• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2483-2485
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• 2003

As design a network system that should command and response to do tasks by PLC, to make factory automation for being distributed facilities which are not guaranteed procedure, through polling method, commands are send orderly by PLC and responses are answered by each sub-unit. It make a guarantee of sequence and drive a master-slave operation in network. This method help to distribute procedure systems and make possible dividing tasks to each unit. To make this method, network protocol's format have Master or Slave ID and tasking data and Master's command or Slave unit's report. In network interpret algorithm, skip algorithm are included and it make guarantee of protecting data though network are in noise. Data that are made by this method are send to PC to transmit long-distance user by internet.

• 도시과학
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• 제7권2호
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• pp.47-52
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• 2018

The purpose of this study is to review and evaluate the proper planning for 2030 Incheon Urban Parks & Green Space Master Plan. Some of the plans are aimed at multiple small districts within the city's old town, as local governments are planned to be sub-subsidized by Incheon Metropolitan City. However, these plans have become simple plans for each district and therefore find it difficult to collect from the perspective of the using system of the residents who are directly used. First, the construction of the urban park and green space network requires the construction of a service using system that can be felt by the users. Second, the basic idea of each district planned as the detailed strategy of the master plan should be planned through consultation with nearby the district. Third, specific targets and directions for the urban park and green space plan through the urban development project are needed.

• 도시과학
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• 제7권2호
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• pp.37-46
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• 2018

The purpose of this study is to review and evaluate the proper planning for 2030 Incheon Urban Parks & Green Space Master Plan. Some of the plans are aimed at multiple small districts within the city's old town, as local governments are planned to be sub-subsidized by Incheon Metropolitan City. However, these plans have become simple plans for each district and therefore find it difficult to collect from the perspective of the using system of the residents who are directly used. First, the construction of the urban park and green space network requires the construction of a service using system that can be felt by the users. Second, the basic idea of each district planned as the detailed strategy of the master plan should be planned through consultation with nearby the district. Third, specific targets and directions for the urban park and green space plan through the urban development project are needed.

• 수산해양기술연구
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• 제29권4호
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• pp.247-259
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• 1993

The fishing experiment was carried out by the training ship Saebada in order to analyse the mesh selectivity for trawl cod-end, in the Southern Korea Sea and the East China Sea from June. 1991 through August, 1992. The trawl cod-end used in this experiment has the trouser type of cod-end with cover net. and the mesh selectivity was examined for the five kinds of the opening of mesh in its cod-end part. A total of 163 hauls, of which having mesh size 51.2mm ; A 89, 70.2mm ; B 54, 77.6mm ; C 55, 88.0mm ; D 52 and 111.3mm ; E 20 were used respectively. Selection curves and selection parameters were calculated by using a logistic function, S=1/(1+exp super(-(aL+b)) ). The mesh election master curves were estimated by S=1/(1+exp super(-[a(L/M)+$\beta$]) ). and the optimum mesh size were calculated with (L/M) sub(50) of master curve. In these cases 'a' and '$\alpha$' are slope, 'b' and '$\beta$' are intercept. 'L' is body length of the target species of fishes, 'M' is the mesh size, and 'S' denotes mesh selectivity. In this report, the four species of compressed form fishes were taken analized according to fish shape, and 'S' denotes mesh selectivity. In this report, the four species of compressed form fishes were taken analized according to fish shape, and the results obtained are summarized as follows: 1. Red seabream Pagrus major(Temminct et Schlegel) and yellow porgy Dentex tumifrons(Temminct et Schlegel) ; Selection rate in each mesh size of A, B, C, D and E were 99.7%, 97.5%, 91.4%, 76.7% and 57.8% respectively. Selection parameters 'a' and 'b' of mesh sizes C, D and E were 2.65 and -28.62, 4.40 and -77.73, 2.31 and -46.99, and their selection factors were 1.39, 2.10, 1.83 respectively. Selection parameters of master curve '$\alpha$' and '$\beta$' were 3.05 and -5.65 respectively, and (L/M) sub(50) was 1.85. The optimum mesh size of Red seabream was 141mm. 2. Filefish Thamnaconus modestus (Gunther) ; Selection rate in each mesh size of A, B, C, D and E were 99.6%, 98.3%, 91.2%, 80.0% and 48.6% respectively. Selection parameters 'a' and 'b' of mesh sizes C, D and E were 5.82 and -55.10, 2.92 and -36.90, 3.91 and -63.09, and their selection factors were 1.35, 1.44, 1.45 respectively. Selection parameters of master curve '$\alpha$' and '$\beta$' were 3.02 and -4.32 respectively, and (L/M) sub(50) was 1.43. The optimum mesh size was 129mm. 3. Target dory Zeus faber Valenciennes ; Selection rate in each mesh size of A, B, C, D and E were 99.7%, 100%, 83.2%, 91.6% and 65.0% respectively. Selection parameters 'a' and 'b' of mesh sizes C, D and E were 3.85 and -32.46, 4.19 and -57.38, 2.45 and -40.03, and their selection factors were 1.09, 1.56, 1.47 respectively. Selection parameters of master curve '$\alpha$' and '$\beta$' were 2.64 and -3.53 respectively, and (L/M) sub(50) was 1.34. The optimum mesh size was 127mm. 4. Butterfish Psenopsis anomala (Temminct et Schlegel) ; Selection rate in each mesh size of A, B, C, D and E were 99.2%, 34.1%, 46.5%, 14.3% and 2.4% respectively. Selection parameters 'a' and 'b' of mesh sizes B, C and D were 5.35 and -71.70, 5.07 and -69.25, 3.31 and -62.06 and their selection factors were 1.91, 1.75, 2.13 respectively. Selection parameters of master curve '$\alpha$' and '$\beta$' were 3.16 and -6.24 respectively, and (L/M) sub(50) was 1.98. The optimum mesh size was 71mm.

