• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.40-47
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• 2016

In this paper, a dual mode buck converter with an ability to change mode is proposed, which is suitable particularly for portable device. The problem of conventional mode control circuit is affected by load variation condition such as suddenly or slowly. To resolve this problem, the mode control was designed with slow clock method. Also, when change from the PFM(Pulse Frequency Modulation) mode to the PWM(Pulse Width Modulation) mode, to use the counter to detect a high load. And the user can select mode transition point in load range from 20mA to 90mA by 3 bit digital signal. The circuits are implemented by using BCDMOS 0.18um 2-polt 3-metal process. Measurement environment are input voltage 3.7V, output voltage 1.2V and load current range from 10uA to 500mA. And measurement result show that the peak efficiency is 86% and ripple voltage is less 32mV.

• Bulletin of the Korean Mathematical Society
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• v.58 no.1
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• pp.171-181
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• 2021

The fixing number of a graph G is the smallest order of a subset S of its vertex set V (G) such that the stabilizer of S in G, ��S(G) is trivial. Let G1 and G2 be the disjoint copies of a graph G, and let g : V (G1) → V (G2) be a function. A functigraph FG consists of the vertex set V (G1) ∪ V (G2) and the edge set E(G1) ∪ E(G2) ∪ {uv : v = g(u)}. In this paper, we study the behavior of fixing number in passing from G to FG and find its sharp lower and upper bounds. We also study the fixing number of functigraphs of some well known families of graphs like complete graphs, trees and join graphs.

• Kyungpook Mathematical Journal
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• v.11 no.2
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• pp.213-219
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• 1971

• Kyungpook Mathematical Journal
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• v.18 no.2
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• pp.223-232
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• 1978

• Kyungpook Mathematical Journal
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• v.33 no.2
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• pp.199-203
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• 1993

• KIPE Magazine
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• v.13 no.4
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• pp.38-46
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• 2008

• Kyungpook Mathematical Journal
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• v.17 no.1
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• pp.79-84
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• 1977

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2823-2829
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• 2011

All of the government, private enterprises, and local governments are promoting the spread of electric vehicles to reduce carbon emissions depending on the green growth policy of the government that began in 2009. Due to this background, the prevalence of electric cars is being spread. However, the efficient management and operation through the exchanging information between electric vehicles and charging infrastructure, as well as the development of electric vehicles are essential to disseminate them. In this paper, we present a service framework for exchange of information between electric vehicles and charging infrastructure, and propose a communication method to meet it. To do this, we propose the most appropriate communication method through the performance evaluation by identifying and comparing the existing wireless communication methods can be applied to exchange information between electronic vehicles and EV charging infrastructure.

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.185-195
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• 1994

Using $1024\times1024$ pixels CCD camera of ChungBuk National University Observatory (CBNUO), 62 photometric observations were made on January 11-12, 1993. A time of minimum lights of U Cep was determined as JD Hel 2448999.7274 from our data. On October 21-22 in 1993, CCD photometry in V and R for GW Cephei and V700 Cygni was carried out with 309${\times}$584 pixels cooled CCD system of Behlen Observatory, University of Nebraska-Lincoln (BOUNL) and 168 observations were obtained. From the data times of minimum lights JD Hel 2449282.8485 for GW Cep and JD Hel 2449282.7979 were determined. To developed a new CCD system of CBNUO, the CCD photometry method using at CBNUO is compared with at BOUNL.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.840-860
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• 2023

Aiming at the serious occlusion and slow tracking speed in pedestrian target tracking and recognition in complex scenes, a target tracking method based on improved YOLO v5 combined with Deep SORT is proposed. By merging the attention mechanism ECA-Net with the Neck part of the YOLO v5 network, using the CIoU loss function and the method of CIoU non-maximum value suppression, connecting the Deep SORT model using Shuffle Net V2 as the appearance feature extraction network to achieve lightweight and fast speed tracking and the purpose of improving tracking under occlusion. A large number of experiments show that the improved YOLO v5 increases the average precision by 1.3% compared with other algorithms. The improved tracking model, MOTA reaches 54.3% on the MOT17 pedestrian tracking data, and the tracking accuracy is 3.7% higher than the related algorithms and The model presented in this paper improves the FPS by nearly 5 on the fps indicator.