• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.101-109
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• 2008

The stability of a rotating cantilever pipe conveying fluid with a crack and tip mass is investigated by the numerical method. That is, the effects of the rotating angular velocity, mass ratio, crack severity and tip mass on the critical flow velocity for flutter instability of system are studied. The equations of motion of rotating pipe are derived by using the Euler-Bernoulli beam theory and the extended Hamilton's principle. The crack section of pipe is represented by a local flexibility matrix connecting two undamaged pipe segments. Also, the crack is assumed to be in the first mode of fracture and always opened during the vibrations. When the tip mass and crack are constant, the critical flow velocity for flutter is proportional to the rotating angular velocity of pipe. In addition, the stability maps of the rotating pipe system as a rotating angular velocity and mass ratio ${\beta}$ are presented.

• Advances in concrete construction
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• v.7 no.3
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• pp.131-141
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• 2019

Irregular distribution of mass in elevation is regarded as a structural irregularity by which the modes with high energy levels are excited and in addition, it can lead the structure to withstanding concentration of nonlinear deformations and consequently, suffer from unpredictable local or global damages. Accordingly, with respect to the lack of knowledge and insight towards the performance of concrete buildings making use of tunnel-form structural system in seismic events, it is of utmost significance to assess seismic vulnerability of such structures involved in vertical mass irregularity. To resolve such a crucial drawback, this papers aims to seismically assess vulnerability of RC tunnel-form buildings considering effects of irregular mass distribution. The results indicate that modal responses are not affected by building's height and patterns of mass distribution in elevation. Moreover, there was no considerable effect observed on the performance levels under DBE and MCE hazard scenarios within different patterns of irregular mass distribution. In conclusion, it appears that necessarily of vertical regularity for tunnel-form buildings, is somehow drastic and conservative at least for the buildings and irregularity patterns studied herein.

• Journal of the Korean Data and Information Science Society
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• v.17 no.4
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• pp.1289-1297
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• 2006

Before other statistical data analysis the preprocessing steps should be performed adequately to have meaningful results. These steps include processes such as baseline correction, normalization, denoising, and multiple alignment. In this paper an algorithm for baseline correction is proposed with using the piecewise cubic Hermite interpolation with block-selected points and local minima after denoising for SELDI or MALDI mass spectrometry data.

• Publications of The Korean Astronomical Society
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• v.2 no.1
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• pp.30-38
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• 1985

We derived initial mass functions (IMF) of massive stars in three different regions of spiral arms within 2.5kpc from the sun. The derived IMF slope $\beta$ of Local arm stars is found to be $-2.09{\sim}-2.06$, very close to that of Bisiacchi et al. (1983). For Sagittarius-Carina arm stars $\beta$ ranges from -1.77 to - 1.72 which is close to that of overall stars given by Germany et al. (1982). Possible causes inducing the regional difference in IMFs are discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.265-272
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• 2001

Excavation in a big city is different from excavation in a local area because construction methods and stability are directly connected in a loss of life. Especially, estimate of rock mass slope stability is excuted by more detail and safty work. In this study, we are made reserches in rock mass slope stability and safety method that the slope is closed by elementary school in a big city. The result of many field study and numerical analysis is shown up direct reinforcement used to anchor.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.250-253
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• 2018

Schwannomas originating from the external auditory canal are relatively uncommon whereas they are commonly found in head and neck region. The authors recently experienced a 18-year-old male with a large mass in his right side external auditory canal. The mass was reported as a schwannoma and after the local excision, no symptom or sign of recurrence was identified. We report the case with literatures.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.24-29
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• 2006

In this paper, the effect of open crack on the dynamic behavior of simply supported Timoshenko beam with a moving mass was studied. The influences of the depth and the position of the crack on the beam were studied on the dynamic behavior of the simply supported beam system by numerical methods. The equation of motion is derived by using Lagrange's equation. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. The crack is modeled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces on the crack section and is derived by applying fundamental fracture mechanics theory. As the depth of the crack increases, the mid-span deflection of the Timoshenko beam with a moving mass is increased.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.277-294
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• 2018

In the space industry, structures undergo several vibration and acoustic tests in order to verify their design and give confidence that they will survive the launch and other critical in-orbit dynamic scenarios. At component level, vibration tests are conducted with the aim to reach local or global interface loads without exceeding the design loads. So, it is often necessary to control and limit the input based on a load criterion. This means the test engineer should be able to assess the interface loads, even when load cannot be measured. This paper presents various approaches to evaluate interface loads using measured accelerations and by referring to mass operators. Various methods, from curve fitting techniques to finite element-based methods are presented. The methods are compared using signals with known imperfection to identify strengths and weaknesses of each mass operator definition.

• Journal of Veterinary Clinics
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• v.21 no.2
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• pp.214-218
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• 2004

A 16-month old female Golden retriever dog was presented with a 2-week history of left-sided exophthalmos, third eyelid prominence, some scale of the trunk, mild anorexia, mild diarrhea and depression. In radiographic findings, a mass with increased opacity in the left retrobulbar area was observed. Cytologic and histopathologic examinations after enucleation and mass excision showed diffuse round cell accumulation and adjacent small area of elongated cell proliferation were shown. They also illustrated the neoplastic cells with large nucleoli, multiple nucleoli that differ in size and scant cytoplasm with several clear vacuoles. Extent of local invasiveness and central necrosis of the retrobulbar mass was identified by magnetic resonance imaging. Based on the physical and laboratory examination, radiographic, cytologic and histopathologic findings this case was diagnosed as extranodal malignant lymphoma of the retrobulbar area.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.79-86
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• 2011

The dynamic instability and natural frequency of elastically restrained pipe conveying fluid with the attached mass and crack are investigated. The pipe system with a crack is modeled by using extended Hamilton's Principle with consideration of bending energy. The crack on the pipe system is represented by a local flexibility matrix and two undamaged beam segments are connected. In this paper, the influence of attached mass, its position and crack on the dynamic stability of a elastically restrained pipe system is presented. Also, the critical flow velocity for the flutter and divergence due to the variation in the position and stiffness of supported spring is studied. Finally, the critical flow velocities and stability maps of the pipe conveying fluid with the attached mass are obtained by the changing parameters.