• Communications for Statistical Applications and Methods
• /
• v.25 no.6
• /
• pp.577-590
• /
• 2018

Employing the covariance adjustment technique, we show that in the system of two seemingly unrelated multivariate regressions the estimator of regression coefficients can be expressed as a matrix power series, and conclude that the matrix series only has a unique simpler form. In the case that the covariance matrix of the system is unknown, we define a two-stage estimator for the regression coefficients which is shown to be unique and unbiased. Numerical simulations are also presented to illustrate its superiority over the ordinary least square estimator. Also, as an example we apply our results to the seemingly unrelated growth curve models.

• Korea Trade Review
• /
• v.44 no.2
• /
• pp.51-62
• /
• 2019

This study predicts the future world seaborne trade volume with econometrics methods using 23-year time series data provided by Clarksons. For this purpose, this study uses simple regression analysis, exponential smoothing method and seemingly unrelated regression model (SUR Model). This study is meaningful in that it predicts worldwide total seaborne trade volume and seaborne traffic in four major items (container, bulk, crude oil, and LNG) from 2019 to 2023 as there are few prior studies that predict future seaborne traffic using recent data. It is expected that more useful references can be provided to trade related workers if the analysis period was increased and additional variables could be included in future studies.

• The Korean Journal of Applied Statistics
• /
• v.29 no.4
• /
• pp.627-641
• /
• 2016

In this paper, we consider a seemingly unrelated regression (SUR) model and propose a nonparametric Bayesian approach to SUR with a Dirichlet process mixture of normals for modeling an unknown error distribution. Posterior distributions are derived based on the proposed model, and the posterior inference is performed via Markov chain Monte Carlo methods based on the collapsed Gibbs sampler of a Dirichlet process mixture model. We present a simulation study to assess the performance of the model. We also apply the model to precipitation data over South Korea.

• Industrial Engineering and Management Systems
• /
• v.15 no.4
• /
• pp.318-323
• /
• 2016

In the current study, factors affecting cheese brands products in grocery stores were evaluated with an emphasis on diversity. The sample data were collected from Noushad and Pegah Milk Industry in 2015 and data were extracted, reviewed, and analyzed from 435 grocery stores in Mashhad using seemingly unrelated regression model and particle swarm optimization algorithm. Results showed that optimum amount of Kalleh product diversity is higher than other competitors in the market, and Kalleh UF diversity is 100 to 250 grams, and Kalleh UF diversity with weight of 300 to 500 grams is more than other modes of diversity, and Kalleh brand must remove tin cheese from the market. Sabah Brand also should eliminate its glass and creamy diversity from market, UF diversity is mostly welcomed in market.

• Journal of the Economic Geographical Society of Korea
• /
• v.12 no.2
• /
• pp.142-158
• /
• 2009

The purpose of this paper is to identify determinants of regional export in Korea using the interregional input-output table and SUR(Seemingly Unrelated Regression) model. Regional exports are classified into four groups; intraindustry intraregional export, interindustry intraregional export, intraindustry interregional export and interindustry interregional export. Labor productivity, scale economies, market size, and international trade volumes have positively influenced regional exports while the interregional distances having a negative effect on them. These results imply that it is necessary to operate regional strategies to enhance productivities and market size and to reduce transportation and distribution costs for revitalize a regional economy by increasing regional exports.

• Journal of Korean Society of Forest Science
• /
• v.98 no.2
• /
• pp.148-155
• /
• 2009

The objective of this study is to know market structures of softwood logs being imported to South Korea from log producing countries. Import demand of softwood logs imported to South Korea from America, New Zealand and Chile is fixed as a function of log prices, the lagged dependent variable and output. On the basis of the adaptive expectations model, linear regression models that the explanatory variables included and the lagged dependent variable were estimated by Seemingly Unrelated Regression Equations (SURE). The short-run and long-run own price elasticity of America's softwood log import demand is -1.738 and -4.250 respectively. Then long-run elasticity is much higher than short-run elasticity. Short-run and long-run crosselasticity of New Zealand's softwood log import demand with respect to American's softwood log import price are inelastic at 0.505 and 0.883 respectively. Short-run and long-run cross-elasticity of Chile's softwood log import demands with respect to American's softwood log import prices were highly elastic at 2.442 and 4.462 respectively. Long-run elasticity was almost twice as high as short-run elasticity.

