• Journal of the Korea Computer Graphics Society
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• v.24 no.4
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• pp.29-38
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• 2018

In this paper, we propose an automatic segmentation method of meniscus in knee MR images by automatic meniscus localization, multi-atlas-based locally-weighted voting, and patch-based edge feature classification. First, after segmenting the bone and knee articular cartilage, the volume of interest of the meniscus is automatically localized. Second, the meniscus is segmented by multi-atlas-based locally-weighted voting taking into account the weights of shape and intensity distribution in the volume of interest of the meniscus. Finally, to remove leakage to the collateral ligaments with similar intensity, meniscus is refined using patch-based edge feature classification considering shape and distance weights. Dice similarity coefficient between proposed method and manual segmentation were 80.13% of medial meniscus and 80.81 % for lateral meniscus, and showed better results of 7.25% for medial meniscus and 1.31% for lateral meniscus compared to the multi-atlas-based locally-weighted voting.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.121-126
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• 2017

A technique for producing the ear shell for a hearing aid using DICOM (Digital Imaging and Communication in Medicine) image and a 3D printing was studied. It is a new application method, and is an application technique that can improve the safety and infection of hearing aid users and can reduce the production time and process stages. In this study, the effects on the shape surface were examined before and after the printing of the ear shell using a 3D printer based on the values obtained from the raw data of the DICOM images at the volumes of 0.5 mm, 1.0 mm, and 2.0 mm, respectively. Before the printing, relative relationship was compared with respect to the STL (STereoLithography) file structure; and after the printing, the intervals of the layered structure of the ear shell shape surface were compared by magnifying them using a microscope. For the STL file structure, the numbers of triangular vertices, more than five intersecting points, and maximum intersecting points were large in the order of 0.5 mm, 1.0 mm, and 2.0 mm, respectively; and the triangular structure was densely distributed in the order of the bending, angle, and crest regions depending on the sinuosity of the external auditory meatus shape. As for the ear shell shape surface examined by the digital microscope, the interval of the layered structure was thick in the order of 2.0 mm, 1.0 mm, and 0.5 mm. For the STL surface structure mentioned above, the intersecting STL triangular structure was denser as the sinuosity of the 3D ear shell shape became more irregular and the volume of the raw data decreased.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.233-238
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• 1985

The non-porous and porous polystyrene divinylbenzene copolymers were prepared by the suspension polymerization method. The non-porous aminated polystyrene divinylbenzene, N-APSTDVB and the porous aminated polystyrene divinylbenzene, P-APSTDVB of 50∼100mesh size weakly basic anion exchanger were synthesized by chloromethylation followed by amination with methylamine. The functional groups of these synthesized anion exchangers were confirmed by their infrared spectra. The maximum capacity of these exchangers was 4.86meq/g. Pore volume and pore spectra were determined with a mercury porosimeter. The pore volume of P-PSTDVB increased with increasing X$_{diluent}$ at 30% of divinylbenzene. However, the pore volume of P-PSTDVB increased with increasing volume percent of divinylbenzene at constant mole fraction of diluent, X$_{diluent}$ of 0.5. The pore volume of synthesized copolymer and anion exchanger at 8% divinylbenzene and 0.5X$_{heptane}$ decreased as follows; P-PSTDVB 〉P-APSTDVB 〉N-PSTDVB. This result was attributed to the possibility that the pore volume were reduced by amination reactions. The distribution coefficients of boric acid on the N-APSTDVB anion exchanger in various concentrations of alcohol water solutions showed that as alcohol concentration increased, the distribution coefficients values decreased due to the reduced concentration of H$_2$BO$_3^-$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1581-1588
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• 2011

