• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.1
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• pp.95-104
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• 2003

This paper deals with the analytic and FEM analyses of sloshing frequency response of incompressible, invicid and irrotational flow in two dimensional rectangular tank. We use Laplace equation based on potential theory as governing equation. For small amplitude sloshing motion, the linearized free surface condition was applied and the analytic solution as obtained by the separation of variables. To simulate the effect of the energy dissipation due to viscous damping, artificial viscous coefficient is introduced and the divergence of response at resonance frequencies may be avoided by this coefficient. This problem was solved by FEM using 9-node elements in order to predict the maximum amplitude of sloshing response. Numerical results of free surface height, fluid pressure and fluid force show good agreement with those by analytic solution. After verifying the test FEM program, we analyze the frequency response characteristics of sloshing to the fluid height.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.503-509
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• 2014

In this study, a new concept perforated breakwater is proposed, which is having resonant channels. In the channel, perforated plate is installed for dissipating wave energy induced by flow separations. The breakwater has two advantages compared with conventional perforated breakwater having wave chamber with slotted walls. One is easy to control the target wave condition for dissipating wave energy, and the other is having the high structural safety because the structural members are not exposed to impact waves, directly. To evaluate wave reflection characteristics of the proposed breakwater, numerical experiment was carried out by using Galerkin's finite element model based on the linear potential theory. The results indicated that considerable energy dissipation occurs near the resonant period of channel, and wave reflection characteristics are affected by channel shape, location and opening ratio.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.483-494
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• 2023

Measurement of the physical properties of rocks or minerals is an important factor in determining the distribution of the underground medium as well as mineral resource investigations. Resistivity and induced polarization, which are widely used in Korea, are methods for measuring electrical properties, which are representative properties of obtaining subsurface information. In order to precisely analyze the exploration data obtained from various sites, it is important to accurately measure the material properties. Electrical properties of rock is measured using two-electrode or four-electrode method. Compared to the four-electrode method, the two-electrode method is generally used because it is very easy to contact the sample and the electrode, but there is a problem in that the impedance of the electrode and the sample is measured together. In this study, the time-domain the induced polarization effects were measured using the 2-electrode method and the 4-electrode method for artificial samples mixed with graphite and cement having induced polarization characteristics, and the results were compared. Although the 4-electrode method has difficulties in installing potential electrodes, it was confirmed that it is effective in measuring electrical properties because it can reduce the problem caused by the impedance of potential electrodes compared to the 2-electrode method.

• Water for future
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• v.13 no.2
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• pp.35-47
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• 1980

An algorithm is developed to derive a representative I hr-unit hydrograph through an analysis of rainfall-runoff relations of a watershed as a closed system. For the base flow seperation of a flood hydrograph the multi-deflection method is proposed herein, which gace better results compared with those by the existing empirical methods. A modified $\Phi$index method is also proposed in this stidy to determine the time distribution rainfall excess of a rainstorm, which is essetially a modification of the commonly used $\Phi$index method of rainfall seperation. With the so-obtained rainfall excess hyetograph and the direct runoff hydrograph a trial and error computation of the ordinates of 1 hr-unit hydrograph was executed in such a manner that the synthesized flood hydrograph closely approximates the observed one, thus resulting a unit hydrograph of a piecewise exponential function type. To verify the validity of this study the 1 hr-unit hydrographs for the Imha and Dongchon in Nagdong River basin, and Yongdam in Geum River basin were derived by this algorithm, and the results were compared with those by the conventional synthetic unit hydrograph method and the Nakayasu method. Besides, the validity of this stiudy was also tested by comparing the observed hydrograph with the one computed by applying the unit hydrograph to a specific rainfall event. To generalize the result of this study a computer program, consisited of a main and three subprograns (for rainfall excess estimation, convolution summation, and sorting), is developed as a package, which is believed to be applicable to other watersheds for the similar purpose as those in this study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.9
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• pp.597-604
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• 2016

A parallel algorithm of bi-conjugate gradient method was developed based on CUDA for parallel computation of the incompressible Navier-Stokes equations. The governing equations were discretized using splitting P2P1 finite element method. Asymmetric stenotic flow problem was solved to validate the proposed algorithm, and then the parallel performance of the GPU was examined by measuring the elapsed times. Further, the GPU performance for sparse matrix-vector multiplication was also investigated with a matrix of fluid-structure interaction problem. A kernel was generated to simultaneously compute the inner product of each row of sparse matrix and a vector. In addition, the kernel was optimized to improve the performance by using both parallel reduction and memory coalescing. In the kernel construction, the effect of warp on the parallel performance of the present CUDA was also examined. The present GPU computation was more than 7 times faster than the single CPU by double precision.

