• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.17-22
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• 2015

In recent years, wireless sensor networks have become an important part of data communications. Sensors provide information about the required measurements or control states over wireless networks. The energy efficient routing protocol of wireless sensor networks is the key issue for network lifetimes. The routing protocol must ensure that connectivity in a network is remained for a long period of time and the energy status of the sensor in the entire network must be in the same level in order not to leave the network with a wide difference in the energy consumptions of the sensors. In this paper we propose a new routing protocol based on AODV protocol that considers the energy efficiency when the protocol determines the routing paths, which is called AODV-EE. The proposed method prevents an imbalance of power consumption in sensors of wireless networks. From the simulation results it is shown that the proposed algorithm can be effectively used in collecting and monitoring data without concerning about the disconnection of the networks.

• The Research Journal of the Costume Culture
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• v.15 no.4
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• pp.593-603
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• 2007

The purpose of this study is to study the Central Asian costumes($1{\sim}7C$) and develop new design items and suggest new brand launching. Korean apparel industry has been suffering from imbalance of supply and demand caused by the sagging economy and too many apparel companies. Due to the several years of recession, clothing consumption decreased and foreign brand's market share got bigger. As a result, managing a company became difficult and it is time for Korean apparel industry to enter the global market. We need a brand with new image and design that has big potential of purchasing power not only in Korea but also in China, and furthermore in global market. But even nearby Chinese market already became very competitive. One way of approaching Chinese fashion market is to find something special, for example, their historical background. Central Asian culture and costumes, a part of China, has both Eastern and Western culture. No other apparel industry had interest in the Central Asian costumes yet. Therefore, through their costume, a fresh design idea can be suggested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10A
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• pp.997-1005
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• 2008

In this paper, we propose an efficient space-time block coding (STBC) scheme in a cooperative satellite-terrestrial system. The proposed STBC scheme has code rate 1 for a 3 transmit antenna scheme. Because the channel matrix of the proposed scheme is orthogonal, we can use a simple linear decoding algorithm and also can expect improved performance over the conventional scheme. The simulation results demonstrate that the proposed scheme has improved performance for bit error rates (BER) than several conventional STBC schemes. In addition, we investigate performance simulation results by power imbalance between the terrestrial repeaters and satellite.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.277-279
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• 2005

The imbalance of energy demand and supply caused by rapid industrialization around the world and the associated environmental issues require and alternative energy source with possible renewable fuels. Political instability and depletion of cruel oils are other factors that cause fluctuation of oil price. Securing a new alternative energy source for the next century became an urgent issue that our nation is confronting with. As a matter of fact, the fuel cell technology can be widely used as next generation energy regardless of regions and climate. Specially, the ability of expansion and quick installation enable one to apply it for distributed power, where the technology is already gaining remarkable attentions for the application. Particularly, leading industrialized nations are focusing on the PEM fuel dell with anticipation that this technology will find their place of applications in the vehicles and homes. In this study, demonstrate the multi physics modeling of a proton exchange membrane(PEM) fuel cell with interdigitated flow field design. The model uses current balances, mass balance(Maxwell-Stefan diffusion for reactant, water and nitrogen gas) and momentum balance(gas flow) to simulate the PEM fuel cell behavior.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.5
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• pp.745-752
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• 2012

This study aims to show the change of Heart Rate Variability(HRV) and Pulse wave velocity(PWV) on menstruation in women at college. Heart Rate Variability(HRV) and Pulse wave velocity(PWV) of 122 women at college were measured at their menstruation and ordinary period. SDNN, RMSSD, SDSD, HRV Index(%), stress resistance and cardiac activity were significantly higher at their menstruation than ordinary period, but Total Power and pNN50(%) were opposite. The automatic nervous system balance and physical stress were decreased in groups without dysmenorrhea than with one. PWV(E-R) and PWV(E-L) were much higher at menstruation than ordinary period. PTT(F-R) and PTT(F-L) were decreased in groups without dysmenorrhea than with severe one. We demonstrated that menstruation can effect on Heart Rate Variability and Pulse wave velocity and dysmenorrhea can cause the imbalance of autonomic nervous system.

