• Corrosion Science and Technology
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• 제23권3호
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• pp.246-254
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• 2024

Recently, coal-fired power plants are experiencing many problems that they have never experienced before due to an increase in flexible operation. In particular, a two-phase flow accelerated corrosion on water wall tubes in a boiler has not been detected overseas or domestically. There is no response plan to deal with such corrosion problem either. However, oxide film damage and tube material corrosion due to a two-phase flow accelerated corrosion are being discovered on water wall boiler tubes of domestic coal-fired power plants recently. If this situation is severe, it can cause enormous damage such as tube rupture. Therefore, in this paper, in order to prepare a response plan for a two-phase flow accelerated corrosion on water wall tubes in the future, differences between a two-phase flow accelerated corrosion and a single-phase flow accelerated corrosion were investigated and an example of discovery of a two-phase flow accelerated corrosion on water wall tubes was presented.

• 환경정책연구
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• 제9권2호
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• pp.111-133
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• 2010

환경정책기본법에 근거하여 수립되는 환경보전계획은 친환경적인 공간구축을 위한 활용 가능성과 잠재성에도 불구하고 선언적이면서 형식적인 계획으로 사실상 인지되고 있다. 이러한 인식의 중요한 요인 중의 하나는 공간개발과 직접적인 관련성이 있는 공간계획(도시기본계획 등)이나 도시개발계획과의 연계성을 확보하지 못한 것에 기인하며, 이는 공간환경계획이라는 계획 간의 연계수단의 필요성으로 종결된다. 이에 환경보전계획의 활용성과 계획 간의 연계성 확보를 위한 공간환경계획의 수립을 위해 선행되어야 할 공간환경정보의 체계화를 제안하고자 하며, 이를 위해 기존의 환경정보를 파악하고 공간환경계획과의 연계방안에 대해서 살펴보고자 하였다. 이와 관련해서 국가차원 및 지자체 차원에서 구축하고 있는 공간정보시스템을 살펴보고, 환경매체별로 활용 가능한 공간정보를 분류하였다. 또한 9개의 환경매체별로 공간환경계획에 포함될 수 있는 공간정보 및 계획 항목을 도출하여, 기존의 공간정보시스템, 공간환경 현황정보, 공간환경 관리계획으로 이어지는 연계체계를 구축하였다. 나아가, 공간환경계획 활성화를 위해 공간환경정보 구축에 관한 개선사항을 제안하였다. 체계적인 공간정보 구축은 공간환경계획 수립을 용이하게 함으로써 환경보전계획을 강화하고 위상을 높임은 물론, 관련 공간계획과의 연계성 강화에도 기여할 것이다.

• Structural Monitoring and Maintenance
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• 제5권3호
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• pp.345-361
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• 2018

The set of processes performed to determine the dynamic characteristics of the constructed structures is named experimental modal analysis. Using experimental modal analysis and interpreting its results, structural failure can be assessed and then it would be possible to plan for their repair and maintenance. The purpose of the experimental modal analysis is to determine the resonance frequencies, mode shapes and Mode damping for the structure. Diverse methods for determining the shape of the mode by various researchers have been presented. There are pros and cons for each of these methods. This paper presents a method for determining the mode shape of the structures using the response spectrum in the experimental modal analysis. In the first part, the principles of the proposed method are described. Then, to check the accuracy of the results obtained from the proposed method, single and multiple degrees of freedom models were numerically and experimentally investigated.

• 한국염색가공학회지
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• 제8권2호
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• pp.35-42
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• 1996

Peroxodisulfates are being developed as low temperature bleaching agents for cotton fabrics to save the thermal energy. In this research we used the colar difference meter to determine the whiteness which peroxide booster will possibly make an effect on cotton fabric at the low temperature process using consist of temperature with different conditions agents, such as sodium hydroxide, sodium peroxodisulfate and potassium peroxodisulfate. The peroxide bleaching follows a laboratory experiments, using a statistical plan for three variables: the concentrations of hydrogen peroxide and sodium hydroxide and the temperature of bathing. The purpose of this research was to use the response surface analysis method to evaluate the relative importance of factors providing optimum whiteness. A ridge analysis of the data on whiteness response results in 3-D response surface diagrams for optimizing the concentrations of hydrogen peroxide and sodium hydroxide at about 42~52$^{\circ}C$.

