• Journal of the Korean Data and Information Science Society
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• 제20권6호
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• pp.1093-1101
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• 2009

분위수 회귀모형은 확률변수들 사이에 확률적인 관계구조를 포함한 함수 모형을 좀 더 완벽하게 추정하도록 제공한다. 본 논문에서는 함수 추정에 로버스트하다고 알려져 있는 서포트벡터기계 기법과 이중벌칙커널기계를 이용하여 분위수 회귀모형을 추정하고자 한다. 이중벌칙커널기계는 고차원의 입력변수에 대한 분위수 회귀가 요구될 때 분위수 회귀모형을 잘 추정한다고 알려져 있다. 또한 본 논문에서는 광범위한 형태의 분위수 회귀모형 추정을 위해서 정규분포보다 비대칭 라플라스 분포를 이용한다. 본 논문에서 제안한 모형은 분위수 회귀모형 추정을 위해서 서포트벡터기계 기법에 이중벌칙커널기계를 이용하여 각각의 평균과 분산을 동시에 추정한다. 평균과 분산함수 추정을 위해 사용된 커널함수의 모수들은 최적의 값을 찾기 위해 일반화근사 교차타당성을 이용한다.

• 지질공학
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• 제3권1호
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• pp.51-61
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• 1993

비정상 현상을 나타내는 지하수위 자료의 추정을 위해서 제한적 최대 우도치를 이용하는 universal kriging을 사용하였다. 제한적 최대우도법의 우수성을 판정하기 위해 가중 최소자승법을 이용하는 IRD-k와 비교 검토하였다. 교차 타당성에 있어서 RML과 k계 고유 확율함수는 거의 비슷한 결과를 갖고, 참값 대 추정치의 이산분포도와 지하수위 등고선도에 있어서도 2가지 방법이 거의 같은 결과를 만들었다. RNL을 이요한 universal kriging과 가중 최소자승법을 이용한 IRF-k가 비정상 함수자료의 추정에 있어서 거의 비슷한 결과를 만든 원인은 이용된 실험자료의 비정규분포와 적은 자료수에 기인하는 것으로 사료된다.

• 한국정보처리학회논문지
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• 제6권9호
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• pp.2343-2349
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• 1999

최근에 개발되어 성공적으로 적용되고 있는 초기하분포 소프트웨어 신뢰성 성장 모델은 이 모델에서 중요한 역할을 하는 반응계수(sensitivity factor)를 추정 대상인 모수로 가정하고 있다. 본 논문은 먼저 디버깅과정의 무작위성을 반영하기 위해 반응계수를 이항분로를 하는 확률변수로 가정하여 초기하분포 신뢰성 성장 모델을 일반화한다. 이러한 일반화는 초기하분포 소프트웨어 신뢰성 성장 모델의 통계적 특성을 쉽게 파악할 수 있게 한다. 특히 일반화 된 모델의 모수를 최소자승법으로 추정하면 기존 모델에 최소자승법을 적용한 것과 같은 결과를 얻을 수 있음을 보이고, 더불어 최우추정치를 최소자승법으로 구하는 방법과 예측방법도 제시한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.517-525
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• 2021

The study investigates the behavior of Asian banks in response to the subprime mortgage crisis and examines how countries that have experimented with a mix of conventional and Islamic banking managed their balance sheet during that period. The study carries out an independent mean t-test comparing the difference of leverage of 464 conventional commercial Asian banks pre- and post-crisis from the largest twenty-five Asian economies based on GDP (2007). The analysis uses 10-year unbalanced panel data of conventional banks and employs the generalized least squares estimation using a dummy variable event window method to capture the response of Asian banks. The study finds evidence of a structural change in the capital structure of Asian commercial banks in response to the financial crisis. Findings suggest that conventional banks increased their capital position more in countries that have both Islamic and conventional banking than those countries without Islamic banking services. By having Islamic banking in their product portfolio, countries can exert market discipline on conventional banks. The study identifies a significant role of global macroeconomic shocks on banks liability structure decision-making. Evidence shows that this increase in capital positioning by banks was a permanent rather than a temporary response.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.819-826
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• 2021

