• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.7
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• pp.711-717
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• 2008

A modeling method for the modal and the transient vibration analysis of a multi-packet blade system excited by nozzle jet forces is presented in this paper. Blades are idealized as cantilever beams and the elastic structures like disc and shroud connecting blades are modeled as coupling stiffnesses. A modified Campbell diagram is proposed to identify true resonance frequencies of the multi-packet blade system. Different from the SAFE diagram that employs three dimensional space, the modified Campbell diagram Proposed in this study employs a plane to find the true resonance frequencies. To verify the existence of true resonance frequencies, nozzle jet forces are modeled as periodic forces and transient vibration analysis were performed with the modeling method.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.44-44
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• 2003

To determine feasibility of contrast-enhanced MRI (co-MRI) at true end-diastole (ED) free from limitation of time for inversion-recovery and trigger window for quantifying transmural extent of infarction. 대상 및 방법： MRI was performed in 18 patients with myocardial infarction. Cine imaging and co-MRI with same registered slices in short axis were peformed. To allow true ED co-MRI, ECG synchronization should use two RR-intervals for one acquisition of a segment of k-space by setting the heart rate to half that of the true heart rate. Trigger delay time was adjusted to the RR-interval for imaging at ED and to the sum of RR-interval plus the time between R-wave and the end-systole (ES) determined in cine images for imaging at ES.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.91-91
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• 2003

To determine feasibility of contrast-enhanced MRI (co-MRI) at true end-diastole (ED) free from limitation of time for inversion-recovery and trigger window for quantifying transmural extent of infarction. 대상 및 방법： MRI was peformed in 18 patients with myocardial infarction. Cine imaging and co-MRI with same registered slices in short axis were performed. To allow true ED co-MRI, ECG synchronization should use two RR-intervals for one acquisition of a segment of k-space by setting the heart rate to half that of the true heart rate. Trigger delay time was adjusted to the RR-interval for imaging at ED and to the sum of RR-interval plus the time between R-wave and the end-systole (ES) determined in cine images for imaging at ES.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.421-423
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• 2002

Senile involution is divided into two classes : physiological senile involution and pathological senile involution. Physiological senile involution is a natural process of vital action of decreasing Vital Essence and Energy in kidney that is a necessary physiological phenomenon. Pathological senile involution is an evidence of impairment of True Qi of internal human body. Human vital action is a changing process of life, senility, sickness, and death. In other words, this is a natural process of being full and decreasing of Vital Essence and Energy in kidney, and True Qi of human body decides this process. The Vital Essence and Energy in kidney vary, and they are influenced and restricted by various elements. The time of a senile involution varies individually. Human body protects and makes efforts not to leak out True Qi in effective ways. We can postpone a limit of time of physiological senile involution phenomenon. This is called 'Health Preservation' - resistance against senile involution.

• The Korean Journal of Applied Statistics
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• v.15 no.1
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• pp.187-199
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• 2002

When the sample size is small, exact tests are often employed because the asymptotic distribution of the test statistic is in doubt. The advantage of exact tests is that it is guaranteed to bound the type I error probability to the nominal level. In this paper we review the methods of constructing exact tests, the algorithm and commercial software. We also examine the difference between exact p-values obtained from exact tests and true p-values obtained from the true underlying distribution.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1371-1374
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• 2009

According to depth cues of an image, the optical engine of the solid volumetric true 3D display can project a sequence of slices of a 2D image to corresponding display at a set of liquid shutters (LC) locating at different depth. A single DLP optical engine developed for a solid volumetric true 3D display consists of a lamp, reflector, color wheel, hollow integrator, relays, DMD, and projection lens. The simulation results show that the optical engine designed for single DLP volumetric true 3D display satisfies the requirements.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.625-634
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• 2010

The objective of this paper is to apply a new proposed accuracy indicator to quantify the true and false modes for Eigensystem Realization Algorithm using output-based responses. First, a discrete mass-spring system and a simply supported continuous beam were modelled using finite element method. Then responses are simulated under random excitation. Natural Excitation Technique using only response measurements is applied to compute the impulse responses. Eigensystem Realization Algorithm is employed to identify the modal parameters on the simulated responses. A new accuracy indicator, Normalized Occurrence Number-NON, is developed to quantitatively partition the realized modes into true and false modes so that the false portions can be disregarded. Numerical simulation demonstrates that the new accuracy indicator can determine the true system modes accurately.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.68-69
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• 2006

When an alloy such as Ni-W is liquid phase sintered, heavy solid W particles sedimentate to the bottom of the container, provided that their volume fraction is less than a critical value. The sintering process evolves typically in two stages, diffusiondriven macrosegregation sedimentation followed by true sedimentation. During macrosegregation sedimentation, the overall solid volume fraction decreases concurrently with elimination of liquid concentration gradient. However, in the second stage of true sedimentation, the average solid volume fraction in the mushy zone increases with time. It is proposed that the true sedimentation results from particle rearrangement for higher packing efficiency.

• The Mathematical Education
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• v.40 no.2
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• pp.291-315
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• 2001

There are some problems in the introduction of proof in middle school mathematics. Among the problems, one is the use of postulates and the another is the methods of proof how to connect a statement with others. The first case has been treated mainly in this note. Since proof means to state the reason logically why the statement is true on the basis of others which have already been known as true and basic properties, in order to prove logically, it is necessary to take the basic properties and the statement known already as true. But the students don't know well what are the basic properties and the statement known already as true for proving. No use of the term postulation(or axiom) cause the confusion to distinguish postulation and theorem. So they don't know which statements are accepted without proof or not accepted without proof, To solve this problems, it is necessary to use the term postulate in middle school mathematics. In middle school mathematics, we present same model of the introduction of proof which are used the postulates needed for the proof.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.105-108
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• 2019

A 4-year-old cat was referred for a suspected pulmonary mass. True diaphragmatic hernia presence was diagnosed via computed tomography (CT). There was a thin membrane covering the diaphragmatic defect. The membrane was thinner than the diaphragm. After contrast injection, the membrane was less enhanced than that of the normal diaphragm. The membrane was identified as a remnant of the parietal pleura. In addition, contrast-enhanced CT images provided clarity in viewing the herniated liver and falciform fat. A thinner membrane, covering the diaphragmatic defect, and attached to the thicker normal diaphragm, is considered a unique CT feature of true diaphragmatic hernia.