계류돌핀의 강관말뚝식 하부구조에 대한 실용적 설계최적화 과정을 제시하고, 수치 예를 통하여 유용성을 평가하였다. 유한차원 최적설계 문제의 정식화에서, 말뚝들을 몇 개의 그룹으로 구분하여 이들의 기하학적 위상과 단면의 치수를 설계변수로 활용하였다. 설계목적함수는 말뚝의 총 중량이며, 설계제약조건은 응력과 근입 깊이, 설계변수의 상한과 하한 등이다. 설계변수의 연계와 고정을 통해 몇 가지의 실용적 설계 대안을 검토하였다. 최적화 프로그램으로는, 순차2차계획법(SQP)을 사용하고 또 쉽게 얻을 수 있는 PLBA 및 IMSL 라이브러리의 DNCONF서브루틴을 이용하였다. 수치예제의 돌핀은 20개의 강관말뚝으로 하부구조를 형성하며, 이중 4개는 연직말뚝이고 16개는 경사말뚝이다. 다양한 대안 설계에서 성공적으로 최적해를 얻었으며, 실용적인 최적 설계과정 임을 확인할 수 있었다.

다분야 통합 시스템의 설계문제는 다량의 설계변수와 구속조건으로 구성되며 다수의 공학적 현상으로 연관되어 있다. 다분야 통합 최적설계 문제를 효과적으로 다루기 위해서는 다양한 해석분야의 공학적 설계원리를 동시에 고려하여 균형 있고 유기적인 방법으로 최적의 설계를 결정하는 체계적인 설계자동화기술이 요구된다. 다분야 통합 설계문제를 위한 효율적인 설계방법론으로 분리기반 최적화 기법이 적용되는데 이 방법은 한 단위의 대규모 설계문제를 여러 개의 하부시스템으로 분리하여 독립적으로 최적화를 수행하고 각 하부 시스템으로부터의 설계해 사이의 중재 및 통합화를 거쳐 최종적으로 수렴된 최적설계를 찾는 방법이다. 본 논문에서는 분리기반 최적화기법을 다분야 통합최적 설계문제에 적용하는데 필요한 시스템분리기법을 유전알고리즘 및 다층 역전 파 신경회로망을 이용하여 정립하였다. 시스템분리기법을 검증하기 위해 최근 미국 Boeing사에서 개발중인 고속 민간항공기인 HSCT의 시뮬레이션기반 설계문제를 이용하였다. 대규모 설계시스템의 분리결과는 전체 설계문제의 특성을 파악하기 위한 자료로 활용되며 향후, 분리기반 최적화과정에서 최종적으로 통합된 최적설계를 탐색하는데 필요한 기반구조를 제공한다.

fishing boat is a specialized vessel which is intended to perform certain well defined tasks. Its size, deck-layout, carrying capacity and equipment are all related to its function in carrying out its planned operations. Therefore the process of fishing boat design is inherently combined with optimization of the design variables called the economic optimization criteria. Optimization then is a process in which minimum value of weight or cost is established through evaluation of consecutive designs in which one or more design parameters are varied. This paper is to study the basic-design of Stow-net fishing vessel in the Mok-Po region. The main task is developed the preliminary design model of engineering economic system in order to use optimization techniques from operation research the design problem needs to be expressed in terms of objective function and numerous constrains like : speed, fish hold capacity, fishing range, displacement and weight, ratio of main dimensions, etc. The objective function represents the criterion which is NPV such as the ratio of revene/cost. When using computers of limited capacity like P/C, the developed basic-design model of the economic optimization procedure must be simplified to V, Cb, L/B, Dv, Db and less than 15 constraint equations. The main conclusions of this study have attempted to show that economic considerations are essential in Stow-net fishing vessel basic design and operations, and that techno-economic evaluation is an important tool for the design of Stow-net fishing vessel in 69ton and 79ton.

전미분 개념과 보조변수식을 사용하여 한 평면상에 투영할 수 없는 일반 형상의 축대칭 쉘 구조물에 대한 형상 설계민감도 해석방법을 개발하였다. 이 방법의 기본 개념은 대상 구조물을 여러 구간으로 나눈후, 각 구간마다에 얕은 아치나 축대칭 쉘에 사용되는 설계민감도 식을 적용하는 것이다. 그러나 기존의 설계민감도식은 투영면에 수직한 방향의 변분에 관한 것이기 때문에 각 구간 사이의 연속성을 유지하기가 곤란하므로, 이식을 확장하여 곡면의 법선 방향 변분에 관한 민감도 식을 유도하였다. 또한 개발된 방법을 원자력발전소 부품의 최적설계 문제에 적용하여 봄으로써 그 타당성과 유용성을 보였다.

This research provides optimization techniques for concrete mixture design for chloride penetration performance and cost. For optimization, objective functions are constructed with variables representing factors used in concrete mixture design process. Multi Objective Harmony Search Algorithm (MOHSA) is used for optimization and the result gives relationship between concrete’s chloride ion diffusivity and cost.