In this study, flow characteristics in a multi-cavity injection molding process were investigated. One of main problems occurred in the multi-cavity molding is a flow imbalance among cavities since it affects physical properties and quality of products. Charge imbalance is caused by the uneven shear stress. Therefore, changes in viscosity affect the physical properties of resin and injection conditions differ in the filling imbalance phenomenon. Through, this study focus on experimental studies of flow imbalance for PC and PP resin occurring in a balanced delivery system. Experimental results were compared with CAE results. By experimental and CAE analysis, main cause for the flow imbalance is temperature distribution in cross section of runner. New runner system with a simple change of runner shape was suggested to avoid the flow imbalance. A series of simulation to confirm feasibility of Volume Runner's effects was conducted using injection molding CAE.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.746-751
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• 2014

In this paper, ship performance prediction solver was developed using open source computational fluid dynamics (CFD) libraries. The mass- and momentum-conservation equations and turbulent model with a wall function for the turbulent closer were considered. The volume fraction transport equation with a high-resolution interface capturing scheme were selected for free-surface simulation. The predicted wave pattern around KRISO container ship (KCS) using developed program showed good agreement against existing experimental data. For the revolution of a propeller in the propulsive test, general grid interface (GGI) library was used. The predicted propulsive performance showed 7 % difference against experimental data. Two-phase mixture model was developed to simulate a cavitation and applied to a propeller. The sheet cavitation on the propeller was predicted well. From results, the potential of the numerical tank developed by open source libraries was verified by applying it to KCS.

• Journal of Industrial Convergence
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• v.21 no.7
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• pp.83-92
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• 2023

The bullet shape of the plasma jet using the atmospheric-pressure dielectric barrier discharge method changes depending on the applied fluid rate and the intensity of the electric field. This changes appear as a difference in spectral distribution due to a difference in density of the DBD plasma jet. It is an important factor in utilizing the plasma device that difference between the occurrence of active species and the intensity through the analysis of the spectrum of the generated plasma jet. In this paper, a plasma jet generator of the atmospheric pressure volume DBD method using Ar gas was make a prototype in accordance with the proposed design method. The characteristics jet fluid rate analysis of Ar gas was accomplished through simulation to determine the dependence of flow rate for the generation of plasma jets, and the characteristics of plasma jets using spectrometers were analyzed in the prototype system to generate optimal plasma jet bullet shapes through MFC flow control. Through the design method of the proposed system, the method of establishing the optimal plasma jet characteristics in the device and the results of active species on the EOS were verified.

• Progress in Medical Physics
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• v.25 no.4
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• pp.233-241
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• 2014

The aim of this study is to develop a new software tool for 3D dose verification using $PRESAGE^{REU}$ Gel dosimeter. The tool included following functions: importing 3D doses from treatment planning systems (TPS), importing 3D optical density (OD), converting ODs to doses, 3D registration between two volumetric data by translational and rotational transformations, and evaluation with 3D gamma index. To acquire correlation between ODs and doses, CT images of a $PRESAGE^{REU}$ Gel with cylindrical shape was acquired, and a volumetric modulated arc therapy (VMAT) plan was designed to give radiation doses from 1 Gy to 6 Gy to six disk-shaped virtual targets along z-axis. After the VMAT plan was delivered to the targets, 3D OD data were reconstructed from 512 projection data from $Vista^{TM}$ optical CT scanner (Modus Medical Devices Inc, Canada) per every 2 hours after irradiation. A curve for converting ODs to doses was derived by comparing TPS dose profile to OD profile along z-axis, and the 3D OD data were converted to the absorbed doses using the curve. Supra-linearity was observed between doses and ODs, and the ODs were decayed about 60% per 24 hours depending on their magnitudes. Measured doses from the $PRESAGE^{REU}$ Gel were well agreed with the TPS doses at central region, but large under-doses were observed at peripheral region at the cylindrical geometry. Gamma passing rate for 3D doses was 70.36% under the gamma criteria of 3% of dose difference and 3 mm of distance to agreement. The low passing rate was resulted from the mismatching of the refractive index between the PRESAGE gel and oil bath in the optical CT scanner. In conclusion, the developed software was useful for 3D dose verification from PRESAGE gel dosimetry, but further improvement of the Gel dosimetry system were required.

