• Journal of IKEEE
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• v.12 no.4
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• pp.246-254
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• 2008

This paper represents a design of a 4 way SIMD processor with multi-thread and dual phase instruction pipeline. 8 threads can be performing in round-robin order, so any hazards can’t occur. The dual phase pipeline makes a pipeline operate as two pipelines, and it can fetch maximum 4 unit instructions at once. This variable length instruction set divide into first phase and second phase instructions, and with this function, complex branch and addressing can be executed at one clock cycle. This processor reduces the code size to quarter, pull out the doubled performance improvement than normal SIMD architecture.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.654-664
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• 2017

This paper proposed an unified dual-phase-shift (UDPS) control for dual active bridge (DAB) converters in order to improve efficiency for a wide output power range. Different operating modes of UDPS are characterized with respect to the reactive current distribution. The proposed UDPS has the same output power capability with conventional phase-shift (CPS) method. Furthermore, its implementation is simple since only the change of the leading phase-shift direction is required for different operating power range. The proposed UDPS control can minimize both the inductor rms current and the circulating reactive current for various voltage conversion ratios and load conditions. The optimal phase-shift pairs for two bridges of DAB converter are derived with respect to the comprehensive reactive power loss model, including the reactive components delivered from the load and back to the source. Simulation and experimental results are illustrated and explained with details. The effectiveness of the proposed method is verified in terms of reactive power losses minimization and efficiency improvement.

• Journal of Surface Science and Engineering
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• v.26 no.2
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• pp.63-70
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• 1993

The mechanical properties of ferrite-martensited dual phases steels are affected by the microstructural factors, such as martensited volume fractions, ferrite grain size, strength ratio, connectivity, etc. Two phase alloys are technologically important. However, there is a lack of understanding as to stress-strain behavior of dual phase alloy in terms of stress-strain behavior of each component phases. The lack of the understanding stems from the complex deformation behavior of two phase alloys. The aim of this study is to rationalize stress-strain behavior of dual phase alloy in terms of the stress-strain behavior of component phase by systematically considering all the factors listed above. It was found that for a given martensite volume fraction, the calculated stress-strain curve was higher for a finer particles size than for a coarse particle sized within the range of the strains considered, and this behavior was seen for all the different volume fraction alloys considered. The calculated stress-strain curves were compared with corresponding experimental curves, and in general, good agreement was found. The maximum difference in flow stress between the calculated and the experimental results occurs at the nearly beginning of the plastic deformation.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.78-86
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• 1988

In order to investigate the corrosion pit occurrence and growth characteristic of M.E.F.(martensite encapsulated islands of ferrite) dual phase steel was made with a suitable heat treatment of raw material(SS41), a corrosion fatigue test was performed under rotary bending in the salt solution having a concentration from 0.01 wt percent to 3.5 wt percent. The fatigue strength of dual phase steel was remarkably decreased with an increase in concentration of salt solution; approximately from 63% to 80% in case of dual phase steel and from 40% to 71% in case of raw material. Corrosion pit occurred in the martensite phase and fatigue cracks from corrosion pits were selectively propagated in martensite phases. In the observation of corrosion pits at the origin of fatigue cracks, it had been found that corrosion pits were grown into hemispherical pits and a/c(the surface diameter, 2c and the depth, a of corrosion pit)was about 1.0-1.5regardless of the variation of salt solution concentration. The difference of corrosion pit depth growth rate was increased with an increase in concentration of salt solution according to an increase in stress level.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1500-1511
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• 2017

The purpose of this paper is to study a high-performance control scheme for neutral-point-clamping three-level (NPC-3L) inverter fed dual three-phase permanent magnet synchronous motor (PMSM) drives by considering some asymmetric factors such as the non-identical parameters in phase windings. To implement this, the system model is analyzed for dual three-phase PMSM drives with asymmetric factors based on the vector space decomposition (VSD) principle. Based on the equivalent circuits, PI controllers with feedforward compensation are used in the d-q subspace for regulating torque, where the cut-off frequency of the PI controllers are set at the twice the fundamental frequency for compensating both the additional DC component and the second order component caused by asymmetry. Meanwhile, proportional resonant (PR) controllers are proposed in the x-y subspace for suppressing the possible unbalanced currents in the phase windings. A dual three-phase space vector modulation (DT-SVM) is designed for the drive, and the balancing factor is designed based on the numerical fitting surface for balancing the DC link capacitor voltages. Experimental results are given to demonstrate the validity of the theoretical analysis and the proposed control scheme.

• Journal of Advanced Navigation Technology
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• v.6 no.3
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• pp.188-194
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• 2002

DBS is utilized as very useful media in information-oriented society because it covers wide service area and provide high quality services. But DBS needs skill that can receive DBS signal at move. In this paper, it is considered a development of a device to receive DBS and design of a low noise downconverter that use tracking antenna to receive DBS at mobiles unit and ships which navigate in Korea peninsula coast. The structure of dual phase LNB is composed of LNA, BPF, oscillator, mixer, and IF amplifier. And for the position tracking, two input-output phase performed in phase. Measured results showed good performance that with respect to input signal 11.7 GHz~12.2 GHz, noise figure is 0.87 dBmax and conversion gain 62 dB, temperature characterization ${\pm}400$ kHz in respect to - 30 to $60^{\circ}C$, and phase noise -101 dBc/Hz in respect to offset 100 kHz.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.9
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• pp.380-387
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• 1986

We have developed a dual control algorithm by means of innovations approach and established the stability of dual by introducing the pole-placement method suggested by Berger on the non-dual control. The dual controller realizing this algorithm decreases control loss sharply when compared with that of a non-dual controller, and shows the characteristics of suppressing the output deviation in transient state effectively. The total control energy and the accumulated square misdistance of this dual controller are shown to be 1-10% and 0.1-10% of those of CE control, respectively. Consequently this controller solves the non-minimum phase problem encountered when discretizing the system equation, and can be used to overcome the uncertainty of system effectively by adjusting the learning rate of the controller.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.3
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• pp.223-229
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• 1981

A study has been made of the fracture strength and ductility of the dual phase microstructure, in which the martensitic phase encapsulated islands of ferritic phase in association with the cleavage cracking of ferrite grains. It was found the final fracture occured in a brittle manner, starting from the Griffith crack which consisted of the cleavage crack in the ferrite grains and the cracks in second phase. Furthermore, the effects of the ferrite grain sizes on the Griffith crack were also discussed.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.181-182
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• 2003

A preconditioned numerical method for gas-liquid to-phase flow is applied to solve cavitating flow. The present method employs a density based finite-difference method of dual time-stepping integration procedure and Roe's flux difference splitting approximation with MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. The method permits simple treatment of the whole gas-liquid two-phase flow field including wave propagation, large density changes and incompressible flow characteristics at low Mach number. By this method, two-dimensional internal flows through a venturi tuve and decelerating cascades are computed and discussed.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.163-166
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• 1999

In this paper, frequency synthesizer that can be used in IMT-2000 was designed and fabricated using dual loop PLL(Phase Locked Loop). For improving phase noise characteristic Voltage Controlled Oscillator was fabricated using coaxial resonator and eliminated frequency divider using SPD as phase detector and increased open loop gain. Fabricated frequency synthesizer had 1.82㎓ center frequency, 160MHz tuning range and -119.73㏈c/Hz low phase noise characteristic.