• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.258-262
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• 2019

Although the chemical compositions and biological characteristics of some species of garlic have been investigated, data on Koara garlic are currently lacking. In order to investigate the major compounds and antimicrobial activity of Koara garlic, which was registered as a cultivar in 2012, it was cultivated in Seogwipo, Damyang, and Namhae. Analysis of the chemical composition of the cultivated garlic showed that the alliin, pyruvate contents, and antimicrobial activity were high in garlic grown in Seogwipo ($9.44{\pm}0.28mg/g$, $127.52{\pm}5.50{\mu}M/g$, and 0.31-1.25%, respectively). The total phenol content and reducing sugar contents were abundant in garlic grown in Namhae ($82.23{\pm}0.00g\;GAE/100g$ and $28.59{\pm}0.54mg\;GE/g$, respectively), and the total flavonoid content was high in garlic grown in Damyang ($22.41{\pm}0.77g\;QE/100g$). Although garlics grown in different cultivation areas had different chemical compositions, major compound contents and biological activities of Koara garlic were similar to those of other garlic varieties reported so far. These data will be useful for local farmers, distributors, and consumers.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.107-114
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• 2019

This study analyzes the effect of the accuracy of future management performance, which managers voluntarily announce in the previous year's disclosure, on managers compensation. In the case of a company that disclosed the bad news in the previous year, the ability to predict uncertain future will be more important, and expects executives with better predictability to receive more compensation. The results of this study show that there is a significant negative(-) relationship between the accuracy of the manager's earnings forecast and the performance - compensation of the firms that disclosed the bad news in the previous year. The accuracy of the manager's disclosure is important, and it is confirmed that the manager's compensation increases as the incentive of the manager's effort to reduce future uncertainty. The results of this study are as follows: there is a positive relationship between the managerial performance and the managerial competence of managers. It is important to note that there is a difference and that we have identified additional determinants of the manager compensation contract.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.59-60
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• 2013

Infobutton is an important concept from long time in use and much has been done with respect to its standardization and context supplementation. The concept is to create contextual links to information resources from within the information systems usually health information systems. The need which has been realized by the authors of this paper is the augmentation of Infobuttons from the level of only information links to the level of knowledge links. The authors proposed the concept of knowledge links named as "Knowledgebuttons" which complements the concept Infobuttons. It adds further capabilities of getting knowledge to the users instead of just connectivity to information resources. The better representation of the information retrieved with Infobuttons is the first and foundation step to achieve the goal of getting knowledge. This paper discusses about the concept and applicability of Knowledgebuttons in health information systems. It is envisioned that this concept will add to the overall quality of patient care. Both physicians and patients can benefit from this technique as per their needs. Physicians can help in patient diagnosis and treatment critical decisions while patients can educate them to know more about their health conditions by studying the right knowledge at right time. Knowledgebuttons are able to create a true learning environment for the users while using health information systems.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.99-105
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• 2022

In China, with the rise of third-party payments such as WeChat Pay and Alipay, the traditional business of banks has been greatly affected. Banks can encourage and expand QR code payments to merchants. Therefore, it is meaningful to analyze and study the QR code work of banks. The purpose of this study is to analyze the effect of the execution of the zero-rate of the comprehensive payment QR code combined with the payment cycle and Funds Transfer Pricing (FTP) on commercial banks in China. Based on the manually collected customer data of Chinese commercial banks, this paper conducts a case analysis combined with the calculation method of financial indicators. As a result of the study, it was found that commercial banks need to continue to implement the policy as the advantages of introducing the integrated QR code fee rate 0 policy are greater than the disadvantages. This paper provides feasible suggestions on how to quickly occupy the offline payment market for commercial banks, which has guiding significance for commercial banks' marketing decisions. Presently, there are few studies on the zero-rate subsidy policy implemented by Chinese commercial banks.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.381-386
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• 2022

This paper details the analytical and experimental studies performed to propose a steel damper based on the flexural yielding mechanism. The damper is composed of a set of damping plates that are designed to yield in flexure. The comparison of experimental and finite element analysis results indicate that the analytical approach adopted in this study should be appropriate to perform sensitivity studies on the geometries of the damping plates. Although the damper is originally proposed to work based on the flexural mechanism, it is observed that the contribution of the tensile behavior of the damping plate could be considerable. As the thickness of the damping plate increases, the plastic energy due to the flexural yield increases. As the thickness of the damping plate decreases, the contribution of the tensile behavior increases, and the shape of the hysteresis loop distorts.

