• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.398-415
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• 2010

The purpose of this paper is to grasp levels of cost burden in pollution treatment by measuring efficiencies and shadow prices by pollutants in Korean cities. The efficiencies and shadow prices of pollutants will be compared for cities divided by Seoul metropolitan area and non-Seoul metropolitan area. Annual shadow prices of NOx, SOx, and PM10 emissions in the cities of Seoul metropolitan area are 0.846, 0.318, 0.816, respectively for 1999-2005. The annual shadow prices in the cities of Non-Seoul metropolitan area are 0.848, 0.272, and 0.789, respectively over the same periods. The shadow prices of SOx showed similar levels between two areas but those of NOx and PM10 of cities in Seoul metropolitan area were higher. NOx emission quantities of both areas have similar increasing patterns because the NOx has mainly increased with augmentation of transportation regardless of Seoul metropolitan and non-Seoul metropolitan areas. It seems that the reason the shadow prices of two pollutants for the cities of Seoul metropolitan area are higher, is because environmental regulation is stronger in the cities of Seoul metropolitan area, the cities of Seoul metropolitan relatively show higher quantities of pollution reduction under given desirable outputs, and generally have industrial sectors with small pollution emission. In the future we need to reduce pollutants in the various respects such as adjustment of overall industry structure, energy consumption pattern, and reviews of arrangement of living space for the cities located on the downward-sloping segment of production frontier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1352-1370
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• 2010

In this paper, we investigated the shadow area of radio programs which are currently being broadcast via FM 102.5 MHz in Jeollabuk-do consisting of 6 cities and 8-guns. The field strength data of FM 102.5 MHz was used with criterion of shadow area. As a result, the field strength of the eastern mountainous area in Jeollabuk-do was very low. We also measured, compared and analyzed the field strength of 102.5 MHz(TBN-Jeonju), 100.7 MHz(KBS) and 99.1 MHz (MBC) in Jeollabuk-do. Based on the field strength data, we tried to find what correlation exists and how much influence is between difference of antenna output power and solution of shadow area. In result, enhancement of antenna output power is not solution in terms of reducing the shadow Area of 102.5 MHz(TBN-Jeonju). In addition, we measured, compared and analyzed the field strength of 102.5 MHz(TBN-Jeonju) and 106.9 MHz(EBS). In fact, the relay stations with 104.1 MHz, 104.9 MHz, 105.3 MHz and 107.5 MHz of EBS FM has a number of FM relay stations in the eastern mountainous area of Jeollabuk-do. As a result, we confirmed that EBS almost did not have shadow area in the eastern mountainous area of Jeollabuk-do based on the field strength data. As in the case of EBS and KBS, we suggest installing TBN-Jeonju FM relay station with the best solution to reducing the shadow area to extend the audible range of TBN-Jeonju.

• Journal of The Korean Association For Science Education
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• v.41 no.5
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• pp.371-390
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• 2021

The purpose of this study is to develop a neuropsychological model for the spatial ability factor and to divide the brain active area involved in the light & shadow problem solving process into the domain-general ability and the domain-specific ability based on the neuropsychological model. Twenty-four male college students participated in the study to measure the synchronized eye movement and electroencephalograms (EEG) while they performed the spatial ability test and the light & shadow tasks. Neuropsychological model for the spatial ability factor and light & shadow problem solving process was developed by integrating the measurements of the participants' eye movements, brain activity areas, and the interview findings regarding their thoughts and strategies. The results of this study are as follows; first, the spatial visualization and mental rotation factors mainly required activation of the parietal lobe, and the spatial orientation factor required activation of the frontal lobe. Second, in the light & shadow problem solving process, participants use both their spatial ability as a domain-general thought, and the application of scientific principles as a domain-specific thought. The brain activity patterns resulting from a participants' inferring the shadow by parallel light source and inferring the shadow when the direction of the light changed were similar to the neuropsychological model for the spatial visualization factor. The brain activity pattern from inferring an object from its shadow by light from multiple directions was similar to the neuropsychological model for the spatial orientation factor. The brain activity pattern from inferring a shadow with a point source of light was similar to the neuropsychological model for the spatial visualization factor. In addition, when solving the light & shadow tasks, the brain's middle temporal gyrus, precentral gyrus, inferior frontal gyrus, middle frontal gyrus were additionally activated, which are responsible for deductive reasoning, working memory, and planning for action.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.63-64
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.135-136
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.321-323
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• 2012

