• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.213-218
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• 2021

It is known that total least-squares method shows better estimation performance than least-squares method when noise is present at the input and output at the same time. When total least squares method is applied to data with time series characteristics, Recursive Total Least Squares (RTS) algorithm has been proposed to improve the real-time performance. However, RTLS has numerical instability in calculating the inverse matrix. In this paper, we propose an algorithm for reducing numerical instability as well as having similar convergence to RTLS. For this algorithm, we propose a new RTLS using Iterative Wiener Filter (IWF). Through the simulation, it is shown that the convergence of the proposed algorithm is similar to that of the RTLS, and the numerical robustness is superior to the RTLS.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.5-22
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• 2021

Digital Twin for Land(DTL) is one of the national work projects in the Korean New Deal but there aren't still any standards and technical guides which would need to construct the DTL. This study presents the policies to develop reference model and data model based on geo-spatial information standards to ensure interoperability for the DTL. In this paper, we first extract the implications through reviewing definitions of Digital Twin used in various literatures and international standardization trends on Digital Twin. In addition, this study attempts to conceptualize the DTL through various ways such as defining the DTL and characterizing DTL domains. Finally, we propose three policies on the standardization of the DTS: (1) DTS reference model by using RM-ODP, (2) three-steps hierarchical data models, and (3) model registry to manage the data models efficiently. The proposed policies of the study would contribute to establish a way for DTS's standards development over the coming years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.627-632
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• 2021

ITL (information-theoretic learning) has been applied successfully to adaptive signal processing and machine learning applications, but there are difficulties in deciding the kernel size, which has a great impact on the system performance. The correntropy algorithm, one of the ITL methods, has superior properties of impulsive-noise robustness and channel-distortion compensation. On the other hand, it is also sensitive to the kernel sizes that can lead to system instability. In this paper, considering the sensitivity of the kernel size cubed in the denominator of the cost function slope, a new adaptive kernel estimation method using the rate of change in error power in respect to the kernel size variation is proposed for the correntropy algorithm. In a distortion-compensation experiment for impulsive-noise and multipath-distorted channel, the performance of the proposed kernel-adjusted correntropy algorithm was examined. The proposed method shows a two times faster convergence speed than the conventional algorithm with a fixed kernel size. In addition, the proposed algorithm converged appropriately for kernel sizes ranging from 2.0 to 6.0. Hence, the proposed method has a wide acceptable margin of initial kernel sizes.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.59-64
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• 2020

Recently, many difficulties have been faced in all parts of the world due to the impact of COVID-19. Personally, household income is decreasing sharply as many jobs disappear, and economically, many SMEs are increasingly going bankrupt. It is known that this phenomenon is highly likely to continue for the time being. In such a situation, the smart factory support project provides opportunities for difficult SMEs to improve productivity and change the corporate structure. In this study, the current status of smart factory promotion was examined, and problems occurring in the process of promoting smart factory support projects were identified. The improvement plans were derived so that more efficient projects could be promoted in the future.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.601-606
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• 2020

In this paper, we designed a microstrip patch antenna that can be applied to the Wimax/LTE 5G system among wireless media usable in coastal ships. The substrate of the proposed antenna is FR-4 (er=4.3), the size is 22 mm × 30 mm, and it can be used in the 3.5 GHz and 5.8 GHz bands of Wimax/LTE 5G by constructing a simple structure using a microstrip patch antenna. CST Microwave Studio 2014 was used for simulation, and the gain of the simulation result is 2.41dB at 2.4 GHz and 3.96 dB at 3.5 GHz. S-Parameter also showed a result of less than -10 dB (VSWR 2:1) in the desired frequency band, and designed a small variable and a miniaturized antenna so that the antenna can be used in mobile phones or electronic devices.

