• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.177-187
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• 2003

Active galactic nuclei (AGNs) are distant, powerful sources of radiation over the entire electromagnetic spectrum, from radio waves to gamma-rays. There is much evidence that they are driven by gravitational accretion of stars, dust, and gas, onto central massive black holes (MBHs) imprisoning anywhere from $\~$1 to $\~$10,000 million solar masses; such objects may naturally form in the centers of galaxies during their normal dynamical evolution. A small fraction of AGNs, of the radio-loud type (RLAGNs), are somehow able to generate powerful synchrotron-emitting structures (cores, jets, lobes) with sizes ranging from pc to Mpc. A brief summary of AGN observations and theories is given, with an emphasis on RLAGNs. Preliminary results from the imaging of 10000 extragalactic radio sources observed in the MITVLA snapshot survey, and from a new analytic theory of the time-variable power output from Kerr black hole magnetospheres, are presented. To better understand the complex physical processes within the central engines of AGNs, it is important to confront the observations with theories, from the viewpoint of analyzing the time-variable behaviours of AGNs - which have been recorded over both 'short' human ($10^0-10^9\;s$) and 'long' cosmic ($10^{13} - 10^{17}\;s$) timescales. Some key ingredients of a basic mathematical formalism are outlined, which may help in building detailed Monte-Carlo models of evolving AGN populations; such numerical calculations should be potentially important tools for useful interpretation of the large amounts of statistical data now publicly available for both AGNs and RLAGNs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.236-237
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• 2005

To measure surface roughness and smoothness of semiconducting materials in power cable, we have investigated the formation and growth process of carbon black showed by changing the content of carbon black. The specimens were primarily kneaded in material samples of pellet form for 5 minutes on rollers ranging between 70[$^{\circ}C$] and 100[$^{\circ}C$]. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[kg/cm]. The contents of conductive carbon black were the variable, and their contents were 20, 30 and 40[wt%], respectively. The surface roughness and smoothness of specimens were measured by SEM and AFM. From SEM experimental result, carbon black in specimens formed matrix as a particles. Also we showed growth process of carbon black according to an increment of the content of carbon black. From AFM experimental result, surface roughness of specimens decreased according to an increment of the content of carbon black.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.212-213
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• 2018

The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.218-219
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• 2006

To Smoothness of semiconducting materials in power cable, we have investigated those of semiconducting materials showed by changing the content of carbon black and Carbon Nanotube. Then they were produced as sheets after pressing for 20 minutes at $180^[{\circ}C]$ with a pressure of $200[kg/cm^2]$. The content of conductive carbon black and Carbon Nanotube was the variable, and their contents were 20-40[wt%] and 2-6[wt%] respectively. The smoothness was measured by JSM-6400.

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.44-48
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• 1990

This study was based on 3 necropsies of patients affected with Balantidium coli dysentery from two pig farms. Grossly, the lesions involved the large intestine from cecum to rectum. Many variable-sized ulcers were diffusely scattered on the mucosa of the cecum and the colon which were covered with a necrotic, grayish white, slate black, or black membrane. The mucosa affected reddened and swollen. Microscopically, numerous balantidia penetrated In the mucosa of the colon and there they induced necrosis and desquamation of the epithelial cells, where inflammatory cells such as macrophages, neutrophils, eosinophils, lymphocytes and plasma cells were infiltrated.

• Management & Information Systems Review
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• v.36 no.4
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• pp.103-116
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• 2017

The objective of this study is to examine the effect of the serve employee which is thought as important but has not been studied almost on the response actions to the customer and organization. we tried provide the administrative implications for the black consumer management. This study built a exploratory empirical model that there is causal relationship of the service sector employee on the attitude to the customer and organization on the base of the exploratory consideration. To test hypotheses empirically, the questionnaire data were collected from 262 members of service sector in Busan and was analyzed by using Regression Analysis. Results of empirical analysis are as follow. 1) perceived black consumer behavior which service sector employee has the significant positive effect on the misbehavior to the customer. looking in detail, repetitiveness, insistence, deception, excessiveness are significant positive effect on the misbehavior to the customer. 2) perceived black consumer behavior which service sector employee has the significant positive effect on the misbehavior to the organization. looking in detail, excessiveness only have a positive effect on the misbehavior to the organization. 3) The significance of this study indicates that encourage plays a role as moderating variable influencing the relationship between perceived black consumer behavior and employee misbehavior. Specifically, The significance of this study indicates that encourage plays a role as moderating variable influencing the relationship between perceived excessiveness which the demension of the black consumer behavior and employee misbehavior. Lastly, this study suggested the implication of the result, the limitation and the direction of future study. The results of this study provide suggestion to the company.

