• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.425-435
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• 2017

Structural analysis is used not only for large enterprises, but also for small and medium sized ones, as a necessary procedure for strengthening the certification process for product delivery and shortening the time in the process from concept design to detailed design. Open-source solvers that can be used atlow cost differ from commercial solvers. If there is a problem with the input data, such as with the grid, errors or failures can occur in the calculation step. In this paper, we propose a pre- and post-processor that can be easily applied to the analysis of mechanical structural problems by using the existing structural analysis open source solver (Caculix, Code_Aster). In particular, we propose algorithms for analyzing different types of data using open source solvers in order to extract and generate accurate information,such as 3D models, grids and simulation conditions, and develop and apply information analysis. In addition, to improve the accuracy of open source solvers and to prevent errors, we created a grid that matches the solver characteristics and developed an automatic healing function for the grid model. Finally, to verify the accuracy of the system, the verification and utilization results are compared with the software used.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1278-1283
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• 2007

The 30% resistant frequencies of pathogenic bacteria were identified against generally utilizing disinfectants. Among the used disinfectants, foodsef, Taego, and Iodo 175 were dictated by lower sensitivities against pathogenic bacteria, as well as higher resistant frequencies when compared with other disinfectants. The resistant frequencies against antibiotics were also dictated by 30% through MIC (minimal inhibitory concentration) and paper disc methods. Especially, the used bacteria exhibited resistances against gentamycin, kanamycin, and streptomycin, which included in all aminoglycoside group. The MBT-01108 material, which extracted and purified from a powder obtained by processing of Opunita ficus-indica var. saboten Makino trunk, did not develop or grow resistant bacteria. Interestingly, the multi-drug resistant bacteria such as MRSA, resistant Pseudomonas aeruginosa, VRE, and E. coli 0157 did not resistant against MBT-01108 material. These results suggest that MBT-01108 material uses as an anti-microbial agent.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.681-682
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• 2013

전기는 우리 주변의 에너지 형태 중에서 가장 편리하고 광범위하게 사용되고 있다. 이러한 전기는 전자제품, 전기자동차, 에너지 저장 플랜트 등 매우 많은 분야에서 저장되고 사용되고 있다. 특히 에너지 저장 용량의 확대는 휴대폰, 노트북 PC 등 휴대용 IT 기기의 성장에 결정적인 역할을 하였다. 가볍고 작으면서도 고용량의 전기 에너지 저장 장치가 없었다면, 통신이나 인터넷 그리고 오락 등 다양한 기능을 작은 휴대용 기기에 구현할 수 없었을 것이다. 그러나 시간이 흐를수록 기기의 요구 성능이 높아지고 소비자의 니즈가 더욱더 다양해지고 고도화될수록 단일 부품으로 가장 큰 부피를 차지하는 에너지 저장 장치의 용량과 디자인은 점점 중요해지고 있다. 이러한 에너지 저장 장치에서 가장 친숙한 형태는 2차 전지 계열이다. 납 축전지를 비롯하여, 니켈수소, 니켈카드뮴, electrochemical capacitor와 Li ion 계열 등이 대표적이다. 특히 Li ion 배터리는 모바일, 자동차 및 에너지 저장 그리드 등과 같은 다양한 분야에 가장 많이 적용되고있다. Li ion 배터리에 대하여 현재의 핵심적인 연구분야는 전극 재료(cathode, anode)와 electrolyte에 대한 것이다. Anode 전극 재료 중에서 가장 많이 사용되는 재료는 카본을 기반으로 하는 재료로 안정성에 대한 장점이 있지만 에너지 밀도가 낮다는 단점이 있다. 에너지 저장 용량 증가에 대한 필요성이 증가하기 때문에 현재 많이 사용되고 있는 에너지 밀도가 낮은 카본 재료를 대체하기 위해서 이론 용량이 높다고 알려진 실리콘과 같은 메탈이나 주석 산화물과 같은 천이 금속 산화물에 대하여 많은 연구가 진행되고 있다. 특히 현재까지 알려진 많은 재료 중에서 가장 큰 capacity (~4,000 mAh/g)를 가지고 있다고 알려진 실리콘이 카본의 대체 재료로 많은 연구가 진행되고 있다. 그러나, Li 과 반응을 하며 약 300~400%에 달하는 부피팽창이 발생하고, 이러한 부피 팽창 때문에 충 방전이 진행됨에 따라 current collector로부터 박리되는 현상을 보여 빠른 용량 감소를 보여주고 있다. 본 연구에서는 adhesion layer를 current collector와 실리콘 전극 재료 사이에 삽입하여 충 방전 시 부피팽창에 의한 미세구조의 변화와 electrochemical 특성에 대한 영향을 알아보았다. 실험에 사용한 anode 전극은 상용 Cu foil current collector에 RF/DC magnetron 스퍼터링을 통해 다양한 종류(Ti, Ta 등)의 adhesion layer과 200 nm 두께의 Si 박막을 증착하였다. 또한 Bio-logic Potentiostat/ Galvanostat VMP3 와 WanAtech automatic battery cycler 장비를 사용하여 0.2 C-rate로 half-cell 타입의 코인 셀로 조립한 전극에 대한 충 방전 실험을 진행하였다. Adhesion layer의 사용으로 인해 실리콘 박막과 Cu current collector 사이의 박리 현상을 줄여줄 수 있었고, 충 방전 시 Cu 원자의 실리콘 박막으로의 확산을 통한 brittle한 Cu-Si alloy 형성을 막아 줄 수 있어 큰 특성 향상을 확인할 수 있었다. 또한, 리튬과 실리콘의 반응을 통한 형태와 미세구조 변화를 SEM, TEM 등의 다양한 장비를 사용하여 확인하였고, 이를 통해 adhesion layer의 사용이 전극의 특성향상에 큰 영향을 끼쳤다는 것을 확인할 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3442-3447
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• 2014

