• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.6
• /
• pp.807-812
• /
• 2021

In order to be able to interact with the user to experience it as if it were real in virtual reality contents, input/output devices that make them feel the five senses of humans are required . In virtual reality (VR), devices that stimulate sight and hearing are the most representative. For a more realistic experience, suits and gloves that stimulate the sense of touch have recently been released, but there are not many cases applied to actual contents due to the limitation of device . In this paper, we analyze a virtual reality glove that can detect hand movement and touch in a virtual world. Based on the analysis, we propose an algorithm that can sense the intensity of collision with a VR object by tactile sense by improving the UI/UX using the vibration of the feedback method used in the existing virtual reality glove. In addition, the system implemented by the algorithm is applied to an actual case.

• Journal of Convergence for Information Technology
• /
• v.12 no.1
• /
• pp.172-179
• /
• 2022

Unlike other processes such as washing, the ironing process in the laundry process is difficult to standardize and thus relies on manual labor. Unlike upper garments, pants have pleats at the waist as well as a crease line below the waist, Therefore, two separate ironing devices have been developed and used. However, in this method, problems such as additional worker input, space loss, and wrinkling of pants occur due to manual movement between processes, Consequently, a pants ironing device that combines the two equipments is required. The all-in-one pants ironing system described in this paper automatically sequentially irons the upper part and side of the pants regardless of the length, shape, and upper pleats of the pants. It also performs a self-diagnosis function while displaying the ironing progress on the user's monitor. As a result of this study, it became possible to double the amount of ironing and reduce power consumption by more than 20% compared to the case of using two independent equipment.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.6
• /
• pp.404-410
• /
• 2021

This paper proposes a high step-up converter with zero-voltage transition (ZVT) cell for fuel cell electric vehicle. The proposed converter applies a ZVT cell to a dual floating output boost converter (DFOBC) so that not only the main switch but also the ZVT switch can achieve full-range soft switching. The current rating of the ZVT switch is 17% of the main switch. The proposed converter has high reliability in that no timing issue occurs. Therefore, online calculation is not required. The minimum turn-on time of the ZVT switch that guarantees soft switching at all loads and input/output voltage is obtained by analysis. In addition, the proposed DFOBC allows the use of a 650 V device even at 800 V output and has the advantage of being able to boost the voltage by 3.5 times with 0.56 duty. Planar coupled inductor with PCB winding was successfully implemented with the converter operated at 300 kHz. The 25 kW prototype achieves peak efficiency of 99% and power density of 63 kW/L.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.1
• /
• pp.9-16
• /
• 2023

In the IoT environment, various objects mutually interactive, and various services can be composed based on this environment. In the previous study, we have developed a resource collaboration system to provide services by substituting limited resources in the user's personal device using resource collaboration. However, in the preceding system, when the number of resources and situations increases, the inference time increases exponentially. To solve this problem, this study proposes a method of classifying users and resources by applying the BIG5 user type classification model. In this paper, we propose a method to reduce the inference time by filtering the user's preferred resources through BIG5 type-based preprocessing and using the filtered resources as an input to the recommendation system. We implement the proposed method as a prototype system and show the validation of our approach through performance and user satisfaction evaluation.

• Journal of Digital Policy
• /
• v.1 no.1
• /
• pp.15-20
• /
• 2022

Recently, the healthcare field is trying to develop a model that can improve service quality by reflecting the requirements of various industrial fields. In this paper, we propose an Internet of Behavior (IoB) environment model that can process users' healthcare information in real time in a 5G environment to improve healthcare services. The purpose of the proposed model is to analyze the user's healthcare information through deep learning and then check the health status in real time. In this case, the biometric information of the user is transmitted through communication equipment attached to the portable medical equipment, and user authentication is performed through information previously input to the attached IoB device. The difference from the existing IoT healthcare service is that it analyzes the user's habits and behavior patterns and converts them into digital data, and it can induce user-specific behaviors to improve the user's healthcare service based on the collected data.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.4
• /
• pp.91-99
• /
• 2022

