• Annual Conference of KIPS
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• 2007.11a
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• pp.463-466
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• 2007

웹기반 기업형 어플리케이션은 객체지향 언어로 개발되고, 데이터의 관리는 RDB(Relational Database)를 이용하여 구축된다. 두 시스템은 이질적 패러다임에 기인하여 모델의 불일치성(object-relational impedance mismatch)을 발생시킨다. 이 문제를 해결하고자 사용되는 객체-관계 매핑 프레임워크(ORM-Framework)는 RDB 의 테이블과 객체지향 언어의 객체를 매핑하는 구조로 복잡한 메타정보를 이용하여 동적으로 매핑하기 때문에 개발이 복잡하고, 변경에 유연하지 못하여 유지보수에 많은 어려움이 있다. 본 논문에서는 기존 ORM 프레임웍크의 복잡성을 해소하고, 변경에 유연한 퍼시스턴스 프레임워크를 제안한다. 제안되는 프레임워크는 SQL 을 래핑하는 구조로 테이블과 객체의 메타정보가 불필요하고, 정형화된 구조를 가진 래퍼의 사용으로 소스코드를 자동 생성하여 개발 및 유지보수의 편의성을 제공하고, 변경에 유연하다. 제안 프레임워크는 Hibernate, iBATIS 와의 테스트 결과 구동 매커니즘이 거의 동일한 iBATIS 와는 처리속도가 비슷했고, Hibernate 의 약 3 배 빠른 속도를 보였다. 코딩량은 Hibernate 대비 1/9, iBATIS 대비 1/4 을 나타냈다.

• Journal of Internet Computing and Services
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• v.18 no.6
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• pp.85-92
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• 2017

Recently, in the field of video surveillance, a Deep Learning based learning method has been applied to a method of detecting a moving person in a video and analyzing the behavior of a detected person. The human activity recognition, which is one of the fields this intelligent image analysis technology, detects the object and goes through the process of detecting the body keypoint to recognize the behavior of the detected object. In this paper, we propose a method for Body Keypoint Localization based on Object Detection using RGB-D information. First, the moving object is segmented and detected from the background using color information and depth information generated by the two cameras. The input image generated by rescaling the detected object region using RGB-D information is applied to Convolutional Pose Machines for one person's pose estimation. CPM are used to generate Belief Maps for 14 body parts per person and to detect body keypoints based on Belief Maps. This method provides an accurate region for objects to detect keypoints an can be extended from single Body Keypoint Localization to multiple Body Keypoint Localization through the integration of individual Body Keypoint Localization. In the future, it is possible to generate a model for human pose estimation using the detected keypoints and contribute to the field of human activity recognition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.161-172
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• 2021

Along with the emergence of technologies related to the 4th industrial revolution, all industry sectors are making efforts to dramatically increase productivity by actively introducing high-tech technologies. Recently, the MLIT (Ministry of Land, Infrastructure and Transport) is trying to solve problems related to low productivity and high accident rate in the construction industry by applying the 4th industrial revolution technologies to infrastructure construction through smart construction R&D projects. This research was performed as part of the smart construction R&D project supported by MLIT, and the purpose is to develop a module that automatically generates moving paths for construction equipment based on the earthwork plan for road construction. The generated moving path can be used to provide safe and efficient paths for construction equipment and to support MC and MG to work efficiently. The moving paths for construction equipment are created based on the Visibility Graph and a case study is performed to show how the paths are generated based on a given construction site.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.343-351
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• 2012

With the cooperation of many research institutes and railway companies, the next generation high speed train is under development for many years. To confirm the safety requirement of the developed high speed train, multibody dynamic analysis is implemented. Through this analysis, railway derailment and lateral guiding force simulation was evaluated according to UIC code 518 OR for international railway vehicle. Test results were compared by limit value of safety criteria. Safety evaluation results, according to international standards, would provide basic reference data of ensuring safety speed and track radius curve. The safety of the train at the maximum speed is verified by numerical analysis results.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.1-9
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• 2011

Researches on hypersonic aircraft technologies have been carried out to increase flight speeds. However, increase in flight speeds causes heat loads that could lead structural change of aircraft's component. Researches on cooling technologies using endothermic fuels are progressing in the USA, France and Russia to treat the heat loads. Endothermic fuels are liquid hydrocarbon aircraft fuels which are able to absorb the heat loads by undergoing endothermic reactions, such as thermal and catalytic cracking. In this study, methylcyclohexane, n-octane, and n-dodecane were selected as model endothermic fuels and experiments in endothermic properties were implemented. Experimental conditions were supercritical condition of each model fuels in which actual endothermic fuels were exposed. The object of this study is to identify endothermic properties of the model endothermic fuels and to predict endothermic properties of actual fuels such as kerosene fuels.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.367-374
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• 2003

A mediator-wrapper system, which is one of integration methods of heterogeneous databases, preserves a virtual integrated view rather than physical movement of the contents of each database. In order for a mediator to preserve a virtual integrated view, it requires the schema manager of the wrapper which communicates with local databases. This paper presents a schema manager of a wrapper that provides a mediator with XML schema which is generated from relational database schema. The XML schema manager supports a user-defined XML view. We present the view tree model which is used for materializing the use-defined XML view to generate XML schema, and the conversion algorithm based on the proposed view tree model. This model is can be uniformly applied to all schema managers of heterogeneous information sources.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.449-457
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• 2013

