• Geophysics and Geophysical Exploration
• /
• v.8 no.3
• /
• pp.207-217
• /
• 2005

We present a new approximate formulation of the integral equation (IE) method for models with variable background conductivity. This method overcomes the standard limitation of the conventional If method related to the use of a horizontally layered background only. The new approximate IE method still employs the Green's functions for a horizontally layered 1-D model. However, the new method allows us to use an inhomogeneous background with the IE method. The method was carefully tested for modeling the EM field for complex structures with a known variable background conductivity. It can find wide application in modeling EM data for multiple geological models with some common geoelectrical features, like a known inhomogeneous overburden, or salt dome structures.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.510-516
• /
• 2005

This research aims to verify the stress distribution in soil according to the composition of the soil layer in case of surface loading. For this purpose, loading tests with measurement of stresses in the soil on four kinds of layered model ground in laboratory were performed. Those are (1)homogeneous sand, (2)gravel underlain by sand, (3)sand underlain by clay and (4)gravel underlain by clay. Test results are compared and analysed for the compositions of the soil layers. based on the results obtained, it is found that the larger the difference of the strengths of upper and lower layer is, the smaller the stress in the soil in case of surface loading is.

• Management Science and Financial Engineering
• /
• v.3 no.2
• /
• pp.71-92
• /
• 1997

Developing FMS controllers has been a difficult problem largely because of the variety of the system configuration. The purpose of this paper is to develop a method of building an FMS controller. The controller consists of control module and execution module. A hierarchically layered structure of these modules is proposed. The control module generates abstract-level execution requested by identifying a set of activities that can be executed without creating any irregular state. The execution module transmits the requests to physical device controllers and reports back the completion of the requests to the control module. Both of these two modules use Petri Net-based models. In this paper, a controllable Petri Net model is automatically synthesized from declarative specifications provided by a user. An execution Petri Net model for the execution module is designed to ensure the consistency between the control module and the real target system. The controller operates in MMS on TCP/IP and UNIX environment.

• The Journal of Engineering Geology
• /
• v.6 no.3
• /
• pp.119-130
• /
• 1996

The theory and numerical technique using boundary elements method (BEM) are given to solve 2-dimensional resistivity problems. Potential distributions from homogeneous resistivity model and layered model are calculated by using BEM for a point source of current injection. The potential distributions of BEM are compared with those of finite difference method (FDM) and finite elements method (FEM). Among the three numerical methods to solve 2-dimensional resistivity problem, it is proved that BEM is more efficient tool than FDM and FEM in consideration of computing storage and time as weU as the accuracy of solutions.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.10 no.3
• /
• pp.120-128
• /
• 2007

In order to reduce the lead-time and cost, the technology of rapid prototyping(RP) has been widely used. This paper describes the methodology to fabricate a large object by using the principle of rapid prototyping. By laminating thick and sloping polystyrene foam plates, we can make the large model which has three dimensional, continuous surfaces faster and easier than conventional processes. Estimated error was much smaller than other RP products which have stepped effect. For accuracy improvement and post processing, machined metal plates are added between the thick plates. To keep the continuity of surface and strengthen the model, pilot holes and guide rods are applied. By the methodology described in this paper, a missile body with flush air intake was fabricated.

• Geophysics and Geophysical Exploration
• /
• v.5 no.4
• /
• pp.280-290
• /
• 2002

Three-dimensional (3-D) electromagnetic (EM) modeling algorithm has been developed using finite element method (FEM) to acquire more efficient interpretation techniques of EM data. When FEM based on nodal elements is applied to EM problem, spurious solutions, so called 'vector parasite', are occurred due to the discontinuity of normal electric fields and may lead the completely erroneous results. Among the methods curing the spurious problem, this study adopts vector element of which basis function has the amplitude and direction. To reduce computational cost and required core memory, complex bi-conjugate gradient (CBCG) method is applied to solving complex symmetric matrix of FEM and point Jacobi method is used to accelerate convergence rate. To verify the developed 3-D EM modeling algorithm, its electric and magnetic field for a layered-earth model are compared with those of layered-earth solution. As we expected, the vector based FEM developed in this study does not cause ny vector parasite problem, while conventional nodal based FEM causes lots of errors due to the discontinuity of field variables. For testing the applicability to high frequencies 100 MHz is used as an operating frequency for the layer structure. Modeled fields calculated from developed code are also well matched with the layered-earth ones for a model with dielectric anomaly as well as conductive anomaly. In a vertical electric dipole source case, however, the discontinuity of field variables causes the conventional nodal based FEM to include a lot of errors due to the vector parasite. Even for the case, the vector based FEM gave almost the same results as the layered-earth solution. The magnetic fields induced by a dielectric anomaly at high frequencies show unique behaviors different from those by a conductive anomaly. Since our 3-D EM modeling code can reflect the effect from a dielectric anomaly as well as a conductive anomaly, it may be a groundwork not only to apply high frequency EM method to the field survey but also to analyze the fold data obtained by high frequency EM method.