A simple method to evaluate the hygroscopic characteristics of polymer of microelectronic plastic package is suggested. To evaluate the characteristics, specimens were prepared, and the internally absorbed moisture masses were measured as a function of the absorbing time and calculated numerically. The hygroscopic pressure ratio was calculated by heat transfer analysis supported by commercial FEM code because the hygroscopic diffusion equation has the same form as the heat transfer equation. The moisture masses were then summed by the self developed code. The nonconductive polymers had quite different characteristics for the different lots, even though they were the same products. The absorbed moisture mass variations were calculated for several different characteristics, and the optimal curve of the mass variation close to experimental data was selected, whose solubility and diffusivity were affected by the hygroscopic characteristics of the material. The method can be useful in the industrial fields to quickly characterize the polymer material of the semiconductor package because the fast correspondence is normally required in industry. The weight changes in the aluminum-nonconductive-polymer joint due to moisture absorption were measured. The deformed system was also measured using the Moire Interferometry system and compared with the results of finite element analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.664-673
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• 2018

The industrial control system (ICS) has operated as a closed network in the past, but it has recently been linked to information and communications services and has been causing damage due to cyber attacks. As a countermeasure, the Information Communication Infrastructure Protection Act was enacted, but it cannot be applied to various real control environments because there is only a one-way policy-from a control network to a business network. In addition, IEC62443 defines an industrial control system reference model as an international standard, and suggests an area security model using a firewall. However, there is a limit to linking an industrial control network, operating as a closed network, to an external network only through a firewall. In this paper, we analyze the security model and research trends of the industrial control system at home and abroad, and propose an industrial control system security model that can be applied to the actual interworking environments of various domestic industrial control networks. Also, we analyze the security of firewalls, industrial firewalls, network connection equipment, and one-way transmission systems. Through a domestic case and policy comparison, it is confirmed that security is improved. In the era of the fourth industrial revolution, the proposed security model can be applied to security management measures for various industrial control fields, such as smart factories, smart cars, and smart plants.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.78-82
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• 2015

Hollow silica particles were prepared using sodium silicate and organic templates. Polystyrene latex (PSL) particles produced by dispersion polymerization were used as organic templates. PSL particles ranged from $1{\mu}m$ to $3{\mu}m$ in diameter were synthesized by adjusting the amount of 2,2'-azobisisobutyronitrile (AIBN). The PSL/$SiO_2$ core-shell particles were prepared by coating of silica nanoparticles originated from sodium silicate using sol-gel method. The organic templates were removed by the organic solvent, tetrahydrofuran (THF). Morphology of hollow silica particles was investigated with respect to types of the reaction medium and pH during the process. By changing the solvent from ethanol to water, hollow silica particles were successfully formed. Hollow silica particles with the uniform shell thickness were produced at low pH as well. The reflectivity of the as-prepared silica particles was measured in the range of the wavelength of UV and visible light. Hollow silica particles showed much better reflective properties than the commercial light reflector, Insuladd.

