• KIPS Transactions on Software and Data Engineering
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• v.11 no.3
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• pp.133-140
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• 2022

We investigate the performance of deep learning-based Korean language models on a task of predicting the score range of Korean essays written by foreign students. We construct a data set containing a total of 304 essays, which include essays discussing the criteria for choosing a job ('job'), conditions of a happy life ('happ'), relationship between money and happiness ('econ'), and definition of success ('succ'). These essays were labeled according to four letter grades (A, B, C, and D), and a total of eleven essay score range prediction experiments were conducted (i.e., five for predicting the score range of 'job' essays, five for predicting the score range of 'happiness' essays, and one for predicting the score range of mixed topic essays). Three deep learning-based Korean language models, KoBERT, KcBERT, and KR-BERT, were fine-tuned using various training data. Moreover, two traditional probabilistic machine learning classifiers, naive Bayes and logistic regression, were also evaluated. Experiment results show that deep learning-based Korean language models performed better than the two traditional classifiers, with KR-BERT performing the best with 55.83% overall average prediction accuracy. A close second was KcBERT (55.77%) followed by KoBERT (54.91%). The performances of naive Bayes and logistic regression classifiers were 52.52% and 50.28% respectively. Due to the scarcity of training data and the imbalance in class distribution, the overall prediction performance was not high for all classifiers. Moreover, the classifiers' vocabulary did not explicitly capture the error features that were helpful in correctly grading the Korean essay. By overcoming these two limitations, we expect the score range prediction performance to improve.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.244-249
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• 2006

The residue depletion of amoxicillin was investigated in the olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major) after 7 days treatment with medicated feed at a dose of 400 mg/kg bw/day. Fishes were sampled for muscle on 1st, 2nd, 3rd, 4th, and 5th day after treatment. Amoxicillin concentrations were determined by high performance liquid chromatography with fluorescence detector. The recovery rates of amoxicillin in muscle samples ranged 84.3-101.3% and 75.0-91.5% for the concentration of 0.05 mg/kg and 0.1 mg/kg, respectively. Amoxicillin concentrations detected on 1st day after treatment were 0.137, 0.131, and 0.172 mg/kg in the muscle of olive flounder, rockfish, and red sea bream, respectively. After a withdrawal of 3 days, muscle concentrations were 0.012, 0.010, and 0.017 mg/kg in the olive flounder, rockfish, and red sea bream, respectively. Amoxicillin was not detectable in muscle samples on 4 days following withdrawal of the medicated feed. From results of the present study, a withdrawal period of amoxicillin is proposed on 4 days after 7 days treatment with medicated feed at a dose of 400 mg/kg bw/day to avoid the presence of excessive residues of the edible muscles of olive flounder, rockfish, and red sea bream.

• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.479-486
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• 2003

In this study, poly(DL-lactide-co-glycolide) nanoparticles loaded with water-insoluble vitamins such as vitamin A (Retinol) and vitamin E acetate were prepared by the emulsification diffusion method. Polymer solution was prepared by the two water-miscible organic solvent, such as ethanol and acetone. Because of its biocompatible property, polyethyleneglycol-polypropyleneglycol diblock copolymer was used as surfactant and stabilizer. The influence of some preparative variables on the nanoparticle formation and on the loading efficiency of active agents, such as the type and concentration of stabilizing agent, the stirring methods, the water/oil phase ratio and the polymer concentration were investigated in order to control and optimize the process. After preparation of nanoparticles loaded with active agent, particle size and distribution were evaluated by the light scattering particle analyzer. The loading efficiency of active agents was evaluated by the UV-visible spectroscopy. As the results, particle size were 50-200 nm and dispersibility was monodisperse. The optimum loading efficiency of active agents was observed 50-60%. It was found that the appropriate of selections of binary solvent mixtures and polymeric concentrations in both organic and aqueous phases could provide good yield and favorable physical properties of PLGA nanoparticles.

