• Analytical Science and Technology
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• v.17 no.6
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• pp.481-488
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• 2004

Solvent extraction of Ni(II) into a chloroform by using salen[N,N'-Bis (salicylidene)-ethylenediamine] as a ligand has been studied. Salen was synthesized from ethylenediamine and salicylaldehyde by simple condensation reaction in an ethanol. Salen formed a 1 : 1 complex with Ni(II) and its extraction constant was $10^{5.12}$. For the determination of Ni(II) in sea water samples, some experimental conditions such as pH of solution, amount of salen, acid type and concentration for back extraction, extraction time, and influence of foreign ions were optimized by using a synthetic sea water. The sea water of which the composition was similar to a natural sea water was synthesized in this laboratory. Trace Ni(II) was extracted into the chloroform in the weak basic solution above pH 8. And the nickel could be quantitatively extracted with the concentration of salen higher than $1.2{\times}10^{-4}mol/L$. This concentration was more than 180 times of Ni(II) in the solution with a mole ratio. Real samples of Korean coastal sea water were analyzed under optimized conditions. Even though Ni(II) was not detected in these samples. Recoveries more than 98% were obtained in the samples which 40 ng/mL of Ni(II) was spiked. And detection limit of proposed method was 1.3 ng/mL. From these results, it could be known that salen of this type would be applied for the determination of trace metals as an organic chelating reagent.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.35-41
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• 2020

Fast Fourier transform (FFT) processors have been widely used in various application such as communications, image, and biomedical signal processing. Especially, high-performance and low-power FFT processing is indispensable in OFDM-based communication systems. This paper presents a novel radix-26 FFT algorithm with low computational complexity and high hardware efficiency. Applying a 7-dimensional index mapping, the twiddle factor is decomposed and then radix-26 FFT algorithm is derived. The proposed algorithm has a simple twiddle factor sequence and a small number of complex multiplications, which can reduce the memory size for storing the twiddle factor. When the coefficient of twiddle factor is small, complex constant multipliers can be used efficiently instead of complex multipliers. Complex constant multipliers can be designed more efficiently using canonic signed digit (CSD) and common subexpression elimination (CSE) algorithm. An efficient complex constant multiplier design method for the twiddle factor multiplication used in the proposed radix-26 algorithm is proposed applying CSD and CSE algorithm. To evaluate performance of the previous and the proposed methods, 256-point single-path delay feedback (SDF) FFT is designed and synthesized into FPGA. The proposed algorithm uses about 10% less hardware than the previous algorithm.

• Korean Journal of Remote Sensing
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• v.33 no.3
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• pp.257-266
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• 2017

In this study, the dust/smoke detection algorithm was developed with a multi-spectral satellite remote sensing method using Moderate resolution Imaging Spectroradiometer (MODIS) Level 1B (L1B) data and the results were validated as RGB composite images of red(R; band 1), green(G; band 4), blue(B; band 3) channels using MODIS L1B data and Cloud-Aerosol Lidar with Orthogonal Polarization Satellite Observations(CALIPSO) Vertical Feature Mask (VFM) product. In the daytime on March 30, 2007 and April 27, 2012, the consistencies between the dust/smoke detected by this algorithm and verification data were approximately 56.4 %, 72.0 %, respectively. During the nighttime, the similar consistency was 40.5 % on April 27, 2012. Although these results were analyzed for limited cases due to the spatiotemporal matching for the MODIS and CALIPSO satellites, they could be used to utilize the aerosol detection of geostationary satellites for the next generations in Korea through further research.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.163-170
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• 1998

