최근 인터넷은 데이터와 사람, 사물을 연결할 뿐만 아니라 장소와 저작권을 상호 연결하기 시작했다. 실제 로 현실과 가상세계의 경계가 사용자가 더 이상 알아차릴 수 없을 정도로 점점 희미해지고 있다. 사람들이 일상생활을 가상으로 수행할 수 있기 때문에 현실 세계의 경험은 더 이상 불필요 할지도 모른다. 본 논문은 메타버스의 기본 개념 및 기술의 심층적인 이해를 제공하는 것을 목적으로 메타버스의 발전에 대한 연구를 진행하였다. 현재 가장 대표적인 메타버스 플랫폼에 대한 설명과 분석을 통해 메타버스의 장점, 단점, 유저 와 메타버스 플랫폼 사업자가 해결해야 할 문제점에 대해서 연구하였다. 본 논문은 메타버스의 발전과 함께 메타버스가 해결해야할 문제와 기회 그리고 메타버스의 미래에 대해 연구를 목표로 한다.

An automated material handling system (AMHS) has been emerging as an important factor in the semiconductor wafer manufacturing industry. In general, an automated guided vehicle (AGV) in the Fab’s AMHS travels hundreds of miles on guided paths to transport a lot through hundreds of operations. The AMHS aims to transfer wafers while ensuring a short delivery time and high operational reliability. Many linear and analytic approaches have evaluated and improved the performance of the AMHS under a deterministic environment. However, the analytic approaches cannot consider a non-linear, non-convex, and black-box performance measurement of the AMHS owing to the AMHS’s complexity and uncertainty. Unexpected vehicle congestion increases the delivery time and deteriorates the Fab’s production efficiency. In this study, we propose a Q-Learning based dynamic routing algorithm considering vehicle congestion to reduce the delivery time. The proposed algorithm captures time-variant vehicle traffic and decreases vehicle congestion. Through simulation experiments, we confirm that the proposed algorithm finds an efficient path for the vehicles compared to benchmark algorithms with a reduced mean and decreased standard deviation of the delivery time in the Fab’s AMHS.

On October 22, 2021, the Ministry of Commerce of the People’s Republic of China (PRC) promulgated the Development Plan for the Utilization of Foreign Capital during the 14th Five-Year Period. The plan has attracted wide attention from investors and scholars at home and abroad. The global economic recovery is full of unpredictable challenges due to the spread of Covid-19, so absorbing foreign investment is critical to the economic development in most countries. The plan was based on the 14th Five-Year Plan for National Economic and Social Development and the Outline of Long-term Objectives for 2035. China is changing the direction of attracting investment from manufacturing industry to service industry. This article discusses China’s current utilization of foreign capital and analyzes the newly promulgated plan, including its key features, overall objectives, and basic tasks. It also examines the opportunities and challenges China faces in its future utilization of foreign capital.

This study explored the possibility of forming a coating layer containing alginic acid on the surface of a magnesium alloy to be used as a biomaterial. We formed a coating layer on the surface of a magnesium alloy using a plasma electrolytic oxidation process in an electrolytic solution with different amounts of alginic acid (0 g/L ~ 8 g/L). The surface morphology of all samples was observed, and craters and nodules typical of the PEO process were formed. The cross-sectional shape of the samples confirmed that the thickness of the coating layer became thicker as the alginic acid concentration increased. It was confirmed that the thickness and hardness of the sample significantly increase with increasing alginic acid concentration. The porosity of the surface and cross section tended to decrease as the alginic acid concentration increased. The XRD patterns of all samples revealed the formation of MgO, Mg2SiO4, and MgF2 complex phases. Polarization tests were conducted in a Stimulate Body Fluid solution similar to the body's plasma. We found that a high amount of alginic acid concentration in the electrolyte improved the degree of corrosion resistance of the coating layer.

This investigation aimed to assess the appetite response changes of olive flounder to starving and re-feeding conditions. Three different feeding groups (2 weeks feeding, fed; 2 weeks starving, starved; and 1 week starving and 1 week feeding, re-fed) were established to examine the changes in appetite-related genes for each group. The weight gain of the fish was highest for the fed group and lowest for the starving group. Based on the daily feed intake (DFI) and cumulative feed intake (CFI), overall food intake was found to increase in the re-fed group more than in the fed group from week 1 to week 2 of the experiment. Hypocretin neuropeptide precursor (HCRT) and galanin receptor 1 (GAL-R1) mRNA expression in the brain of olive flounder were decreased in the starved group. Corticotropin-releasing hormone (CRH) was decreased in all experimental groups, except for the fed group. However, overall leptin concentrations in the plasma did not change across groups. Considering the differences between this study and previous studies on starving and feeding, various factors (except the production and expression mechanisms of appetite-related factors in response to starving) are likely acting on the appetite responses of the fish. In this study, a 1-week re-feeding period induced substantial effects on appetite response when compared to a 2-week feeding period. These findings show that even if re-feeding is performed after starving, the unbalance caused by the re-feeding can affect various physiological changes in fish by feed intake efficiency.