유기 발광 다이오우드는(OLEDs) 자체 발광 소자로써 높은 시야각, 높은 효율, 그리고 빠른 응답속도 등의 장점을 가지고 있어 차세대 디스플레이 및 조명 소자로서 많은 연구가 진행되고 있다. 특히 유기 발광 다이오우드는 차세대 반도체 조명 소자로서 조명의 패러다임을 바꿀 수 있는 기술로 인식되고 있다. 하지만, 유기 발광 다이오우드 조명의 상용화를 위해서는 가격 경쟁력을 갖추는 것이 시급하며, 이를 위해 저가 공정 개발이 필요하다. 본 연구에서는 유기발광 다이오우드 조명 제작에 필수적인 전면 전극 및 절연막 증착 공정을 기존의 노광 공정이 아닌 shadow mask 기술을 적용하여 형성하였다. 먼저 유리 기판 상에 150 nm 두께의 ITO 막을 shadow mask를 이용하여 증착하였다. 기존 공정에서는 노광 및 식각 공정을 이용하여 증착하는 것이 일반적이며, 광학적, 전기적 특성 또한 타 공정 방법에 비해 우수하다. 하지만 일련의 복잡한 공정으로 인해 제조 원가를 상승 시키는 단점이 있다. Fig. 1은 shadow mask를 이용하여 ITO를 증착을 수행한 공정의 모식도이다. ITO 박막 증착 후 표면 거칠기 제어 및 면저항 제어를 위해 O2 plasma 처리와 RTA 공정을 추가 수행하였다. Fig. 2(a)는 플라즈마 처리 및 열처리 공정 수행 후에 측정한 표면 AFM 사진이다. 열처리 및 플라즈마 처리 후에 ITO 박막의 표면 거칠기는 10배 이상 향상되었으며, 이는 유기 발광 다이오우드 조명 소자의 전면 투명 전극으로 사용되기에 적합한 값이다. 또한 전기적 특성 중 하나인 면저항 값은 열처리 및 플라즈마 처리 전/후의 값에서 많은 차이를 보인다. 표면 거칠기가 향상됨에 따라 면저항 값 역시 향상되는 결과를 보여주는데, 표면 처리전후의 면저항 값은 각각 28.17, 13.18 ${\Omega}/{\Box}$이다. 일반적으로 유기 발광 다이오우드의 전면 투명 전극으로 사용되기 위해서는 15 ${\Omega}/{\Box}$이하의 면저항 값이 필요한데, 표면 처리 후의 면저항값들은 이로한 조건을 만족한다. Fig. 3은 shadow mask 기술을 이용하여 절연막까지 형성한 유기 발광 다이오우드 소자의 전자 현미경 사진으로, 기존의 공정을 이용한 경우와 큰 차이는 없으며, 다만 shadow tail이 약 $30{\mu}m$ 정도 발생함을 확인할 수 있다. 절연막의 특성 평가 기준인 누설 전류 밀도는 $10-5A/cm^2$으로 기존의 공정을 이용한 경우에 비해 95% 수준으로서 shadow mask를 이용한 공정이 기존의 노광 및 식각 공정을 이용한 경우에 비해 공정 수는 9개가 단축됨에도 불구하고, 각 증착 박막의 특성에는 큰 차이가 없음을 알 수 있다.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.197-203
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• 2017

The purpose of this study was to measure signal to noise ratio (SNR) according to change of equalization from region of interest (ROI) of heart shadow in chest image. We examined images of chest image of 87 patients in a University-affiliated hospital, Seoul, Korea. Chest images of each patient were calculated by using ImageJ. We have analysis socio-demographical variables, SNR according to images, 95% confidence according to SNR of difference in a mean of SNR. Differences of SNR among change of equalization were tested by SPSS Statistics21 ANOVA test for there was statistical significance 95%(p < 0.05). In SNR results, with the quality of distributions in the order of original chest image, original chest image heart shadow and equalization chest image, equalization chest image heart shadow(p < 0.001). In conclusion, this study would be that quantitative evaluation of heart shadow on chest image can be used as an adjunct to the histogram equalization chest image.

