• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.280-289
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• 2022

In this paper, we present a QRS-complex detection algorithm to calculate an accurate heartbeat and clearly recognize irregular rhythm from ECG signals. The conventional Pan-Tompkins algorithm brings false QRS detection in the derivative when QRS and noise signals have similar instant variation. The proposed algorithm uses amplitude differences in 7 adjacent samples to detect QRS-complex which has the highest amplitude variation. The calculated amplitude is cubed to dominate QRS-complex and the moving average method is applied to diminish the noise signal's amplitude. Finally, a decision rule with a threshold value is applied to detect accurate QRS-complex. The calculated signals with Pan-Tompkins and proposed algorithms were compared by signal-to-noise ratio to evaluate the noise reduction degree. QRS-complex detection performance was confirmed by sensitivity and the positive predictive value(PPV). Normal ECG, muscle noise ECG, PVC, and atrial fibrillation signals were achieved which were measured from an ECG simulator. The signal-to-noise ratio difference between Pan-Tompkins and the proposed algorithm were 8.1, 8.5, 9.6, and 4.7, respectively. All ratio of the proposed algorithm is higher than the Pan-Tompkins values. It indicates that the proposed algorithm is more robust to noise than the Pan-Tompkins algorithm. The Pan-Tompkins algorithm and the proposed algorithm showed similar sensitivity and PPV at most waveforms. However, with a noisy atrial fibrillation signal, the PPV for QRS-complex has different values, 42% for the Pan-Tompkins algorithm and 100% for the proposed algorithm. It means that the proposed algorithm has superiority for QRS-complex detection in a noisy environment.

• Journal of Internet of Things and Convergence
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• v.8 no.4
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• pp.9-15
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• 2022

NAND flash memory is used as a medium for various storage devices due to its high data processing speed with low power consumption. However, since the read processing speed of data is about 10 times faster than the write processing speed, various studies are being conducted to improve the speed difference. In particular, flash dedicated buffer management policies have been studied to improve write speed. However, SSD(solid state disks), which has recently been used for various purposes, is more vulnerable to read performance than write performance. In this paper, we find out why read performance is slower than write performance in SSD composed of NAND flash memory and study buffer management policies to improve it. The buffer management policy proposed in this paper proposes a method of improving the speed of a flash-based storage device by analyzing the pattern of read data and applying a policy of pre-reading data to be requested in the future from NAND flash memory. It also proves the effectiveness of the read-ahead policy through simulation.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.583-589
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• 2022

Due to COVID-19, which has thrown the whole world into chaos, it has become an era where many technologies and contents are made non-face-to-face. At the same time, the popularity of the metaverse service is also increasing day by day, and the virtual costume (avatar) industry, one of the sub-industries, is also growing. In this study, we designed and developed a system for creating virtual costumes to be uploaded to ZEPETO, a mobile metaverse service. Unlike the existing service that requires a program that operates in a PC environment, it can be produced only by shooting and simple operation through a mobile device. With the advantage of being able to process all tasks of this system in a mobile environment, small businesses and individual operators who are not familiar with external programs will be able to more easily access the 3D virtual clothing industry.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.213-218
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• 2023

In order to use the VR HMD, operation through separate controllers in both hands is required. Methods for text input in VR include a method of selecting virtual keyboard keys on the screen one by one using a controller, a method of inputting through a keyboard that is a resource of a computer by connecting a computer and VR, or a method of inputting through a keyboard that is a resource of a computer by purchasing a wireless keyboard in VR and wireless keyboard connection method. As such, the text input method in current VR equipment causes inconvenience and additional costs to users. For these reasons, most of the VR-related contents are limited to simple functions such as games or viewers, and there is a risk that VR equipment will be recognized as a simple game machine. Therefore, in this study, a multi-input interface using hand tracking provided by the Oculus Quest2 device is designed and partially implemented. Through this, it is expected that various tasks such as document work and business processing as well as games can be conveniently used using VR equipment.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.699-705
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• 2022

Purpose: Sequence control is widely used by being applied to manufacturing, distribution, construction, and automation in the medical industry. With the development of the fourth industry, artificial intelligence convergence technology in the control field is becoming an important factor in the industry. In particular, it is required to evaluate the safety and innovation of facilities where microprocessors and artificial intelligence are fused to existing systems and develop reliable equipment, so it is intended to develop equipment for educational purposes and drive the development of the field. Method: The self-developed all-in-one artificial intelligence controller module is a device that combines artificial intelligence capabilities with existing sequence and PLC control circuits. As the performance evaluation items of this equipment, the recognition ability of motion, voice, text, color, etc. and the stability and reliability of the circuit were evaluated. Conclusion: After designing the sequence and PLC circuit, the performance evaluation items of the integrated integrated artificial intelligence controller module were all satisfied, and there was no problem in the safety and reliability of the circuit.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.111-116
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• 2023