By applying METHOD 514.8 of the US military standard MIL-STD-810H, vibration analysis of the winding core automatic feeding device was performed during vehicle transportation. The contact point between the LM guide and main support frame was weak in the vertical axis, transverse axis, and longitudinal axis during the transportation of the automatic winding core feeder vehicle, and the maximum equivalent stress was 236.31 MPa in the longitudinal axis. When random vibration was applied, the safety margin in the longitudinal direction was 0.26, indicating low safety. The safety margin was changed by increasing the damage factor to 0.1. Finally, the safety margin was improved to 3.48 to secure safety. Resonance occurred with a Q factor of 9.34 in the harmonic response to which the RMS value of the ASD data was input, and the vertical axis safety margin was derived as 0.16. When the damping factor was 0.15, the Q factor was 3.37, and resonance was avoided with a safety margin of 6.62.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.3
• /
• pp.9-14
• /
• 2022

In the IoT(internet of things) where various devices can be connected, failure of essential devices may lead to a lot of economic and life losses. For reducing the losses, fault diagnosis techniques have been considered an essential part of IoT. In this paper, the method based on a graph neural network is proposed for determining fault and classifying types by extracting features from vibration data of systems. For training of the deep learning model, fault dataset are used as input data obtained from the CWRU(case western reserve university). To validate the classification performance of the proposed model, a conventional CNN(convolutional neural networks)-based fault classification model is compared with the proposed model. From the simulation results, it was confirmed that the classification performance of the proposed model outweighed the conventional model by up to 5% in the unevenly distributed data. The classification runtime can be improved by lightweight the proposed model in future works.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.3
• /
• pp.292-297
• /
• 2023

Triboelectric devices are attracting attention from researchers as self-powered electronic systems that can instantly convert mechanical input into electrical energy output. To improve triboelectric energy harvesting performance, increasing the number of contacts as well as the contact area has been carried out by numerous researchers. In this study, we design a shaker-type energy harvester which is called as maracas triboelectric generator (M-TEG), inspired by the structure of maracas, one of the musical percussion instruments. A tripod frame is inserted to the inside of a cylindrical case, which is a device with the electrodes of aluminum and copper. Then, the triboelectric energy harvesting characteristics between polypropylene (PP) balls and the electrodes are measured. The M-TEG with the frame generates the energy harvesting signals up to ~100 V and ~2.5 ㎂ due to larger contact area and numbers, which enhances the voltage and current output by 250% and 610% compared to that without the frame, respectively. This study presents the feasibility of self-powered sensors and toys using improved triboelectric energy performance with a low-cost and simple manufacturing process in the interesting structure.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.1
• /
• pp.183-190
• /
• 2009

The core technique of ubiquitous computing is the context aware computing and the context aware technique is more like software so the important research work is to develop the core engines first and the adapted device for the engines. When ubiquitous computing era comes, the current existing internet shopping mall, the form of searching the direct goods and ordering the goods by the customers evolves and develops the form of system that recommends the goods by the search engine which combined with the input data and technique of case based reasoning and intelligent agent that is based on the context aware technique. In this paper, search engine which is based on the case based reasoning and intelligent agent is designed and the prototype is implemented to be adapted to the internet fashion expert shopping mall.

• Convergence Security Journal
• /
• v.22 no.1
• /
• pp.81-92
• /
• 2022

The rapidly growing IoT market is expanding not only in general households but also in smart homes and smart cities. Among the major protocols used in IoT, ZigBee accounts for more than 90% of the smart home's door lock market and is mainly used in miniaturized sensor devices, so the safety of the protocol is very important. However, the device using Zig Bee is not satisfied with the omnidirectional safety because it uses a fixed key during the authentication process that connects to the network, and it has not been resolved in the recently developed ZigBee 3.0. This paper proposes a design method that provides omnidirectional safety to the ZigBee authentication protocol and can be quickly applied to existing protocols. The proposed improved ZigBee authentication protocol analyzed and applied the recently developed OWE protocol to apply ECDH, which has low computational volume and provides omnidirectional safety in IoT. Based on this, it provides the safety of the ZigBee authentication protocol, and it is expected that it will be able to provide user convenience as it does not require a separate certificate or password input.