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        검색결과 1,166

        1.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper addresses a scheduling problem aimed at minimizing makespan in a permutation flow shop with two machines and an inspection process that must be conducted at least once every certain number of outcomes from the first machine. A mathematical programming approach and a genetic algorithm, incorporating Johnson's rule and a specific mutation process, were developed to solve this problem. Johnson's rule was used to generate an initial population, while the mutation process ensured compliance with the inspection constraints. The results showed that within a computation time limit of 300 seconds, the mathematical programming approach often failed to provide optimal or feasible solutions, especially for larger job sets. For instance, when the process times of both machines were similar and the inspection time was longer, the mathematical programming approach failed to solve all 10 experiments with just 15 jobs and only had a 50% success rate for 100 jobs. In contrast, the proposed genetic algorithm solved all instances and delivered equal or superior results compared to the mathematical programming approach.
        4,000원
        2.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lumpy Skin Disease (LSD) and Foot-and-Mouth Disease (FMD) cause substantial economic losses on the livestock industry. Therefore, vaccinations have been implemented as the control strategy in endemic countries. However, the potential adverse effects of administering vaccines for both diseases simultaneously have not been thoroughly evaluated. The aim of this study was to assess the impact of vaccinating dairy cows with either or both LSD and FMD vaccines on milk production and physiological parameters such as milk temperature, rumination time and body weight. The experimental groups were divided into four according to the injection materials: 1) saline, 2) LSD vaccine, 3) FMD vaccine, and 4) both vaccines. The impact of vaccination on milk yield and physiological parameters was evaluated daily until 12 days post-vaccination, and milk components were analyzed twice, once per week. Among the experimental groups as well as each vaccine group, no statistically significant differences (p < 0.05) were observed at milk yield, milk components, or milk temperature. This suggests that simultaneous vaccination of LSD and FMD can be administered without adverse effects.
        4,000원
        3.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study seeks to explore how key restaurant attributes differently influence customer satisfaction and dissatisfaction across pre-pandemic and post-pandemic periods, as well as across various economic segments. By employing impact asymmetry analysis (IAA), the research identifies the primary drivers of customer satisfaction and dissatisfaction, examining their uneven on customer satisfaction in Korean restaurants. The findings underscore the non-linear and asymmetric nature of customer responses to various service attributes, highlighting the significant influence of economic factors and the pandemic on dining expectations and experiences. This research deepens our understanding of the factors shaping customer satisfaction dynamics, particularly in the context of the evolving post-pandemic restaurant industry.
        4,000원
        4.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Maturity at harvest is the key factor influencing storage life and the final quality of fruit. This study examined how the firmness of ‘Sweet Gold’ kiwifruit at harvest affects its post-ripening characteristics to create a maturity chart. Throughout the storage period, firmness decreased in all categories of fruit: hard, medium, and soft. ‘Soft’ fruits lost 40% of their firmness within 2 days after harvest, whereas ‘hard’ fruits remained firmer than soft fruits throughout the storage period and had the least soluble solids content, indicating a slower ripening progression. The acidity of ‘soft’ kiwifruit was very low from the day of harvest, suggesting that it was utilized as a respiratory substrate during ripening. The a-values (indicating redness) for ‘soft’ fruits gradually increased until day 6, stabilizing thereafter. ‘Soft’ fruits exhibited the highest ethylene production rate throughout storage. They showed a climacteric rise in ethylene on day 13, compared to ‘medium’ and ‘hard’ fruits, which exhibited increases on days 19 and 21, respectively. This data can help determine the optimal ethylene treatment duration for ripening ‘Sweet Gold’ kiwifruit. The firmness of ‘Sweet Gold’ kiwifruit at harvest is a crucial factor in determining its marketability and can effectively serve as a maturity index to estimate its shelf life.
        4,000원
        5.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 절화 국화의 수경재배와 토경관비재배 시 생육 특 성을 비교하기 위하여 실시하였다. 그 결과 초장, 절화의 생체중 과 건물중은 토경관비재배에서 증가하였다. 식물체 내 전질소, 칼륨 및 칼슘의 함량도 토경관비재배에서 더 높았다. 반면에 줄기 직경은 수경재배에서 3.7mm로 증가하였다. 또한 개화소 요일수도 토경관비재배보다 수경재배에서 3일 정도 단축되었 고, 줄기 1개당 꽃 수도 19.6개로 수경재배에서 더 많았다. 결과 적으로 토경관비재배에서 식물체 내 무기염류 함량이 높고, 초장이 길어지고 생체중, 건물중이 증가하였지만 수경재배보다 개화기는 지연되었다. 또한 토경관비재배보다 수경재배에서 줄 기 직경이나 꽃 수 등이 증가하였다. 따라서 재배자의 입장에서 국화 수경재배를 통해 양분과 수분 공급량의 조절에 의한 개화 기의 조절, 조기 개화 및 절화 품질 향상 등의 효과를 기대할 수 있을 것으로 판단된다.
