Bearing-shaft systems are essential components in various automated manufacturing processes, primarily designed for the efficient rotation of a main shaft by a motor. Accurate fault detection is critical for operating manufacturing processes, yet challenges remain in sensor selection and optimization regarding types, locations, and positioning. Sound signals present a viable solution for fault detection, as microphones can capture mechanical sounds from remote locations and have been traditionally employed for monitoring machine health. However, recordings in real industrial environments always contain non-negligible ambient noise, which hampers effective fault detection. Utilizing a high-performance microphone for noise cancellation can be cost-prohibitive and impractical in actual manufacturing sites, therefore to address these challenges, we proposed a convolution neural network-based methodology for fault detection that analyzes the mechanical sounds generated from the bearing-shaft system in the form of Log-mel spectrograms. To mitigate the impact of environmental noise in recordings made with commercial microphones, we also developed a denoising autoencoder that operates without requiring any expert knowledge of the system. The proposed DAE-CNN model demonstrates high performance in fault detection regardless of whether environmental noise is included(98.1%) or not(100%). It indicates that the proposed methodology effectively preserves significant signal features while overcoming the negative influence of ambient noise present in the collected datasets in both fault detection and fault type classification.

본 연구는 자율주행상황에서 주관적인 운전 준비도를 객관적으로 측정할 수 있는 심리⋅생리적 지표를 확인하는 것을 목적으로 한다. 51명의 연구대상자가 참여하였고, 설문을 통해 운전 경험, 태도, 운전부하, 상황인식 등을 평가 하였다. 자율주행 중 차량 제어권을 인계받아야 하는 시나리오 동안 심전도를 측정하여 심박변이도 지표를 추출하였 고, 주행 종료 후 연구대상자는 자신의 상태를 평가하였다. 분석 결과, 운전 준비도는 정신적 부하와 부적 상관, 상황 인식과 상황 이해도와는 정적 상관을 보였다. 또한, 심박변이도 지표인 제곱 평균 근간 심박 간격 차이(Root Mean Square of Successive Differences, RMSSD)와 50ms 이상의 연속적인 RR 간격의 차이 비율(proportion derived NN50 by the total number of NN interval, pNN50)과의 유의한 정적 상관관계가 확인되었다. 운전 준비도 수준에 따라 상⋅중⋅하로 나누어 분석한 결과, 높은 운전 준비도 집단은 정신적 부하가 낮고 상황인식 및 상황에 대한 이해 도가 유의하게 높았으며, 자율주행 구간에서 pNN50이 높은 경향이 있었다. 마지막으로 상황인식과 RMSSD가 운전 준비도의 주요 예측 지표로 확인되었다. 이는 운전 준비도가 낮은 운전자는 자율신경 각성이 높고, 높은 운전자는 부교감신경계의 활성화로 인해 심리적, 생리적으로 안정된 상태임을 의미한다. 본 연구는 운전자의 주관적인 운전 준비도를 예측하기 위한 운전자의 심리 및 생리 지표를 확인하였고, 이는 운전자의 운전 준비 상태를 모니터링하는 기술에 적용되어 사고 예방에 기여할 수 있을 것이다.

Water lettuce (Pistia stratiotes L.) is a free-floating perennial herbaceous plant with rosette leaves and a stem. Although this plant multiplies and has adverse effects on aquatic ecosystems, it can be used for biological purification of polluted water and production of valuable substances as a traditional medicine. In this study, we report a protocol to establish an in vitro micropropagation method based on direct shoot organogenesis from stem explants. In media comprising two types of basal medium and different growth regulators, multiple shoot organogenesis was observed on stems. The micropropagation method was most effective on Schenk and Hildebrandt (SH) medium with 1 mg/L indole-3-acetic acid and 2 mg/L 6-benzylaminopurine supplemented with 30 g/L sucrose, on which all explants produced multiple shoots. The shoots rooted spontaneously on solid half-strength Murashige and Skoog (MS) and SH media without growth regulators (1/2MSO and 1/2SHO). However, roots developed more vigorously in liquid media. Regenerated plants colonized and grew more rapidly in SH basal medium than in MS basal medium and produced 6–8 stolons within 2 weeks on 1/2SHO. In summary, we established a method for micropropagation in vitro through direct organogenesis of water lettuce, which shows the potential of water lettuce as a model aquatic plant for phytochemical and pharmacological research.