This study aims to determine the impact of product consumption strategy and financial autonomy on the competitiveness of technology firms in Vietnam. This study employs panel data of 27 technology firms collected from listed financial statements of the business for the period (2010-2019). The study also uses some indicators reflecting the macroeconomic situation of the economy collected from the World Bank. Instead of Exploratory Factor Analysis which has been used before, the study uses the feasible generalized least squares (FGLS) estimation as the main method. The FGLS corrects the variance changes and autocorrelation on the dataset of these Vietnamese technology firms. The results reveal that the strategy of product consumption and financial autonomy positively affect the competitiveness of technology firms. These are also two core factors of the technology industry, which have a strong impact on the increase in the competitiveness of firms. The findings of this study suggest that technology firms do not need to invest in many long-term assets, but mainly in short-term assets in order to quickly respond to the strategies for consuming new technology products of the business. In addition, the increase in Gross Domestic Product per capita also positively affects the increase in the competitiveness of technology firms.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.411-417
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• 2021

This study aims to estimate the production function and total factor productivity (TFP) of Vietnamese seafood processing firms. At the same time, the study analyses the impact of internal factors of firms and the quality of economic institutions on the TFP of the Vietnamese seafood processing industry. The study uses the Function Control (FC) approach in TFP estimation and the Feasible Generalized Least Squares (FGLS) regression model in the analysis of factors affecting TFP. The study was carried out on the census data of enterprises of the Vietnamese seafood processing industry collected by the Vietnamese General Statistics Office and Provincial Competitiveness Index data of Vietnam Chamber of Commerce and Industry in the period from 2013 to 2018. Estimated results from the models show that: i) Vietnamese seafood processing firms are, currently, mainly labor-intensive, the TFP contribution and output is only about 2.258. ii) Factors such as the firm's age, firm's size, and the firm's ownership affect TFP. In which, firms that have few numbers of years of operation, small and medium firms, and private firms have low TFP. iii) Institutional quality and the provincial business environment have a positive impact on the TFP of Vietnamese seafood processing firms in this period.

• Journal of Korea Trade
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• 제27권1호
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• pp.159-175
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• 2023

Purpose - This paper empirically investigates the relationship between born global strategy and the accounting- and market- based financial performance of Korean firms. Further, this study identifies the characteristics of born global firms (BGs) in comparison with non-BG counterparts in terms of size, R&D, and liability. Design/methodology - Using a database of listed Korean SMEs in the manufacturing sector from 2010 to 2020, this study applies panel generalized least squares (GLS) estimation and logistic regression techniques. Findings - This study finds that BG strategy is negatively related to the firm's accounting-based financial performance, while it is positively related to the market-based financial performance. This study also finds that BGs have higher sales volume and more total assets compared to their non-BG counterparts. In addition, Korean BGs spend more on R&D, and at the same time have higher liability. Originality/value - BGs, by definition, are firms that are actively penetrating foreign markets from the early stages of their establishment. Previous studies of Korean BGs have tried to identify the determinants of BGs' rapid internationalization and their superior performance. However, most of these studies have utilized either qualitative case- or survey-based analyses with relatively limited numbers of observations. From a different perspective, this study provides more objective evidence by investigating how the BG strategy affects the financial and market performance of firms, and by characterizing BGs in terms of financial data.

• Steel and Composite Structures
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• 제49권4호
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• pp.407-417
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• 2023

After a disaster like the catastrophic earthquake, the government have to use rapid assessment of the condition (or damage) of bridges, buildings and other infrastructures is mandatory for rapid feedbacks, rescue and post-event management. Many domain schemes based on the measured vibration computations, including least squares estimation and neural fuzzy logic control, have been studied and found to be effective for online/offline monitoring of structural damage. Traditional strategies require all external stimulus data (input data) which have been measured available, but this may not be the generalized for all structures. In this article, a new method with unknown inputs (excitations) is provided to identify structural matrix such as stiffness, mass, damping and other nonlinear parts, unknown disturbances for example. An analytical solution is thus constructed and presented because the solution in the existing literature has not been available. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage. Simulation results of linear and nonlinear structures show that the proposed method is able to identify structural parameters and their changes due to damage and unknown excitations. Therefore, the goal is believed to achieved in the near future by the ongoing development of AI and control theory.

