• Journal of Biosystems Engineering
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• 제35권6호
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• pp.401-407
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• 2010

In this study, computer simulations were conducted to assess the use of a circulating concurrent-flow dryer for rapeseed drying and to determined the effect of this drying method on the germination ratio of rapeseed after the drying process was complete. The simultaneous heat and mass transfer between air and rapeseed in a concurrent-flow dryer was examined by simulation. The drying simulation was based on several parameters with sequent time series. Equations concerning air psychrometrics, physical properties, thermal properties, equilibrium moisture content, thin layer drying of rapeseed, etc. were all combined to solve the simulation models. Based on energy and mass transfer in the concurrent-flow drying model, a simulation program for the circulating concurrent-flow rapeseed dryer was built along with a detailed description of the mathematical solution to the model. A pilot scale circulating concurrent-flow dryer(200 kg/batch) was used to verify the fitness of the simulation program. A comparison between the experimental data and the model predicted results was presented and discussed. The drying parameters and germination ratio were analyzed and the accuracy of the simulation program was evaluated. The simulation program proved to be reliable and was shown to be a convenient tool for predicting rapeseed drying and germination ratio of rapeseed in a concurrent-flow dryer.

• 폴리머
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• 제37권6호
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• pp.685-693
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• 2013

반응 컴파운딩으로 개질한 poly(lactic acid)를 초임계 $CO_2(scCO_2)$를 사용하여 발포하였다. 발포는 $105{\sim}135^{\circ}C$와 12~24 MPa 범위에서 실시하였다. 발포체의 발포 배율과 셀 구조는 온도, 압력 및 감압 속도와 같은 발포 조건에 크게 영향을 받았다. 발포 온도와 포화 압력 증가에 따라서 발포 배율은 증가하다가 감소하였으며, 그 결과로 $120^{\circ}C$ 발포 온도 및 20 MPa 포화 압력에서 최대 발포 배율이 얻어졌다. 감압 속도가 느린 경우에는 셀이 장시간 동안 팽창함으로써 보다 큰 셀 구조를 가지는 발포체가 얻어졌다.

• 한국염색가공학회지
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• 제19권3호
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• pp.26-36
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• 2007

This study was carried out to treat the aqueous solutions containing reactive dyes(RB19, RR120 and RY179) by the Ozone demand flask method and adsorption process using activated carbon fiber(ACF) which are one of the main pollutants in dye wastewater. Ozone oxidation of three kinds of the reactive dyes was examined to investigate the reactivity of dyes with ozone, competition reaction and ozone utilization on various conditions for single- and multi-solute dye solution. Concentration of dyes was decreased continuously with increasing ozone dosage in the single-solute dye solutions. Competition quotient values were calculated to investigate the preferential oxidation of individual dyes in multi-solute dye solutions. Competition quotients(CQi) and values of the overall utilization efficiency, ${\eta}O_3$, were increased at 40mg/l of ozone dosage in multi-solute dye solutions. ACF(A-15) has much larger specific surface area$(1,584m^2/g-ACF)$ in comparison with granular activated carbon adsorbent (F400, $1,125m^2/g-GAC$), which is commonly used, and most of pores were found to be micropores with pore radius of 2nm and below. It was found that RB19 was most easily adsorbed among the dyes in this study. In the case of PCP (p-chlorophenol) and sucrose, which are single component adsorbate, adsorption capacities of ACF(A-15) were in good agreement with the batch adsorption measurement, and saturation time predicted of ACF columns for these components was also well agreed with practically measured time. But in the case of reactive dyes, which have relatively high molecular weight and aggregated with multi-components, adsorption capacities or saturation time predicted were not agreed with practically measured values.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권5호
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• pp.1-6
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• 2013

This study was performed to develop a method for quantitative analysis obtaining the amount of calcium carbonate minerals formed when Ca salts biomimetically reacted with carbon dioxide. There were two methods compared; 1) volumetric calcimeter method that determining the amount of released carbon dioxide after calcium carbonate minerals were acidified by 4N HCl and 2) Thermogravimetry-Differential Thermal Analysis (TG-DTA) adopting differential decomposition temperature breaking-up the structural link within calcium carbonate minerals. The comparisons were made by batch experiment (i.e., biocalcification process) along with control (i.e., nominal concentration of $CaCO_3$ prepared). For the control, TG-DTA took a minor root mean square deviation (RMSD) of 1.1~5.9 mg, whereas volumetric calcimeter exposed a greater RMSD of 28.3 mg. For the biocalcification, the amount of $CaCO_3$ was more precisely obtained for TG-DTA rather than that of volumetric calcimeter. It was decided that TG-DTA was more successfully used for quantitative analysis to observe the amount of calcium carbonate minerals derived from biocalcification.

