• Korean Journal of Plant Resources
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• v.32 no.2
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• pp.153-159
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• 2019

In this study, we evaluated the effect of branch (STB) and leave (STL) extracts from Sageretia thea on ${\beta}-catenin$ level in human colorecal cancer cells, SW480 and lung cancer cells, A549. STB and STL dose-dependently suppressed the growth of SW480 and A549 cells. STB and STL decreased ${\beta}-catenin$ level in both protein and mRNA level. MG132 decreased the downregulation of ${\beta}-catenin$ protein level induced by STB and STL. However, the inhibition of $GSK3{\beta}$ by LiCl or ROS scavenging by NAC did not block the reduction of ${\beta}-catenin$ protein by STB and STL. Our results suggested that STB and STL may downregulate ${\beta}-catenin$ protein level independent on $GSK3{\beta}$ and ROS. Based on these findings, STB and STL may be a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer and lung cancer.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.624-626
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• 2005

디지털 컴퓨터와 측정시스템의 발달로 대전력시험 데이터들은 시험자에 의한 분석이 아닌, 분석프로그램을 이용한 자동 분석이 가능해 졌다. 그러나 분석 프로그램을 이용하여 시험데이터를 분석해야 할 경우, 분석프로그램의 객관적인 신뢰성이 먼저 확보되어야 한다. 최근 들어 이러한 문제점을 보완하기 위하여, STL(Short-circuit Testing Liason)에서는 분석프로그램의 신뢰성평가를 위해 TDG(Test Data Generator)를 개발하였다. 이를 이용하면 대전력시험기관에서 사용하는 분석프로그램간의 객관적인 비교 및 평가가 가능하다. 따라서 본 논문에서는 STL에서 배포한 TDG를 이용하여, Crest, RMS, %DC 분석프로그램 알고리즘의 신뢰성을 평가해 보았다. 또한, STL에서 제시한 reference curve는 50[Hz]를 기본주파수로 하고 있기 때문에, 평가의 신뢰성을 높이기 위해 본 논문에서는 우리나라의 실정에 맞는 60[Hz]의 reference curve도 추가로 고려하였다. 신뢰성 평가 결과 모든 reference curve에 대한 분석알고리즘의 측정불화도가 STL에서 제시하는 범위에 존재함을 확인하였다.

• Journal of the Korean Society for Railway
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• v.11 no.5
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• pp.465-470
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• 2008

Sound transmission characteristics are investigated on the honeycomb panels used for railway vehicles. Equivalent orthotropic plate model and equivalent mass law are applied to predict the sound transmission loss (STL) of the honeycomb panels. The predicted values of the STL are compared with the measured values. The reliability and the limitation of the prediction models are investigated. Coincidence effect and local resonance effect on STL are considered. The result of the study shows that the equivalent orthotropic plate model can be used as a good prediction model, if the local resonance frequency is properly applied. finally, ways to improve the severe STL drop by local resonance are proposed and the effect on the sound insulation performance is analysed.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.65-74
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• 2019

3D file formats typically include OBJ (Wavefront file format), STL (STereoLithography), and FBX (Filmbox). Each format has limitations depending on its configuration and usage, and supported formats are different depending on the software application. glTF helps uniform integration of 3D file formats and allows for more efficient transmission of large 3D geometry files by organizing them in a binary format. This paper presents explanation on OBJ, FBX, and STL which are major examples of existing 3D file formats. It also explains the concept and characteristics of glTF and compares its performance with other 3D file formats on the web. The loading time and packets of each 3D file format are measured according to the web browser environment by means of Google Chrome, Firefox and Microsoft Edge. Experimental results show that glTF is the most efficient and that it exhibits the best performance. As to STL, relatively excessive traffic was observed. This study is expected to contribute to reducing rendering time on the web as 3D file formats are used.

