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.
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.
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.
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.
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.
최근 딥러닝은 자기공명영상 검사에서의 화질 개선을 위해 다양하게 활용되고 있다. 하지만 다양한 자기공명영상 검사에서 딥러닝이 적용된 기법과 상황에 대한 평가는 부족한 편이다. 이에 본 연구에서는 모션 ACR(American College of Radiology) 팬텀을 활용하여 일반적인 상황과 움직이는 상황에서 T2-PROPELLER(periodically, rotated overlapping parallel lines with enhanced reconstruction, PROPELLER)와 T2-FSE(fast spin echo, FSE) 기법의 화질을 비교 평가해 보고자 하였다. 연구 결과 움직이지 않는 상황에서의 딥러닝 프로세스를 적용하였을 때 유의미한 신호대잡음비와 대조대잡음비의 상승을 보였다. 하지만 팬텀에 움직임을 주는 동적인 상황 에서 딥러닝 프로세스를 적용하였을 때 유의미한 화질 개선을 보이지 않았다. 이러한 결과는 딥러닝 프로세스를 절대 적으로 사용하기보다 다양한 상황에 맞게 선택적으로 적용하는 것이 필요할 것으로 사료된다.
Inflammatory bowel disease (IBD) is a chronic condition characterized by continuous inflammation of the gastrointestinal tract that varies in intensity over time. IBD is caused by several factors including aberrant gut flora, immunological dysregulation, altered environmental conditions, and genetic variations. However, the pathogenesis of IBD remains unclear. Studies have indicated that an imbalance between T helper 17 (Th17) and regulatory T (Treg) cells contributes significantly to the development of IBD. Intestinal Tregs suppress inflammation and are critical for maintaining tissue homeostasis. Th17 cells are known to play an important role in the development and pathogenesis of IBD and provide non-inflammatory support for the integrity of the intestinal barrier against bacterial and fungal infections. Therefore, the Th17/Treg cell balance is crucial in the pathogenesis of IBD and gut integrity. The microenvironment of the intestinal mucosal immunity is regulated by the secretion of cytokines associated with Th17 cells and Tregs. Several studies have indicated that the gut bacteria contribute to the control of the immune milieu and play a key role in the regulation of Th17 cell development. Intestinal bacteria and cytokines control Th17 cell development. Th17 cells secrete cytokines that regulate the immune microenvironment in the gut mucosa. This review provides an overview of Th17 cells and examines the strategies for treating patients with IBD using Th17 cell-targeted drugs.
The Korea Forest Service has designated seven alpine tree species—Abies koreana, A. nephrolepis, Juniperus chinensis, Picea jezoensis, Pinus pumila, Taxus cuspidata, and Thuja koraiensis—as threatened with extinction in Korea. In 2023, we conducted a study on the seasonal occurrence of insect pests, focusing mainly on two coleopteran taxa (Cerambycidae and Scolytinae) and two hemipteran taxa (Aphrophoridae and Cicadellidae) in subalpine forests dominated by A. koreana, A. nephrolepis, Picea jezoensis, Thuja koraiensis, and Taxus cuspidata. We utilized three types of traps—Malaise trap, Lindgren funnel trap, and window trap—in eight investigation locations in Korea. In this presentation, we present the study results and discuss the effects of insect pests on alpine coniferous trees in Korea.
Animal experiments have demonstrated the effectiveness of fermented rice germ and soybean extracts in lowering blood alcohol concentration. A compound primarily derived from fermented soybean extract constitutes the principal component of DA-5521, an experimental dietary substance examined in this study. We investigated the possible hangover-alleviating effects of DA-5521 in individuals aged 19 to 50 who had previously experienced hangovers. Moreover, we enrolled 22 participants who met the eligibility criteria and conducted a double-blind, randomized, placebo-controlled crossover trial. Six hours after alcohol consumption, the test group exhibited a statistically significant reduction in blood acetaldehyde concentration compared with the placebo group. Further, our results displayed significantly lower levels in the DA- 5521 group at 0.50 and 0.75 h post-ingestion and substantially lower peak breath alcohol concentration compared to the placebo group. These findings confirm that consumption of DA-5521 can significantly ameliorate hangover symptoms by diminishing blood acetaldehyde concentration and reduce breath alcohol concentration.
Korean historical literatures offer numerous records on astronomical phenomena such as eclipses, comets, and close approaches, etc. Records of close approaches often use specific terms to describe the angular distance, which lack translation into modern numerical values. We study the usage of the five commonly used terms, namely, Entry (入, En), Invasion (犯, In), Occultation (掩, Oc), Eclipse (食, Ec), as well as the unit Chi (尺). Our analysis is based on more than 2,300 records from Goryeo (918–1392 CE) and Joseon (1392–1910 CE) Dynasties. Through statistical analysis, we determine their quantitative definitions. We convert the lunisolar calendar to the Julian and Gregorian date and utilize the modern ephemeris DE431 to calculate the angular distance between celestial bodies. We find that the angular distances of the terms En, In, Oc, and Ec correspond to respectively 1.78◦+2.36 −1.11, 0.89◦+3.54 −0.51, 0.44◦+1.15 −0.31, and 0.29◦+2.61 −0.16 for the Goryeo Dynasty and 1.36◦+1.15 −0.64, 0.51◦+1.11 −0.32, 0.25◦+0.27 −0.17, and 0.21◦+0.25 −0.11 for the Joseon Dynasty. Additionally, we determine the angular size of the unit Chi by using the records from Korean chronicles along with the drawings of comets’ tails in the Daily Log (天變謄錄). We estimate the unit Chi to be 1.11◦+0.46 −0.40 and find that the numerical definition was consistent throughout the two dynasties in Korea. Furthermore, we find that the terms were used to describe the closest approach and that there is no observational bias in the angular distances against the apparent magnitudes of the objects. We show that the terms En, In, Oc, and Ec represent decreasing angular distance in that order and this ordering was consistent in both dynasties.
In recent times, there has been a significant demand for supercapacitors in energy storage applications due to their rapid charging– discharging capabilities, high power density, and excellent stability. Nevertheless, the synthesis of electrode materials with a substantial surface area, exceptionally high porosity, and superior electrochemical performance is still challenging. Activated carbons with a distinctive porous structure and exceptional electrochemical properties emerged as promising electrode materials for supercapacitors. In this study, we used a porous activated carbon (PAC) derived from petroleum coke followed by KOH activation as an efficient anodic electrode material. The ultra-high Brunauer–Emmett–Teller surface area of 2105.6 m2 g− 1 with stacked layers of carbon atoms arranged in a two-dimensional hexagonal structure makes the PAC an efficient candidate for a supercapacitor electrode. The PAC delivers a specific capacitance of 470 F g− 1 at a current density of 0.5 A g− 1 over a potential window of 0 to −1 V. The excellent cycling stability in a three-electrode setup with a capacitance retention of ⁓98% even at a high current density of 10 A g− 1 makes the PAC a potential anodic electrode material for high-performance supercapacitor applications.