• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.57-58
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• 2015

실시간성이란 연산의 정확성과 연산 수행시간이 예측 가능한 시간 내에 완료되는 것을 말한다. 범용 운영체제인 리눅스에서는 CFS(Complete Fair Scheduling)을 사용하여 높은 우선순위 태스크에 대한 빠른 응답성을 보장할 수 없기 때문에 실시간성을 제공하지 못한다. 이를 해결하기 위해 RTiK-Linux(Real-Time implanted Kernel for Linux)가 개발되어 리눅스 환경에서 실시간성을 제공하였지만 개발 당시 싱글프로세서 환경만을 고려하여 최근 사용되는 멀티프로세서 환경에서는 실시간성 제공에 어려움이 있다. 본 논문에서는 멀티프로세서 리눅스 상에서 발생하는 RTiK-Linux의 문제점에 대해 설명하고 이에 대한 해결방안을 기술하여 멀티프로세서 리눅스 상에서 실시간성을 제공하기 위한 방안을 연구하였다.

• The Journal of the Korean dental association
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• v.38 no.10 s.377
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• pp.942-955
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• 2000

지난 5월 25일의 미국의 보건복지부는 구강건강에 대한 의정백서를 발표했다. 이는 미국의 복지부장관인 샬라라(Donna E.Shalala)장관의 지시에 따라 의정국장인 스케처(David Scatcher)박사가 발표한 것으로서 미국 역사상 처음으로 구강건강에 대한 의정백서를 완료한 것이다. 샬라라 장관은 "처음으로 이러한 보고서를 작성한 목적은 국민들에게 구강건강의 진정한 의미를 확실히 인식하게 하고 구강건강이 전신의 건강과 복지에 얼마나 중요한 역할을 하고 있는지에 대해 주지시키기 위함"이라고 밝혔다. 보고서에서는 구강건강이 건강한 치아만을 말하는 것이 아니라는 사실을 상기시키고 구강건강없이 전체적으로 건강하다고 말할 수 없다고 지적하고 있다. 또한 보고서에서는 모든 사람이 구강건강을 향상시키고 구강 질환을 예방하는 과정에 활용할 수 있는 안전하고 효과가 확실한 질병예방법에 대해 요약했다. 미국의 구강백서는 모두 305쪽에 달하는데 이중 실무요약한 25쪽을 한글로 번역해 2회에 걸쳐 게재한다.

• The Korean Journal of Zoology
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• v.35 no.1
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• pp.58-69
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• 1992

곤충 혈구의 이물질에 대해 면릉고청을 확인하기 위하여 평균지름 10 nm의 gold입자를 함유한 colloidal gold solution을 등 검은 메뚜기 (Euprepocnemis shirakii Bolivar) 성충의 복강에 주입한 후, 혈구의 반응양상을 전자현미경으로 관찰하였다. Gold 입자에 대한 혈구의 면역반응은 전체 혈구의 약 28%를 차지하고 있는 Plasmatocytes에서 식세포작용(phagocytosis)의 형태로 확인되었고, 다른 종류의 혈구는 반응하지 않았다. Plasmatocytes에 의해 식세포작용의 초기반음은 많은 원형질 돌기를 형성하여 이물질을 포획하는 태면반응과 원형질악의 함입에 의한 식포의 형성과정으로서, 이 과정은 이물질 주입후 10분이내에 완료되는 것으로 관찰되었다. 혈구내에 형성된 식포는 초기에 전자밀도가 낮은, 천상 또는 섬잡상의 내부구조를 가지고 있었으나, 일차 Iysosome의 융합에 의해 전자밀도가 높은 과립상으로 된 후, 결정상의 내부구조로 변형되었으며, 그 이후의 단계에서 multivesicular body형태의 이차 Iysosome을 형성하였다.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1235-1240
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• 2003

The mixtures which are in the chemical composition of Portland cement were prepared from oyster shell, casting dust and BOF slag. The clinkerbility and the behaviour of formation of clinker minora]s were studied using the mixtures mainly by the mineral and microstructural observation. By virtue of the characteristics of starting raw materials, the clinkering temperature was lower as much as 100$^{\circ}C$ than that of a mixture prepared from normal raw materials. Uncombined calcium oxide was vanished entirely below 1350$^{\circ}C$. and the formation of major cement minerals such as alite and belite could be nearly accomplished without too much liquid phase within 1400$^{\circ}C$.

• Resources Recycling
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• v.18 no.6
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• pp.3-9
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• 2009

The present review paper deals the liquid-liquid extraction (LLE) general principles and the basic fundamentals, general process of LLE followed by the importance of LLE reagents. LLE is a process of transferring a chemical compound from one liquid phase to a second liquid phase, immiscible with the first. In analytical chemistry, this method enjoys a favored position among separation techniques because of its simplicity, speed and wide scope. By utilizing apparatus no more complicated than a separatory funnel and requiring several minutes at most to perform, extraction procedures offer much to the analytical chemist.

