• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.382-384
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• 2021

In this study, we implement a system that automatically classifies types of plastics using YOLO (You Only Look Once), a real-time object recognition algorithm. The system consists of Nvidia jetson nano, a small computer for deep learning and computer vision, with model trained to recognize plastic separation emission marks using YOLO. Using a webcam, recycling marks of plastic waste were recognized as PET, HDPE, and PP, and motors were adjusted to be classified according to the type. By implementing this automatic classifier, it is convenient in that it can reduce the labor of separating and discharging plastic separation marks by humans and increase the efficiency of recycling through accurate recycling.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.766-771
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• 2012

PC (polycarbonate) is one of the widely used engineering plastics. Polycarbonate (PC) is traditionally produced by the reaction of phosgene and bisphenol-A. This phosgene process has the disadvantage as the high toxicity and corrosiveness of phosgene. The main point of focus to overcome the disadvantage of phosgene based process has been a route through dimethyl carbonate (DMC) to diphenyl carbonate (DPC). In this paper, for the DPC synthesis reaction using PBO as a catalyst, the effect of reaction temperature, reactant ratio, catalyst concentration on the reaction yield was investigated. A kinetic model for the DPC synthesis reaction was proposed and kinetic parameters for the proposed model was determined from batch reactor experiments. The predicted results by the proposed model were in good agreement with the experimental results.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.755-767
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• 2014

Chlorine is one of the most produced and most used non-flammable chemical substances in the world even though its toxicity and high reactivity cause the ozone layer depletion. However, in modern life, it is impossible to live a good life without using Chlorine and its derivatives since they are being used as an typical ingredient in more than 40 percent of the manufactured goods including medicines, detergents, deodorant, fungicides, herbicides, insecticides, and plastic, etc. Even if Chlorine has been handled and distributed in various business (small and medium-sized businesses, water purification plants, distribution company, etc.), there have been few researches about its possible health hazard and transportation risks. Accordingly, the purpose of this paper is to make a detailed assessment of Chlorine-related risks and to model an index of chemicals transportation risks that is adequate for domestic circumstances. The assessment of possible health hazard and transportation risks was made on 13 kinds of hazardous chemicals, including liquid chlorine. This research may be contributed to standardizing the risk assessment of Chlorine and other hazardous chemicals by using an index of transportation risks.

• New & Renewable Energy
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• v.18 no.4
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• pp.12-21
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• 2022

The pyrolysis characteristics of high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) were analyzed numerically using a 1D plug flow reactor (PFR) model. A lumped kinetic model was selected to simplify the pyrolysis products as wax, oil, and gas. The simulation was performed in the 400-600℃ range, and the plastic pyrolysis and product generation characteristics with respect to time were compared at various temperatures. It was found that plastic pyrolysis accelerates rapidly as the temperature rises. The amounts of the pyrolysis products wax and oil increase and then decrease with time, whereas the amount of gas produced increases continuously. In LDPE pyrolysis, the pyrolysis time was longer than that observed for other plastics at a specified temperature, and the amount of wax generated was the greatest. The maximum mass fraction of oil was obtained in the order of HDPE, PP, and LDPE at a specified temperature, and it decreased with temperature. Although the 1D model adopted in this study has a limitation in that it does not include material transport and heat transfer phenomena, the qualitative results presented herein could provide base data regarding various types of plastic pyrolysis to predict the product characteristics. These results can in turn be used when designing pyrolysis reactors.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1031-1036
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• 2006

