• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.34-41
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• 2000

Purpose: To evaluate the clinical usefulness of diffusion weighted MR imaging(DWI) in the differential diagnosis of brain tumors. Materials and methods: DWI and conventional MR images of nineteen patients with brain tumors(10 metastatic tumors, 4 high grade gliomas, 4 low grade astrocytomas, one oligodendroglioma)were obtained on 1.5T unit. DWI was obtained using single shot spin echo planar imaging with b-value near 1000. We analyzed the signal intensities of lesions including solid portion, necrotic or cystic portion and peritumoral edema of brain tumors (classified five grades comparison with the signal intensities of brain parenchyma and CSF)and calculate the SIR(signal intensity ratio)of lesions to the contralateral normal brain parenchyma. We analyzed statistically the signal intensities and SIR of tumors using independence T test. Results: In solid portions of tumors, all the metastatic tumors and high grade gliomas showed high signal intensities, but low grade astrocytomas and oligodendroglioma showed iso or slight high signal intensities to the normal brain parenchyma. The SIR of solid portion has positive correlation with malignant pot ential(metastatic tumors 1.52, high grade gliomas 1.38, low grade astrocytomas 1.16, oligodendroglioma 1.31)(p < 0.05). In peritumoral edema where seen in 14 tumors, seven of 10 metastatic tumors and two of 4 high grade gliomas showed iso signal intensities, whereas edemas in other 5 brain tumors showed hyperintense to the normal brain parenchyma. The SIRs of peritumoral edemas in metastatic tumors (1.14) was lower than high grade gliomas(1.31),but statistically insignificant. The SIR of cystic or necrotic portion of brain tumors was 0.63. In non enhancing solid portions, three of six cases showed hyperintense to the adjacent peritumoral edema. Conclusion: On DWI, the signal intensities of solid portion has positive correlation with malignant potential, and perilesional edema of brain tumors appear various signal intensities owing to "T2 shine through effect" and the extensiveness of vasogenic edema. Another merit using DWI on the evaluation of brain tumors is to improved better delineation of tumor margins from the adjacent edemas, especially at the non enhancing solid portion of the tumors.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.591-602
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• 2021

Acute ischemic stroke(AIS) should be diagnosed within a few hours of onset of cerebral infarction symptoms using diagnostic radiology. In this study, we evaluated the clinical usefulness of SVD and the Bayesian algorithm to measure the volume of cerebral infarction using computed tomography perfusion(CTP) imaging and magnetic resonance diffusion-weighted imaging(MR DWI). We retrospectively included 50 patients (male : female = 33 : 17) who visited the emergency department with symptoms of AIS from September 2017 to September 2020. The cerebral infarct volume measured by SVD and the Bayesian algorithm was analyzed using the Wilcoxon signed rank test and expressed as a median value and an interquartile range of 25 - 75 %. The core volume measured by SVD and the Bayesian algorithm using was CTP imaging was 18.07 (7.76 - 33.98) cc and 47.3 (23.76 - 79.11) cc, respectively, while the penumbra volume was 140.24 (117.8 - 176.89) cc and 105.05 (72.52 - 141.98) cc, respectively. The mismatch ratio was 7.56 % (4.36 - 15.26 %) and 2.08 % (1.68 - 2.77 %) for SVD and the Bayesian algorithm, respectively, and all the measured values had statistically significant differences (p < 0.05). Spearman's correlation analysis showed that the correlation coefficient of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was higher than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (r = 0.915 vs. r = 0.763 ; p < 0.01). Furthermore, the results of the Bland Altman plot analysis demonstrated that the slope of the scatter plot of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was more steady than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (y = -0.065 vs. y = -0.749), indicating that the Bayesian algorithm was more reliable than SVD. In conclusion, the Bayesian algorithm is more accurate than SVD in measuring cerebral infarct volume. Therefore, it can be useful in clinical utility.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.17-24
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• 2014

