Earticle

Virtual Reality (VR) has been widely used in various applications to generate realistic virtual environments. A sense of immersion can be increased by providing additional stimuli such as tactile sensation to VR contents. However, it is still challenging to provide a realistic feel for the wind blowing over the whole body by smoothly controlling the airflow. To address this issue, we employ a household electric fan as a wind generating device to provide users with wind experience in VR environments. The wind generating device targets the whole body to mimic the wind we feel outside in our daily life. To do so, we present a low-cost method to smoothly control household fan speed using an Arduino microcontroller. Here, we use the Sinusoidal Pulse Width Modulation (SPWM) technique to generate the sinusoidal voltage required to drive the fan motor. Our experimental results show how Variable Voltage Variable Frequency (VVVF) is implemented at a low cost using our method for household fan speed control. The results can be applied to various VR applications to enhance the sense of immersion by providing users with realistic wind.

The purpose of this study is to identify the factors that influence the revisit of jewelry stores. The purpose od this study is to find specific factors that affect product and store satisfaction. The theoretical studies on product quality, perceived quality guarantee, product design, product price, sales promotion, product diversity, store area, store re-visit intent were reviewed. Based on this background, research hypotheses were established. A total of 80 questionnaires were distributed to verify the hypothesis of the study, and 64 were finally used for the analysis. SPSS 24.0 was used for hypothesis verification. The results of this study showed that product quality, perceived product guarantee, product design, and product price had positive influence on product satisfaction. On the other hand, sales promotion, product diversity and store interior were found to have positive influence on store satisfaction. Furthermore, product and store satisfaction were found to have a positive and significant effect on revisit Jewelry Stores.

A society will lose a lot of something in this field when the forest fire broke out. If a forest fire can be detected in advance, damage caused by the spread of forest fires can be prevented early. So, we studied how to detect forest fires using CCTV currently installed. In this paper, we present a deep learning-based model through efficient image data construction for monitoring forest fire smoke, which is unstructured data, based on the deep learning model YOLOv5. Through this study, we conducted a study to accurately detect forest fire smoke, one of the amorphous objects of various forms, in YOLOv5. In this paper, we introduce a method of self-learning by producing insufficient data on its own to increase accuracy for unstructured object recognition. The method presented in this paper constructs a dataset with a fixed labelling position for images containing objects that can be extracted from the original image, through the original image and a model that learned from it. In addition, by training the deep learning model, the performance(mAP) was improved, and the errors occurred by detecting objects other than the learning object were reduced, compared to the model in which only the original image was learned.

Due to the expansion of non-face-to-face services, the demand for user identification for mobile devices is increasing. Recently, mobile resident registration cards, mobile driver's licenses, etc. are installed in mobile phones and used for user identification and authentication services. In order to identify a user online, unique identification information of the online user is required. In particular, in order to provide information only to online users, it is necessary to accurately deliver information to a mobile device owned by the user. To make this service possible, it was realized with the advent of mobile electronic notice service. However, the identification of online service users and information on mobile devices owned or subscribed by the relevant users require safe management as personal information, and it is also necessary to increase the convenience of online service users. In this paper, we propose an operating standard for providing a mobile electronic notice service that sends electronic notice using a mobile device owned by the user. The mobile electronic notice service is a service that provides notices expressed in electronic information to the recipient's cell phone, mobile app, e-mail, etc. Therefore, as the use of mobile electronic notification service increases and the provision and use of connecting information to identify users increases, it is necessary to expand the mobile electronic notification service while safely protecting users' personal information.

In this study, the insertion loss and phase delay according to the multi-layer structure radome parameters were analyzed using the boundary value solution approach, and the multi-layer structure and hexa mesh structures with low-loss electrical characteristics for the Ku-band transmission/reception frequency of 10.7 ~ 14.5 GHz were designed and manufactured. A hexa mesh was applied to minimize radio wave transmission and scattering, which lowered the transmittance refractive index according to the radio incident angle and minimized dielectric loss through high-density foam. Similar to the simulation result, the transmission loss obtained the gain in a specific receiving frequency band, and in the transmission frequency band, an excellent low loss characteristic was obtained with an insertion loss of 0.8dB or less. The results of this study can be used in radio transmission radomes of low-weight, low-cost end-system protection devices.

This study investigated how pre-service English teachers perceive the effects of machine teaching on their English writing competence. 35 Korean students who are majoring in English education participated in this study. The participants used machine translators for one of the required courses related to English composition. A survey and focus group interview were conducted at the end of the course. They were asked to answer to what degree they perceive the effects of machine translators on their writing in terms of lexical, sentential, and discourse levels. Furthermore, their perspectives on the effects of machine translation on English teaching including limitations of machine translators, were interviewed in more detail. The results show that the participants perceive machine translators quite positively in terms of improving their writing competence, but they also point out some critical limitations of machine translators. These findings have some pedagogical implications for English writing course instructors, English teacher educators, and program developers.

This is a research thesis on the development of a monitoring and diagnosis device that prevents the risk of an accident through monitoring and diagnosis of a modular Main Circuit Breaker (MCB) using Vacuum Interrupter (VI) for Korean high-speed rolling stock. In this paper, a comprehensive MCB monitoring and diagnosis was performed by converging vacuum level diagnosis of interrupter, operating coil monitoring of MCB and environmental temperature/humidity monitoring of modular box. In addition, to develop an algorithm that is expected to have a similar data processing before the actual field test of the MCB monitoring and diagnosis device in 2023, the cluster analysis and factor analysis were performed using the WEKA data mining technique on the big data of Korean railroad transformer, which was previously researched by Tae Hee Evolution with KORAIL.

In this paper, we discuss the relative positioning of Wh-related English prepositions in a Wh-interrogative construction within the Optimality Theory [1-2]. By employing the two key constraints such as *Prep-Str and Align which are developed for the positioning of Wh-related prepositions from Romance languages such as French and Italian [3] and for the positioning of Wh-related prepositions from the middle English prose from 1500 to 1900 [4-6], and by slightly modifying the constraint hierarchy of *Prep-STR >>Align into **Prep-STR <<>>Align, Choi argues that his new theory can properly explain the unique behaviors of English Wh-related prepositions being able to take two ‘optional’ operations such as pied-piping and stranding to find legitimate landing sites in a Wh-interrogative construction [7]. However, this new analysis again reveals the following critical problems: (1) Unlike the ‘light’ English Wh-related prepositions which can two optional operations for legitimate landing sites in a Wh-interrogative construction, ‘heavy’ Wh-related English prepositions are not allowed to have such two options: they take just one option of pied-piping only. Thus, (2) his argumentation based on the existing constraints and the modified constraint hierarchy is neither general enough nor proper to explain the issue of the relative positioning for all English Wh-related preposition cases. To include such exceptional syntactic property of the ‘heavy’ preposition cases within the Optimality Theory, we suggest a new constraint of *HPrep-STR ranked at the highest position of the constraint hierarchy to disallow a ‘heavy’ or multi-syllabic Wh-related English preposition to stay alone at the end of a sentence. The new final hierarchy of constraints we suggest to explain the exceptional positioning of ‘heavy’ Wh-related prepositions together with the other ‘light’ Wh-related prepositions in English Wh-interrogative construction will be as follows: *HPrep-STR>>Align<<>>*Prep-STR.