• Journal of radiological science and technology
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• v.37 no.2
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• pp.93-100
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• 2014

Recently the development of portable digital wireless imaging system, which acquires digital radiation images by using wireless LAN telecommunications function in an easy and fast way, provides lots of convenience for people. Considering the characteristics of portable imaging tests on emergency and critical patients, this study aims to suggest guidelines for Digital wireless detector by evaluating the effect of de-centering of focus-grid and displacement of subject in detector on the quality of image. The equipments used for this study were Elmo-T6 Digital Mobile X-ray system (SIMAZU Corp.), el' Tor ($14{\times}17$ "Wireless detector), Grid (10:1) and Chest & head phantom. After acquiring post-processing image according to dose increase and de-centering image of grid-focus and head phantom displacement image, this study compared, analyzed and evaluated these images by using a digital image analysis program by Image J. In the change of images based on dose increase, images were rough in the dose of 0.5 mAs, while there was no difference among images in the proper dose of 1~2 mAs and, especially from 2.5 mAs, average value of pixels radically decreased, affecting contrast. Over 3 mAs, contrast dropped due to saturation phenomenon of lungs. As the result of analysis using Image J program, with the increase of displacement between focus-grid and head phantom, the frequency of low pixel value also increase, causing the outline of surface image to disappear, which in turn affects contrast. For better quality imaging, a radiographer must be aware before the time of test that the image quality can be changed based on the critical patient's posture, movement, respiration, displacement of X-ray tube and distance of imaging.

• Journal of the Mineralogical Society of Korea
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• v.4 no.1
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• pp.43-50
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• 1991

Two solid solution-type phases has been experimentally found in the quaternary system Cu-Fe-Sn-S:$(Fe, Cu, Sn)_{1+x}$ and $Cu_{2-x}Fe_(1+x}SnS_4$. These solid solutions are stable around the CuS-FeS-SnS referecne plane in the composition tetrahedron. One is the sphalerite-type monosulfide solid solution which has a extensive stability range with varying degrees of sulfur/metal ratio 9.7-1.0/1.0. The other is tetrahedrite-type phase $Cu_{2-y)Fe_{1+y}SnS_4(y_{max}=0.4)$ which is stable along the $Cu_2FeSnS_4-FeS$ tie line, but shows no phase transformation in the subsolidus range and decomposes incongruently at the range of 835-862${\circ}C$, depending on the compositional variation. Particularly, the latter phase shows the characteristic superstructure reflections, indicating that it is a derivative of sphalerite structure. The stability field of these two sphalerite-type phases are defined on the basis of diffraction pattern and optical homogeneity of the synthetic materials at the temperature range of 700-400${\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.240-245
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• 2011

This research focused on the intercalation behavior of recrystallized ibuprofen into clay as a sustained release drug carrier. The intercalation behaviors of ibuprofen were determined by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The basal spacing ($d_{001}$) of clay increased from 1.2 nm to 1.5 nm by ibuprofen molecules. The segmental motion effect of ibuprofen into the clay interlayer spacing also increased the thermal stability of the ibuprofen/clay nanocomposites. The in vitro drug release results of nanocomposites showed that ibuprofen was released from clay steadily.

• Polymer(Korea)
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• v.27 no.2
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• pp.91-97
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• 2003

The effect of fluorination of nanoscaled silicas on mechanical interfacial properties and thermal stabilities of the silica/polyurethane composites was investigated. The surface properties of the silica were studied in X-ray photoelectron spectroscopy and contact angle measurements. Their mechanical interfacial properties and thermal stabilities of the composites were characterized by tearing energy and decomposition activation energy, respectively. As experimental results, the London dispersive component of surface free energy and fluorine functional groups of silica surfaces were increased as a function of fluorination temperature resulting in improving the trearing energy ($G_{IIIC}$) of the composites. Also, the thermal stabilities of the composites were increased as the treatment temperature increases. These results could be explained that the fluorine functional groups on silica surfaces played an important role in improving the intermolecular interactions at interfaces between silicas and polyurethane matrix in a composite system.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.537-558
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• 2005

