• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.315-324
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• 2018

Purpose: This paper propose a temporary indoor positioning scheme with devices of internet of things (IoT) for disastrous situations in places without the infrastructure of networks. Method: The proposed scheme is based on the weighted centroid localization scheme that can estimate the position of a target with simple computation. Results: It also is implemented with the IoT devices at the underground parking lot, where the network is not installed, of general office building. According to the experiment results, the positioning error was around 10m without a priori calibration process at $82.5m{\times}56.4m$ underground space. Conclusion: The proposed scheme can be deployed many places without the infrastructure of networks, such as parking lots, warehouses, factory, etc.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.207-214
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• 2021

Humans are environmentally exposed to various electromagnetic fields, but the evaluation of the harmfulness of electromagnetic field and the development of a system therefor are still incomplete. We aimed to develop a system for evaluating biohazard against electromagnetic fields, and to determine biohazard through the system. An extremely-low frequency magnetic field generator was designed and manufactured, and the output reliability of the device was verified. Using this device, the effect on the formation of cellular stress-granules and the cell cycle progression of cells exposed to high magnetic fields of 6 mT and 60 Hz was confirmed. As a result, exposure to high magnetic fields of 6 hr, 12 hr and 36 hr did not affect the formation of cell stress-induced granules and the cell division cycle. These results are an important basis for the determination of biohazard to the extremely-low frequency high magnetic field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.633-637
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• 2023

Recently, with the development of the smart device market, the integration of high-functional devices has increased the heat density, causing overload of the device, and resulting in various problems such as shortened lifespan, performance degradation, and failure. Therefore, research on heat dissipation materials is being actively conducted to realize next-generation electronic products. The heat dissipation material is characterized in that it is easy to dissipate heat due to its high thermal conductivity and minimizes leakage current flowing through the heat dissipation material due to its low electrical conductivity. In this study, flower-shaped Al₂O₃ and BN composites were engineered with a simple hydrothermal synthesis approach, and their thermal conductivity characteristics were compared and evaluated for each synthesis condition for the application to a heat dissipation material. Spherical BN and flower-shaped Al₂O₃ were easily obtained, and SEM/EDS analyses confirmed the uniform presence of BN between the Al₂O₃, and it can be expected that these shapes can affect the thermal conductivity.

• 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 the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.1
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• pp.17-23
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• 2013

The BESS(Battery Energy Storage System) is an useful device for load leveling, but the high cost, installation space and safety issues are the main barriers for supplying it widely. The important factor in supplying BESS to customers successfully is the payback period. As most of the H/W cost factors are uncontrollable, the optimization of storage volume can be useful factor in improving payback period. In order to obtain optimized BESS volume, the load factor, demand ratio, peak shaving ratio, electric rates and benefits from DR participation of customer should be analyzed. In this paper, we could verify the peak cutting capability and cost effectiveness under the some proposed conditions and changing value of PCS and battery based on the customers data after volume optimization process was applied, and we can identified the saturation point of load factor and shortening of customer's payback period.

• Journal of Information Technology Applications and Management
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• v.20 no.3_spc
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• pp.295-314
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• 2013

These days a great mix of traditional and digital contents such as movie, broadcasting, advertisement, e-books, music, game, animation, cartoon, character, knowledge information, and art performance are widely available. Many more are yet to come, with improved quality and added features. It is expected that all these contents will be evolved into a new breed of convergence content through the process of consolidation, expansion, integration, and recreation. Across the digital ecosystem, a new formula is being added to the industrial structure : 'Information/Content-Platform/Device-Goods/Service.' In the near future, as a result of technological innovation and convergence, the business sector will lose its boundaries as well, as businesses will be forced to look beyond the product itself and focus more on multi-functionality. Especially, in the era of creative economy, more policies need to be crafted in order to procure a new growth engine for the future with the agenda for convergence between humanities and technology. Therefore, the purpose of this paper is to analyze the concept, factors, elements, types, and cases of convergence, which are the essence of content convergence. This analysis, with its focus on the convergence process, will help identify the effects and limits of content convergence as well as the prospects for convergence contents in the smart ecosystem under the creative economic system.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.74-79
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• 2014

Illumination is an effective technique that must be in the mankind today. These lights, there is artificial light that is created by using an artificial light source daylight illumination by sunlight, in this paper, it is created using the electrical energy it is a paper on the study of technology management scheme and efficient control technology of artificial light.

• Smart Structures and Systems
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• v.14 no.6
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• pp.1151-1172
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• 2014

This paper presents a user programmable computational/control platform developed to conduct real-time hybrid simulation (RTHS). The architecture of this platform is based on the integration of a real-time controller and a field programmable gate array (FPGA).This not only enables the user to apply user-defined control laws to control the experimental substructures, but also provides ample computational resources to run the integration algorithm and analytical substructure state determination in real-time. In this platform the need for SCRAMNet as the communication device between real-time and servo-control workstations has been eliminated which was a critical component in several former RTHS platforms. The accuracy of the servo-hydraulic actuator displacement control, where the control tasks get executed on the FPGA was verified using single-degree-of-freedom (SDOF) and 2 degrees-of-freedom (2DOF) experimental substructures. Finally, the functionality of the proposed system as a robust and reliable RTHS platform for performance evaluation of structural systems was validated by conducting real-time hybrid simulation of a three story nonlinear structure with SDOF and 2DOF experimental substructures. Also, tracking indicators were employed to assess the accuracy of the results.

• Journal of the Korea Convergence Society
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• v.6 no.3
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• pp.97-102
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• 2015

It has been changed various patterns related with our consumption because of popularization and progress on mobile device and service. We can buy a necessary products anywhere and at any time during 24 hours. Through the change of patterns in our life, in recent years, Fintech attracts a lot of attention. Fintech is the fusion type of finance and technology. Industry fields related with Fintech are now proceeding well in america, england and china. Therefore, we studied the issues of Fintech, and described the industrial technology trends in this paper.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.21-29
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• 2015

The Internet of Things (IoT) is an Infrastructure which allows to connect with each device in physical world through the Internet. Thus IoT enables to provide meahup services or intelligent services to human user using collected data from those devices. Due to these advantages, IoT is used in divers service domains such as traffic, distribution, healthcare, and smart city. However, current IoT provides restricted services because it only supports monitor and control devices according to collected data from the devices. To resolve this problem, we propose a design and implementation of personalized IoT service base on service orchestration. The proposed service allows to discover specific services and then to combine the services according to a user location. To this end, we develop a service ontology to interpret user information according to meanings and smartphone web app to use the IoT service by human user. We also develop a service platform to work with external IoT platform. Finally, to show feasibility, we evaluate the proposed system via study.