• Journal of Mechanical Science and Technology
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• v.14 no.7
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• pp.789-795
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• 2000

Free-surface flows with an arbitrary deformation, induced by a submerged hydrofoil, are simulated numerically, considering two-fluid flows of both water and air. The computation is performed by a finite volume method using unstructured meshes and an interface capturing scheme to determine the shape of the free surface. The method uses control volumes with an arbitrary number of faces and allows cell wise local mesh refinement. The integration in space is of second order, based on midpoint rule integration and linear interpolation. The method is fully implicit and uses quadratic interpolation in time through three time levels. The linear equations are solved by conjugate gradient type solvers, and the non-linearity of equations is accounted for through Picard iterations. The solution method is of pressure-correction type and solves sequentially the linearized momentum equations, the continuity equation, the conservation equation of one species, and the equations for two turbulence quantities. Finally, a comparison is quantitatively made at the same speed between the computation and experiment in which the grid sensitivity is numerically checked.

• Journal of the Korea Computer Graphics Society
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• v.19 no.1
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• pp.1-9
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• 2013

Color plays a fundamental and important role in various areas, it has become important to choose colors which fits the purpose and also harmonious. The goal of this study is to reduce the difficulties of choosing the color and get the colors with high satisfaction when users want to choose multiple colors. To do this, we extracted and analysed a large number of colors in color database. And We designed an interface applied to high preference color combination rule. We also evaluated the usability and user satisfaction of the interface. The results showed that the functionality of the developed interface is more useful and is more satisfied than that of the conventional interface.

• Journal of KIISE:Software and Applications
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• v.28 no.10
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• pp.732-742
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• 2001

The concept of an agent has become important in computer science and has been applied to the number of application domains such electronic commerce and information retrieval. But, no one has proposed yet in software test. The test agent system applied the concept of an agent to software test is new test tool. It consists of the User Interface Agent. the Test Case Selection & Testing Agent and the Regression Test Agent. Each of these agents, with their intelligent rules, carry out the tests autonomously by empolying the object-oriented test processes. This system has 2 advantages. Firstly since the tests are carried our autonomously, it minimizes tester interference and secondly, since redundant-free and consistent effective test cases are intellectually selected, the testing time is reduced while the fault detection effectiveness improves. In this paper, by actually showing the testing process being carried out autonomously by the 3 agents that form the TAS, we show that the TAS minimizes tester interference. By also carrying out the 4 different types of experiments on the RE-Rule, CTS-Rule, overall TAS experiment, and the fault-detection effectiveness experiment on the RE-Rule, we show the cut-down on the testing time and improvement in the fault detection effectivity.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.57-70
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• 1999

Since a hybrid firewall filters packets at a network layer along with providing gateway functionalities at an application layer, it has a better performance than an If filtering firewall. In addition, it provides both the various kinds of access control mechanisms and transparent services to users. However, the security policies of a network layer are different from those of an application layer. Thus, the user interfaces for managing a hybrid firewalls in a consistent manner are needed. In this paper, we implement a graphical user interface to provide access control mechanisms and management facilities for a hybrid firewall such as log analysis, a real-time monitor for network traffics, and the statisics on traffics. And we also propose a new rule script language for specifying access control rules. By using the script language, users can generate the various forma of access control rules which are adapted by the existing firewalls.

• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.186-195
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• 2016

The finite element modeling of a ship for hull structural analysis on the basis of new harmonized common structural rules (CSR-H) is to be extended to the cargo holds in fore and after body of a ship. Unlike the parallel middle-body where the external and internal features of hull are equal along to the longitudinal direction of a ship, in fore and after body, the external and internal features of hull vary linearly or even irregularly in forms of a surface or a curve along to the longitudinal direction of a ship. Thus, it needs lots of design man-hours for the modeling for structural analysis. In order to save man-hours in initial structural design phase of a ship, the specified 3D CAD system has been adopted in shipbuilding industry. Through the interface between CAD and CAE (rule scantling and direct strength assessment), design man-hour in initial design phase can be saved even under the environment of CSR-H.