This paper addresses the results of HAUSAT-2 radiation environment and effect analyses, including TID and SEE analyses. Trapped proton and electron, solar proton, galactic cosmic ray models were considered for HAUSAT-2 TID radiation environment analysis. TID was analyzed through total dose-depth curve and the radiation tolerance of TID for HAUSAT-2 components was verified by using DMBP method and sectoring analysis. HAUSAT-2 LET spectrum for heavy ion and proton were also analyzed for SEE investigation. SEE(SEU, SEL) analyses were accomplished for MPC860T2B microprocessor and K6X8008T2B memory. It was estimated that several SEUs may occur without SEL during the HAUSAT-2 mission life(2 years). Software Hamming Code EDAC has been implemented to detect and correct the SEU. In this study, all radiation analyses were conducted by using SPENVIS software.

• Journal of the Korean Electrochemical Society
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• v.17 no.4
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• pp.209-215
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• 2014

We report on the electrocatalytic activities at Pt nanostructure surfaces electrodeposited with different deposition charges on indium tin oxide electrodes for oxygen reduction and methanol oxidation reactions. The surface properties of Pt nanostructures depending on deposition charges were characterized by scanning electron microscopy, electrochemical surface area measurement, X-ray diffraction, and CO stripping analysis, which were correlated to the electrocatalytic activities. Pt nanostructures with deposition charge of 0.03 C exhibited the highest electrocatalytic activity for oxygen reduction and methanol oxidation. The sharp sites of Pt nanostructure and the presence of highly active facet play a key role, whereas the electrochemical surface area does not significantly affect the electrocatalytic activity. The results obtained in this work with regard to the dependence of electrocatalytic activity on the variation of the Pt nanostructures will give insights into the development of advanced electrocatalytic systems.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2002.06a
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• pp.89-104
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• 2002

유전체연구사업단은 국내에서 발병 및 사망빈도가 가장 높은 위암과 간암의 퇴치를 목적으로 국가적 특목전략사업으로 연구를 추진하고 있다. 이와 별도로 보건복지부에서는 22개의 중요 질병별 유전체 연구센터를 전국적으로 추진하고 있다. 따라서, 연구가 성공적으로 진행되면 각 연구소에서 독자적으로 개발하여 제공하는 생명정보의 양은 거의 무한에 이를 것이다. 그러나 생명정보는 환자진료에 도움을 주기 위해서는 궁극적으로 임상정보와 함께 유기적으로 통합되어야 한다. 임상정보와의 통합을 위해서는 의료기관의 진료정보와 연구소의 생명정보가 연계되어 엄밀한 임상실험이 추가적으로 실시되어야 한다. 뿐만 아니라 생명정보학의 발전을 위해서는 연구대상의 임상정보가 공유되어야 한다. 유전체정보를 이용하는 생명정보학(Bioinformatics)은 각 국가마다 전략사업으로 간주하여 막대한 투자가 이루어지는 새로운 분야이다. 현재 선진국에서 개발 사용 중인 시스템의 연간 사용료가 고가이므로 국내 도입은 거의 불가능하거나 또는 매우 비효율적이다. 유전체 또는 생명정보의 임상활용 및 생명정보연구를 위한 임상정보 공유를 위해서는 우선 다음의 사항이 개발되어야 한다. 1) 다음과 같은 개별환자의 정보를 각 의료기관에서 제공 받아 저장 활용한다. - 진찰 및 임상소견, 수술기록, 경과기록, 검사결과 (임상병리, 해부병리, 방사선 등), - 영상정보 (X-ray, CT, MRI, 초음파, 전자현미경, 그래픽 등), - 환자개인기록(병력, 과거력, 가족력, 알러지 등), - 예방접종 기록 2) 각 연구소에서 첨단기술을 이용하여 개발되는 생명정보를 임상에 활용하기 위해서는 유전체연구센타와 병원간에 임상정보와 유전체 분석정보의 공유가 필수적으로 발생하게 됨으로, 유전체 정보와 임상정보의 통합은 미래 의료환경에 필수기능이 될 것이다. 3) 각 생명공학 연구소에서 사용하는 첨단 분석 장비와 생명공학 정보시스템의 자동 연계가 필요하다. 현재 국내에는 전국적인 초고속정보망이 가동되어 웹을 기반으로 하는 생명정보의 공유는 기술적으로 문제가 될 수 없으나 임상정보의 유전체연구에 그리고 유전체연구정보의 임상활용은 다양한 문제를 내포하고 있다. 이에 영상을 포함한 환자정보의 유전체연구센터와 병원정보시스템과의 효율적인 연계통합 운영을 위해 국내에서는 초기 도입단계에 있는 국제적인 보건의료정보의 표준인 Health Level 7 (textural information 공유), DICOM (image 및 wave 공유), 관련 ISO표준, WHO의 ICD9/10 (질병분류), LOINC (검사 및 관련용어), SNOMED International (의학용어) 등을 활용하여야 한다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.60-67
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• 2017

