• Title/Summary/Keyword: empirical research

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Empirical Modeling of Steering System for Autonomous Vehicles

  • Kim, Ju-Young;Min, Kyungdeuk;Kim, Young Chol
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.937-943
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    • 2017
  • To design an automatic steering controller with high performance for autonomous vehicle, it is necessary to have a precise model of the lateral dynamics with respect to the steering command input. This paper presents an empirical modeling of the steering system for an autonomous vehicle. The steering system here is represented by three individual transfer function models: a steering wheel actuator model from the steering command input to the steering angle of the shaft, a dynamic model between the steering angle and the yaw rate of the vehicle, and a dynamic model between the steering command and the lateral deviation of vehicle. These models are identified using frequency response data. Experiments were performed using a real vehicle. It is shown that the resulting identified models have been well fitted to the experimental data.

Neighborhood Characteristics and Individual Health under Korean Context (한국적 특수성을 고려한 지역특성과 개인의 건강)

  • Jung, Sung-Won;Cho, Young-Tae
    • Journal of Preventive Medicine and Public Health
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    • v.38 no.3
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    • pp.259-266
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    • 2005
  • Recently much attention has been paid to the effect of neighborhood characteristics on the health of individuals, independent of individual demographic and/or socioeconomic characteristics. Although many empirical studies of a kind, mostly based on Western society, have appeared on various international journals, few studies have shown empirical evidence of neighborhood characteristics as an independent and significant risk factor of ill health in Korea. This paper discusses possible reasons that neighborhood seems to be neither significant nor substantial regarding its impact on the health of Koreans. Addressing the uniqueness of Korean society regarding the concept of neighborhood, attributes of neighborhoods, and methodological challenges, authors suggest that more sophisticated conceptual and methodological approach, specific to Korean society, should enable to reveal the effect of neighborhood characteristics on individual health in Korea.

A Study on the Empirical Model for Predicting the Physical Suitability of Office Chairs (사무용 의자의 물리적 적합도 예측 모델링에 관한 연구)

  • 김진호;이현우;박수찬
    • Journal of Korean Society for Quality Management
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    • v.29 no.3
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    • pp.151-165
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    • 2001
  • The purpose of this study is to develop systematic methods for evaluating the suitability of a seat and build an empirical model for predicting the suitability of a seat. The following research schemes were pursued to achieve the objectives - Development of suitable chair dimensions - Analysis scheme for decomposing the human-product interface system - Development of model for evaluating suitability. As a result, we uncovered six dominant suitability dimensions for the design of a comfortable seat that is related to the physical dimension of a body, Here, six suitability dimensions were identified as the dimensions that represent the human sensitivity and psychological feeling on comfortable seats. Also, 43 human-interface elements (HIE's) such as seat height, seat width, seat depth, tilting angle, seat surface etc. were investigated. HIE was generally defined as the physical characteristic of manufacturing goods, and it had close related to the body dimension of a user and environment that it was used.

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A Study on a plan of Beverage Sales Step-up of Family Restaurant in Korea. (Family Restaurant의 음료 매출증대에 관한 연구)

  • 이재련
    • Culinary science and hospitality research
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    • v.6 no.3
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    • pp.425-442
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    • 2000
  • The main purpose of this study is to propose that Beverage sales should be step-up in Family Restaurant. To achieve the purpose of this study theoretical and empirical approaches were used. In review of theoretical background, basic concepts and characteristics of beverage were studied. For empirical study, three Family Restaurant in Korea was selected and analyzed the beverage sales which classified to Liquor, Beer Wine and Non-alcoholic beverage. Based on it, I suggest a plan of beverage sales step-up of Family Restaurant as follow. First, keep the appropriate valance of the whole item: non-alcohol and alcohol item. Second, develop the menu should be effect beverage sales. Third, through the promotion and event the restaurant should derive the customer to purchasing behavior. Fourth. server can accommodate and offer the information of food and beverage menu that can evoke the customer's attention.

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The Effects of Competitiveness on Telecommunication Service Quality (경쟁도입 및 경쟁심화가 유선통신 서비스품질에 미치는 영향에 관한 탐색적 연구 - 국제전화사업을 중심으로 -)

  • Park, Ki-Nam;Lee, Hoon-Young
    • Asia pacific journal of information systems
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    • v.10 no.3
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    • pp.145-157
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    • 2000
  • Economists have advocated that the market competitiveness improved the firm's productivity and eventually its service quality. However, the previous researches did not provide the empirical results enough to prove that the competitiveness do improve the service quality. In this paper, we conducted an empirical research to find whether the competition induces the quality of service. The telecommunication industry was chosen since it went through the increasing competition along with a high attention. We found that competition itself does not guarantee the quality of service. It is the intensity of competition that improves the service quality. The service quality depends mainly on the competitor's competence, i.e. the intensity of competition rather than the competition itself. In sum, when we want tc improve the service quality as well as the productivity, we had better increase the intensity of competition by allowing many new strong entities.