• 소음진동
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• 제9권5호
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• pp.949-954
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• 1999

Speed-up and mass reduction of railway vehicle usually causes increased of the interior noise. One of the best ways to control the interior noise is to identify the noise level radiated from each of parts in the cabin. In this paper, we describe the method to estimate the interior noise nad evaluate the noise contribution to each of parts. This method is based that the sound pressure can be calculated by using the frequency response function and acceleration. According to analysis of the noise contribution, we validated that the noise radiated from the floor is the higher in the cabin. We also measured the noise distribution for the side and floor by using the microphone array in order to analyze the effect of the noise flowing into the cabin from the outdoors. Finally, we presented the plan of the interior noise reduction based on the noise levels radiated from each of parts.

• 전기학회논문지
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• 제57권12호
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• pp.2285-2290
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• 2008

Even though efficiency of coal-fired power plant is proportional to operating temperature, increasement of operating temperature is limited by a technological level of each power plant component. It is an alternative plan to increase operating pressure up to ultra super critical point for efficiency enhancement. It is difficult to control process of power plant in ultra super critical point because that point has highly nonlinear characteristics. In this paper, new control logic, Unit Response Optimizer Controller(URO Controller) which is based on Fuzzy logic and Model Predictive Controller, is introduced for better performance. Then its performance is tested and analyzed with design guideline.

• 대한산업공학회지
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• 제40권2호
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• pp.151-162
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• 2014

This study proposes an optimization model to plan the patient distribution and medical resource allocation considering the diverse characteristics of disaster. For reflecting the particularity of disaster response, we configured a few scenarios such as availability of emergency surgery of non-major medical staff and the change in number of patients estimated reflecting the uncertainty, urgency and convergence of disaster. And we finally tested the effects of the scenarios' combination on the objective function defined as maximum number of survival patients. Our experimental results are expected to highlight the significance of the proposed model as well as the applicability of scenarios under disaster response.

• Coupled systems mechanics
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• 제6권1호
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• pp.55-74
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• 2017

The evaluation of torsional effects on multistory buildings remains an open issue, despite considerable research efforts and numerous publications. In this study, a large number of multiple test structures are considered with normally distributed topological attributes, in order to quantify the statistically derived relationships between the torsional criteria and response parameters. The linear regression analysis results, depict that the center of twist and the ratio of torsion (ROT) index proved numerically to be the most reliable criteria for the prediction of the modal rotation and displacements, however the residuals distribution and R-squared derived for the ductility demands prediction, was not constant and low respectively. Thus, the assessment of the torsional parameters' contribution to the nonlinear structural response was investigated using artificial neural networks. Utilizing the connection weights approach, the Center of Strength, Torsional Stiffness and the Base Shear Torque curves were found to exhibit the highest impact numerically, while all the other torsional indices' contribution was investigated and quantified.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.1-9
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• 2023

The purpose of this study is to examine the disaster management system of local governments by diagnosing the current status of disaster management experts in Korea, deriving problems and improvement measures, and looking at local governments' total labor cost system. The status and status of disaster management personnel were compared and analyzed to find ways to improve the local government's disaster management response system under the Framework Act on Disaster and Safety Management in Korea. Considering Korea's reality, because national security and disaster management exist together, we devised a plan to improve on-site response capabilities and seek solutions by deriving the problems of the currently operating security and safety-related organizations.

• 응용통계연구
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• 제21권5호
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• pp.791-799
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• 2008

데이터 통화료 정액제는 일정 정액요금을 지불하고 데이터 통화를 일정액 이상 무료로 이용할 수 있는 데이터 부가 서비스 상품이다. 본 연구에서는 이동통신 A사의 TM에 의한 안심정액제 가입 고객의 모델 스코어를 활용하여 예상 가입가능성과 가입 후 유지가능성을 모두 향상시킬 수 있는 타겟팅 방법을 제안하고자 한다. 본 연구에서 제안한 타겟 모델을 적용하여 상위 30%를 타겟팅 할 경우 기존의 방법보다 안심정액제 TM 가입률은 15.1% 향상시키고 유지율은 8.2% 향상시키는 것으로 나타났다. 이는 고객의 성향 및 이용 패턴을 고려하여 고객관계관리(Customer Relationship Management: CRM)의 고객관점에서 고객가치(customer value)를 증대시킬 수 있을 뿐 아니라 A사 입장에서도 고객의 불만을 줄이고 고객유지(retention)를 증대시켜 수익성을 더욱 향상시킬 수 있을 것으로 기대된다.