• Journal of the Korean Applied Science and Technology
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• v.40 no.1
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• pp.179-187
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• 2023

Nanogenerators containing biomaterials are eco-friendly electronic devices in terms of being a non-polluting energy source and biodegradable electronic waste. In particular, the amount of waste will be also reduced if the biomaterial can be extracted from biowaste. In this study, a triboelectric nanogenerator was fabricated using animal collagen present in the skin of a mammal and its characteristion was proformed. The electro-anodic layer of the triboelectric nanogenerator was constructed by forming a collagen film using the spin coating method, and it was confirmed that the film was porous from scanning electron microscopy. The fabricated triboelectric nanogenerator exhibited an open-circuit voltage from 7 V at 3 Hz to 15 V at 5 Hz due to periodic mechanical movement, and a short-circuit current of 3.8 uA at 5 Hz. In conclusion, collagen-containing triboelectric nanogenerators can be power source for low-power operating devices such as sensors and are also expected to be useful for reducing electronic waste.

• Composites Research
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• v.22 no.4
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• pp.41-49
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• 2009

Natural fiber reinforced composites are emerging as low-cost, lightweight, recyclable, and eco-friendly materials. These are biodegradable and non-abrasive. Due to eco-friendly and biodegradable characteristics of natural fibers, they are being considered as potential candidates to replace the conventional fibers. The chemical, mechanical, and physical properties of natural fibers have distinct features depending upon the cellulose content of the fibers which varies from fiber to fiber. The mechanical properties of composites are influenced mainly by the adhesion between matrix and fibers. Several chemical and physical modification methods of fiber surface were incorporated to improve the tiber-matrix adhesion resulting in the enhancement of mechanical properties of the composites. This paper outlines the works reported on natural tiber reinforced composites with special reference to the type of fibers, polymer matrix, processing techniques, treatment of fibers, and fiber-matrix interface.

• Journal of the Economic Geographical Society of Korea
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• v.27 no.1
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• pp.53-73
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• 2024

While global production supply chains are expected to shift toward friendly or allied countries, pandemic-shoring such as nearshoring and friendshoring, due to increased protectionism and the reorganization of regional value chains in the wake of the global pandemic, the study found that economic rather than political factors are still at play in consumer supply chains. In the case of Chinese e-commerce market (C-commerce), the study attributes the rapid growth of the market to (1) related regulatory relaxations introduced to stimulate consumption after the end of COVID-19, (2) an increasing pattern of wanting to consume more for a limited income and (3) unconventional business activities to increase their share of the global consumption market. Through these phenomena, the production-consumption network is likely to develop into a more fragmented form, and the consumption network in particular is expected to become more fragmented, influenced by the digital technology war, a phenomenon of re-globalization.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.54-54
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• 2017