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Government-owned Bank Relationships and Firm Performance (정부소유 은행관계와 기업 경영성과)

  • Lee, Sang Wook
    • Knowledge Management Research
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    • v.14 no.1
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    • pp.57-72
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    • 2013
  • This paper examines the relationships between the Korean government-owned banks and the firm performance. We investigates this empirical analysis using a data set containing virtually all Korean publicly listed firms for the period of 2004-2006. We find the negative relationships between government-owned banks and firm performance. The strong relationships between the Korean government-owned banks and the Korean listed firms may lower firm performance. The Hold up costs may be present in the government-owned bank relationships. The government-owned bank relationships in the Korean listed firms may could shape the negative management decisions and firm performance. On the lines of concerns on the impact of government banks, this paper will provide new evidences on the impact of government-ownership of banks on the Korean Economy. Particularly, empirical analyses in this paper revealed new evidences on the recent firm-bank relationship or government banks researches.

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An Analysis of the Factors Affecting Farmers' Recognition and Acceptance on Sustainable Agriculture (지속가능한 농업 인식도 및 수용의향 분석)

  • Kim, Chang-Gil;Jeong, Hak-Kyun;Moon, Dong-Hyun;Han, Jae-Hwan
    • Korean Journal of Organic Agriculture
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    • v.23 no.2
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    • pp.247-265
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    • 2015
  • This study analyzes the factors affecting farmers' recognition and acceptance of sustainable agriculture. To accomplish the objectives of the study a farm survey was conducted using target respondents which were made of the local correspondents and reporters of Korea Rural Economic Institute. The Heckman's model was employed for an empirical analysis on determining the extent of farmers' acceptance of sustainable agriculture. The analysis results show that the more farmers think it is important for Korea to adopt sustainable farming practices, the more they adopt sustainable agriculture. It is also shown that the high incomes farmers earn, the more interest they have in the environment and thus the more likely they are to adopt sustainable agriculture. Based upon the empirical results it is suggested that an adoption of economic incentive instruments, education of sustainable agriculture, research and development of sustainable agriculture technology, and an establishment of sustainable agriculture infrastructure to expand the scale of sustainable agriculture.

A Classification of Conversion Factors of Relative Values in the National Health Insurance (건강보험 환산지수의 유형별 분류방안)

  • Kim, Jin-Hyun;Choi, Byung-Ho
    • Journal of Society of Preventive Korean Medicine
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    • v.10 no.2
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    • pp.147-158
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    • 2006
  • The purpose of this paper is to review the empirical study results of conversion factors(unit prices) for relative values of health care services in the national health insurance system and establish optimal classification of health care institutions for feasible contract of conversion factors between National Health Insurance Corporation(NHIC) and provider groups, based on legal backgrounds and types of health care service delivery system. some empirical research evidences shows the validity of applying multiple conversion factors to annual contract for reimbursement in the national health insurance. Policy recommendations suggest that clinic, hospital, general hospital, tertiary hospital, dental clinic, oriental medical clinic, pharmacy, and public health centers would be a basic category of provider groups for a meaningful price contract between the NHIC and providers.

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Comparison of Structural Change Tests in Linear Regression Models

  • Kim, Jae-Hee
    • The Korean Journal of Applied Statistics
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    • v.24 no.6
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    • pp.1197-1211
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    • 2011
  • The actual power performance of historical structural change tests are compared under various alternatives. The tests of interest are F, CUSUM, MOSUM, Moving Estimates and empirical distribution function tests with both recursive and ordinary least-squares residuals. Our comparison of the structural tests involves limiting distributions under the hypothesis, the ability to detect the alternative hypotheses under one or double structural change, and smooth change in parameters. Even though no version is uniformly superior to the other, the knowledge about the properties of those tests and connections between these tests can be used in practical structural change tests and in further research on other change tests.

Application of Constrained Bayes Estimation under Balanced Loss Function in Insurance Pricing

  • Kim, Myung Joon;Kim, Yeong-Hwa
    • Communications for Statistical Applications and Methods
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    • v.21 no.3
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    • pp.235-243
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    • 2014
  • Constrained Bayesian estimates overcome the over shrinkness toward the mean which usual Bayes and empirical Bayes estimates produce by matching first and second empirical moments; subsequently, a constrained Bayes estimate is recommended to use in case the research objective is to produce a histogram of the estimates considering the location and dispersion. The well-known squared error loss function exclusively emphasizes the precision of estimation and may lead to biased estimators. Thus, the balanced loss function is suggested to reflect both goodness of fit and precision of estimation. In insurance pricing, the accurate location estimates of risk and also dispersion estimates of each risk group should be considered under proper loss function. In this paper, by applying these two ideas, the benefit of the constrained Bayes estimates and balanced loss function will be discussed; in addition, application effectiveness will be proved through an analysis of real insurance accident data.