• ETRI Journal
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• v.35 no.6
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• pp.1148-1151
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• 2013

We propose a way to measure the absorber reflectivity at a low cost. Only one simple antenna with a small radiating aperture and a frequency-domain instrument are utilized. The previously used equation for calculating the reflectivity of an absorber is inaccurate, and, therefore, a new equation is derived based on multiple reflection analysis and three test models. Notably, the reflection coefficient of the antenna is included in the derived equation. The accuracy of the proposed method is proven through simulation and measurements. It can be easily applied to a product examination by absorber manufacturers and customers owing to its advantages of simplicity, cost effectiveness, and non-cutting examination.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2727-2731
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• 2011

A new method for the determination of josamycin has been developed based on quenching of the fluorescence of 3-mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) by josamycin in ethanol. Reaction time, interfering substances on the fluorescence quenching, and mechanism of the interaction of CdTe QDs with josamycin were investigated. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of josamycin between 12.0 and 120.0 ${\mu}g\;mL^{-1}$ with a correlation coefficient of 0.9956 and a detection limit of 2.5 ${\mu}g\;mL^{-1}$. The proposed method was successfully applied to commercial tablets, and the results were satisfactory, i.e. consistent with those of high-performance liquid chromatography (HPLC).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.101-103
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• 2011

Various desired performances of concrete cannot be always obtained by current conventional mix proportion methods for recycled aggregate concrete (RAC). This paper suggests a new design method of mix proportion for RAC to reduce the number of trial mixes using genetic algorithm (GA) which has been an optimization technique to solve the multi-object problem. In mix design method by GA, several fitness functions for the required properties of concrete, i.e., slump, strength, price, and carbonation speed coefficient were considered based on conventional data or fitness function. As a result, various optimum mix proportions for RAC that meet required performances were obtained and the risk evaluation was also conducted for selected mixtures.

• Journal of International Society for Simulation Surgery
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• v.3 no.2
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• pp.46-48
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• 2016

Purpose In face reocognition area, estimating occlusion in face images is on the rise. In this paper, we propose a new face recognition algorithm based on dual sparse representation to solve this problem. Method Each face image is partitioned into several pieces and sparse representation is implemented in each part. Then, some parts that have large sparse concentration index are combined and sparse representation is performed one more time. Each test sample is classified by using the final sparse coefficient where correlation between the test sample and training sample is applied. Results The recognition rate of the proposed algorithm is higher than that of the basic sparse representation classification. Conclusion The proposed method can be applied in real life which needs to identify someone exactly whether the person disguises his face or not.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.779-783
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• 1996

Cation exchange distribution coefficients of poly(dithiocarbamate) were presented for $Cd^{2+}$, $Cr^{3+}$, and $Pb^{2+}$ in HCI. The distribution coefficients were determined tv using the batch method. Based on these distribution data, the separation possibilities of the heavy metal ions were discussed. The distribution coefficients of three heavy metal ions on dithiocarbamate resin were decreased as HCI concentrations were increased. The selective separation of $Cr^{3+}$ and $Cd^{2+}$ was possible by using 0.1M HCl in dithiocarbamate resin and the reproducibility test showed that the average absorptivity of resin was 90% in the case of $Cd^{2+}$ ion by the column method.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.59-64
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• 2010

A design method of Sirocco fan is developed for constructing 3-D impeller and scroll geometries, and for predicting both the aerodynamic performance and the noise characteristics of the designed fan. The aerodynamic blading design of fan is conducted by blade angle, camber line determinations and airfoil thickness distribution, and then the scroll geometry of fan is designed by using logarithmic spiral. The aerodynamic performance of designed fan is predicted by the meanline analysis with flow blockage, slip and pressure loss correlations. Based on the predicted performance data, fan noise is predicted by two models for cutoff frequency and broadband noise sources. The present predictions for the performance and the noise level of actual fans are well agreed with measurement results.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1208-1211
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• 2002

The robust controller for the nuclear reactor power control system is designed. The reactor model is described in the form of transfer function and the bound of each coefficient is determined to set up the linear interval system. By the Kharitonov and the edge theorem, a frequency based design template is made and applied to the determination of the controller. The controller designed by this method is simpler than that obtained by the H(equation omitted). Although the controller is designed with the basis of high power, it could be used even at low power.

• Journal of Korea Foundry Society
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• v.16 no.6
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• pp.550-555
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• 1996

A stochastic model, based on the coupling of the finite volume(FV) method for macroscopic heat flow calculation and a two-dimensional cellular automaton(CA) model for treating microstructural evolution was applied-for the prediction of microstructural evolution in squeeze casting. The interfacial heat transfer coefficient at the casting/die interface was evaluated as a function of time using an inverse problem method in order to provide a quantitative simulation of solidification sequences under high pressure. The effects of casting process variables on the formation of solidification grain structures and on the columnar to equiaxed transition of an Al-4.5wt%Cu alloy in squeeze casting were investigated. The calculated solidification grain structures were in good agreement with those obtained experimentally.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.10
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• pp.130-139
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• 1994

Video compression algorithms are based on removing spatial and/or temproal redundancy inherent in image sequences by predictive(DPCM) encoding, transform encoding, or a combination of predictive and transform encoding. In this paper, each 8$\times$8 DCT coefficient of DFD(displaced frame difference) is adaptively quantized by one of the four quantizers depending on total distortion level, which is determined by characteristics of HVS(human visual system) and buffer status. Therefore, the number of possible quantizer selection vectors(patterns) is 4$^{64}$. If this vectors are coded, toomany bits are required. Thus, the quantizer selection vectors are limited to 2048 for Y and 512 for each U, V by the proposed method using SWAD(sum of weighted absolute difference) for discriminating vectors. The computer simulation results, using the codebook vectors which are made by the proposed method, show that the subjective and objective image quality (PSNR) are goor with the limited bit allocation. (17Mbps)

• Journal of Ship and Ocean Technology
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• v.4 no.1
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• pp.28-36
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• 2000

Numerical simulation based on the superposition of ring waves generated by the linear periodic source distributions for the plunger type wave maker was accomplished. The characteristics of directional spreading function were investigated. Mirror images are also introduced to consider reflections of side-wall together with the reflection coefficient to account for the imperfect reflection from the real side wall in the long experimental towing tank. Unexpected spurious waves, resulting from the combined effect of finite breadth of segmented wave maker, wavelength and main wave maker, wavelength and main wave propagating direction, were observed in the line source method and also in the analysis of the directivity. The influence of spurious waves to the directional spreading function was also investigated.