• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.463-466
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• 2000

According to the development of the semiconductor micro device technology, IC chip trends the high integrated, low power tendency. Nowadays, it can be showed the tendency of single chip in system level. But in the system level, IC operates by multi power supply voltages. So, semiconductor process is necessary for these multi power operation. Therefore, in this paper, dual gate high voltage device that operate by multi power supply of 5V and 20V fabricated in the 0.5${\mu}{\textrm}{m}$ CMOS process technology and its electrical characteristics were analyzed. The result showed that the characteristics of the 5V device almost met with the SPICE simulation, the SPICE parameters are the same as the single 5V device process. And the characteristics of 20V device showed that gate length 3um device was available without degradation. Its current was 520uA/um, 350uA/um for NMOS, PMOS and the breakdown voltages were 25V, 28V.

• 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 Construction Engineering and Project Management
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• v.2 no.2
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• pp.28-35
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• 2012

Critical to project success is effective stakeholder management. This paper presents a challenge for the project manager who uses traditional approaches to manage mid-level stakeholders in an organization. Dual roles of a mid-level stakeholder (as a stakeholder of a project and as an agent of the corporate) may cause problems that would result in difficulties for project managers in identifying the stakeholder's attributes and overcoming hierarchical authority expectation. However, the dual roles of the stakeholder result in its weakness in the project-stakeholder relationship. Can a project leverage its strategic role for effective upward influence by linking project objectives to corporate strategic objectives? To address this research question, case study method was used to gain a deeper understanding of mid-level stakeholder's salience. This research proposes an upward influence strategy to embed a project-stakeholder relationship in a hierarchical stakeholder network.

• PNF and Movement
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• v.15 no.3
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• pp.361-371
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• 2017

Purpose: The purpose of this study was to examine the effects of performing a dual task on gait velocity, temporospatial variables, and symmetry in subjects with subacute stroke. Methods: The study included 14 independent community ambulators with gait velocity of 0.8m/s. The Korean mini-mental state examination, the Berg balance scale, the Trunk impairment scale, and the Fugl-Meyer assessment scale were used to recruit homogeneous subjects. Subjects performed a single task (10m ambulation at a comfortable speed) and a dual task (10m ambulation at a comfortable speed while carrying a water-filled glass). Gait variables were examined with the OptoGait system. Results: The findings of this study were as follows: 1) Gait velocity decreased significantly in the dual-task condition as compared to the single task condition. 2) There were no significant differences between the paretic and non-paretic stances. 3) Paretic swing decreased significantly in the dual-task condition as compared to the single task condition. 4) The non-paretic, double-limb support phase increased significantly in the dual-task condition as compared to the single- task condition. 5) There was no significant difference in temporal symmetry. 6) Non-paretic step length decreased significantly in the dual-task condition as compared to the single-task condition. 7) There was no significant difference in spatial symmetry. Conclusion: Performing dual tasks decreases gait velocity, paretic swing phase, and non-paretic step length, while it increases non-paretic double limb support. In addition, although there is no difference in temporospatial symmetry, there is high inter-subject variability in temporospatial symmetry. Thus, dual tasks should be selected in accordance with the functional level of the hemiplegic patient, and inter-subject variability of the individual should be considered when dual tasks are considered for gait-training of hemiplegic patients.

• Journal of Power Electronics
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• v.17 no.1
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• pp.67-75
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• 2017

Due to the excessive zero-sequence voltage in dual three-level inverter fed open-end winding induction motor systems, zero-sequence circumfluence which is harmful to switching devices and insulation is then formed when operating in a single DC voltage source supplying mode. Traditionally, it is the mean value instead of instantaneous value of the zero-sequence voltage that is eliminated, through adjusting the durations of the operating vectors. A new strategy is proposed for zero-sequence voltage elimination, which utilizes unified voltage modulation and a decoupled SVPWM strategy to achieve two same-sized equivalent vectors for an angle of $120^{\circ}$, generated by two inverters independently. Both simulation and experimental results have verified its efficiency in the instantaneous value elimination of zero-sequence voltage.

