• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.21-40
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• 2018

In this paper, we propose the distributed robust beamforming design scheme in cognitive two-way amplify-and-forward (AF) relay networks with imperfect channel state information (CSI). Assuming the CSI errors follow a complex Gaussian distribution, the objective of this paper is to design the robust beamformer which minimizes the total transmit power of the collaborative relays. This design will guarantee the outage probability of signal-to-interference-plus-noise ratio (SINR) beyond a target level at each secondary user (SU), and satisfies the outage probability of interference generated on the primary user (PU) above the predetermined maximum tolerable interference power. Due to the multiple CSI uncertainties in the two-way transmission, the probabilistic constrained optimization problem is intractable and difficult to obtain a closed-form solution. To deal with this, we reformulate the problem to the standard form through a series of matrix transformations. We then accomplish the problem by using the probabilistic approach based on two sorts of Bernstein-type inequalities and the worst-case approach based on S-Procedure. The simulation results indicate that the robust beamforming designs based on the probabilistic method and the worst-case method are both robust to the CSI errors. Meanwhile, the probabilistic method can provide higher feasibility rate and consumes less power.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.169-173
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• 2007

During laser irradiation, mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in accelerated stress relaxation. Clinically, laser-assisted cartilage reshaping may be used to recreate the underlying cartilaginous framework in structures such as ear, larynx, trachea, and nose. Therefore, research and identification of the biophysical transformations in cartilage accompanying laser heating are valuable to identify critical laser dosimetry and phase transformation of cartilage for many clinical applications. quasi-elastic light scattering was investigated using Ho : YAG laser $(\lambda=2.12{\mu}m\;;\;t_p\sim450{\mu}s)$ and Nd:YAG Laser $(\lambda=1.32{\mu}m\;;\;t_p\sim700{\mu}s)$ for heating sources and He : Ne $(\lambda=632.8nm)$ laser, high-power diode pumped laser $(\lambda=532nm)$, and Ti : $Al_2O_3$ femtosecond laser $(\lambda=850nm)$ for light scattering sources. A spectrometer and infrared radiometric sensor were used to monitor the backscattered light spectrum and transient temperature changes from cartilage following laser irradiation. Analysis of the optical, thermal, and quasi-elastic light scattering properties may indicate internal dynamics of proteoglycan movement within the cartilage framework during laser irradiation.

• Journal of the Korean Society of Costume
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• v.61 no.4
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• pp.76-91
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• 2011

During the era of Joseon Dynasty when the Confucian ideas were prevailing all over the manners of living, most women were usually living separated in the boudoirs, the isolated living quarters exclusively for women, where they used to do much troublesome needleworks for the traditional kerchiefs and embroideries for which they poured out their souls and hand skills. And therefore, nowadays, such works are deemed much valuable for either formative or artistic point of view, and their legitimate cultural designs are receiving much publicity from a number of mass communications as one of the national competitive powers. Thus, I, the researcher for the subject study, have completed 1-year researching lessons on the traditional kerchief and embroidery of Ms. Hyeon-Hee Kim, the Mater-hand, at Korea Traditional Handicrafts Institute of Korea Cultural Heritage Foundation, and then engaged myself in the creative works relevant to the subject by cultivating the power of understanding to such field, restoring the techniques of the traditional handicrafts, reconstructing them into the modern sensual descriptions, and also trying to apply various transformations and modifications to them.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1574-1580
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• 2008

In this paper, to bring under robust and accurate control of auto-equipment systems which disturbance, parameter alteration of system, uncertainty and so forth exist, neural network controller called dynamic neural processor(DNP) is designed In order to perform a elaborate task like as assembly, manufacturing and so forth of components, tracking control on the trajectory of power coming in contact with a target as well as tracking control on the movement course trajectory of end-effector is indispensable. Also, the learning architecture to compute inverse kinematic coordinates transformations in the Plants of auto-equipment systems is developed and the example that DNP can be used is explained. The architecture and learning algorithm of the proposed dynamic neural network, the DNP, are described and computer simulations are provided to demonstrate the effectiveness of the proposed learning method using the DNP.

• Journal of Korean Society of Rural Planning
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• v.29 no.3
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• pp.69-78
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• 2023

Rural spaces are experiencing an increasing demand for novel functionalities and adaptations driven by technological advancements in agriculture and rural areas. This study aimed to investigate the public perception of rural spaces in the context of evolving agricultural technologies, specifically focusing on photovoltaic power generation, and the ensuing competition among various functions of rural spaces. A survey was conducted with a participant sample of 330, revealing that the majority of respondents prioritize agricultural production as the primary function of farmland. Furthermore, the survey results indicated that the installation of solar panels on farmland is perceived as a complex issue that affects multiple aspects, such as the landscape, local economy, ecological environment, climate change, and income. Additionally, disparities in responses to landscape-related questions were observed based on age, perception of agricultural land functions, and opinions on technological adoption. This finding suggests that the landscape is poised to become a significant factor in future agricultural and rural transformations. The findings of this survey can provide valuable contributions to the preparation of changes catalyzed by advancements in agricultural technology. Moreover, they offer guidance on the key factors that need to be taken into account when introducing new functions to rural spaces.

