• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.115-115
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• 2007

PRAM (Phase Change Random Access Memory)은 상변화 물질의 비저항 차이를 이용한 메모리 소자로 차세대 비휘발성 메모리로 주목받고 있다. 현재 상변화 물질로 사용되고 있는 $Ge_2Sb_2Te_5$ 박막은 결정질 상태에서 저항이 낮아 RESET 동작에서 많은 전력이 소비되고 메모리의 고집적의 어려움이 있다. 이러한 문제를 해결하기 위해 상변화 물질의 개선과 소자 구조의 개선 등의 새로운 접근이 시도되고 있다. 본 연구에서는 $Ge_2Sb_2Te_5$ 박막의 전기적 특성을 개선하기 위해서 이종 원소인 질소를 첨가한 N-doped $Ge_2Sb_2Te_5$ 박막에 대한 특성을 살펴 보았다. $SiO_2$/Si 기판 위에 100 nm 두께의 박막을 D.C. magnetron sputter 방법으로 증착하여, 질소 분위기 $100^{\circ}C{\sim}300^{\circ}C$온도 구간에서 열처리하였다. 열처리에 따른 박막 특성을 관찰하기 위해 면저항 측정, XRD, TEM 분석을 통해 박막 특성을 관찰하였다. 면저항 측정과 XRD peak 분석을 통해 $Ge_2Sb_2Te_5$ 시스템에 비하여 N-doped $Ge_2Sb_2Te_5$ 시스템의 결정화 온도가 상승하였음을 확인하였다. 면저항은 첨가된 질소의 조성이 증가할수록 증가하였고, FCC 상에서 HCP 상으로의 상변화 온도 역시 증가하였다. 첨가된 질소가 $Ge_2Sb_2Te_5$, 박막의 결정 성장을 억제하였고, 상대적으로 높은 저항을 가지고 안정한 FCC상을 고온 열처리 이후에도 유지하였다. 질소 첨가를 이용한 상변화 물질의 열안정성 향상과 저소비전력 구동을 통해 향후 고집적 상변화 메모리에의 적용이 가능하다.

• Korean Journal of Remote Sensing
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• v.24 no.6
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• pp.631-639
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• 2008

This study presents an approach to synthesize hyperspectral images of lower resolution at a higher resolution using the high resolution images acquired from a sensor of commercial satellites. The proposed method was applied to the reconstruction of EO-1 Hyperion images using the images acquired from IKONOS sensor. Based on the FitPAN-Mod pansharpening technique (Lee, 2008b), the hyperspectral images of 30m resolution were reconstructed at 1m resolution of IKONOS panchromatic image. In this study, the synthesized hyperspectral images of 50 bands, whose wavelengths range in the wavelength of panchromatic sensor, were generated from the three stages of high resolution reconstruction using FitPAN-Mod. The experimental results show that the proposed method effectively integrates the spatial detail of the panchromatic modality as well as the spectral detail of the hyperspectral one into the synthesized image. It indicates the proposed method has a potential as a technique to produce alternative images for the images that would have been observed from a hyperspectral sensor at the high resolution of commercial satellite images.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.85-92
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• 2022

In this paper, we propose a technique that can express low-resolution hair and fur simulations in high-resolution without noise using ConvNet and geometric images of strands in the form of lines. Pairs between low-resolution and high-resolution data can be obtained through physics-based simulation, and a low-resolution-high-resolution data pair is established using the obtained data. The data used for training is used by converting the position of the hair strands into a geometric image. The hair and fur network proposed in this paper is used for an image synthesizer that upscales a low-resolution image to a high-resolution image. If the high-resolution geometry image obtained as a result of the test is converted back to high-resolution hair, it is possible to express the elastic movement of hair, which is difficult to express with a single mapping function. As for the performance of the synthesis result, it showed faster performance than the traditional physics-based simulation, and it can be easily executed without knowing complex numerical analysis.

• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.519-529
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• 2003

This study investigated the characteristics of verbal interactions of various small groups based on previous achievement in paired think-aloud problem solving. Two classes of a high school were assigned to the homogeneous and heterogeneous groups, and taught on chemistry. Students from homogeneous groups (high${\cdot}$high, mid？id) and heterogeneous groups (high${\cdot}$mid, high${\cdot}$low) were selected, and their algorithmic problem solving on chemical equation and stoichiometry were audio/video taped. In high${\cdot}$high group, solver's 'require agreement' and listener 'agree' were frequently exhibited. On the other hands, listener's 'point out' and solver's 'modify' were frequently exhibited in mid${\cdot}$mid group, which was also observed in the heterogeneous groups (high${\cdot}$mid, high${\cdot}$low). Many verbal interactions were analyzed to be in symmetrical type. In this type, 'require agreement-agree' of high${\cdot}$high group was the most frequent. 'problem solving-agree' of high${\cdot}$high group was the most frequent in the solver-dominant type, while 'point out-modify' of high${\cdot}$low group in the listener-dominant type. The verbal behaviors related to the solving stage were frequently observed, but there were few related to the reviewing stage.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.12-18
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• 2006

This paper presents a method to extract a good high-resolution image from a low-resolution video in an automatic manner. Since a high-resolution image reconstruction method utilizing several low-resolution input images works better than a conventional interpolation method utilizing single low-resolution input image only if the input images are well registered onto a common high-resolution grid, low-resolution input images should be carefully chosen so that the registration errors can be carefully considered. In this paper, the statistics obtained from the motion-compensated low-resolution images are utilized to evaluate the feasibility of the input image candidates. Maximum motion-compensation error is estimated from the high-resolution image observation model. U the motion-compensation error of the input image candidate is greater than the estimated maximum motion-compensation error, the input image candidate is discarded. The number of good input image candidates and the statistics of the motion-compensation errors are used to choose final input images. The final input images chosen from the input image selection block are given to the following high-resolution image reconstruction block. It is expected that the proposed method is utilized to extract a good high-resolution image efficiently from a low-resolution video without any user intervention.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.142-147
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• 1997

