• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.267-273
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• 2024

Using a cloud-based vertex AI platform that can develop an artificial intelligence learning model without coding, this study easily developed an artificial intelligence learning model by the non-professional general public and confirmed its clinical applicability. Nine dental diseases and 2,999 root disease X-ray images released on the Kaggle site were used for the learning data, and learning, verification, and test data images were randomly classified. Image classification and multi-label learning were performed through hyper-parameter tuning work using a learning pipeline in vertex AI's basic learning model workflow. As a result of performing AutoML(Automated Machine Learning), AUC(Area Under Curve) was found to be 0.967, precision was 95.6%, and reproduction rate was 95.2%. It was confirmed that the learned artificial intelligence model was sufficient for clinical diagnosis.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.28 no.1
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• pp.25-44
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• 2017

This study was to suggest display of RDA resource type in OPAC efficiently. Literature reviews and users test and preference survey were used as research methods. The 4 ways for the display of RDA resource type were suggested. First, GMD and the resource type code(bcode2) invented by library itself as well as leader/06, 007, and 008 field should be used for converting AACR2 resource type to RDA resource type in the bibliographic records. Second, RDA resource type vocabularies applicable to Korean cataloging environment should be designed and described in 33X subfield ${\blacktriangledown}9$ and detailed resource terms described in 34X should be also expressed in OPAC. Third, two option is suggested as content type and carrier type display separately and as content type and carrier type combination. Fourth, 336, 338 filed, leader/07 bibliographic level, 008/30-31 Literary text for sound recordings, 34X field were useful to develop user centered resource type icon. This study would be able to increase the utilization of RDA resource types and help the users to understand the RDA resource type in OPAC.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.310-313
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• 2005

5GHz를 사용하고 최소6Mbps에서 최대 54Mbps까지 지원하는 IEEE 802.11a 무선 랜 에서는 데이터의 전송중에 발생하는 랜덤오류 및 연집오류의 정정을 위해서 길쌈부호기와 인터리버를 규정하고 있다. 길쌈부호기에서 다양하고 높은 데이터 전송율을 확보하기 위해서 변조방식과 전송율에 따라 높은 부호율을 얻기 위해 여러 개의 펑쳐링 기법을 사용해서 2/3와 3/4과 같은 높은 부호율이 얻어지도록 하고 있다. 펑쳐링을 거친 데이터는 Coding rate만큼의 비율로 데이터가 많아지고 이 데이터를 처리하기 위해서 가변클럭을 사용해야 한다. 가변클럭의 사용은 동기화 및 back-end 작업 시 여러 가지 문제를 발생시킨다. 본 논문에서 펑쳐링의 출력 비트를 바꾸고 인터리버에서 사용되는 메모리를 8x1의 메모리로 세분화 함으로써 Code rate에 상관없이 하나의 클럭으로 데이터의 병목현상을 처리 할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.5
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• pp.15-20
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• 2012

In this paper, we show new method to find the error locations of received Reed-Solomon code word. New design is much faster and has much simpler logic circuit than the former design method. This optimization was possible by very simplified square/$X^4$ calculating circuit, parallel processing and not using the very complex Divider. The Reed Solomon decoder using this new Chien Machine can be applicated for data protection of almost all digital communication and consumer electronic devices.

• International Journal of Concrete Structures and Materials
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• v.6 no.2
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• pp.79-85
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• 2012

This paper presents the differences in growth of time-dependent strain values in reinforced cement concrete (RCC) and pre-stressed concrete (PSC) flexural members through experiment. It was observed that at any particular age, the time-dependent strain values were less in RCC beams than in PSC beams of identical size and grade of concrete. Variables considered in the study were percentage area of reinforcement, span of members for RCC beams and eccentricity of applied pre-stress force for PSC beams. In RCC beams the time-dependent strain values increases with reduction in percentage area of reinforcement and in PSC beams eccentricity directly influences the growth of time-dependent strain. With increase in age, a non-uniform strain develops across the depth of beams which influence the growth of concave curvature in RCC beams and convex curvature in PSC beams. The experimentally obtained strain values were compared with predicted strain values of similar size and grade of plane concrete (PC) beam using ACI 318 Model Code and found more than RCC beams but less than PSC beams.

