• Nuclear Engineering and Technology
• /
• 제53권6호
• /
• pp.1731-1735
• /
• 2021

The operation of the nuclear reactor requires accurate and fast methods and techniques for analysing its kinetics. These techniques become even more important when the MOX-fuel is used due to the lower value of delayed neutron fraction 𝛽 for ²³⁹Pu. Based on a Birth-and-Death process review, the mathematical model of thermal reactor core has been proposed different from existing ones. The analytical method for thermal point-reactor parameters evaluation is described within this work. The proposed method is applied for analysis of the unsteady transient processes taking place in a thermal reactor at its start-up or shutdown power change, as well as during small accidental power variation from the rated value. Theoretical determination of MASURCA reactor core reactivity through the analysis of experimental data on neutron time spectra was made.

• 산업경영시스템학회지
• /
• 제40권3호
• /
• pp.76-82
• /
• 2017

Recently, the material industry in the world has started appreciating the value of new materials that can overcome the limitation of steel material. In particular, new materials are expected to play a very important role in the future industry, demonstrating superior performance compared to steel in lightweight materials and ability to maintain in high temperature environments. Carbon materials have recently increased in value due to excellent physical properties such as high strength and ultra lightweight compared to steel. However, they have not overcome the limitation of productivity and price. The carbon materials are classified into various composites depending on the purpose of use and the performance required. Typical composites include carbon-glass, carbon-carbon, and carbon-plastic composites. Among them, carbon-carbon composite technology is a necessary technology in aviation and space, and can be manufactured with high investment cost and technology. In this paper, in order to find the optimal conditions to achieve productivity improvement and cost reduction of carbon material densification process, the correlation between each process parameters and results of densification is first analyzed. The main process parameters of the densification process are selected by analyzing the correlation results. And then a certain linear relationship between major process variables and density of carbon materials is derived by performing a regression analysis based on the historical production result data. Using the derived casualty, the optimal management range of major process variables is suggested. Effective process operation through optimal management of variables will have a great effect on productivity improvement and manufacturing cost reduction by shortening the lead time.

• 수산경영론집
• /
• 제42권2호
• /
• pp.47-68
• /
• 2011

Values are lasting beliefs that are at the center of human behavior and not be often changed. Different values make different behaviors, and similar values form similar behaviors. Consumers' values affect not only the cognitive process but also behaviors in a powerful and comprehensive way. There have been many studies regarding prediction of consumer patterns and identification, measurement methods of values. This is because if we can accurately measure the value system, it can be used in many areas of marketing such as market segmentation, new product development, and advertisement. In case of seafood, it is also necessary to make marketing strategies by segmenting consumers based on their value systems. The objectives of this study are as follows: First, it is to find out the connection process from the properties of seafood products that consumers consider important, to the benefits, and finally to the values they pursue by applying the means-end chain theory, using the Laddering method. Second, using a two-step cluster analysis, we aim to segment seafood markets based on consumers' values and investigate characteristics of segmented markets. Based on objectives, it is expected that this study would provide informations on seafood consumers and help to establish seafood marketing strategies for producers and distributors. Analytical results of the value system using a means-end chain theory indicated that there were seven complete links, that is, ladders among fresh seafood products. In case of processed seafood products, there were total 9 complete ladders. The empirical analytical results of market segmentation according to the values showed fresh seafood products were divided into three groups. In case of processed seafood products were segmented into two groups.

