• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1087-1095
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• 1990

A finite element method is used for analyzing the resonance characteristics of circular wind tunnel. Two-dimensional circular wind tunnel with one and three slots is considered. The wind tunnel resonance characteristics are affected by the number and position of the slots of the wind tunnel. The resonant frequencies for the vertical vibration mode are higher than those for the horizontal vibration mode. The resonance frequencies increase as the open area ratio increases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.6
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• pp.629-635
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• 1997

The theory of characteristic modes for coaxial waveguide with periodic axial slots is used to derive the weighted eigenvalue equation for calculating the characteristic values and the characteristic currents. Once the characteristic values and the characteristic currents are obtained, the important quantities such as the equivalent magnetic current, radiation patterns, and RCS are determined. Numerical results of the equivalent magnetic currents, radiation patterns, and RCS are compared with those obtained by use of the method of moments. A fairly good correspondence is observed between them.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.117-119
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• 2005

This parer presents the application of response surface methodology (RSM) to design optimization for two types of synchronous reluctance motors (SynRMs) one has 12 slots with distributed winding, and the other has 6 slots with concentrated winding, to improve the ratio between torque ripple and average torque. The usefulness of RSM in optimization problem of SynRM is verified as compared with the results of finite element analysis. In the end, the optimized two SynRMs are compared with SynRM currently used in air-conditioning compressor in connection with torque performance and loss.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.71-72
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• 2015

본 논문에서는 CPW(Coplanar waveguide) 급전되는 평면 루프 슬롯을 2.45 GHz 대역 Wi-Fi용으로 소형화 설계하는 방법에 대해 연구하였다. 제안된 구조는 직사각형 형태의 CPW 급전 루프 슬롯 안테나를 기본형으로 하여 내부 패치에 슬롯을 좌우 대칭으로 여러 개 수직 방향으로 배치한 안테나이며, FR4 기판의 한 면에 인쇄된다. 여러 가지 파라미터 값들이 안테나의 특성에 미치는 영향을 관찰하고 기존 루프 슬롯 안테나를 소형화하는 방법에 대해 연구하였다. FR4 기판에 $80mm{\times}50mm$ 크기로 2.45 GHz 대역용으로 설계된 안테나의 특성을 시뮬레이션을 통해 분석하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.746-751
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• 2009

We propose a dynamic time allocation method in cooperative multiplexing with partial relaying system. This method uses a linear programming and considers protocol that is based on relaying of partial information bits followed by cooperative multiplexing. In this protocol, regardless of the location of relay, the allocation time for each transmission time slots are constant. Using a dynamic time allocation method with considering the location of relay, we can find optimal transmission time slots, and show that the system capacity is optimized.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2016-2021
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• 2009

In this paper, a dual-band antenna aimed for a mobile communication repeater was designed and measured. The operating frequency ranges are GSM(870${\sim}$960 MHz) and WCDMA(1920${\sim}$2170 MHz) bands. Experimental and numerical studies are performed for various design variables such as slot lengths. Using two meandering slots in the ground plane, we can obtain two higher resonant frequencies significantly with broader bandwidths. The measured maximum gain of antenna is 2 dBi in the GSM band and 2.45 dBi in the WCDMA band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.368-373
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• 2006

In this paper, a CPW fed rectangular slot antenna loaded with two slots for dual band operation is presented. This antenna operates at about 2.1GHz and 3.3GHz with the broad bandwidth at these frequencies. a CPW inset structure is used to match the antenna at the two seperated frequencies. Some prototypes of the proposed dual frequency antenna have been implemented. Experimental results are presented and discussed.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.29-34
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• 2007

This paper proposes a MAC protocol for real-time VBR (rt-VBR) services in wireless ATM networks. The proposed protocol is characterized by a contention-based mechanism of the reservation request, a contention-free polling scheme for transferring the dynamic parameters, and a priority scheme of the slot allocation. The design objective of the proposed protocol is to guarantee the real-time constraint of rt-VBR traffic. The scheduling algorithm uses a priority scheme based on the maximum cell transfer delay parameter. The wireless terminal establishes an rt-VBR connection to the base station with a contention-based scheme. The base station scheduler allocates a dynamic parameter minislot to the wireless terminal for transferring the residual lifetime and the number of requesting slots as the dynamic parameters. Based on the received dynamic parameters, the scheduler allocates the uplink slots to the wireless terminal with the most stringent delay requirement. The simulation results show that the proposed protocol can guarantee the delay constraint of rt-VBR services along with its cell loss rate significantly reduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.923-926
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• 2017

In this study, a novel wideband conformal thin antenna is presented for endoscopic capsule application at the 915 MHz Industrial, Scientific and Medical (ISM) band. The thickness of the antenna is only 0.2 mm which can be wrapped inside a capsule's inner wall. By cutting meandered slots on patch, open end slots on ground and utilizing long arm, the proposed antenna can obtain significant size reduction. The net volume of the proposed antenna including substrate and superstrate is only $37.4mm^3$ ($187mm^2$ surface area). This conformal antenna has shown good performance through simulation and measurement with maximum gain of -23 dBi and wide bandwidth from 137 MHz - 205 MHz depending on different environment. In addition, the effect of internal materials specially metallic battery is discussed briefly.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.41-49
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• 2015

In this paper, we studied an optimal design and efficiency improvement of the BLCD motor used in home electronic appliance. The number of stator slots is chosen depending on the rotor poles, phase number, and the winding configuration. In general, a fractional slots/pole design is preferred to minimize cogging torque. To reduce the winding resistance, we reduced the coil length and we improved the coil space factor. We proposed three types of stator slot shape design for the optimal BLDC motor design. One of them, U-type slot shape is a best optimal design, it proved by the simulated and tested. Optimal design of essential parameters aiming at high winding factor are presented to create for a high-quality system implementation. Design analysis is verified by testing and building a prototype motor.