• Progress in Superconductivity and Cryogenics
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• v.23 no.4
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• pp.19-24
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• 2021

The low normal zone propagation velocity (NZPV) of high-temperature superconducting (HTS) tape leads to a quench protection problem in HTS magnet applications. To overcome this limitation, various studies were conducted on HTS coils without turn-to-turn insulation (NI coils) that can achieve self-protection. On the other hand, NI coils have some disadvantages such as slow charging and discharging time. Previously, the HTS coils with turn-to-turn insulation (INS coils) were operated in power supply (PS) driven mode, which requires physical contact with the external PS at room-temperature, not in persistent current mode. When a quench occurs in INS coils, the low NZPV delays quench detection and protection, thereby damaging the coils. However, the rotary HTS flux pump supplies the DC voltage to the superconducting circuit with INS coils in a non-contact manner, which causes the INS coils to operate in a persistent current mode, while enabling quench protection. In this paper, a new protection characteristic of HTS coils is investigated with INS coils charging through the rotary HTS flux pump. To experimentally verify the quench protection characteristic of the INS coil, we investigated the current magnitude of the superconducting circuit through a quench, which was intentionally generated by thermal disturbances in the INS coil under charging or steady state. Our results confirmed the protection characteristic of INS coils using a rotary HTS flux pump.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.36-48
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• 2019

The purpose of this study is to investigate case studies and industry needs for convergence education in the fields of electronics, software, and automobiles, which are the technical foundations of the Fourth Industrial Revolution. Through the literature review, the convergence education programs focusing on electronics, software, and automobile were derived. The areas were validated by the experts review who consisted of three industry experts and professors in the relevant fields. Domestic and foreign curriculum were investigated to understand the current state of technical convergence education in each field. Industry needs survey for technical convergence education was conducted in cooperation with the Sector Council of Industrial Resources. Research instruments consisted of three parts: needs for technical convergence education, needs for the specific convergence education in the field of electronics, software, and automobile, and opinions on convergence education. A total of 341 participants responded to the questionnaires: 132 in the electronic field, 100 in the software field, and 109 in the automobile field. The industry needs for convergence education were analyzed and implications were suggested. The results of this study are expected to provide a guideline for developing convergence education programs in higher education.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.784-792
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• 2018

In this study, we designed the area except the development market and the traditional market, where large scale shops were concentrated by realizing the real estate center of the alley commercial area. In addition, we have developed an area setting method for the alley area where reliability and rationality can be ensured by utilizing the actual data such as the business statistics, the survey data of the business, and the store business DB, which are managed by the local government or the state. The alley commercial areas were classified into five groups according to density. It is thought that users can distinguish the commercial areas from dense commercial areas to the commercial areas in order to utilize various commercial areas.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.630-635
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• 2018

In this paper, we consider the stability condition for the linear discrete systems with time-varying delay and unstructured uncertainty. The considered system has time invariant system matrices for non-delayed and delayed state variables, but its delay time is time-varying within certain interval and it is subjected to nonlinear unstructured uncertainty which only gives information on uncertainty magnitude. In the many previous literatures, the time-varying delay and unstructured uncertainty can not be dealt in simultaneously but separately. In the paper, new stability conditions are derived for the case to which two factors are subjected together and compared with the existing results considering only one factor. The new stability conditions improving many previous results are proposed as very effective inequality equations without complex numerical algorithms such as LMI(Linear Matrix Inequality) or Lyapunov equation. By numerical examples, it is shown that the proposed conditions are able to include the many existing results and have better performances in the aspects of expandability and effectiveness.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.387-394
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• 2019

The purpose of this study is to analyze and identify the strengths of companies selected in each field based on data released by the IOTONE to see if the most influential companies in the industrial Internet of Things are gaining high competitiveness by exercising their capabilities in each field. The industrial Internet of Things is emerging as an essential element in the overall realm of business activity, as well as to make manufacturing factories competitive smart factories. Appropriate platforms should be applied to apply the industrial Internet of Things throughout the enterprise. Globally, many companies are proposing a platform for the industrial Internet of Things. We analyzed the strengths of the most influential companies in each field of connected machines, cybersecurity, analysis platforms, embedded computing, platform connectivity and hardware connectivity in the industrial Internet of Things, and looked at trends such as the current state of operations and the characteristics of the platform.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.263-269
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• 2019

In this study, the characteristics and operation of a multi-purpose loader equipped with various sensors such as a sensor capable of measuring the boom length, an angle sensor capable of measuring the tilt of the left and right sides of the boom and the loader, and a load cell capable of measuring the weight during lifting We have implemented a system that displays related data values. The configuration of the system reads the values from the sensors, sends them to the vehicle controller, and transmits the calculated results of the overturn rate and other important information to the display device using the CANOpen protocol. Also, in the calculation of the overturn ratio, the structure of the multi-purpose loader is similar to that of the crane belonging to the heavy equipment, and the crane overturn rate calculation method is used. Through this study, we can observe the condition of the heavy equipment and recognize the emergency situations such as abalone through the display device.