Purpose : To determine whether high-resolution contrast-enhanced three dimensional imaging with spoiled gradient-recalled sequence (HR-CE 3D-SPGR) plays a meaningful role in the assessment of intracranial vertebral artery (ICVA) and posterior inferior cerebellar artery (PICA) in lateral medullary infarction (LMI). Materials and Methods: Twenty-five patients confirmed with LMI were retrospectively enrolled with approval by the IRB of our institute, and 3T MRI with HR-CE 3D-SPGR and contrast-enhanced magnetic resonance angiography (CE-MRA) were performed. Two radiologists who were blinded to clinical information and other brain MR images including diffusion weighted image independently evaluated arterial lesions in ICVA and PICA. The demographic characteristics, the area of LMI and cerebellar involvement were analyzed and compared between patients with arterial lesion in ICVA only and patients with arterial lesions in both ICVA and PICA on HR-CE 3D-SPGR. Results: Twenty-two of twenty-five LMI patients had arterial lesions in ICVA or PICA on HR-CE 3D SPGR. However twelve arterial lesions in PICA were not shown on CE-MRA. Concurrent cerebellar involvement appeared more in LMI patients with arterial lesion in ICVA and PICA than those with arterial lesion in ICVA alone (p = 0.069). Conclusion: HR-CE 3D-SPGR can help evaluate arterial lesions in ICVA and PICA for LMI patients.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.459-468
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• 2022

This study searched and analyzed news and information on the Korea-U.S. Summit to explore which political agenda is spreading among Korean newspapers and social media. The result of the analysis revealed that, on the one hand, the conservative-leaning newspaper, Chosunilbo, covered the unresolved issue between two countries. The principal source of news was the opposition party. On the other hand, the progressive-leaning newspaper, Kyunghany Sinmun, highlighted President Moon's visit to the United States and described the visit to the United States as an achievement. In this paper, the principal source of news is the ruling party. Both conservative and the progressive newspapers did not present a negative view of the United States. In the case of Chosunilbo, it mentioned that foreign policy priority of President Biden is human rights in North Korea. If the two countries do not solve this issue, the relationship between Korea and the United States will not develop further. Second, I searched YouTube videos about the Korea-U.S. summit and conducted a network analysis to understand the influence of YouTube videos and explore their relationship the each other. The results of the analysis revealed that the 10 most influential videos portrayed the Moon government positively. These videos held the achievement of the visit to the United States in highly esteem and framed it positively, similarly to the progressive newspaper.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.55-62
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• 2010

While the broadband network and multimedia technologies have been developing, the commercial market of digital contents also has been widely spreading with recently starting IPTV. As the IPTV services are getting to be generalized and popularized, the contents illicit copying and distribution of copyright meterials tends to draw more attentions. So we need a right service system that can protect contents and copyright using watermark inserting. Until now, the conventional protection and authentication system is taking advantages of merits both in CAS and DRM. But this system can not protect the contents when acquiring them from TV output using A/D convertor. So we apply watermark method using HSI color space against contents illicit copying. And for distribution of copyright materials. we compound unique settop ID and copyrighter's ID to make new ID that is watermark. When inserting watermark, we use the watermark for copyright protection and authentication. So we can protect copyright and identify last settop's user in illicit distribution. we design download based IPTV contents protection and authentication system using HSI watermark method.

• Journal of Digital Convergence
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• v.13 no.3
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• pp.31-36
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• 2015

The Many universities and educational institutions have focused on shifting education paradigm into smart learning using high-tech devices and internet as the level of technology has growing rapidly in every society. Especially, cyber universities and open universities in Korea are trying to develop educational network system and infrastructure corresponding to new convergence technology environment. Therefore, the purpose of this study is to introduce clouded based education system in order to suggest an effective way of using new educational learning system. This study shows the case of Hangout learning system used in K University in Korea to suggest a new educational learning model for real-time lecture and cloud based service platform for improving educational learning environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.29-29
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• 2016

