• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.83-92
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• 2017

This paper deals with numerical analysis of behavior of curved mechanically stabilized earth(MSE) walls with geosynthetics reinforcement. Unlike typical concrete retaining walls, MSE wall enables securing stability of higher walls without being constrained by backfill height and is currently and widely used to create spaces for industrial and residential complexes. The design of MSE walls is carried out by checking external stability, similarly to the external checks of conventional retaining wall. In addition, internal stability check is mandatory. Typical stability check based on numerical analysis is done assuming 2-dimensional condition (plane strain condition). However, according to the former studies of 3-dimensional MSE wall, the most weakest part of a curved geosynthetic MSE wall is reported as the convex location, which is also identified from the studies of the laboratory model tests and field monitoring. In order to understand the behaviour of the convex location of the MSE wall, 2-dimensional analysis clearly reveals its limitation. Furthermore, laboratory model tests and field monitoring also have restriction in recognizing their behaviour and failure mechanism. In this study, 3-dimensional numerical analysis was performed to figure out the behaviour of the curved part of the geosynthetic reinforced wall, and the results of the straight-line and curved part in the numerical analysis were compared and analysed. In addition, the behaviour characteristics at each condition were compared by considering the overburden load and relative density of backfill.

• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.554-569
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• 2005

In the semistructured distributed documents, it is very difficult to formalize and implement the query processing system due to the lack of structure and rule of the data. In order to precisely retrieve and process the heterogeneous semistructured documents, it is required to handle multiple mappings such as 1:1, 1:W and W:1 on an element simultaneously and to generate the schema from the distributed documents. In this paper, we have proposed an query processing algorithm for querying and answering on the heterogeneous semistructured data or documents over distributed systems and implemented with a metadata interface. The algorithm for generating local queries from the global query consists of mapping between g1oba1 and local nodes, data transformation according to the mapping types, path substitution, and resolving the heterogeneity among nodes on a global input query with metadata information. The mapping, transformation, and path substitution algorithms between the global schema and the local schemas have been implemented the metadata interface called DBXMI (for Distributed Documents XML Metadata Interface). The nodes with the same node name and different mapping or meanings is resolved by automatically extracting node identification information from the local schema automatically. The system uses Quilt as its XML query language. An experiment testing is reported over 3 different OEM model semistructured restaurant documents. The prototype system is developed under Windows system with Java and JavaCC compiler.

• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.197-201
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• 2014

As the importance of rare metal is increasing globally, Japan introduced the concept of Strategic Elements in 2004, and started Strategic Elements Project in 2007. The Goal of this project run by MEXT (Ministry of Education, Culture, Sports, Science and Technology) is to develop high-function materials and components that do not use rare or harmful elements by studying the role and characteristics of the elements that compose materials and components and decide their functions and characteristics. In September 2010, Japanese coast guard arrested a Chinese fishing boat near Senkaku Islands (Diaoyudao Islands by China), which escalated to the territory issue and eventually a big diplomatic and economic conflict. In order to put pressure on Japanese Government, China used an economic option, which is the ban of rare earth export to Japan. This incident doubled Japan's motivation to develop Strategic Elements and put more efforts into this Project. MEXT set the following three research areas in February 2012: Study of alternative materials using sufficient and harmless elements, Study of applications for the high-functions of Strategic Elements, Study of practical design for components using Strategic Elements. Through a course of gathering the opinion of professionals, MEXT settled down with the following 4 research and study areas for the Strategic Elements Project in June 2012. 1. Magnetic materials to replace Dy, Nd. 2. Catalyst/Battery materials to replace Pt, Rh/Li, Co. 3. Electronic materials to replace In, Ta. 4. Structural materials to replace Nb, Mo. This paper deals with the first area and reviews the results of the research and study as of now.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.174-181
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• 2011

An airborne sensor is developed for remote sensing on an aerial vehicle (UV). The sensor is an optical payload for an eletro-optical/infrared (EO/IR) dual band camera that combines visible and IR imaging capabilities in a compact and lightweight package. It adopts a Ritchey-Chr$\'{e}$tien telescope for the common front end optics with several relay optics that divide and deliver EO and IR bands to a charge-coupled-device (CCD) and an IR detector, respectively. The EO/IR camera for dual bands is mounted on a two-axis gimbal that provides stabilized imaging and precision pointing in both the along and cross-track directions. We first investigate the mechanical deformations, displacements and stress of the EO/IR camera through finite element analysis (FEA) for five cases: three gravitational effects and two thermal conditions. For investigating gravitational effects, one gravitational acceleration (1 g) is given along each of the +x, +y and +z directions. The two thermal conditions are the overall temperature change to $30^{\circ}C$ from $20^{\circ}C$ and the temperature gradient across the primary mirror pupil from $-5^{\circ}C$ to $+5^{\circ}C$. Optical performance, represented by the modulation transfer function (MTF), is then predicted by integrating the FEA results into optics design/analysis software. This analysis shows the IR channel can sustain imaging performance as good as designed, i.e., MTF 38% at 13 line-pairs-per-mm (lpm), with refocus capability. Similarly, the EO channel can keep the designed performance (MTF 73% at 27.3 lpm) except in the case of the overall temperature change, in which the EO channel experiences slight performance degradation (MTF 16% drop) for $20^{\circ}C$ overall temperate change.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.46-52
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• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Journal of Service Research and Studies
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• v.9 no.2
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• pp.31-40
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• 2019