• Resources Recycling
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• v.7 no.5
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• pp.19-25
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• 1998

High temperature thermal behaviors of EAF dust by coke at initial reaction stage were studied to obtain the fundamental data of EAF dust treatment process, that is Extended Arc Plasma Furnace System called RAPID system. In this study thermal behaviors including calcination of limestone, devolatilization of EAF dust itself, and reduction & devolatilization of mixture(EAF dust : coke : limestone = 80 : 10 : 10 wt.%) were investigated as functions of reaction temperature (1000~1300$^{\circ}C$) and reaction time (3~12 min), considering the 180% equivalence of carbon reduction and 1.7 bacisity for optimum reduction and melting of EAF dust in the RAPID system. Size of sample was about below 0.1 mm for these experiments. Limestone was completely calcined at above 1100$^{\circ}C$ within 1 minutes. In the case of devolatilization of EAF dust itself, weight loss of EAF dust was about 14% at 1300$^{\circ}C$ and 12 minutes, and partial sintering and melting were found in part of sample. Weight loss of mixtures increased with increasing reaction temperature and time, about 46% weight loss in it was occurred at 1300$^{\circ}C$ and 12 minutes. From these weight losses showing devolatilization and reduction of EAF dust, the treatment time of EAF dust inside.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.250-256
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• 2002

Resistivity tomography has become an important tool to image underground resistivity distribution. This method has been widely applied to site investigation for engineering and environmental purpose. In resistivity tomography, various electrode arrays can be used and each array has both merits and demerits. For example, the pole-pole array has high signal to noise ratio (S/N ratio), but its resolution is too low. The dipole-dipole array has low S/N ratio, but its resolution is very high. The Pole-dipole may has intermediate Snf ratio and resolution. The modified Pole-dipole array, recently proposed, shows reasonable S/N ratio and resolution, which are comparable to the pole-dipole array. These electrode arrays except the pole-pole array, however, have the problem that the apparent resistivity can diverge at some special electrode Positions. Also, the Pole-Pole array may not reflect the doe resistivity of an anomalous body. In this study, we propose a new electrode array, mixed array, where pole-dipole and modified pole-dipole ways are selectively used with the relative positions of current and potential electrodes. The mixed array has the same level of S/N ratio and resolution as the pole-dipole array and the apparent resistivity does not diverge in the receiver hole. Furthermore, the apparent resistivity using the array can reflect the true resistivity of the anomalous body.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.8-14
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• 2000

Long term cultivation crops like tomato, capsicum, melon etc. demand much amount of continuous supplying of nutrition during the whole growing periods. It is not easy to cover satisfactorily the nutritional demands for them by splitted top dressings, slow release fertilizer applications and fertigation systems. To overcome these problems, the "CULTAN" (Controlled Uptake Long Term Ammonium Nutrition) Beaker Deposit techniques have been developed and it was put into PVC beaker with the combined nitrogen fertilizer type mixed with the ratio of one-third of ammonium sulfate-N and two-thirds of urea-N, in which nitrogen was loaded on the demanding amount of a tomato plant during the growing period. Gypsum was mixed as a binder, and loamy soil and compost were used as a diffusion regulator. It was placed upside down into root zone of tomato at the transplanting. Tomato roots were spreaded into the Deposit beaker by ammonium ions which attract root growth. The tomato fruit yield and nitrogen uptake by plant were increased by application of $NH_4$-Beaker deposit fertilizer rather than those of common fertilizer treatment. In conclusion, it was able to improve economic and ecological benefits through CULTAN system compared with common fertilization systems. CULTAN system was estimated as a prospective alternative to enhance productivity and minimize nutrient lose. In addition, it shows further developing possibility of CULTAN system by the supplement of micro-nutrients and pesticides in the macro-nutrient beaker deposits.

