• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.556-558
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• 2002

본 논문에서는 멀티미디어 게임의 흡인요소를 분석하였다. 인지 및 감성을 고려한 흡인요소에는 22가지가 있었다. 이 흡인요소들을 몰입차원과 구현방식 그리고 자극방법 등의 각도에서 그 상관관계를 파악하였다. 그 결과 게임의 흡인요소 22가지 중에서 새로운 게임을 설계할 때 일체감. 자극성, 도박, 현장감, 환상감, 만족감, 성취감 등의 7가지 요소를 우선적으로 고려해야 함을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.696-701
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• 2005

조화가진력이 작용하는 고정경계를 가진 완전원판의 비선형 진동에 대한 응답특성을 연구하였다. 원판의 비대칭모드의 고유진동수 근처에 가진주파수가 작용하는 주공진에서의 응답은 정상파(standing wave)뿐만 아니라 진행파(traveling wave)가 존재 한다고 알려져 있다. 주공진 근처의 정상상태 응답곡선에서 최대한 5개의 안정한 응답이 존재하는 것으로 밝혀졌으며, 이들은 1개의 정상파와 4개의 진행파로 나타난다. 이 진행파 중 2개는 가진진동수가 변화함에 따라 Hope분기에 의해 안정성을 잃은 후 주기배가운동을 거쳐 흔돈운동에 이르게 된다. 초기조건에 의해 각각의 끌개(attractor)에 흡인되는 흡인영역의 경계를 주평면의 개념을 통하여 구하였으며, 가진진동수가 변화함에 따라 안정한 해가 혼돈운동에 이르는 과정에 대해 흡인영역의 경계가 변화되는 특성을 관찰하였으며, 흡인영역 경계에 대한 프랙털 차원(fractal dimension)을 계산하였다.

• Korean Journal of Cognitive Science
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• v.15 no.3
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• pp.45-55
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• 2004

Immersion means the state of total devotion to what one is involved in. The typical form of this immersion experience happens when one is engaging in computer games. We analyze how the users became immersed in computer games. There are 22 elements of immersion involved in cognitive and emotional fun based cm the flow theory. After analyzing these elements with respect to flow dimension and game mechanics, we find that there are differences in the degree of their immersion in games. There are 7 elements that may be considered preferentially in designing computer games: unity, stimulation, gambling, virtual reality, fantasy, satisfaction accomplishment. We match these elements to Roget's categories and search for new categories with heading information and reference information. As a result 22 immersion elements are subdivided into 229 factors in the concrete. With these factors, we can design a multimedia game which has mon powerful immersion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.304-307
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• 1995

In this paper, an optical sensing system has been developed to detect the dust in vacuum cleaner. The system works well through self-tuning mechanism, even though there are systemic variance and characteristic change which is caused by the pollution on the surface of the optical elements. Using the developed sensing system, a novel suction power control system has been proposed, which is able to be used for a long time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1055-1056
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.745-746
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• 2010

• Journal of Power System Engineering
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• v.16 no.3
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• pp.64-68
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• 2012

Because the magnetic bearing supports levitating body without contact, wear, noise and vibration are very small comparing with mechanical bearings, it is very useful to high revolution machinery. In general, the magnetic attractive force function that is proportional to square of control current(x), and inversely proportional to square of an air gap(i) has been widely used. This paper proposed the new magnetic attractive force function that is proportional to cube of the control current, and inversely proportional to square of the air gap. The function was optimized to minimize the cost function that is the percentage of deviation about the change of a proportional constant(k), using the experimental data, ie, control currents and air gaps.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.523-535
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• 2008

A simulated rainfall system was built, and the unsaturated characteristics were examined by execution of simulated rainfall system test and soil water characteristic curve cell test(SWCC Cell Test) under the various rainfall and slope conditions. With the results, the applicability of infiltration behavior under rainfall and soil water characteristic curve models to the unsaturated weathered granite soil was examined. At the results of comparison the volumetric water content and matric suction measured in the wetting process(under rainfall) with those in the drying process(leaving as it was) of the simulated rainfall system, the volumetric water content showed a difference of $2{\sim}5%$ and matric suction of about $3{\sim}10\;kPa$, indicating the occurrence of hysteresis. In addition, the difference was relatively larger in matric suction than in the volumetric water content, and this tells that the hysteresis behavior is larger in matric suction. When the soil water characteristic curve derived from measurements in simulated rainfall system test were compared with those from the soil water characteristic curve cell test, both methods produced soil water characteristic curves close each other in the wetting process and the drying process, but in both, there was a difference between results obtained from in the wetting process and those from in the drying process. Thus, when soil water characteristic curves are rationally applied to the design and stability analysis considering of the properties of unsaturated soil, it is considered desirable to apply the soil water characteristic curve of the wetting process to the wetting process, and that of the drying process to the drying process.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.15-21
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• 2003

A series of triaxial compression tests were performed on samples of compacted granite soil in a modified triaxial cell that allowed separate control of pore air pressure ($U_a$) and pore water pressure ($U_w$) in order to examine the characteristics of pore pressure, volume change and stress-strain behavior during undrained loading conditions. Triaxial samples of unsaturated and saturated compacted granite soil, 50mm in diameter and 100mm in height, were prepared by compaction in a mould. These samples were tested at 3 different suction values (0.5, 1.0, 2.0 kgf/cm$^2$) for unsaturated compacted granite soil and at 3 different confining stresses (1.0, 2.0, 4.0 kgf/cm$^2$). Results showed that only effective cohesion increased with little variation of friction angle, according to matric suction.

• Tuberculosis and Respiratory Diseases
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• v.64 no.5
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• pp.356-361
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• 2008

Background: We wanted to examine the clinical characteristics of adult patients with tracheobronchial foreign bodies (FBs) according to the risk of aspiration and the outcomes of intervention with using a fiberoptic bronchoscope. Methods: From December 1994 through December 2004 at Kyung Hee Medical Center, we retrospectively analyzed the medical records of 29 adult patients with FBs that were identified by using a fiberoptic bronchoscope. Results: 14 patients were not at risk of aspiration, whereas 15 had cerebrovascular diseases and they were at a high risk of aspiration. No history suggestive of FB aspiration was noted in 7 (24.1%) patients. Respiratory symptom(s) were noted in 22 patients, and these symptoms were cough (62.0%), dyspnea (44.8%), fever (20.7%), wheezing (13.8%), chest pain (10.3%) and hemoptysis (0.4%). Only 60% of those patients at a high risk of aspiration had symptom(s) (92.8% of those patients without a risk of aspiration had symptoms, p=0.005). Those patients at risk for aspiration had a longer duration of symptoms (median: 4 days vs. 2 days for those patients not at risk for aspiration, p=0.007) before diagnosis. Acute respiratory symptom(s) within 3 days after aspiration were more frequent in the patients without a risk of aspiration (9 vs. 4, respectively p=0.048). Chest x-ray revealed radiological abnormalities in 23 patients, and these were opacities suspicious of FB (n=11), pneumonia (n=8), air trapping (n=5) and atelectasis (n=3). There were no differences in radiological findings according to the risk of aspiration. FB aspiration developed most commonly during medical procedures (57.1% for the patients at risk) and during eating (35.7% for the patients without risk). The most common FB materials were teeth (n = 11). Alligator jaw biopsy forceps (n = 23) was the most commonly used equipment. All of the FBs were removed without significant complications. Conclusion: This study underlines that a tracheobronchial FB in the patients who are at a high risk of aspiration are more likely to overlooked because of the more gradual onset of symptoms and the symptoms develop iatrogenically in many cases.