• Journal of Forest and Environmental Science
• /
• v.36 no.1
• /
• pp.7-16
• /
• 2020

Tree size distribution modelling is an integral part of forest management. Most distribution yield systems rely on some flexible probability models. In this study, a simple finite mixture of two components two-parameter Weibull distribution was compared with complex four-parameter distributions in terms of their fitness to predict tree size distribution of teak (Tectona grandis Linn f) plantations. Also, a system of equation was developed using Seemingly Unrelated Regression wherein the size distributions of the stand were predicted. Generalized beta, Johnson's SB, Logit-Logistic and generalized Weibull distributions were the four-parameter distributions considered. The Kolmogorov-Smirnov test and negative log-likelihood value were used to assess the distributions. The results show that the simple finite mixture outperformed the four-parameter distributions especially in stands that are bimodal and heavily skewed. Twelve models were developed in the system of equation-one for predicting mean diameter, seven for predicting percentiles and four for predicting the parameters of the finite mixture distribution. Predictions from the system of equation are reasonable and compare well with observed distributions of the stand. This simplified mixture would allow for wider application in distribution modelling and can also be integrated as component model in stand density management diagram.

• Korean Journal of Agricultural Science
• /
• v.47 no.2
• /
• pp.291-303
• /
• 2020

This various factors that affect beef consumption behavior between different types of beef such as Hanwoo, Australian, American, and domestic Yukwoo. Previous studies usually used almost ideal demand system (AIDS) model to show the degree of substitution between meats especially domestic and foreign beef. This a real expenditure each individual and to explain what factors affect consumers especially focusing on various beef. Hence, previous studies used shares and prices as key variableshowever, this study use various socio-demographic variables, consumption tendency, satisfaction and importance for beef consumption, purchasing usage and part, etc. This study a seemingly unrelated regression (SUR) model to enhance efficiency of estimates because error terms of four beef consumption equations are correlated. For, an on-line survey was performed Aug. 5 - 14, and we obtained 979 effective samples. The results show that high income group (more than 700 mil. won per month) purchases more beef than other groups. The origin of orders is Hanwoo, Yukwoo, Australian beef, and American beef. A family who member purchases more Yukwoo than other groups. foreign affects beef consumption regardless of its origin. Individuals who think origin and taste prefer Hanwoo. However, individuals who think price prefer Australian beef.

• The Journal of Fisheries Business Administration
• /
• v.53 no.1
• /
• pp.73-84
• /
• 2022

The purpose of this study is the impact of national fishing port investment and typhoons on fisheries disaster damage. The dependent variables were the amount of damage to fishing ports, fishing boats, fisheries enhancement, external facilities, mooring facilities, functional facilities, fishing port and typhoons. The analysis period is from 2002 to 2018. Since the error term is in a simultaneous correlation, it was efficiently estimated by analyzing it with a seemingly unrelated regression (SUR) method. As a result of the analysis, external facilities have not significance to all models. Investing in mooring facilities increased the amount of damage to fishing ports for five years. Investing in functional facilities reduced the amount of damage to fishing ports and aquaculture over five years. Typhoons have significance to all models, and the amount of damage increased every time a typhoon occurred. Based on these results, as the influence of typhoons increases, it seems necessary to establish preventive measures. Timely investment and maintenance to enable the role and function of national fishing ports are considered important.

• Journal of Korean Society of Rural Planning
• /
• v.30 no.1
• /
• pp.99-106
• /
• 2024

The purpose of this study is to analyze how the orchard scale improvement project affects the profits of apple farmers. For this purpose, the variable profit function of Apple was estimated using seemingly unrelated regression analysis. For the analysis, raw data from the Rural Development Administration's Agricultural Income Survey from 2015 to 2021 were used. Of the 1,009 apple farms, 95 farms participated in the orchard scale improvement project and 914 farms did not participate. The results show that the profits of farms participating in the project were found to be higher than those of non-participating farms, and as the cultivation area increased, profits tended to increase and then decrease. The results also indicated that below a certain size (19,462m²), the profits from project participation appear to be lower. The results of this study can provide useful information to the establishment of government policies and apple farmers who want to participate in the orchard scale improvement project.