• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.855-863
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• 2017

Because Li-ion battery and Li-Polymer battery have high-energy storage density, they are used for various electronic devices such as electronic cigarette, electronic bicycle, drone, second battery, even golf cart and electronic car. Recently, however, battery explosion is sometimes occurring on electronic devices using Li-ion battery and is becoming serious as bodily harm is breaking out due to explosion. For this, this paper described the Li-ion Battery's operating principles and verified the cause of explosion by overload tests caused by the high-energy storage density. According to the these experiments, we conducted a study to develope scanning techniques of fire and safety measures.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.103-112
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• 2018

In this paper, we propose a method of recognizing emotions using PPG sensor which measures blood flow according to emotion. From the existing PPG signal, we use a method of determining positive emotions and negative emotions in the frequency domain through PSD (Power Spectrum Density). Based on James R. Russell's two-dimensional prototype model, we classify emotions as joy, sadness, irritability, and calmness and examine their association with the magnitude of energy in the frequency domain. It is significant that this study used the same PPG sensor used in wearable devices to measure the top four kinds of emotions in the frequency domain through image experiments. Through the questionnaire, the accuracy, the immersion level according to the individual, the emotional change, and the biofeedback for the image were collected. The proposed method is expected to be various development such as commercial application service using PPG and mobile application prediction service by merging with context information of existing smart phone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5C
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• pp.420-428
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• 2012

One of the most important means in modern NQ emphasized smart society is the communication skill. Especially, effects on improving pronunciation accuracy, it is mostly necessary to accurately express his or her own idea due to the personal relation influence 38% of voice. For this, this paper proposed the voice influence analysis of carbonate drink and eucalyptus fragrance. In particular, in the case of carbonate drink, the amounts of drinking accumulation is verified for analysing the drinking accumulation influence. Also, eucalyptus fragrance is reported for influencing the pronunciation accuracy. For this, jitter, shimmer, pitch and intensity of voice is analyzed. Finally, we accomplish an voice analysis of quantization, objective and visualization for such carbonate drink and eucalyptus fragrance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.347-353
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• 2017

In order to prohibit global warming, various kinds of regulatory policies have been established in the whole world. One example is the establishment of the Renewable Portfolio Standard. It requires the increased portion in energy production from renewable energy sources. The Republic of Korea adopted the act on the promotion of the development, use, and diffusion of new and renewable energy since 2012. However, in spite of the effort on the consideration of the renewable energy sources, it was reported the carbon intensity of electricity in Korea was not that low in 2015. Thus, it is required to examine the recent state of the utilization degree of the renewable energy sources in Korea. This paper analyzed the statistical data provided by Korea Power Exchange (KPX) to examine any problems and solutions for generating electricity from the renewable energy sources. We focused on the generation capacity provided by the power plants participated in the market, the electric power trading amount, and the utilization coefficient for 10 years. By analyzing the data, we provide an alternative to solve some imbalance among the factors contributing to renewable energy use.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.2
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• pp.81-86
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• 2014

In this paper, we present an effective sound classification system for recognizing the real-time context of a smartphone user. Our system avoids unnecessary consumption of limited computational resource by filtering both silence and white noise out of input sound data in the pre-processing step. It also improves the classification performance on low energy-level sounds by amplifying them as pre-processing. Moreover, for efficient learning and application of HMM classification models, our system executes the dimension reduction and discretization on the feature vectors through k-means clustering. We collected a large amount of 8 different type sound data from daily life in a university research building and then conducted experiments using them. Through these experiments, our system showed high classification performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.6
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• pp.449-453
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• 2021

Interest and investment in renewable energy have increased worldwide, highlighting the need for renewable energy. Solar energy was the most promising energy of all renewable energy sources, and it has the highest investment value. Because photovoltaics require a certain amount of area for installation, high density and high output performance are required. Shingled module is a promising technology in that they are featured by higher density and higher output compared to the conventional modules. Shingled technology uses a laser scribing to divide solar cells that are to be bonded with electrically conductive adhesive (ECA) to produce and connect strings, which has a higher output in the same area than the conventional modules. In the process of producing solar modules, metal ribbons are used to interconnect cells, but they are also needed for string connections in shingled solar cells. Accordingly, in this study, we researched the interconnection that best suits the connector that joins the string to the string. The module outputs produced under the conditions of the string interconnection were compared and analyzed.

