• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.463-470
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• 2016

In this paper, the characteristics analysis of LMD track, such as including track structure, track wear resistance and track thickness, were analyzed to enhance the deposition efficiency using a diode-pumped disk laser. SKD61 hot work steel plate and Fe based AISI M2 alloy were used as a the substrate and powder for the LMD process, respectively. The laser power, track pitch and powder feed rate among LMD parameters were adopted to estimate the deposition efficiency. As the laser power is increased, heat input and melting pool on the substrate is grown also increases, so resulting in the increased LMD track thickness was increased. Through EPMA mapping analysis of the cross-section in the LMD track, it was observed that all the elements are evenly distributed inside. Therefore, the entire hardness in the LMD track is expected to be almost uniform regardless of location. The characteristics of the LMD specimen were excellent compared to the STD11 specimen in terms of the wear track width and the wear rate as well as the coefficient of friction. Especially the wear rate of LMD specimen has been significantly reduced by 60 % or more. From Based on the experimental results, the prediction formula of LMD thickness was calculated by using laser power, track pitch and powder feed rate.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.3
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• pp.127-132
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• 2011

The silicon-containing Diamond-like Carbon (Si-DLC) film as an low friction coefficient coating has especially treated a different silicon content by plasma-enhanced chemical vapor deposition (PECVD) process at $500^{\circ}C$ on nitrided-STD 11 mold steel with (TMS) gas flow rate. The effects of variable silicon content on the Si-DLC films were tested with relative humidity of 5, 30 and 85% using a ball-on-disk tribometer. The wear-tested and original surface of Si-DLC films were analysed for an understanding of physical and chemical characterization, including a changing structure, via Raman spectra and nano hardness test. The results of Raman spectra have inferred a changing intra-structure from dangling bonds. And high silicon containing DLC films have shown increasing carbon peak ratio ($I_D/I_G$) values and G-peak values. In particular, the tribological tested surface of Si-DLC was shown the increasing hardness value in proportional to TMS gas flow rate. Therefore, at same time, the structure of the Si-DLC film was changed to a different intra-structure and increased hardness film with mechanical shear force and chemical reaction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1541-1550
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• 2004

In this paper, we propose an advanced hardware architecture for fast multi-resolution motion estimation of the video coding standard MPEG-1,2 and MPEG-4 AVC. We describe the algorithm and derive hardware architecture emphasizing the importance of area for low cost and fast operation by using the shared memory, the special ram architecture, the motion vector for 4 pixel x 4 pixel, the spiral search and so on. The proposed architecture has been verified by ARM-interfaced emulation board using Excalibur Altera FPGA and also by ASIC synthesis using Samsung 0.18 m CMOS cell library. The ASIC synthesis result shows that the proposed hardware can operate at 140 MHz, processing more than 1,100 QCIF video frames or 70 4CIF video frames per second. The hardware is going to be used as a core module when implementing a complete MPEG-4 AVC video encoder ASIC for real-time multimedia application.

• 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.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.11-18
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• 2015

Stress is one of the major causes threatening the mental and physical health of human today. In this paper, we analyzed the heart rate variability(HRV), galvanic skin response(GSR), and skin temperature data measured from the university subjects before and after the class to examine the influence on bio-signal in stress environment. Thirty subjects from university students (aged between 21 and 27 years; mean=22.31, STD=1.45) took part in this study. From the experiment results, RMSSD(p=0.033), LF peak(p=0.003), VLF(p=0.045) were statistically significant from those of the control group(p<0.05) of HRV both in time and frequency domain. We observed that mean skin conductivity after the class(mean=5.993(uS), SD=3.406) is higher than that before the class(mean=3.039(uS), SD=2.628) by 97.2% on average and the skin temperature after the class($34.835{\pm}0.305$) is slightly higher than that before the class($34.471{\pm}0.281$) by 1.055% on average. The results in this research could be used to examine the autonomic response in clinical stress related research.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1658-1664
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• 2014

