• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.12A
• /
• pp.2027-2035
• /
• 2001

In this paper, we present an audio stream delivery using the AMR (Adaptive Multi-Rate) coder that was adopted by ETSI and 3GPP as a standard vocoder for next generation IMT-2000 service in which includes combined sender (FEC) and receiver reconstruction technique in the Internet. By use of the media-specific FEC scheme, the possibility to recover lost packets can be much increased due to the addition of repair data to a main data stream, by which the contents of lost packets can be recovered. The AMR codec is based on the code-excited linear predictive (CELP) coding model. So we use a frame erasure concealment for CELP-based coders. The proposed scheme is evaluated with ITU-T G.729 (CS-ACELP) coder and AMR - 12.2 kbit/s through the SNR (Signal to Noise Ratio) and the MOS (Mean Opinion Score) test. The proposed scheme provides 1.1 higher in Mean Opinion Score value and 5.61 dB higher than AMR - 12.2 kbit/s in terms of SNR in 10% packet loss, and maintains the communicab1e quality speech at frame erasure rates lop to 20%.

• Journal of Radiation Protection and Research
• /
• v.22 no.4
• /
• pp.299-307
• /
• 1997

The individual dose equivalent, $H_p$, effective dose, E, and gender specific effective dose, $E^m$ and E$^f$, were evaluated using the male and female phantoms of MIRD type located in the radial gamma radiation field near a point source. The point sources were placed at the distances of 15, 40 and 100 cm in front of the body at different heights. Two radionuclides, $^{137}Cs$ and $^{131}I$, were selected for the illustrative examples. In terms of the gender specific effective doses, $E^f$ is higher than $E^m$ with a few exceptions, e.g. the case where the point source is at the height of reproductive organs, but the differences from the sex- averaged values are not significant enough to justify use of gender specific dose conversion factors for the radial gamma field. The ratios $H_p$/E were in the range of 1 to 3 depending on the source and dosimeter positions when the dosimeter is worn on the front surface of the torso covering from chest to lower abdomen, but varied from 0.34 to 6.5 in extreme cases. When it is assumed that the typical handling procedure of radioactive source material and the typical dosimeter position(on the chest) be respected, the dosimeters calibrated against the broad parallel field appear to provide estimates with acceptable errors for the effective dose of workers exposed to radial broad gamma field around a point source.

• Journal of radiological science and technology
• /
• v.45 no.6
• /
• pp.523-529
• /
• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• Journal of the Korean Wood Science and Technology
• /
• v.52 no.5
• /
• pp.423-437
• /
• 2024

Wood biomass, such as sawdust, particles, and chips from the wood industry, can be potentially used as a composite product. Chip block pallets (CBP) are composite products that can be produced from industrial wood waste and are in high demand in the logistics sector. Therefore, this study aimed to investigate the production of CBP from teak wood biomass with varying polyurethane contents. In addition, this study analyzed the optimum particle-size composition was determined. The CBP production of CBP be divided into two stages. The first stage evaluated the use of polyurethane adhesive content, whereas the second stage considered the effect of particle size composition. The 9 × 9 × 9 cm³ of CBP with 0.6 g/cm³ target density was fabricated using a cold press. The National Wooden Pallet and Container Association (NWPCA) standards were used to evaluate the density, moisture content, dimensional stability, water absorption, compressive strength (CS), and screw-holding strength (SHS) of our CBP products. The mechanical and physical properties of CBP products were investigated. As a result, the CBP sample prepared using 4-14 mesh particle size and 4.5% adhesive content showed the optimal strength values, such as CS of 14.67 MPa and SHS of 371.50 N. These findings demonstrate that the CBPs derived from teak wood waste closely resemble commercial chip blocks and have the potential to replace wood bearings as pallet pads.