• Tribology and Lubricants
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• 제37권5호
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• pp.179-188
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• 2021

Reputed for their low friction coefficient and wear protection effect, diamond-like carbon (DLC) materials are considered amongst the most important lubricant coatings for tribological applications. In this framework, this investigation aims to elucidate the effect of a few operating parameters, such as applied stress and sliding amplitude on the friction lifetime of DLC coatings. Fretting wear tests are conducted using a 12.7 mm radius counterpart of 52100 steel balls slid against a substrate of the same material coated with a 2 ㎛ thickness DLC. Approximately, 5 to 57 N force is applied, generating a maximum Hertzian contact pressure of 430 to 662 MPa, corresponding to the applied force. The coefficient of friction (CoF) generates three regimes, first a running-in period regime, followed by a steady-state evolution regime, and finally a progressive increase of the CoF reaching the steel CoF value, as an indicator of reaching the substrate. To track the wear scenario, interrupted tests are performed with analysis combining scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), 3D profilometer and micro-Raman spectroscopy. The results show two endurance values: one characterizing the coating failure (Nc₁), and the other (Nc₂) indicating the friction failure which is situated where the CoF reaches a threshold value of μ_th = 0.3 in the third regime. The Archard energy density factor is used to determine the two endurance values (Nc₁, Nc₂). Based on this approach, a master curve is established delimitating both the coating and the friction endurances.

• 접착 및 계면
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• 제23권4호
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• pp.116-121
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• 2022

Organic field-effect transistor가 실제 전자 장치에 쓰이기 위해서는 유기반도체 용액공정용 미세 패터닝 기술이 요구된다. 본 연구에서는 기존의 스핀 코팅 방법보다 미세 패턴을 형성할 수 있는 소프트 리소그래피 방법이 더 우수한 전기적 특성을 가질 수 있다는 것을 확인하기 위해 비교 분석하였다. Compact Disc 표면의 나노 패턴을 이용하여 유연한 마스터 몰드를 제작하였고, 650 nm 폭의 2,7-Dioctyl [1] benzothieno [3,2-b] [1] benzo thiophene (C_8-BTBT) 나노 와이어를 얻었다. 그 결과 소프트 리소그래피 방법을 이용해 제작된 소자 이동도는 0.086 cm²/Vs이며, 스핀 코팅으로 만들어진 소자 이동도는 0.0036 cm²/Vs으로 소프트 리소그래피 방법으로 제작된 소자가 약 20배 이상 높은 이동도와 더 우수한 전기적 성능을 보였다.

