• Clean Technology
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• v.30 no.3
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• pp.159-174
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• 2024

The rapid increase in energy consumption based on fossil fuels is accelerating global warming. In particular, the road transportation sector has high carbon dioxide emissions, so transitioning towards electric vehicles is recommended. Thus, the importance of secondary batteries is increasing. Secondary batteries are reversible batteries that use energy and can be reused through a charging and discharging process. Currently, lithium-ion batteries are widely used. Secondary batteries place importance on six major factors: energy, output, lifespan, environmental friendliness, cost, and stability. Research is actively being conducted to satisfy all six factors by understanding the material characteristics of each component of the battery. As it is difficult to move away from lithium as a cathode material, researchers are investigating higher performance materials that mix materials such as cobalt, nickel, manganese, and aluminum with lithium and use graphite, silicon, and lithium metal to increase capacity. In the case of electrolytes, liquid electrolytes are still mainly used. However, solid electrolytes are being studied due to their stability, but additional research must be conducted to satisfy the energy and output factors. This review paper aims to provide an understanding of secondary batteries through an overview of secondary batteries, the materials and characteristics of their components, their technological trends, and their associated companies.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.245-251
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• 2015

If a digital signage system is operated in PC mounted in the Window OS then the implementing price is very high. For resolving this problem, we used the Smartphone mounted in ARM Cortex family of multi-core processor-based mobile platform. We developed a low-power low-cost digital signage system and a remote convergence content management program based on web server. This convergence system manages advertising content to a remote control device anywhere using remote control technology. This system is one integrated system with display and is a low-power consumed and is developed in very efficient hardware interface. And condition sensors(intensity of illumination, temperature, weather, GPS etc) is equipped in the developed system. Automatic contents builder and Context-aware SMIL module is also implemented in the convergence system. We achieved over 50% power savings comparing with conventional Window OS system and 16 points multi-touch in our system.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.421-426
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• 2018

This study is meant to derive what is needed to enhance the convenience and satisfaction of users of mobile credit card applications. For the first step, the current status of simple payment service using application has been identified and in-depth interview by reorganizing Peter Morvile's Honeycomb model into the five usage principle based on the main function of the application card. As a result, it was found that users prefer personalized services that fulfill the purpose and key functions of the app card and take into account their consumption patterns rather than too many additional functions. Based on this study, it is expected that it would help card companies increase their experience with app card users and strengthen their platforms.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.77-85
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• 2009

Execution times of tasks can be variable depend on input data. If we choose a high performance processor to satisfy the worst case execution times, the hard cost becomes high and the energy consumption also becomes large. To apply a lower performance processor, we have to utilize processor capacity maximally while overrunning tasks can not affect deadlines of other tasks. To be used for such systems, this paper presents SBP (Shared Bandwidth Partitioning) that a processor bandwidth is reserved and shared among all tasks. If a task needs more processor capacity, it can use a portion of the shared bandwidth. A simulation result shows that SBP provides better performance than previous algorithms. SBP reduces deadline miss ratio which is related to scheduling quality. And the number of context switches, which is related to system overhead, is also reduced.

• The Journal of the Convergence on Culture Technology
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• v.1 no.3
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• pp.23-30
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• 2015

Aroma therapy was used for religious or healing purpose in the world throughout the history. In these days, numbers of people use aroma therapy for various reasons such as mental health issue. Aroma diffusers are made with various subjects, but most are made with volatilization and candle by using fumigation method. Korea's a grayish-blue-powdered celadon has insignificant position in both traditional and cultural value. Grayish-blue-powdered celadon must constantly develop its style and design and collaborate with modern product to meet the demand of the today's market. In this research, it will find the method to develop an aroma diffuser by using a grayish-blue-powdered celadon to meet consumer's demand. And ultimately, this research will construct a cultural infrastructure based on traditional image and by adding more value on the traditional ceramics market.

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.238-244
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• 2020

The development and distribution rate of smartphones have progressed so rapidly that it is safe for the entire nation to use them in the smart age, and the use of smartphones has become an essential medium for the use of domestic media content, and many people are using various contents regardless of gender, age, or region. Recently, various media outlets have been consuming video content for online learning, indicating that learners utilize video content online for learning. In the previous research, satisfaction studies were conducted according to the type of content, and the improvement plan was necessary because no research was conducted on how to evaluate the learning content itself and provide it to learners. In this paper, we would like to propose a system through evaluation and review of learning content itself as a way to improve the way of providing video content for learning and quality learning content.

