• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.5
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• pp.509-520
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• 2020

Currently, the criteria for input motions used in dam seismic design are clearly presented in general provisions of seismic design (KDS 17 10 00), and seismic ground motion records should be matched to the standard design response spectrum. However, the effect on the results is not assessed according to the selection of the seismic ground motion records, making it difficult to select seismic input motions. Therefore, in this study, the change in the amount of crest settlement of an embankment dam was assessed through numerical analysis after matching the seismic ground motion records of domestic and overseas earthquakes in accordance with the standard design response spectrum provided in the seismic design code (KDS 17 10 00). The results showed that the behavior of the upper part of the embankment, such as maximum acceleration at the crest and amplification through the dam, rather than the effect of free-field acceleration, had a greater effect on the amount of crest settlement. Moreover, it was confirmed that even an input seismic motion matched to the standard design response spectrum can make a difference in settlement depending on the characteristics of amplification through a dam body.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.249-254
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• 2009

In our study, the Hanle spectrum and nonlinear magneto-optic effect (NMOE) signals were observed as a function of magnetic field on $D_1$ line of $^{87}Rb$ atoms contained in a paraffin coated vapor cell. We observed the double structure from the Hanle and the NMOE spectrum in the paraffin coated Rb vapor cell. The narrow spectral width of the narrow resonance signal is approximately 1 kHz and the magnitude is approximately 10 percent of the total spectrum. Also, the NMOE signals corresponding to the Hanle configuration consisted of two different dispersion-like features. At the near zero magnetic field, a sharp slope signal was centered, and its value was 10 mV/${\mu}T$ with laser power was $200{\mu}W$.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.129-134
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• 2002

The seismic performance evaluation and retrofit process are very important for old bridge. If the result is not appropriate, a retrofit process requires. Among the various retrofit methods, this paper selects a seismic isolator and evaluates a seismic performance of bridge. In case of applied seismic isolators to bridge, it proved that seismic capacity is increased by isolators A period of bridge is increased, and a seismic response is decreased. A method of evaluation is capacity spectrum method. By means of a graphical procedure, capacity spectrum estimates a performance level of structure by comparing the capacity of structure with the demand of earthquake ground motion on the structure. The objective of this study is to compare a seismic performance of a non-seismic designed bridge and seismic isolated bridge and to verify a effect of seismic isolator

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.155.1-155.1
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• 2015

Nowadays, Plasma has been used in biological, medical such as wound healing, plant grow, killing cancer. When plasma generated, UV light and ROS(Reactive oxygen species), RNS(Reactive nitrogen species) can generated and those things effect to biological material. So we made simple plasma device using needle type of electrode and generated plasma. We used three kinds of gas and measured applied voltage and current. Also we observed optical emission spectrum. Using deuterium ramp, we can observed absorption spectrum and calculated radical density by lambert-beer's law. It is around ~1016cm3. And we can see the time-resolved absorption spectrum from monochromator, PMT(photo multiply tube), IV-converter, oscilloscope.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.85-92
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• 2000

The pulsating pressure waves are composed of fundamental frequency and higher order harmonics in exhaust pipe of engines. The nonlinearity in exhaust pipe is caused by their interactions. The error which is between prediction and measurement is induced by the nonlinearity. We can not explain this phenomenon using linear acoustic theory which is existing theory. So power spectrum which was used in linear theory is not useful. Bispectrum and bicoherence functions which are a higher order spectrum are applicable to explain this phenomenon. This paper proposes a nonlinear effect of pulsating pressure waves. The phenomenon proposed here is identified by using of higher order spectrum density functions.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.287-293
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• 2007

The researchers have studied for a long time about the depth of anesthesia but they don't make criteria for the depth of anesthesia. Anesthetists can't make a prediction about patient's reaction. Therefore, patients have potential risk such as poisonous side effect, late-awake, early-awake and strain reaction. In this study, the distributed characteristics on the bispectrum and bicoherence, the type of nonlinear signal processing, as a result of the coupling of EEG were presented according to depth of anesthesia. These results were consistent with a trend of delta ratio that the index of evaluation for the depth of anesthesia. The higher-order spectrum (HOS), the bispectrum and bicoherence, gives the useful information about depth of anaesthesia than other indexes.

• Journal of Life Science
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• v.10 no.5
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• pp.519-523
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• 2000

The action spectrum for light-induced growth of fruit body in Pleurotus ostreatus has been studied by irradiation at various wavelengths. Effective wavelengths were distributed from near ultraviolet to blue region of spectrum. The most effect of light was observed in the region between 340 to 520 nanometers. The growth weigth obtained from which has been irradiated 144 hours in the region of 340-520 nm increases 74%, on the contrary the observed growth weight has been observed in the longer wavelengths than 620 nm. The pileus size was promoted 30$\times$32% in the region of 340-500 nm, and retarded 22$\times$19% in the dark. the strip length was rearded 12% in the region of 340-500 nm, and promoted 38% in the dark. The color thickness for pileus is getting light in longer wavelengths.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.251-255
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• 2011

In this paper, we investigate an adaptive cognitive radio (CR) scheme where a sensing duration and a detection threshold for spectrum sensing are adaptively determined according to the channel condition in a fading channel. We optimize the sensing duration and detection threshold of a secondary user to maximize the performance of the secondary user guaranteeing a primary user's secure communication. In addition, we analyze the effect of channel fading on the optimization of the sensing duration and detection threshold. Our numerical results show that the performance of the adaptive CR scheme can be drastically improved if a secondary user can take the advantage of channel information between primary and secondary users.

• Journal of the Korean Mathematical Society
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• v.42 no.1
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• pp.65-83
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• 2005

In this paper, we prove that the two well-known natural normalizations of Hamiltonian functions on the symplectic manifold ($M,\;{\omega}$) canonically relate the action spectra of different normalized Hamiltonians on arbitrary symplectic manifolds ($M,\;{\omega}$). The natural classes of normalized Hamiltonians consist of those whose mean value is zero for the closed manifold, and those which are compactly supported in IntM for the open manifold. We also study the effect of the action spectrum under the ${\pi}_1$ of Hamiltonian diffeomorphism group. This forms a foundational basis for our study of spectral invariants of the Hamiltonian diffeomorphism in [8].

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.4
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• pp.67-77
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• 2002

This paper introduces the calibration results of the fatigue crack growth models for damage tolerance analysis of the aircraft structures. Generalized Willenborg model and Wheeler model are calibrated with experimental data tested under the load spectrum of a trainer. The retardation factors such as, shut-off ratio in Generalized Willenborg model and shaping exponent in Wheeler model, are evaluated for aluminum alloys AL2024-T3511, AL7050-T7451 and AL7075-T73511. It is shown that the retardation effect of the crack growth rate depends on the yield strength of material and the maximum stress in the load spectrum. Generalized Willenborg model and Wheeler model give satisfactory prediction of crack growth life but the calibration of the experimental parameters with test is required.