• Title, Summary, Keyword: STL

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Evaluation of Sound Insulation Performance of a Unit Cabin Mock-up (유니트 캐빈 목업(mock-up)의 차음성능평가)

  • Kim, Hyun-Sil;Kim, Sang-Ryul;Kim, Bong-Ki;Kim, Jae-Seung;Lee, Sung-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.1
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    • pp.49-55
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    • 2011
  • Sound insulation performance of a unit cabin mock-up is studied, where two identical rooms simulating cruise ship cabin are installed. STL (Sound Transmission Loss) measurement in the mock-up shows that STL of the partition between rooms is degraded by imperfect door ceiling and gap between wall and floor. It is also observed that gap around lighting and electrical outlet slightly affect the STL in high frequency ranges, since lighting and electrical outlet are supported by mineral wool in the back side due to fire-resistance requirement. Even after all possible gaps are sealed, STL of the partition is found to be lower than that measured in the laboratory by 9 dB. Measurement of SBN (Structure-Borne Noise) reveals that flanking transmission of SBN along the steel deck floor can severely deteriorate STL of the partition. Statistical energy analysis (SEA) of the mock-up confirms importance of the floor SBN control, in which increasing damping is essential to ensure high STL.

A study on the sound transmission through double plates installed inside an impedance tube (임피던스 튜브 내에 설치된 이중 평판의 음파투과연구)

  • Kim, Hyun-Sil;Kim, Bong-Ki;Kim, Sang-Ryul;Seo, Yun-Ho;Ma, Pyung-Sik
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.4
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    • pp.253-260
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    • 2016
  • In this paper, derivation of the STL (Sound Transmission Loss) of the double plates installed in an impedance tube is discussed using an analytic method, where an air cavity exists between the plates. Vibration of the plates and sound pressure field inside the tube are expressed in terms of infinite series of modal functions. Under the plane wave assumption, it is shown that consideration of the first few modes yields sufficiently accurate results, and locations of peaks and dips are investigated. It is determined that the peak frequencies of the double plates coincide with those of each single plate. When the two plates are identical, the STL of the double plates as well as that of the single plate become zero at the natural frequencies of the single plate. The location and amplitude of the dips are investigated using an approximation solution when the cavity depth is very small.

Comparative study of two CAD software programs on consistency between custom abutment design and the output (두 가지 CAD software의 맞춤형 지대주 디자인과 출력물 일치도 비교)

  • Lim, Hyun-Mi;Lee, Kyu-Bok;Lee, Wan-Sun;Son, KeunBaDa
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.3
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    • pp.157-166
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    • 2018
  • Purpose: This study was aimed to compare the consistency between the custom abutment design and the output in two CAD software programs. Materials and Methods: Customized abutments were designed by using 3Shape Dental System CAD software and Delta9 CAD software on a plaster model with implants (CRM STL file). After milling of the designed abutments, the abutments were scanned with a contact method scanner (Test STL file). We overlaid the Test STL file with each CRM STL file by using inspection software, and then compared the milling reproducibility by measuring the output error of the specimens from each CAD software program. Results: The Delta9 showed better milling reproducibility than 3Shape when comparing the milling errors obtained with a full scan of all specimens (P < .05) and also when comparing the axial wall region specifically according to the axial angle. With 0.9 mm marginal radius, the Delta9 showed better consistency between the design and the output than 3Shape (P < .05). While, anti-rotation form had no significant difference in error between the two systems. When cumulative errors were compared, the Delta9 showed better milling reproducibility in almost cases (P < .05). Conclusion: Delta9 showed a significantly smaller error for most of the abutment design options. This means that it is possible to facilitate generation of printouts with reliable reproducibility and high precision with respect to the planned design.

Effect of the Extracts from the Leaves and Branches of Sageretia thea on β-catenin Proteasomal Degradation in Human Colorectal and Lung Cancer Cells (상동나무(Sageretia thea) 잎과 가지추출물의 대장암과 폐암세포의 β-catenin 분해 유도 활성)

  • Kim, Ha Na;Park, Gwang Hun;Kim, Jeong Dong;Park, Su Bin;Eo, Hyun Ji;Jeong, Jin Boo
    • 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.

