• Journal of KIISE
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• v.42 no.10
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• pp.1254-1267
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• 2015

Recently, excessive installations of APs have caused WLAN interference, and many techniques have been suggested to solve this problem. The AP aggregation technique serves to reduce active APs by moving station connections to a certain AP. Since this technique forcibly moves station connections, the transmission performance of some stations may deteriorate. The AP transmit power control technique may cause station disconnection or deterioration of transmission performance when power is reduced under a certain level. The combination of these two techniques can reduce interference through AP aggregation and narrow the range of interferences further through detailed power adjustment. However, simply combining these techniques may decrease the probability of power adjustment after aggregation and increase station disconnections upon power control. As a result, improvement in performance may be insignificant. Hence, this study suggests a scheme to combine the AP aggregation and the AP transmit power control techniques in OpenFlow-based WLAN to ameliorate the disadvantages of each technique and to reduce interferences efficiently by performing aggregation for the purpose of increasing the probability of adjusting transmission power. Simulations reveal that the average transmission delay of the suggested scheme is reduced by as much as 12.8% compared to the aggregation scheme and by as much as 18.1% compared to the power control scheme. The packet loss rate due to interference is reduced by as much as 24.9% compared to the aggregation scheme and by as much as 46.7% compared to the power control scheme. In addition, the aggregation scheme and the power control scheme decrease the throughput of several stations as a side effect, but our scheme increases the total data throughput without decreasing the throughput of each station.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.7-9
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• 2006

본 논문에서는 정적인(static) 무선 애드 혹 네트워크상에서 에너지 효율적으로 broadcast하는 문제에 대한 새로운 "Broadcast by iterative Coverage sequence Adjustment with Hitch-hiking (BCAH)" 알고리즘을 제안한다. BCAH는 에너지 효율적인 broadcast알고리즘 중 가장 대표적인 Broadcast Incremental Power(BIP)와 같은 시간 복잡도를 가지면서 BIP에 비해 적은 에너지를 소모해 broadcast를 수행한다. 또한 BCAH는 각 노드의 인접한 노드들의 정보만을 이용해 동작하기 때문에 노드들의 이동성을 고려한 동적인 네트워크에 좋은 확장성을 가진다.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.310-313
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• 1991

This paper reports the characteristics of sparkover discharge in flowing air with variation of Temperature(T). Also, We studied changes of discharge pattern for constant input power by adjustment of the Reynolds number(Re) and T. The essentiales of this paper are as followers. The invaluable equation obtained from this experiment is [%]$\frac{Vs}{Re}$=A+B${\varepsilon}^{c{\cdot}Re}$ where A=10.5 B=120 $C=-3.00{\times}10^{-5}$ Breakdown Voltage for Variation of temperature in static air is given by expression Vs = K (23.98 ${\rho}$d+6.8 ${\sqrt}{{\rho}d}$)[kV] The discharge pattern can be controlled by adjustment of the Reynolds number.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1991.10a
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• pp.28-32
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• 1991

This paper reports the characteristics of sparkover discharge in flowing air with variation of Temperature(T). Also, We studied changes of discharge pattern for constant input power by adjustment of the reynolds number(Re) and T. the essentials of this paper are as followers. The invaluable equation obtained from this experiment is [%] {{{{ { Vs} over {Re } = A·LOG10 Re + B}}}} w here A,B : constant Breakdown Voltage for variation of temperature at 1[m/s] is given by expression Vs = K(23.98 pd + 6.8{{{{ SQRT { pd} }}}}) [kV] where K = 0.331 The discharge pattern can be controlled by adjustment of the Reynolds number

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.727-730
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• 2002

This paper proposes the interference cancellation improvement in smart antenna system by using Applebaum array covariance matrix adjustment. This technique adds the specific adjustable multipliers with both desired signal covariance matrix and interference signal covariance matrices in order to overcome some disadvantages and improve the interference cancellation efficiency of Applebaum array. It is based on the desired and undesired signal power or desired signal-to-interference-plus-thermal noise ratio (SINR). As the result from demonstration, the proposed technique can improve and increase the interference cancellation efficiency in smart antenna better than the conventional technique.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.466-477
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• 2014