햅틱 분야는 디스플레이 되는 콘텐츠를 만질 수 있게 촉감을 제공함으로써 의학, 교육, 군사, 방송 분야 등에서 널리 연구되고 있다. 이미 의학 분야에서는 Reachin 사(社)의 복강경 수술 훈련 소프트웨어와 같이 실제 수술 할 때와 같은 힘을 느끼면서 수술 과정을 훈련할 수 있는 제품이 상용화 되어 있다. 그러나 햅틱 분야가 사용자에게 시청각 정보와 더불어 추가적인 촉감을 제공함으로써 보다 실감 있고 자연스러운 상호작용을 제공하는 장점을 가진 것에 비해 아직은 일반 사용자들에게 생소한 분야다. 그 이유 중 하나로 촉감 상호작용이 가능한 콘텐츠의 부재를 들 수 있다. 일반적으로 촉감 콘텐츠는 컴퓨터 그래픽스 모델로 이루어져 있어 일반 그래픽 모델러를 사용하여 콘텐츠를 생성하나 촉감과 관련된 정보는 콘텐츠를 생성하고 나서 파일에 수작업으로 넣어주거나 각각의 어플리케이션마다 직접 프로그램을 해주어야 한다. 이는 그래픽 모델링과 촉감 모델링이 동시에 진행되지 않기 때문에 발생하는 문제로 촉감 콘텐츠를 만드는데 시간이 많이 소요되고 촉감 정보를 추가하는 작업이 직관적이지 못하다. 그래픽 모델링의 경우 눈으로 보면서 콘텐츠를 손으로 조작할 수 있으나 촉감 모델링의 경우 손으로 촉감을 느끼면서 동시에 조작도 해야 하기 때문에 이에 따른 인터페이스가 필요하다. 본 논문에서는 촉감 상호작용이 가능한 촉감 콘텐츠를 직관적으로 생성하고 조작할 수 있게 하는 촉감 모델러를 기술한다. 촉감 모델러에서 사용자는 3 자유도 촉감 장치를 사용하여 3 차원의 콘텐츠를 실시간으로 만져보면서 생성, 조작할 수 있고 촉감 사용자 인터페이스를 통해서 콘텐츠의 표면 촉감 특성을 직관적으로 편집할 수 있다. 촉감 사용자 인터페이스는 마우스로 조작하는 기존의 2차원 그래픽 사용자 인터페이스와는 다르게 3 차원으로 구성되어 있고 촉감 장치로 조작할 수 있는 버튼, 라디오 버튼, 슬라이더, 조이스틱의 구성요소로 이루어져 있다. 사용자는 각각의 구성요소를 조작하여 콘텐츠의 표면 촉감 특성 값을 바꾸고 촉감 사용자 인터페이스의 한 부분을 만져 그 촉감을 실시간으로 느껴봄으로써 직관적으로 특성 값을 정할 수 있다. 또한, XML 기반의 파일 포맷을 제공함으로써 생성된 콘텐츠를 저장할 수 있고 저장된 콘텐츠를 불러오거나 다른 콘텐츠에 추가할 수 있다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.81-93
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• 2020

The fatigue characteristics of glass fiber reinforced plastic (GFRP) composites were studied under repeated loads using the finite element method (FEM). To realize the material characteristics of GFRP composites, Digimat, a mean-field homogenization tool, was employed. Additionally, the micro-structures and material models of GFRP composites were defined with it to predict the fatigue behavior of composites more realistically. Specifically, the fatigue characteristics of polybutylene terephthalate with short fiber fractions of 30wt% were investigated with respect to fiber orientation, stress ratio, and thickness. The injection analysis was conducted using Moldflow software to obtain the information on fiber orientations. It was mapped over FEM concerned with fatigue specimens. LS-DYNA, a typical finite element commercial software, was used in the coupled analysis of Digimat to calculate the stress amplitude of composites. FEMFAT software consisting of various numerical material models was used to predict the fatigue life. The results of coupled analysis of linear and nonlinear material models of Digimat were analyzed to identify the fatigue characteristics of GFRP composites using FEMFAT. Neuber's rule was applied to the linear material model to analyze the fatigue behavior in LCF regimen. Additionally, to evaluate the morphological and mechanical structure of GFRP composites, the coupled and fatigue analysis were conducted in terms of thickness.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.263-273
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• 2015

We estimated the global inflow and stock of plastic marine debris. In South Korea, we estimated that the annual inflow of plastic marine debris (72,956 tons) was about 1.4% of annual plastics consumption (5.2 million tons) in 2012. By applying this 1.4% ratio to global plastics production from 1950 to 2013, we estimated that 4.2 million tons of plastic debris entered the ocean in 2013 and that there is a stock of 86 million tons of plastic marine debris as of the end of 2013, assuming zero outflow. In addition, with a logistic model, if 4% of petroleum is turned into plastics, the final stock of plastic marine debris shall be 199 million tons at the end. As the inflow and the stock are different units of measurement, better indicators to assess the effectiveness of inflow-reducing policies are needed. And, as the pollution from plastic marine debris is almost irreversible, countermeasures to prevent it should be valued more, and stronger preventive measures should be taken under the precautionary principle. As this is a preliminary study based on limited information, further research is needed to clarify the tendency of inflow and stock of plastic marine debris.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.269-280
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• 1998

Recently, application of composite materials such as fiber reinforced concretes(FRCs) and fiber reinforced plastics(FRPs) in conjunction with conventional structural components has become one of the main research areas. A proper use of advanced composite materials requires understanding their resistance mechanism and failure mode when they are applied to structures or their components. Particular considerations are given in this research to develop an analytical model which can predict the nonlinear flexural responses of bonded and unbonded prestressed concrete beams possibly having layers of different cementitious composite matrices in a section and/or FRP tendons. The block concept is used, which can be regarded as an intermediate modeling method between the couple method with one block and the layered method with multiply sliced layers in a section. In order to find a particular deflection point of a beam under load, solutions to the 2N-variables are found numerically by using approximate N-force equilibrium equations and N-moment equilibirum equations. The model is shown to successfully predict the flexual behavior of variously reinforced bonded and unbonded prestressed concrete beams. The model is also successful in simulating a gradually increasing load after sudden drop inload resistance due to fracture of one or more FRP tendons. This feature is useful in tracing the overall load-deflection response of a beam prestressed with brittle FRP tendons.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.373-378
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• 2007

