• Korean System Dynamics Review
• /
• v.8 no.2
• /
• pp.25-49
• /
• 2007

An important assumption of the classical linear regression model is that the disturbances appearing in the population regression function are homoskedastic; that is, they all have the same variance. If we persist in using the usual testing procedures despite heteroskedasticity, what ever conclusions we draw or inferences we make be very misleading. The contribution of this paper will be to the concrete procedure of the proper estimation when the heteroskedasticity does exist in the data, because the quality of dependent variable predictions, i.e., the estimated variance of the dependent variable, can be improved by giving consideration to the issues of regional homogeneity and/or heteroskedasticity across the research area. With respect to estimation, specific attention should be paid to the selection of the appropriate strategy in terms of the auxiliary regression model. The paper shows that by testing for heteroskedasticity, and by using robust methods in the presence of with and without heteroskedasticity, more efficient statistical inferences are provided.

• Journal of the Korean Home Economics Association
• /
• v.37 no.10
• /
• pp.91-106
• /
• 1999

The purpose of this study is to analyze empirically the influences of different types of household income and asset in the consumption expenditures of homeowners and lessees with deposit. The data used in this study were the 1996 Korea Household Panel Study. 1,512 households data were selected for the final analysis. The statistical methods adopted for data analysis were frequency, percentage, one-way ANOVA, crosstabs, multiple regression analysis, and chow-test. The results are as follows: (1) There were the differences between three groups in the expenditure levels of each consumption category and the shares of each consumption category of total expenditures. (2) The change of labor income influenced more significantly consumption expenditures of homeowners and lessees with deposit, compared to changes of different types of household income. Also homeowners and lessees with deposit changed their consumption expenditures in different ways to changes of various types of household income. (3) Homeowners increased more significantly their consumption expenditures to increase of net asset than lessees with deposit.

• International Journal of High-Rise Buildings
• /
• v.6 no.3
• /
• pp.237-248
• /
• 2017

China's rapid growth has created great opportunities for design and construction of projects that not only transform sites but cities. This work combines local, national, and international expertise in developing memorable designs that seek to humanize urban life and emphasize the importance of visionary clients. Innovative examples of work in China will be presented with emphasis on three iconic projects designed and built for Poly Corporation based in China. These projects include developments in Beijing and Guangzhou and introduce the use of locally supplied materials and construction techniques. The Poly Corporate Headquarters, the Poly Real Estate Headquarters, and the Poly International Plaza, and will be described through innovative ideas that integrate urban planning, structure, and architecture.

• Communications for Statistical Applications and Methods
• /
• v.22 no.6
• /
• pp.605-613
• /
• 2015

A three-arm parallel design has been proposed to assess the biosimilarity between a biological product and a reference product using relative distance (Kang and Chow, 2013). The three-arm parallel design consists of two arms for the reference product and one arm for the biosimilar product. This paper extended the three-arm parallel design to a (k + 1)-arm parallel design composed of k (${\geq}3$) arms for the reference product and one arm for the biosimilar product. A new relative distance was defined based on Euclidean distance; consequently, a corresponding test procedure was developed based on asymptotic distribution. Type I error rates and powers were investigated both theoretically and empirically.

• 한국방재학회:학술대회논문집
• /
• 2007.02a
• /
• pp.628-631
• /
• 2007

One of the structural measures for the peak flow reduction is infiltration facilities. There are many types in infiltration facilities - infiltration basin, trench, bed, porous pavement, percolated subdrain, dry well. In this study runoff reduction effect of infiltration trench is analyzed by WinSLAMM. Runoff reduction effect is investigated by each design rainfall and temporal pattern of rainfall particularly. The biggest reduction is shown in Yen and Chow's temporal pattern of design rainfall and the smallest reduction is shown in Huff's first quartile pattern. Runoff reduction rate is presented about 6 to 14 percentage, and the larger return period, the smaller runoff reduction rate.

