• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.208-212
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• 2003

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the conceptual design results of the multi-mode pulsed Doppler radar system testbed model for helicopter. Due to the inherent flight nature of the hovering vehicle which is flying in low-altitude and low speed, as well as rapid maneuvering, the moving clutters from the platform should be suppressed by using a special MTD (Moving Target Detector) processing. For the multi-mode radar system model design, the flight parameters of the moving helicopter platform were assumed: altitude of 3 Km, average cruising velocity of 150knots. The multi-mode operation capability was applied such as short-range, medium-range, and long-range depending on the mission of the vehicle. The nominal detection ranges is 30 Km for the testbed experimental model, but can be expanded up to 75 Km for the long range weather mode. The detection probability of each mode is also compared in terms of the signal-to noise ratio of each mode, and the designed radar system specifications ate provided as a design results.

• 한국간호교육학회지
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• 제16권1호
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• pp.51-60
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• 2010

Purpose: The purpose of this study was to compare the effects of nursing simulations between multi-mode simulation and $SimMan^{(R)}$ simulation on nursing students' nursing competency, satisfaction, and simulation participation experience in nursing care for patients with dyspnea. Method: Subjects were 107 junior nursing students in R College of Nursing in Seoul from June to November in 2009. Students were allocated to either a Multi-mode simulation group or a $SimMan^{(R)}$ simulation group. The multi-mode simulation consisted of standardized patients combined with Vital Sim, comparing the $SimMan^{(R)}$ group. Result: The Multi-mode simulation group reported higher levels of nursing competency (p=.017) but lower communication skills (p<.001) compared to the $SimMan^{(R)}$ simulation group. There were no meaningful differences in satisfaction of simulation education between the two groups. The $SimMan^{(R)}$ simulation group received a substantial health assessment and the Multi-mode simulation group experienced reality in caring for standardized patients. Conclusion: The findings of this study demonstrated that Multi-mode simulation has similar educational effects like $SimMan^{(R)}$ simulation and suggest that nurse educators should match simulation fidelity with educational goals for effective education.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.615-616
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• 2006

Nowadays, the need of multi-mode/multi-band transceiver is rapidly increasing, so we design a direct conversion RF front-end for multi-mode/multi-band receiver that support WCDMA/CDMA2000/WIBRO standard. It consists of variable gain reconfigurable LNA and single input double balanced Mixer and complementary differential LC Oscillator. The circuit is implemented in 0.18 um RF CMOS technology and is suitable for low-cost mode/multi-band.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.42-46
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• 2019

In this paper, we introduce the novel idea to improve parallel test efficiency of semiconductor test. The idea includes the test interface card consisting of NoC structure able to transmitting test data regardless of ATE speed. We called the scheme "Multi-Clock" mode. In the proposed mode, because NoC can spread over the test data in various rates, many semiconductors are tested in the same time. We confirm the proposed idea will be promising through a FPGA board test and it is important to find a saturation point of the Multi-Clock mode due to the number of test chips and ATE channels.

• Smart Structures and Systems
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• 제23권6호
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• pp.565-577
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• 2019

One of the most effective countermeasures for mitigating cable vibration is to install mechanical dampers near the anchorage of the cable. Most of the dampers used in the field are so-called passive dampers where their parameters cannot be changed once designed. The parameters of passive dampers are usually determined based on the optimal damper force obtained from the universal design curve for linear dampers, which will provide a maximum additional damping for the cable. As the optimal damper force is chosen based on a predetermined principal vibration mode, passive dampers will be most effective if cable undergoes single-mode vibration where the vibration mode is the same as the principal mode used in the design. However, in the actual engineering practice, multi-mode vibrations are often observed for cables. Therefore, it is desirable to have dampers that can suppress different modes of cable vibrations simultaneously. In this paper, MR dampers are proposed for controlling multi-mode cable vibrations, because of its ability to change parameters and its adaptability of active control without inquiring large power resources. Although the highly nonlinear feature of the MR material leads to a relatively complex representation of its mathematical model, effective control strategies can still be derived for suppressing multi-mode cable vibrations based on nonlinear modelling, as proposed in this paper. Firstly, the nonlinear Bouc-wen model is employed to accurately portray the salient characteristics of the MR damper. Then, the desired optimal damper force is determined from the universal design curve of friction dampers. Finally, the input voltage (current) of MR damper corresponding to the desired optimal damper force is calculated from the nonlinear Bouc-wen model of the damper using a piecewise linear interpolation scheme. Numerical simulations are carried out to validate the effectiveness of the proposed control algorithm for mitigating multi-mode cable vibrations induced by different external excitations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.874-880
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• 2003

