• The Journal of the Acoustical Society of Korea
• /
• v.15 no.2E
• /
• pp.45-49
• /
• 1996

From the reverberation signals received in the shallower water, the surface scattered signals are identified by using the multipath eigneray model that provides launch angles, grazing angles and transmission loss from the high frequency directional source to and from the rough surface. For small scale surface waves, the perturbation method is used to compute the backscattering strength for various grazing angles and wind speeds. A scheme to inversely estimate the wind speed, by which the observed surface reverberation levels are produced, has been tested. In result, for low grazing angles the perturbation method can be used to predict the backscattering stregth, thereby the surface wind can be indirectly estimated.

• Journal of Korean Society for Atmospheric Environment
• /
• v.13 no.3
• /
• pp.231-241
• /
• 1997

A tracer model was applied in the Far East Asia to investigate the dry deposition rates of air pollutants on Korean Peninsula originated from different countries including China and Japan. Wind direction was chosen to predict the maximum deposition rates and SO$_2$ was chosen as a tracer to estimate the source strength. Model simulation shows that inflow, deposition and airborne ratios of China-originated SO$_2$ were 50%, 8% and 30%, respectively, at most. Also it was found that deposition, outbounded and airborne ratios of Korea-originated SO$_2$ were 15~77%, 8~75%, and 3~30%, respectively Model simulation also shows that inflow, deposition and airborne ratios of Kyushu-originated SO$_2$ were, 30~45%, 8~14％ and 20~25%, respectively. This study shows that tracer model can be applied on the estimation of air pollutants partitioning in regional scale and that more sophisticated modules and schemes can be developed and applied to better predict the transboundary amounts of air pollutants in this region.

• Journal of Internet Computing and Services
• /
• v.23 no.3
• /
• pp.13-20
• /
• 2022

IEEE 802.11ay Wi-Fi is the next generation wireless technology and operates in mmWave band. It supports the MU-MIMO (Multiple User Multiple Input Multiple Output) transmission in which an AP (Access Point) can transmit multiple data streams simultaneously to multiple STAs (Stations). To this end, the AP should perform MU-MIMO beamforming training with the STAs. For efficient MU-MIMO beamforming training, it is important for the AP to estimate signal strength measured at each STA at which multiple beams are used simultaneously. Therefore, in the paper, we propose a deep learning-based link quality estimation scheme. Our proposed scheme estimates the signal strength with high accuracy by utilizing a deep learning model pre-trained for a certain indoor or outdoor propagation scenario. Specifically, to estimate the signal strength of the multiple concurrent beams, our scheme uses the signal strengths of the respective single beams, which can be obtained without additional signaling overhead, as the input of the deep learning model. For performance evaluation, we utilized a Q-D (Quasi-Deterministic) Channel Realization open source software and extensive channel measurement campaigns were conducted with NIST (National Institute of Standards and Technology) to implement the millimeter wave (mmWave) channel. Our simulation results demonstrate that our proposed scheme outperforms comparison schemes in terms of the accuracy of the signal strength estimation.

• Journal of the Korean housing association
• /
• v.17 no.3
• /
• pp.61-69
• /
• 2006

Vertical vibrations on the slab of buildings are affected by types of vibration sources, transfer paths, and the material property and the size of members. Among these parameters, the vibration sources and the transfer path can not be controlled, but the property and the size of members can be controlled in the phase of design the members. In this study, the vibration responses according to the property and size of members were obtained by using a prediction program based on dynamic-stiffness matrix. Three parameters which are not usually considered as major factors for architecral planning were selected fur these analyses. They are the strength of materials, the thickness of wall and the thickness of slab. The ground vibration source located near a building was used as vibration input data in the analyses. This study has its originality on presenting appropriate property and size of structural members in order to reduce vertical vibration of slab in shear-wall structures. Analysing the results from the vibration estimation program according to the variations of parameters, the appropriate ratio among the sizes of structural members were proposed. From these results, the vibration level on the slab which is not constructed yet would be predicted and the vibration peak level can be reduced or shifted into the desirable frequency range. Therefore, the vertical vibration could be controlled in the phase of designing buildings.

• Fashion & Textile Research Journal
• /
• v.15 no.4
• /
• pp.635-641
• /
• 2013

This study examined the dye-properties of natural fabrics dyed with Coptis chinensis and Curcuma longa root fermented with fungi. The optimum culture conditions for the fermentation of microorganisms, the relationship between natural dye color and fermentation conditions were investigated. Two different medical herbs (ground to 80-100 mesh in size) were used as a natural dyeing source. Phellinus linteus (P. linteus), which can grow in different media, such as Agarmedium (only agar containing medium), maltose extract agar (MA) and potato dextrose extract agar (PDA) culture media, were isolated from the medium. P. linteus was confirmed to be the optimum microorganism for the fermentation of Coptis chinensis and Curcuma longa, and the MA medium was confirmed to be the best for culturing. When using the microorganism as the fermenting agent, $32^{\circ}C$ was found to be the optimum fermenting temperature for both natural colorants. Regarding the dyeing property of the fermented natural dye, silk was dyed quite darkly in an appearance by naked eye estimation and the K/S value in the color strength of silk reached a high level of 16 after the fermenting process. The washing fastness of dyed silk after treatment washing was reduced from 4 to under4 and indicates that dyed silk with fermented plant was not unsubstantial. The light fastness was 1 to 2, showing intended to maintain due to the fermentation process.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.5
• /
• pp.3169-3173
• /
• 2013