Synergistic antitumor activity of ST1571 and camptothecin in human cancer cells (Camptothecin 에 의한 ST1571 의 항암 활성 증강)

  • Kim, Mi-Ju;Lee, Sang-Min;Bae, Jae-Ho;Chung, Byung-Seon;Kang, Chi-Dug;Kim, Sun-Hee
    • Journal of Life Science
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    • v.17 no.6
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    • pp.748-755
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    • 2007
  • The in vitro activity of ST1571, an inhibitor of the Abl group of protein-tyrosine kinases, alone or in combination with camptothecin (CPT), a specific topoisomerase I inhibitor, was evaluated against human cancer cells with different metastatic capacity and drug resistance potency. These cell lines showed different sensitivity to ST157 on growth inhibition, and the expression of DNA-dependent protein kinase (DNA-PK), which interacts constitutively with c-Abl, was significantly decreased in drug sensitive CEM and MCF-7 cells and poorly metastatic PC3 and KMl2 cells as compared with that of multidrug resistant CEM/MDR and MCF-7/MDR cells and highly metastatic PC3-MM2 and KM/L4a cells, respectively. These results suggest differential modulation of DNA-PK by ST1571 treatment in drug resistance and metastatic degree dependent manner. We showed that CPT as well as ST1571 significantly inhibits the expression of DNA-PK. The combined treatment with ST15fl and CPT revealed synergistic effect, and the effect was accompanied by inhibition of cell proliferation due to significant reduced expression of DNA-PK components, which resulted in CPT sensitizes human cancer cells resistant to ST1571. Therefore, the results of our study suggested that the suppression of DNA-PK using combination of ST1571 and CPT could be a novel molecular target for against drugresistant and metastatic cancer cells.

STL Generation in Reverse Engineering by Delaunay Triangulation (역공학에서의 Delaunay 삼각형 분할에 의한 STL 파일 생성)

  • Lee, Seok-Hui;Kim, Ho-Chan;Heo, Seong-Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.5
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    • pp.803-812
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    • 2002
  • Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and the measurement of clay or wood models for the development of new products. To generate a surface from measured points by a laser scanner, typical steps include the scanning of a clay or wood model and the generation of manufacturing data like STL file. A laser scanner has a great potential to get geometrical data of a model for its fast measuring speed and higher precision. The data from a laser scanner are composed of many line stripes of points. A new approach to remove point data with Delaunay triangulation is introduced to deal with problems during reverse engineering process. The selection of group of triangles to be triangulated based on the angle between triangles is used for robust and reliable implementation of Delaunay triangulation as preliminary steps. Developed software enables the user to specify the criteria for the selection of group of triangles either by the angle between triangles or the percentage of triangles reduced. The time and error for handling point data during modelling process can be reduced and thus RP models with accuracy will be helpful to automated process.

A Study on the Performance Comparison of 3D File Formats on the Web

  • Lee, Geon-hee;Choi, Pyeong-ho;Nam, Jeong-hwan;Han, Hwa-seop;Lee, Seung-hyun;Kwon, Soon-chul
    • 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.

Prediction Model of the Sound Transmission Loss of Honeycomb Panels for Railway Vehicles (철도차량용 허니콤재의 차음성능 예측모델)

  • Kim, Seock-Hyun;Paek, In-Su;Lee, Hyun-Woo;Kim, Jeong-Tae
    • 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.

The reliability evaluation of the analysis software for short-circuit test (대전력시험 분석프로그램의 신뢰성 평가)

  • Lee, Dong-Jun;Roh, Chang-ll;Jung, Heung-Soo;Kim, Sun-Koo;Kim, Won-Man;La, Dae-Ryeol;Kim, Chul-Hwan
    • Proceedings of the KIEE Conference
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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.

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A Study on 3D File Format for Web-based Scientific Visualization

  • Lee, Geon-hee;Nam, Jeong-hwan;Han, Hwa-seop;Kwon, Soon-chul
    • 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.