• Journal of Power Electronics
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• v.17 no.2
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• pp.432-441
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• 2017

Grid voltage feedforward is extensively used for controlling grid-connected converters. However, the conventional voltage feedforward control reduces the stability margins of the converter connected to a high-impedance grid. The effect mechanism of voltage feedforward on the grid-connected converter control under high-inductive conditions of the grid impedance is clearly explained in this study using the equivalent transformations of control block diagrams. Results show that the delay produced by the digital control is the root cause of this effect. An improved voltage feedforward strategy, in which a bandpass filter (BPF) is introduced into the feedforward path, is proposed to strengthen the converter's robust stability against grid impedance variations. The selection method of the BPF's bandwidth is also provided considering the tradeoff between the response speed to the grid voltage sag and the system's robust stability. The converter can work stably over a wide range of the grid impedance through the proposed approach. Simulation and experimental results fully verify the effectiveness of the BPF-based voltage feedforward strategy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.981-988
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• 2022

The intelligent production plant called smart factories that apply information and communication technology (ICT) are collecting data in real time through various sensors. Recently, researches that effectively applying to these collected data have gained a lot of attention. This paper proposes a method for the tool condition monitoring based on the sound signal generated in machining process. First, it not only detects a fault tool, but also presents various tool states according to idle and active operation. The second, it's to represent the power spectrum of the sounds as images and apply some transformations on them in order to reveal, expose, and emphasize the health patterns that are hidden inside them. Finally, the contrast-enhanced PSD image obtained is diagnosed by using CNN. The results of the experiments demonstrate the high discrimination potential afforded by the proposed sound PSD image + CNN and show high diagnostic results according to the tool status.

• The Research Journal of the Costume Culture
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• v.11 no.1
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• pp.20-46
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• 2003

This study analyzes the garment decorations in the history of western costume based on their kinds and techniques, and consider the beginning and the development of costume decoration. The purpose is to promote a historical understanding of modern ornamentation. Based on the theoretical background concerning the origin and purpose of costume decoration, its symbolism and its relationship with images, this study classified the techniques and kinds of ornament and considered each costumes by their decoration. 1. The ornament was originated from the primitive custom of coloring the skin for the purpose of protecting the body, symbolizing the tribe, indicating the class, and threatening the enemies. As this custom changed into the decoration on the body as a form of tattoos or physical transformations, the practice of ornament seems to begin as a display of one's authority and wealth as well as a human instinct to decorate oneself beautifully. 2. The basic purpose of ornament is to look attractive by decorating oneself with ornaments. Addition of decorative design to the garment tends to complement the practical aspects of the whole clothing, and elevate its value and originality. 3. From the past, ornament has been used as a symbol of wealth and status. Originated from the desire to display one´s authority and power and to receive respect from others, the people's interest in ornament have rising. 4. The kinds and techniques of ornament can be classified into the structural and applied decorations. The former is decorating a part of a garment, such as the neckline, cellar, cuffs, or pockets. The latter includes braids, laces and embroideries. These ornament are diverse in their details and techniques, and should consider both functional aspects of clothing and its decorative functions emphasizing the aesthetic expressions. In the above considerations, we can see that costume ornament was most splendid in the premodern times and it was the simplest in the ancient times. And we also saw the possibility that decorative techniques could be created almost limitlessly.

• Journal of architectural history
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• v.2 no.1 s.3
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• pp.9-24
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• 1993

The objective of this study is to describe more positively and concretely the entity of traditional village through the quantitative and scientific analysis process using positive data. Dan-Gye, a traditional village in San-Cheong, has been populated since more than 500 years ago because of its ideal conditions for settlement. In this study, the fluctuations on the numbers of households in Dan-Gye were analyzed from the first settlement era to the present, and the transformations of housing sites and roads since 1913 were also analyzed. The results are as follows. 1) The village Dan-Gye has a history of more than 500 years, and the first inhabitants were the Ryus. As time went by, the Ryus' power became weak gradually, but the powers of the Kwons and the Parks who had flowed later into this village became prosperous to make up a prominent family village in the late period of Cho-Sun dynasty. Such powers had reached the peak in the early period of Japanese occupation, and although the powers became weak gradually after that time, those two families have overwhelmed other families in population and possession of large houses until now. But as the confucianism in every-day life fell off and the inhabitants moved to cities, the existence of a family community became meaningless. 2) The Kwons and the Parks have possessed the large parts of the village's housing sites. As time went by, the sites have been divided and fields have been changed to housing sites for the increasing families, and such division and change have been made chiefly on perimeter areas. 3) The characteristics of the road in Dan-Gye where traditional roads existed began to be destroyed by Japanese construction of new roads, and such destruction has continued due to the bank construction after a flood and the road constructions after 1970s.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.157-166
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• 2016

In this paper, a new sag and peak voltage detector is proposed for a single-phase inverter using delta square operation. The conventional sag detector is from a single-phase digital phase-locked loop (DPLL) that is based on d-q transformations using an all-pass filter (APF). The d-q transformation is typically used in the three-phase coordinate system. The APF generates a virtual q-axis voltage component with a 90° phase delay, but this virtual phase cannot reflect a sudden change in the grid voltage at the instant the voltage sag occurs. As a result, the peak value is drastically distorted, and it settles down slowly. A modified APF generates the virtual q-axis voltage component from the difference between the current and the previous values of the d-axis voltage component in the stationary reference frame. However, the modified APF cannot detect the voltage sag and peak value when the sag occurs around the zero crossing points such as 0° and 180°, because the difference voltage is not sufficient to detect the voltage sag. The proposed algorithm detects the sag voltage through all regions including the zero crossing voltage. Moreover, the exact voltage drop can be acquired by calculating the q-axis component that is proportional to the d-axis component. To verify the feasibility of the proposed system, the conventional and proposed methods are compared using simulations and experimental results.