Recently, viral infectious diseases and new diseases are not limited to one region, but are spreading worldwide, causing serious economic and social damage. In addition, the development cycle of new diseases is shortening, and the rate of spread is accelerating. In order to prevent the spread of disease, passive forms of response after a disease outbreak, such as personal and regional quarantine and border closure, are prioritized. This type of response has many shortcomings as a fundamental response to preventing the spread of disease. Therefore, this study proposes a disease prevention monitoring system including new disease occurrence information. In this study, disease information and user information are collected through the establishment of the IoMT environment. Information collection using an agent collects and classifies data registered in the disease information server. In the IoMT environment, user data is collected, and whether the user is infected with a disease is evaluated and provided to the user. Through this study, individual disease symptom information can be provided and active countermeasures against the spread of disease can be provided.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.545-550
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• 2023

A pretensioner is a safety device that protects occupants by pulling the seat belt in the event of a vehicle collision. However, since the pretensioner is driven by a explosive method, it is necessary to replace not only the gas generator but also all connecting parts including the manifold after an accident. Therefore, in this paper, we propose an elastic force-based pretensioner that can be used safely and semi-permanently. After analyzing the operating mechanism of the existing pretensioner from a thermodynamic/dynamic point of view, the spring stiffness that can be deployed within an appropriate operating time was determined by converting the gas explosion energy into elastic energy. In addition, the coil spring shape that satisfies the elastic stiffness was designed in consideration of the vehicle interior installation standard. Finally, the operating performance of the pretensioner driven by elastic force was verified through fabrication.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.507-516
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• 2022

The purpose of this study was to examine the factors influencing on the smartphone usage time according to the happiness perceived by adolescents. This study underwent the approval procedure for using the raw data of the 13th (2017) Adolescents' Health Behavior Online Survey through the homepage of Korea Centers for Disease Control and Prevention and selected 54,603 persons of 12-18 age groups as subjects of the study. The analysis was performed after generating a complex sample plan file by assigning weights using the IBM SPSS 23.0 program. There were significant differences in general characteristics and physical & psychological characteristics according to the use of the smartphone in the happy group and the unhappy group (p<.05). And there was a statistically significant difference in factors affecting smartphone usage time between the group of adolescents who perceived as happy and the group who perceived themselves as unhappy. It is necessary to improve the quality of life by increasing the level of happiness through the correct use of smartphones among adolescents.

• Journal of IKEEE
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• v.26 no.1
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• pp.27-35
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• 2022

This paper proposes an ultrasound vessel-pattern imaging algorithm with low computational complexity. The proposed imaging algorithm reconstructs blood-vessel patterns by only detecting blood flow, and can be applied to a real-time signal processing hardware that extracts an ultrasonic finger-vessel pattern. Unlike a blood-flow imaging mode of typical ultrasound medical imaging device, the proposed imaging algorithm only reconstructs a presence of blood flow as an image. That is, since the proposed algorithm does not use an I/Q demodulation and detects a presence of blood flow by accumulating an absolute value of the clutter-filter output, a structure of the algorithm is relatively simple. To verify a complexity of the proposed algorithm, a simulation model for finger vessel was implemented using Field-II program. Through the behavioral simulation, it was confirmed that the processing time of the proposed algorithm is around 54 times less than that of the typical color-flow mode. Considering the required main building blocks and the amount of computation, the proposed algorithm is simple to implement in hardware such as an FPGA and an ASIC.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.577-585
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• 2023

This study applied ALOHA Program to predict the damage caused by fire and explosion predicted to occur from gas leakage at LPG stations and presented plans to prevent damages by diagramming the impact range and distance. The propane gas leakage from LPG stations causes human damage like breathing issues and property damage, including building destruction to residents in the surrounding areas. As a way to reduce this, first, the hazardous substance safety manager of the LPG station needs to check frequently whether the meters and safety valves are working properly to prevent leakage in advance. Second, the LPG stations' storage tanks should be worked by the person who received "hazardous substance safety manager training" under the provisions of the Act on the Safety Control of Hazardous Substances and has been appointed as a "hazardous substance safety manager" by the fire department. Third, LPG station's various safety device functions, such as overfill prevention devices, must be checked on a regular basis. Finally, wearing work clothes and shoes that prevent static electricity at LPG stations is highly recommended, as static can cause a fire when gas leaks.