• Title/Summary/Keyword: Empirical studies

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Binary classification on compositional data

  • Joo, Jae Yun;Lee, Seokho
    • Communications for Statistical Applications and Methods
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    • v.28 no.1
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    • pp.89-97
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    • 2021
  • Due to boundedness and sum constraint, compositional data are often transformed by logratio transformation and their transformed data are put into traditional binary classification or discriminant analysis. However, it may be problematic to directly apply traditional multivariate approaches to the transformed data because class distributions are not Gaussian and Bayes decision boundary are not polynomial on the transformed space. In this study, we propose to use flexible classification approaches to transformed data for compositional data classification. Empirical studies using synthetic and real examples demonstrate that flexible approaches outperform traditional multivariate classification or discriminant analysis.

Amplification based on shear wave velocity for seismic zonation: comparison of empirical relations and site response results for shallow engineering bedrock sites

  • Anbazhagan, P.;Aditya, Parihar;Rashmi, H.N.
    • Geomechanics and Engineering
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    • v.3 no.3
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    • pp.189-206
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    • 2011
  • Amplification based on empirical relations is widely used for seismic microzonation of urban centers. Amplifications are used to represent the site effects of a particular soil column. Many empirical correlations are available to estimate the amplification of seismic waves. These correlations are based on the ratio of shear wave velocity of foundation/rock to soil velocity or 30 m equivalent shear wave velocity ($Vs^{30}$) and are developed considering deep soil data. The aim of this work is to examine the applicability of available amplification relations in the literature for shallow engineering bedrock sites by carrying out site response studies. Shear wave velocity of thirteen sites having shallow engineering bedrock have been selected for the study. In these locations, the depth of engineering bedrock (> 760 ${\pm}$ 60 m/s) is matched with the drilled bore hole. Shear wave velocity (SWV) has been measured using Multichannel Analysis of Surface Wave survey. These sites are classified according to the National Earthquake Hazards Reduction Program (NEHRP) classification system. Amplifications for an earthquake are arrived for these sites using empirical relations and measured SWV data. Site response analysis has been carried out in SHAKE using SWV and using synthetic and real earthquake data. Amplification from site response analysis and empirical relations are compared. Study shows that the amplification arrived using empirical relations does not match with the site response amplification. Site response amplification is much more than empirical values for same shear wave velocity.

A Study on Mathematical Justification of Elementary School Teachers (초등학교 교사들의 수학적 정당화에 대한 연구)

  • Kim, Jeong-Ha;Kang, Moon-Bong
    • Journal of Educational Research in Mathematics
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    • v.19 no.3
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    • pp.371-392
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    • 2009
  • A lot of researches state mathematical justification is important. Specially, NCTM (2000) mentions that mathematical reasoning and proof should be taught every student from pre-primary school to 12 grades. Some of researches say elementary school students are also able to prove and justify their own solution(Lester, 1975; King, 1970, 1973; Reid, 2002). Balacheff(1987), Tall(1995), Harel & Sowder(1998, 2007), Simon & Blume(1996) categorize the level or the types of mathematical justification. We re-categorize the 4 types of mathematical justification basis on their studies; external conviction justification, empirical-inductive justification, generic justification, deductive justification. External conviction justification consists of authoritarian justification, ritual justification, non-referential symbolic justification. empirical-inductive justification consists of naive examples justification and crucial example justification. Generic justification consists of generic example and visual example. The results of this research are following. First, elementary school teachers in Korea respectively understand mathematical justification well. Second, elementary school teachers in Korea prefer deductive justification when they justify by themselves, while they prefer empirical-inductive justification when they teach students.

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An empirical study of evaluating the Korean firm's technological knowledge assets (한국 기업의 기술지식자산 평가에 대한 실증연구)

  • 윤찬병;하형철;박용태
    • Proceedings of the Technology Innovation Conference
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    • 1999.06a
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    • pp.85-97
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    • 1999
  • Being the new paradigm of "knowledge based economy", knowledge asset get to be the key to evaluate the firm's value. For a instance, Scandia firstly informed the intellectual capital report with its own financial statements in 1994. Some financial institutions have emphasized the roles of knowledge assets in the evaluating firm's value, too. But the concept of knowledge asset is so extensively defined that the result of evaluation is not as much reliable as financial statements. As previous studies examined the firm-specific cases, the sectoral pattern of knowledge asset has been ignored and it cause the difficulty in the empirical study. Moreover, the objectivity of study is ambiguous. Therefore, we regards knowledge asset as a technological knowledge asset. Which is related to R&D(research & development) and technology. Because this definition is more measurable than others and can play a frontier role in evaluating the knowledge asset. We extract the criteria related to the technological knowledge asset through the survey of 'Scandia' and other previous studies and add other criteria, which explain the Korean-specific environments. We gather data from "Technological Innovation"(STEPI, 1997, 1999) and "The bibliography of Korean R&D institutes"(KITA,1998) and "the survey of listed company"(Daewoo Securities, 1998. 1999). As the results of empirical study, the variables which explain the financial value of firms do not reflect the 'technological knowledge asset' well. It results from the factors as followings. Firstly, instead of stock price the proxy measurement related to 'knowledge asset' is needed. Secondly, the sample is biased to the large scale firms so we'll collect samples more broadly. Finally, the concept of 'technological knowledge asset' is too narrow to explain the value of firm. We expect the result of this empirical study gives contribution to the evaluation of firms' value more exactly.

