• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.66-75
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• 1999

Many researchers have developed the measurement technique of in-cylinder flow. Recently, there are lots of studies on steady flow with different SCV geometries. In this study the flow characteristics of four-valve cylinder head were examined in a steady test rig for different SCV open ratios. Each swirl ratio of several SCV angle was quantified by swirl impulse meter and 2D-LDV measurement. The results showed that the swirl ratio was controlled between 2.3 and 3.8 based on SCV angles. The velocity distributions of in-cylinder flow field were measured by 2-D LDV test and visualized swirl and tumble flow pattern at different positions. In this engine , we found out that the swirl was dominant flow.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.423-430
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• 2012

This study was conducted to qualify the equality of the flow distribution from open channel between rapid mixing basin and flocculation basins in a domestic S_ water treatment plant, and to suggest a remedy for improving the equality. In order to evaluate the feasibility of the suggested remedy, computational fluid dynamics (CFD) technique are used, and for verifying the CFD simulation results tracer tests were carried out. From the results of CFD simulation and tracer tests, it was investigated that the modification of hydraulic structure in the distribution channel, which is to install the longitudinal orifice baffle in flow direction, could improve the equality of the flow distribution over 75%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.347-354
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• 2009

In this paper, we propose a new transmit diversity technique for multiple-input multiple-output (MIMO) systems to improve the link level performance of open-loop systems. By cyclically applying a predetermined set of preceding weight vectors, artificially induced fluctuation is created to achieve additional diversity gain in flat fading channels. To design the set of the precoding vectors, we exploit the knowledge on the distribution of near optimum Preceding vectors observed in a beamforming scheme based on the rotation transformations. Simulation results demonstrate that the proposed open-loop diversity scheme with an arbitrary number of transmit antennas achieves a full diversity gain with computational complexity comparable to a single-input single-output (SISO) system.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.895-898
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• 2017

동영상 플랫폼 확산에 따라 영상 콘텐츠 수요와 공급이 폭발적으로 성장하여 영상 콘텐츠 확산에 큰 영향을 미치고 있다. 이와 같은 콘텐츠 확산으로 인해 전문가의 영역에 해당하는 영상 제작 기술이 일반적인 기술의 범주로 인식될 만큼 영상 처리 및 제작에 대한 기술의 발전이 나날이 급증하고 있으며 이러한 기술의 발전에 따라 사람의 수작업을 통해서만 영상을 조절하던 과정 또한 객체 추적 기술을 활용함에 따라 자동화 과정이 가능하게 되었다. 본 연구에서는 객체 추적 알고리즘 중 특징 점을 키포인트로 나눠 객체를 추적하는 OpenCV 기반 CMT 알고리즘으로 라즈베리파이를 활용하여 객체를 추적하는 기법을 소개한다. 본 시스템은 방송용 카메라의 객체 추적에 잘 활용될 수 있다.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.1041-1046
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• 2002

A railway open deck plate girder bridge without ballast should support relatively heavier vehicle loads compared with its self-weight. For such a reason, actual dynamic response of the bridge is considerably differing with normal prediction because additional masses added from vehicle to a bridge have an effect on the dynamic characteristics of the bridge. These differences affect to the estimation of a natural frequency change that adopted for one of the evaluation technique of strength decrease, and these make trouble to the analysis of a natural frequency from the field test data that measured at the bridge subjected to a running vehicle. In this study, classification of mass participation ratio for each component of open deck plate girder bridge without ballast and the comparison according to the change of vibration characteristics for the case of subjected to a running vehicle were accomplished.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.57-68
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• 2017

The Linked Open Data(LOD) cloud is quickly becoming one of the largest collections of interlinked datasets and the de facto standard for publishing, sharing and connecting pieces of data on the Web. Data publishers from diverse domains publish their data using Resource Description Framework(RDF) data model and provide SPARQL endpoints to enable querying their data, which enables creating a global, distributed and interconnected dataspace on the LOD cloud. Although it is possible to extract structured data as query results by using SPARQL, users have very poor in analysis and visualization of RDF data from SPARQL query results. Therefore, to tackle this issue, based on Formal Concept Analysis, we propose a novel approach for analyzing and visualizing useful information from the LOD cloud. The RDF data analysis and visualization technique proposed in this paper can be utilized in the field of semantic web data mining by extracting and analyzing the information and knowledge inherent in LOD and supporting classification and visualization.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.281-290
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• 2012

Hydrodynamic analysis of a surface-piercing body with an open chamber was performed with incident regular waves and forced-heaving body motions. The floating body was simulated in the time domain using a 2D fully nonlinear numerical wave tank (NWT) technique based on potential theory. This paper focuses on the hydrodynamic behavior of the free surfaces inside the chamber for various input conditions, including a two-input system: both incident wave profiles and forced body velocities were implemented in order to calculate the maximum surface elevations for the respective inputs and evaluate their interactions. An appropriate equivalent linear or quadratic viscous damping coefficient, which was selected from experimental data, was employed on the free surface boundary inside the chamber to account for the viscous energy loss on the system. Then a comprehensive parametric study was performed to investigate the nonlinear behavior of the wave-body interaction.

• Journal of Information Processing Systems
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• v.19 no.1
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• pp.33-45
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• 2023

This paper proposes an algorithm that automatically converts images into Pipo, painting images using OpenCV-based image processing technology. The existing "purity," "palm," "puzzling," and "painting," or Pipo, painting image production method relies on manual work, so customized production has the disadvantage of coming with a high price and a long production period. To resolve this problem, using the OpenCV library, we developed a technique that automatically converts an image into a Pipo painting image by designing a module that changes an image, like a picture; draws a line based on a sector boundary; and writes sector numbers inside the line. Through this, it is expected that the production cost of customized Pipo painting images will be lowered and that the production period will be shortened.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.203-210
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• 2023

In this paper, we develope a stock trading system that automatically buy and sell stocks in Kiwoom Securities' HTS system. The system is made by using Kiwoom Open API+ with the Python programming language. A trading strategy is based on an enhanced system query method called a Condition-Search. The Condition-Search script is edited in Kiwoom Hero 4 HTS and the script is stored in the Kiwoom server. The Condition-Search script has the advantage of being easy to change the trading strategy because it can be modified and changed as needed. In the HTS system, up to ten Condition-Search scripts are supported, so it is possible to apply various trading methods. But there are some restrictions on transactions and Condition-Search in Kiwoom Open API+. To avoid one problem that has transaction number and frequency are restricted, a method of adjusting the time interval between transactions is applied and the other problem that do not support a threading technique is solved by an IPC(Inter-Process Communication) with multiple login IDs.

• Journal of KIBIM
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• v.13 no.3
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• pp.39-47
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• 2023

This study aims to introduce a model for enhancing community well-being through the utilization of public open data. To objectively assess abstract notions of residential satisfaction, text data from complaints is analyzed. By leveraging accessible public data, costs related to data collection are minimized. Initially, relevant text data containing civic complaints is collected and refined by removing extraneous information. This processed data is then combined with meaningful datasets and subjected to topic modeling, a text mining technique. The insights derived are visualized using Geographic Information System (GIS) and Application Programming Interface (API) data. The efficacy of this analytical model was demonstrated in the Godeok/Gangil area. The proposed methodology allows for comprehensive analysis across time, space, and categories. This flexible approach involves incorporating specific public open data as needed, all within the overarching framework.