• Coupled systems mechanics
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• v.8 no.1
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• pp.71-93
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• 2019

Finite element simulations of solid mechanics problems often involve the use of Non-Confirming Meshes (NCM) to increase accuracy in capturing nonlinear behavior, including damage and plasticity, in part of a solid domain without an undue increase in computational costs. In the presence of material nonlinearity and plasticity, higher-order variables are often needed to capture nonlinear behavior and material history on non-conforming interfaces. The most popular formulations for coupling non-conforming meshes are dual methods that involve the interpolation of a traction field on the interface. These methods are subject to the Ladyzhenskaya-Babuska-Brezzi (LBB) stability condition, and are therefore limited in their implementation with the higher-order elements needed to capture nonlinear material behavior. Alternatively, the enriched discontinuous Galerkin approach (EDGA) (Haikal and Hjelmstad 2010) is a primal method that provides higher order kinematic fields on the interface, and in which interface tractions are computed from local finite element estimates, therefore facilitating its implementation with nonlinear material models. The inclusion of higher-order interface variables, however, presents the issue of preserving material history at integration points when a increase in integration order is needed. In this study, the enriched discontinuous Galerkin approach (EDGA) is extended to the case of small-deformation plasticity. An interface-driven Gauss-Kronrod integration rule is proposed to enable adaptive enrichment on the interface while preserving history-dependent material data at existing integration points. The method is implemented using classical J2 plasticity theory as well as the pressure-dependent Drucker-Prager material model. We show that an efficient treatment of interface variables can improve algorithmic performance and provide a consistent approach for coupling non-conforming meshes in inelasticity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.82-85
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• 1992

In this study, charge pumping method was used to investigate the Si-SiO$_2$interface characteristics of the nonvolatile SNOSFET memory devices, fabricated using the CMOS 1 Mbit processes (1.2$\mu\textrm{m}$ design rule), with thin oxide layer of 30${\AA}$ thick and nitride layer of 525${\AA}$ thick on the n-type silicon substrate (p-channel). Charge pumping current characteristics with the pulse base level were measured for various frequencies, falling times and rising times. By means of the charge dynamics in a non-steady state, the average Si-SiO$_2$interface state density and capture cross section were determined to be 3.565${\times}$10$\^$11/cm$\^$-2/eV$\^$-1/ and 4.834${\times}$10$\^$-16/$\textrm{cm}^2$, respectively. However Si-SiO$_2$ interface state densities were disributed 2.8${\times}$10$\^$-11/～5.6${\times}$10$\^$11/cm$\^$-2/～6${\times}$10$\^$11/cm$\^$-2/eV$\^$-1/ in the lover half of energy gap.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.173-179
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• 2000

The influence of the plastic flow rules on the elasto-plastic behaviour of a discrete joint element was investigated by performing the numerical direct shear tests under both constant normal displacement and normal displacement conditions. The finite interface elements obeying Plesha’s joint constitutive law was used to allow the relative motion of the rock blocks on the joint surface. Realistic results were obtained in the tests adopting the non-associated flow rule, while the associated flow rule overestimated the joint dilation. To overcome the computational drawbacks coming from the non-symmetric element stiffness matrix in the conventional non-associated plasticity, the symmetric formulation of the tangential stiffness matrix for a non-associated joint element was proposed. The symmetric elasto-plastic matrix it derived by assuming an imaginary equivalent joint with associated flow rule which shows the same plastic response as that of original Joint with non-associated flow rule. The validity of the formulation was confirmed through the numerical direct shear tests under constant normal stress condition.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.358-362
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• 1991

This paper describes enhancements made on PROSET, an, expert system which can perform setting and coordination of protective relays used in the ultra-high voltage transmission systems. Enhancements include the friendly and convenient environment for rulebase management and system manipulation, expanded setting capability, and faster processing speed which have been achieved through adoption of the new rule representation, rule order independent IE, rulebase editor, local database generator, Interface to PSS/E fault program, RB expansion etc.

• Journal of the Korean Data and Information Science Society
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• v.18 no.4
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• pp.1157-1170
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• 2007

LBS must manage various context data and make the best use of this data for application service in ubiquitous environment. Conventional mobile object data management architecture did not consider process of context data. Therefore a new mobile data management framework is needed to process location context data. In this paper, we design a new context management framework for a location based application service. A suggestion framework is consisted of context collector, context manager, rule base, inference engine, and mobile object context database. It describes a form of rule base and a movement process of inference engine that are based on location based application scenario. It also presents an embodiment instance of interface which suggested framework is applied to location context interference of mobile object.