• 산업공학
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• 제17권2호
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• pp.142-148
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• 2004

The objective of bridge construction cost allocation is to distribute in a fair and rational manner the bridge construction costs among those vehicles using the bridge. In most bridge construction cost allocation studies, bridge construction costs are mainly distributed according to traffic load(gross vehicle weight), without any consideration of bridge capacity requirements(the number of lanes). In this paper, a bridge cost allocation method for considering both traffic capacity and traffic loads is developed. The proposed method is based on cooperative game theory, particularly two concepts known as the Aumann-Shapley (A-S) value and Shapley value. This method can help to analyze the impact of traffic capacity costs. By applying the proposed method to an example, traffic capacity cost is found to be high so that traffic capacity should be considered to allocate the bridge construction costs to vehicle classes in a more equitable manner.

• 산업공학
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• 제12권3호
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• pp.362-373
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• 1999

Resource Constrained Dynamic Multi-Projects Scheduling (RCDMPS) is intended to schedule activities of two or more projects sequentially arriving at die shop under restricted resources. The aim of this paper is to develop a new problem solving method for RCDMPS to make an effect schedule based by constraint programming. The constraint-based scheduling method employs ILOG Solver which is C++ constraint reasoning library for solving complex resource management problems and ILOG Schedule which is a add-on library to ILOG Solver dedicated to solving scheduling problems. And this method interfaces with ILOG Views so that the result of scheduling displays with Gantt chart. The scheduling method suggested in this paper was applied to a company scheduling problem and compared with the other heuristic methods, and then it shows that the new scheduling system has more preference.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2702-2704
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• 2005

This paper proposes the genetic algorithm (GA)-based fuzzy modeling method for intelligent tracking of a maneuvering target. When the maneuvering to turn or taking evasive action, the performance of the standard Kalman filter has been degraded because residual between the modeled target dynamics and the actual target dynamics. To solve this problem, the state prediction error is minimized by the intelligent estimation method. Then, this filter is corrected by measurement corrections which is the fuzzy system. The performance of the proposed method is compared with those of the input estimation(IE) technique through computer simulation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.95-98
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• 1999

In this study, a method to find the optimal intermediate die geometry for the multi-stage drawing process for the rectangular rod from a round bar is proposed and a program using the proposed method is developed. On the stage of the design of the intermediate die geometry, the virtual die was constructed using the initial billet as a inlet of the drawing die and the final product as a exit of that and the virtual die was divided by the number of pass. Divided die was transformed into the rectangular one which is the intermediate die geometry for the multi-stage rectangular drawing process. In order to verify the application of the proposed method on the real industrial product, the drawing of the rectangular rod from a round which composed two stage has been performed and simulated by the three dimensional rigid plastic finite element method.

• 산업공학
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• 제14권1호
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• pp.79-83
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• 2001

In this paper, we propose a simple method to reduce categorical variables into smaller, but significant numbers, and also demonstrate how the proposed method can be applied to the problem of reduction that empirical research often faces in the course of data processing. For the purpose, we introduce a concept of pseudo-correlation coefficient to make it possible to use factor analysis (FA) as a tool for reducing variables. The main idea of the concept is to deal with the measures of association of categorical variables in the sense of the concept of Pearson's correlation coefficient in order to meet the input requirement of FA. Upon examination of existing measures that could play as pseudo-correlation coefficients, Cramer's V coefficient is selected for the best result among them. To show the detailed procedure of the proposed method, a specific demonstration with the data from 329 R&D projects conducted in 18 private laboratories in electric and electronics industry is presented.

• 공업화학
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• 제22권4호
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• pp.367-375
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• 2011

숙신산 에스테르 유도체는 방청성능 및 윤활성능이 우수하여 금속가공유 및 유압작동유 등의 첨가제로 많이 사용되고 있다. 본 연구에서는 광유계 윤활기유의 방청제로 사용하기 위하여 알킬 무수 숙신산과 여러 가지 지방 알콜과의 개환반응을 행하여 카르복실 그룹과 에스테르 그룹을 동시에 함유하는 숙신산 알킬 하프-에스테르 유도체를 97% 이상의 수율로 합성하였으며 1 중량% 농도범위에서 광유계 오일에 잘 용해되었다. 합성 유도체는 $^1H-NMR$ 및 FT-IR 스펙트럼으로 구조를 확인하였으며, GC 분석을 통하여 화합물의 순도를 확인하였다. 또한, 합성 유도체의 해수에 대한 방청성능을 ASTM D665 표준방법과 무게 중량법으로 평가하여 카르복실산 그룹을 함유하지 않는 숙신산 알킬 에스테르 유도체와 비교하였다. 방청성능 평가 결과, 합성 유도체의 농도가 증가하고 분자 내에 포함된 알킬기의 사슬이 짧을수록 상대적으로 방청성능이 우수하였으며 비교물질인 숙신산 알킬 에스테르 유도체는 방청성능을 전혀 나타내지 않았다. 무게 중량법으로 평가한 80 중량ppm 농도를 첨가한 오일의 방청효율 % (IE%)는 알킬기의 사슬이 짧을수록 높은 값을 나타내어 최고 95% 이상이었다. 또한, 발청속도(Corrosion rate, CR)는 알킬기의 사슬이 짧을수록 낮은 값을 나타내어 80 중량ppm에서 최고 0.3 mm/year 이하를 나타내었다. 즉, 숙신산 알킬 하프-에스테르 유도체의 해수에 대한 방청성능은 분자 내에 함유되어 있는 카르복실산 그룹으로 인하여 나타나는 것으로 판단되었다.