In this study, we performed a numerical analysis to investigate the effect of rotation on the blood flow and arterial wall behavior by using the FSI (fluid-structure interaction) technique. The geometry of the artery included 50% stenosis at the center. To simulate the rotational effect, 2-6 rps of axial velocity was applied to the arterial model. A spiral wave and asymmetric flow occurred due to the stenosis and axial rotation both in the rigid body model and in the FSI model. However, the arterial wall motion caused periodic and transient blood flow changes in the FSI model. The FRZ (fluid recirculation zone) decreased in the FSI model, which is a known predictor for the formation and vulnerability of plaque. Therefore, it is observed that arterial wall motion also influences the generation of the FRZ.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.54-54
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• 2011

기존의 착저식 방파제를 보완하기 위하여 부유식 방파제가 개발되었고, 많은 연구가 선행되어 왔다. 부유식 방파제의 최대 장점은 경제성과 친환경성이다. 그러나 부유식 방파제는 소파성능이 떨어진다는 단점이 있으며, 이를 개선하기 위해 잠재와 혼용, 배열형에 관한 연구등이 선행되어왔다. 그러나 이것은 경제성이라는 강점을 고려하지 못하였다. 그래서 본 연구에서는 부유식 방파제의 중요한 장점중 하나인 경제성을 고려해, 단면현상 변화만을 이용하여 부유식 방파제의 소파성능 개선하고자 하였다. RANS(Reynolds averaged Navier-Stokes) 방정식에 기초하여 VOF법과 $k-{\varepsilon}$ 난류모델을 결합한 수치모델인 CADMAS-SURF를 이용하였으며, 구조물 단면형상 변화를 이용해 와의 상호 간섭을 유도하였고, 이에 따른 투과율 변화를 관찰 하였다. 결과를 살펴보면 요철1 단면에서는 구조물 전면 하단부분과 구조물 후면 하단부분에서 와의 간섭이 일어났으며 가장 아래 요철 부분에서 유속의 전달현상이 보인다. 투과계수는 일반적인 부유식 방파제와 마찬가지로 L/B가 1~4사이 값인, 비교적 단주기에서는 0.3~0.4의 투과율을 보였으나 L/B가 5를 넘어가면서 0.45~0.55의 투과율을 보였고, 요철2 단면에서는 전면과 후면에서 발달한 와가 전, 후면 돌출부에 의해 바닥까지 전파되지 못하는 양상을 보였으며, 돌출부 사이 중앙부분에서 가장 활발한 와의 간섭을 관찰 할 수 있었다. 돌출부 아래에서 역시 강력한 와의 간섭을 보이고 있다. 투과율 역시 가장 낮은 값을 보였으며 비교적 단주기 구간인 B/L 1~4 에서는 0.2~0.35 사이의 값을 가졌으며 5~10사이구간에서는 0.35~0.34의 값을 보이고 있다. 이 같은 결과는 와의 간섭이 가장 활발하게 나타난 결과로 보인다. 그리고 요철 3단면에서는 전면 돌출부 끝단에서의 활발한 와의 간섭을 관찰 할 수 있었다. 투과율은 세 단면 중 가장 높은 값의 투과율을 보이지만 B/L 3~4 구간에서 요철1 경우보다 낮은 값의 투과율을 보이고 있다. 결과에서 보듯이 도출부의 적절한 조합과 배치를 통해 언급한 연구목표(와의 생성과 간섭, 방파효율 개선)를 달성하였고 추후에 돌출부의 크기와 배치, 흘수의 영향, 수심의 영향 등을 고려한 연구가 진행된다면 더욱 우수한 단면형상을 개발 할 것이라 예상된다.

• Membrane Journal
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• v.13 no.4
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• pp.257-267
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• 2003

For the treatment of reactive phenolic resin waste, a simulation model of pervaporative dehydration process has been developed through hollow fiber membrane module. Some of basic parameters were determined directly from dehydration of the waste liquid through a flat sheet membrane to get realistic values. The simulation model was verified by comparing the simulated values with experimental data obtained from hollow fiber membrane module. Hollow fiber membranes with active layer coated on inside fiber were used, and feed flew through inside hollow fiber. Feed flow rate affected membrane performances and reaction by providing a corresponding temperature distribution of feed along with fiber length. Feed temperature is also a crucial factor to determine dehydration and reaction behavior by two competing ways; increasing temperature increases permeation rate as well as water formation rate. Once the permeate pressure is well below the saturated vapor pressure of feed, permeate pressure had a slightly negative effect on permeation performance by slightly reducing driving force. As the pressure approached the vapor pressure of feed, dehydration performances declined considerably due to the activity ratio of feed and permeate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.226-232
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• 2017

Surface pressure distributions over the RAE-A wing-body configuration were investigated and the grid convergence along the streamwise, spanwise, and circumferential directions was numerically studied. Flow analysis in subsonic and transonic conditions was conducted using the $k-{\omega}$ Wilcox-Durbin+ turbulence model. Surface pressure distributions for subsonic flows were well matched, but those for transonic shocked flows showed a little discrepancy with the experimental data. A cubic spline extrapolation method was applied in order to investigate the grid convergence. This method presented that the grid resolution in the circumferential direction is the most important grid parameter. A refined grid system was made based on the grid convergence study and provided more accurate prediction, especially on the symmetric body surface of RAE-A configuration.