• Journal of Broadcast Engineering
• /
• v.26 no.3
• /
• pp.327-330
• /
• 2021

In this paper, a new noise filling method is proposed for improving the performance of the 3D audio codec. In the new method, the core band is limited up to MAX_SFB, not up to the IGF start frequency. And the noise filling is applied to all frequency range of the IGF source patches. We conduct the MUSHRA test and find that the proposed noise filling method demonstrates better performance than the conventional method.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.6
• /
• pp.384-390
• /
• 2015

There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2006.10a
• /
• pp.77-77
• /
• 2006

• Korean Journal of Remote Sensing
• /
• v.38 no.5_3
• /
• pp.953-966
• /
• 2022

Since aerosols adversely affect human health, such as deteriorating air quality, quantitative observation of the distribution and characteristics of aerosols is essential. Recently, satellite-based Aerosol Optical Depth (AOD) data is used in various studies as periodic and quantitative information acquisition means on the global scale, but optical sensor-based satellite AOD images are missing in some areas with cloud conditions. In this study, we produced gap-free GeoKompsat 2A (GK-2A) Advanced Meteorological Imager (AMI) AOD hourly images after generating a Random Forest based gap-filling model using grid meteorological and geographic elements as input variables. The accuracy of the model is Mean Bias Error (MBE) of -0.002 and Root Mean Square Error (RMSE) of 0.145, which is higher than the target accuracy of the original data and considering that the target object is an atmospheric variable with Correlation Coefficient (CC) of 0.714, it is a model with sufficient explanatory power. The high temporal resolution of geostationary satellites is suitable for diurnal variation observation and is an important model for other research such as input for atmospheric correction, estimation of ground PM, analysis of small fires or pollutants.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.4
• /
• pp.109-118
• /
• 2012

Large number of part design for aircraft and automobile is preceded by functional or sectional design groups for efficiency. However, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. These interferences and gaps cause design changes and additional repair processes. While interference problem has been resolved by digital mockup and concurrent engineering methodology, gap problem has been covered by temporary treatment of filling gap with sealant. This kind of fast fix causes fatal problem of leakage when the gap is too big for filling or the treatment gets old. With this research, we have developed a program to find the gap automatically among parts of assembly so that users can find them to correct their design before manufacturing stage. By using decomposition model representation method, the developed program can search the gap among complex car body parts to be visualized with volumetric information. It can also define the boundary between the gap and exterior empty space automatically. Though we have proved the efficiency of the developed program by applying to automobile assembly, application of the program is not limited to car body only, but also can be extended to aircraft and ship design of large number of parts.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10c
• /
• pp.674-676
• /
• 1998

소자가 sub-quarter um급으로 축소됨에 따라 STI(Shallow Trench Isolation) 기술은 고 집적도의 ULSI 구현에 있어서 중요한 격리 방법으로 많이 사용되고 있다. 현재의 STI 기술은 주로 실리콘 기판을 식각 후 절연물질로 빈 공백이 없이 채우는 (void-free gap filling) 방법 [1,2]과 절연물질을 다시 표면 근처까지 CMP(Chemical Mechnical Polishing)로 etchback하여 평탄화를 하는 방법이 주요한 기술이 되고 있다. 또한 STI 구조로된 격리구조에서 만들어진 MOSFET의 전기적인 특성은 트랜치 격리의 상부 부분의 형태와 gap-filling 물질에 따라 큰 영향을 받게된다. 따라서 본 논문에서는 STI 구조로 만들어진 격리 구조에서 MOSFET의 hump 특성에 관해 연구하였다. 그 결과 hump는 STI 모서리에서 필드 옥사이드의 recess에 의한 모서리 부분에서의 전계 집중과 boron의 segration에 기인한 농도 감소로 인해 hump가 발생하는 것으로 나타났다.

