The optimization of dewatering and impregnation soaking (DIS) process for a concentrated Aloe vera product was investigated using Taguchi method in combination with desirability function analysis. Polyethylene glycol (PEG) as osmotic agent was adopted, and soaking temperature (T), immersion time (t), PEG concentration (C), PEG molecular weight (MW), and thickness of Aloe vera leaf slice (x) were selected as affecting variables. L16 (45) orthogonal array was designed by Taguchi method with four parameters such as water loss, solid gain, glucomannan, and anthraquinone contents as objective functions. An overall quality index was transformed from individual objective functions, and was optimized finally. The optimal setting for maximum overall desirability was obtained at 55oC (T), 2 hr (t), 40% w/v (C), 0.5 cm (x), and 4,000 Da. (MW). The obtained overall desirability was 0.7842. The order of affecting factors was T>C>x>MW≈x>t and the experimental results under optimum condition were similar to the prediction of an overall desirability of 0.8384. Also, it was found that the optimized DIS condition could be reproduced for a minimally processed Aloe vera product with high quality.

본 연구는 항산화활성을 나타내는 식물추출물을 이용하여 가축용 사료첨가제를 개발하기 위한 목 적으로 수행되었다. 총 10가지의 식물들(익모초, 뽕나무 잎, 두충, 민들레, 엄나무, 삼백초, 꾸지뽕나 무, 감나무 잎, 헛개나무 및 가시오갈피)을 열수추출 방법을 이용하여 추출물을 준비하였고, 식물추 출물들의 총 폴리페놀, 총 플라보노이드 함량을 조사하였으며, 항산화활성을 측정하였다. 항산화활성 의 측정 후, 모든 추출물들이 혼합된 상태에서 항산화활성 향상에 효과를 나타내는 추출물들을 부분 요인실험설계법의 일종인 Plackett-Burman 실험설계법을 이용하여 선별하였으며 우수한 항산화활 성을 보이는 식물추출물들을 통계적인 방법인 혼합물실험설계법을 이용하여 조합하였고 이 조합들에 서 얻어진 반응들은 root mean square prediction error측정법을 적용하여 계산하였다. 유의적으로 긍정적효과를 나타낸 식물추출물들로는 뽕나무 잎, 감나무 잎 및 가시오갈피로 나타났다. 이 세 가지 식물추출물들의 최적 혼합비율을 도출하기 위하여 통계적인 방법을 적용한 결과로 뽕나무 잎 추출물, 감나무 잎 추출물 및 가시오갈피 추출물의 혼합비율이 0.44 : 0.28 : 0.28에서 가장 우수한 항산화활성 이 나타났다. 본 연구의 결과에 의하면 통계적인 방법을 이용하여 항산화활성이 우수한 식물추출물의 조 합을 용이하게 도출할 수 있고 이를 기초로 추가적인 연구에 응용할 수 있을 것으로 사료된다.

In this study, a theoretical investigation of optimized sleeper spacing which can suppress resonances of a railway track is attempted. To achieve this, we introduced a minimization problem in which the objective function is given by the wave transmittance and the design variable is defined by sleeper distribution. In the analysis the rail is modeled by a Timoshenko beam and the sleeper is represented by a mass. The infinite track analysis is realized by attaching the transmitting boundaries at both ends of the finite optimization region. Through numerical analyses the sleeper spacing effective in reduction of the transmittance is discussed. Furthermore, the feasibility of the proposed method is validated in the aspect of vibration reduction through response analyses for a harmonic load.

A level set based topological shape optimization method for nonlinear structure considering hyper-elastic problems is developed. To relieve significant convergence difficulty in topology optimization of nonlinear structure due to inaccurate tangent stiffness which comes from material penalization of whole domain, explicit boundary for exact tangent stiffness is used by taking advantage of level set function for arbitrary boundary shape. For given arbitrary boundary which is represented by level set function, a Delaunay triangulation scheme is used for current structure discretization instead of using implicit fixed grid. The required velocity field in the actual domain to update the level set equation is determined from the descent direction of Lagrangian derived from optimality conditions. The velocity field outside the actual domain is determined through a velocity extension scheme based on the method suggested by Adalsteinsson and Sethian(1999). The topological derivatives are incorporated into the level set based framework to enable to create holes whenever and wherever necessary during the optimization.