• 정보보호학회논문지
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• 제31권5호
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• pp.987-999
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• 2021

최근 데이터로 인한 개인정보 침해로 인해 연합학습이 이슈화되고 있다. 연합학습은 학습데이터를 요구하지 않기 때문에 프라이버시 침해로부터 안전하다. 이로 인해 분산된 디바이스, 데이터를 활용하여 효율을 내기 위한 응용 방법에 대한 연구들이 진행되고 있다. 그러나 연합학습과정에서 전송되는 그래디언트로부터 학습데이터를 복원하는 재복원공격에 대한 연구가 진행됨에 따라 더는 연합학습도 안전하다고 볼 수 없다. 본 논문은 다양한 데이터 상황에서 데이터 복원 공격이 얼마나 잘되는지 수치적, 시각적으로 확인하는 것이다. 데이터가 1개만 존재할 때부터 크게는 클래스 안에 데이터가 여러 개 분포해 있을 때로 나누어 재복원공격이 얼마나 되는지 확인을 위해 MSE, LOSS, PSNR, SSIM인 평가지표로 MNIST 데이터를 활용해 수치로 확인한다. 알게 된 사실로 클래스와 데이터가 많아질수록 MSE, LOSS,이 높아지고 PSNR, SSIM이 낮아져 복원성능이 떨어지지만 몇 개의 복원된 이미지로 충분히 프라이버시 침해가 가능하다는 것을 확인할 수 있다.

• 한국축산식품학회지
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• 제41권6호
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• pp.1078-1094
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• 2021

This research investigated the physio-chemical and microbial quality characteristics of dry fermented sausage from selected Pediococcus strains: P. acidiliactici (PE1) and P. pentosaceus (PE2) as compared to commercial starter culture (COS) during fermentation and ripening. Treatments showed no substantial variation (p<0.05) in water activity (a_w) values across the study period. PE1 and PE2 treatments exhibited similar (p>0.05) pH values and presented remarkable (p<0.05) lower volatile basic nitrogen (VBN) and thiobarbituric acid reactive (TBARS) content than COS treatment throughout the ripening period. However, the pH values in COS batch were considerably lower than others. PE1 samples presented a significant highest (p<0.05) counts both in lactic acid bacteria (LAB) and total plate count (TPC) than COS and PE2 treatments at 7 days fermentation, and it resulted in a similar and higher TPC count as COS after the ripening period. After the ripening process, treatments are ordered based on LAB counts as follows: COS>PE1>PE2. All batches presented similar redness and yellowness attributes since the 7 days of fermentation and in lightness across the study period. Treatments were similar (p>0.05) in springiness and chewiness traits across the study period and in hardness characteristics in the ripened products. Cohesiveness was higher in PE1 and COS batches. No variation (p>0.05) in aroma and sourness sensory attributes of treatments. The color attribute was highest (p<0.05) in PE1 and PE2 treatments and PE1 had the highest overall acceptability. The overall outstanding merit exhibited by PE1 can be utilized in the commercial production of high-quality dry fermented sausage.

• 한국융합학회논문지
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• 제12권10호
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• pp.71-79
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• 2021

제조업 분야에서는 경쟁력 강화를 위하여 다품종 생산으로의 전환이 이루어지고 있으며, 하이브리드 제조기술이 증가하고 있다. 특히 제조실행시스템과 ERP 등의 도입을 통하여 생산 품질 향상에 많은 노력을 기울이고 있기에, 신속하고 효과적인 관리를 위한 MES 운영이 필요하다. MES는 제품 생산과 관련된 모든 단계를 관리하면서, 생산 활동에 비효율적인 부분은 개선하고, 공정 변경의 경우에 시스템에 변경 사항을 반영해야 한다. 그러나 대부분의 MES는 시스템 관리자를 통하여 수동적이고, 반복적으로 비효율적인 작업을 계속 하고 있는 상황이다. 본 논문에서는 생산과 관련된 요구사항을 시스템 관리자가 특정 라인의 장비에 대한 참조 정보를, 다른 라인의 동일한 장비에도 일괄 적용할 수 있는 모델을 제안한다. 제안 모델을 통하여 참조 정보의 일괄 적용과 선택 적용의 구분으로 생산 라인에 대한 유연한 대처가 가능할 것으로 기대된다.