본 연구는 무인 헬리콥터의 양력을 개선하기 위한 기초 단계로서 V1505A 및 V2008B 기본 두 익형의 400 mm 블레이드 섹션에 해당하는 모델에 대한 풍동실험을 실시하여 양력, 항력 및 동력특성을 분석하고 CFD 시뮬레이션의 결과와 비교하고 검증하였다. 시뮬레이션은 풍동 실험과 유사하게 설정하기 위하여 400 mm 블레이드 섹션의 양 끝을 벽으로 제한하여 3차원 와류현상을 억제하여 모델을 구성하였고, 시뮬레이션의 결과와 비교하여 모델을 검증하였다. 사용된 모델은 로터로부터 $Re=0.32{\times}10^6$ 영역까지는 aminar 모델을 사용하였으며, 그 이후 영역역(>$Re=0.32{\times}10^6$)은 양력 및 저항의 급격한 변화를 올바로 포착할 수 있다는 S-A 모델을 적용하여 확장하였다. 시뮬레이션의 격자는 유동 현상에 있어 박리로 야기된 와류 현상을 관찰하기 위하여 익형 주변에 접하는 부분에 격자를 집중시켰다. 시뮬레이션 방법은 유속은 36~141 m/s 까지 5 수준으로 하였으며, 받음각은 $0{\sim}16^{\circ}$로 7 수준으로 변화 시키면서 공력계수 및 동력을 분석하였다. 양력분석에 있어 익형 V1505A에 비해 익형 V2008B의 특성이 우수하였으나, 익형 V1505A는 실속 이후 양력이 급격히 떨어지지 않고 유지되는 특성을 보였다. 익형 V2008B는 낮은 받음각에서 높은 공력과 낮은 항력을 나타냈다. 동력 분석 결과로 익형 V1505A의 유도동력은 총 동력의 56~72%를 차지하고, 형상동력은 총 동력의 27~43%를 차지하였다. 익형 V2008B는 유도동력은 총 동력의 66~81%를 차지하고, 형상동력은 총 동력의 18~33%를 차지하였다. 익형 V2008B이 익형 V1505A보다 유도동력은 크며, 형상동력은 적게 나와 상대적으로 효율적이라 할 수 있다. 헬리콥터 동력원의 규모는 법률적인 총중량에 의하여 제한되므로 일반적인 농용 소형 무인 헬리콥터 엔진의 사양인 24.5 kW (32PS)를 적용한다면, 익형 V1505A은 받음각 $8{\sim}10^{\circ}$에서 그리고 익형 V2008B은 $7{\sim}9^{\circ}$정도에서 받음각이 제한되며 이때 총 양력은 1200~1300 N 정도로 예상된다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.59-59
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• 2017

무인 헬리콥터의 양력을 개선하기 위한 익형 설계 단계로서 두꺼운 익형(V1505A)과 얇고 처진 익형(V2008B)의 기본 두 익형의 특성을 예측하는데 있어 회전하는 블레이드의 현실적 조건을 반영한 3D 모델을 마련하고 성능을 예측하였다. Fluent를 이용한 400 mm 선형모델의 시뮬레이션에서는 V1505A 익형은 높은 받음각에서 안정적인 특성을 보인 반면 V2008B는 비교적 높은 동력효율 특성을 보였으나, 높은 받음각에서는 실속 이후 양력이 급락하는 특성을 나타낸다. 형성된 노드 수는 약 870,000개로 하였다. 시위길이 135 mm인 익형 V2008B의 형상은 ANSYS (Fluent v16.2)를 이용해 반경(길이) 1,502 (1,380) mm 의 로터 블레이드를 구성하였다. 충분하지 않은 유동장이 익형 표면에서의 유동의 영향에 영향을 주지 않도록 직경 20 m의 원방경계(far field)를 형성하였다. 사용된 매쉬의 형태는 정사면체 형태로 로터 표면으로부터의 첫 번째 두께 높이는 0.001 m이고 10개의 층으로 형성하였다. 정지 비행하는 헬리콥터의 상태를 가정하여 회전좌표계를 이용하여 정상상태의 유동을 해석하고 사용된 난류모델은 넓은 영역에서의 유동을 고려하여 Realizable $k-{\varepsilon}$ 모델을 사용하였다. 내측그립 받음각 $6{\sim}22^{\circ}$에 대하여 현실적인 회전속도를 연동하여 600~1000 rpm을 적용하였다. 반복수(iteration)는 2000으로 하여 잔차값(residual)이 충분히 수렴하도록 하였다. 전체적으로 실제 헬리콥터가 발휘하는 양력보다는 낮은 수치로 예측되었으며 모델 및 해석 조건에 대한 검토가 필요해 보인다. 양력 값은 받음각 $10^{\circ}$에서 자중(약 68 kgf)을 극복하였고 받음각 $12^{\circ}$에 유상하중 20 kgf을 발휘하며 888 N의 양력을 보였다, 이어 받음각 $22^{\circ}$에서 실속 현상이 발생하였다. 받음각이 증가함에 따라 항력 역시 증가하였으며 받음각 $12^{\circ}$에서 121 N이었고 실속에 이르며 항력은 갑자기 증가할 것으로 예측된다. 본 연구는 변이 익형 개발의 선행 단계로 기본 익형에 대한 공력특성을 CFD 시뮬레이션을 통하여 예측하였다. 예측 값은 현실적 실험방법을 통하여 검증이 되어야 하며 이후 변이익형에 대한 예측과 설계가 가능하다.