• 시큐리티연구
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• 제5호
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• pp.211-241
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• 2002

Koreans are the most avid Internet surfers in the world according to Nielson/NetRatings(Reuters, August 2001) and most Internet connections are made through high-speed connections like Digital Subscriber Lines (DSLs). The result of such internet fervor is a nation that is fertile in both hackers and software companies(over 200 in the field of network security alone). However, by-product of Internet activity is cyber crime and the need to protect innocent users from the dangers of cyber criminals and cyber-terrorists be they are individuals or organized groups. Hence the Cyber Terror Response Team (CTRT) was organized in late 2000 with the mandate to fulfill that role. In these contexts, this study analyzes the actual conditions of cyber terror and suggests the countermeasures against cyber terror in Korea.

• 드라이브 ㆍ 컨트롤
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• 제12권2호
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• pp.34-38
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• 2015

Research and development of mineral resource related products has progressed with the increased need to develop mineral resources. The DTH hammer is one a resultant product. However, due to particular work conditions of underground drilling, it is difficult to obtain direct data on the DTH Hammer. A DTH drill rig requires a lot of money and time for actual testing. This thesis aimed to resolve this problem by using CAE. First, the structure of the DTH hammer and the movement was analyzed. Next, a standard model based on simulation was proposed and then experimentation and comparison verification was conducted. In addition, the verified models were applied to products of various sizes, and the models used in simulation were compared by conducting field tests.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.131-142
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• 2001

A wrinkling is the instability phenomenon influenced by material properties, shape geometry, forming conditions, stress state, etc. The wrinkling is considered as a critical defect in appearance of product. Many wrinkling prediction methods using thickness strain distribution and farming analysis have been proposed. The wrinkling, however, is not easily predicted precisely by these methods. In this study, the region in the biaxial plane stress state is modeled with a rectangular plate introducing the effective dimension, and critical stress values for the wrinkling are calculated. Prediction index for the wrinkling is then evaluated by normalizing the actual stress with respect to the critical stress. In order to show the validity and efficiency of the method proposed, the wrinkling prediction for a squared sheet in the uniaxial tensile stress and auto-body front finder panel is performed.

• Elastomers and Composites
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• 제52권4호
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• pp.309-316
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• 2017

In injection molding, the quality of an injection molded product varies greatly depending on the molding conditions. Many researche studies have been conducted on the quality analysis of molded parts according to the molding conditions such as injection pressure, injection temperature, and packing pressure. However, there have not been many studies on the V/P switchover timing. It is known that when a large pressure is applied to a cavity in the packing phase, the cavity pressure is most affected by the packing pressure. In addition, depending on the position (timing) of the packing pressure, it can have a direct influence on quality based on the shrinkage and dimensions of the molded parts. In this study, the change in pressure profile in the cavity according to the V/P switchover position is confirmed. A CAE analysis program (Moldflow) was used to simulate and analyze two models using the PC and PBT materials. In order to compare these results with the actual injection molding results, injection molding was performed for each V/P switchover position, and the correlation between simulation and experiment, especially for the shrinkage of molded parts, was evaluated.

• 한국안전학회지
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• 제32권5호
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• pp.1-7
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• 2017

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses is equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. In this study, the bursting test for the pressure vessel depending on the heat treatment conditions of the vessel in which the actual ruptured accident occurred, after the bursting test, the fracture pattern analysis had performed. The mechanical materials properties test using Instrumented Indentation Test had performed to confirm the mechanical properties for each heat treatment cases. Also, the fractography analysis and metallographic analysis had performed to find out the difference of each heat treatment case. By comparing normal vessel with abnormal vessel which have defect of heat treatment conditions in term of the bursting patterns and characteristics of containers using various forensic engineering methods, especially, it is possible to understand how important the heat treatment process is in the high pressure vessel unlike any product.

• 한국분무공학회지
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• 제29권2호
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• pp.53-59
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• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• Design & Manufacturing
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• 제12권2호
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• pp.27-33
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• 2018

Korea's automobile industry, which has grown rapidly to become the world's fifth-largest automobile producer, To cope with environmental pollution and energy problems in order to prevail competitive edge in global market We are investing a lot of research personnel and costs. Among them, for realizing alternative light weight It is a part of the automobile module system that has achieved the technological development before the breakthrough in the injection molding process in the press process. Door module PNL was the subject of research. The door module PNL is expected to cause warpage before the mold production due to the thin and flat product characteristics and fiber orientation characteristic of the material. In this paper, CAE analysis and reverse correction tool Design. CAE analysis to obtain the results of weld line position, bending position and deformation value Through the correction tool, think3, the original product was modified before the mold production to improve the completeness of the parts. In fiber orientation, the position and size of the cooling channel in the mold, the position and size of the gate, Temperature, pressure, time, and work environment. Compared with the result of CAE analysis, the product that was reverse-corrected by Think3 was manufactured, and injection molding was performed. Injection molding products were tested 24 hours later. 3.5 mm to 7.0 mm, and under the fixed condition, the deviation was from 1.1 mm to 1.5 mm. Unlike the CAE analysis, the deviation of the actual injection pressure and the cooling temperature, the fiber orientation of the material, In order to solve this problem, it is necessary to compare the injection conditions with the database, I knew I had to catch the standard.

