• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.66-73
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• 2018

A computational fluid dynamics simulation of pyrotechnic material combustion inside a cylindrical closed vessel was carried out using the Eulerian-Lagrangian method. The 5th order upwind WENO scheme and the improved delayed detached eddy turbulence model were implemented to capture shock waves. The flow structure was analyzed inside the cylindrical vessel with a pressure sensor installed at the side wall center. The analysis revealed that the pressure oscillated because of the shock wave vibration. Additionally, the simulation results with four different sensor tab depths implied that, inside the sensor tab, eddies were generated by the excessively large gap between the sensor diaphragm and the side wall. These eddies caused irregularity to the measured time-pressure curve, which is an undesirable characteristic.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.100-107
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• 2021

As a significant technology in the smartization era promoted by the Fourth Industrial Revolution, the secondary battery industry has recently attracted significant attention. The demand for lithium-ion batteries (LIBs), which exhibit excellent performance, is considerably increasing in different industrial fields. During the manufacturing process of LIBs, it is necessary to join the cathode and anode sheets with thicknesses of several tens of micrometers to lead taps of the cathode and anode with thicknesses of several hundreds of micrometers. Ultrasonic welding exhibits excellent bonding when bonded with very thin plates, such as negative and positive electrodes of LIBs, and dissimilar and highly conductive materials. In addition, ultrasonic welding has a small heat-affected zone. In LIBs, Cu is mainly used as the negative electrode sheet, whereas Cu or Ni is used as the negative electrode tab. In this study, one or two electrode sheets (t0.025 mm Cu) were welded to one lead tab (t0.1 mm Cu). The welding energy and pressure were used as welding parameters to determine the welding strength of the interface between two or three welded materials. Finally, the effects of these welding parameters on the welding strength were investigated.

• Journal of the FoodService Safety
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• v.3 no.1
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• pp.8-18
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• 2022

Dry-aging is one of the traditional aging processes, especially for beef. This aging process is being popular, because it produces unique brown/roasted flavor and texture that consumers prefer. However, as it is exposed to outside without packaging food safety concerns have been raised. The objective of this study was to investigate the presence of total aerobic bacteria (TAB) and pathogenic bacteria in manufacturing environment and suggest the safety management plan for the production of dry-aged meat. Surface samples from 66 environmental and 6 beef carcass samples were collected. According to the monitoring results, the contamination levels of TAB were in the order of shelves (5.4±1.1 Log CFU/cm²), cotton gloves (2.9±0.2 Log CFU/cm²), and door knobs (2.8±0.4 Log CFU/cm²) in the dry-aging room. In the door knobs, the level of mold was higher than that of yeast. These results indicate that the mold spores may be cross-contaminated with environmental factors inside the aging room. The risk factors that may occur during the manufacturing process were presented and possibility of risk was determined. From the aspect of microbiology, aging and trimming steps were determined as the critical control points. The temperature of the aging room should be maintained below 10℃ and the humidity below 75-85%. Based on the monitoring and the risk assessment of the dry-aging process, we prepared the safety management plan for the production of dry-aged meat, and it should be useful in improving the food safety of dry-aged meat.

• Animal Bioscience
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• v.35 no.12
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• pp.1957-1966
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• 2022

Objective: This study aimed to evaluate the difference in the thigh meat quality of Ross 308 broiler from conventional and welfare farms. Methods: Thigh meat samples of Ross 308 broilers (age, 35 d; carcass weight, 1.1 kg) from conventional farm (RCF, n = 60) and animal welfare farms (RAWF, n = 60) were analyzed. Proximate composition, pH, color (lightness, redness, and yellowness), water-holding capacity (WHC), shear force, total aerobic bacteria (TAB), and volatile basic nitrogen (VBN) were measured and the levels of bioactive compounds such as dipeptides (anserine and carnosine), creatine, creatinine, and their anti-oxidation activity were determined. Results: The RCF and RAWF did not differ significantly in their proximate composition, WHC, color, and creatine and carnosine levels. The pH value was significantly lower in RAWF than in RCF on day 7. The shear force value was significantly higher in RAWF than in RCF throughout the storage duration. TAB in RCF on day 9 were significantly higher than those in RAWF. The VBN content of RAWF was significantly lower than that of RCF after 5 days of storage. Creatinine content was significantly higher in RAWF (3.50 mg/100 g) than in RCF (3.08 mg/100 g) on day 1. Along with higher carnosine and anserine contents of RAWF, it had significantly higher 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities than those of RCF. Conclusion: These results imply that the animal welfare farming system beneficially affects the overall oxidative stability of Ross 308 thigh meat.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.119-124
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• 2023

