• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.862-870
• /
• 2010

This thesis has been researched on optimized design method for the total cross section of embankment considering the fact that the size of embankment cross section is directly related with economic efficiency when dam designing. In general, embankment cross section of fill dam is either determined by cohesion and angle of internal friction, a strength parameter of embankment materials or by permeability of embankment. Therefore the size of embankment cross section depending on strength parameter of embankment materials was determined by using MIDAS-GTS program through stress-seepage coupled analysis at the time of fill dam design. As a result, determination of embankment cross section was more affected by the size of central core and permeability rather than by slope stability by shear strength and it was revealed that in case of embankment height being over 20m, stability against infiltration and slope action could be secured only when embankment slope is at least over 1:2.5. In addition, it was also revealed that in case of making the size of central core exceeding specification standard, total cross section of embankment could be reduced considerably and at the time of embankment design, adequate size and appropriateness of embankment cross section could be determined with referring the table suggested by this study.

• Geomechanics and Engineering
• /
• v.20 no.6
• /
• pp.497-503
• /
• 2020

In the Kingdom of Saudi Arabia, the shallower depth of the earth's crust is composed of loose dune or beach sand with soluble salts. The expansive behavior of salt bearing soil, fluctuation of ground water table and extreme environmental conditions offer a variety of geotechnical problems affecting safety and serviceability of the infrastructure built on it. Despite spending money, time and other resources on repair and rehabilitation, no significant attention is paid to explore the root causes of excessive differential settlement and cracking to these facilities. The scientific solution required to ensure safety and serviceability of the constructed infrastructure is to improve the strength and durability properties of the supporting ground. In this study, shredded plastic is employed as a low cost and locally available additive to improve strength characteristics of the desert sand. The study shows a remarkable increase in the shear strength and normal settlement of the soil. A seven (07) degree increase in angle of internal friction is achieved by adding 0.4 percent of the shredded plastic additive. The effect of different proportions and sizes of the plastic strips is also investigated to obtain optimum values. Such a long-lived solution will seek to reduce maintenance and repair costs of the infrastructure facilities laid on problematic soil along with reduction of environmental pollutants.

• The Korean Journal of Nuclear Medicine
• /
• v.3 no.1
• /
• pp.59-67
• /
• 1969

Correlation between the blood clearance half time and findings of liver scan using the colloidal radiogold in patients of liver cirrhosis is observed through the scoring system, in which the more changes in size, shape and density in the liver scan, the more points are given (table 1). Results: 1) Within the increase in severity of hepatocellular dysfunction in liver cirrhosis, the degree and frequency of following changes in liver scan (done with colloidal radiogold) were increased in order. a) generalized hepatomegaly b) enlargement of the left lobe & reduction of the right lobe c) relatively increased radiodensity in the left lobe and 4) visualization of spleen. 2) Frequency of the normal scan in liver cirrhosis was $12{\pm}3.56%$, frequency of normal value in blood clearance half time of the radiogold was $5.0{\pm}2.34%$ and frequency of normal scan & normal blood clearance rate in liver cirrhosis was $3.6{\pm}2.06%$.

• 한국해양학회지
• /
• v.28 no.1
• /
• pp.17-23
• /
• 1993

A right cylindrical tank with sloping bottom and top (${\beta}-effect$) is filled with two-layered fluid and is put on the rotating table. External fluid of same density as the lower-layer fluid is continuously injected to drive the lower-layer current. By minimizing the interfacial stress between two layers the motion in the lower-layer deformed the shape of interface such that the upper-layer adjust itself to the variations of the interface in terms of its direction of flow patterns .The most significant parameter is the internal Froude Number($F_1$) and when $F_1$ is greater than 6 two-cellular circulation of the upper-layer changes its direction, there by creates a separation of Western boundary current. The separation position moves to the most northward when $F_1$ equals to 6.

• Korean Journal of Computational Design and Engineering
• /
• v.11 no.5
• /
• pp.327-334
• /
• 2006

Recently, security incidents are growing rapidly in which internal employees let the drawing leak out to competitors or other countries. This type of security incidents has a characteristic that it occurs less frequently than other types of security incidents such as network or server security incident, but the damage is a lot more serious. The existing information security technologies to prevent internal information from being leaked out are only applicable to general documents(office documents, web pages and image files in which data are encrypted one by one). However, architectural drawings made up of collection of files with various formats(extensions) have problems with the process speed of en(de) cryption and accuracy, so the developments of security technologies by new methods are required. In this study, we design and develop a security technology based on work area with which users can protect the leakage of critical information in the kernel level while maintaining their work environment when they have to use sharing information that cannot be managed by the unit of file. As a result, we developed the "Virtual Secure Disk" which allows only authorized users and applications to have an access to drawings, and have verified its security by applying it to the actual company.

