• Journal of Digital Contents Society
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• v.18 no.5
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• pp.911-921
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• 2017

The purpose of this study was to investigate the semantic network analysis to understand image contents and to examine the degree to which words, word clusters contributed to the formation of semantic map within image contents. For this research, from 1993 until 2016 the field of the image contents were collected for a total of 2,624 cases papers. The word appeared in Title analyzed the social network by using the R program of Big Data. The results were as follows: First, Research on 'education' in the field of image contents has decreased. Second, the role of 'media' in the field of image contents is changing. Finally, It is a change in the status of 'contents' in the field of image contents.

• The Journal of Advanced Prosthodontics
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• v.2 no.1
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• pp.7-13
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• 2010

Although most researchers agree that platelet-rich plasma (PRP) is a good source of autogenous growth factors, its effect on bone regeneration is still controversial. The purpose of this study was to evaluate whether increasing angiogenic factors in the human PRP to enhance new bone formation through rapid angiogenesis. MATERIAL AND METHODS. In vitro, the human platelets were activated with application of shear stress, $20\;{\mu}g/ml$ collagen, 2 mM $CaCl_2$ and 10U thrombin/$1\;{\times}\;10^9$ platelets. Level of vascular endothelial growth factor (VEGF) and platelet microparticle (PMP) in the activated platelets were checked. In the animal study, human angiogenic factors-enriched PRP was tested in 28 athymic rat's cranial critical bone defects with $\beta$-TCP. Angiogenesis and osteogenesis were evaluated by laser Doppler perfusion imaging, histology, dual energy X-ray densinometry, and micro-computed tomography. RESULTS. In vitro, this human angiogenic factors-enriched PRP resulted in better cellular proliferation and osteogenic differentiation. In vivo, increasing angiogenic potential of the PRP showed significantly higher blood perfusion around the defect and enhanced new bone formation around acellular bone graft material. CONCLUSION. Angiogenic factor-enriched PRP leads to faster and more extensive new bone formation in the critical size bone defect. The results implicate that rapid angiogenesis in the initial healing period by PRP could be supposed as a way to overcome short term effect of the rapid angiogenesis.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.319-325
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• 2015

While the conventional personal protective equipments (PPEs) covers a variety of devices and garments such as respirators, turnout gear, gloves, blankets and gas masks, several electronic devices such as personal alert safety system (PASS) and heads-up displays in the facepiece have become a part of firefighters personal protective equipments through past several years. Furthermore, more advanced electronic sensors including location traking sensor, thermal imaging caerma, toxic gas detectors, and even physiological monitoring sensors are being integrated into ensemble elements for better protection of firefighters from fire sites. Despite any electronic equipment placed on the firefighter must withstand environmental extremes and continue to properly function under any thermal conditions that firefighters routinely face, there are no specific criteria for these electronics to define functionability of these devices under given thermal conditions. Although manufacturers provide the specifications and performance guidelines for their products, their operation guidelines hardly match the real thermal conditions. Present study overviews firefighter's fatalities and thermal conditions that firefighters and their equipments face. Lastly, thermal packaging methods that we have developed and tested are introduced.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.288-294
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• 2013

Chest digital tomosynthesis was the most advanced digital radiography technology, but it was higher patient dose than conventional chest radiography. Thus we tried to reduce a patient dose of chest digital tomosynthesis and evaluated its image quality. Result shows that radiation dose such as ESD, DAP and ED were 1.95 mGy, 17.66 $dGycm^2$ and 0.133 mSv respectively in default setting and 0.312 mGy, 2.27 $dGy.cm^2$ and 0.052 mSv in use additional filter, respectively. Doses were decrease 66.2%, 73.6% and 57.4% in ESD, DAP and ED, respectively. At the image quality assessment, overall sensitivities of use additional filter for nodule detection were not inferior to default mode for peripheral, central and peripheral micro nodules. However, sensitivity of low dose mode was significantly inferior to the default for central micro-nodules(p < .001).

• Journal of Biomedical Engineering Research
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• v.35 no.5
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• pp.151-159
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• 2014

Computed tomography (CT) is one of the most widely used medical imaging modality. However, substantial x-ray dose exposed to the human subject during the CT scan is a great concern. Region-of-interest (ROI) CT is considered to be a possible solution for its potential to reduce the x-ray dose to the human subject. In most of ROI-CT scans, the ROI is set to a circular shape whose diameter is often considerably smaller than the full field-of-view (FOV). However, an arbitrarily shaped ROI is very desirable to reduce the x-ray dose more than the circularly shaped ROI can do. We propose a new method to make a non-circular convex-shaped ROI along with the image reconstruction method. To make a ROI with an arbitrary convex shape, dynamic collimations are necessary to minimize the x-ray dose at each angle of view. In addition to the dynamic collimation, we get the ROI projection data with slightly lower sampling rate in the view direction to further reduce the x-ray dose. We reconstruct images from the ROI projection data in the compressed sensing (CS) framework assisted by the exterior projection data acquired from the pilot scan to set the ROI. To validate the proposed method, we used the experimental micro-CT projection data after truncating them to simulate the dynamic collimation. The reconstructed ROI images showed little errors as compared to the images reconstructed from the full-FOV scan data as well as little artifacts inside the ROI. We expect the proposed method can significantly reduce the x-ray dose in CT scans if the dynamic collimation is realized in real CT machines.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.128-131
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• 2007

da $Vinci^{TM}$ Surgical System is an advanced mode of minimal invasive surgery, using 3-dimensional imaging system and robotic arms which can mimic the dexterity of the human hand. Thus, various operations can be performed with minimal incision and limited surgical field and the merits of minimal invasive surgery can be maximized by using it. We report our first experience of robotic open heart surgery using the da $Vinci^{TM}$ Surgical System for repairing atrial septal defect.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.210-214
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• 2006