Many image hiding schemes based on least significant bit (LSB) transformation have been proposed. One of the LSB-based image hiding schemes that employs diamond encoding was proposed in 2008. In this scheme, the binary secret data is converted into base n representation, and the converted secret data is concealed in the cover image. Here, we show that this scheme has two vulnerabilities: noticeable spots in the stego-image, i.e., a non-smooth embedding result, and inefficiency caused by rough re-adjustment of falling-off-boundary value and impractical base translation. Moreover, we propose a new scheme that is efficient and produces a smooth and high quality embedding result by restricting n to power of 2 and using a sophisticated re-adjustment procedure. Our experimental results show that our scheme yields high quality stego-images and is secure against RS detection attack.

• Journal of Korean Clinical Health Science
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• v.8 no.2
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• pp.1417-1425
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• 2020

Purpose: The purpose of this study was to check the stress, stress and coping ability of nursing college students and to identify factors that influence college life adjustment. Method: This study was a descriptive research study to confirm the correlation between stress, stress response, coping ability, and college life adaptation of nursing college students, and to analyze the factors that influence college life adjustment. The data collection period was from August 17 to 23, 2020, for one week, the researcher directly explains the purpose and purpose of the study to 221 nursing college students nationwide, and online surveys to those who have agreed to participate in the study. The collected data were analyzed using SPSS Win 20.0 program. Results: Adaptation to college was negatively correlated with stress (r=-.285, p<.001), stress response (r=-.258, p<.001), and coping ability (r=.512, p<.001) had a positive correlation. The most significant factor influencing the study subjects' adaptation to college life was coping ability (β=.473, p<.001), followed by stress (β=-.185, p=.002) in the order of The explanatory power of the factors affecting the subject's adaptation to college life was 28.9%. Conclusion: As a result of this study, it means that nursing students' adaptation to college life has less stress and stress response, and higher coping ability increases college life adaptation. The factor that influenced the adjustment to college life was the most significant factor, followed by stress. In order for nursing students to adjust to college life smoothly, it is thought that coping measures to reduce stress and stress responses and overcome them are necessary.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.885-896
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• 2023

This study attempted to identify the relationship between nursing students' adjustment to college life, stress, and major satisfaction, and to identify the factors that affect career decision-making self-efficacy. The study included 298 nursing students from two universities in the region, and data collection was conducted from April 24 to May 9, 2023. Results, It showed a significant negative correlation between college adjustment and stress, and it was found that there was a significant positive correlation between major satisfaction and career decision-making self-efficacy. Major satisfaction was the predictor variable that had the greatest impact on career decision-making self-efficacy, and the explanatory power was found to be 44.8%. This shows that nursing students with high self-efficacy are satisfied with their majors and adapt well to university life if they choose nursing studies. Therefore, there is a need to develop various career exploration and career education programs to enhance career decision-making self-efficacy.

• Journal of Power Electronics
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• v.16 no.1
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• pp.287-296
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• 2016

Conventional maximum power point tracking (MPPT) methods are ineffective under partially shaded conditions because multiple local maximum can be exhibited on power-voltage characteristic curve. This study proposes an improved cuckoo search (ICS) MPPT method after investigating the cuckoo search (CS) algorithm applied in solving multiple MPPT. The algorithm eliminates the random step in the original CS algorithm, and the conception of low-power, high-power, normal and marked zones are introduced. The adaptive step adjustment is also realized according to the different stages of the nest position. This algorithm adopts the large step in low-power and marked zones to reduce search time, and a small step in high-power zone is used to improve search accuracy. Finally, simulation and experiment results indicate that the promoted ICS algorithm can immediately and accurately track the global maximum under partially shaded conditions, and the array output efficiency can be improved.

• Journal of Power Electronics
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• v.12 no.1
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• pp.19-23
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• 2012

This paper presents a practical methodology for realistic simulation on reverse characteristics of Wide Bandgap (WBG) SiC and GaN p-n junctions. The adjustment on certain physic-based model parameters, such as the trap density and photo-generation for SiC junction, and impact ionization coefficients and critical field for GaN junction are described. The adjusted parameters were used in Synopsys Medici simulation to obtain a realistic p-n junction avalanche breakdown voltage. The simulation results were verified through benchmarking against independent data reported by others.