• Journal of Convergence for Information Technology
• /
• v.10 no.6
• /
• pp.119-127
• /
• 2020

The purpose of this study is to verify the effect on the creativity and Usability of young Children by applying design education pro young Children gramfor using 3D printer to the kindergarten field and, through the results, to prepare a realistic way to increase the utilization of 3D printer media in infant classrooms. In order to achieve this research purpose, 38 infants aged 5 from G kindergarten located in metropolitan A are divided into each experimental group and comparative group, and from August 2017 to January 2018, data were collected through 15 experiments over a period of about 6 months. As a research tool, in the Korean version of Torrance's Creativity Test, an infant shape test and a usability test scale were used, and the data processing and analysis were conducted through technical statistical methods and covariance analysis. As a result of the study, the program using 3D printer had a statistically significant effect on promoting creativity and Usability of young Children, and in particular, it had a remarkable effect on the elaboration of creativity composition. Based on these results, discussions on the existing Nuri process, which mainly aims to cultivate creative talents, the possibility of connecting 3D printers more widely and the role of teachers were made.

• Korean Journal of Materials Research
• /
• v.23 no.6
• /
• pp.309-315
• /
• 2013

$GdBa_2Cu_3O_{7-y}$(Gd123) powders were synthesized by the solid-state reaction method using $Gd_2O_3$ (99.9% purity), $BaCO_3$ (99.75%) and CuO (99.9%) powders. The synthesized Gd123 powder and the Gd123 powder with $Gd_2O_3$ addition ($Gd_{1.5}Ba_2Cu_3O_{7-y}$(Gd1.5)) were used as raw powders for the fabrication of Gd123 bulk superconductors. The Gd123 and Gd1.5 bulk superconductors were fabricated by sintering or a top-seeded melt growth (TSMG) process. The superconducting transition temperature ($T_{c,onset}$) of the sintered Gd123 was 93 K and the transition width was as large as 20 K. The $T_{c,onset}$ of the TSMG processed Gd123 was 82 K and the transition width was also as large as 12 K. The critical current density ($J_c$) at 77 K and 0 T of the sintered Gd123 and TSMG processed Gd123 were as low as a few hundreds A/$cm^2$. The addition of 0.25 mole $Gd_2O_3$ and 1 wt.% $CeO_2$ to Gd123 enhanced the $T_c$, $J_c$ and magnetic flux density (H) of the TSMG processed Gd123 sample owing to the formation of the superconducting phase with high flux pinning capability. The $T_c$ of the TSMG processed Gd1.5 was 92 K and the transition width was 1 K. The $J_cs$ at 77 K (0 T and 2 T) were $3.2{\times}10^4\;A/cm^2$ and $2.5{\times}10^4\;A/cm^2$, respectively. The H at 77 K of the TSMG-processed Gd1.5 was 1.96 kG, which is 54% of the applied magnetic field (3.45 kG).

• Journal of Convergence for Information Technology
• /
• v.9 no.6
• /
• pp.1-6
• /
• 2019

In this study, the development of a weight estimation model of electronic scale with nonlinear characteristics is presented using polynomial regression analysis. The output voltage of the load cell was measured directly using the reference mass. And a polynomial regression model was obtained using the matrix and curve fitting function of MS Office Excel. The weight was measured in 100g units using a load cell electronic scale measuring up to 5kg and the polynomial regression model was obtained. The error was calculated for simple($1^{st}$), $2^{nd}$ and $3^{rd}$ order polynomial regression. To analyze the suitability of the regression function for each model, the coefficient of determination was presented to indicate the correlation between the estimated mass and the measured data. Using the third order polynomial model proposed here, a very accurate model was obtained with a standard deviation of 10g and the determinant coefficient of 1.0. Based on the theory of multi regression model presented here, it can be used in various statistical researches such as weather forecast, new drug development and economic indicators analysis using logistic regression analysis, which has been widely used in artificial intelligence fields.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.66 no.1
• /
• pp.37-71
• /
• 2021