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.19-34
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• 2015

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck.

• 한국전기전자재료학회논문지
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• 제17권10호
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• pp.1100-1106
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• 2004

In this paper, we intend to make fringe-field switching (FFS) mode cell by the ion beam (IB) alignment method on the a-C：H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for fringe-field switching (FFS) cell and the aligning capabilities of nematic liquid crystal (NLC) using the alignment material of a-C：H thin film as working gas at 30 W rf bias condition. A high pretilt angle of about 5 $^{\circ}C$ by ion beam (IB) exposure on the a-C：H thin film surface was measured. Consequently, the high pretilt angle and the good thermal stability of LC alignment by the IB alignment method on the a-C：H thin film surface as working gas at 30 W rf bias condition can be achieved. An excellent voltage-transmittance (V -T) and response time curve of the IE-aligned FFS-LCD was observed with oblique IB exposure on the a-C：H thin films. Also, AC V-T hysteresis characteristics of the IB-aligned FFS-LCD with IE exposure on the a-C：H thin films is almost the same as that of the rubbing-aligned FFS cell on a polyimide (PI) surface.

• 한국전산구조공학회논문집
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• 제27권6호
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• pp.493-500
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• 2014

본 연구에서는 농업시설물 중 내재해형 비닐하우스와 축사에 대한 화산재 취약도를 평가하였다. 이들 농업시설물에 대한 화산재 취약도를 평가하기 위해 화산재 하중의 확률밀도함수와 대상 시설물 저항성능의 확률밀도함수를 비교하는 해석적 접근법 기반의 FOSM(first-order second-moment) 방법이 이용되었다. 화산재 취약도 평가를 위하여 폭과 높이 그리고 단면 및 재료적 특성이 상이한 6종의 내재해형 비닐하우스와 표준형, 해안형, 산간형으로 구분된 3종의 축사가 사용되었다. 또한 FOSM 방법으로 평가된 내재해형 비닐하우스와 축사의 취약도는 GEV(generalized extreme value) 분포함수의 모수 형태로 최적화된 후 데이터베이스화되었다. 본 연구에서 평가한 화산재 취약도는 백두산 화산분화에 따른 화산재 퇴적에 대한 농업시설물의 위험도 평가를 위하여 활용될 수 있다.

• 한국전자파학회논문지
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• 제12권1호
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• pp.143-152
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• 2001

본 노문에서는 S밴드 (1.5 3.9 GHz)에서 주로 사용되어지는 마이크로스트립 패치 안테나에서 복사특성의 성능저하를 방지함과 동시에 소형화방법이 연구되었다. 연구는 마이크로스트립 단일 패치 안테나에서 패치의 중앙 부분을 제거함으로써 정사각형 링(Square-ring) 형태를 가지는 마이크로스트립 안테나의 형태에 관하여 수치적인 방법으로 수행되었다. 또한 링 구조를 가지는 정사각형 마이크로스트립 안테나를 연구함에 있어서 안테나 임피던스, 공진주파수, 대역폭 등을 제어하기 위한 부수적인 파라미터들이 연구되었다. 단일 정사각형 링 마이크로스트립안테나에 있어서 패치의 중앙부분이 제거됨에 따라 입력 임피던스가 증가되고, 공진주파수와 대역폭이 감소되는 현상이 관찰되었고, 안테나의 Directivity 에는 적게 영향을 미치는 것으로 나타났다. 또한 Moment Method 방식의 Zeland 사이의 IE3D 소프트웨어를 이용하여 안테나와 전송선로간의 임피던스 정합과 대역폭의 증가를 위해 다른 개체의 정사각형의 단일 패치와 링 형태의 패치가 각각 쌓아 올려지는 적층(stacked) 구조 형태로 설계, 최적치를 도출하여 단일 패치의 마이크로스트립 안테나보다 향상된 대역폭과 이득을 얻을 수 있음이 연구되었다. 또한 수치적인 시뮬레이션 결과와 실제의 측정을 수행한 결과를 서로 비교함으로써 잘 일치함을 증명하였다.