• Journal of Conservation Science
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• v.29 no.4
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• pp.297-309
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• 2013

Iron objects become corroded at fast speed from the moment when they are excavated, so it is needed to control corrosion through processes of conservation treatment. However, re-corrosion mostly takes place in excavate iron objects, although they have already gone through the process of conservation treatment, and it is more difficult to carry out the second conservation treatment of re-corroded excavated iron objects than the first conservation treatment, and it requires a longer period of time to treat them as well. In this study, aims to discover factors of re-corrosion by scientifically analyzing corrosion products generated during the process of storage after the process of conservation treatment. The finished on conservation treatment of the iron artifacts, which were unearthed from three ancient site in Gyeongju by using the same conservation method between 2002 and 2009, re-corrosion condition observed on the packaging-iron artifacts. Focused on 9 target forged iron artifacts among them, this study analyzed the physical changes by mass measurement, naked-eye and microscopic observations and the chemical changes by SEM-EDS, XRD, IC and ICP analysis. The results show that the yellowish brown corrosion products formed on the facing surface of part dropped from the artifacts had different associated forms but acicular shape. In addition, the acicular shape became clearer as the color changed from red to yellowish brown. According to the process when the conservation treatment was completed, the mass of the artifacts increased in proportion to the corrosion products and the chloride ion ($Cl^-$) concentration had a tendency to increase relatively. ${\beta}$-FeOOH (akaganeite) was confirmed in the XRD analysis for the corrosion products of all the collected samples. As a result of ICP analysis, $Na^+$ and $Ca^{2+}$ components were confirmed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.629-635
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• 2012

This paper presents a performance analysis of the GPS(Global Positioning System) receiver on board in LEO satellites, based on the comparison of its in-orbit performances and corresponding ground test results. An extensive ground tests on the subject GPS receiver has been performed in diverse conditions under the right frame of ground test environments and the analysis of in-orbit performances has also been performed with the huge amount of accumulated GPS data which has been in operation for 6 years since its launch on 2006. For this analysis, we chose three sets of in-orbit data; the data during the early mission period, the data at the 3-year mission completion time, and the most recent in-orbit data. As the performance measures, we selected the position and time synchronization accuracy, and the comparative analysis shows the concurrency between the in-orbit performances and the ground test results with in these performance measures, verifying the validity of the ground test. It is expected that the test configuration and analysis method presented in this paper can be applied to developing and verifying the future Koreanized satellite GPS receivers.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.601-606
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• 2009

Amelogenesis Imperfecta (AI) is a genetic disorder which retards the development of enamel and it can be classified into three types: hypoplastic, hypomaturation, hypocalcified type. This can occur both in deciduous and permanent dentition. A 8 year 8 month old patient with a chief complaints of delayed eruption on upper anteriors, calculus deposit on lower anteriors and anterior openbite visited the clinic. Anteriors had thin layer of enamel and were very narrow. Especially lower anteriors had rough surface and were in bad shape. Teeth were very hypersensitive to thermal changes. Upper and lower first molars showed severe attrition on the occlusal surface. Radiographs also verified hypoplastic enamel in the whole dentition including the teeth in the tooth bud. The patient was diagnosed as hypoplastic AI, and is being treated at the pediathc and prosthodontic department of the Kyunghee dental university hospital. To improve the function, esthetics, hypersensitivity of the AI patients, restorations on the posteriors and the anteriors with oral hygiene instruction are necessary, Constant follow-up check is needed until full growth and after full growth, cooperative care with the other department is needed.

• Science of Emotion and Sensibility
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• v.26 no.1
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• pp.65-78
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• 2023

Aircraft are representative of human-machine systems. There is a delay between the human operation and the completion of the machine operation such as when the machine starts to operate and when the force is transmitted to the machine and completed. Time perception is an important component of timing tasks and is known to be affected by the anxiety associated with high arousal. This research verified the impact of weather, flight, and time conditions on the anxiety and time perception of in-service pilots in a virtual reality area. Weather conditions were divided into visual flight weather conditions and very low visibility conditions. Experiments 1 and 2 were performed with different flight and time conditions. In Experiment 1, time perception was measured by employing a button added to the control rod in the scenario of hovering and level flight with relatively little transformed in momentum and little delay. In Experiment 2, time perception was measured in the procedure of naturally taking off the helicopter by employing only the control stick in a takeoff scenario where there was a lot of transformation in momentum and a lot of delays. As a result of the experiment, it was reported that anxiety and heart rate increased in very low visibility conditions In particular, among all flight conditions in Experiments 1 and 2, it was reported that time was overestimated in the scenario of increased anxiety. This outcome can lead to overestimation of time under the impact of anxiety and failure of the timing task, which may lead to challenges in maneuvering and possibly lead to accidents.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.17-29
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• 2012

To investigate the characteristics of shear strength and soil deformation in soft grounds, in which various vertical drains were placed, two hundreds field monitoring data of embankments performed in thirteen road construction sites at west and south coastal areas of the Korean Peninsula were collected. At first, the relationship between settlement and lateral displacement was investigated into three stages, in which embankment construction works were divided into initial filling stage, final filling stage and stage after complete filling. And then, the relationship of surcharge pressures and embankment heights with undrained shear strength of soft grounds were investigated. The investigation on settlement and lateral displacement illustrated that the increment of lateral flow to the increment of settlement was low during initial filling stage, but increased gradually with filling and showed largest during final filling stage. After complete filling, the lateral displacement was converged, even though the settlement was increased continuously. Therefore, most of lateral flow was occurred during embankment filling. The ratio of the lateral displacement increment to the settlement increment was 20% for initial filling stage, which coincided with the one presented by Tavenas et al.(1979), but became 50% for final filling stage, which was half of the one presented by Tavenas et al.(1979). However, the ratio reduced to 1% to 9%, which was quite lower than the one presented by Tavenas et al.(1979). Shear deformations, even shear failures, were predicted in soft grounds under initial undrained shear strength, since the design heights of embankments were higher than the yield height in all the sites. However, embankment construction would be possible since the yield height became higher than the design height due to improvement of shear strength of soft grounds with application of the vertical drains. In order to perform safely embankments for road constructions, the embankment loads should be designed not to be exceed 5.14 times the initial undrained shear strength of soft grounds and to be less than 3.0 times the undrained shear strength improved with application of vertical drains in soft grounds.