• Journal of Internet of Things and Convergence
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• v.7 no.1
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• pp.55-62
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• 2021

The world is changing rapidly as the Internet spreads and various smart devices appear. High-performance PCs and high-speed communication networks are rapidly spreading in every home, and all kinds of the internet sites are emerging. In particular, the high education enthusiasm of Korean parents adds to this, and the ratio of the internet users among teenagers is exploding every day. In the case of adolescents, most of them use the Internet for online games, indicating that online games are the main cause of the internet addiction. This study was conducted using a questionnaire for male and female high school students using the Internet, and demographic and sociological characteristics were used only as basic data. In this study, as much as parents, students and teachers think, the results of the internet addiction type analysis according to academic achievement in humanities high school students are to be investigated to determine whether internet use has an effect on academic achievement.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.84-93
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• 2021

Each equipment has a durable life. The state of the equipment may change or fail until it is introduced, operated and disposed of. It is difficult for each organization to have a significant amount of these equipment and to understand each issue. Therefore, systematic life cycle management of equipment is more necessary than just for inventory purposes. In this paper, we design and implement an integrated management system for information assets. If it is an environment that can use the Internet based on the web, it can easily and easily access computerized information resource data through PCs, tablets, and smartphones. In addition, an integrated management system was established to limit the functions of higher and lower institutions through centralized management and user-level empowerment methods and to understand the overall status of resources.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.13-21
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• 2021

This study aims to analyze tourist inflow trends and consumption patterns using a geographic information system and big data analysis system. Songdo Central Park and Chinatown were selected among the major tourist destinations in Incheon, and floating population analysis and card sales analysis were conducted for one month in June 2017. The number of tourists visiting Songdo Central Park from metropolitan cities across the country was highest in the order of Incheon Metropolitan City, Gyeonggi-do, and Seoul Metropolitan City, and the proportion of foreign tourists was the highest in China. The number of card consumption used by Chinatown tourists was 12.4% higher for men than for women, and the amount of card consumption was also higher for men by 18%. This study has implications for proposing a strategic plan for tourism policy by analyzing the inflow trend and consumption pattern of tourists and deriving major issues in the establishment of tourism policy. Based on this study, it is expected that it can be helpful in improving the construction of tourism infrastructure in the future.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.3
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• pp.1-7
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• 2021

Appropriate containers are deployed to cope with new request arrivals at Fog Computing (FC) hosts. In the case, we can consider two scenarios: (1) the requests may be queued until sufficient resources are prepared for the container deployments; (2) FC hosts may transfer arrived service requests to nearby FC hosts when they cannot accommodate new container deployments due to their limited or insufficient resources. Herein, for more employed neighboring FC hosts, arrived service requests may experience shorter waiting time in container deployment queue of each FC host. In contrast, they may take longer transfer time to pass through increased number of FC hosts. For this reason, there exists a trade-off relationship in the container deployment time depending on the number of employed FC hosts accommodating service request arrivals. Consequently, we numerically analyze the trade-off relationship to employ optimal number of neighboring FC hosts.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.21-27
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• 2021

The paper, in an online learning environment which becomes prolonged for reason of COVID-19, on 80 students belonging to the aviation and aeronautics, proposed more concrete direction for raising effectiveness of online class by analyses of various standpoints regarding the relation between 8 detailed elements of self-initiated learning ability and learning satisfaction. As a result of analyses, first, it turned out that, among detailed elements of self -initiated learning ability, relatively high scores were showed in basic self management ability, grasp of resources for learning, attribution of efforts to results, and selection of learning strategies. Second, in correlation between self-initiated learning ability detailed elements and learning satisfaction and technical statistical analyses, the score of the two elements: learning goal setting and continuance of learning execution is low, so that it is necessary to note the two elements. Third, as to self-initiated learning ability, the average of female students is high and in learning satisfaction, the average of male students was high. Fourth, it was found that the first-class students showed significantly high learning satisfaction compared with the second-class students. Fourth it turned out that, regarding a difference, both of self-initiated learning ability and learning satisfaction were dismissed and thus there is no difference. Fifth, as to the effects of self-initiated learning ability on learning satisfaction, both of a corelation analysis and a regression analysis showed significant results. Accordingly, self-initiated learning ability in online class has a very significant effect on learning satisfaction.