• 정보보호학회논문지
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• 제22권3호
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• pp.427-438
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• 2012

SCADA(Supervisory Control and Data Acquisition) 시스템은 국가의 중요한 기반 망인 전력, 가스, 상하수도 등을 제어하기 위해 사용된다. 이전의 폐쇄적인 통신 환경과 달리 최근 개방 통신 환경을 사용함에 따라 안전한 통신을 위한 키 관리 기술이 연구되고 있다. 본 논문에서는 SCADA 시스템을 구성하는 MTU(Master Terminal Unit), Sub-MTU, RTU(Remote Terminal Unit)에 각각 페어링을 이용한 ID 기반의 키 관리 방안을 제시한다. 또한, 예상치 못한 사고나 악의적인 공격들로 인하여 장치들의 개인 키가 노출되거나 또는 KMS(Key Management System)의 마스터 키가 노출되었을 경우에도 SCADA의 키 관리 시스템을 복구할 수 있는 방법을 제시한다.

• 한국산학기술학회논문지
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• 제13권7호
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• pp.2955-2963
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• 2012

본 논문은 다품종 동적 로트사이징 문제를 풀기 위하여 열생성 기법에 기반한 알고리즘을 제안한다. 제안한 알고리즘의 기본 개념은 한정된 생산 용량을 주문제를 통하여 n개의 제품에 할당하고, 주문제에 의하여 할당된 생산용량을 기반으로 하여 각각의 제품에 대하여 최적화된 로트사이징 문제를 반복적으로 풀어나감으로써 해를 구해나가는 것이다. 부문제를 풀기 위해 본 논문은 로트사이즈, 재공재고 그리고 생산량 간에 존재하는 비선형관계를 기반으로 한 M/G/1모델 기반의 최적화 로트사이징 모델을 제안한다. 실험을 통하여 제안한 알고리즘이 비교적 짧은 시간안에 좋은 해를 생성함을 보여준다.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1778-1782
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• 2017

The interaction of $NpO^+_2$ with $Cl^-$ was studied using visible-near-infrared spectroscopy in $NaCl-Ca-Cl_2-NaClO_4$, $NaCl-NaClO_4$, and $CaCl_2-NaClO_4$ solutions with ionic strength (I) of 6M. The spectra of $NpO^+_2$ around 980 nm varied with $Cl^-$ concentration in the $NaCl-CaCl_2-NaClO_4$ and $NaCl-NaClO_4$ solutions at [$Cl^-$] ${\geq}3.5M$, but not in the $CaCl_2-NaClO_4$ solution. Assuming the 1:1 interaction between $NpO^+_2$ and $Cl^-$, the apparent equilibrium constants at I = 6M were evaluated. The presence of $Ca^{2+}$ was found to destabilize overall interaction between $NpO^+_2$ and $Cl^-$. The observations were consistent with the density functional theory calculation.

• 설비공학논문집
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• 제9권2호
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• pp.163-170
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• 1997

Solubility on $(LiBr+CaCl_2)$ in water has been measured systematically and compared with those of pure LiBr. It has been observed that there exists optimum value of $CaCl_2(LiBr+CaCl_2)$ in solubility when total$(LiBr+CaCl_2)$ concentration is higher than 57wt%. As total concentration increases up to 65wt%, it is found that the optimum value also increases monotonically. From the experimental results, a master plot has been constructed, with which optimum ratio of LiBr to $CaCl_2$ can be found in terms of total concentration. Vapor pressure of $H_2O/(LiBr+CaCl_2)$ solution with optimum contents of $CaCl_2$ has been observed to be changed negligibly at relatiely low temperature. However, as temperature increases, it is found that increasement in vapor pressure is significant.