• 전기전자학회논문지
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• 제14권3호
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• pp.199-204
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• 2010

본 논문에서는 전력반도체의 내압을 유지하는데 있어서 가장 중요한 필드 링의 개선을 위해 새로운 구조의 필드 링을 제안하였다. 제안한 트렌치 필드 링은 기존의 일반 필드 링에 비해 10%이상 효율을 개선하였다. 트렌치 필드 링의 설계를 위해 5가지의 변수를 두고 최적화 시뮬레이션을 수행하였으며, 수행한 파라미터 결과를 가지고 마스크를 설계하여 제작을 진행하였다. 내압이 증가하면 증가할 수록 트렌치 필드링이 일반 필드 링보다 더 좋은 결과를 가져올 수 있었다. 이러한 결과는 앞으로 전력반도체 소자인 IGBT, Power MOS 및 MCT 소자의 설계에 충분히 활용할 수 있을 것으로 판단된다.

• 교육시설
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• 제15권2호
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• pp.4-15
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• 2008

The purpose of this study was to evaluate the characteristics of daylighting environment in classroom of an school building due to the external shading devices such as fixed louvers, light shelves and exterior venetian blinds. In this study, we have made a field research with regard to the facade design in classroom of an school building. And we have made a classification of external shading devices considering the design parameters. Finally, through RADIANCE simulation, we have calculated the spatial distribution of illuminance, uniformity ratio of illuminance and daylight factors. The results of this study will provide the building designer with the basic daylighting performance data at early design stages.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.15-18
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• 1996

The elemental segregation in the sputter-deposited AgInSbTe recording thin films was studied by means of Auger electron spectroscopy and ESCA for the specimens of as-deposited and as heat-treated conditions. Auger electron spectroscopy and ESCA revealed an extremely thin layer of elemental inhomogeneity, especially for the silver, even in as-deposited condition. The chemical analysis results obtained in this alloy system are discussed in terms of process parameters and target microstructure.

• Smart Structures and Systems
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• 제2권1호
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• pp.61-80
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• 2006

The concept of structural vibration control is to absorb vibration energy of the structure by introducing auxiliary devices. Various types of structural vibration control theories and devices have been recently developed and introduced into mechanical systems. One of such devices is damper employing controllable fluids such as ElectroRheological (ER) or MagnetoRheological (MR) fluids. MagnetoRheological (MR) materials are suspensions of fine magnetizable ferromagnetic particles in a non-magnetic medium exhibiting controllable rheological behaviour in the presence of an applied magnetic field. This paper presents the modelling of an MRfluid damper. The damper model is developed based on Newtonian shear flow and Bingham plastic shear flow models. The geometric parameters are varied to get the optimised damper characteristics. The numerical analysis is carried out to estimate the damping coefficient and damping force. The analytical results are compared with the experimental results. The results confirm that MR damper is one of the most promising new semi-active devices for structural vibration control.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.185-191
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• 2023

The Internet of Things (IoT) can be defined as the connection of devices, sensors, and actors via the Internet to a single network to provide services to end-users. Owing to the flexibility and simplicity of IoT devices, which impart convenience to end-users, the demand for these devices has increased significantly in the last decade. To make these systems more scalable, achieve a larger number of connected devices, and achieve greater economic success, it is vital to develop them by considering parameters such as security, cost, bandwidth, data rate, and power consumption. This study aims to improve energy efficiency and prolong the lifetime of IoT networks by proposing a new approach called the constrained application protocol CoAP45. This approach reduces the number of updates to the CoAP server using a centralized resource. The simulation results show that the proposed approach outperforms all existing protocols.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.29-34
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• 1993

In this paper, we used one-dimensional process simulator, SUPREM-II, and two-dimensional device simulator, MINIMOS 4.0 to extract optimal process parameter that can minimize degradation of device characteristics caused by process parameter variation in the case of short channel nMOSFET and pMOSFET device. From this simulation, we have derieved the relationship between process parameter and device characteristics. Here we have presented a method to extract process parameters from design trend curve(DTC) obtained by process and device simulations. We parameters to verify the validity of the DTC method. The experimental result of 0.8 $\mu\textrm{m}$ channel length devices that have been fabricated with optimal that reduces short channel effects, that is, good drain current-voltage characteristics, low body effects and threshold voltage of 1.0 V, high punchthrough and breakdown voltage of 12 V, low subthreshold swing(S.S) values of 105 mV/decade.

• ETRI Journal
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• 제26권4호
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• pp.307-314
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• 2004

The application of a discrete pseudomorphic high electron mobility transistor (p-HEMT) as a grounded switch allows for the development of low cost phase shifters and phase modulators operating in a Ku band. This fills the gap in the development of phase control devices comprising p-i-n diodes and microwave monolithic integrated circuits (MMICs). This paper describes a discrete p-HEMT characterization and modeling in switching mode as well as the development of a low-cost four-bit phase shifter and direct quadrature phase shift keying (QPSK) modulator. The developed devices operate in a Ku band with parameters comparable to commercially available MMIC counterparts. Both of them are CMOS compatible and have no power consumption. The parameters of the QPSK modulator are very close to the requirements of available standards for satellite earth stations.

• The Korean Journal of Ceramics
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• 제3권4호
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• pp.257-262
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• 1997

Aluminum nitride(AIN) thin films were deposited on SiO$_2$/Si substrates by reactive sputtering for the application of SAW devices. The major deposition parameters such as pressure, nitrogen fraction, rf power, substrate distance were changed to find out the optimal condition for c-axis oriented thin films on an amorphous substrate. The effects of deposition parameters on the crystal structure, residual stress, and growth morphology of thin films were characterized by XRD, SEM, and TEM. The FWHM of (002) rocking curve of the films deposited at the proper condition was lower than 2.2$^{\circ}$(C=0.93$^{\circ}$). Cross-sectional TEM showed that self-aligned structure was developed just after slightly random growth at the initial stage. The frequency characteristics of test device fabricated from AIN thin films confirmed their piezoelectric property and applicability for SAW devices.

• 전자공학회논문지A
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• 제31A권12호
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• pp.91-99
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• 1994

We used CMOS current mirror and differenial amplifier to find out how the degradation of each devices in circuit affect total circuit performance. The devices in circuit wer degraded by hot-carrier generated during circuit operation and total circuit performance were changed according to the change of each device parameters. To examine the circuit performance phenomena of current mirror, we analyzed three diffent kinds of current mirrors and made correlation model between circuit performance and stressed device parameters, and compare hot-carrier immunity of these circuits. Also we analyzed how the performance of differential amplifier degraded from the initial value after hot-carrier stress incircuit operations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.859-864
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• 1998

Compact and small size, reliable and failsafe operation and low cost featuring fault current limiter causing the designer to take a close look into the use of passive fault current limiter(FCL) for the protection of power semiconductor devices in power electronic systems. This paper has identified the main parameters responsible for the development of ideal passive magnetic current limiter. The effect of those parameters on the range of operation and the voltage-current characteristics of the magnetic current limiter has been studied using tableau approach. Desirable characteristics are discussed and the simulation results are presented.