Many mechanical systems are over-constrained if only rigid bodies are used to model the system. One example of such system is a satellite system with solar panels. To avoid this over-constrained problem, solar panels can be modeled as flexible bodies. The CMS(Component Mode Synthesis) method is widely used to analyze the flexible multi-body system because it can considerably approximate the deformation of the flexible bodies using small number of well-selected mode. However, it is very difficult to decide the boundary condition and the selection of modes. In this paper, the methods for mode synthesis and setting the boundary condition are presented to analyze the flexible multi-body system with over-constraints. Finally, the reliability of proposed method is verified by solar panel's deployment test.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.167-173
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• 2014

A novel multi-oxide layer structure for vertical cavity surface emitting laser (VCSEL) structures is proposed to achieve higher single mode output power. The structure has four oxide layers with different aperture sizes and thicknesses. The oxide layer thicknesses are optimized simultaneously to reach the highest single mode output power. A heuristic method is proposed for plotting the influence of these variable changes on the operation of optical output power. A comprehensive optical-electrical thermal-gain self-consistent VCSEL model is used to simulate the continuous-wave operation of the multi-layer oxide VCSELs. A comparison between optimized VCSELs with different structures is presented. The results show that by using multi-oxide layers with different thicknesses, higher single-mode optical output power could be achieved in comparison with multi-oxide layer structures with the same thicknesses.

• 한국정보전자통신기술학회논문지
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• 제9권6호
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• pp.578-583
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• 2016

본 논문에서는 이중루프 구조를 갖는 다중모드 무선전력전송 시스템을 제안하였다. 본 논문에서 제안한 다중모드 무선전력전송 시스템은 두 개의 서로 다른 주파수 6.78 MHz 자기공진 무선전력전송 모드와 13.56 MHz NFC 모드로 동작하는 외부 루프 모듈과 두 개의 서로 다른 주파수에서 동작하는 자기유도 표준인 WPC 모드와 PMA 모드로 동작하는 외부 루프와 연결된 내부 루프 모듈로 구성된다. 실제 상용 스마트폰 배터리 커버에 장착하기 위해 페라이트 시트를 포함한 $45{\times}90{\times}0.35mm3$ 크기에 맞춰 설계 및 최적화 되었다. 제안된 다중모드 무선전력전송 시스템은 기존의 자기유도방식 표준에 해당하는 WPC와 PMA를 지원할 뿐만 아니라 6.78 MHz 및 13.56 MHz에서 20 dB 이상의 반사손실 특성을 나타내었고 6.78 MHz 자기공진 무선충전 환경에서는 공진코일 간 70% 이상의 효율 특성을 갖는다.

• Journal of Power Electronics
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• 제14권5호
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• pp.1069-1078
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• 2014

This study presents the design and implementation of a web-based remote laboratory for a multi-mode single-leg power converter, which is a topic in advanced power electronics course. The proposed laboratory includes an experimental test rig with a multi-mode single-leg power converter and its driver circuits, a measurement board, a control platform, and a LabVIEW-based user interface program that is operated in the server computer. Given that the proposed web-based remote laboratory is based on client/server architecture, the experimental test rig can be controlled by a client computer with Internet connection and a standard web browser. Although the multi-mode single-leg power converter can work at four different modes (main boost, buck-boost, boost-boost, and battery boost modes), only the buck-boost mode is used in the experiment because of page limit. Users can choose the control structure, control parameters, and reference values, as well as obtain graphical results from the user interface software. Consequently, the feedbacks received from students who conducted remote laboratory studies indicate that the proposed laboratory is a useful tool for both remote and traditional education.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.147-156
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• 2007

This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigate the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a energy loss ratio of cable potential, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, it is assumed to exist three kinds of multi-mode patterns such as ambient vibration, support excitation and rain-win induced vibration. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5. In case of support excitation or rain-wind induced vibration is between 0.5 and 1.0. In this study, the effects of cable sag and inclination angle are included in the asymptotic design equation of damped cable structures.