• Korean Journal of Social Welfare Studies
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• v.47 no.3
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• pp.139-159
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• 2016

This study aims to investigate the wage gap between male and female workers at social welfare institutions and to determine its factors. For this purpose, a Blinder-Oaxaca decomposition and regression models are applied to analyze wage survey data. The results are as follows. Firstly, the gender wage gap of social workers is a bit smaller, compared to the average of wage earners. Secondly, about two-thirds of wage gap is due to differences in productivity(endowment) factors; the other part is due to discrimination. Thirdly, the most important cause of gender wage gap is career disruptions of female workers largely due to marriage and birth. Fourthly, other causes of gender wage gap include differences in education, in job grade, in employment status, and in the characteristics of institutions. Finally, among the discriminating factors worsening gender wage gap, a key factor is a gender discrimination in the compensation for age.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.397-408
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• 2015

Purpose: Express mail service(EMS) supplied by 'Korea POST'is an international postal service which brings letters, documents and parcels to a destination abroad in the fastest and safest way. This service is in a tough competition with global companies such as TNT, FedEx, DHL or UPS. To build an effective strategy for being competitive, an intensive study on EMS service quality should be accomplished from a customer's perspective. Methods: Kano model and improvement gap analysis are used to categorize and prioritize EMS service quality attributes. A 5-point Lickert scale is employed to apply the Kano model and improvement gap analysis. Each quality attribute can be classified as weak in comparison with competitors, critical for improvement, or potentially competitive. Results: Price, on-time delivery and delivery quality are to be kept as is; fast delivery, parking convenience and staff expertise can be potentially competitive; and the other attributes are considered to be critical for improvement. Conclusions: Fast reimbursement and proper compensation when shipping items are lost or damaged are to be improved with high priority. Efforts to secure fast delivery, parking convenience and staff expertise are needed to be competitive in the future.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.276-280
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• 2001

The quality of images displayed by using an LC projector is strongly influenced by the cell-gap variations over LC panels, the essential components of the projector. We show that such influence can be relieved by introducing slit patterns in the pixel electrodes in the LC panels. The improvement comes from the compensation of the influence of cell-gap variations by optical anisotropy variations arising from the lateral components of the electric field generated by the slit patterned electrodes. Simulations show that cell-gap tolerance can be increased by more than 50% by introducing the slit patterns. This method can be used in TN mode LC panels, which use LC's with positive dielectric anisotropy. tropy.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.15-17
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• 2006

This paper proposes a compensation method for an air gapped current transformer (CT) in the steady state. An air gapped CT is used in order to reduce a remanent flux in the case of auto-reclosure. It causes larger ratio and angle errors than the closed core CT because the magnetizing inductance of an air-gapped CT is even smaller than the closed-core CT. The core flux is calculated and used to estimate the exciting current in accordance with the hysteresis curve of the air-gapped CT The correct current is obtained by adding the estimated exciting current to the measured secondary current. The performance of the method was investigated for the air gapped CTs with a gap of 0.083mm and 0.249mm for the 120%, 100% and 20% of the rated current. Various test results indicate that the proposed compensation algorithm can improves the accuracy significantly.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.4
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• pp.503-510
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• 2003

A new method of induction motor drive, which requires neither shaft encoder nor speed estimator, is presented. The proposed scheme is based on decreasing current gap between a numerical model and an actual motor. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing the current difference. the rotor approaches to the model speed. that is. reference value. The indirect field orientation algorithm is employed for tracking the model currents. The performance of induction motor drives without speed sensor is generally characteristic of poorness at very low speed. However, in this system, it is possible to obtain good speed response in the extreme low speed range.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.930-936
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• 2003

A new method of direct current motor drive, which requires neither shaft encoder nor speed estimator, is presented. The proposed scheme is based on decreasing current gap between a numerical model and an actual motor. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing the current difference, the rotor approaches to the model speed, that is, reference value. The performance of direct current motor drives without speed sensor is generally poor at very low speed. However, in this system, it is possible to obtain good speed performance in the low speed range.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.132-139
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• 2001

In this research, we have developed a load/unload device capable of correcting the position automatically. Characteristic technologies such as compensation, control, guidance and communication have been modified and implemented on an existing electromagnetic guided AGV, helping to realize open system and distributed cooperation. We have applied the developed AGV with remote control and heterogeneous load/unload mechanisms in a machining system composed of various equipment such as machining centers, CMN and AS/RS and found that the AGV provided position error within $\pm$2mm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.780-785
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• 2001

A moving-magnet type pickup actuator is proposed, which has the back-yoke to improve th sensitivity. Through the magnetic path analysis, we can find that the flux density is increased i the air gap by the pole assignment of magnet and the adding of back-yoke can reduce the flu leakage and induce 40％ up of flux density. Experimental results show that the sensitivity i improved in the tracking direction, however, the improvement doesn't occur in the focusing direction. Finally, the compensation performance is tested in HD-DVD system. And it is verifie that the actuator can compensate the disc tilt of ${\pm}$0.7$^{\circ}$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.837-842
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• 2007

Information storage devices using disks have a disk vibration at the frequency which is equivalent to the disk rotational speed. They also have a track vibration due to the disk eccentricity at the same frequency. In near field recording systems, the former affects the air-gap servo and the latter affects the tracking servo. In this paper, we introduce a novel control algorithm based on the internal model principle to both servos. A controller block designed by the principle is connected to the base lead-lag type compensator in parallel in order to cancel the repeatable run-out due to the disk vibration or eccentricity. Simulation and practical application of the algorithm on a near field recording system show good servo performance.

• Journal of Magnetics
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• v.17 no.2
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• pp.115-123
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• 2012

Contactless electrical power transfer through an air gap is a revived technology for supplying energy to many movable applications including Maglev. In this paper, magnetic equivalent circuits and analytical models of contactless electrical power transfer systems are developed and evaluated through experiment. Overall coupling coefficient and overall efficiency are introduced as means for evaluating the systems' performance. Compensating capacitors in primary and secondary sides of the systems improve the overall coupling coefficient and overall efficiency. Using the analytical models, the effects of different parameters and variables such as air gap and load current are analyzed to give a high coupling coefficient and an improved efficiency of power transfer for different compensation structures.