최근 들어 햅틱 분야는 디지털 콘텐츠를 만질 수 있게 촉감을 제공함으로써 의학, 교육, 군사, 엔터테인먼트, 방송 분야 등에서 널리 연구되고 있다. 그러나 햅틱 분야가 사용자에게 시청각 정보와 더불어 추가적인 촉감을 제공함으로써 보다 실감 있고 자연스러운 상호작용을 제공하는 등 여러 가지 장점을 가진 것에 비해 아직은 일반 사용자들에게 생소한 분야다. 그 이유 중 하나로 촉감 상호작용이 가능한 콘텐츠의 부재를 들 수 있다. 또한 최근에 가상환경(Virtual Environment, VR)에 관심이 증가 되고, 가상환경에 햅틱이라는 기술을 접목시키는 시도가 많이 일어나고 있어서, 촉감 모델링에 대한 욕구 또한 증대 되고 있다. 일반적으로 촉감 모델링은 Material properties를 가지고 있는 그래픽 모델들로 구성이 된다. 그래픽 모델링은 일반적인 모델링툴 (MAYA, 3D MAX, 기타 등)으로 할 수 있다. 하지만 촉감 관련된 촉감 모델들은 콘텐츠를 제작한 이후에 일일이 수작업으로 넣어 주어야 한다. 그래픽 모델링에서는 사용자가 직접 눈으로 확인 하면서 작업을 이루어 지기 때문에 직관적으로 이루어질 수 있다. 이와 비슷하게 촉감 모델링은 직관적인 모델링을 하기 위해서 사용자가 직접 촉감을 느껴 보면서 진행이 되어야 한다. 또한 그래픽 모델링과 촉감 모델링이 동시에 진행이 되지 않기 때문에 촉감 콘텐츠를 만드는데 시간이 많이 걸리게 되고 직관적이지 못하는 단점이 있다. 더 나아가서 이런 촉감 모델링을 포함한 모델링 높은 생산성을 위해서 신속히 이루어져야 한다. 이런 이유들 때문에 촉감 모델링을 위한 새로운 인터페이스가 필요하다. 본 논문에서는 촉감 상호작용이 가능한 촉감 콘텐츠를 직관적으로 생성하고 조작할 수 있게 하는 촉감 모델러를 기술한다. 촉감 모델러에서 사용자는 3 자유도 촉감 장치를 사용하여 3 차원의 콘텐츠 (정적 이거나 동적이거나 Deformation이 가능한 2D, 2.5D, 3D Scene)를 실시간으로 만져보면서 생성, 조작할 수 있는 촉감 사용자 인터페이스 (Haptic User Interface, HUI)를 통해서 콘텐츠의 표면 촉감 특성을 직관적으로 편집할 수 있다. 촉감 사용자인터페이스는 마우스로 조작하는 기존의 2 차원 그래픽 사용자 인터페이스를 포함하여 3 차원으로 사용자 인터페이스도 추가되어 있고 그 형태는 촉감 장치로 조작할 수 있는 버튼, 라디오버튼, 슬라이더, 조이스틱의 구성요소로 이루어져있다. 사용자는 각각의 구성요소를 조작하여 콘텐츠의 표면 촉감 특성 값을 바꾸고 촉감 사용자 인터페이스의 한 부분을 만져 그 촉감을 실시간으로 느껴봄으로써 직관적으로 특성 값을 정할 수 있다. 또한, XML 기반의 파일포맷을 제공함으로써 생성된 콘텐츠를 저장할 수 있고 저장된 콘텐츠를 불러오거나 다른 콘텐츠에 추가할 수 있다. 이러한 시스템은 햅틱이라는 분야를 잘 모르는 사람들도 직관적으로 촉감 모델링을 하는데 큰 도움을 줄 수 있을 것이다.

• Composites Research
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• v.29 no.6
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• pp.342-346
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• 2016

Carbon fiber reinforced plastic (CFRP), one of lightweight materials, is the fiber structure using carbon fiber. It is the composite material that has the characteristics of carbon and plastic. As for the fiber structure, it has the great strength due to fiber direction. CFRP for woven type is used mostly as such a CFRP with lightweight. Woven type is more stable when compared with unidirectional type. On the other hand, woven type is highly priced. Therefore, this study aims to analyze the fiber structure of unidirectional CFRP. In this study, as the stacking angle [0/X/-X/0], X is the variable. This is unidirectional CFRP in which the angle phase of X has been reversed and stacked. By using such a unidirectional CFRP, the analysis model which had a crack at the center as the form of panel with the thickness of 2 mm was used. On analysis, the load is applied on the upper and lower parts being connected with a pin. The damage in the area near center crack was investigated. As for the analysis model, 3D surface model was designed by using CATIA. For CFRP stacking, the stacking direction was determined by using ACP in ANSYS program and the analysis model with two stacks was made. Afterwards, the structural analysis was carried out.