• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.45-56
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• 2023

In this study, the application of ANC (Active Noise Control) technology to address inter-floor noise was explored. To achieve this, an ANC system was developed to manage the heavy impact sound within the frequency range of 40 to 500 Hz. The ANC system utilized an adaptive filter employing a feedforward approach based on the Fx-LMS algorithm. To set up the ANC system, a comprehensive analysis of various variables within the system was performed using computational simulations. This process enabled the identification of optimal filter settings and system configuration arrangements. In addition, the ANC system was implemented in the inter-floor noise test room at the Korea Conformity Laboratories (KCL). Through a certified standard testing procedure, it was confirmed that the ANC system led to a 4 dB reduction in inter-floor noise when the system was activated compared to when it was turned off. The results of this study indicate that the developed ANC system has an effect significant enough to elevate the rating criteria by one level for heavy impact sound.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.552-558
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• 2023

The characteristics of the vibrato of danso, one of the wind instruments in Korean traditional music, have not been studied much. In this study, the characteristics of the vibrato of danso were analyzed using monotones and musical performances. In particular, intonation, vibrato rate, and vibrato extent were measured as a function of time, and their average values for each vibrato tone were also calculated. The results for vibrato rate showed that the vibrato tended to start slowly and then increase very quickly and significantly and the average values for each tone were observed to have a very wide range, which shows that the characteristics of the vibrato of danso are different from those in Western music. In addition, monotones and musical performances showed some different results in vibrato rate and vibrato extent. There have not been many studies that have quantified the intonation, vibrato rate, and vibrato extent in Korean traditional musical instruments, and this is especially true in the case of danso. The results in this study can be used as basic data on danso vibrato. For example, they can be used as reference materials in education, danso virtual instruments, and danso applications.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.211-219
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• 2023

In this study, the importance of each design element was analyzed by surveying experts in the development of Agro-Healing Virtual Reality Therapy System. It was found that the results of experts content importance were consistent with the results of consumer preferences in previous studies, such as psychological and emotional stability as the main effect the importance of sight and hearing, a relatively short time of 30 minutes or less, a low price of 5,000 won or less, technical factors that can satisfy the five senses, and various contents. When the spatial elements of the Agro-Healing Virtual Reality Therapy System were categorized into three major categories: elements and equipment, lines and paths, and sites and spaces, 'flowers', 'playgrounds', 'paths', 'sidewalks', 'rest areas' and 'gardens' were found to be highly important. Among the components of Agro-Healing Virtual Reality Therapy System, the usability was divided into eight major categories, including searchability, attractiveness, cognition, error handling, control, consistency, convenience, and feedback, and the importance was analyzed for each component. The significance of this study is that it suggests the design direction of virtual healing farm systems and provides effective information that can be used in the development of related systems in the future.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.155-162
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• 2023

PURPOSE: The primary objective of this study was to develop a virtual reality-based vestibular rehabilitation system to enhance balance perception, target rehabilitation specialists, and evaluate its usability. A key goal was establishing a system refinement strategy based on the collected data. METHODS: We conducted a study involving ten adults aged 10 to 29 in Gwangju Metropolitan City to evaluate the usability of a virtual reality-based vestibular rehabilitation system to enhance balance perception. After introducing the product and explaining its use to the participants, balance assessments and training were conducted using computerized dynamic posturography (CDP) (also called the test of balance [TOB]). Subsequently, participants were given a questionnaire to evaluate subjective stability, operability, and satisfaction. Frequency analysis was utilized to determine the frequency of the variable values of the measurement items in the survey for descriptive statistics. RESULTS: We found that the average usability score was 2.587. When broken down by category, stability received an average rating of 2.725, operability scored an average of 2.783, and satisfaction averaged 2.454. These findings suggest that most participants experienced positive sentiments and considerable satisfaction. CONCLUSION: The study successfully developed a virtual reality-based vestibular rehabilitation system, which was an improvement over the previous model and addressed its shortcomings. The results show that users with vestibular impairments are satisfied and more engaged with this system, indicating that additional studies are warranted.

• Annual Conference of KIPS
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• 2008.11a
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• pp.296-299
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• 2008

