• KIEAE Journal
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• v.5 no.3
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• pp.41-48
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• 2005

Before occupation of an apartment housing, the builders are required to inform the test result of IAQ to the public. However, there is no simplified method to predict IAQ before measurement of pollutant concentration. In this study, a simplified way of predicting IAQ based on the distribution of indoor pollutant concentration is proposed. 7 different cases of air change rate have been simulated through CFD analysis to get the distribution ratio of each pollutant material and then simplified functions were used with CRIAQ1 values derived from CFD simulation to evaluate by comparing the influence of each material in the indoor pollutant concentration. Again, a lot of efforts which can improve the indoor air quality have been performed. Materials used in indoor space are labeled with their pollutant emission level. Installation of ventilation system in residential buildings will be regulated by a building codes sooner or later. But it is important to understand the fact that layout of walls, location or size of openings will influence the indoor air flow and pollutant concentration. And location of emitting material influences to indoor air pollutants distribution. But until now there is few recognition and consideration of these factors. Therefore, in this paper the effects of these factors is proved and some kind of guideline is made for designers after a comparison of typical apartment floor plan and a new type plan with their average pollutant concentration and its distribution of each room. CFD(Computational Fluid Dynamics) program was used to show the indoor air flow and pollutant concentration distribution. For this purpose, a typical $100m^2$ apartment floor plan was chosen as a case study model and several alternatives were reviewed to improve the IAQ performance. The simulation took place in the condition of natural ventilation through windows.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.168-180
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• 2018

In order to achieve the high quality output voltage of single-phase voltage source inverters, in this paper an Adaptive Complementary Sliding Mode Control (ACSMC) is proposed. Firstly, the dynamics model of the single-phase inverter with lumped uncertainty including parameter variations and external disturbances is derived. Then, the conventional Sliding Mode Control (SMC) and Complementary Sliding Mode Control (CSMC) are introduced separately. However, when system parameters vary or external disturbance occurs, the controlling performance such as tracking error, response speed et al. always could not satisfy the requirements based on the SMC and CSMC methods. Consequently, an ACSMC is developed. The ACSMC is composed of a CSMC term, a compensating control term and a filter parameters estimator. The compensating control term is applied to compensate for the system uncertainties, the filter parameters estimator is used for on-line LC parameter estimation by the proposed adaptive law. The adaptive law is derived using the Lyapunov theorem to guarantee the closed-loop stability. In order to decrease the control system cost, an inductor current estimator is developed. Finally, the effectiveness of the proposed controller is validated through Matlab/Simulink and experiments on a prototype single-phase inverter test bed with a TMS320LF28335 DSP. The simulation and experimental results show that compared to the conventional SMC and CSMC, the proposed ACSMC control strategy achieves more excellent performance such as fast transient response, small steady-state error, and low total harmonic distortion no matter under load step change, nonlinear load with inductor parameter variation or external disturbance.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.365-370
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• 2005

Many sea accidents such as collisions and groundings of vessels were occurred due to the lack of sufficient manoeuvring capability of vessels. Therefore IMO adopted 'The interim standards of ship manoeuvrability by Resolution A.751(18)' and the standards have been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless qf the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standards are divided into three kinds as bellows; (1) Turning capability standards : Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standards : Estimated values in design stage are to be certified by $10^{\circ}\;and\;20^{\circ}$ Zig-Zag tests of the actual vessel. (3) Shortest stopping distance standards : Estimated values in design stage are to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors computed the values of the manoeuvring standards of several vessels from their original design and compared them with those results from experiments of the model ships and also examined the values and concluded about the validity of IMO manoeuvrability standards.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.277-283
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• 2020

In a concentric magnetic gear, which replaces the teeth of a mechanical gear with a permanent magnet, the polar ratio of the magnet that determines the reduction ratio affects the behavior of the magnetic gear dramatically. This study analyzed the density of transmission torque, the efficiency of torque considering the solid loss, and the torque quality, including the cogging characteristics using finite element analysis. When the pole number on the driving side was changed from two to five, it was confirmed that there was an optimal pole ratio, in which the transmission torque was maximized. Because eddy current generation density is proportional to the magnetic field, the transmission efficiency also shows a similar tendency to the transmission torque density, and the efficiency is more than 95% at a low gear ratio. The cogging characteristics due to the interaction of the permanent magnets with the limited number of poles are inversely proportional to the least common multiple between the number of magnets on the drive side and the number of modulator teeth. A test model was built for the transmission torque evaluation.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1251-1264
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• 2018

The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.575-580
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• 2014

Model gel food samples of yanggaeng (Y) were prepared for the elderly with various gelling agents, including agar (AG), low acyl gellan (GL), ${\kappa}$-carrageenan (CA), locust bean gum (LB), glucomannan (GM), and xanthan gum (XA) in different combinations as follows (in 1:1 ratio): LB+CA, GM+XA, and GM+CA. The quality characteristics of the different combinations were compared. The results revealed that water loss was highest for Y-GL, whereas there was no significant difference among the other samples. Y-GL showed the highest values for lightness in color, whereas Y-AG showed the lowest. Regarding textural properties, Y-LB+CA had the highest hardness value, whereas Y-GL had the lowest; the hardness of Y was related to the cross-section of the added gel. Finally, Y-GM+XA exhibited the highest score in overall acceptability in the sensory test by elderly, indicating that the preferable texture by elderly is slightly chewy, but not adhesive.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.87-87
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• 2019