• 한국식품저장유통학회지
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• 제18권5호
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• pp.721-728
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• 2011

Camellia oil과 palmitic, 그리고 stearic ethyl ester를 기질로 하고 Lipozyme TLIM을 촉매로 이용하여 interesterification을 통한 POS를 많이 함유한 반응물을 합성하고자 하였다. 반응 조건(반응효소비율, 반응시간, 기질의 비율)을 독립변수로 하여 중심 합성 계획에 의한 반응 표면 분석을 통하여 POS의 함량은 높이고, sn-2 position의 acyl migration을 낮추어 합성하는 최적화 조건을 얻었다. POS를 많이 함유한 반응물의 합성 최적화 조건은 반응 효소양($X_1$)= 5.9%, 반응시간($X_2$)= 60 min, 그리고 기질비율($X_3$)= 1:3(1 mole의 camellia oil: 3 mole의 palmitic ethyl ester + 3 mole의 stearic ethyl ester)이었다. 이와 같은 조건으로 획득된 실재 효소반응 합성물의 TAG-P/O/S(palmitic, stearic과 oleic 지방산을 각각 1 분자씩 어느 위치이던지 함유한 TAG, 즉 POS 및 PSO/OSP/OPS/SPO)의 합성율($Y_1$)은 20.19%이었고, 이때 acyl migration 등에 의하여 sn-2 위치에 결합(이동)한 palmitic과 stearic acid의 양(P/S-sn-2)인 $Y_2$는 12.71% 이었다.

• 디자인학연구
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• 제16권2호
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• pp.233-242
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• 2003

포장의 중요성이 점차 크게 부각되면서 포장의 본질이 무엇인가를 인식하고 사회 환경에 대응하는 적절한 포장이 무엇인가를 생각할 필요가 있다. 특히 오늘날 자연 및 에너지의 소비 에 대한 관심이 높아 가면서, 생활폐기물 전체 중량의 32%, 용적으로 50%를 차지하고 있다는 포장폐기물이 공해와 대기오염 등 환경에 미치는 영향에 있어서 심각한 문제점의 하나로 인식되기도 한다. 본 논문에서는 전체 포장폐기물에서 60%의 비율을 차지하는 지류포장재가 적정포장의 개념을 바탕으로 현재 우리나라 포장의 실태를 분석하여 문제점과 해결방안을 모색해 본다. 본 연구에서는 우리나라 제과업체 중 가장 대표적인 4개 기업의 제품 8$\ulcorner$종을 중심으로 각각의 수집된 샘플들의 지기 포장용적과 내용물의 용적, 그리고 내용물 용적을 제외한 공간의 용적을 측정하여 비교, 분석하였다. 이와 같이 적정포장 실태를 분석한 결과, 포장용적에 대하여 내용물을 제외한 평균 공간 용적률은 60.46%에 이른다. 과자류의 경우 우리나라에서는 제품대비 포장 공간 비율을 20%로 제한하고 있다는 것을 볼때, 포장의 공간용적비가 지나치게 높다는 것을 알 수 있다. 앞으로 우리는 이러한 문제점을 인식하고 적절한 포장 즉, 포장의 적정화에 의한 폐기물의 감량화, 폐기물의 재자원화, 포장재와 완충재의 사용을 합리화하는 환경을 배려한 포장디자인을 개발하는데 관심을 두어야 할 것이다.

• 상하수도학회지
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• 제32권1호
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• pp.1-10
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• 2018

Recently, interest in the development of alternative water resources has been increasing rapidly due to environmental pollution and depletion of water resources. In particular, seawater desalination has been attracting the most attention as alternative water resources. As seawater desalination consumes a large amount of energy due to high operating pressure, many researches have been conducted to improve energy efficiency such as energy recovery device (ERD). Consequently, this study aims to compare the energy efficiency of RO process according to ERD of isobaric type which is applied in scientific control pilot plant process of each $100m^3/day$ scale based on actual RO product water. As a result, it was confirmed that efficiency, mixing rate, and permeate conductivity were different depending on the size of the apparatus even though the same principle of the ERD was applied. It is believed that this is caused by the difference in cross-sectional area of the contacted portion for pressure transfer inside the ERD. Therefore, further study is needed to confirm the optimum conditions what is applicable to the actual process considering the correlation with other factors as well as the factors obtained from the previous experiments.