A topology optimization method for phononic crystals is developed for the design of sound barriers, using the level set approach. Given a frequency and an incident wave to the phononic crystals, an optimal shape of periodic inclusions is found by minimizing the norm of transmittance. In a sound field including scattering bodies, an acoustic wave can be refracted on the obstacle boundaries, which enables to control acoustic performance by taking the shape of inclusions as the design variables. In this research, we consider a layered structure which is composed of inclusions arranged periodically in horizontal direction while finite inclusions are distributed in vertical direction. Due to the periodicity of inclusions, a unit cell can be considered to analyze the wave propagation together with proper boundary conditions which are imposed on the left and right edges of the unit cell using the Bloch theorem. The boundary conditions for the lower and the upper boundaries of unit cell are described by impedance matrices, which represent the transmission of waves between the layered structure and the semi-infinite external media. A level set method is employed to describe the topology and the shape of inclusions. In the level set method, the initial domain is kept fixed and its boundary is represented by an implicit moving boundary embedded in the level set function, which facilitates to handle complicated topological shape changes. Through several numerical examples, the applicability of the proposed method is demonstrated.

Geometric configurations such as hull shape, wall thickness, stiffener layout, and type of construction materials are the key factors influencing the structural performance of pressure hulls. Traditional theoretical approach provides quick and acceptable solutions for the design of pressure hulls within specific geometric configuration and material. In this paper, alternative approaches that can be used to obtain optimal geometric shape, wall thickness, construction material configuration and stiffener layout of a pressure hull are presented. CAE(Computer Aided Engineering) based design optimization tools are utilized in order to obtain the required structural responses and optimal design parameters. Optimal elliptical meridional profile is determined for a cylindrical pressure hull design using metamodel-based optimization technique implemented in a fully-integrated parametric modeler-CAE platform in ANSYS. While the optimal composite laminate layup and the design of ring stiffener for a thin-walled pressure hull are obtained using gradient-based optimization method in OptiStruct. It is noted that the proposed alternative approaches are potentially effective for pressure hull design.

Logistics cost of domestic company has been improved continuously and annually, it is still higher than other main comparative countries. So, in this study, as optimizing the logistic network of distribution, it was trying to find methods decreasing logistics cost and storage cost, which occupies 86% of logistics cost of companies. through the efficiency of transportation and delivery routing, it could be also possible to decrease the logistics cost. And, it is also checked to find the logistics cost could be decreased by 10% by optimizing the routes of transportation and delivery, improving the transportation mode, etc.

It has been recognized as an important issue to design optimally a firm's logistics network for minimizing logistics cost and maximizing customer service. It is, however, not easy to get an optimal solution by analyzing trade-off of cost factors, dynamic and interdependent characteristics in the logistics network decision making. Although there has been some developments in a system which helps decision making for logistics analysis, it is true that there is no system for enterprise-wise's on-site support and methodical logistics decision. Specially, E-biz process along with information technology has been made dramatic advance in a various industries, there has been much need for practical education closely resembles on-site work. The software developed by this study materializes efficient algorithm suggested by recent studies in key topics of logistics such as location and allocation problem, traveling salesman problem, and vehicle routing problem and transportation and distribution problem. It also supports executing a variety of experimental design and analysis in a way of the most user friendly based on Java. In the near future, we expect that it can be extended to integrated supply chain solution by adding decision making in production in addition to a decision in logistics.