Background: Findings from previous published studies regarding the association of the XRCC3 Thr241Met polymorphism with glioma susceptibility have often been conflicting. Therefore, a meta-analysis including all available publications was carried out to make a more precise estimation of the potential relationship. Methods: By searching the electronic databases of Pubmed and Embase (up to April 1st, 2013), a total of nine case-control studies with 3,752 cases and 4,849 controls could be identified for inclusion in the current meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association. Results: This meta-analysis showed the XRCC3 Thr241Met polymorphism to be significantly associated with decreased glioma risk in the allelic model (Met allele vs. Thr allele: OR= 0.708, 95%CI= 0.631-0.795). Moreover, we also observed a statistically significant association between the XRCC3 Thr241Met polymorphism and reduced glioma risk in analyses stratified by ethnicity (Asian) and source of controls (hospital based) in the allelic model. Conclusions: Current evidence suggests that the XRCC3 Thr241Met polymorphism may be a risk factor for glioma development, especially in Asians.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.79.2-79.2
• /
• 2019

Based on three types of 2-point statistics (galaxy clustering, galaxy-galaxy lensing, and cosmic shear power spectra) from the Deep Lens Survey (DLS), we constrain cosmology and baryonic feedback. The DLS is a deep survey, so-called a precursor to LSST, reaching down to ~27th magnitude in BVRz' over 20 deg2. To measure the three power spectra, we choose two lens galaxy populations centered at z ~0.27 and 0.54 and two source galaxy populations centered at z ~0.64 and 1.1, with more than 1 million galaxies. We perform a number of consistency tests to confirm the reliability of the measurements. We calibrated photo-z estimation of the lens galaxies and validated the result with galaxy cross-correlation measurement. The B-mode signals, indicative of potential systematics, are found to be consistent with zero. The two cosmological results independently obtained from the cosmic shear and the galaxy clustering + galaxy-galaxy lensing measurements agree well with each other. Also, we verify that cosmological results between bright and faint sources are consistent. While there exist some weak lensing surveys showing a tension with Planck, the DLS constraint on S8 agrees nicely with the Planck result. Using the HMcode approach derived from the OWLS simulation, we constrain the strength of baryonic feedback. The DLS results hint at the possibility that the actual AGN feedback may be stronger than the one implemented in the current state-of-the-art simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.3
• /
• pp.296-303
• /
• 2014

In this paper, we propose an algorithm to visualize radio wave environment based on the measured Received Signal Strength Indication( RSSI) and 3D geographic information. We estimate the source position using the circumcenter of the triangle and visualize the radio wave environment using the empirical propagation models. A mode seeking algorithm(mean-shift clustering) is used to seek the peak points and the center of gravity is utilized to reduce the estimation errors. Our approach finds its applications in the radio wave monitoring systems for the efficient utilization of radio resources.

• Journal of the Korean earth science society
• /
• v.40 no.1
• /
• pp.46-55
• /
• 2019

In this study, we investigated the stone materials used in the Woldae of Kwanghwamun gate to estimate their provenances. The Woldae was partly reconstructed in 2010 using red-colored original stone and greyish new stone. We carried out geological survey in Mt. Bukhan (Bukhansan) and Mt. Surak (Suraksan) to estimate the source of stone, where red-colored granitic rocks are widely distributed. Though the petrographical features of the granitic rocks from the surveyed area are quite similar, there exists a slight variation of magnetic susceptibility and color index of the rocks: the granitic rocks from Mt. Surak have higher value of magnetic susceptibility and clearer reddish feature. A series of evidence, such as historical records, stone cutting traces and petrographical features, for the source of stone materials used in the Woldae tells that Mt. Surak would have been the provenance for the stone materials used in the Woldae. We also conducted a nondestructive test to examine the physical property of the rocks. The original stone shows low compressive strength (147 MPa) due to the weathering, whereas the rock in Mt. Surak has higher compressive strength (244 MPa) capable of being used as building materials. If there were any difficulties to use the granitic rocks in Mt. Surak, some granitic rocks that have similar petrological characteristics, such as Changsu stone and Yeongjung stone from the Pocheon area, could be used as building material instead.

• Journal of Environmental Science International
• /
• v.23 no.3
• /
• pp.511-520
• /
• 2014

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.