• 한국시뮬레이션학회논문지
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• 제30권4호
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• pp.1-8
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• 2021

복잡하고 비선형적인 특징을 갖는 시계열 데이터를 예측하기 위해 딥러닝 기법이 널리 사용되고 있다. 본 연구에서는 최근에 개발된 WaveNet을 개선하고 워크포워드 검증 기법을 적용하여 전력 소비량 데이터를 24시간 이전에 예측하고자 한다. 원래 WaveNet은 오디오 데이터 예측에 사용하고자 고안되었으며, 장기간의 데이터를 효과적으로 예측하기 위해 1차원 팽창인과 합성곱(1D dilated causal convolution)을 사용한다. 먼저, WaveNet이 부호화된 정수 값이 아니라 실수 값을 출력하여 전력 데이터를 예측하기 적합하도록 개선하였다. 다음으로 학습 과정에 적용된 하이퍼파라미터(입력 기간, 배치 크기, WaveNet 블록 개수, 팽창 비율, 학습률 변경)를 조정하여 적절한 성능을 나타내도록 하였다. 마지막으로 성능 평가를 통해 전통적인 홀드아웃 검증 기법보다 본 연구에서 사용한 워크포워드 검증 기법이 전력 소비량 데이터 예측에 우수함 성능을 나타냄을 확인하였다.

• 상하수도학회지
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• 제33권2호
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• pp.111-119
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• 2019

Electro-coagulation process has been gained an attention recently because it could overcome the membrane fouling problems in MBR(Membrane bio-reactor). Effect of the key operational parameters in electro-coagulation, current density(${\rho}_i$) and contact time(t) on membrane fouling reduction was investigated in this study. A kinetic model for ${\rho}_i$ and t required to reduce the membrane fouling was suggested under different MLSS(mixed liquor suspended solids) concentration. Total 48 batch type experiments of electro-coagulations under different sets of current densities(2.5, 6, 12 and $24A/m^2$), contact times(0, 2, 6 and 12 hr) and MLSS concentration(4500, 6500 and 8500mg/L) were carried out. After each electro-coagulation under different conditions, a series of membrane filtration was performed to get information on how much of membrane fouling was reduced. The membrane fouling decreased as the ${\rho}_i$ and t increased but as MLSS decreased. Total fouling resistances, Rt (=Rc+Rf) were calculated and compared to those of the controls (Ro), which were obtained from the experiments without electro-coagulation. A kinetic approach for the fouling reduction rate (Rt/Ro) was carried out and three equations under different MLSS concentration were suggested: i) ${\rho}_i^{0.39}t=3.5$ (MLSS=4500 mg/L), ii) ${\rho}_i^{0.46}t=7.0$ (MLSS=6500 mg/L), iii) ${\rho}_i^{0.74}t=10.5$ (MLSS=8500 mg/L). These equations state that the product of ${\rho}_i$ and t needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

• 자원리싸이클링
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• 제29권6호
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• pp.41-47
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• 2020

본 연구는 유동층 석탄보일러에서 발생하는 석탄 바닥회를 중금속 처리제로 활용하기 위하여 수행하였으며, 산성광산배수 중의 중금속 성분을 제거하기 위한 실험을 실시하였다. 대상 중금속은 구리, 카드뮴, 크롬, 납으로 선정하여 산성광산배수 모사액을 제조하였고, 석탄회 첨가량, 시험용액의 초기 중금속 농도에 대한 제거실험을 실시하였다. 실험결과, 석탄회 농도가 중량물 시료 15 g/L, 경량물 시료 10 g/L로 첨가된 조건에서 총 중금속의 제거능은 각각 30.8 mg/L, 46.4 mg/g로 나타났다. 이후 비소를 추가하여 5종 중금속에 대한 최대 제거능을 파악하기 위하여 장기 컬럼실험을 실시하였으며, 각각의 중금속 성분에 대한 제거능을 조사하였고, 약 60일간 가동 후 pH 9.25에서 최대 중금속 제거능은 23.6 mg/g이었다.