Deep learning has recently demonstrated conspicuous efficacy across diverse domains than traditional machine learning techniques, as the most popular approach for pattern recognition. The classification problems for tabular data, however, are remain for the area of traditional machine learning. This paper introduces a novel network module designed to tabular data into high-dimensional tensors. The module is integrated into conventional deep learning networks and subsequently applied to the classification of structured data. The proposed method undergoes training and validation on four datasets, culminating in an average accuracy of 90.22%. Notably, this performance surpasses that of the contemporary deep learning model, TabNet, by 2.55%p. The proposed approach acquires significance by virtue of its capacity to harness diverse network architectures, renowned for their superior performance in the domain of computer vision, for the analysis of tabular data.

• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.797-810
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• 2023

The shape of the male beard to be examined in this study was set as a mustache. This study used frequency analysis and cross-tab analysis to conduct T-test and one-way variance analysis using 300 final responses from the questionnaire that presented preference and non-preference reasons and demographic characteristics along with preference and non-preference options to measure the likability of whiskers. As a result of the study, there were differences in men's preference and non-preference for each beard formulation, and the level of difference was statistically significant between the male and female groups and the age group. In addition, it was found that each group category showed a difference in the reasons for judging likes/dislikes by beard form. There are differences in preference and non-preference according to men's beard formations, and it was confirmed that there are various differences according to perceptual characteristics in the main reasons for favorability and dislike, which are the basis for judgment. Through these results, academic and practical implications were presented in the field of beauty.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.41-50
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• 2003

Numerical analysis was carried out to investigate performance and combustion characteristics of KSR-III liquid rocket engine with several types of baffle. To evaluate the change of performance and combustion characteristics with several types of baffle, the first numerical calculations were performed about baffle tab, radial blade baffle, and hub-and-spoke baffle. Then radial blade and hub-and-spoke baffle were determined to design two types of the KSR-III engine with baffles. Also to investigate the effect of injector arrangements and baffle positions, two types of radial blade baffle were calculated then numerical calculations were carried out with changing axial length of radial blade I, II and hub-and-spoke baffle. While axial length of baffle effected to performance very small, injector arrangement effected to performance largely through calculations of radial blade I, II. From the viewpoint of combustion instability, hub-and-spoke baffle controlled combustion instability effectively and there was the performance of hub-and-spoke baffle between radial blade I and II.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.23-35
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• 2015

When people stands near someone's mobile device, it can easily be seen by others. To rephrase this, attackers use human psychology to earn personal information or credit information or other. People are exposed by social engineering attacks. It is certain that we need more than just recommendation for the security to avoid social engineering attacks. This is why I proposed this paper. In this paper, I proposed an authentication technique using NFC and Hash function to stand against social engineering attack. Proposed technique result is showing that it could prevent shoulder surfing, touch event information, spyware attack using screen capture and smudge attack which relies on detecting the oily smudges left behind by user's fingers. Besides smart phone, IPad, Galaxy tab, Galaxy note and more mobile devices has released and releasing. And also, these mobile devices usage rate is increasing widely. We need to attend these matters and study in depth.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.73-74
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• 2016

This paper proposes a wide output range AC/DC converter for a rechargeable battery of electric vehicle. In the proposed wide output range AC/DC converter for rechargeable battery of electric vehicle, the main transformer in the DC/DC stage is divided by two. Therefore, if the switch is connected to the middle tap, then half of the maximum voltage is applied. Otherwise, it can be applied the full range of the high voltage by connecting the switch to the whole tab. And also, it is designed to have a wide output voltage range by applying Vin/2 made by changing the full-bridge to half-bridge by using the bridge change switch of the input stage. As it can be supplied the wide range output voltage with a single module, it has the advantage of space utilization and cost reduction effect.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.672-675
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• 2003

The development of information ＆ technology and the Internet provides various connecting routes between manufacturers with consumers. These expanded routes has made it Possible fer customers to directly transfer their voice to manufacturers, but n research on how the manufacturers respond the customers' needs has to be further conducted. In this paper, a method in which a best supplier would be chosen based on customers' needs from the perspective of a buyer tab been Presented. A method that makes it possible to evaluate and choose the best supplier in accordance with consumers' requirement by analyzing customers' needs and the evaluated data also hag been designed.