• Journal of Dairy Science and Biotechnology
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• v.38 no.2
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• pp.89-98
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• 2020

The purpose of this study was to investigate the probiotic properties of lactic acid bacteria (LAB) isolated from a Korean traditional food kimchi. Gram staining was performed by Macrogen (Macrogen, Inc.) for identification of the LAB. Five strains of LAB were identified, including DKGF9 (Lactobacillus plantarum), DKGF1 (L. paracasei ), DKGF8 (L. casei ), DK207 (L. casei ), and DK211 (L. casei ). The biological activities of the isolated strains were assessed. The results showed that heat resistance of the strains was similar to or higher than the commercial strain L. acidophilus LA-5. Indirect testing of the ability of the strains to attach to the mucin layer revealed that DKGF9, DKGF1, and DKGF8 have high binding affinities for the mucous layer. All strains showed antimicrobial activity similar to or higher than the commercial strain LA-5. In proteolysis experiments, the diameters of proteolysis zones of the five strains increased in the period of 24-72 h, with DKGF1 exhibiting the largest zone diameter. Three strains were selected based on their antioxidant activities. Among the five isolated strains, L. paracasei DKGF1 showed potential probiotic activity, and thus, it may be useful for the development of health-promoting products.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.56-64
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• 2008

Although the EGSE (Electrical Ground Support Equipment) and MCS (Mission Control System) have many similar or even identical functions, the EGSE used for assembly, integration and validation phase and the MCS for the mission operations phase are normally developed separately and used by different groups of engineers. However, the common ground system for EGSE and MCS has developed and many space missions such as PROBA (PRoject for On-Board Autonomy), ROSETTA, MARS EXPRESS, CRYOSAT (Cryosphere Satellite), GOCE (Gravity field and steady state Ocean Circulation Explorer), and GALILEO have used or will use it to minimize risk, reduce cost and improve overall product quality. It is based on ECSS (European Cooperation for Space Standards) E70 which is the international standard for ground systems and operations published by ECSS E70 Working Group. The ECSS E70 contains the basic rules, principles and requirements applied to the engineering of the ground systems and the execution of mission operations. This paper introduces standardization policy, organization and standard documentation in ECSS. The overview of ECSS E70 such as status, purpose and contents is also described in this paper.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.744-753
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• 2015

This paper presents the results of research on developing marine unified communications to provide VoIP service based on marine satellites. With the recent popularity of smart-phones and other mobile devices, the demand for Internet-based wired and wireless unified technology has been growing in marine environments, and increasing interest is being directed to VoIP products and service models with high price competitiveness and the ability to deliver a variety of services. In this regard, this research designed three instruments, developed their unit modules, and verified their performances. These three instruments included the following: (1) a marine VoIP module equipped with an analogue gateway that can be linked to the existing devices used in vessels, which is more than 80% smaller than that of a land system; (2) a text/voice/video engine for marine satellite communications that runs on technology that minimizes communication data usage, which is a core technology for a marine VoIP service; and (3) a unified communication service that can support multilateral cloud-based message conversations, telephone number-based call functions, and voice/video calling between a private space in a ship and shore.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1094-1103
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• 2012

Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This technology is a software which is to provide the core technology which was suggested by the United state's military M&S standard framework. Simulator, virtual simulation, and inter-connection between military weapons system S/W which executes on network which is M&S's core base technology, and it is a technology which also can be used for various inter-connection between S/W such as game and on-line phone. These days although RTI is used in military war game or tactical training unit field, there is none in Korea. Also, it is used in mobile-game, distribution game, net management, robot field, and other civilian field, but the number of examples are so small and informalized. Through this developing project, we developed the core technique and RTI software and provided performance of COTS level to improve communication algorithms.