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.20-29
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• 2021

During multi-stage fracturing in a low permeable shale formation, stress interference occurs between the stages which is called the "stress shadow effect(SSE)". The effect may alter the fracture propagation direction and induce ununiform geometry. In this study, the stress shadow effect on the hydraulic fracture geometry and the well productivity were investigated by the commercial full-3D fracture model, GOHFER. In a homogeneous reservoir model, a multi-stage fracturing process was performed with or without the SSE. In addition, the fracturing was performed on two shale reservoirs with different geomechanical properties(Young's modulus and Poisson's ratio) to analyze the stress shadow effect. In the simulation results, the stress change caused by the fracture created in the previous stage switched the maximum/minimum horizontal stress and the lower productivity L-direction fracture was more dominating over the T-direction fracture. Since the Marcellus shale is more brittle than more dominating over the T-direction fracture. Since the Marcellus shale is more brittle than the relatively ductile Eagle Ford shale, the fracture width in the former was developed thicker, resulting in the larger fracture volume. And the Marcellus shale's Young's modulus is low, the stress effect is less significant than the Eagle Ford shale in the stage 2. The stress shadow effect strongly depends on not only the spacing between fractures but also the geomechanical properties. Therefore, the stress shadow effect needs to be taken into account for more accurate analysis of the fracture geometry and for more reliable prediction of the well productivity.

• Journal of Service Research and Studies
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• v.13 no.4
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• pp.1-23
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• 2023

Tablet PCs are gaining increasing popularity in today's context, offering convenience in store operations. However, some customers may have complaints. From the perspective of shadow labor, customers may perceive using tablet PCs as additional tasks, implying that tasks have been transferred from service staff to customers themselves. Therefore, this study aims to investigate the causes of customers' perception of shadow labor when using tablet PCs (perceived difficulty of use and perceived compulsion to use) and how these perceptions can influence their intention to reuse tablet PC ordering services. Additionally, the study examines whether customers' perception of shadow labor is influenced by digital literacy and information overload and investigates the positive impact of benefits arising from using tablet PCs on their perception of shadow labor. This research conducted an online survey through the Chinese survey specialist website "Wenjuanxing," targeting customers who use tablet PCs to place orders in restaurants. After collecting a total of 376 valid data points, demographic characteristics, frequency analysis, reliability analysis, validity analysis, correlation analysis, and regression analysis were conducted using SPSS 24.0. The empirical results from the 376 respondents reveal that digital literacy and information overload affect the perception of shadow labor and also influence the intention to reuse tablet PC ordering services. Furthermore, benefits showed significant moderating effects on these relationships.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.75-91
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• 2023

In this study, we explore the use of ground penetrating radar (GPR) for the nondestructive survey of subsurface conduits, focusing on the challenges posed by multichannel environments. A key concern is the shadow regions created by conduits, which significantly impact survey results. The shadow regions, which are influenced by conduit position and diameter, hinder signal propagation, thereby making detection within these regions challenging. Using finite-difference time-domain numerical analysis, we examined the characteristics of conduit signals, which typically manifest in hyperbolic patterns. Particularly, we investigated three conduit arrangements: horizontal, vertical, and diagonal. Automatic gain control was applied to amplify the signals, enabling the analysis of variations in shadow regions and signal characteristics for each arrangement. In the horizontal arrangement, the proximity of the two conduits resulted in the emergence of a new hyperbolic pattern between the existing conduits. In the vertical arrangement, the lower conduit could be detected using hyperbolic signals on either side, but the detection was challenging when the upper conduit diameter exceeded that of the lower conduit. In the diagonal arrangement, signal characteristics varied based on the position of shadow regions relative to the detection range of the equipment. Asymmetrical signal patterns were observed when the shadow regions fell within the detection range, whereas the signals of the two conduits were minimally impacted when the shadow regions were outside the detection range. This study provides vital insights into accurately detecting and characterizing subsurface multichannel conduits using GPR-a significant contribution to the field of subsurface exploration and management.