• Journal of Life Science
• /
• v.10 no.5
• /
• pp.467-474
• /
• 2000

Male mice (ddY strain) were fed a laboratory chow diet containing the water extract from stem bark of Rhus verniciflua Stokes (RVS) for 14 days. There were no significant difference in body weight gain, feed intake, the hepatic lipid profile and serum total cholesterol and phodpholipid concentrations. The concentration of triglyceride in serum was significantly lower in the RVS group than that in the control group. The concentration of high-density-lipoprotein cholestrol in serum was significantly higher in the RVS group than that in the control group. The methanol extract from RVS stem bark effectively inhibited the formation of thiobarbituric acid-reactive substances as a marker of lipid peroxidation of liver microsomes in a concentration-dependent manner. This study showed that the water extract from stem bark of RVS decreased the serum triglyceride concentration and methanol extract has an antioxidative activity.

• Journal of Trauma and Injury
• /
• v.33 no.1
• /
• pp.43-47
• /
• 2020

Pancreatic and gastric fistulas are rare complications of emergency splenectomy, and it is extremely rare for a pancreatic fistula to be further complicated by a fistulation into the stomach. Here, we present a case of pancreatogastric fistula in a 60-year-old man who experienced polytrauma due to a blunt mechanism. He underwent emergency splenectomy for splenic injury and developed a pancreatic fistula as a complication. A percutaneous endoscopic procedure was performed to drain the fistula, after which he developed a pancreatogastric fistula as a further complication. A double-pigtail stent was inserted via gastroscopy into the fistula tract to allow internal drainage of the pancreatic collection into the stomach cavity. When a pancreatic fistula is complicated by gastric fistulation, endoscopic stenting of the pancreatogastric fistula tract for internal drainage is an effective treatment option.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.1108-1112
• /
• 2005

보(round-crested weir)는 수로나 하천의 수위를 조절 과 취수 등의 편의를 제공하기 위해 건설되는 하천 구조물이다. 일반적으로 보의 수리특성은 자유 월류라는 측면에서 댐의 여수로와 유사하지만 하류 수위가 높아져 수중(submerged)에 잠기게 되면 보의 수리 특성은 여수로와 다르게 해석하여야 한다. 기존의 연구에서는 하류수위조건에 따라 4가지의 경우 1) 사류, 2) 도수현상을 수반한 상류, 3) 사류흐름으로 인한 도수발생, 4) 잠김상태(submerged)로 구분하고 있다(Chow ,1952). 그러나 이에 대한 흐름 해석은 대표적인 보에 대해 제안된 식으로 각 경우에 대한 정확해 해석은 어려움이 있다. 특히 하천에 수문과 동시에 보가 설치될 경우 그 차이는 클 것으로 판단된다. 본 연구에서는 하천에 설치되는 보와 수문에 대한 실험연구로써 보의 높이에 비해 수위가 과다하게 높은 경우에서의 수위-유량관계를 이론식과 기존 웨어공식에 대해 각각 비교하여 그에 대한 차이를 검토하였으며 하류수위에 대한 상류수위변동 시점을 측정하여 하류수위의 영향을 받는 임계수심을 제안한 Knapp(1960)식과 비교하였다.

• Communications for Statistical Applications and Methods
• /
• v.7 no.2
• /
• pp.541-548
• /
• 2000

Various statistical methods for assessment of equivalence in average bioavailabilities have been developed under the assumption that the intra-subject variabilities for the test and reference formulations are the same. Without the assumption, assessing the equivalence in average bioavailabilites does not imply that the two formulations are therapeutically equivalent and exchangeable. The most commonly used test procedure for equality of variabilites in 2$\times$2 crossover experiment is the so called Pitman-Morgan's adjusted F test based on the model without carryover effects (Chow and Liu(1992)). In this paper, a Bayesian method based on the Intrinsic Bayes Factor is proposed, which can be applied to the model with carryover effects.

• Communications for Statistical Applications and Methods
• /
• v.10 no.3
• /
• pp.1069-1086
• /
• 2003

This article presents the asymptotic theory of triple sampling procedure as pertain to estimating the shape parameter of Pareto distribution. Both point and confidence interval estimation are considered within the same inference unified framework. We show that this group sampling technique possesses the efficiency of Anscome (1953), Chow and Robbins (1965) purely sequential procedure as well as reduce the number of sampling operations by utilizing Stein (1945) two stages procedure. The analysis reveals that the technique performs excellent as far as the accuracy is concerned. The present problem differs from those considered by many authors, in multistage sampling, in that the final stage sample size and the parameter's estimate become highly correlated and therefore we adopted different approach.