The objective of this study was to determine the optimum mixing ratio of Opuntia humifusa powder and sugar in the preparation of muffin. The optimal sensory composite recipe was determined by following the central composites for muffin with different levels of Opuntia humifusa powder (A) and sugar (B). The analysis was performed using the response surface methodology, and the sensory evaluation was performed with the data. Ten experimental recipes, including two with reference points in the composition, were selected. The compositional and functional properties were measured, and the physical and sensory values were applied to the mathematical models. Perturbation plots showed the effects of each ingredient on the final product. Measurements showed significant values in lightness (p<0.05), sweetness (p<0.05), hardness (p<0.05), gumminess (p<0.05) and cohesiveness (p<0.01). The sensory measurements showed significant values in color (p<0.05), flavor (p<0.05), appearance (p<0.05), softness (p<0.05) and overall quality (p<0.05). Based on the numerical and graphical methods, the optimal formulation was determined to be 6.10 g of Opuntia humifusa powder and 82.61 g of sugar.

The purpose of this study was to investigate the antioxidative effects of Opuntia humifusa and determine the optimal mixing ratio of Opuntia humifusa powder and eggs for the preparation of pasta. In regard to its antioxidant effects, Opuntia humifusa powder had a total phenolic content and DPPH free radical scavenging activity of 6.64 mg/g and 90.12%, respectively. We used response surface methodology to obtain ten experimental points (including two replicates for Opuntia humifusa powder and egg) and Opuntia humifusa pasta formulation was optimized using rheology. Yellowness (p<0.001) displayed a linear model pattern, whereas lightness (p<0.01) and redness (p<0.01) were described by a quadratic model pattern. Mechanical properties showed significant values in hardness (p<0.5), chewiness (p<0.5), gummiess (p<0.5), and cohesiveness (p<0.5). The sensory evaluation parameters showed significant differences in color (p<0.5), appearance (p<0.5), flavor (p<0.5), texture (p<0.5) and overall quality (p<0.5). The optimum formulations processed by numerical and graphical optimization were found to be 7.30 g of Opuntia humifusa powder and 31.55 g of egg.

This study was conducted to develop a method to change the color of traditional Dongchimi using natural dyes to meet changing consumer demands. It was intended to improve the manufacturing process ability for color Dongchimi, and the best optimum extraction solvent and method from the natural dyes were proven to be confirmed and valid. The extraction process was evaluated using different solvents including distilled water, 20% ethyl alcohol, and 1% citric acid, and the quantity of the extracted anthocyanin was then measured based on the absorbance. The greatest absorbance was observed when 1% citric acid was used. Based on these findings, it would be most efficient to allow the traditional Dongchimi to produce citric acid naturally instead of using artificial additives during its production. Celosia cristata L. was extracted in its largest quantity when reacted with 20% ethyl alcohol. Therefore, instead of applying Celosia cristata L. to Dongchimi as the sub-ingredient during the preparatory stage, it will be more efficient to use Celosia cristata L. as the fractional ingredient in order to first extraction.

본 연구는 Y 정수장의 세라믹 정밀여과막 공정을 위한 최적의 약품세척 조건을 도출하고자 수행되었다. 세라믹 막 공정의 전처리로 오존과 응집공정이 있는 A계열의 경우 응집공정만 있는 B계열에 비해 9배 정도 잦은 약품세척(CIP)를 실시하였다. 이는 전처리 공정의 차이로 인하여 A와 B계열의 막오염현상이 다르게 나타난 근본적인 원인 이외에 막제조업체가 제시한 CIP 방법이 부적절한 것으로 조사되었다. 즉, CIP 회복률이 보정여과유속이 아니라 보정차압을 기준으로 계산되어 과대평가되었을 뿐만 아니라 구연산이 철산화물에 의한 파울링을 효과적으로 제거하지 못했기 때문이었다. 따라서 1단계 산세척 약품종류를 달리하여 CIP 효율을 평가한 결과 황산(0.1 N)과 구연산(1%)를 혼합하여 사용한 경우 회복률이 가장 높았고, 황산(0.1 N)만을 사용한 경우 회복률이 가장 낮은 것으로 나타났다. 그러나 황산의 농도를 0.3 N로 높인 결과 산세척 효율은 증가하였으나 알칼리세척 회복률이 낮아져 총회복률은 0.1 N 황산을 사용한 것과 유사하였다. 산과 알칼리세척 순서를 바꿔서 CIP를 수행한 결과 산세척을 먼저 수행시 CIP 효율이 더 높은 것으로 나타났다.