• 한국산학기술학회논문지
• /
• 제13권8호
• /
• pp.3578-3585
• /
• 2012

유탕면류의 HACCP(Hazard Analysis Critical Control Point) 시스템 구축을 위하여 유탕 공정-CCP(Critical Control Point)에 대한 미생물학적(Biological hazards)과 화학적(Chemical hazards) 한계 기준 설정을 위한 목적으로 수행하였으며, 경기도 이천 소재의 P사에서 실행하였다. 유탕공정은 각각의 시간과 온도 측정에 따라 미생물학적, 화학적 위해요소를 제거하거나 감소에 대해 실험하였다. 실험결과 Standard plate count와 식중독균은 유탕공정(Temperature : $145{\pm}10^{\circ}C$, Time : $75{\pm}30$ sec)에 의해 검출되지 않았다. 유탕공정에 의해 생성되는 화학적 위해 기준의 산가는 법적 기준치인 0.6보다 낮은 0.2 이하였다. 증숙실과 유탕실의 공중낙하균을 측정한 결과 3 CFU/mL, 3 CFU/mL 검출되었다. 따라서 유탕공정의 CCP-BC는 일반세균과 식중독균, 산화생성물 생성을 예방, 제거하는데 좋은 대안책이 될 것이다. 결론적으로 HACCP을 위해 유탕공정에 대한 한계기준설정, 모니터링방법, 개선조치, 검증방법, 교육, 기록관리가 필요하다고 생각된다.

• Korea-Australia Rheology Journal
• /
• 제19권1호
• /
• pp.27-33
• /
• 2007

The co-extrusion of multi-layer films has been studied with the focus on its process stability. As in the single-layer film casting process, the productivity of the industrially important multi-layer film casting and the quality of thus produced films have often been hampered by various instabilities occurring in the process including draw resonance, a supercritical Hopfbifurcation instability, frequently encountered when the draw ratio is raised beyond a certain critical value. In this study, this draw resonance instability along with the neck-in of the film width has been investigated for a three-layer film casting using a varying width non-isothermal 1-D model of the system with Phan-Thien and Tanner (PTT) constitutive equation known for its robustness in portraying extensional deformation processes. The effects of various process conditions, e.g., the aspect ratio, the thickness ratio of the individual film layers, and cooling of the process, on the stability have been examined through the nonlinear stability analysis.

• 경영과학
• /
• 제20권1호
• /
• pp.149-163
• /
• 2003

The emergence of Internal has established a huge virtual exchange market, and the innovative e-commerce has changed a way of distributing goods and services. This paper concerns the issues of customer's loyalty to maintain the customer retention between individual and Internet shopping mall. We use the concept of customer's perceived value, satisfaction, and trust, in order to explore and explain the formation process of customer loyalty. A survey data has been collected through the hep of internet research institution. A statistical analysis shows that a subset of customer's perceived value has positive Impact on satisfaction, which in turn has also positive influence on trust, Increasing the level of customer's loyalty. We also provide a brief discussion of strategic guidelines about analytic results.

• 통상정보연구
• /
• 제10권3호
• /
• pp.3-21
• /
• 2008

This research investigates the strategy for application of E-Trade to SMEs to analyze the economic effect of e-trade. And the influence of the proliferation of e-business and e-trade upon the industrial business conditions, value-chain, and business activities is also analyzed. The subjects of the inquiry are the nationwide petrochemical industries in which small and medium sized companies are in mutual and intimate cooperation. The results show that the business structure of the petrochemical industries are divided into four stages, and, with the introduction of e-business, the value chain is changed by stages. And the change of value-chain explains the transition of the e-business of petrochemical industries including trade business into industrial DB and leads to a variety of the economic effect including the reduction in the trade expense, the change of the production process, and the innovation of trade structure.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.2242-2249
• /
• 2008

A severe problem in VE study of a project is to reduce value due to loss of performance, caused by focusing on cost reduction. Also a lack of understanding performance concept, no trial VE workshop as well as cost saving-based policy have not satisfied customer needs. A efficient VE job plan for especially large scale railroad construction project is proposed in this study. This study developed a more objective performance evaluation system for value engineering study of mega projects and suggested a systematic process of performance quantitative analysis for value improvement. The proposed performance measurement method would be very useful for better communication and consensus between decision makers and VE team.

• 한국디자인학회:학술대회논문집
• /
• 한국디자인학회 2005년도 추계 학술발표대회 논문집
• /
• pp.160-161
• /
• 2005

• 한국디자인학회:학술대회논문집
• /
• 한국디자인학회 2005년도 춘계 학술발표대회 논문집
• /
• pp.150-151
• /
• 2005