        4,000원
        6.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined consumer perceptions and market trends of Korean food products sold on Amazon, focusing on keyword and review analysis. As Korean cuisine gains global attention, particularly in the U.S., it is essential to understand how international consumers perceive these products. Data were collected from Amazon, encompassing product details and customer reviews of Korean food categories. Frequently mentioned keywords in the reviews were identified, and customer sentiments were explored using Python-based data analysis. The results suggest that taste, especially spiciness and sweetness, is a key determinant of consumer satisfaction. Although Korean food was generally well-received, packaging and delivery issues were common complaints. These findings provide strategic insights for Korean food manufacturers aiming to expand globally, emphasizing the need for tailored product development and enhanced logistics.
        4,000원
        7.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 페튜니아(Petunia×hybrida)의 내건성 증진을 위 해 스트레스 메모리 기작을 활용한 프라이밍 처리의 효과를 구명 하고자 하였다. 건조-회복 과정을 통한 프라이밍 처리를 4회 반복 수행하였고, 두 가지 프라이밍 강도(Priming1:물 100mL, Priming2: 물 50mL 관수 후 건조)를 적용한 후 5일 동안 건조스 트레스 조건에서 내성 증진 효과를 관찰하였다. 프라이밍 강도가 높은 Priming2 처리구에서 대조군에 비해 수명이 약 25시간 연장되었다. 이는 페튜니아가 스트레스 메모리 기작을 통해 건조 스트레스에 대한 내성을 높일 수 있음을 보여준다. 본 연구는 정원 식물의 환경 스트레스 내성을 증진시키기 위한 프라이밍 기술의 유용성을 확인하였으며, 향후 다양한 환경 스트레스 조건 에서의 프라이밍 효과를 평가함으로써 화훼식물의 내건성 증진 에 대한 실용적 기술 개발에 기여할 수 있을 것으로 기대된다.
        3,000원
        8.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the depth of the interphase in graphene polymer systems is determined by the properties of graphene and interfacial parameters. Furthermore, the actual volume fraction and percolation onset of the nanosheets are characterized by the actual inverse aspect ratio, interphase depth, and tunneling distance. In addition, the dimensions of graphene, along with interfacial/interphase properties and tunneling characteristics, are utilized to develop the power-law equation for the conductivity of graphene-filled composites. Using the derived equations, the interphase depth, percolation onset, and nanocomposite conductivity are graphed against various ranges of the aforementioned factors. Moreover, numerous experimental data points for percolation onset and conductivity are presented to validate the equations. The optimal levels for interphase depth, percolation onset, and conductivity are achieved through high interfacial conductivity and large graphene nanosheets. In addition, increased nanocomposite conductivity can be attained with thinner nanosheets, a larger tunneling distance, and a thicker interphase. The calculations highlight the considerable impacts of interfacial/interphase factors and tunneling distance on the percolation onset. The highest nanocomposite conductivity of 0.008 S/m is acquired by the highest interfacial conduction of 900 S/m and graphene length (D) of 5 μm, while an insulated sample is observed at D < 1.2 μm. Therefore, higher interfacial conduction and larger nanosheets cause the higher nanocomposite conductivity, but the short nanosheets cannot promote the conductivity.
        4,200원
        9.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The AlSi10Mg alloy has garnered significant attention for its application in laser powder bed fusion (L-PBF), due to its lightweight properties and good printability using L-PBF. However, the low production speed of the L-PBF process is the main bottleneck in the industrial commercialization of L-PBF AlSi10Mg alloy parts. Furthermore, while L-PBF AlSi10Mg alloy exhibits excellent mechanical properties, the properties are often over-specified compared to the target properties of parts traditionally fabricated by casting. To accelerate production speed in L-PBF, this study investigated the effects of process parameters on the build rate and mechanical properties of the AlSi10Mg alloy. Guidelines are proposed for high-speed additive manufacturing of the AlSi10Mg alloy for use in automotive parts. The results show a significant increase in the build rate, exceeding the conventional build rate by a factor of 3.6 times or more, while the L-PBF AlSi10Mg alloy met the specifications for automotive prototype parts. This strategy can be expected to offer significant cost advantages while maintaining acceptable mechanical properties of topology-optimized parts used in the automobile industry.
        4,000원
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