Rapeseed is a typical winter crop, and its freezing stress tolerance is a major feature for winter survival. Therefore, it is important to comprehend clearly the physical and molecular mechanisms of rapeseed under freezing stress conditions. This study investigates the physical and transcriptome changes of two rapeseed lines, 'J8634-B-30' and 'EMS26', under cold acclimation and freezing temperature treatments. The proline content of 'J8634-B-30' at 5 ℃ increased 8.7-fold compared to that before treatment, and there was no significant change in that of 'EMS26' RNA-sequencing analysis revealed 5,083 differentially expressed genes (DEGs) of 'J8634-B-30' under cold acclimation condition. Among the genes, 2,784 (54.8%) were up-regulated and 2,299 (45.2%) were down-regulated. The DEGs of 'EMS26' under cold acclimation condition were 5,831 genes, and contained 2,199 up-regulated genes (37.7%) and 3,632 down-regulated genes (62.3%). Among them, only DEGs annotated in the cold response-related signaling pathways were selected, and their expression in the two rapeseed lines was compared. Comparative DEGs analysis indicated that cold response related signaling pathways are proline metabolism and ABA (Abscisic acid) signaling. And ICE (Inducer of CBF expression) - CBF (C-repeat-binding factor) - COR (Cold-regulated) signaling were the significantly differentially expressed transcripts in the two rapeseed lines. The major induced transcripts of 'J8634-B-30' induced P5CS (Δ'-pyrroline-5-carboxylate synthetase), which is related to proline biosynthesis, PYL (pyrabactin resistance-like protein, ABA receptor) and COR413 (cold-regulated 413 plasma membrane 1). In conclusion, these result provide a foundation for understanding the mechanisms of freezing stress tolerance in rapeseeds. Further functional studies should be performed on the freezing stress-related genes identified in this study, which can contribute to the transgenic and molecular breeding for freezing stress tolerance in rapeseed.

• Journal of the Korean Dietetic Association
• /
• v.5 no.1
• /
• pp.64-73
• /
• 1999

Carbohydrate(CHO) counting is a meal planning approach used with diabetic patients that focuses on carbohydrate as the primary nutrient affecting post-prandial glycemic response. However, it has not been used in meal management of diabetic patients in Korea. CHO counting can be used by clients with type 1 and 2 diabetes. The purpose of the study was to determine the barriers to utilize the CHO counting when three levels of CHO counting were educated to type 2 diabetic patients who started continuous subcutaneous insulin infusion (CSⅡ) therapy by nutrition lectures and counseling. And the CHO-to-insulin ratios were determined for the individual patients who followed the carbohydrate counting as a meal management, and the factors to influence the CHO-to-insulin ratios were selected through the stepwise regression analysis. Twenty- four subjects were received three lectures, and one or two nutritional counseling for a month. The average age of the subjects was 50.7 years, and the duration of diabetes was 9.4 years. Their body mass index (BMI) was 21.5 kg/$m^2$. The difficulties of using CHO counting were 1) confusing the CHO exchange system to diabetic food exchange system, 2) lack of basic nutrition and not distinguishing nutrients such as CHO, fat and calorie, and 3) lack of motivation to make effort to count and record the amount of carbohydrates eaten. Nutritional counseling replenished the nutrition education and made patients practice CHO counting. Average CHO-to-insulin ratios at breakfast, lunch and dinner were 4.1$\pm$3.3, 2.9$\pm$2.6 and 2.9$\pm$3.0units/23g of CHO, respectively. CHO-to-insulin ratios were influenced by gender, age, BMI, post-prandial blood glucose levels and post-prandial c-peptide levels. The effective education and nutritional counseling of CHO counting can make CHO counting applicable to type 2 diabetic patients as meal management for improving glycemic control with less hypoglycemic episode.

• Journal of Convergence for Information Technology
• /
• v.10 no.10
• /
• pp.100-108
• /
• 2020

The purpose of this study is to identify the differences in self-efficacy, clinical performance ability, and critical thinking disposition after applying education integrated educational virtual reality simulation to training and outside school clinical practice to nursing college students and to provide them as basic data for effective practical education. This study was conducted from June 8 to July 3, 2020, and enrolled in the 3rd year of university in G city, and 30 subjects who did not receive virtual reality simulation training or outside school clinical training at all. Data were analyzed by Paired t-test. As a result of the study, the result of pretest and posttest to each group showed statistically significant improvements in self-efficacy, clinical performance ability, and critical thinking disposition. As a results of the study, education integrating virtual reality simulation training and clinical practice for nursing students to improves clinical performance ability, improves critical thinking, and self-efficacy, so it is thought that various virtual reality simulation training must be suitable for clinical situations before practice is necessary.