• Educational Technology International
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• v.21 no.2
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• pp.125-153
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• 2020

The advancement of virtual reality technology offers various locomotion options that support users' navigation behaviors in a virtual reality environment. This study was aimed at examining the effects of two navigation methods-joystick-controlling and walking-around-on users' perceived usability, behavioral engagement, and virtual presence. Fifty South Korean college students were recruited in the study, and they were assigned randomly to one of the two navigation conditions. Participants from each group were asked to observe a 3D object and complete the surveys. They were then asked to repeat the procedure with a 2D image. Using repeated-measures ANOVAs and MANOVA, we found that users using joystick-controlling reported higher usability and showed superior performance to the walking-around group on two tasks. Participants reported a higher behavioral engagement when observing the 2D image. Besides, they perceived a significantly higher virtual presence when observing the 2D image. Finally, we discussed the implications of the findings for the navigation method design.

• International Journal of Contents
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• v.18 no.3
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• pp.1-10
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• 2022

The advancement of Internet technologies has provided a new and effective way to cultivate international talents. To investigate the effect of native English teachers' online synchronous classes on Chinese primary school students' oral English improvement, an 18-month quasi-experimental study was conducted on 300 primary school students in China. The experiment and control groups were provided biweekly synchronous online classes with native and non-native English teachers. SPSS was used to conduct Paired Sample T-Tests and analyze performance differentials. The results showed that online classes taught by native English teachers perform better than non-native English teachers in three areas: vocabulary accuracy, average sentence length, and phonological intonation.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.38-50
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• 2023

Proton exchange membrane fuel cell (PEMFC) is a portable and clean power generation device. The structural arrangement of the flow field has a significant influence on the delivery efficiency of PEMFC. In this article, a new bionic flow channel is designed based on the inspiration of a spider shape. The branch channel width and branch corner are studied as the focus, and its simulation is carried out by the method of computational fluid dynamics (CFD). The results show that when channel width/rib width and corner of the branch are 1.5 and 130° , respectively, it is the best numerical combination and the cell comprehensive performance is excellent. The final model using this numerical combination is compared with the traditional flow channel model to verify the advancement of this scheme.

• Structural Engineering and Mechanics
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• v.86 no.2
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• pp.211-220
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• 2023

The textile industry has benefited from nanotechnology in various fields of application as the use of nanomaterials, and nanotechnology is multiplying. Nanoparticles can increase the performance of textiles by up to 100 times when used in finishing, coating, and dyeing techniques, providing them with capabilities they did not previously possess. Nanotechnology is used in the textile chemical industry to produce sports mats with stain resistance, flame resistance, wrinkle resistance, moisture management, antimicrobial quality, and UV protection. The incorporation of nanomaterials into fabrics can have a significant effect on their properties, including shrinkage, strength, electrical conductivity, and flammability. Various inventions and innovations may result from nano-processed textiles in the future, thus leading to the advancement of science. This article presents the construction of sports engineering structures with high resistance to improve the quality of sports training. The mechanical properties of sports mats are improved with the help of nanotechnology. Strength, elasticity, and tear resistance are among these properties. This method enables the production of elastic, durable, and tear-resistant sports mats.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.164-168
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• 2023

Accurate and reliable weather forecasts for temperature, relative humidity, and precipitation using advanced transformer models and IoT are essential in various fields related to global climate change. We propose a novel weather prediction device that integrates state-of-the-art transformer models and IoT techniques to improve prediction accuracy and real-time processing. The proposed system demonstrated high reliability and performance, offering valuable insights for industries and sectors that rely on accurate weather information, including agriculture, transportation, and emergency response planning. The integration of transformer models with the IoT signifies a substantial advancement in weather and climate modeling.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.spc
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• pp.68-78
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• 2023

Big data technology is being used in various fields followed by the development of information and communication technology. In the corporate and public sectors, diverse system platforms are built and operated due to the needs of users, but efficiency is low because they are built from an individual service perspective rather than an integrated service perspective. In this study, the relationship between presenting the characteristics of the type of shared information platform, the integration plan, and integration performance of the shared information system platform was analyzed. The results of the study will provide guidelines for the integration of shared information system platforms by the government and private companies in the future.

• ETRI Journal
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• v.45 no.5
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• pp.746-757
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• 2023

This study presents a novel safe landing algorithm for urban drone deliveries. The rapid advancement of drone technology has given rise to various delivery services for everyday necessities and emergency relief efforts. However, the reliability of drone delivery technology is still insufficient for application in urban environments. The proposed approach uses the "landing angle control" method to allow the drone to land vertically and a rapidly exploring random tree-based collision avoidance algorithm to generate safe and efficient vertical landing paths for drones while avoiding common urban obstacles like trees, street lights, utility poles, and wires; these methods allow for precise and reliable urban drone delivery. We verified the approach within a Gazebo simulation operated through ROS using a six-degree-of-freedom drone model and sensors with similar specifications to actual models. The performance of the algorithms was tested in various scenarios by comparing it with that of stateof-the-art 3D path planning algorithms.

• Current Optics and Photonics
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• v.8 no.1
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• pp.1-15
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• 2024

This paper presents a brief introduction to self-interference incoherent digital holography (SIDH). Holography conducted under incoherent light conditions has various advantages over digital holography performed with a conventional coherent light source. We categorize the methods for SIDH, which divides the incident light into two waves and modulates them differently. We also explore various optical concepts and techniques for the implementation and advancement of SIDH. This review presents the system design, performance analysis, and improvement of SIDH, as well as recent applications of SIDH, including optical sectioning and deep-learning-based SIDH.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.48-55
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• 2024

Metal-oxide-based semiconductor gas sensors are widely used because of their advantages, such as high response and simple sensing mechanism. Recently, with the rapid progress in sensor networks, computing power, and microsystem technology, sensor applications are expanding to various fields, such as food quality control, environmental monitoring, healthcare, and artificial olfaction. Therefore, the development of highly selective gas sensors is crucial for practical applications. This article reviews the developments in novel sensor design consisting of sensing films and physical and chemical filters for highly selective gas sensing. Unlike conventional sensors, the sensor structures with filters can separate the sensing and catalytic reactions into independent processes, enabling selective and sensitive gas sensing. The main objectives of this study are directed at introducing the role of various filters in gas-sensing reactions and promising sensor applications. The highly selective gas sensors combined with a functional filter can open new pathways toward the advancement of high-performance gas sensors and electronic noses.

• Animal Bioscience
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• v.37 no.2_spc
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• pp.385-395
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• 2024

Ruminal ciliates are a fundamental constituent within the rumen microbiome of ruminant animals. The complex interactions between ruminal ciliates and other microbial guilds within the rumen ecosystems are of paramount importance for facilitating the digestion and fermentation processes of ingested feed components. This review underscores the significance of ruminal ciliates by exploring their impact on key factors, such as methane production, nitrogen utilization efficiency, feed efficiency, and other animal performance measurements. Various methods are employed in the study of ruminal ciliates including culture techniques and molecular approaches. This review highlights the pressing need for further investigations to discern the distinct roles of various ciliate species, particularly relating to methane mitigation and the enhancement of nitrogen utilization efficiency. The promotion of establishing robust reference databases tailored specifically to ruminal ciliates is encouraged, alongside the utilization of genomics and transcriptomics that can highlight their functional contributions to the rumen microbiome. Collectively, the progressive advancement in knowledge concerning ruminal ciliates and their inherent biological significance will be helpful in the pursuit of optimizing rumen functionality and refining animal production outcomes.