• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.185-188
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• 2005

This paper proposes a new peak-windowing algorithm with window-length adaptation for peak-to-average power reduction (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. Conventional peak windowing algorithm has advantages, such as moderate system complexity with good spectral shape. However, adjacent peak signals within the length of window functions produce the distortion of signal amplitude since window functions might overap with each other. These undesired characteristics of conventional peak windowing algorithm result in the degradation of BER performance. The proposed algorithm outperforms the conventional one with the aid of window-length adaptation. Simulation results show the efficiency of the proposed algorithm under the environments of WiBro downlink systems.

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1229-1239
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• 2007

In conversion of web pages for mobile devices, since existing web conversion systems eliminate unnecessary objects indiscriminately or only convert the layout of a page, the original intention of a web designer is spoiled. In spite of great advances in device technology, there still remain the problems of limited display sire and insufficient CPU power. In this paper, we propose an adaptation method that minimizes the loss of information and preserves the original intention of a web designer from the visual aspect. In image conversion, the proposed method extracts meaningful information from the background against conventional resizing methods, and performs layout-based conversion for the arrangement of image components. Experimental results show the efficiency of the method on the accuracy and the usability in comparison with existing methods.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.281-286
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• 2019

The study aims to analyze the adaptation strategies and resilience of tobacco farmers to face unfavorable trading system. The research method refers to a qualitative approach with phenomenological models and case studies. The findings revealed tobacco farmers in Jember developed various adaptation strategies and resilience through farmer group organizations, partnerships, self-capacity building and access to financial institutions based on economic, social, cultural, and experience values from various sources and interactions among fellow tobacco farmers. The tobacco trading system, which is left to the market mechanism, results in low bargaining power of farmers, this encourages tobacco farmers to develop various adaptation and survival strategies, namely through collective activities of farmer groups, partnerships and self-development and access to financial institutions. Dealing with the unfavorable tobacco trading system, tobacco farmers do not switch to other commodity farming but adapt and make Jember a center for tobacco production in East Java and Indonesia. From this findings, it suggests to the government as the regulator does not only provide subsidies for tobacco farmers, but also must provide various technical assistance to increase the ability of tobacco farmers. More importantly, regulations must be made benefit tobacco farmers other than corporations so that equality can be enjoyed by tobacco economy players.

• Journal of Power Electronics
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• v.13 no.1
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• pp.122-138
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• 2013

Adaptive control of a peak current mode controlled (PCM) boost converter supplied by a PEM fuel cell is described in this paper. The adaptive controller with reference model and signal adaptation is developed in order to compensate the deviation of the response during the change of the operating point. The procedure for determining the adaptive algorithm's weighting coefficients, based on a combination of the pole-zero placement method and an optimization method is proposed. After applying the proposed procedure, the optimal adaptive algorithm's weighting coefficients can be determined in just a few iterations, without the use of a computer, thus greatly facilitating the application of the algorithm in real systems. Simulation and experimental results show that the dynamic behavior of a highly nonlinear control system with a fuel cell and a PCM boost converter, can fairly accurately be described by the dynamic behavior of the reference model, i.e., a linear system with constant parameters.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.567-579
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• 2016

Several energy saving techniques in cellular wireless networks such as active base station (BS) selection, transmit power budget adaptation and user association have been studied independently or only part of these aspects have been considered together in literature. In this paper, we jointly tackle these three problems and propose an integrated framework, called dynamic cell reconfiguration (DCR). It manages three techniques operating on different time scales for ultimate energy conservation while guaranteeing the quality of service (QoS) level of users. Extensive simulations under various configurations, including the real dataset of BS topology and utilization, demonstrate that the proposed DCR can achieve the performance close to an optimal exhaustive search. Compared to the conventional static scheme where all BSs are always turned on with their maximum transmit powers, DCR can significantly reduce energy consumption, e.g., more than 30% and 50% savings in uniform and non-uniform traffic distribution, respectively.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.1070-1080
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• 2021

This study is a descriptive survey research on social network service addiction tendency and interpersonal relationships on college life adaptation among nursing students. The study period was from October 1 to 4, 2019, the survey was conducted for 228 first and third year nursing students located in G city. The collected data were analyzed with the SPSS 23.0 program using descriptive statistics, ANOVA, Pearson correlation coefficients, and multiple regression. The results of the study showed that there were differences in the subjects' college life adaptation depending on their gender (t=5.26, p<.001), daily average duration of using social network service (F=8.07, p<.001), and friends in real life (F=2.87, p=.037). College life adaptation had a significant correlation with social network service addiction tendency (r=-.31, p<.001) and interpersonal relationships (r=.52, p<.001), and social network service addiction tendency with interpersonal relationships had a significant correlation (r=-.17, p=.011). Factors that affected college life adaptation included interpersonal relationships (𝛽=.477, p<.001), gender (𝛽=-.198, p=.001), and daily average duration of using social network service (𝛽=-.177, p=.003), and the explanatory power of these factors was 37.8%. Based on the results of this study, it is thought that it is necessary to develop a program for a positive interpersonal relationship formation using social network service in order to improve the college life adaptation of nursing students.

