• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1306-1313
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• 2018

The randomness and incipient nature of certain faults in reactor systems warrant a robust and dynamic detection mechanism. Existing models and methods for fault diagnosis using different mathematical/statistical inferences lack incipient and novel faults detection capability. To this end, we propose a fault diagnosis method that utilizes the flexibility of data-driven Support Vector Machine (SVM) for component-level fault diagnosis. The technique integrates separately-built, separately-trained, specialized SVM modules capable of component-level fault diagnosis into a coherent intelligent system, with each SVM module monitoring sub-units of the reactor coolant system. To evaluate the model, marginal faults selected from the failure mode and effect analysis (FMEA) are simulated in the steam generator and pressure boundary of the Chinese CNP300 PWR (Qinshan I NPP) reactor coolant system, using a best-estimate thermal-hydraulic code, RELAP5/SCDAP Mod4.0. Multiclass SVM model is trained with component level parameters that represent the steady state and selected faults in the components. For optimization purposes, we considered and compared the performances of different multiclass models in MATLAB, using different coding matrices, as well as different kernel functions on the representative data derived from the simulation of Qinshan I NPP. An optimum predictive model - the Error Correcting Output Code (ECOC) with TenaryComplete coding matrix - was obtained from experiments, and utilized to diagnose the incipient faults. Some of the important diagnostic results and heuristic model evaluation methods are presented in this paper.

• 대한건축학회논문집:구조계
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• 제34권5호
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• pp.3-11
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• 2018

Since the tensegrity structure is flexible and variable, the study on the mobility to the tensegrity has been conducted. However, it is difficult to apply the tensegrity to the architecture field due to several limits. This paper describes the methodology for the analysis of the shape change process of single prism tensegrity structure as an initial study. To apply the tensegrity structure to the architectural field, the assemblage and mathematical formulation procedures of the single prism tensegrity structures are carried out. And single prism tensegrity are presented to the computational strategies for simulate the shape change of those structures. Next, the investigation of structural behaviors through various cases of target displacements is described. Also, the summary of these methods in algorithms is illustrated. As a result it is confirmed that the single prism tensegrity structure model converges 99% on average to a given target node by using the proposed algorithm. Therefore, it is confirmed that the proposed algorithm and program are suitable for shape change analysis of single prism tensegrity structure model.

• Advances in concrete construction
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• 제11권1호
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• pp.1-9
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• 2021

This article discusses the issue of optimizing controller design issues, in which the artificial intelligence (AI) evolutionary bat (EB) optimization algorithm is combined with the fuzzy controller in the practical application of the building. The controller of the system design includes different sub-parts such as system initial condition parameters, EB optimal algorithm, fuzzy controller, stability analysis and sensor actuator. The advantage of the design is that for continuous systems with polytypic uncertainties, the integrated H2/H∞ robust output strategy with modified criterion is derived by asymptotically adjusting design parameters. Numerical verification of the time domain and the frequency domain shows that the novel system design provides precise prediction and control of the structural displacement response, which is necessary for the active control structure in the fuzzy model. Due to genetic algorithm (GA), we use a hierarchical conditions of the Hurwitz matrix test technique and the limits of average performance, Hierarchical Fitness Function Structure (HFFS). The dynamic fuzzy controller proposed in this paper is used to find the optimal control force required for active nonlinear control of building structures. This method has achieved successful results in closed system design from the example.

• 청정기술
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• 제28권1호
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• pp.32-37
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• 2022

Food waste is produced from food factories, food services, and home kitchens. The generated mass reached 5.4 million tons/year in 2020. The basic management technology for such waste has been biological degradation under an anaerobic environment. However, the whole process is intrinsically slow and considerably affected by the inner physicochemical properties of the waste and other surrounding conditions, which makes optimization of the process difficult. The most promising options to counter this massive generation of waste are eco-friendly treatments or recycling. As a preliminary step for these options, attempts were made to evaluate the feasibility and usability of three simulative models based on reaction kinetics. Model (A) predicted relative changes over reaction time for reactant, intermediate, and product. Overall, an increased reaction rate produced less intermediate and more product, thereby leading to a shorter total reaction time. Particle diminishing model (B) predicted reduction of the total waste mass. The smaller particles diminished faster along with the dominant effect of microbial reaction. In Model (C), long-chain cellulose was predicted to transform into reducing sugar. At a standard condition, 48% of cellulose molecules having 10⁵ repeating units turned into reducing sugar after 100 h. Also it was found that the optimal enzyme concentration where the highest amount of remnant sugar was harvested was 1 mg L^-1.

