• Journal of the Korean Geotechnical Society
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• v.28 no.8
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• pp.55-63
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• 2012

The evaluation of shear modulus (or shear wave velocity) profile of the site is very important in various fields of geotechnical engineering and various surface wave methods have applied to determine the shear wave velocity profiles and showed good performance. Surface wave methods evaluate the dispersion curve in the field and determine the shear wave velocity profile through the inversion process. In this paper, the automated inversion process using the genetic algorithm is developed for HWAW method which is one of surface wave methods recently developed. The proposed method uses the error function based on the wavelength domain dispersion curve and can determine the reliable shear wave velocity profile not only in shallow depth but also in deep depth. To estimate the validity of the proposed method, numerical simulations and field test were performed and the proposed method was applied to determine the shear wave velocity profiles. Through the numerical simulations and field applications, the promising potential of the proposed method was verified.

• Journal of the Korean Geographical Society
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• v.44 no.2
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• pp.187-205
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• 2009

Failures on network components of a public transportation system can give rise to the severe degradation of entire system functionality. This paper aims at exploring how potential failures can affect the system flows and reliability of subway network systems in Metropolitan Seoul. To evaluate the range of impacts of disruptions, this research employs a probabilistic approach, network reliability. Network reliability measures the network resiliency and probability of flow loss under a variety of simulated disruptions of critical network components, transfer stations in subway system. By identifying the best and worst scenarios associated with geographical impact, as well as evaluating the criticality of transfer stations, this research presents some insights for protecting current subways systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.3
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• pp.273-288
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• 1997

In this work, the electromagnetic waves scattered from 2-dimensional random rough surfaces are characterized by the $4\times4$ Mueller matrix elements. The full wave solutions are used to compute these elements. The results of the full wave solutions for 1-dimensional random rough surfaces were shown to agree well with those of the experiment and the method of moments. The Mueller matrix elements are related to the like and cross polarized radar cross sections as well as to the relative phase of the vertically and horizontally polarized waves. The $4\times4$ Mueller matrix elements completely characterize electromagnetic scattering from target. The computed results of this paper can be useful to the field of active remote sensing or RCS.

• The Korean Journal of Archival Studies
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• no.42
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• pp.327-361
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• 2014

'Special Records' means the records created by the government power authorities like security, investigation, intelligence agencies. Even after the enactment of the Public Records Act, these kinds of records were out of the control of the National Archives of Korea. The reason was certainly complex including the loss of control power caused by the National Archives' low status, limitation of the legislation and lack of positive measures for the transfer of classified records. But core records of the government power authorities should be transferred to the National Archives for the righteous records culture in the democracy. This paper investigates the problems concerned with the transfer of classified records of the special records center, looking for a practical alternative.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.79-87
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• 2009

International Standard Organization for Standardization Technical Committee 211(ISO TC 211) aims to define and develop standards for information concerning objects or phenomena that are directly or indirectly associated with a location relative to the Earth. ISO TC 211 is working with LADM as a new project based on the existing research which is CCDM. Land Administration Domain Model is, as a international standard model, mainly connected to administration law, spatial surveying components related to cadastre all over the world and provides an extensive basis for an efficient and effective land administration system to avoid reinvention and re-implemention. Further, LADM helps to communicate land information both within a country and between different countries. This study introduces what LADM is and researches how to adopt administration law, spatial surveying components of LADM for Korea Land Information System(KLIS).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.146-152
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• 2016

This paper describes a multi-physics analysis of a high resolution winding type resolver and rotary transformer using FEM (Finite Element Method). The rotary transformer boosts the input voltage to a high voltage which can be input into the rotor windings of the resolver. Through multi-physics models of the transformer and resolver, the characteristics of the output signals for the resolver system with high resolution can be derived. Moreover, the circuit model of the interface part between the transformer and resolver should be considered, because of the calculation of the input current to the resolver. The winding type resolver is composed of 32x and 1x stator windings for high resolution. Then, the output signals of the stator windings, which make sinusoidal SIN and COS waves with a $90^{\circ}$ phase difference, are verified.

• Archives of design research
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• v.16 no.3
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• pp.341-350
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• 2003

The topic of 21st century's culture is the appearance of digital media. It made changes as big as the industrial revolution, and our society is now ruled by the digital media. The main objective of this study is to forecast the direction of current visual design education by researching and analyzing how the introduction of digital media is influencing the evolution of visual design's identity, which is an ever changing and developing science. Also, since the rain target of digital media is the young generation, the change in the method of expressing visual language is inevitable In fact, there have been a lot of changes in the methods of creating and distributing visual communication due to the introduction of digital media. In the past, most educational institutions of design had similar objectives, curriculums and teaching methods to provide education that prepares students for practical business. However, in this digital media era, the application and utilization of visual design are uncomparably diversified, and it is generally classified as interaction. The purpose of this study is to find a wat to train visual design professionals in this digital era. For this purpose, this study will identify a new educational system that fulfills the demands of this society by fusing the traditional education and the new digital education, and will suggest what an design education institute that is ahead of the demands of society should be like.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.570-578
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• 2002

Cathodic protection is widely used to prevent corrosion of steel materials buried in the underground and sea. As a rectifier for cathodic protection, the conventional phase-controlled rectifiers have been used so far in spite of such shortcomings as large volume, heavy weight and floor power factor. In order to overcome such disadvantages, this paper proposes a new module-type switching rectifier for cathodic protection, which is composed of two parts, namely, AC/DC converter and module- type DC/DC converter. The AC/DC converter is a single-phase IGBT PWM rectifier, thus resulting in almost unity power factor and controlled DC output voltage. The module-type DC/DC converter operates under ZVS/ZCS switching condition to permit high frequency switching operation. It enables to use high-frequency transformer for electrical isolation, thus reducing volume and weight of overall system and improving system efficiency. It should be anticipated that the proposed rectifier techniques apply to the similar technical areas.

• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.129-140
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• 2004

KAO(Korea Astronomy Observatory) GPS group has developed an iRTK system as a near-real time positioning system using GPS carrier phase data. We focused on improving the accuracy of positioning through the updated capability of data processing of KAO's iRTK system using low-cost L1 carrier phase receiver. The accuracy of a positioning was demonstrated by Extended Kalman filter. Experiments were accomplished using from 30m to 20km baselines. Within 10km, the positioning accuracy was improved by approximately 50-70% to the previous study using one minute observable data. However, it took two minutes to obtain 1m level positioning accuracy at 20km point. We expect that the developed iRTK system can be applied to the various fields of GPS in near-real time positioning.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.21-33
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• 2020

This study develops a simulator for determining the sonar sensor configuration of unmanned underwater vehicles (UUVs) based on a scenario, in order for UUVs to conduct an effective anti-submarine warfare (ASW). First, we analyze the missions and operational concepts of UUVs in the field of ASW, and then select a Hold-at-Risk scenario as the one with the highest priority. Next, for modeling the components of a simulator, the motion, acoustic characteristic, and environment condition of the platforms (UUV and target submarine) are specified. Especially, based on the beam pattern of each sonar configuration considered in this paper, the passive sonar equation is used to verify target detection, and we further estimate the azimuth and elevation of the target using amplitude and phase of the received signal, respectively. The simulation results show the performance tendency depending on the sonar sensor configurations of a UUV, and the simulator provides a high applicability under various scenarios.