• The Journal of the Korean dental association
• /
• v.54 no.11
• /
• pp.865-873
• /
• 2016

Background/Purpose: The purpose of this study was to evaluate the effect of Nd:YAG irradiation on adherence of retrograde filling materials (mineral trioxide aggregate [MTA] and Super-EBA) by micro-computed tomography (CT) measurement and to observe the dentinal surface after irradiation by scanning electron microscopy (SEM). Materials and methods: Forty retrofilling models using extracted human teeth were divided into four groups according to the material and method used: ProRoot MTA (MTA group), Super-EBA (EBA group), MTA with Nd:YAG laser irradiation (LMTA group), and Super-EBA with Nd:YAG laser irradiation (LEBA group). All specimens were stored in 100% humidity for 24 hours until micro-CT was performed. The gap volume of the tooth/material interface was measured using the CTAn program. In six samples, the laser-irradiated dentin surface was observed using SEM. Results: The mean percent difference in gap volume was not statistically significant between the Nd:YAG laser-irradiated groups and non-irradiated in both materials(P > 0.05). The gap volume in the MTA group was significantly lower than that in the EBA group (P < 0.05). Examination of the non-irradiated specimens by SEM showed patent dentinal tubules. In contrast, alterations in the texture of the dentin surface and obliteration of the dentinal tubules were evident in the Nd:YAG laser-irradiated specimens. Conclusion: In this study, changes in the dentinal surface after Nd:YAG irradiation did not affect adherence between the apical filling material and the dentin wall.

• The Korean Journal of Pesticide Science
• /
• v.19 no.1
• /
• pp.14-21
• /
• 2015

To determine residual characteristics of azoxystrobin in ginseng under different cultivation conditions such as use of straw mat on cultivation soil and filling gap between ginseng stem and soil surface and also to elucidate its approximate behavior after spraying, 20% azoxystrobin suspension concentrate solution was sprayed 4 times onto 5-year-old ginseng with 10 days interval at a application rate of about 200 L/10 a and then residues in samples were analyzed. The residue level was lower in case of use of straw mat and filling the gap with soil than in case of no use of straw mat and no filling the gap, representing that use of straw mat and filling the gap with soil were contributed to decrease of pesticide residues in ginseng. A large portion of the test pesticide distributed onto ginseng leaf with a higher specific surface area. The amounts of azoxystrobin residues decreased in ginseng leaf, while increased on soil surface, as close to harvest. About 0.1% of azoxystrobin sprayed was distributed in ginseng root and 12.7-20.4% (mean 16.6%) of azoxystrobin could be decreased for dietary intake by removing of rhizome from ginseng root before intake.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.950-955
• /
• 2005

This paper describes an intelligent filler wire feeding device which can control 3- dimensional seam tracking and the filler wire speed by measuring the gap position and the joint gap width in laser welding. By means of visual sensor controlled filling the missing material into the joint gap and 3 dimensional seam tracking, lineup errors from manufacturing tolerances and the repeatability of lineup jigs and weld robot can be balanced and at an even seam quality which avoids weld defects. In this paper, we assessed weld quality in 2mm sheets of A16061 which had various gap width by using the intelligent filler wire feeding device.

• Korean Journal of Construction Engineering and Management
• /
• v.10 no.6
• /
• pp.40-47
• /
• 2009

The lightweight bubble mixture soil is used for soft ground rear-filling material by applying reduced weight on structure. However, comparing with the general soil, it is not applied in domestic because of initial phase cost of construction. General soil, which has lower initial phase cost is usually used for rear-filling, but the use of overlay method of general soil is reduced as the number of layers increases. Especially box structure placed in soft ground or the overlay method when gap near pier rear-filling can be replaced with temporary alternative method, however, it can't be a solution to gap by generation of extra weight of thickness of overlaying. Therefore, execute LCC analysis of two alternative-the general and the lightweight bubble mixture soils, which are rear-filling material of box structure- and present economical analysis in order to make resonable decision from the economics. As a result, although the lightweight bubble mixture soil takes higher initial phase cost than the general soil, it has been analyzed to procure economical efficiency by having less cost of maintenance.