In this paper, we have studied the improvement of operational control for the enhancement of business continuity of information system becoming more important with the development of information technology such as big data, Iot, and artificial intelligence. The operational management and audit guidance of the current information system, which is coming in the fourth industrial age, where various services, data and industries are converged, is based on the existing general information system pattern and needs to be improved. The provision of services at fixed times is linked to the survival of enterprises and countries and serves as a key element. Therefore, it is necessary to study the application of optimized check items of the operation audits to minimize the service interruption damage of the information system and to provide the stable service in terms of business continuity management. To accomplish this, the check items presented in the operational control of the information system were derived by combining the PDCA step contents and 8 resource requirements provided in ISO 22301. From the point of view of increasing the business continuity according to the derivation criteria of the inspection items, the operational inspection check items were derived by exemplifying the improved check items and review items of the information system operation audit and the products to be checked during the operational audit. The check items were divided into management audit improvement check items for service continuity management, and operational audit improvement check items for performance and availability management. The average score of the IT professionals' survey on the suitability of the proposed checklist was 4.63, which was concluded to be appropriate.

• Land and Housing Review
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• v.4 no.1
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• pp.33-42
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• 2013

This study which are recognized that the lack of empirical research about the efficiency of the elements of environmentally friendly housing development planned presented housing design elements and policies to revitalize for the reduction of greenhouse gas emissions by analyzing the effectiveness of reduction of greenhouse gas output. In addition, it used various models of DEA which are accepted until now effective technique to evaluate the performance of the organization. In conclusion, there are effective 5 regionals which are Seoul, Incheon, Ulsan, South Chungcheong Province, South Gyeongsang Province. other regionals was analyzed to be inefficient. The conclusion from this study are as follows: First, in case of 11 regionals which are analyzed to be inefficient, they have to difference plan elements to make up. So each region should establish strategy to complement vulnerability. Second, not only internal architectural factors but institutional, and external environmental factors also affect the reduction of greenhouse gas emissions. And weighted scores also were moderately high. But levels of weighted scores still less than the ratio of Good quality housing. So it can be determined that evaluation of individual architecture still considered important. It need to pay more attention to the operating system and the external environmental factors.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.1
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• pp.35-43
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• 2009

Two types of piloti-type high-rise RC building structures having irregularity in the lower two stories were selected as prototypes, and nonlinear time history analysis was performed using OpenSees to verify the analysis technique and to investigate the seismic capacity of those buildings. One of the buildings studied had a symmetrical moment-resisting frame (BF), while the other had an infilled shear wall in only one of the exterior frames (ESW). A fiber model, consisting of concrete and reinforcing bar represented from the stress-strain relationship, was adapted and used to simulate the nonlinearity of members, and MVLEM (Multi Vertical Linear Element Model) was used to simulate the behavior of the wall. The analytical results simulate the behavior of piloti-type high-rise RC building structures well, including the stiffness and yield force of piloti stories, the rocking behavior of the upper structure and the variation of the axial stiffness of the column due to variation in loading condition. However, MVLEM has a limitation in simulating the abrupt increasing lateral stiffness of a wall, due to the torsional mode behavior of the building. The design force obtained from a nonlinear time history analysis was shown to be about $20{\sim}30%$ smaller than that obtained in the experiment. For this reason, further research is required to match the analytical results with real structures, in order to use nonlinear time history analysis in designing a piloti-type high-rise RC building.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.34-45
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• 2004

Existing Semangeum's water balance analysis simplifies whole basin to single basin and achieved volume of effluence that produce by Kajiyama way to foundation. But Semangeum is complicated and various rice-wine strainer supply system. And there is difficulty to apply as elastic when water balance element is changed at free point. Divided to unit possession station for suitable water balance analysis model application to Semangeum in this study. And developed basin water balance model of GIS base that can do details analysis is bite about development and transfer of an appropriation in the budget of basin water resources. Achieved study including abstraction and concept design that use UML (unified modeling language) diagram for details analysis, stream network composition for rice-wine strainer supply system application, preprocessing of GIS base and postprocessing module development, model revision and verification etc. Support of this water balance analysis model is available to establish efficient water resources administration plan through outward flow process analysis of water resources. And support is considered to be possible in more convenient and, reasonable water resources administration way establishment by minimizing manual processing in systematic water resources government official to user and support diversified analysis system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1380-1393
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• 2010

This paper presents a design, fabrication and the test results of planar active electronically scanned array(AESA) radar prototype for airborne fighter applications using transmit/receive(T/R) module hybrid technology. LIG Nex1 developed a AESA radar prototype to obtain key technologies for airborne fighter's radar. The AESA radar prototype consists of a radiating array, T/R modules, a RF manifold, distributed power supplies, beam controllers, compact receivers with ADC(Analog-to-Digital Converter), a liquid-cooling unit, and an appropriate structure. The AESA antenna has a 590 mm-diameter, active-element area capable of containing 536 T/R modules. Each module is located to provide a triangle grid with $14.7\;mm{\times}19.5\;mm$ spacing among T/R modules. The array dissipates 1,554 watts, with a DC input of 2,310 watts when operated at the maximum transmit duty factor. The AESA radar prototype was tested on near-field chamber and the results become equal in expected beam pattern, providing the accurate and flexible control of antenna beam steering and beam shaping.