최근 데이터 스트림을 관리하기 위해 DSMS(Data Stream Management System)가 계속적으로 연구 되고 있다. 하지만 데이터 스트림은 방대한 양의 데이터를 처리하기 위하여 실시간성을 갖는 빠른 데이터 처리가 요구되며, 이러한 특성 때문에 데이터 처리의 효율성 증대를 위하여 메모리 관리가 중요하다. 기존 메모리 관리에 대한 연구는 쓰레드 스케줄링을 통한 관리 기법이 연구되었다. 하지만 기존의 연산자 쓰레드 스케줄링과 그래프 쓰레드 스케줄링은 쓰레드 관리의 유연성이 떨어지기 때문에 불규칙적인 데이터 스트림 환경에서는 부적합하다. 또한 하이브리드 멀티 쓰레드 스케줄링 기법은 두 가지 기법의 장점을 결합하였으나 가상 연산자의 일회성 사용으로 쓰레드 관리의 어려움 이 있다. 따라서 본 논문은 공유와 재사용이 가능한 링 연산자를 이용한 링 연산자 쓰레드 스케줄 링 기법을 제안한다. 본 기법은 링 연산자를 통해 새로 입력된 질의의 동일한 연산자 구성은 생성 되어 있는 링 연산자를 공유하거나 재사용하여 불필요한 자원 소모와 자원 할당의 과부하를 줄임으로써 기존 기법에 비해 쓰레드 할당의 수를 감소 시켜 대량의 질의 처리 시 속도를 증가 시켰다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.6
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• pp.919-928
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• 2023

Deep learning technology is used in various fields such as self-driving cars, image creation, and virtual voice implementation, and deep learning accelerators have been developed for high-speed operation in hardware devices. However, several side channel attacks that recover secret information inside the accelerator using side-channel information generated when the deep learning accelerator operates have been recently researched. In this paper, we implemented a DNN(Deep Neural Network)-based MNIST digit classifier on a microprocessor and attempted a correlation power analysis attack to confirm that the weights of deep learning accelerator could be sufficiently recovered. In addition, to counter these power analysis attacks, we proposed a Node-CUT shuffling method that applies the principle of misalignment at the time of power measurement. It was confirmed through experiments that the proposed countermeasure can effectively defend against side-channel attacks, and that the additional calculation amount is reduced by more than 1/3 compared to using the Fisher-Yates shuffling method.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.908-915
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• 2023

Purpose: The purpose of this study is to examine the types of fraudulent crimes among various crimes taking place during NFT transactions, and to approach institutional problems caused by crime types analysis and crackdown methods and legal limitations. Method: IIn order to classify the types of fraudulent crimes that appear in NFT transactions, the crime types were analyzed through the results of previous studies and cases of current incidents. Result: Most of the crimes that are taking place through NFTs are various types of fraudulent crimes such as rug pools, thefts, personal information theft fraud, and pig murder. Therefore, these types were classified and various damage cases were also analyzed. It is a matter of copyright. Conclusion: Currently, the financial problems caused by the occurrence of fraudulent crimes in NFTs worldwide are the most worrisome, and the scale will be even greater as the market grows in the future. Therefore, in Korea, various institutional supplements and policies should be prepared through analysis of crime types that can affect crime prevention and investigation and arrest activities.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.1-10
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• 2023

The nuclear power plant(NPP)'s Instrumentation and Control(I&C) system periodically conducts integrity checks for the maintenance of self-diagnostic function during normal operation. Additionally, it performs functionality and performance checks during planned preventive maintenance periods. However, there is a need for technological development to diagnose failures and prevent accidents in advance. In this paper, we studied methods for estimating the reliability function by utilizing environmental data and self-diagnostic data of the I&C equipment. To obtain failure data, we assumed probability distributions for component features of the I&C equipment and generated virtual failure data. Using this failure data, we estimated the reliability function using representative artificial intelligence(AI) models used in survival analysis(DeepSurve, DeepHit). And we also estimated the reliability function through the Cox regression model of the traditional semi-parametric method. We confirmed the feasibility through the residual lifetime calculations based on environmental and diagnostic data.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.112-118
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• 2023

Internet of Things(IoT) technology is developing to a stage where the Internet and objects are connected and objects themselves analyze and judge data to interconnect the real world and the virtual world in real time. This technology consists of sensors, actuators, devices, and networks, and it is being applied in various fields. As the number of IoT devices and applications increases, data traffic also increases. In this paper, a messaging system is designed and implemented in order to analyze the performance between an IoT device and MQTT broker. The experimental was performed to measure MQTT-based round-trip time and message transmission time between the IoT device and the broker. The result shows that there is no packet loss, and propagation delay affects round-trip time.

• Journal of Korean Elementary Science Education
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• v.43 no.1
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• pp.148-157
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• 2024

The purpose of this study was to develop an artificial intelligence-based marine ecological education program to improve the ecological sensitivity of elementary school students. The program was taught 11 times within 4 weeks, and an ecological sensitivity test was conducted before and after the program. The statistical results of the tests showed that the developed program improved the ecological sensitivity of elementary school students. Through in-depth interviews, improvements were found in all the areas, such as empathy for the living things, interest in nature, enjoyment of nature, and wonder about nature. Through the marine ecological classes, which used artificial intelligence and virtual reality, the students were able to get closer to nature, and the student participation activities showed a positive effect on their ecological sensitivity. This indicates that experience-oriented education methods are more effective than simple explanatory classes to improve the students' ecological sensitivity, and artificial intelligence technology proved effective in increasing the students' immersion in the class.