• Journal of Korean Neurosurgical Society
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• v.41 no.3
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• pp.186-189
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• 2007

Metastasizing mixed tumors [MMT] of salivary glands are inexplicably metastasize maintaining benign histology. There is no pathologic and flow cytometric analysis criteria to predict the metastasis. MMT is known to metastasize by local implantation, vascular and lymphatic embolization after multiple surgery to local recurrences of primary tumor. However, multiple metastasis including cranium and spine occurred even without surgery to the primary tumor in this case. No pathological evidence of malignancy could be found in both primary and metastatic tumor. MMT is considered as an low grade malignancy based on clinical behavior rather than histologic evidence, such as low mortality rate, long delay of metastasis after primary lesion. Cranial metastasis is also extremely rare and only two cases have been reported. We report this unusual case with a literature review.

• Annual Conference of KIPS
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• 2017.11a
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• pp.126-127
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• 2017

사물인터넷 산업이 발전함으로써 차량 간의 통신이 주목 받고 있다. 네트워크 연결이 빈번하게 끊어지는 자동차 사이에서 무선으로 통신을 하기 위한 네트워킹에 대해 알아본다. 이를 위하여 차량이 노드 역할을 하는 VANET 환경에서 CCN을 적용하여 Data Packet 수를 살펴보았다.

• Annual Conference of KIPS
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• 2017.04a
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• pp.605-608
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• 2017

최근에는 의료기기의 구성 요소 중 소프트웨어의 기능과 역할이 커지면서 의료기기 소프트웨어의 비중이 높아지고, 의료기기의 사용자의 생명과 안전에 직결되는 특성으로 인해 의료기기 소프트웨어 위험관리의 중요성은 더욱 강조되고 있다. 이를 위해 여러 표준들은 위험관리를 위한 다양한 요구사항들을 제시한다. 그러나 의료기기 소프트웨어 개발생명주기의 각 단계에서 수행되어야하는 위험관리 항목들은 분류되어있지 않다. 이로 인해 개발자들은 의료기기 개발 중에 직접 표준들의 연관성을 분석하여 위험관리 활동을 수행해야하는 어려움을 겪고 있다. 따라서 본 논문에서는 위험관리 프로세스의 항목들을 추출하고 PEMS(Programmable Electrical Medical System) 개발생명주기와 대응시켜 연관성을 분석하고, 이를 통해 의료기기 소프트웨어의 개발 중 효과적이고 체계적인 위험관리를 가능하게 한다.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.43-48
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• 2008

This paper proposes a new method for measuring the power of spherical and cylindrical lens with 6 points light source, which is composed of a LED and six holes, and magnification ellipse fitting algorithm. Each measured diagonal length of 6 points light source is determined by the target lens power. After finding the center position of each light point with threshold method, 3 axis-diagonal lengths were calculated. The long axis and short axis power of cylindrical lens can be calculated by using magnification ellipse fitting algorithm with the magnification relationships between the initial diagonal lengths and the measured diagonal lengths changed by lens power.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.594-597
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• 2007

The notebook system use the radial fan to cool the main chipsets which generate heat. It needs to improve cooling performance by increasing fan RPM or increasing fan volume. But the former accompanies acoustic noise problem and the latter has a limitation due to notebook height and cooling area. So this study shows fatal parameters in the fan performance view point, and optimization process with Design Of Experiment. With this result, the fan CFM increases with same size of fan and we can use it as a result of decreasing fan acoustic noise.

• Journal of Trauma and Injury
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• v.30 no.2
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• pp.59-62
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• 2017

Lupus thrombocytopenia is a common clinical manifestation in systemic lupus erythematosus (SLE). It may present to clinicians with considerable therapeutic difficulties. We experienced a 40-year-old poly trauma patient with lupus thrombocytopenia who had been treated with immunosuppressive drugs for SLE. She was treated for refractory thrombocytopenia with platelet transfusion, corticosteroid and Intravenous immunoglobulin (IVIG). Fourteen days after admission, her platelet count started to increase, $101{\times}103/ul$ at 16 days after admission. Trauma patients may carry various underlying diseases and thus trauma surgeons should always be aware and ready for peculiar situations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.11
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• pp.1595-1603
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• 2003

Droplet combustion at high ambient pressures is studied numerically by formulating one dimensional combustion model in the mixture of n-heptane fuel and air. The ambient pressure is supercritical conditions. The modified Soave-Redlich-Kwong state equation is used in the evaluation of thermophysical properties to account for the real gas effect on fluid p-v-T properties in high pressure conditions. Non-ideal thermodynamic and transport property at near critical and supercritical conditions are also considered. Several parametric studies are performed by changing ambient pressure and initial droplet diameter. Droplet lifetime decreased with increasing pressure. Surface temperature increased with increasing pressure. Ignition time increased with increasing initial droplet diameter. Temporal or spatial distribution of mass fraction, mass diffusivity, Lewis number, thermal conductivity, and specific heat were presented.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.225-236
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• 2004

Diesel engines which emit a lot of PM and NOx have been known as a main air polluter. Especially, diesel particulate matters (OPM) including black smoke are hazardous air pollutants to human health and environment. The nations retaining advanced engine technologies have reinforced emission regulations. To meet these regulations diesel engine manufacturers have developed low-emission diesel engines, aftertreatment equipments, alternative fuel technologies and so on. In this study, particle number concentrations characteristics according to particle size and engine driving conditions were analyzed when these low-emission technologies were applied. There was a tendency of increasing particle number concentrations from heavy-duty diesel engines with increasing engine rpm and load rate. In the cases of COPF (Catalytic Diesel Particulate Filter), CNG (Compressed Natural Gas) engine and ULSD (Ultra Low Sulfur Diesel) more than 99% of particle number concentration were removed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.1-8
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• 2007

Spray characteristics of a unlike triplet injector were investigated experimentally. Spray images and SMD of droplet were measured to evaluate the spray characteristics injected by liquid/gas combinations. G-L-G(Gas-Liquid-Gas), L-G-L(Liquid-Gas-Liquid) type of injector were used by changing the gas and liquid feed lines. The SMD graph shows that the droplet sizes decrease in the out of radial direction at a fixed gas Reynolds number. The SMD value of decreasing tendency shows that the more ethyl alcohol ratio increase, the more SMD value decrease.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.1
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• pp.1-10
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• 2007

When detonation is occurred, the working fluid is compressed itself, though there are no other devices that compress the fluid. As a result, an engine which uses detonation for a combustion process doesn't need moving parts so that the engine can be lighter than other engines ever exist, and such an engine is often referred to as a pulse detonation engine. Since using detonation has higher performance than using deflagration, many studies have been attempting to control and analyze the engines using detonation as combustion. The purpose of this study is to analyze the hybrid cycle which is consisted of Brayton and Pulse Detonation Engine cycle. At first, we set the theoretical basis of detonation analysis, and after that we consider two hybrid cycles; a turbojet hybrid cycle and a turbofan hybrid cycle. The more energy released, the higher detonation Mach number the detonation wave has. In general, a cycle which has a detonation process has higher performances but thermal efficiency of hybrid turbofan engine.