• 한국프랜차이즈경영연구
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• 제14권4호
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• pp.35-50
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• 2023

Purpose: This study aims to uncover the mechanism of how initial fees are determined in the restaurant franchise business. Since the initial fees can be considered as a price of utilizing business models and operational knowledge of a certain franchise brand, it is critical to understand the fee decision-making process based on the strategic pricing theories. Therefore, this study investigates the influence of operational value on the determination of initial franchise fees grounded on a value-based pricing strategy. The Operational value is specifically categorized into profitability, growth, and stability of the franchise system. Research design, data, and methodology: The data used were collected through franchise disclosure documents and brand equity index provided by Korea Management Association Consulting. Data from 44 franchise restaurants during 2018 to 2021 are included in the sample. The panel dataset was analyzed by using generalized least squares estimation with R-Studio. Results: Profitability and stability positively influence initial franchise fees. However, growth did not influence initial franchise fees. Conclusions: The results of the study demonstrate that the operational value plays a critical role in determining the franchise fees. Specifically, franchisees recognize how much revenue a franchise system generates for them (i.e., profitability) and how stable the entire system is for operating business (i.e., stability) when they make purchasing decisions for franchise. The findings extend the pricing literature by applying pricing theories in the franchise fee context. Also, the study contributes to franchising and restaurant management literature by providing knowledge of how franchise fees are determined.

• 대한교통학회지
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• 제18권4호
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• pp.117-126
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• 2000

링크에서 관측된 교통량과 기존의 기종점표(Origin-Destination matrix)를 결합해 새로운 OD를 추정하고자 하는 연구들은 1980년대부터 20여년간 많은 연구자들을 통해 논의되어 왔다. 특히 최근들어 ITS 등의 보급으로 교통관리를 위한 기본자료로서 링크 교통량의 관측이 확대되면서, 도시고속도로 및 간선도로 관리, 경로안내 시스템 등에 사용될 목적으로 링크관측교통량 자료를 이용한 OD 추정의 필요성이 더욱 높아지고 있다. OD 추정을 위해 사용되는 기존기법으로는 여러 가지가 있으나 가장 대표적인 기법으로는 베이지안 추정을 이용하는 통계적 방법(Maher, 1983), Entropy 극대화 규칙을 이용하는 방법(Van Zuylen and Willumsen, 1980; Fisk and Boyce, 1983; Fisk, 1989), 최우추정법을 이용한 방법(Spiess, 1987), 그리고 일반화 최소자승법을 이용하는 방법(Gothe et al., 1989; Bell, 1997; Yang et al., 1992) 등이 있다. 본 연구에서는 이러한 방법들 중 최소자승법을 이용해 OD추정모형을 구축하고, 최적해를 얻기 위하여 유전알고리즘(Genetic Algorithm)을 이용한 알고리즘을 개발하였다 또한, 개발된 모형을 통해 얻은 결과를 Spiess(1990)가 제시하여 현재 EMME/2에서 사용되고 있는 Gradient method의 결과와 비교하였다. 본 연구에서는 모형의 추정력 비교를 위해 각 기종점 통행량의 평균 추정오차 외에 동일한 기점을 갖는 기종점 통행량 간의 규모순위(OD 구조) 추정력을 확인하였다. 서울시 내부순환도로를 분석대상으로 하여, 대상지역에서 오전에 조사된 OD를 기존(Target) OD로 사용하였고, 오후의 OD를 추정대상 OD로 설정하였으며, 각 링크에서 오후에 조사된 실제교통량을 링크 관측교통량으로 사용하였다. 분석결과 유전알고리듬을 이용한 최소자승법을 통해 얻은 결과가 Gradient method를 통해 얻은 결과에 비해 우수한 것으로 나타났다.