A baggage handling system (BHS) in airport is an unified system for moving the passengers' baggage in designated time. Input baggage from the check-in counter travels to the baggage claim area or cargo handling terminal through this system. In particular, entryway BHS consists of conveyors, X-ray and sorters such as tilt-tray to send the baggage to departing airplane and it could have various problems for handling certain amount of baggage in restricted time such as baggage jamming at certain merge point. This causes systemic error such as delay of the time, omissions of the baggage and even breakdown of the equipment and inefficiency. Also the increasing maximum time of the baggage passing through the BHS could delay the flight schedule and finally decrease the service level. Thus, the algorithm for controlling the flow of the merge is essential to the system. The window reservation algorithm is the one of the most frequently used methods to control the merge configuration. Above all, the reserve location, so called reserve ahead point, that allocates the window is important for the performance of the algorithm. We propose the modified window reservation algorithm and the best reserve locations by changing the reserve ahead point in the induction conveyors. The effect of various reserve ahead points such as the capacity and utility of the system were analyzed and the most effective reserve ahead point combination was found. The total baggage processing time and the utilization of the tilt-tray are properly considered when choosing the optimal Reserve ahead point combination. In the layout of this study, the configuration of four conveyors merged into one tilt-tray is studied and simulation analysis is done by AutoMod(R), 3D simulation software. Through the simulation, the window reservation algorithm is effectively operated with the best combination of reserve ahead point which reduces the maximum baggage travel time.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.939-945
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• 2023

This study analyzes the 'performance efficiency' of AI-based reading assistance systems in the field of radiology by measuring their 'time behavior' properties. Due to the increase in medical images and the limited number of radiologists, the adoption of AI-based solutions is escalating, stimulating a multitude of studies in this area. Contrary to the majority of past research which centered on AI's diagnostic precision, this study underlines the significance of time behavior. Using 50 chest X-ray PA images, the system processed images in an average of 15.24 seconds, demonstrating high consistency and reliability, which is on par with leading global AI platforms, suggesting the potential for significant improvements in radiology workflow efficiency. We expect AI technology to play a large role in the field of radiology and help improve overall healthcare quality and efficiency.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.859-863
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• 2023

In this study, simple and portable radiation detection system using X-ray intensifying screen, optical sensor and micro-controller unit for education was proposed. The system was simply composed of detection unit consisting of an optical sensor and intensifying screen, micro-controller unit, and was designed to be suitable for portable. Radiation was measured using developed detection system and absorbed dose dosimeter with changing tube voltage from 50 to 100 kVp. The tube current and SDD were fixed on 100 mAs and 100 cm, and dose were measured repeated ten times at each tube voltage. The response and linearity of the detection system were confirmed using the measured values. It was confirmed that the comparison measurement results of the detection system and absorbed dose dosimeter showed a high correlation(r : 0.998, p<.001). In this results, the feasibility of the detection system with intensifying screen and micro-controller unit based was confirmed, and we considered that the developed detection system could be applied to portable, compact, low cost system for education.