• Analytical Science and Technology
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• v.19 no.3
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• pp.263-271
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• 2006

The levels of total PCBs, Co-PCBs and PCDD/Fs in the transformer insulation oil samples obtained using GC/ECD and HRGC/HRMS were ranged from N.D. to 77.3 ppm, from 0.0863 to 2.49 ppm and from N.D. to 0.00241 ppm, respectively. In terms of WHO-TEQ values, Co-PCBs and PCDD/Fs were ranged from 23.3 to 600 pgTEQ/g and from N.D. to 128 pgTEQ/g, respectively (${\Sigma}Co$-PCBs+PCDD/Fs concentration was calculated 24.4~728 pgTEQ/g). Although, the contribution of PCDD/Fs was below 12% in total TEQ concentration, it is suggested contamination of PCDD/Fs in transformer insulation oils. Among 10 samples, 4 samples showed higher concentration than 2 ppm (specific waste criterion of Korea) and Aroclor 1242, 1248, 1254 and 1260 was detected in samples as a single or mixture of Aroclor. It was shown reliable relationship between concentration of Co-PCBs and those of PCDD/Fs (p<0.003), however, was not shown between production year of transformer and concentration of PCBs. The distribution pattern of Co-PCB congeners showed that the ratios of mono-ortho substituted congeners were higher than non-ortho substituted congeners. Among that, PCB-118 congener was predominant. In addition, the OCDD congener was predominated in PCDD/Fs congeners as above 53%. Moreover, the congener pattern of Co-PCBs was similar to that of Aroclor as well as ambient air, which suggested that PCBs volatilization from transformer insulation oil affected the pattern of Co-PCBs in ambient air.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.383-387
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• 2014

In this paper, for a new detection system development with the better accurate dose evaluation and beam distribution imaging using the small field irradiation of linear accelerator, the compound semiconductor based detection sensors were fabricated and the performance evaluation was investigated. The special particle-in-binder sedimentation was used for a large area film sensor fabrication. The detection properties for high energy x-rays were investigated from a dark current, an output current, a rising time, a falling time, and response delay measurement. The experimental results, the $TiO_2$ mixed $HgI_2$ sensor showed the best electrical characteristics than $PbI_2$, PbO, pure $HgI_2$. Linearity, repeatability, and accuracy tests from LINAC were tested, the $TiO_2$ mixed $HgI_2$ sensor showed the better performance than the commercially available dosimetry devices.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.236-244
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• 2006

Water quality fluctuation of Gyeongan water area in Paldang reservoir, which measured from the downstream sampling point of Gyeongan stream (G1) to dam sampling point (P), was examined in the light of seasonal rainfall and regional difference in the year of 2002. Annual COD, T-P and T-N concentration dropped conspicuously at the point P (in front of dam) although concentration of Gl point was high. Concentration variation of COD, T-P and T-N from Gl to P point in Gyeongan area was small in August and September. And at G l point showed relatively low concentration. Chlorophyll-a concentration varies less during the autumn season (October to December) than spring season (March to June). Water temperature of Bughangang (north Han-river) area was relatively lower in August and higher in November compared with that of other areas. COD and SS concentration showed big regional difference except in November when the concentrations of which were relatively low. The high Chlorophyll-a concentration of April fell conspicuously in rainy season. Gyeongan area, where the water depth is relatively shallow, indicated steep temperature gradient in April compared with that in August or November. High 55 concentration in April at P point characterized surface layer while the opposite was recorded in August. Mixing of upper and lower layers had taken place causing dilution of COD, T-N and T-P concentration in August. This condition was maintained throughout November. Therefore, spring-summer seasons needed more attention for water management countermeasure than summer-autumn seasons.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.84-89
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• 2020

Particulate matters of PM_2.5, particularly focusing on 0.1~1 ㎛ decrease the efficiency of dust-collector due to the brownian-motion. This study is to verify the effect of coagulant on the particle size distributions of potassium and PM_2.5. The activated coagulant was spayed to the coal fired fluidized bed combustion boiler by the weight ratio of 1,200 : 1 = coal : coagulant, and the size distributions of captured particles at both the cyclone (FP) and electrostatic precipitator (EP) were measured. As the result of XRP analysis, the potassium content of FP increased to 13.33% (averagely from 1.65% to 1.87%) and, in EP at 17.68% (averagely from 1.65% to 2.03%). And it was confirmed by the particle size distribution analyzer and SEM image analysis that the distribution rates of PM_2.5 decreased at 89.53% on average in FP, and at 88.57% in EP. The total dust concentration (mg/㎥) confirmed by tele-monitering system (TMS) decreased during the primary test from 2.6 to 1.7~1.9 and also the secondary test from 2.9 to 1.7~1.9.