• Culinary science and hospitality research
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• v.24 no.3
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• pp.71-82
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• 2018

The purpose of this study was to investigate relationship between eating out consumption propensity, dessert $caf{\acute{e}}$ satisfaction, psychological well-being, and quality of life. The objective of this study was reached by verifying a hypothesis through empirical analysis. Data collection was conducted from November 10, 2017 to December 10, 2015, and 250 copies of the questionnaires were distributed. Of these, 243 valid copies of the data were used for the analysis except for the questionnaires that did not meet the research purpose. The results of the analysis were as follows. First, only health pursuit type and quick & convenience pursuit type had a significant influence on satisfaction of dessert cafe. On the other hand, economic value pursuit type, eating out enjoyment pursuit type, and atmosphere pursuit type did not significantly affect dessert cafe satisfaction. Second, among the eating out consumption propensity, there were significant influences on psychological well-being in order of atmosphere pursuit type, eating out enjoyment pursuit type, economic value pursuit type. On the other hand, the health pursuit type and the quick & convenience pursuit type did not significantly affect psychological well-being. Third, satisfaction of dessert cafe had a significant effect on psychological well-being. Fourth, psychological well-being has a significant effect on the quality of life compared to dessert cafe satisfaction. The result of this study is supposed to be utilized as an instrumental data for establishing a strategy for differentiating dessert cafe to improve the quality of life through grasping the eating out consumption propensity to increase satisfaction and psychological well-being in dessert cafe.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1574-1579
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• 2016

This paper presents a self-powered sensor-node scheme using a RF wireless power harvesting techniques for improve drone time of flight. Sensor-node that is proposed is turned when two conditions satisfy: The one is input RF ID data from master-node should be same with sensor-node's ID, and the other one is RF wireless power harvesting system is turned on by hysteresis switch. In this paper, master-node's output is 26 dBm at 263 MHz. Maximum RF to DC power conversion efficiency is about 55% at 4-6 dBm input power condition (2 meter from master-node). The maximum RF wireless power harvesting range is about 13 meter form master-node. And power consumption of the sensor-node's load elements such as transmitter, MCU and temperature sensors is approximately average 15 mA at 5.0 V for 10 msec.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.629-634
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• 2010

Natural gas is a promising alternative fuel that can be used to satisfy the strict engine emission regulations in many countries. To develop natural-gas engines, low emission, efficient fuel consumption, and increased power ratings have to be realized. In this study, a cylindrical constant-volume combustion chamber (CVCC) was used to investigate natural-gas combustion characteristics for different prechamber design parameters and equivalence ratios. In particular, the maximum combustion pressure and mass fraction of the burned gas were evaluated by considering orifice diameter, volume ratio of prechamber and equivalence ratio. Using this result and by analyzing the changes in combustion characteristics with variations in design parameters, the optimum prechamber parameters were determined.

• Archives of design research
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• v.16 no.3
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• pp.299-308
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• 2003

The existing market patterns and social structures have been changed according to the trends of digital and informational society of the 21st century. The characteristics of the consumption market is that the balance of power moves from enterprises to consumers. As consumers’ demands are diversified according to life quality enhancement, many products are based on main aspects of human experiences, emotions and values. Standardized functions and services of products cannot capture consumers to a great extent any more. A notable aspect is that consumers want products or services that can oner movable experiences. Future products must appeal to emotion, not to reason of consumers. Now consumers purchase styles, experiences and stories contained in products, not products themselves. That is, the key to decision to purchase products is the satisfaction of emotional values. Users'emotions diversified due to the development of industrial designs demand the development of new designs that can represent new trends of users. User-centered values imply the change of people's purchasing trends. This indicates that there is a need to change physical aspects such as price or functions into individual emotions and characters. In addition, studies are required on design concepts to pursue new emotional values, apart from functional type designs. It is time for designers to suggest initiative and rational directions for this changing era.