The ultimate goal of total artificial heart is permanent substitute for a failed heart in a patient without any other therapeutic modality. Until now, infection has been the main problem related to the mechanical circulatory support system. The best way to solve this catastrophic complication and to improve the quality of life of TAH patients in terms of tethering must be implantation of TAH totally. The EH-TAH has been developed in NCVC from 1987 for this purpose. The system consists of an energy converter and pumps, which are designed to be placed in abdomen and pericardial space separately for a good anatomical fit. To evaluate the anatomical fit and hemodynamic performance of the EH-TAH, in vivo test was done. General condition of the animal and hemodynamic status had been stable until the TAH stopped on the 11th pumping day. The estimated cardiac output was about 7.7L/min. The values of mean aortic pressure, left and right atrial pressure were 93$\pm$10, 19$\pm$3 and 15$\pm$4 mmHg, respectively. The correlation coefficient between left and right atrial pressure was 0.96, which represents the dynamic function of the interatrial shunt in controlling left-right imbalance of cardiac output. During pumping days, the temperature on the surface of actuator had been maintained at 39.7$\pm$0.4$^{\circ}C$, less than 1$^{\circ}C$ higher than the rectal temperature. The TAH stopped on the 11th day due to mechanical problems. We concluded that the EH-TAH possessed satisfactory basic performance including anatomic fit and hemodynamic adequacy, although there were several mechanical problems to be solved yet.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4038-4045
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• 2011

To investigate whitening Effects of Angelica dahurica Radix Ethanol Extract (ADEE), we used melan-a cell line, brown guinea pig, and HMB-45. We treated with ADEE of 6.25, 12.5, 25, and 50 ${\mu}g/m{\ell}$ concentration in order to evaluate the effect of ADEE on cell viability and on morphological observation of melan-a cells. Also we were induced the artificial tanning spots by 1,500 mJ/$cm^2$ of ultraviolet B radiation on the backs of brown guinea pigs (approximately 450~500g) and then the test agent of $30{\mu}{\ell}$ was applied on the spots twice a day, five days a week, for five weeks respectively. The visible whitening effect was evaluated once a week. At the end of the experiment, the animals were sacrificed under anesthetization. The artificial tanning spots were obtained by biopsy punch and stained with HMB-45 to observe the gp100 proteins which were melanosomes. Our results show that cell viability was not reduce at ADEE concentrations between 6.25 and 50 ${\mu}g/m{\ell}$, melanin synthesis and melanocyte dendricity were decreased in ADEE treated melan-a cells increasing ADEE concentration. In the gross observation, ADEE treated groups had lower pigmentation than the vehicle control groups. And in the histological observation, ADEE treated groups had lower melanocytes than the vehicle control groups. Also in the quantitative analysis of the gp100 proteins using image analysis software, ADEE treated groups had a significantly lower value (p<0.001) than the vehicle control group and this resultsagreed with the results of observation under microscope. From these results, weconcluded that ADEE had positive whitening effect.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.265-272
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• 2007

This proposed gamma (${\gamma}$) correction system is developed to reduce the difference between non-linear gamma curve produced by a typical formula and result produced by the proposed algorithm. In order to reduce the difference, the proposed system is using the Least Squares Polynomial which is calculating the best fitting polynomial through a set of points which is sampled. Each system is consisting of continuous several kinds of equations and having their own overlap sections to get more precise. Based on the algorithm verified by MATLAB, the proposed systems are implemented by using Verilog-HDL. This paper will compare the previous algorithm of gamma system such as Existing system with Seed Table with the latest that such as Proposed system. The former and the latter system have 1, 2 clock latency; each 1 result per clock. Because each of the error range (LSB) is $1{\sim}+1,\;0{\sim}+36$, we can how that Proposed system is improved. Under the condition of SAMSUNG STD90 0.35 worst case, each gate count is 2,063, 2,564 gates and each maximum data arrival time is 29.05[ns], 17.52[ns], respectively.