Objective : We investigate risk factors of cerebral microbleeds[MBs] and their relation to concomitant magnetic resonance[MR] findings in intracerebral hemorrhages[ICHs] patients. Methods : We studied 100 consecutive patients with primary ICH over a 1-year period. These patients underwent brain MR images using 3.0-T scanners within the first week of the hemorrhage. MBs and old hematomas were located and counted by using $T2^*-weighted$ gradient-echo MR imaging. We also counted lacunes and graded white matter and periventricular hyperintensity on T1- and T2-weighted spin-echo sequences. The association between MBs and vascular risk factors and MR abnormalities were analyzed. Results : MBs were seen in 77 of ICH patients, and their number ranged from 1 to 65 lesions [mean 11, median 6]. The locations of MBs were subcortex-cortex [40.6%], basal ganglia [26.7%], thalamus [14.1 %], brain stem [12.5%], and cerebellum [9.1 %]. Analysis of clinical data revealed that age, hypertension, history of stroke, and duration of hypertension were frequently associated with MBs. The incidence of lacunes, old hematomas, and advanced leukoaraiosis was significantly higher in the MBs group, compared with the patients without MBs. Conclusion : MBs are frequently observed in ICH patients with advancing age, chronic hypertension, and previous hemorrhagic stroke, and are also closely related with morphological signs of occlusive type microangiopathy, such as lacunar infarct and severe leukoaraiosis.

• Korean Journal of Metals and Materials
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• v.50 no.5
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• pp.401-406
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• 2012

When viewed using a magnetic resonance imaging (MRI) system, invasive materials inside the human body, in many cases, severely distort the MR image of human tissues. The degree of the MR image distortion increases in proportion not only to the difference in the susceptibility between the invasive material and the human tissue, but also to the intensity of the magnetic field induced by the MRI system. In this study, by blending paramagnetic Ti particles with diamagnetic graphite, we synthesized $Ti_{100-x}C_x$ composites that can reduce the artifact in the MR image under the high-strength magnetic field. Of the developed composites, $Ti_{70}C_{30}$ showed the magnetic susceptibility of ${\chi}=67.6{\times}10^{-6}$, which corresponds to 30% of those of commercially available Ti alloys, the lowest reported in the literature. The level of the MR image distortion in the vicinity of the $Ti_{70}C_{30}$ composite insert was nearly negligible even under the high magnetic field of 4.7 T. In this paper, we reported on a methodology of designing new structural materials for bio-applications, their synthesis, experimental confirmation and measurement of MR images.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.364-364
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• 2019

최근 전세계적으로 기후변화로 인한 국내외 가뭄에 대한 피해 및 발생 빈도가 점차 증가하고 있으며, 우리나라의 경우 2000년대 이후 가뭄 주기가 점점 짧아져 2013년 이후 매년 가뭄이 발생하고 있다. 북한은 자연재해에 취약한 국가이며 특히 가뭄으로 인한 식량난 문제가 대두되고 있지만, 북한의 제한적인 정보로 인해 북한 지역에서의 가뭄의 발생과 피해 정보는 한정적이고, 활용할 수 있는 자료의 경우 외국 기관의 정보에 의존하는 실정이다. 향후 농업부문에 대한 대북한 지원과 통일 후를 대비한 농업정책의 수립을 위하여 북한의 가뭄에 대하여 독자적으로 신속한 정보를 취득, 분석할 수 있는 능력을 확보하는 것이 필요하다. 위성영상을 이용한 원격탐사 기술은 접근이 용이하지 못한 지역의 주기적인 관측이 가능하며, 동일한 정확도로 기상자료의 획득이 가능하다. Vegetation Drought Response Index (VegDRI)는 위성영상기반의 가뭄지수인 정규식생지수(Nomalized Difference Vegetation Index, NDVI), 기상학적 가뭄지수를 활용한 기후적 요소, 토지피복 및 생태지역 등의 생물물리학적 요소를 활용한 가뭄지표이다. 본 연구에서는 MODerate resolution Imaging Spectroradiometer (MODIS) 위성의 MOD13Q1 영상자료의 NDVI (2001~2018년)를 이용하였으며, 북한의 기상자료를 이용한 표준강수지수 (Standardized Precipitation Index, SPI)와 파머가뭄심도지수 (Palmer Drought Severity Index, PDSI), 그리고 북한 지역의 토지피복 및 생태지역 등의 요소들을 활용한 VegDRI를 통하여 북한의 가뭄 시기에 따른 시도별 가뭄 특성에 대하여 분석하고자 한다.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2364-2370
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• 2021

The ⁿMCP (Neutron sensitive microchannel plate) combined with advanced readout electronics is widely used in energy selective neutron imaging because of its good spatial and timing resolution. Neutron detection efficiency is a crucial parameter for the ⁿMCP. In this paper, a mathematical model based on the oblique cylindrical channel and elliptical pore was established to calculate the neutron absorption probability, the escape probability of charged particles and overall detection efficiency of ⁿMCP and analyze the effects of neutron incident position, pore diameter, wall thickness and bias angle. It was shown that when the doping concentration of the ⁿMCP was 10 mol%, the thickness of ⁿMCP was 0.6 mm, the detection efficiency could reach maximum value, about 24% for thermal neutrons if the pore diameter was 6 ㎛, the wall thickness was 2 ㎛ and the bias angle was 3 or 6°. The calculated results are of great significance for evaluating the detection efficiency of the ⁿMCP. In a subsequent companion paper, the mathematical model would be extended to the case of the spatial resolution and detection efficiency optimization of the coating ⁿMCP.