This study investigated the effects of multisensory memory strategies of pairing visual and aural learning strategies of aural lexical advance organizers (LAO) and read-alouds on 146 Korean high school students learning the meaning and pronunciation of 18 unfamiliar English words. In this quasi-experimental design, the control group learned the words on a single mode of written LAO and silent reading as opposed to two treatment groups of aural LAO and silent reading, and of aural LAO and read-alouds, respectively. The effects were tested three times via pre-, post-(immediately after learning), and delayed (30 days later) tests. The immediate and long-term effects were examined by detecting the differences across the three groups in post- and delayed-tests by one-way ANOVA, and the retention of effects was examined by paired t-tests in each group across the three tests. The results indicated that pairing aural LAO and read-aloud strategies was most effective in learning and retention of both vocabulary meaning and pronunciation.

Although the proportion of coal-fired power generation is decreasing, efficient operating technology is needed to continuously invest in facilities and reduce maintenance costs until it is abolished. Boilers, one of the main facilities of power plants, operate for a long time in harsh environments of high temperature and high pressure. In addition, damage due to deterioration is likely to occur depending on the fuel and tube material used. It is very important to judge soundness because damage caused by deterioration adversely affects facility operation. Previously, replication method was used to analyze the progress of deterioration. In the replication method, pre-treatment such as chemical treatment is performed on the boiler tube in the field, the area is reproduced by attaching a film, and the replicated film is determined by an expert in the laboratory with an expensive microscope. However, this method involves substantial costs and time requirements, as well as the possibility of human errors. To address these issues, we developed a mobile health assessment system in this research. Since it is detachable and takes images in real time, this system enables swift evaluations across a broad range and facilitates the assessment of preprocessing quality. In addition, it was intended to reduce existing human mistakes by developing a degradation classification algorithm using the merger cluster method.

While social media marketing opens a variety of new windows for enlightening brand–customer relationships, a gritty puzzle is that brand recognition does not invariably echo with customers’ perceived value. This provokes the need to uncover the missing pieces in bridging the gap between brand recognition and customer perceived value. This research falls within the innovative new work in the marketing literature in positing co-creation as a crucial mediator in facilitating the impact of brand recognition on customers’ perceived value. Based on social identity theory, we also investigated how co-creation is moderated by virtual communication identification in influencing customers’ perceived value towards a brand. We conducted a survey via a sample of 386 current Gogoro customers. Gogoro is the biggest and most well-known Taiwanese producer of electric scooters. Our findings contribute to the extant marketing research by emphasizing that the key stimulus of increased customer perceived value towards a brand is active co-creation initiatives via virtual brand communities, and that the effects of co-creation are further strengthened when customers’ virtual communication identification is high.

To understand antioxidant enzyme response of two contrasting Arundinella hirta ecotypes to drought stress, drought-tolerant Youngduk and drought-sensitive Jinju-1, were comparatively analyzed changes in the enzymatic activities of peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR). Two ecotypes, drought-tolerant Youngduk and drought-sensitive Jinju-1 were subjected to drought stress by withholding water for 12 days. ROS accumulation level and electrolytic leakage were significantly increased in both A. hirta ecotypes by drought stress treatment but less in Youngduk than Jinju-1. The RWC significantly decreased in both the drought stress-treated ecotypes as compared to control, but less in Youngduk than Jinju-1. Soluble sugar and protein content were increased more in drought stress-treated Youngduk as compared to Jinju-1. The activities of antioxidant enzymes such as SOD, CAT, POD, APX, and GR increased significantly in both the drought stress-treated ecotypes Youngduk and Jinju-1 as compared to control. The increase in antioxidant enzyme activity level was more prominent in drought stress-treated Youngduk as compared to Jinju-1. Taken together, these results suggest that Youngduk was more tolerant to drought stress than Jinju-1, and seem to indicate that tolerance of A. hirta to drought stress is associated with increased activity of antioxidant enzymes.