• Journal of Korean Philosophical Society
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• no.85
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• pp.53-76
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• 2009

Plato's Laws, Bk. 10 is made up of cryptically concise expressions and complex arguments, so that it is not simple to understand it. In this essay I would like to make use of Stoic perspective as an interpretative instrument, which would enable me, I hope, to reconstruct the main arguments of the Laws, Bk. 10 into an intelligible form. Through this approach we would have an opportunity to meet with some important philosophical ideas of Plato which did not reveal themselves clearly in other, especially early and middle dialogues. These ideas comprise the inseparability of the soul from the body, the intellectualization of nature, the human being as a part of the cosmos and the extensional overlapping of the moral law and the natural law. And at the same time my study would result in making a suggestion for history of reception. That is, in this paper I will find some grounds in the tenth book of the Laws that would show how great the influence of Plato upon the Stoics was. For we have but little knowledge about the possibility of the power of Plato's influence upon the Stoics, even though the scholarship on the Stoics until now shed some light on the features and range of Aristotle's influence upon them.

• Journal of Sinology and China Studies
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• v.81
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• pp.227-256
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• 2019

Hong Kong's protests, which began in June 2019 with Anti-Extradition Bill Protests, have already lasted for months, and the demonstrations have a significant impact on China and Hong Kong as a whole. The protests began in opposition to the Hong Kong government's revision of the extradition bill, but in substance, it has a strong nature as a test of China's "One Country Two Systems" policy. Since the establishment of the Hong Kong Special Administrative District on July 1, 1997, the primary legal norm between China and Hong Kong is the Basic Law of Hong Kong. However, conflicts of legal standards have occurred frequently due to the difference between socialism and the capitalist legal system, and there has been a continuous controversy over the interpretation of the Basic Law of Hong Kong. Moreover, the core of the legal conflict between China and Hong Kong has always been China's "One Country Two Systems" policy. This paper examined the issues related to the "Right of Legal Interpretation" of Standing Committee of the National People's Congress, the characteristics and interpretation rights of the Basic Law of Hong Kong, the direct election system of the administrative minister, the implementation of the universal suffrage, and the legislative issues of the application of Article 23 of the Hong Kong Basic Law. Furthermore, this paper also investigated the laws and systems newly introduced by China to solve these legal conflicts. The integration of the legal system of the divided state is a complicated process beyond the combination of the legal system by integrating the multiple legal systems that have separated for a long time under heterogeneous political, economic, and social networks. Moreover, the adjustment and integration of various legal systems under the premise of a single Constitution is the starting point for the actual inclusion of various fields after the unification as well as unification process and provides a basis for achieving full integration. Therefore, the unification of the divided countries should be the first step in a long journey toward becoming a practical one, not a goal itself. It is crucial to reduce trial and error and cost, and achieve stable unification in our unification process in Korea, by learning lessons from the contradictions and conflicts that appear in the "One Country Two Systems" unification between China and Hong Kong.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.348-355
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• 1985

Extended Huckel Calculation of cis-and trans-dichloro diammine platinum(II), dichloroethylene diamine platinum(II) and their N-mono, di, tri and tetra-methylated or ethylated ones were carried out to investigate their anticancer activity. It was found that the net charge of two chlorine atoms in cis-isomers are greater than those in trans-ones and Pt-Cl bond energies of the former are less than that of the latter, indicating that Pt-Cl bond in cis-isomers has greater ionic character than that in trans-ones and Cl atoms in the former are easier to dissociated as Cl- than those in the latter. Also, the values of $b_{2g}-b_{1g}$ energy difference, ${\Delta}_1$ were found to be greater in cis-isomers than in trans-one without exceptions. For the substitution of methyl for H atom in ammine and ethylenediamine Pt-Cl bond strength shows the tendency to increase with increasing in number of methyl group. Accordingly, We believe that two Cl atoms in $PtLCl_2$-complexes (L: NH$_3$, en) are dissociated in the first step of the action of anticancer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.302-304
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• 2015

Waters that are under surveillance for traffic safety designated area due to increased risk of ship accidents are usually areas in the coastal waters specified by the government. However, there are still some controversies surrounding application of navigation rule in regards to these waters. Such law is especially difficult to apply to VTSO access sea route within Kwangyang bay area. Therefore, as a solution for the issues discussed in this research, the goal is to help establish a unified application method for navigation rule in relation to VTS areas, to improve marine traffic safety by separating and applying specific laws from marine safety law, and to provide a ground on which the VTSO can take a proactive and focused approach in performing monitoring duties.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.202-205
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• 2001

The root of Zingiber officinale R. was extracted with 80% aqueous MeOH, and the concentrated extract was fractionated with EtOAc, n-BuOH and water phases. The EtOAc fraction exhibited most potent antioxidant activity among them, and two active compounds were isolated by activity-guided separation using repetitive silica gel column chromatography. On the bases of spectral data and the chemical characteristics, the structure of the compounds were determined as 6-shogaol and 12-shogaol, respectively. The $EC_{50}$ values of them were evaluated as 26.4 ${\mu}M$ and 22.5 ${\mu}M$, respectively, where these values were higher than the commercial antioxidants, such as, BHA, BHT and ${\alpha}-tocopherol$.