• Journal of the Korean Wood Science and Technology
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• 제49권3호
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• pp.254-266
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• 2021

Using forest resources involves solving complex and diverse tasks. At the same time, one of the key goals in the field is improving the quality of forest infrastructure. This direction requires adequate mathematical and economic justification. Moreover, creating an effective infrastructure will not only increase the accessibility and usage volumes of wood and other forest resources, but also contribute to the development of continuous and sustainable forest management. The existing practice of making decisions in terms of the organizational and technological aspects of logging, based on the personal experiences of managers or leading specialists in enterprises, hinders the achievement of constant optimal efficiency. The paper presents results that are a continuation of the research cycle of the authors' team in the fields of optimization and algorithmization of various logging processes. The focus of the study lies in the processing and movement of wood resources, the most valuable products of the investigated groups of enterprises. To this end, the paper presents a developed algorithm for determining an effective technological chain of transportation in logging operations, and for improving loading and unloading processing operations under dynamic natural and production conditions. This algorithm serves as the methodological basis for designing logging infrastructure in a dynamically changing environment.

• 한국인터넷방송통신학회논문지
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• 제23권1호
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• pp.151-156
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• 2023

본 논문은 주어진 예산과 광고를 접하는 최소 인원수를 초과하는 제약조건을 만족시키면서 신제품에 대한 인지도를 극대화시키기 위해 다수의 광고매체들 중에서 어느 광고매체를 몇 회 광고해야 하는지를 결정하는 최적화 문제를 다룬다. 본 문제에 대해 지금까지는 선형계획법 (LP) 소프트웨어 패키지를 활용하는 수학적 접근법만이 활용되고 있으며, 다항시간 알고리즘은 제안되지 않고 있는 실정이다. 본 논문은 이 문제에 대해 O(nlog n) 수행 복잡도의 다항시간으로 최적 해를 얻을 수 있는 휴리스틱 알고리즘을 제안한다. 제안된 방법은 광고매체를 가장 경제적으로 선정하는 평가기준을 제안하였으며, 이 평가기준을 적용하여 광고매체 선정과 광고횟수를 결정하였다. 제안된 알고리즘은 Excel을 활용하였음에도 불구하고, 실험 데이터에 적용한 결과 LP와 동일한 결과를 얻었다.

• 산업경영시스템학회지
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• 제45권4호
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• pp.217-224
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• 2022

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

• Steel and Composite Structures
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• 제48권6호
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• pp.625-639
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• 2023

In this paper, a Taguchi-based finite element method (FEM) has been proposed and implemented to assess optimal design parameters for minimum static deflection in laminated composite plate. An orthodox mathematical model (based on higher-order shear deformation plate theory and Green-Lagrange geometrical nonlinearity) has been used to compute the nonlinear central deflection values of laminated composite plates according to Taguchi design of experiment via a self-developed MATLAB computer code. The lay-up scheme, aspect ratio, thickness ratio and the support conditions of the laminated composite plate structure were designated as the governable design parameters. Analysis of variance (ANOVA) is used to investigate the effect of diverse control factors on the nonlinear static responses. Moreover, regression model is developed for predicting the desired responses. The ANOVA revealed that the lay-up scheme alongside the support condition plays vital role in minimizing the central deflection values of laminated composite plate under uniformly distributed load. The conformity test results of Taguchi analysis are also in good agreement with the numerical experimentation results.

• 한국식생활문화학회지
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• 제25권2호
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• pp.216-224
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• 2010

This study was conducted to aid in the development of the optimal recipe for chocolate with fermented and aged garlic extract (Allium sativum var. pekinense). We added garlic extract in order to increase the nutritional value of the chocolate. The optimal sensory composite recipe was determined, following Central Composites for chocolate with different levels of fermented and aged garlic extract (A) and cream (B), while analysis was performed by Response Surface Methodology, from the date that the sensory evaluation was performed. Ten experimental recipes, including 2 reference points in the composition, were selected. The compositional and functional properties were measured, and physical and sensory values were applied to the mathematical models. Perturbation plots showed the influence of each ingredient on the final product. Measurements showed significant values in lightness, sweetness, pH, hardness and cohesiveness, while sensory measurements showed significant values in color, texture, sourness, bitterness and overall quality. The optimum formulations were calculated by numerical and graphical methods, as being 34.61g fermented and aged garlic extract and 72.68g cream for each 200g chocolate. As well it was revealed that the aptitude of chocolate was more influenced by fermented garlic extract than it was by cream.

• 한국식생활문화학회지
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• 제24권3호
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• pp.321-330
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• 2009

This study was conducted to develop a recipe for a nutritional cookie containing chungkukjang powder that had a composition of ingredients and a texture that resulted in a high preference by all age groups. Wheat flour was partially substituted with chungkukjang powder to reduce its content. Response surface methodology was then used to analyze the measured results, which showed 16 experimental points including 2 replicates for chungkukjang powder, butter and sugar. The compositional and functional properties were then measured, after which these values were applied to a mathematical model. A canonical form and perturbation plot revealed the influence of each ingredient on the final mixture. The results of the sensory evaluation showed significant values with respect to color (p<0.01), texture (p<0.05) and overall quality (p<0.05). Taken together, the results of this study indicated that the optimal ratio was 26.57 g of chungkukjang powder, and 82.08 g of butter for every 52.36 g of sugar. The physical and chemical sensory measurements were then evaluated by a t-test, and the results revealed significant differences in the flavor of the optimized cookie when compared to the control cookie.