• Journal for History of Mathematics
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• v.20 no.4
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• pp.93-104
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• 2007

It is well known that a suspension bridge may display certain oscillations under external aerodynamic forces. Under the action of a strong wind, in particular, a narrow and very flexible suspension bridge can undergo dangerous oscillations. The collapse of the Tacoma Narrows suspension bridge caused by a wind blowing at a speed of 42 miles per hour, is one of the most striking examples. In this paper, we study models describing oscillations in suspension bridges and known results.

• The Journal of Pediatrics of Korean Medicine
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• v.14 no.2
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• pp.169-184
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• 2000

A literature study was progressed for oriental medical treatment for atopic dermatitis. Atopic dermatitis is a chronic or chronically relapsing, pruritic dermatitis. In oriental medical treatment is classified into the treatment of inside(herb tea), treatment of outside(medicine for external application), treatment of inside & outside. The method of inside treatment is improving in health for the spleen and clearing wetness(健脾利濕), extinguishing wind and refreshing fever(消風淸熱), nourishing blood and making dryness gloss(養血潤燥). The method of outside treatment is refreshing fever and removing wetness(淸熱燥濕), counteracting the poison and getting rid of itch(解毒止痒), removing the boil and forming proud flesh(消腫生肌). The method of inside & outside is improving in health for the spleen and clearing wetness(健脾利濕), refreshing fever and getting rid of itch(淸熱止痒). refreshing blood and extinguishing wind(凉血祛風).

• Journal of Haehwa Medicine
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• v.14 no.1
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• pp.187-200
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• 2005

1. The causes of Tong Bi(痛痺) are divided into external cause(wind, cold, dampness) and internal cause(deficiency yang-excess yin, excess cold). but mostly two causes are combined. 2. Chronic Tong Bi can be turn into bone, kidney, zang organs disease and Hak Sul Pung(鶴膝風). 3. The symptoms are severe arthralgia, limit of ROM, localized coldness and edema, white coated tonge fur, wiry and knotted pulse. 4. The principles of medicinal treatment are mainly eliminating the cold and inducing the wind, removing the dampness. 5. The principle of acupucture and moxibustion treatment is mainly eliminating the cold(iron skin treatment, moxibustion, warming acupucture).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.165-172
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• 1996

Recently, the response of a high-rise building to external dynamic force created by wind and earthquake has received much attention. This response is dependent on wind intensity, surrounding environment, building size, shape, mass, stiffness and amount of energy dissipation available in the system. The study has been done on these parameters. Attempts have been made to increase the damping in building system and thereby reduce structural response. These attempts have centered on adding an energy-dissipative system(passive tuned mass damper; passive TMD) to the building system and increasing the overall effective damping. In this paper the optimum condition of passive TMD will be derived with respect to random excitation and the properties of the optimum condition will have been studied.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.495-500
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• 2001

The dynamic behavior of high speed train is very important because it should be safe and is satisfied with the ride comfort of passengers. The railway is composed of many suspension components-1st springs, 1st dampers, 2nd springs, 2nd dampers etc- that have an influence on the dynamic characteristics of high speed train. Also, the wheel/rail shapes, the track condition and geometry and many environmental factors-rain, snow, wind etc-are affected the dynamic behavior of high speed train. This paper is reviewed the effect of wind(gust) on the dynamic behavior of high speed train. Vampire program is used for this simulation. The result of simulation shows that high speed train should not be operated when the gust speed is beyond 34.5m/sec.