The consumption of herbal medicine and related products (herbal products) have increased in South Korea. At the same time the quality, safety, and efficacy of herbal products is being raised. Currently, the herbal products are standardized and controlled according to the requirements of the Korean Pharmacopoeia, the National Institute of Health and the Ministry of Public Health and Social Affairs. The validation of herbal products and their medicinal component is important, since many of these herbal products are composed of two or more medicinal plants. However, there are no tools to support the validation process. Interest in deep learning has exploded over the past decade, for herbal medicine using algorithms to achieve herb recognition, symptom related target prediction, and drug repositioning have been reported. In this study, individual images of four herbs (Panax ginseng C.A. Meyer, Atractylodes macrocephala Koidz, Poria cocos Wolf, Glycyrrhiza uralensis Fischer), actually sold in the market, were achieved. Certain image preprocessing steps such as noise reduction and resize were formatted. After the features are optimized, we applied GoogLeNet_Inception v4 model for herb image recognition. Experimental results show that our method achieved test accuracy of 95%. However, there are two limitations in the current study. Firstly, due to the relatively small data collection (100 images), the training loss is much lower than validation loss which possess overfitting problem. Secondly, herbal products are mostly in a mixture, the applied method cannot be reliable to detect a single herb from a mixture. Thus, further large data collection and improved object detection is needed for better classification.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.1
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• pp.9-16
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• 2021

The present study was conducted to accomplish management efficiency by preparing preemptive measures for consumer dissatisfaction and overcome risks caused by Global Warming through studies of model cases in packaging. Through this study, we made it possible to find a way for companies to prepare for Global warming and consumer dissatisfaction. By contributing to eco-friendly packaging, we are trying to preemptively respond to recent major issues through packaging. Through this experiment, we tried to measure the degree of penetration of Plodia interpunctella H. larva into the insect repellent film produced by printing Ink containing a natural repellent. The control experiment was conducted with an untreated LDPE film to which no insect repellent was applied. The numbers decreased from 17 to 7 when the film was processed with repellent to show experimental results verifying effects of repellent by decrease in 10 (58.8% Decrease). Such results show that it is safe when the film is unfolded but in the case where the film is folded, the Plodia interpunctella H. punches through the film to lead to consumer dissatisfaction and it suggests that this can bring on risks to corporate management. Considering that most of the film is folded in the case of PE bag packaging, the direction which the corporations should take in terms of preparing for climate change countermeasures and consumer dissatisfaction has been clarified. Due to it receiving satisfactory results in safety rest results for printing film applied with pest repellent as well as the Quality analysis to test repellent contents of repellent film, it is certain that the importance of repellent method in packaging will increase in preparing for consumer dissatisfaction and actions against climate change henceforth.

• Food Engineering Progress
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• v.15 no.3
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• pp.269-275
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• 2011

The baking performance of yacon powder as a value-added food ingredient was investigated in a model system of sponge cakes. Yacon powder was incorporated into cake batter at 5 levels (0, 10, 20, and 30%, w/w) by replacing equivalent amount of wheat flour. The specific gravity of batter increased significantly while pH decreased significantly with the increase in yacon powder content (p < 0.05). The specific volume and moisture content of sponge cakes decreased while baking loss increased (p < 0.05). Volume of the cakes decreased with higher amount of yacon powder in the formulation as indicated by the decrease in the volume index. The symmetry index was not affected by the amount of yacon powder in the formulation (p > 0.05). Sponge cakes became darker and firmer with increase in yacon powder content (p < 0.05). Finally, the consumer acceptance test indicated that incorporation of yacon powder up to 20% in the formulation of sponge cakes did not significantly influence the consumers' overall acceptability.

• Entomological Research
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• v.48 no.6
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• pp.533-539
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• 2018

The RNA interference (RNAi) has been considered as an important genetic tool and applied to develop a new living modified (LM) crop trait which is an improvement of nutrient quality or pest management. The RNAi of DvSnf7 has been used for resistance to LM maize and the Western Corn Rootworm which is a major agricultural pest for the US Corn Belt. Most of the environmental risk assessments (ERA) of double strand RNA (dsRNA) have been performed using in vitro transcript products, and not in vivo expressed product. A large amount of dsRNA was required for the acute toxicity assay of water fleas. Therefore development of massive dsRNA purification techniques is critical. Daphnia, a freshwater microcrustacean, is a model organism for studying cellular and molecular mechanism involved in life history traits and ecotoxicology. In this study, we established the massive dsRNA purification method using Escherichia coli and implemented acute toxicity assays to Daphnia magna. As a result, the present RNase A and DNase I, dsRNA was efficiently purified without any special techniques or equipment. Even though purified dsRNA existed during the acute toxicity test, lethality or abnormal behavior were not observed in D. magna. These results indicated that GFP and DvSnf7 dsRNA were not significantly affected to D. magna due to their lack of sequence matching in its genome. The purification method of dsRNA and the acute toxicity assay of water fleas using purified dsRNA would be suitable for the toxicological studies of LMOs to aquatic non-target organisms.