility Survey data are analyzed by the quadratic hazard models controlling unobserved heterogeneity. Unlike ordinary regression model, even omitted variables that affect hazard rates and are uncorrelated with the included independent variables can distort the parameter estimates in the hazard model. Therefore the nonparametric maximum likelihood estimator(NPMLE) of a mixing distribution developed by Heckman and Singer is used to control unobserved heterogeneity. Based on the statistical result in this study, the value of son causing son preference is determined at the societal level, not at the individual level. And Korean women without a son did not continue endlessly childbearing during child bearing ages until having a son. In general, they gave up the desire having a son when she had born six daughters continuously. Thus, 30-40 years ago, the number of daughters that women without a son giving up the desire of son was six, which is about the level of total fertility rate during 1960s. In these days, we can often see many women who have only two or three daughters and do not any son. This means that the level of giving up the desire of son, which is one factor representing the strength of son preference, becomes lower. If the strength of son preference did not become much weaker, then the fertility rates in Korea could not reach the below replacement level.

Factorial Validity of the Korean Version of the Illness Intrusive Rating Scale among Psychiatric Outpatients Mainly Diagnosed with Anxiety or Depressive Disorders (불안 및 우울장애를 주요 진단으로 하는 정신건강의학과 외래환자 대상 한국판 질병침습도 평가척도의 요인 타당도 연구)

  • Cho, Yubin;Kim, Daeho;Kim, Eunkyung;Jo, Hwa Yeon;Yun, Mirim;Lee, Hoseon
    • Korean Journal of Psychosomatic Medicine
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    • v.27 no.2
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    • pp.77-84
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    • 2019
  • Objectives : The Illness Intrusiveness Rating Scale (IIRS) is a well-validated self-report instrument for assessing negative impact of chronic illness and/or adverse effects of its treatment on everyday life domains. Although extensive literature probed its psychometric properties in medical illness, little attention was paid for its validity for psychiatric population. This study aimed to test factorial structure of the Korean Version of the IIRS (IIRS-K) in a consecutive sample of psychiatric outpatients. Methods : Data set of 307 first-visit patients of psychiatric clinic at Guri Hanyang univ. Hospital were used. Exploratory and confirmatory factor analysis, internal consistency were tested in IIRS-K. We also checked Spearman's correlation analysis between IIRS-K, Zung's self-report anxiety scale and Zung's self-report depression scale. Results : 76.9% of the patients were with anxiety disorder and depressive disorder. The principal component factor analysis of the IIRS-K extracted three-factor structure accounted for 63.2% of total variance that was contextually similar to the original English version. This three-factor solution showed the best fit when tested confirmatory factor analysis compared to the original IIRS, two-factor model of IIRS-K suggested from medical outpatients, and one-factor solution. The IIRS-K also showed good internal consistency (Cronbach's α=0.90) and good convergent validity with anxiety and depression scales. Conclusions : The IIRS-K showed the three-factor structure that was similar but not identical to original version. Overall, this study proved factorial validity of the IIRS-K and it can be used for Korean clinical population.

Genetic Parameter Estimates for Reproductive and Productive Traits of Pig in a Herd (돼지의 번식형질과 산육형질에 대한 유전모수 추정)

  • Cho, Chung-Il;Ahn, Jin-Kuk;Lee, Joon-Ho;Lee, Deuk-Hwan
    • Journal of Animal Science and Technology
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    • v.54 no.1
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    • pp.9-14
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    • 2012
  • The purpose of this study was to estimate heritabilities and genetic correlations for reproductive and productive traits and to apply their estimates to selection strategies in a swine population. Reproductive and productive traits considered in this study were number of born alive piglet (NBA), number of weaned piglet (NW), loin eye area (LEA), days to 90 kg (D90KG), back fat thickness (BF), and lean meat content (LEAN). Data were collected from 9,886 litters on 2,447 sows for reproductive traits and 10,181 gilts and boars for productive traits from Jan. 2000 to Dec. 2008 in a swine GGP farm. The statistical model to estimate genetic parameters for considering traits was a multiple traits animal model with including animal and maternal additive effects and litter effects on reproductive traits and animal additive effects on productive traits as random as well as some of fixed effects. For estimating (co) variance components of several random effects, restricted maximum likelihood methodology was used on this assumed model. The estimated heritabilities by animal additive effects and maternal effects were 0.07 and 0.02 for NBA and 0.03 and 0.02 for NW, respectively. Genetic correlation estimate for direct genetic effects between NBA and NW was 0.14. Heritability estimates for direct genetic effects were 0.19, 0.39, 0.36, and 0.43 for LEA, D90KG, BF and LEAN, respectively. The genetic correlation of LEA with LEAN was 0.35. Productive traits were antagonistically correlated with reproductive traits. From these results it is concluded that, if selection is done for strong positive effects of reproductive traits, then this would decline productive performance.