• Computers and Concrete
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• v.20 no.2
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• pp.129-143
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• 2017

Seismic design of reinforced concrete (RC) structures requires a certain minimum level of flexural ductility. For example, Eurocode EN1998-1 directly specifies a minimum flexural ductility for RC beams, while Chinese code GB50011 limits the equivalent rectangular stress block depth ratio at peak resisting moment to achieve a certain nominal minimum flexural ductility indirectly. Although confinement is effective in improving the ductility of RC beams, most design codes do not provide any guidelines due to the lack of a suitable theory. In this study, the confinement for desirable flexural ductility performance of both normal- and high-strength concrete beams is evaluated based on a rigorous full-range moment-curvature analysis. An effective strategy is proposed for flexural ductility design of RC beams taking into account confinement. The key parameters considered include the maximum difference of tension and compression reinforcement ratios, and maximum neutral axis depth ratio at peak resisting moment. Empirical formulae and tables are then developed to provide guidelines accordingly.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.148-151
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• 2007

The Korea Meteorological Administration has been operating a tsunami warning system which is based on tsunami scenario database for the East Sea. Recently, the tsunami scenario database for the Yellow sea and the East China sea is also generated so that the tsunami warning system is extended to the whole Korean seas. Tsunami scenario database includes tsunami arrival times and heights generated by performing huge numbers of tsunami propagation simulations. A leap-frog method for shallow water equation is used for the simulation. The simulation code is parallellized via Message Passing Interface and has run on Cray X1E.

• Annual Conference on Human and Language Technology
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• 1995.10a
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• pp.67-72
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• 1995

국제 표준화 기구 (ISO) 에서 1992 년 ISO 10646-1 을 확정하였다. ISO 10646-1에 들어 있는 국제 표준 한글 부호계에는 현재까지 발견된 옛한글 글자가 모두 들어 있다. 이전에는 옛한글에 대한 표준 부호계가 없어서 옛한글 자료에 대한 전산화에 큰 걸림돌이 되었으나, 국제 표준 한글 부호계의 등장으로 이러한 문제가 해결되었다고 할 수 있다. 본 논문에서는 국제 표준 한글 부호계를 유닉스의 X-window 환경에서 지원하는 방안에 대해 살펴보고, 국제 표준 한글 부효계를 지원하는 관계형 데이터베이스 한글 사용자 질의 환경을 개발하므로써, 지원 방안의 실증과 함께 옛한글 자료를 데이터베이스화하기 위한 바탕을 마련하였다.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.44.1-44.1
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• 2015

We set up a project to make spectrometers for single dish observations of the Korean VLBI Network (KVN), a new future multi-beam receiver of the ASTE (Atacama Submillimeter Telescope Experiment), and the total power (TP) antennas of the Atacama Large Millimeter/submillimeter Array (ALMA). Traditionally, spectrometers based on ASIC (Application-Specific Integrated circuit) and FPGA (Field-Programmable Gate Array) have been used in radio astronomy. It is, however, that a Graphics Processing Unit (GPU) technology is now viable for spectrometers due to the rapid improvement of its performance. A high-resolution spectrometer should have the following functions: poly-phase filter, data-bit conversion, fast Fourier transform, and complex multiplication. We wrote a program based on CUDA (Compute Unified Device Architecture) for a GPU spectrometer. We measured its performance using two GPU cards, Titan X and K40m, from NVIDIA. A non-optimized GPU code can process a data stream of around 2 GHz bandwidth, which is enough for the KVN spectrometer and promising for the ASTE and ALMA TP spectrometers.

• Advanced Composite Materials
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• v.18 no.1
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• pp.21-42
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• 2009

The vibration characteristics of post-buckled laminated composite doubly curved shells are investigated. The finite element method is used for the analysis of post-buckling and free vibration of post-buckled laminated shells. The geometric non-linear finite element model includes the general non-linear terms in the strain-displacement relationships. The shell geometry used in the present formulation is derived using an orthogonal curvilinear coordinate system. Based on the principle of virtual work the non-linear finite element equations are derived. Arc-length method is implemented to capture the load-displacement equilibrium curve. The vibration characteristics of post-buckled shell are performed using tangent stiffness obtained from the converged deflection. The code is first validated and then employed to generate numerical results. Parametric studies are performed to analyze the snapping and vibration characteristics. The relationship between loads and fundamental frequencies and between loads and the corresponding displacements are determined for various parameters such as thickness ratio and shallowness.