D-optimal experimental design was employed to model the effect of mixing factors on several performances of 60MPa high strength self compacting concrete and to numerically calculate the optimal mix proportion considering multi-objective characterizing the four performances like compressive strength, passing ability, segregation resistance and manufacturing cost depending on the factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content, the experiments were made at the total 32 experimental points which reduced comparing with standard experimental design.

Recently, fiber-reinforced concrete has been commonly applied to floor slabs. Therefore, this study introduces a program that can determine an optimum content of fibers incorporated in concrete accounting for the flexural and punching shear capacities, as well as serviceability conditions in the design of fiber-reinforced concrete floor slabs.

A design methodology for parametric design optimization of washing machine door is presented. We develop a motion simulator and a robotic door to simulate the various motion of washing machine doors. The motion of the washing machine door is related to hinge parameters. Springs and dampers are usually used in the hinge of washing machine door for controlling motion of the door. A physical simulator of the door motion is used for finding candidate parameters of the hinge and a robotic door whose motion is controlled algorithmically is used for consumer tests. Through the consumer evaluation on the robotic motion, the optimized parameters are determined. We find the optimal parameters as a function of angle and angular velocity of the door.

The goal of this study is to investigate the effectiveness of the use of multi constructional material in unit module plate of steel grid structure and provide engineers and designers an appropriate view point of multi-material topology optimization when making decision and information in design. The material distribution is implemented with the use of 3 materials in a given plate under prescribed loading and boundary conditions. Topology changes through automatic distribution of multi materials are presented during optimization procedures showing that there could be selective structural design possibility when using multi materials. The cross sections, stiffness and cost of material combination are useful information for engineers and designers in making design decision.

The goal of this study is to evaluate the effectiveness of using more than one material for unit element flange of Archigird. The flange is optimized using the solution of multi-material topology optimization. In this topic, multi-material minimum structural compliance topology optimization problems is solved basedon the classical optimality criteria method. Three different types of steel material are used: SS400, SM570, UL700. The distribution of these three materials is considered by changing the participating volume of materials in the given shape. Material distribution is implemented with the use of 2 materials and 3 materials. The strain energy and the price of three steel types are used for comparison.

The aim of our research was to apply experimental design methodology in the optimization of N, N-Dimethyl- 4-nitrosoaniline (RNO, which is indictor of OH radical formation) degradation using gas mixing-circulation plasma process. The reaction was mathematically described as a function of four independent variables [voltage (X1), gas flow rate (X2), liquid flow rate (X3) and time (X4)] being modeled by the use of the central composite design (CCD). RNO removal efficiency was evaluated using a second-order polynomial multiple regression model. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) value of 0.9111, thus ensuring a satisfactory adjustment of the second-order polynomial multiple regression model with the experimental data. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the RNO removal efficiency and independent variables in a coded unit: RNO removal efficiency (%) = 77.71 + 10.04X1 + 10.72X2 + 1.78X3 + 17.66X4 + 5.91X1X2 + 3.64X2X3 - 8.72X2X4 - 7.80X1 2 - 6.49X2 2 – 5.67X4 2. Maximum RNO removal efficiency was predicted and experimentally validated. The optimum voltage, air flow rate, liquid flow rate and time were obtained for the highest desirability at 117.99 V, 4.88 L/min, 6.27 L/min and 24.65 min, respectively. Under optimal value of process parameters, high removal(> 97 %) was obtained for RNO.

본 연구는 도시유역에서 기존에 설치된 우수배제시설인 우수관로시스템의 제한적 규모로 인하여 시설규모를 초과하여 발생하는 호우에서 홍수로 인한 피해를 최소화하기 위한 소규모 저류지의 다중설치를 최적화 기법을 도입하여 분석을 수행하였다. 설계강우량을 초과하여 발생하는 호우에서는 우수거의 통수능 부족으로 저지대 등 상대적으로 홍수에 취약한 지점들에서 국지적이고 다발적인 침수가 불가피하게 되므로 유역하구에 대규모의 유수지 및 빗물펌프장의 설치로 해결되기 어려운 국지침수에 대비하기 위한 다중의 분산형 소규모저류지가 효율성이나 경제성에서 유리하다. 소규모저류지를 침수취약지점들을 중심으로 분산하여 설치하기 위한 최적위치 및 규모에 대하여 최적화 분석을 수행하였다. 또한 최적홍수저감효율 대비 경제적인 요소를 반영하기 위하여 홍수저감과 상반되는 최소개략설치비를 고려하여 모의를 수행하였다. 분석결과 설치비 대비 홍수저감이 최대로 되는 최적설계의 선택이 가능함을 확인할 수 있었다. 본 연구기법을 이용하면 홍수저감율과 설치비라는 상반된 조건에서의 최적 분산형 소규모 저류시설의 설계가 가능하며 또한 제한된 예산에서의 최적 저감시설의 설계나 홍수저감 목표량 대비 개략사업비의 추정도 가능할 것으로 판단된다. 비록 경제적인 측면이 개략공사비에 국한하여 유지관리비나 감가상각 및 홍수의 증감 등이 고려되지 못하였으나 현재의 시점에서 진보된 실무활용성이 있다고 판단된다.