온도가 수확율과 수확기간에 미치는 영향은 방임과 솎음 공히 온도가 낮을수록 발이소요일이 길었고, 수학소요일도 같은 경향을 보였다. 수확률에 있어서 13℃에서는 91%, 17℃에서는 90.3%, 15℃에서는 95.8%로 가장 좋은 결과를 보였다. 온도가 낮은 것은 발이가 불량하여 수확률이 떨어진 것이고, 17℃ 조건에서는 갈반병이 발생하여 수확률이 떨어졌다. 솎음처리구에서 품질은 생육온도가 13, 15, 17℃일때 각각 7.5, 8.1, 7.7로 15℃ 처리가 가장 우수하였고, 수확량에 있어서는 17℃ 처리에서 100.0g으로 가장 많았다. 방임처리구에서의 온도의 영향은 솎음처리구와 마찬가지 경향으로 13, 15, 17℃일때 품질은 각각 4.6, 5.9, 5.1로 15℃가 가장 우수하였다. 무게에 있어서는 15℃처리에서 107.2g으로 가장 수량이 많았다. 생육시기별 온도를 달리 적용하였을 경우, Ⅱ조건(17℃ 발이기(뒤집기전, 7~8일)→16℃원기신장기(솎기전, 4~5일)→15℃ 신장기(솎기이후))가 생육소요일수가 16일로 가장 짧았으며, 수확량도 방임의 경우 다른 처리에 비해 22.4, 9.0% 증수되었다. 솎기구의 경우 품질이 8.1로 다른 처리구 7.1과 7.9보다 우수하였다. 총생산량에 있어서는 17.4, 4.0% 많았다.

The demand for facility used in producing multi-products is changed dynamically for discrete and finite time periods. The excess or the shortage for facility is occurred according to difference of the facility capacity size and demand for facility through given time periods. The shortage facility is met through the outsourcing production. The excess facility cost is considered for the periods that the facility capacity is greater than the demand for the facility, and the outsourcing production cost is considered for the periods that the demand for facility is greater than the facility capacity. This paper addresses to determine the facility capacity size, outsourcing production products and amount that minimizes the sum of the facility capacity cost, the excess facility cost and the outsourcing production cost. The characteristics of the optimal solution are analyzed, and an algorithm applying them is developed. A numerical example is shown to explain the problem.

본 연구에서는 항암효과가 뛰어난 차가버섯의 초음파 추출 공정 최적화를 위해 반응표면 분석법으로 모니터링하여 최적 추출 조건을 설정하였다. 중심합성계획법에 따라 추출 시간(), 에탄올 농도(), 추출 온도()을 요인변수로 하고 추출 수율(), 총 페놀함량(), 총 플라보노이드함량(), 갈색도()를 종속변수로 하여 시행 하였다. 실험 결과 추출 수율은 에탄올 농도와 추출 온도에 영향을 받음을 알 수 있었다. 안장점에서 추출 조건이 추출 시간 20.47min(), 에탄올 농도 42.85%(), 추출 온도 ()일 때, 최대값 18.02%로 나타났다. 총 페놀함량 또한 에탄올 농도와 추출 온도에 영향을 크게 받았다. 최대값은 71.57mg GAE/g으로 나타났으며 이때의 추출 조건은 추출시간 21.60min(), 에탄올 농도 45.19%(), 추출 온도 ()로 나타났다. 총 플라보노이드함량은 추출 온도의 영향을 받은 것으로 나타났고 안장점에서 추출 조건은 추출 시간 22.53min(), 에탄올 농도 46.37%(), 추출온도 ()였고 최대값은 35.98mg RE/g으로 예측되었다. 갈색도는 추출 시간, 에탄올 농도, 추출 온도 이 세가지 조건 모두에 영향을 크게 받았다. 안장점일 때의 추출시간 22.00min(), 에탄올 농도 46.89%(), 추출 온도 ()의 조건에서 최대값이 예측되었다. 앞에서 얻은 결과들을 바탕으로 contour map을 분석한 결과 추출시간 21.50min, 에탄올 농도 44.87%, 추출 온도 의 최적 추출 조건이 예측되었다.