• Journal of KIISE:Software and Applications
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• v.36 no.12
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• pp.967-976
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• 2009

In this paper, we propose an automatic lower extremity vessel extraction based on rigid registration and bone elimination techniques in CT and CT angiography images. First, automatic partitioning of the lower extremity based on the anatomy is proposed to consider the local movement of the bone. Second, rigid registration based on distance map is performed to estimate the movement of the bone between CT and CT angiography images. Third, bone elimination and vessel masking techniques are proposed to remove bones in CT angiography image and to prevent the vessel near to bone from eroding. Fourth, post-processing based on vessel tracking is proposed to reduce the effect of misalignment and noises like a cartilage. For the evaluation of our method, we performed the visual inspection, accuracy measures and processing time. For visual inspection, the results of applying general subtraction, registered subtraction and proposed method are compared using volume rendering and maximum intensity projection. For accuracy evaluation, intensity distributions of CT angiography image, subtraction based method and proposed method are analyzed. Experimental result shows that bones are accurately eliminated and vessels are robustly extracted without the loss of other structure. The total processing time of thirteen patient datasets was 40 seconds on average.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.33-33
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• 2019

너도개미자리(Minuartia laricina (L.) Mattf.)는 석죽과 나도개미자리속 식물로 낭림산 이북부터 백두산까지 분포하며, 7~10월에 백색의 꽃이 아름답게 개화하여 관상 목적으로 이용된다. 본 연구는 너도개미자리를 관상식물로 활용하기 위한 효율적인 육묘 방법을 개발하기 위하여 수행되었다. 실험은 유용식물증식센터에서 분양받은 종자를 2019년 4월 19일에 트레이에 파종하여 6월 14일까지 충북대학교 첨단유리온실에서 8주 동안 육묘하였다. 파종용기에 따른 너도개미자리의 생육을 알아보기 위하여 162, 200, 288구 트레이를 이용하였다. 토양은 단용토로 원예상토를 사용하였으며, 혼용토는 피트모스와 펄라이트를 3:1, 4:1 비율로 혼합하여 진행되었다. 파종립수 실험은 200구 트레이의 셀당 각 1, 2, 4, 6립씩 파종하였으며, 차광 실험은 0, 55, 75%의 차광막이 설치된 육묘배드에서 실시하였다. 추비는 hyponex (6.5-6-19)를 처리별 각 0, 250, 500, $1000mg{\cdot}L^{-1}$의 농도로 출아 후 2, 4, 6주차에 총 3회 살포하였다. 대조구는 200구 트레이에 원예상토를 충진한 다음 셀당 1립씩 파종하여 차광을 하지 않은 온실에 배치하였으며, hyponex $500mg{\cdot}L^{-1}$를 처리하였다. 연구의 결과, 너도개미자리는 셀의 용량이 클수록 모든 생육이 양호한 결과를 보여, 162구 트레이에 육묘하는 것이 가장 효과적이었다. 토양 실험의 결과, 원예상토에서 생육이 양호하였으나, 피트모스와 펄라이트의 혼용토는 생육이 크게 억제되었다. 셀당 파종립수를 달리한 결과, 너도개미자리의 개체별 생육은 파종립수가 적을수록 유리하였으나, 본 연구의 목적인 관상적 가치를 위한 생육과 볼륨을 고려하였을 때 셀당 2립 파종묘가 효과적인 것으로 판단되었다. 추비 실험은 농도가 높을수록 생육이 왕성해지는 경향이었으며, $1000mg{\cdot}L^{-1}$에서 가장 효과적이었다. 차광 실험의 결과, 무차광 조건에서 전반적인 생육이 양호하였으며, 차광율이 높을수록 초장이 길어지는 경향이었다. 결론적으로, 너도개미자리의 육묘는 162구 트레이에 원예상토를 충진하고 셀당 종자를 2립 파종하여 무차광 조건에서 추비를 $1000mg{\cdot}L^{-1}$의 농도로 처리하며 육묘하는 것이 효과적일 것으로 판단된다.