• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.351-356
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• 2009

A dual-mode annular ring antenna for both global positioning system(GPS) and satellite digital multimedia broad-casting(DMB) is designed. The proposed antenna consists of a coupling feed line and four slots on the annular ring patch. The gap between the feed line and the annular ring patch is used for an input impedance matching, and the slot length is used for adjusting the resonant frequency of the $TM_{21}$ mode at the DMB frequency. The antenna was fabricated and measured. The experimental results show that the antenna resonants at the GPS and DMB frequencies with suitable bandwidths, and had a broadside radiation pattern at the GPS band and a conical beam radiation pattern at the DMB band.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1063-1066
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• 2003

This paper presents the design and characteristics analysis of axial-flux permanent-magnet (PM) synchronous generator of two air-gap. Dual axial-flux type PM synchronous generator commonly appears in applications where the generator axial dimension is more limited than the radial dimension. The strengths of dual axial-flux generator include ; (1) by employing two air-gaps, the rotor-stator attractive forces are balanced and no net axial or thrust load appeals on the generator hearings ; (2) heat produced by the stator windings appears on the outside of the generator, making it relatively easy to remove, and so on. In this paper, the simple magnetic equivalent circuit approach is used for initial design iteration, and the finite-element method is applied to analyze the detailed characteristics. The test results of driving characteristics are presented as well. The results are very similar to predicted performance of design.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.828-830
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• 2002

Axial Flux Permanent Magnet motor could widely be used for low speed and high torque applications. In this paper, to analyse the sensor positioning effect of AFPM motor which has a new concentric winding method and to calibrate the switching timing according to speed, prototype motor is manufactured. As a result of experiment, advance angle from 30 degree to 45 degree of sensor position is more proper. So, this results can be used for design of sensor position to improve characteristic of the dual gap AFPM with coreless and slotless.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1145-1148
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• 1999

This paper is introducing a newly developed spark gap switch with dual trigger system, into which the current from the voltage source is injected along wi th the test sequence during the synthetic testing of high voltage circuit-breaker.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.31-42
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• 2021

Several studies have been conducted on market orientation over the last three decades. However, the majority of previous research focused exclusively on an internal vision that conceives the market orientation from an organizational perspective, considering the market orientation as a strictly perceived culture or behavior by company's staff (managers and employees) .This study aims to emphasize the importance of analyzing the market orientation from a dual perspective by investigating simultaneously the perceptions of customers and those of managers. It examines the perceptual gap or perceptual congruence of market orientation between customers and managers. A survey is conducted with Tunisian bank managers and B to B customers to measure their market orientation perception. The results should reveal level of manager's market orientation in Tunisian banks compared to customers' perceptions. The perception gaps of market orientation between managers and customers named congruence is highlighted and categorized. This study provides some contributions to fill the gap emerging from the one-sidedness of market orientation evaluation and gives a dyadic vision of market orientation that helps managers in their continuous learning about markets and sensing customers' needs and expectations. Market orientation level between the two groups is evaluated to give some managerial recommendations.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.183-185
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• 2010

A 2.4 GHz dual-polarized antenna for a Doppler radar is studied. The proposed dual-polarized antenna using a stacked annular ring patch with two co-centric gap-coupled feed lines and a $90^{\circ}$ hybrid exhibits fairly good performance of 22 dB isolation at a center frequency of 2.4 GHz. Using a $90^{\circ}$ hybrid, a right-handed circular polarization for the transmitter and a left-handed circular polarization for the receiver are implemented. The gain of the designed antenna is about 0 dBi over operating frequencies. The antenna size including a ground plane is only $40{\times}40\;mm^2$.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.3
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• pp.33-46
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• 2007

This study deals with the adaptive multiuser OFDM (Orthogonal Frequency Division Multiplexing) system which adjusts the resource allocation according to the environmental changes in such as wireless and quality of service required by users. The resource allocation includes subcarrier assignment to users, modulation method and power used for subcarriers. We first develop a general optimization model which maximizes data throughput while satisfying data rates required by users and total power constraints. Based on the property that this problem has the 0 duality gap, we apply the subgradient dual optimization method which obtains the solution of the dual problem by iteration of simple calculations. Extensive experiments with realistic data have shown that the subgradient dual method is applicable to the real world system, and can be used as a dynamic resource allocation mechanism.

• Journal of Family Relations
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• v.22 no.3
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• pp.47-72
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• 2017

Objectives: Do husbands with working wives share domestic labor more equally than husbands with unemployed housewives? Is the husband's contribution sufficient enough to satisfy his wife? These questions have long inspired many researchers to find ways to more accurately estimate husband's domestic contributions and narrow the emotional gap following the different threshold of satisfaction within couples, but not without some limits. This study attempted to figure out an answer to the above-mentioned subject by using time diaries of Korean married couples with a preschooler as their first-born child and relying on the typology of husbands' sharing of housework and childcare, which allowed me to overcome some limitations of prior research. Method: I analyzed a total of 1,716 diaries of 858 married couples from 2014 Korea Time Use Survey with descriptive statistics, t-test, cluster analysis, and multinomial logit. Results: Analytic results showed that husbands in dual-earner households did share domestic labor more equally than husbands in single-earner households, but there were different types of husband's contribution depending on time they spent in housework and childcare. While more than half of husbands with employed wives shared more or less than ten percent of domestic labor, the rest were divided into one group of husbands who shared both housework and childcare more heavily and evenly, and another group who were mainly involved in childcare duties. It is interesting that husbands who made the least contributions to domestic labor were not the ones with the lowest level of satisfaction with their sharing of household labor, whereas their wives were deeply dissatisfied, leading to a huge emotional gap within couples. Conclusion: Identifying factors associated with the three different types allowed me to find a point of intervention to narrow the emotional gap that is likely to harm the marital relationship if left unattended to.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.301-306
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• 2004

In this study, Dual servo mechanism with VCM(Voice Coil Motor) and PZT is designed for a high precision force and position control. We designed the VCM actuator and dual servo mechanism with leaf spring. VCM actuators, with their high linearity, simple structure, low weight, and high efficiency, are increasingly being used in micro-positioning applications. There are many kinds of VCM with a structure. VCM actuators are divided into two types by moving parts. One is moving magnet type and the other moving coil type. We described the properties of these two types of VCM. Design parameters of VCM are defined through the FEM simulation analysis of magnetic field and dynamic model of dual servo mechanism. These researches help to for decreasing loss in the air gap of VCM. We present dual servo mechanism is effective mechanism for a force control in hi h precision, properties of designed VCM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.301-310
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• 2004

In this paper, a compact dual-mode filter structure without coupling gaps is proposed. The novel design is achieved by embedding a pair of equal crossed slots and spur-lines. Without coupling gaps between feed lines and patch resonator, the new filter can provide low insertion loss. It is found that this design has wide coupling range for dual-mode operation. It means that these characteristics of the proposed filter can reduce uncertainty in fabrication. By using two PIN diodes mounted inside a pair of spur-lines, the proposed structure works as a switchable filter. Also, it has a size reduction of about 34.7 %, compared with conventional dual-mode filters.