• Journal of the Korean Applied Science and Technology
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• v.39 no.6
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• pp.783-791
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• 2022

This Research is a descriptive study conducted to identify the academic stress, interpersonal relationships, and degree of adaptation to college life of nursing students who experienced COVID-19, and to identify factors influencing college life adaptation. The subjects of the research were sophomore students enrolled in 3 university nursing departments in G city. For data analysis, descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis were analyzed. The research result showed a significant negative correlation (r=-.584, p<.001) for academic stress and college life adaptation, and a significant positive correlation (r=.505, p<.001) for interpersonal relationships and college life adaptation. The regression model to confirm the influencing factors on college life adaptation was shown to be significant (F=64.462 p<.001). Academic stress (β=-.542, p<.001), interpersonal relationships (β=.339, p<.001), and housing type (β=.199, p<.001) were found to be significant predictive factors. The explanatory power of these variables was 54.6%. Through the results of this research, it will be possible to provide basic data for developing educational programs to reduce academic stress, improve positive and smooth interpersonal relationships, and improve emotional support for college life adaptation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.8-18
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• 2011

Visible light communication (VLC) using optical sources which can be simultaneously utilized for illumination and communication is currently an attractive option for wireless personal area network. Improving the data rate in optical wireless communication system is challenging due to the limited bandwidth of the optical sources. In this paper, we design the singular value decomposition (SVD)-based multiplexing multi-input multi-output (MIMO) system to support two data streams in optical wireless channels. In order to improve the spectral efficiency, the rate adaptation using multi-level pulse amplitude modulation (PAM) is applied according to the channel condition and we propose the method to allocate the optical power, the offset and the size of modulation scheme theoretically under the constraints of the nonnegativity of the modulated signals, the aggregate optical power and the bit error rate (BER) requirement. The simulation results show that the proposed allocation method gives the better performance than the method to allocate the optical power equally for each data stream.

• Child Health Nursing Research
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• v.7 no.2
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• pp.149-160
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• 2001

The purpose of this study was to explore the health and illness concepts of hospitalized children. The subjects were 129 hospitalized children from 3 to 12 years old in one general hospital. Data were collected through semistructured interviews by authors. This study was conducted from Jun. 1, 2000 to Dec. 31, 2000. Data were coded and categorized by content analysis. The results were as follows : 1. Perceived health concept were physical well-being, food, exercise, powerfulness, emotional stability, obeidence, cleanliness, sleep and ability of social adaptation. 2. Perceived health behavior to maintain health were food, treatment, exercise, cleanliness, obeidence, sleep, emotional stability, power-fulness and psychological stability, physical well-being. 3. Perceived prevention of illness were food, cleanliness, treatment, exercise, obedience, sleep, powerfulness, psychological stability, emotional stability, recreation and ability of social adaptation. 4. Perceived causes of illness were illness, trauma and food. 5. Perceived treatment of illness were treatment, sleep, rest, food, obedience, emotional stability, psychological stability, cleanliness, exercise and powerfulness.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.151-154
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• 2006

In the present paper, hovering performance analyses of proprotor and helicopter rotor blades were performed by using FLUENT software. As a proprotor, TRAM(Tilt Rotor Aeroacoustic Model) was selected and performance analysis was carried out with mesh adaptation for more elaborate solution. As a helicopter rotor blades, two bladed Caradonna and Tung's rotor and four-bladed BO-105 helicopter rotor blades were selected. In case of Caradonna and Tung's rotor, vortex trajectory was compared with experimental data to inspect the vortex convection capability of the present flow solver. For the final case, performance of BO-105 helicopter rotor blades was investigated and compared with experimental data. After performance analyses of proprotor and helicopter rotors, it was shown that the present solver showed reasonable vortex strength, wake geometry and thurst coefficient distributions. But power coefficient was somewhat overestimated about $10%{\sim}15%$ regard less of mesh adaptation.