• Korean Journal of Remote Sensing
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• v.35 no.5_1
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• pp.681-692
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• 2019

In this paper, a hybrid deep learning model, called 2D convolution with bidirectional long short-term memory (2DCBLSTM), is presented that can effectively combine both spatial and temporal features for crop classification. In the proposed model, 2D convolution operators are first applied to extract spatial features of crops and the extracted spatial features are then used as inputs for a bidirectional LSTM model that can effectively process temporal features. To evaluate the classification performance of the proposed model, a case study of crop classification was carried out using multi-temporal unmanned aerial vehicle images acquired in Anbandegi, Korea. For comparison purposes, we applied conventional deep learning models including two-dimensional convolutional neural network (CNN) using spatial features, LSTM using temporal features, and three-dimensional CNN using spatio-temporal features. Through the impact analysis of hyper-parameters on the classification performance, the use of both spatial and temporal features greatly reduced misclassification patterns of crops and the proposed hybrid model showed the best classification accuracy, compared to the conventional deep learning models that considered either spatial features or temporal features. Therefore, it is expected that the proposed model can be effectively applied to crop classification owing to its ability to consider spatio-temporal features of crops.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1555-1565
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• 2018

Detection of subtle ground deformation of volcanoes plays an important role in evaluating the risk and possibility of volcanic eruptions. Ground-fixed observation equipment is difficult to maintain and cost-inefficient. In contrast, satellite remote sensing can regularly monitor at low cost. In this paper, following the study of Chadwick et al. (2006), which applied the interferometric SAR (InSAR) technique to the Sierra Negra volcano, Galapagos. In order to investigate the deformation of the volcano before 2005 eruption, the recent activities of this volcano were analyzed using Sentinel-1, the latest SAR satellite. We obtained the descending mode Sentinel-1A SAR data from January 2017 to January 2018, applied the Persistent Scatter InSAR, and estimated the depth and expansion quantity of magma in recent years through the Mogi model. As a result, it was confirmed that the activity pattern of volcano prior to the eruption in June 2018 was similar to the pattern before the eruption in 2005 and was successful in estimating the depth and expansion amount. The results of this study suggest that satellite SAR can characterize the activity patterns of volcano and can be possibly used for early monitoring of volcanic eruption.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1407-1419
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• 2020

Long time-series gridded data is crucial for the analyses of Earth environmental changes. Climate reanalysis and satellite images are now used as global-scale periodical and quantitative information for the atmosphere and land surface. This paper examines the feasibility of DCT-PLS (penalized least square regression based on discrete cosine transform) for the spatial gap filling of gridded data through the experiments for multiple variables. Because gap-free data is required for an objective comparison of original with gap-filled data, we used LDAPS (Local Data Assimilation and Prediction System) daily data and MODIS (Moderate Resolution Imaging Spectroradiometer) monthly products. In the experiments for relative humidity, wind speed, LST (land surface temperature), and NDVI (normalized difference vegetation index), we made sure that randomly generated gaps were retrieved very similar to the original data. The correlation coefficients were over 0.95 for the four variables. Because the DCT-PLS method does not require ancillary data and can refer to both spatial and temporal information with a fast computation, it can be applied to operative systems for satellite data processing.

• Journal of Broadcast Engineering
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• v.27 no.2
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• pp.216-227
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• 2022

The MPEG-I (Immersive) group is working on a standardization project for immersive video that provides 6 degrees of freedom (6DoF). The MPEG Immersion Video (MIV) standard technology is intended to provide limited 6DoF based on depth map-based image rendering (DIBR) technique. Many efficient coding methods have been suggested for MIV, but efficient transmission strategies have received little attention in MPEG-I. This paper proposes group-based adaptive rendering method for immersive video streaming. Each group can be transmitted independently using group-based encoding, enabling adaptive transmission depending on the user's viewport. In the rendering process, the proposed method derives weights of group for view synthesis and allocate high quality bitstream according to a given viewport. The proposed method is implemented through the Test Model for Immersive Video (TMIV) test model. The proposed method demonstrates 17.0% Bjontegaard-delta rate (BD-rate) savings on the peak signalto-noise ratio (PSNR) and 14.6% on the Immersive Video PSNR(IV-PSNR) in terms of various end-to-end evaluation metrics in the experiment.