• Journal of Power Electronics
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• v.15 no.4
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• pp.910-919
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• 2015

The use of a PV grid-connected inverter with non-isolated topology and without a transformer is good for improving conversion efficiency; however, this inverter has become increasingly complicated for eliminating leakage current. To simplify the complicated architecture of traditional three-level dual buck inverters, a new dual Buck three-level PV grid-connected inverter topology is proposed. In the proposed topology, the voltage on the grounding stray capacitor is clamped by large input capacitors and is equal to half of the bus voltage; thus, leakage current can be eliminated. Unlike in the traditional topology, the current in the proposed topology passes through few elements and does not flow through the body diodes of MOSFET switches, resulting in increased efficiency. Additionally, a multi-loop control method that includes voltage-balancing control is proposed and analyzed. Both simulation and experimental results are demonstrated to verify the proposed structure and control method.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.3
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• pp.207-212
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• 2005

Dual frequency acoustic pinger(AP) was manufactured to reduce study effect by long-term use of developed single frequency AP to prevent cetacean bycatch. Directivity characteristic of transducer was the omnidirectional pattern which showed less than ${\pm}3dB$ the change range of sensitivity on the beam pattern of right and left. Source power level(SPL) was 1384311pa with epoxy window before casing however after casing 1170B11Pa at sea. Dual frequency Af was tested to identify the avoidance behavior of bottlenose dolphin by its working. However the efficiency of dual frequency AP about the study effect was verified experiment repeatedly using single and dual frequency AP.

• Ocean and Polar Research
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• v.41 no.3
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• pp.193-202
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• 2019

There have been various approaches for efficiency improvement of a Darrieus tidal stream turbine after it was introduced as an alternative of horizontal axis turbines. Among the approaches, the researches on the interaction effect of dual configuration were conducted. In this study, a dual Darrieus turbine with a coupling mechanism was proposed for investigating the interaction effect. Also, the effect of bi-directional tidal stream was analyzed with prototype fabrication, apparatus set-up and experiment conduction in indoor and offshore facilities. As the results of the experiments, the dual turbine in case of counter-rotation and inflow between the turbines improved efficiencies by 9.5% and 11.31%, respectively, as compared to the single turbine. Also, the dual turbine in case of the inflow improved efficiencies by 9.4% and 16.62%, respectively, as compared to that in case of outflow between the turbines which represented the case of 180 degrees change of flow direction after slack water. Therefore, the proposed dual turbine showed the advantage in terms of the efficiency as compared to the single turbine and the effect level of the slack water on the performance of the dual turbine was investigated.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.3
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• pp.14-20
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• 2011

This study aims at aligning multiple wafers to reduce wafer handling time in wafer processes. We designed a multilevel structure for a prealigner which can handle multiple wafer simultaneously in a system. The system consists of gripping parts, kinematic parts, vacuum chucks, pneumatic units, hall sensors and a DSP controller. Aligning procedure has two steps: mechanical gripping and notch finding. In the first step, a wafer is aligned in XY directions using 4-point mechanical contact. The rotational error can be found by detecting a signal in a notch using hall sensors. A dual prealigner was designed for 300mm wafers and constructed for a performance test. The accuracy was monitored by checking the movement of a notch in a machine vision. The result shows that the dual prealigner has enough performance as commercial products.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.180-184
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• 2008

Preliminary results are reported on ship detection using coherence images computed from crosscorrelating images of multi-look-processed dual-polarization data (HH and HV) of ENVISAT ASAR. The traditional techniques of ship detection by radars such as CFAR (Constant False Alarm Rate) rely on the amplitude data, and therefore the detection tends to become difficult when the amplitudes of ships images are at similar level as the mean amplitude of surrounding sea clutter. The proposed method utilizes the property that the multi-look images of ships are correlated with each other. Because the inter-look images of sea surface are covered by uncorrelated speckle, crosscorrelation of multi-look images yields the different degrees of coherence between the images and water. The polarimetric information of ships, land and intertidal zone are first compared based on the cross-correlation between HH and HV. In the next step, we examine the technique when the dual-polarization data are split into two multi-look images.