Sprout vegetables containing various types of polyphenols and flavonoids, are known to have anti-inflammatory, antioxidant, cholesterol-lowering, and anti-obesity activities. However, there have been few reports on the anti-diabetic efficacy of sprout vegetables. Here, we investigated the anti-diabetic effects of sprout extract obtained from buckwheat, beet, rape, broccoli, kohlrabi, red young radish, and dachai, in high fat diet (HFD) and streptozotocin (STZ)-induced type II diabetes mellitus mice. The mice were fed a HFD (60% calories as fat) for 8 weeks prior to intraperitoneal injection with STZ (75 mg/kg). The diabetic mice were divided into four groups: standard diet (STD, 10% calories fat), HFD, HFD with sprout extract (SPE) and HFD with metformin (MET). After 4 weeks, body weight gain was much lower in both SPE and MET groups than in HFD group. In contrast, there was no difference experiment groups regarding food intake ratio. The level of fasting blood glucose was significantly lower in the SPE and MET groups compared to the HFD group. Oral glucose tolerance and insulin tolerance in the SPE and MET groups were significantly ameliorated in comparison to the HFD group. The concentrations of serum total cholesterol, triglycerides, and LDL cholesterol in the SPE and MET groups were remarkably reduced in comparison to the HFD group, and HDL cholesterol concentration was higher in the SPE and MET groups than in the HFD group. Glutamate oxaloacetate transaminase and glutamate pyruvate transaminase levels were between SPE and HFD groups. The serum insulin and leptin concentrations were significantly reduced in both the SPE and MET groups compared to the HFD group. Therefore, these results indicate that sprout extract could improve insulin resistance and attenuate blood glucose level in HFD/STZ-induced type II diabetes mellitus mice. We conclude that this study may provide positive insights into sprout extract as a functional food ingredient for treatment of type II diabetes mellitus.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.277-282
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• 2010

The study is to verify non-uniform dose distribution in Field-In-Field (FIF) technique using two-dimensional ionization chamber (MatriXX, Wellhofer Dosimetrie, Germany) for breast tangential irradiation. The MatriXX and an inverse planning system (Eclipse, ver 6.5, Varian, Palo Alto, USA) were used. Hybrid plans were made from the original twenty patients plans. To verify the non-uniform dose distribution in FIF technique, each portal prescribed doses (90 cGy) was delivered to the MatriXX. The measured doses on the MatriXX were compared to the planned doses. The quantitative analyses were done with a commercial analyzing tool (OmniPro IMRT, ver. 1.4, Wellhofer Dosimetrie, Germany). The delivered doses at the normalization points were different to average 1.6% between the calculated and the measured. In analysis of line profiles, there were some differences of 1.3-5.5% (Avg: 2.4%), 0.9-3.9% (Avg: 2.5%) in longitudinal and transverse planes respectively. For the gamma index (criteria: 3 mm, 3%) analyses, there were shown that 90.23-99.69% (avg: 95.11%, std: 2.81) for acceptable range ($\gamma$-index $\geq$ 1) through the twenty patients cases. In conclusion, through our study, we have confirmed the availability of the FIF technique by comparing the calculated with the measured using MatriXX. In the future, various clinical applications of the FIF techniques would be good trials for better treatment results.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1605-1613
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• 2023

The physical properties of the ocean interior are determined by temperature and salinity. To observe them, we rely on satellite observations for broad regions of oceans. However, the satellite for salinity measurement, Soil Moisture Active Passive (SMAP), has low temporal and spatial resolutions; thus, more is needed to resolve the fast-changing coastal environment. To overcome these limitations, the algorithm to use the Geostationary Ocean Color Imager-II (GOCI-II) of the Geo-Kompsat-2B (GK-2B) was developed as the inputs for a Multi-layer Perceptron Neural Network (MPNN). The result shows that coefficient of determination (R²), root mean square error (RMSE), and relative root mean square error (RRMSE) between GOCI-II based sea surface salinity (SSS) (GOCI-II SSS) and SMAP was 0.94, 0.58 psu, and 1.87%, respectively. Furthermore, the spatial variation of GOCI-II SSS was also very uniform, with over 0.8 of R² and less than 1 psu of RMSE. In addition, GOCI-II SSS was also compared with SSS of Ieodo Ocean Research Station (I-ORS), suggesting that the result was slightly low, which was further analyzed for the following reasons. We further illustrated the valuable information of high spatial and temporal variation of GOCI-II SSS to analyze SSS variation by the 11th typhoon, Hinnamnor, in 2022. We used the mean and standard deviation (STD) of one day of GOCI-II SSS, revealing the high spatial and temporal changes. Thus, this study will shed light on the research for monitoring the highly changing marine environment.