• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.49-61
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• 2005

The dynamic modulus of hot mix asphalt can be determined according to the different combinations of testing temperature and loading frequency. The superposition rule is adapted to get the master curve of dynamic modulus for each hot mix asphalt. There are couple of different methods to get the shift factor which is a key for making the master curve. In this paper, Arrehnius, 2002 AASHTO, and experimental method was employed to get the master curve. Evaluation of dynamic modulus for 25mm base course of hot mix asphalt with granite aggregate and two asphalt binders(AP-3 and AP-5) was carried out. Superpave Level 1 Mix Design with gyratory compactor was adopted to determine the optimum asphalt binder content(OAC) and the measured ranges of OAC were between 4.1% and 4.4%. UTM was used for laboratory test. The dynamic modulus and phase angle were determined by testing on UTM, with 5 different testing temperature(-10, 5, 20, 40, & $55^{\circ}C$) and 5 different loading frequencies(0.05, 0.1, 1, 10, 25 Hz). Using the measured dynamic modulus and phase angle, the input parameters of Sigmoidal function equation to represent the master curve were determined and these will be adopted in FEM analysis for asphalt pavements. The shift factor and activation energy for determination of master curve were calculated.

• Journal of Astronomy and Space Sciences
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• v.36 no.3
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• pp.133-147
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• 2019

Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) $B_Z$ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ${\sim}58^{\circ}$ coinciding with the minimum SymH and dayside at ${\sim}59^{\circ}$ compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF $B_Z$ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.11-18
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• 2014

Most of the energy efficient MAC protocols for wireless sensor networks (WSNs) are based on duty cycling in a single channel and show competitive performances in a small number of traffic flows; however, under concurrent multiple flows, they result in significant performance degradation due to contention and collision. We propose a multi-channel pipelining (MCP) method for convergecast WSN in order to address these problems. In MCP, a staggered dynamic phase shift (SDPS) algorithms devised to minimize end-to-end latency by dynamically staggering wake-up schedule of nodes on a multi-hop path. Also, a phase-locking identification (PLI) algorithm is proposed to optimize energy efficiency. Based on these algorithms, multiple flows can be dynamically pipelined in one of multiple channels and successively handled by sink switched to each channel. We present an analytical model to compute the duty cycle and the latency of MCP and validate the model by simulation. Simulation evaluation shows that our proposal is superior to existing protocols: X-MAC and DPS-MAC in terms of duty cycle, end-to-end latency, delivery ratio, and aggregate throughput.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.233-244
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• 2005

Guanosine fermentation process can be well predicted and analyzed by the proposed state equations describing the dynamic change of a bioreactor. Pyruvate and alanine were found to be characteristically accumulated along with the decline of the guanosine formation rate during the mid-late phase of the process. The enzymological study of the main pathways in glucose catabolism and the quantitative stoichiometric calculation of metabolic flux distribution revealed that it was entirely attributed to the shift of metabolic flux from hexose monophosphate (HMP) pathway to glycolysis pathway. The process optimization by focusing on the restore of the shift of metabolic flux was conducted and the overcoming the decrease of oxygen uptake rate (OUR) was taken as the relevant factor of the trans-scale operation. As a result, the production of guanosinewas increased from 17 g/L to over 34 g/I.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.176-182
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• 2009

We surveyed the total 30 sites in Gilgol, Nae Sorak for the patterns of the natural regeneration of the korean fir in connection with the characteristic of the stand. The natural regeneration in a forestrical meaning is not found in natural forest but mainly in the anthropogenically already disturbed area. It may be inferred from this fact that the anthropogenic disturbance can give more better condition for a natural regeneration. The regeneration phase in the natural forest is not so distinctive as the artificial forest, and shows itself transiently. And it may be also said that a shift in generation is only a part of the change of the stand phase. The concept of the natural regeneration will lose its meaning, in so far as the patch dynamic determines the phase of the stand, and the main tree species are shade-tolerant abies.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.1
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• pp.126-136
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• 1992

In this paper, a simple structured feedback compensation scheme for a electro-hydraulic servo system to keep the response characteristics unchanged regardless of the load variation is proposed. In electro-hydraulic servo system, servovalve is most important control element. But the relation between input corrent and output flowrate of the servovalve has properties as follows; firstly, in spite of constant input current, output flowrate decreases as load pressure increases, secondly, according to frequency response of typical servovalve, the characteristics of gain and phase shift is something like 2'nd order system. Load pressure feedback compensation method has been applied to eliminate the first influence, the second influence has been improved by phase lead compensation method. As a result of above compensation methods, regardless of variation load condition, spring and inertia load, the compensation scheme has been verified to be effective within the range of frequency less than 25Hz by static response and dynamic response in time domain and frequency domain through experiments.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.361-363
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• 1999

This paper proposes an SSSC based on 3-level half-bridge inverters. The dynamic characteristic of the proposed SSSC was analyzed by EMTP simulation, assuming that the SSSC is inserted in the transmission line of the one-machine-infinite-bus power system. The proposed SSSC has six 3-level half-bridge inverters per phase, which operates in PWM mode. The proposed SSSC generates a quasi-sinusoidal output voltage by 90 degree phase shift to the line current. The proposed SSSC does not require the coupling transformer for voltage injection, and has a flexibility in operation voltage by increasing the number of series connection.

• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.416-423
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• 2000

A new demodulation technique which can be used for the fiber optic acoustic sensor system using Sagnac interferometer is described. The theoretical limitation in dynamic range of the quadrature demodulation technique can be removed by the proposed BPSK(Binary Phase Shift Keying) demodulation technique. Full demodulation of input acoustic signal is possible with just simple electronics by eliminating the necessity of the high frequency phase modulation. This technique is suitable for digital signal processing of fiber optic sensor systems and can be applicable for other interferometers.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.6
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• pp.296-302
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• 2001

This paper proposes a SSSC based on multi-bridge inverters. The dynamic characteristic of the proposed SSSC was analyzed by EMTP simulation and a scaled hardware model, assuming that the SSSC is inserted in the transmission line of the one-machine-infinite-bus power system. The proposed SSSC has 6 multi-bridge inverters per phase, which generates 13 pulses for each half period of power frequency. The proposed SSSC generates a quasi-sinusoidal output voltage by 90 degree phase shift to the line current. The proposed SSSC does not require the coupling transformer for voltage injection, and has a flexibility in operation voltage by increasing the number of series connection.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.685-688
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• 2001

This paper proposes an SSSC based on multi-bridge inverters. The dynamic characteristic of the proposed SSSC was analyzed by EMTP simulation and a scaled handware model, assuming that the SSSC is inserted in the transmission line of the one-machine-infinite-bus power system. The proposed SSSC has 6 multi-bridge inverters per phase, which generates 13 pulses for each half period of power frequency. The proposed SSSC generates a quasi-simusoidal output voltage by 90 degree phase shift to the line current The proposed SSSC does not require the coupling transformer for voltage injection, and has a flexibility in operation voltage by increasing the number of series connection.