• The Research Journal of the Costume Culture
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• v.19 no.3
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• pp.556-564
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• 2011

The purpose of this study was to analyze the effect of the structural properties, the color characteristics and the texture of sight and touch on the tactile preferences for the black fabrics. Male and female university students were asked to evaluate the texture of sight and touch and tactile preference to the nine different black fabrics which were selected on the basis of the previous research results. Data were analyzed by using frequency analysis, mean, factor analysis, t-test, F-test, correlation and regression analysis. The texture of sight and touch for black fabrics was classified into four factors: smoothness, bulkiness, extensibility, firmness. This texture of sight and touch factors showed a significant correlative relationship to the structural properties and color characteristics of the black fabrics. There were significant differences according to black fabrics on the point of texture of sight and touch. The velvet was evaluated the most smooth fabric, while the velvet and fake leather were evaluated the most bulky fabrics. Also, the jersey and lace fabrics were evaluated the most extensible fabrics, while the melton was evaluated as the most firm fabrics. There were significant correlative relationships not only between the structural properties and the texture of sight and touch but also between the color characteristics and the texture for black fabrics. Also, among the structural properties, the color characteristics and the texture of sight and touch of black fabrics, major variable factor of influencing on the tactile preference was turned out to be the texture of sight and touch.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.10
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• pp.443-448
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• 2005

To measure modulus, damping properties and smoothness of semiconducting materials in power cable, we have investigated those of semiconducting materials showed by changing the content of carbon black. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[kg/cm$^{2}$]. The content of conductive carbon black was the variable, and their contents were 20, 30 and 40[wt$\%$], respectively. The modulus and tans were measured by DMA 2980. The ranges of measurement temperature were from -50[$^{\circ}C$] to 100[$^{\circ}C$] and measurement frequency was 1[Hz3. The modulus of specimens was increased according to a increment of a carbon black content. And modulus was rapidly decreased at the glass transition temperature. The tans of specimens was decreased according to a increment of a carbon black content. The smoothness was measured by JSM-6400. EEA resin from SEM measurement was best the dispersion of carbon back in base resin.

• Communications for Statistical Applications and Methods
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• v.29 no.2
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• pp.251-261
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• 2022

As AI has a wide range of influence on human social life, issues of transparency and ethics of AI are emerging. In particular, it is widely known that due to the existence of historical bias in data against ethics or regulatory frameworks for fairness, trained AI models based on such biased data could also impose bias or unfairness against a certain sensitive group (e.g., non-white, women). Demographic disparities due to AI, which refer to socially unacceptable bias that an AI model favors certain groups (e.g., white, men) over other groups (e.g., black, women), have been observed frequently in many applications of AI and many studies have been done recently to develop AI algorithms which remove or alleviate such demographic disparities in trained AI models. In this paper, we consider a problem of using the information in the sensitive variable for fair prediction when using the sensitive variable as a part of input variables is prohibitive by laws or regulations to avoid unfairness. As a way of reflecting the information in the sensitive variable to prediction, we consider a two-stage procedure. First, the sensitive variable is fully included in the learning phase to have a prediction model depending on the sensitive variable, and then an imputed sensitive variable is used in the prediction phase. The aim of this paper is to evaluate this procedure by analyzing several benchmark datasets. We illustrate that using an imputed sensitive variable is helpful to improve prediction accuracies without hampering the degree of fairness much.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.109-113
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• 1997

The purpose of this study is to survey colors of background, marker, and pointer being used in passenger car's display panel, and to suggest ergonomic design guidelines of car's display panel to enhance driver's visibility. An experiment was conducted, in which reading time of display was measured as dependent variable, and colors of black, white, blue and green were selected as background colors of display, and black, white, yellow, and green as marker's colors, and black white, yellow, green and red as pointer's colors. The results showed that reading time of display with white background, yellow marker and pointer was shortest. It was expected that this results could be used as valuable design guidelines in car's display panel.