새만금호의 목표수질 달성과 지속가능한 관리를 위해서는 비점오염 관리의 필요성이 강조되고 있다. 특히, 새만금호 상류 유역은 농경지 비율이 38%로서 높아 농업활동에서 유래하는 농업 비점오염원의 효과적인 관리가 필요하다. 이를 위해서는 농업비점오염 저감기술의 개발하는 물리적 기술적 접근만이 아니라 농업인과 지역주민의 참여와 함께 행정적인 지원을 포함하는 사회 경제 문화적 접근을 포함하는 통합적인 접근 즉, 거버넌스가 요구된다. 이러한 거버넌스를 새만금유역의 농업비점 관리에 적용하려는 노력의 일환으로 "새만금유역 농업비점오염관리 거버넌스구축 사업모델 개발"에 대한 연구를 2015년부터 2016년까지 2년간 추진하게 되었다. 본 연구의 목적은 농업비점오염 관리를 위한 거버넌스 구축과 운영에 필요한 요소들을 도출하고 각각의 요소별 추진 프로세스를 개발하고 최종적으로 이를 상호 연계하여 운영하는 기법을 개발하는 것이다. 농업비점오염관리 거버넌스 구축의 접근 방향으로는 신규구축형과 기존정책사업연계형으로 접근하는 것이 바람직 할 것으로 판단된다. 거버넌스 시스템은 참여단위와 행정단위, 그리고 이것을 연계 지원하는 '중간지원조직'의 다층적 거버넌스 구조로 제안하였다. 참여단위 거버넌스는 공동체단위와 개별 농가단위의 참여 프로그램으로 설계하였다. 특히, 참여단위 거버넌스의 지속성을 유지하기 위해서 커뮤니티비즈니스 육성이 필요할 것으로 나타났다. 1차년도(2015년)에는 신규구축형을 중심으로 진행을 위하여 전라북도 부안군 백산면 용계리를 연구대상 지구로 선정하였다. 참여단위 거버넌스 구축을 위하여 연구대상 지구에서 우리 마을과 물 이야기, 우리마을회의 등 통하여 주민이 생각하는 지역의 역사와 문화 등 잠재자원을 발굴하였고, 이를 바탕으로 침체된 마을 공동체를 마을길을 연결하여 다시 활성화 하고, 물이 흐르는 마을도랑으로 가꾸고, 단절된 이웃간 마음을 연결하기 위한 "마을길-물길-마음길 연결" 커뮤니티 비즈니스 프로젝터를 도출하였다. 이러한 거버넌스구축 프로그램의 정보의 공유와 확산을 위하여 커뮤니티 비즈니스 안내판을 설치하고, 마을소식지(청파)를 제작배부하고 거버넌스구축 과정을 담은 마을영상다큐 제작을 진행하였다. 2차년도에는 커뮤니티 비즈니스 심화과정을 운영하고자 한다. 본 연구의 결과는 앞으로 농촌지역의 비점오염관리를 위한 거버넌스구축 등 정책 및 제도개선에 도움이 될 것으로 기대된다.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.724-733
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• 2022

The purpose of this paper is to explain the recipient's psychology, which results from the operation of media, from the perspective of the fluctuation between immersion and contemplation. Media allow to perceive and speculate about specific objects or meanings. In addition, the media perform the function of expanding or changing the objects of perception and thought. McLuhan or Luhmann's media theory emphasized this function of changing the state of perception by inducing a contemplative attitude. This notion is exemplified by interpretation of the visual media history. In this paper, the cases of film and computer game are discussed. In particular, it is considered that VR media causing strong immersion have also developed in a way that allows recipients to contemplate an virtually constructed reality. The commercialization of Tilt Brush and the experimentation of VR painting artwork are the examples for this dual development.

• Journal of Platform Technology
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• v.11 no.4
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• pp.3-12
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• 2023

In the post-COVID era, the importance of quarantine measures is greatly emphasized, and accordingly, research related to the detection of mask wearing conditions and prevention of other infectious diseases using deep learning is being conducted. However, research on the detection and tracking of visitors to cultural facilities to prevent the spread of diseases is equally important, so research on this should be conducted. In this paper, a convolutional neural network-based object detection model is trained through transfer learning using a pre-collected dataset. The weights of the trained detection model are then applied to a multi-object tracking model to monitor visitors. The visitor detection model demonstrates results with a precision of 96.3%, recall of 85.2%, and an F1-score of 90.4%. Quantitative results of the tracking model include a MOTA (Multiple Object Tracking Accuracy) of 65.6%, IDF1 (ID F1 Score) of 68.3%, and HOTA (Higher Order Tracking Accuracy) of 57.2%. Furthermore, a qualitative comparison with other multi-object tracking models showcased superior results for the model proposed in this paper. The research of this paper can be applied to the hygiene systems within cultural facilities in the post-COVID era.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.278-283
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• 2020

Central sleep apnea (CSA) is characterized by respiratory failure of at least 10 seconds without any effort of the chest and abdomen in the absence of upper airway resistance during sleep. In this case, the patient experiences respiratory failure that does not meet the CSA diagnostic criteria and CSA symptoms. Magnetic resonance imaging diffusion-weighted imaging (MRI DWI) scans revealed a lateral medullary infarction. Continuous positive airway pressure (CPAP) was applied as a primary treatment for CSA and respiratory failure. During the titration of CPAP, the apnea-hypopnea index (AHI) and arousal index (AI) were worse than the results before its use (AHI: 42.5/hr→82.8/hr, AI: 21.7/hr→40.8h). As a result, adaptive servo-ventilation (ASV) was chosen as the secondary treatment. Compared to the night-polysomnography results before the ASV treatment, the AHI improved (42.5/hr→8.6/hr). Therefore, ASV is a potential treatment for CSA and respiratory failure in these patients.