The SCR (selective catalytic reduction) system is highly-effective technique for NOx reduction from exhaust gases. In this study, the effects of the direction and size of nozzle and the ammonia injection concentration on the performance of SCR system are analyzed by using the computational fluid dynamics method. When the nozzle is arranged in zigzaged direction which is normal to exhausted gas flow, it is shown that the uniformity of gas flow and the NH3/NO molar ratio is improved remarkably. With the change of the ammonia injection concentration from 0.2 vol%(wet) to 1.0 vol%(wet), the uniformity of gas flow shows a good results. As the size of nozzle diameter changes from 6 mm to 12 mm, the uniformity of gas flow is maintained well. It is shown that the uniformity of the NH3/NO molar ratio becomes better with decreasing the ammonia injection concentration and the size of nozzle diameter.

In this paper, a new direct search method, Near-Up Search method, is proposed for the discrete nonlinear structural optimization. The proposed method is illustrated and tested by the minimum weight structural optimization problem of 3D truss. The results of the trusses design show that the Near-Up Search method is much more efficient than Genetic Algorithm.

For the optimized design of the wind turbine tower, demonstrate the superiority of ability to resist the lateral load on the ICH-CFT, i.e. ability to resist the moment, compared to Steel Tubular Type that is mainly used in the existing, by using P-M Diagram

This study have interests in presenting the process of material optimization design. This study was designed by using design of experiment. To present the form of model and explore the optimal point of response surface model, central composite design(CCD) and Response Surface Methodology(RSM) were used in the design of the experiment and in the analysis of the results.

This study investigated the application of experimental design methodology to optimization of conditions of air-plasma and oxygen-plasma oxidation of N, N-Dimethyl-4-nitrosoaniline (RNO). The reactions of RNO degradation were described as a function of the parameters of voltage (X1), gas flow rate (X2) and initial RNO concentration (X3) and modeled by the use of the central composite design. In pre-test, RNO degradation of the oxygen-plasma was higher than that of the air-plasma though low voltage and gas flow rate. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the RNO removal efficiency and test variables in a coded unit: RNO removal efficiency (%) = 86.06 + 5.00X1 + 14.19X2 - 8.08X3 + 3.63X1X2 - 7.66X2 2 (air-plasma); RNO removal efficiency (%) = 88.06 + 4.18X1 + 2.25X2 - 4.91X3 + 2.35X1X3 + 2.66X1 2 + 1.72X3 2 (oxygen-plasma). In analysis of the main effect, air flow rate and initial RNO concentration were most important factor on RNO degradation in air-plasma and oxygen-plasma, respectively. Optimized conditions under specified range were obtained for the highest desirability at voltage 152.37 V, 135.49 V voltage and 5.79 L/min, 2.82 L/min gas flow rate and 25.65 mg/L, 34.94 mg/L initial RNO concentration for air-plasma and oxygen-plasma, respectively.

저등급 석탄인 갈탄(lignite)을 순환 유동층 가스화기(circulating fluidized bed gasifier)의 효과적인 가스화를 위한 공급탄으로 제조하기 위하여 모든 조건들은 동일하고 스크린의 크기만을 변경하여 목적하는 입도분포 특성을 달성하는 최적조건을 찾기 위한 실험을 수행하였다. 가스화기 공급탄은 0.045~1 mm 크기로 85 wt% 이상이 요구되며 이러한 입도분포를 갖는 공급탄을 제조하기 위해서는 경제적이면서도 효과적인 공정 설계가 반드시 필요하다. 따라서 본 연구는 중국산 갈탄을 해머밀로 효과적으로 분쇄하기 위하여 다구치 설계를 사용하였으며, 설계조건에 따른 실험결과 및 통계분석 결과 95% 유의수준에서 1차 스크린의 크기는 3 mm, 2차 스크린의 크기는 1.3 mm인 경우가 최적화된 조건인 것으로 나타났다.

The experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV process were mathematically described as a function of parameters power (X1), NaCl dosage (X2), initial pH (X3) and disinfection time (X4) being modeled by use of the Box-Behnken technique. The application of RSM using the Box-Behnken technique yielded the following regression equation, which is an empirical relationship between the residual E. coli number and test variables in actual variables: Ln (CFU) = 23.57 - 0.87․power - 1.87․NaCl dosage - 2.13․pH - 2.84․time - 0.09․powe r․time - 0.07․NaCl dosage․pH + 0.14․pH․time + 0.03․power 2 + 0.47․NaCl dosage 2 + 0.20․pH 2 + 0.33․time 2 . The model predictions agreed well with the experimentally observed result (R 2 = 0.9987). Graphical response surface and contour plots were used to locate the optimum point. The estimated ridge of maximum response and optimal conditions for the E. coli disinfection using canonical analysis was Ln 1.06 CFU (power, 15.40 W; NaCl dosage, 1.95 g/L, pH, 5.94 and time, 4.67 min). To confirm this optimum condition, the obtained number of the residual E. coli after three additional experiments were Ln 1.05, 1.10 and Ln 1.12. These values were within range of 0.62 (95% PI low)～1.50 (95% PI high), which indicated that conforming the reproducibility of the model.