• Journal of the Korea Concrete Institute
• /
• v.25 no.5
• /
• pp.529-537
• /
• 2013

The aim of the current study is to develop a nonlinear isoparametric layered frame finite element (FE) analysis of FRP strengthened reinforced concrete (RC) beam or column members by a force-based FE formulation. In sections, concrete is modeled in the triaxial stress-strain relationship state and the FRP sheet is modeled as layered composite materials in two-dimension. The element stiffness matrix derived by the force-based FE has the force-interpolation functions without assuming the displacement shape functions. A lateral load test of RC column strengthened by GFRP sheets was analyzed by the developed force-based FE model. From comparative studies of the experimental and analysis results, it was shown to compare with the stiffness FE method that the force-based FE analysis could give more accurate predictions in the overall lateral load-deflection response as well as in nonlinear deformations and damages in the column plastic hinge region.

• Journal of Communications and Networks
• /
• v.3 no.4
• /
• pp.297-306
• /
• 2001

In the last couple of years service management has gained more and more momentum in the research community. Nowadays, as complexity of IT-services is increasing, these services are usually composed of interdependent, layered services hosted by various providers. Therefore, a strong cooperation of providers involved in service provisioning is needed, especially regarding their management processes and systems. One important step is to establish a common understanding about service-related terms in order to be able to specify service functionality and the resulting management tasks. Additionally, means to analyze and identify the necessary actors and the corresponding inter- and intra-organizational relationships are needed. This paper presents an extended version of the MNM service model which provides a generic model defining commonly needed service-related terms, concepts and structuring rules in a general and unambiguous way. Furthermore, we demonstrate the application of the MNM service model by modeling a riser help desk service based on a concrete scenario. The experience gained from modeling is used to discuss the benefits of service modeling in general.

• Journal of the Korean housing association
• /
• v.22 no.4
• /
• pp.121-132
• /
• 2011

Hanok with a long tradition in our country, but a significant period of modernization in the process of being cut off did not have continuity. Many of Hanok aging, according to the rapid residential development and life-changing was the subject of a complaint. Conversely, the benefits of Hanok was given to the advantages that compare to a monotonous mass housing of apartments. Despite these changes and the potential of these social needs and demands Hanok quickly did not respond: First, for the life of contemporary and traditional Hanok with a form of gap is a matter of space and style. Economy and lifestyle $20,000 for the era of Hanok was to develop a model for spatial configurations. Second, Hanok in a low density, is evaluated to aging, because increasing the economic utilization of land and tailored to their needs as a Hanok housing requires the development of a model, but this did not present a layered model. The purpose of this study is a modern residential Hanok persistence of this set to have 1) the spatial characteristics of traditional and modern urban life Hanok living space that meets the requirements of the degree of each other, to find sustainable elements, and 2) these demands the modern residential area type, combined with a set of Hanok 3) Korea Hanok cultural characteristics which set is created to residential housing types is to develop a basic research.

• Journal of the Korean Society for information Management
• /
• v.28 no.3
• /
• pp.123-139
• /
• 2011

Context-awareness as a key technology of ubiquitous computing needs a context model that understands and processes situational information coming from diverse sensors and devices, and can be applied diversely in various domains. Semantic web based ontologies use structured standard format and express meaning of information, so it is possible to recognize effectively context-awareness situations, allowing the system to share information and understand situation by inference. In this paper, we propose a layered ontology model to support generality and scaleability of the context-awareness system, and applied the model to u-Convention domain. In addition, we propose a effective reasoning method to handle compound situation by combining OWL-DL and SWRL rules.