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The Moderating Effects of Specificity of Technology in the Knowledge Transfer of Distributive Manufacturing MNEs (유통제조 기업의 해외 자회사 지식이전에서 기술특유성의 조절효과)

  • Cho, Yeon-Sung
    • Journal of Distribution Science
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    • v.14 no.9
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    • pp.121-132
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    • 2016
  • Purpose - This study has the following objectives. First, it seeks to build an integrated model that can analyze the path through which headquarters, subsidiary competence, and knowledge transfer performance influence subsidiary performance. Second, it analyzes the influence of the specificity of technology as a moderating effect factor on knowledge transfer process. Third, it will conduct an empirical analysis on distributive manufacturing MNEs and suggests an implication for companies that actually need technological localization. The difference of this study are as follows. First, unlike the existing studies, this study can expand a theoretical discussion as it uses subsidiary performance as the dependent variable. Second, it sets the specificity of technology as a moderating effect factor, not an antecedent, and can draw a theoretical implication. Research design, data, and methodology - This study built a path analysis model to identify the influence of the disseminative capacity and absorptive capacity of distributive manufacturing MNEs on subsidiary performance. Based on the previous studies, it set 19 items as 5 latent variables, and established 6 hypotheses by including the moderating effect of the specificity of technology between them. The final 203 companies were selected as analysis samples through a survey questionnaire. For empirical analysis, the study used PLS (Partial Least Square) that is based on structural equation model. Results - The empirical analysis result demonstrated that both headquarters' disseminative capability and subsidiaries absorptive capacity had a positive influence on knowledge transfer performance. Knowledge transfer performance also had a positive influence on subsidiary performance. In the analysis of moderating effect, the specificity of technology acted as a significant moderating variable only between knowledge transfer performance and subsidiary performance; it did not show a statistically significant moderating effect among disseminative capability, absorptive capacity, and knowledge transfer performance. Conclusions - The empirical analysis results of this study demonstrate the importance of disseminative capability and absorptive capacity in knowledge transfer to subsidiaries from the distributive manufacturing MNEs in Korea. The analysis on the moderating effect indicates that the specificity of technology in Korean companies influences on the process of making achievement by using the transferred knowledge.

The Determinants of Foreign Direct Investment in the Mining Sector: A Panel Analysis (광업부문에 대한 외국인직접투자 결정요소: 패널 분석)

  • Ulzii-Ochir, Nomintsetseg;Sohn, Chan-Hyun
    • International Area Studies Review
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    • v.15 no.3
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    • pp.145-174
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    • 2011
  • Attracting foreign direct investment in the mining sector becomes a key factor for the continuing economic growth for mining-dependent developing countries. This paper attempts to identify the determining factors that attract FDI inflows into the mining sector. Based on previous conceptual studies, the authors have attempted empirical analyses on a panel of 40 mining countries for the period 1996-2009. These empirical results are the first of their kind given the variables employed are arguably the most comprehensive and exhaustive to date. The empirical results show that market size, trade openness, quality of mined products, quality of infrastructure, regulatory quality, and perceived economic risk associated with the country are positively related to investments in mining. Whereas, tariff rate, corporate tax rate, extent of corruption, and political instability are negatively related to FDI inflows in the mining sector. The empirical results also show that developing countries tend to attract greater amounts of FDI in the mining sector compared to their developed counterparts.

Has Container Shipping Industry been Fixing Prices in Collusion?: A Korean Market Case

  • Jaewoong Yoon;Yunseok Hur
    • Journal of Korea Trade
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    • v.27 no.1
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    • pp.79-100
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    • 2023
  • Purpose - The purpose of this study is to analyze the market power of the Korea Container Shipping Market (Intra Asia, Korea-Europe, and Korea-U.S.) to verify the existence of collusion empirically, and to answer whether the joint actions of liner market participants in Korea have formed market dominance for each route. Precisely, it will be verified through the Lerner index as to whether the regional market of Asia is a monopoly, oligopoly, or perfect competition. Design/methodology - This study used a Lerner index adjusted with elasticity presented in the New Imperial Organization (NEIO) studies. NEIO refers to a series of empirical studies that estimate parameters to judge market power from industrial data. This study uses B-L empirical models by Bresnahan (1982) and Lau (1982). In addition, NEIO research data statistically contain self-regression and stability problems as price and time series data. A dynamic model following Steen and Salvanes' Error Correction Model was used to solve this problem. Findings - The empirical results are as follows. First, λ, representing market power, is nearly zero in all three markets. Second, the Korean shipping market shows low demand elasticity on average. Nevertheless, the markup is low, a characteristic that is difficult to see in other industries. Third, the Korean shipping market generally remains close to perfect competition from 2014 to 2022, but extreme market power appears in a specific period, such as COVID-19. Fourth, there was no market power in the Intra Asia market from 2008 to 2014. Originality/value - Doubts about perfect competition in the liner market continued, but there were few empirical cases. This paper confirmed that the Korea liner market is a perfect competition market. This paper is the first to implement dynamics using ECM and recursive regression to demonstrate market power in the Korean liner market by dividing the shipping market into Deep Sea and Intra Asia separately. It is also the first to prove the most controversial problems in the current shipping industry numerically and academically.