• Journal of Korea Foundry Society
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• v.41 no.5
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• pp.445-453
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• 2021

Computational thermodynamics for various alloy systems is well known as the CALPHAD technique. Gibbs energy model parameters for each phase are obtained from experimentally measured thermodynamic properties and are mainly used to predict areas not experimentally measured and to analyze experimental results thermodynamically. In this study, the thermodynamic modeling of the Ni-Cr-Nb-C quaternary system is conducted for a thermodynamic analysis of the phenomena by which heat-resistant cast alloys (IN-657) are destroyed in certain areas after long-term use. The stable phases in the system according to the Cr content, phase fraction depending on the temperature, and long-range ordering parameters for the Ni₂Cr phase are calculated and compared to results obtained experimentally. The calculated thermodynamic properties suitably explain the experimentally reported fracture temperature range and the results of stable phases formed in the fractured areas. Thermodynamic modeling through the CALPHD method is expected to be useful for analyzing and predicting the thermodynamic behaviors of various cast alloys.

• Journal of Broadcast Engineering
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• v.26 no.5
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• pp.643-651
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• 2021

Most people acquire information visually. Screens of computers, smart phones, etc. constantly stimulate people's eyes, increasing fatigue. In this social phenomenon, the realistic and rich sound of the 21st century's state-of-art sound system can affect people's bodies and minds in various ways. Through sound, human beings are given space to calm and observe themselves. The purpose of this paper is to introduce immersive yoga training based on 3D sound conducted together by ALgruppe & Rory's PranaLab and to promote the understanding of immersive audio system. As a result, people, experienced immersive yoga, not only enjoy the effect of sound, but also receive a powerful energy that gives them a sense of inner self-awareness. This is a response to multidisciplinary exchange required by the knowledge of modern society, and at the same time, informs the possibility of new cultural contents.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.123-128
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• 2021

As the spread of DC power distribution systems increases, the occurrence of failures and fire accidents are also increasing. In particular, the ESS fire accident, which is a component of the smart grid, and the fire accident of the solar power system, which is a direct current system, are caused by problems in the electrical connection between system components as the supply of new and renewable energy rapidly increases and old facilities increase. An arc that can cause a direct fire by releasing the induced light and heat has been pointed out as one of the causes of fire. Therefore, the problem of such an arc defect is that it is impossible to block an arc accident in advance with the existing overcurrent circuit breaker and earth leakage circuit breaker. In this paper, we intend to develop a test equipment that satisfies international standardization and to develop a DC arc generator to protect against failure and fire caused by arcing.

• Journal of Convergence for Information Technology
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• v.9 no.1
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• pp.116-122
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• 2019

In recent years, small and medium-sized businesses are rapidly changing to an industrial structure where process/quality/energy data aggregates can be automatically or real-time to achieve global competitiveness. In particular, real-time information analysis produced in the production process of small businesses is evolving into a new process process that analyzes, predicts, prescribes and implements significant performance of small businesses. In this paper, we propose a platform-building model that can transform the automated production information system of small businesses into big data so that they can upgrade data that is generated by small businesses. The proposed model has the capability to support operational efficiency (consulting and training) and strategic decision making of small businesses by utilizing a variety of data on the basic information of products produced by small businesses for data collection by smart SMEs. In addition, the proposed model is characterized by close cooperation between small and medium-sized businesses with different regional characteristics and areas of information sharing and system linkage.