• International Journal of Advanced Culture Technology
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• v.7 no.1
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• pp.243-247
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• 2019

The most commonly used 3D modeling file formats are OBJ (Wavefront file format specification) and STL (STereoLithography). Although they have a common point of view in 3D on the screen, detailed functions are different according to purpose of development. OBJ is the most commonly used 3D file format and STL is mainly used as 3D file format for 3D printing. However, in the field of Scientific Visualization, precise analysis is required. There is a difference in accuracy depending on the type of 3D file format. OBJ and STL are not suitable for delicate surface description because they form meshes in the form of triangular polygons. And if you increase the number of triangle polygons, it will be smoother, but the file size also increases exponentially and causes excessive CPU usage. In contrast, VTK provides a variety of polygon structures, including triangular polygons as well as rectangular polygons and cube polygons. Thus, delicate surface depiction is possible. Delicate surface rendering is possible and file size is not large. This paper describes the concept and structure of VTK. We also compared the load times and file sizes between VTK, STL, and OBJ in the Chrome browser. In addition, the difference in surface rendering ability between VTK, STL, and OBJ is intuitively viewed based on the screen in which each 3D file format is implemented under the same conditions. This study is expected to be helpful for efficient 3D file format for precise implementation of Web - based Scientific Visualization.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.167-168
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• 2009

The noise sources in ship and offshore structure have an influence on adjacent receiving area through a partition between noise sources and receiving area. The partition in ship is usually made of stiffened plate. Sound transmission loss (STL) of the partition at high frequency could be improved by additional installation of insulation or wall panel. At low frequency, however, it is very difficult and needs an increase of plate thickness which causes a considerable weight increase of ship. In this paper, we have investigated the effect of the bulkhead boundary condition. From measurement result, we found that the bulkhead boundary condition can affect a lot in STL, especially at low frequency range. Finally, we get the 5dB increase in STL through the modification of boundary condition.

• Korean Journal of Computational Design and Engineering
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• v.6 no.1
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• pp.48-58
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• 2001

One of the biggest problems of rapid prototyping(RP) technologies lies in their standard file format for CAD data exchange. Current methods using the de facto industry standard 'STL'have at times resulted in problems such as accuracy, redundancy, and integrity. In this paper we propose a STEP based data exchange framework for rapid prototyping systems. In this paradigm of data exchange, STEP models can be imported and converted into faceted B-rep. solid models for visualization and 2-D layer data for RP. Also an STL model, on the other hand, can be converted into a faceted B-rep. STEP model and exported as a new data exchange model with RP information.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.293-297
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• 2004

This paper is described manufacturing to jewelry by using rapid prototype. At that time, the SLC file is useful for solved generating errors to part build file. Then. we have reduced the time of manufacturing complicated three-dimensional form. Generally, it is used the STL file for rapid prototype that it is necessary to considerable time when complicated firm as jewelry generated pan build file. But the SLC file is solved to problem because it consists of configuration of a section. Neter the less, Generating Part build file hate had a lot of problem when the SLC file is used.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.202-211
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• 2005

This paper introduces and illustrates the results of a new method fer offsetting triangular mesh by moving all vertices along the multiple normal vectors of a vertex. The multiple normal vectors of a vertex are set the same as the normal vectors of the faces surrounding the vertex, while the two vectors with the smallest difference are joined repeatedly until the difference is smaller than allowance. Offsetting with the multiple normal vectors of a vertex does not create a gap or overlap at the smooth edges, thereby making the mesh size uniform and the computation time short. In addition, this offsetting method is accurate at the sharp edges because the vertices are moved to the normal directions of faces and joined by the blend surface. The method is also useful for rapid prototyping and tool path generation if the triangular mesh is tessellated part of the solid models with curved surfaces and sharp edges. The suggested method and previous methods are implemented on a PC using C++ and illustrated using an OpenGL library.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.30-35
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• 2002

Nowadays, as the development period of new products becomes shorter and consumer's requirement is more various, the importance of Rapid Prototyping Technology has been rapidly increased. Rapid Prototyping makes prototypes or frictional parts directly using the 3D CAD data. But RP machines can make prototypes in limit size. For making large size prototype, we slice solid which is made of STL file, and then glue sliced solid. And if contact area of part is small, union solid will be easily destroyed for going down of adhesion. So we need to expand contact area, 1 suggest making a section into stair shape. This paper is concerned with slicing solid on STL file and improving on adhesion.