This paper describes the structural design and optimization of sinusoidally corrugated web girder by using EUROCODE (EN 1993-1-5). The optimum design methodology and characteristics of the optimal cross-section are discussed. We investigate a shear buckling and the concerned standards for corrugated web and explain the equations to obtain a critical stress according to buckling type. In order to perform optimization, we consider an objective function as minimum weight of the girder and use the constraint functions as slenderness ratio and stresses of flanges as well as corrugated web and deflection. Genetic Algorithm is adopted to search a global optimum solution for this mathematical model. For numerical example, the clamped girder under the concentrated load is considered, while the optimum cross-sectional area and design variables are analyzed. From the results of the adopted example, the optimum design program of the sinusoidally corrugated web girder is able to find the suitable solution which satisfied a condition subject to constraint functions. The optimum design shows the tendency to decrease the cross-sectional area with the yielding strength increase and increase the areas with load increase. Moreover, the corrugated web thickness shows a stable increase concerning the load.

This study presents the effectiveness of a composite structure at improving blast resistance. The proposed composite structure consists of carbon fiber reinforced polymer (CFRP) and steel layers. While CFRP layer is used for blast energy reflection due to its high strength, steel layer is used for blast energy absorption due to its high ductility. A dynamic model is used to simulate the elastoplastic behavior of the proposed composite structure subject to blast load. Considering the magnitude variations of a blast event, the probability of failure of each layer is evaluated using reliability analysis. By assigning design probability of failure of each layer in the composite structure, the thickness of layers is optimized. A case study for the design of CFRP-steel composite structure subjected to an uncertain blast event is also presented.

본 연구의 주된 목적은 대한민국 주변도의 제작에 가장 적절한 투영법이 무엇인지를 결정하는 것이다. 이 목적을 달성하기 위해 다음과 같은 구체적인 연구과제를 설정한다. 첫째, 기제작된 지도와 투영법 선정의 가이드라인을 참조하여 몇 개의 후보 투영법을 선정한다. 둘째, 왜곡도 분석 기법에 대한 상세한 리뷰를 통해 투영 왜곡 분석을 위한 기본 방향을 설정한다. 셋째, GIS-기반 투영 왜곡 분석을 실시하고 그 결과를 바탕으로 최종의 투영법을 선정한다. 주요 연구 결과를 요약하면 다음과 같다. 첫째, 람베르트 정형원추도법, 알베르스 정적원추도법, 람베르트 정적방위도법, 그리고 정거방위도법이 일차적인 후보 투영법으로 선정되었다. 둘째, 극소 스케일의 국지적 왜곡도 지수를 사용하는 것이 가장 적절하며, 국지적 왜곡도의 값이 실질적으로 산출되어 공간적 분포의 시각화나 통계량 계산을 위해 사용되어야 한다는 점이 인식되었다. 셋째, 투영 왜곡 분석을 위한 플랫폼으로 PDAT(Projection Distortion Analysis Tool)가 선정되었는데, 이것은 국지적 왜곡도 지수에 기반하고 있으며, GIS 상에서 투영 왜곡 분석을 할 수 있는 환경을 제공한다. PDAT를 통해 투영 왜곡 분석이 실시되었고, 그 결과에 대한 종합적인 검토 결과 람베르트 정적방위도법이 최종적인 투영법으로 선정되었다. 본 연구는 대한민국 전도에 대한 적절한 투영법이 무엇인지에 대한 논의에 많은 시사점을 제공할 것으로 보인다.