• Fashion & Textile Research Journal
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• v.21 no.5
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• pp.618-626
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• 2019

This study conducted basic studies to develop electromagnetic wave shielding maternity wear. We investigated electromagnetic wave shielding fabrics and products as well as surveyed actual wearing states for pregnant women aged 35 to 44 and women who gave birth within the past one year. Available electromagnetic wave blocking products for pregnant women were blankets, aprons, maternity belts, and underwear. These only cover the abdomen and it was hard to find out electromagnetic waves shielding maternity wear, which can enhance functionality and complement the body shapes of pregnant women. The aged mother responded pregnancy delay was mostly attributable to late marriage, career, financial difficulty and health problems. Major health threats to babies were high stress levels during pregnancy, followed by electromagnetic waves from electronic devices. They prioritized physical activity, design, functionality and safety when wearing maternity wear. When purchasing maternity wear, they emphasized design, price, materials and size. The most preferred clothing was one-piece dress; consequently, only 11.1% of them were satisfied with the quality of maternity wear with complaints mostly about design and price. A total of 63% of respondents tried to protect themselves from electromagnetic waves. Most aged mothers showed a positive intention on purchasing electromagnetic waves blocking maternity wear for babies with concerns dealing with safety of materials, prices, ease of laundry, and body complementing design.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.7-12
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• 2019

Ambient backscatter communication is limited to channel estimation technique through a pilot signal, which is a channel estimation method in current RF communication, due to transmission power efficiency. In a limited transmission power environment, the research of traditional ambient backscatter communication has been studied assuming that it is an ideal channel without signal distortions due to channel conditions. In this paper, we propose an expectation-maximization(EM) algorithm, one of the blind channel estimation techniques, as a channel estimation method in ambient backscatter communication system which is the state of channel following normal distribution. In the proposed system model, the simulations confirm that channel estimate through EM algorithm is approaching the lower bound of the mean square error compared with the Bayesian Cramer-Rao Boundary(BCRB) to check performance. It shows that the channel parameter can be estimated in the ambient backscatter communication system.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.469-476
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• 2019

A lead-free bulk ceramic having a chemical formula $Ba_{0.8}Ca_{0.2}(Ti_{0.8}Zr_{0.1}Ce_{0.1})O_3$ (further termed as BCTZCO) is synthesized using mixed oxide route. The structural, dielectric, impedance, and conductivity properties, as well as the modulus of the synthesized sample are discussed in the present work. Analysis of X-ray diffraction data obtained at room temperature reveals the existence of some impurity phases. The natural surface morphology shows close packing of grains with few voids. Attempts have been made to study the (a) effect of microstructures containing grains, grain boundaries, and electrodes on impedance and capacitive characteristics, (b) relationship between properties and crystal structure, and (c) nature of the relaxation mechanism of the prepared samples. The relationship between the structure and physical properties is established. The frequency and temperature dependence of the dielectric properties reveal that this complex system has a high dielectric constant and low tangent loss. An analysis of impedance and related parameters illuminates the contributions of grains. The activation energy is determined for only the high temperature region in the temperature dependent AC conductivity graph. Deviation from the Debye behavior is seen in the Nyquist plot at different temperatures. The relaxation mechanism and the electrical transport properties in the sample are investigated with the help of various spectroscopic (i.e., dielectric, modulus, and impedance) techniques. This lead free sample will serve as a base for device engineering.

• The Korean Journal of Archival Studies
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• no.54
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• pp.45-79
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• 2017

This paper examines the significance of records as knowledge information resources that are illuminated by the electronic record environment nowadays based on existing research results and examples. As the production mode of records changes, it is possible to avoid the tendency to prioritize historical and cultural values when keeping records. In addition, according to the change of the operating mode and the work pattern of an organization, the value of knowledge information resource is also important. For this purpose, this paper reviews the recent changes in the work environment in Chapter 2 and then examines attributes not only as evidence but also as information. Based on these discussions, the paper explores the relationship between the records and the information that has been discussed in western academic circles since the 1980s in Chapter 3. With this, it also analyzes the correlation between record management and knowledge management. In Chapter 4, it reviews recent trends to link records management and knowledge management in Australia, the United Kingdom, and the United States. In addition to the current state of public records management in Korea, this paper presents the direction of institutional improvement in three aspects.