• Geomechanics and Engineering
• /
• v.19 no.2
• /
• pp.179-191
• /
• 2019

Based on the effective stress principle, a new formula for shear strength of unsaturated soil is derived under the general nonlinear Mohr-Coulomb (M-C) strength criterion to improve the classical strength criterion of unsaturated soil. Meanwhile, the simple irrigation model under steady seepage is adopted to obtain the distribution of the matrix suction or the degree of saturation (DOS) above the groundwater table in the slope. Then, combined with the improved strength criterion of unsaturated soil and the simple irrigation model under steady seepage, the limit equilibrium (LE) solutions for the unsaturated slope stability are established according to the global LE conditions of the entire sliding body with assumption of the stresses on the slip surface. Compared to the classical strength criterion of unsaturated soil, not only the cohesion soil but also the internal friction angle is affected by the matric suction or the DOS in the improved strength criterion. Moreover, the internal friction angle related to the matric suction has the nonlinear characteristics, particularly for a small of the matric suction. Thereafter, the feasibility of the present method is verified by comparison and analysis on some slope examples. Furthermore, stability charts are also drawn to quickly analyze the unsaturated slope stability.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.1
• /
• pp.295-304
• /
• 2021

This study aims to identify and analyze the impact of internal factors on business efficiency of steel firms in Vietnam. The article uses data collected from the financial statements of 26 steel firms operating in Vietnam between 2012 and 2019. With the application of E-view software in quantitative analysis to build regression models on the table data (panel data), and the study has built a regression model identifying the relationship and impact level of internal factors affecting business efficiency of steel firms in Vietnam. In the study, the dependent variable is business efficiency, determined by the profit after tax on the firm's assets. The independent variables are firm size, growth rate, capital structure, ratio of long-term assets, receivables management, and solvency. The research results show that the four factors of firm size, growth rate of assets, receivables management, and solvency have a positive impact on business efficiency, while two factors including capital structure and ratio of long-term assets do not affect business efficiency of enterprises. The results of this article are very useful for corporate executives in general and for financial managers in particular, helping managers make the right financial decisions for the company to promote business efficiency of the company.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.3
• /
• pp.391-396
• /
• 1994

Carcinoembryonic Antigen is one of most frequently checked tumor markers in cancer management. We performed statistical analysis with serum CEA data of 2626 persons who received regular health examination and were thought to be free of active disease to determine the cutoff values of serum CEA level in normal Korean adults and to study the factors influencing serum CEA levels in normal subjects. 1) The cutoff values of serum CEA in normal Korean adults in general were 9.28ng/ml for men, 5.90 ng/ml for women. 2) Serum CEA level was influenced by age, present smoking history, sex, and abnormal findings in chest X ray. 3) Serum CEA level had no correlation with the history of amount of alcohol consumption or obesity. 4) Cutoff values of serum CEA in normal Korean adults were tabulated according to age, sex, and smoking history. Serum CEA level was influenced by age, sex, present smoking history and abnormal findings in chest X ray and cutoff values of serum CEA were tabulated according to age, sex, and smoking history.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.1
• /
• pp.50-56
• /
• 2017

The IRR (internal rate of return) is often used by investors for the evaluation of engineering projects. Unfortunately, it is widely known that it has serial flaws. Also, External rate of returns (ERRs) such as ARR (Average Rate of Return) or MIRR (MIRR, Modified Internal Rate of Return) do not differentiate between the real investment and the expenditure. The PRR (Productive rate of return) is faithful to the conception of the return on investment. The PRR uses the effective investment instead of the initial investment. In this paper, we examined two cases of the engineering project. the one is a traditional engineering project with financing activity, another is the project with R&D. Although the IRR has only one value, it overestimates or underestimate profitabilities of Engineering Projects. The ARR and the MARR assume that a returned cash reinvest other projects or assets instead of the project currently executing. Thus they are only one value of a project's profitability, unlike the IRR. But the ARR does not classify into the effective investment and non-investment expenditure. It only accepts an initial expenditure as for an investment. The MIRR also fails to classify into the investment and the expenditure. It has an error of making a loss down as the investment. The IRR works as efficiently as a NPW (Net Present Worth). It clearly expresses a rate of return in respect of an investment in an engineering project with a loan. And it shows its ability in an engineering project with a R&D investment.

• Journal of International Academy of Physical Therapy Research
• /
• v.2 no.1
• /
• pp.229-236
• /
• 2011

The purpose of this study was to comparatively analyze the active stability of shoulder joints according to the frequency of overhead motions, such as serving and spiking, engaged in by female professional volleyball athletes who play different positions, and to provide the results as the basic data for developing exercise programs to prevent shoulder joint injuries. The subjects of this study were 50 Korean female professional volleyball players and positions were as follows: left and right attackers, centers, setters, and liberos. The external rotation and internal rotation muscle strength and muscle strength ratios of the dominant and non-dominant arms of all subjects were measured using Biodex. The results of this study are as follows: Frist, no significant differences were found in the internal and external rotation muscle strength of the dominant and non-dominant arms between positions. Second, for the shoulder joint muscle strength ratio of the dominant arm, by position, the setter showed significantly greater stability compared to the other positions. Third, for the shoulder joint muscle strength ratio of the non-dominant arm, by position, no significant difference in stability between positions was found. Fourth, it was found that the dominant arm had significantly greater instability of the shoulder joint than the non-dominant arm for attackers and centers, but no significant difference was found for setters and liberos. This study comparatively analyzed the muscle strength ratios of the external/internal rotations and dominant/non-dominant arms, which can determine the stability of the shoulder joints between female professional volleyball playing positions that engage in jumps and spikes using only the dominant hand and positions that do not.