• Journal of Drive and Control
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• v.19 no.4
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• pp.104-109
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• 2022

For autonomous driving research using AI, datasets collected from road environments play an important role. In other countries, various datasets such as CityScapes, A2D2, and BDD have already been released, but datasets suitable for the domestic road environment still need to be provided. This paper analyzed and verified the dataset reflecting the Korean driving environment. In order to verify the training dataset, the class imbalance was confirmed by comparing the number of pixels and instances of the dataset. A similar A2D2 dataset was trained with the same deep learning model, ConvNeXt, to compare and verify the constructed dataset. IoU was compared for the same class between two datasets with ConvNeXt and mIoU was compared. In this paper, it was confirmed that the collected dataset reflecting the driving environment of Korea is suitable for learning.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.82-84
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• 2021

Through the smart factory construction project, sensor data such as power, vibration, pressure, and temperature are collected from production facilities, and services such as predictive maintenance, defect prediction, and abnormality detection are developed through data analysis. In general, in the case of manufacturing data, because the imbalance between normal and abnormal data is extreme, an anomaly detection service is preferred. In this paper, FFT method is used to extract feature data of manufacturing data as a pre-stage of the anomaly detection service development. Using this method, we classified the produced products and confirmed results. In other words, after FFT of the representative pattern for each product, we verified whether product classification was possible or not, by calculating correlation coefficient.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.42-51
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• 2007

An AC electrical railroad system has rapidly changing dynamic single-phase load, and at a feeding substation, three-phase electric power is transformed to the paired directional single-phase electric power. There is a great difference in electrical phenomenon between the load of AC electrical railroad system and that of general power system. Electric characteristics of AC electrical railroad's trainload are changed continuously according to the traction, operating characteristic, operating schedule, track slope, etc. Because of the long feeding distance of the dynamic trainload, power quality problems such as voltage drop, voltage imbalance and harmonic distortion my also occur to AC electrical railroad system. These problems affect not only power system stability, but also power quality deterioration in AC electrical railroad system. The dynamic simulation model of AC electrical railroad system presented by PSCAD/EMTDC is modeled in this paper, andthen, it is analyzed voltage drop for AC electrical railroad system both with single-phase distributed STATCOM(Static Synchronous Compensator) installed at SP(Sectioning Post) and without.

• Health Policy and Management
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• v.27 no.4
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• pp.336-346
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• 2017

Background: Due to the asymmetry of information and knowledge and the power of bureaucrats and medical professionals, it is not easy for citizens to participate in health care policy making. This study analyzes the case of the insured organization participating in the Health Insurance Policy Committee (HIPC) and provides a basis for discussing methods and conditions for better public participation. Methods: Qualitative analysis was conducted using the in-depth interviews with the participants and document data such as materials for HIPC meetings. Semi-structured interviews were conducted with purposively sampled six participants from organizations representing the insured in HIPC. The meanings related to the factors affecting participation were found and categorized into major categories. Results: The main factors affecting participating in the decision making process were trust and cooperation among the participants, structure and procedure of governance, representation and expertise of participants, and contents of issues. Due to limited cooperation, participants lacked influence in important decisions. There was an imbalance in power due to unreasonable procedures and criteria for governance. As the materials for meetings were provided inappropriate manner, it was difficult for participants to understand the contents and comments on the meeting. Due to weak accountability structure, opinions from external stakeholders have not been well received. The participation was made depending on the expertise of individual members. The degree of influence was different depending on the contents of the issues. Conclusion: In order to meet the values of democracy and realize the participation that the insured can demonstrate influence, it is necessary to have a fair and reasonable procedure and a sufficient learning environment. More deliberative structure which reflects citizen's public perspective is required, rather than current negotiating structure of HIPC.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.4
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• pp.251-260
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• 2020

A growing interest has emerged in recycling used automobile batteries into energy storage systems (ESSs) to prevent their harmful effects to the environment from improper disposal and to recycle such resources. To transform used batteries into ESSs, composing battery modules with similar performance by grading them is crucial. Imbalance among battery modules degrades the performance of an entire system. Thus, the selection of modules with similar performance and remaining life is the first prerequisite in the reuse of used batteries. In this study, we develop an instrument to measure the impedance spectrum of a battery module to predict the useful remaining life of the used battery. The developed hardware and software are used to apply the AC perturbation to the used battery module and measure its impedance spectrum. The developed instrument can measure the impedance spectrum of the battery module from 0.1 Hz to 1 kHz and calculate the equivalent circuit parameters through curve fitting. The performance of the developed instrument is verified by comparing the measured impedance spectra with those obtained by a commercial equipment.