Purpose: To compare the effectiveness of the in-phase (IP) sequence and the opposed-phase (Op) sequence in the detection of focal hepatic lesions in the single breath-hold hepatic MR imaging with fast gradient T1-weighted pulse sequences. Materials and Methods: IP and OP T1-weighted breath-hold imaging was performed using fast gradient echo sequences in 45 patients referred for known focal hepatic lesions, in which 78 lesions were detected. Three blind readers independently reviewed the images for lesion detectability. The signal-to-noise ratio (SNR) of the liver, the lesion-to-liver contrast-to-noise ratio (CNR) and the liver-to-spleen CNR were also compared. A consensus was reached by three readers to determine which sequence is better in image quality. Results: On OP images, 61(78%), 61(78%), and 63(89%) lesions were correctly identified for reader 1, 2 and 3, respectively. On IP images, 66(85%), 65(83%), and 65(93%) lesions were detected for each reader, respectively. When two image sets were combined, 71(91 %), 69(88 %), and 76(97%) lesions respectively were detected for each reader. In cases of hepatocellular carcinoma, liver-to-Iesion CNR was greater on the OP images(p (0.05), but in other lesions significant difference was not demonstrated. Liver-to-spleen CNR was higher on OP images(p ( 0.1), but the SNR of the liver was higher on the IP images. Conclusion: Use of both IP and OP imaging can be helpful to avoid erroneous missing of some focal hepatic lesions.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.270-274
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• 2010

Purpose: Here we present tardy ulnar nerve palsy cases that were caused by the anconeus epitroch-learis muscle. Materials and Methods: A 37 year old female patient presented with tardy ulnar nerve palsy findings for the elbow. During surgery, an atypical anconeus epitrochlearis muscle was observed, which originated from the triceps aponeurosis and inserted into the medial intermuscular septum. Muscle resection, nerve decompression and ulnar nerve anterior transposition were done. A 35 year old male patient presented with tardy ulnar nerve palsy findings for the elbow. During surgery, a typical anconeus epitrochlearis muscle was found. Muscle resection, nerve decompression and ulnar nerve anterior transposition were done. Results and Conclusion: Tardy ulnar nerve palsy can be associated with and caused by either an atypical or a typical anconeus epitrochlearis muscle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.339-351
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• 2021

This study was designed to classify the parents' and their children's perception of contact frequency and to examine differences between career development competency and academic outcomes according to perceptional differences. Data of elementary school to high school students from the School Career Education Survey (2018) were used, and latent profile analysis (LPA) was utilized to explore the parents' and their children's perception of contact frequency. The perception of parents' and their children's contact frequency was classified into six groups in elementary and middle school and seven groups in high school. Career development competency (self-understanding and social competence, job understanding, career exploration, and career design and reparation) and academic outcomes (autonomous learning, motivation, and self-directed learning) of classified groups related to contact frequency significantly differed. In general, groups who reported a higher perception of contact frequency by children than parents showed higher vocational identity and better academic outcomes. This result implies that perceived contact frequency between parents and children can differ by school level, and its differences can be related to career development competency and academic outcomes of adolescents.

• 한국노년학
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• v.29 no.3
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• pp.1001-1024
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• 2009

This study investigates what older adults have image of older adult with relation to their self-identity. Fourteen participants are interviewed in this study. The main findings are as follows. Their response to image of older adult is divided in the form of 'denial' and 'accommodation' about social images of older adults. 'Denial' has 'total denial' and 'selective denial' while 'accommodation' includes 'acceptive accommodation', 'selective accommodation' and 'unwilling accommodation'. 'Total denial' indicates that the participants describe older adults very negatively, and they regard themselves as a person who is totally different from the older person they describe. 'Selective denial' represents that the participants have two types of older adults: negative and positive. They describe that they are close to the positive type of older adults themselves although they do not admit that they are older adults. 'Acceptive accommodating' does not describe older adults negatively, and they identify themselves as older adults. 'Selective accommodating' are very similar to 'selective denial' although the former differs from the latter in that they accept that they are older adults. 'Selective accommodating' also includes negative and positive types of older adults, and this type of participants admit that they are older adults, and believe that they belong to the positive type. In contrast to 'acceptive accommodating', 'unwilling accommodating' describes older adults very negatively. However, the participants belonging to 'unwilling accommodating' comes to accept that they are older adults due to irresistible realities.

• Korean Journal of Materials Research
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• v.6 no.3
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• pp.305-308
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• 1996

YxFe2-xO3(x=0.82)의 결정상 변환을 상온에서의 x선회절과 온도구간 80-541K에서의 Mossbauer 분광 방법에 의해서 연구하였다. Xtjs 회절선은 시료가 orthorhombic 결정상과 garnet 결정상이 공존하고 있으며, 공존비는 실험오차 범위내에서 garnet 구조가 orthorhombic 구조보다 우세함을 보인다. 공존상중에서 garnet 구조의 자기상 변환온도는 536$\pm$5 K로 결정하였다. Debye 모형을 이용한 Mossbauer 스펙트럼의 recoil-free fration 분석결과는 garnet 결정상내의 d자리나 a자리에 vacancy의 존재 가능성을 시사한다. 부가적으로 시료가 포함하는 각 결정상의 Debye 특성온도를 결정하였다.