• Journal of Astronomy and Space Sciences
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• v.32 no.1
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• pp.1-11
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• 2015

Earth's magnetopause separating the fast and often turbulent magnetosheath and the relatively stagnant magnetosphere provides various forms of free energy that generate low-frequency surface waves. The source mechanism of this energy includes current-driven kinetic physical processes such as magnetic reconnection on the dayside magnetopause and flux transfer events drifting along the magnetopause, and velocity shear-driven (Kelvin-Helmholtz instability) or density/pressure gradient-driven (Rayleigh-Taylor instability) magnetohydro-dynamics (MHD) instabilities. The solar wind external perturbations (impulsive transient pressure pulses or quasi-periodic dynamic pressure variations) act as seed fluctuations for the magnetopause waves and trigger ULF pulsations inside the magnetosphere via global modes or mode conversion at the magnetopause. The magnetopause waves thus play an important role in the solar wind-magnetosphere coupling, which is the key to space weather. This paper presents recent findings regarding the generation of surface waves (e.g., Kelvin-Helmholtz waves) at the Earth's magnetopause and analytic and observational studies accountable for the linking of the magnetopause waves and inner magnetospheric ULF pulsations, and the impacts of magnetopause waves on the dynamics of the magnetopause and on the inner magnetosphere.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.55.1-55.1
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• 2019

We investigate broadband emission properties of the pulsar wind nebula (PWN) 3C 58 using a spectral energy distribution (SED) model. We attempt to match simultaneously the broadband SED and spatial variations and emission about 3C 58 in X-ray band. We further the model to explain a possible far-IR feature of which a hint is recently suggested in 3C 58: a small bump at ~10^11 GHz in the PLANCK and Herschel band. While external dust emission may easily explain the observed bump, it may be internal emission of PWNe implying an another additional population of particles. Although significance for the bump in 3C 58 is not higher than other PWNe, here we explore possible origins of the IR bump using the emission model and find that a population of electrons with GeV energies can explain the bump. If it is produced in the PWN, it may provide new insights into particle acceleration and flows in PWNe.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.498-504
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• 2018

The conventional photovoltaic(PV) systems are designed the installation angle for maximizing power output by considering a geographical characteristics, weather and climate conditions such as the solar radiation and atmosphere temperature. However, the PV generators must be designed to deal with the extreme situations like typhoons, earthquakes because PV systems are exposed to the ambient conditions and external shock due to condition of PV location. Especially, the wind has relatively higher influence on the design of PV systems, in this paper we proposed the method of determining the optimal nominal dimension of the facilities, which can withstand the maximum wind pressure. By using the proposed method, we determined the optimal installation angle for the aspect stability of PV facilities and amount of power output. Moreover, we analyzed the monthly amount of power for each installation angle of PV systems, and proposed the changing strategy of installation angle by determining the optimal angle to produce maximum power for each period.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.1
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• pp.50-59
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• 2000

This paper presents a brief outline of dynamic stability of a damaged ship at final stage of flooding in rough beam wind and waves. One degree-of-freedom, roll equation is adopted with effects of flooding water and external forces due to wind and waves, but without effect of sloshing. We discuss the dynamic stability of the damaged ship in terms of capsizing probability based on risk analysis, the method of which was firstly proposed by Umeda et al.[6] to high speed craft in intact condition. As a result, we can evaluate the dynamic stability of the damaged ship in probabilistic manner according to sea state, operating condition and damage situation.

• Journal of Power Electronics
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• v.16 no.2
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• pp.675-684
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• 2016

This paper presents a new stand-alone wind-based induction generator system with constant frequency and adjustable output voltage. The proposed generator consists of a six-phase cage-rotor induction machine with two separate three-phase balanced stator windings and a three-phase space vector pulse width modulation inverter that operates as a static synchronous compensator (STATCOM). The first stator winding is fed by the STATCOM and used to excite the machine while the second stator winding is connected to the generator external load. The main frequency of the STATCOM is determined to be constant and equal to the load-requested frequency. The generator output frequency is independent of the load power demand and its prime mover speed because the frequency of the induced emf in the second stator winding is the same as this constant frequency. A sliding mode control (SMC) is developed to regulate the generator output voltage. A second SMC is used to force the zero active power exchanged between the machine and the STATCOM. Some simulation and experimental results are presented to prove the validity and effectiveness of the proposed generator system.