• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2000년도 춘계학술발표논문집
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• pp.117-120
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• 2000

This paper describe VLSL design of crytographic processor which can execute triple DES and DES encryption algorithm. To satisfy flexible architecture and area-efficient structure, the processor has 1 unrolled loop structure without pipeline and can support four standard mode, such as ECB, CBC, CFB, and OFB modes. To reduce overhead of key computation , the key precomputation technique is used. Also to eliminate increase of processing time due to data input and output time, background I/O techniques is used which data input and output operation execute in parallel with encryption operation of cryptographic processor. The cryptographic processor is implemented using Altera EPF10K40RC208-4 devices and has peak performance of about 75 Mbps under 20 Mhz ECB DES mode and 25 Mbps uder 20 Mhz triple DES mode.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.8-16
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• 2013

This paper investigates the electrical characteristics of popular power converters such as a half-bridge rectifier, a full-bridge rectifier, a buck converter, and an inverter when the arc is occurred at the input and the output of each converter. In order to generate an artificial arc, the arc generator has been implemented according to the design guideline suggested in UL1699. After that, the trend of the input and output voltage variation and the switching stress of the devices are analyzed. From the analysis, it has been confirmed that the generated arc causes an uncertain operation to the power converters. To reduce the unexpected disturbance effect of the arc, the capacitor adjustment method has been proposed, and its superiority has been experimentally verified.

• 제어로봇시스템학회논문지
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• 제4권3호
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• pp.406-412
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• 1998

This paper describes a contact position detection method of a capacitive touch screen panel. The proposed method is composed of a circuited compensating algorithm generating an output signal having phase difference to an input signal associated with contact position, converts both input and output signals into digital waveform (5V logic), and calculates the phase difference. Finally, position information with the phase difference is obtained by using a low-cost microprocessor, which is convenient to compensate non-linearity error. The proposed method, that computes phase difference directly, has advantages in feasibility and cost because it minimizes the use of analog devices; rather, it utilizes, cost effective digital circuit. Analytical results are also given.

• Journal of Communications and Networks
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• 제9권2호
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• pp.141-149
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• 2007

Multiple-input multiple-output (MIMO) transmit pre-coding/beamforming can significantly improve system spectral efficiency. However, several obstacles prevent precoding from wide deployment in early wireless networks: The significant feedback overhead, performance degradation due to feedback delay, and the large storage requirement at the mobile devices. In this paper, we propose a precoding method that addresses these issues. In this approach, only 3 or 6 bits feedback is needed to select a precoding matrix from a codebook. There are fifteen codebooks, each corresponding to a unique combination of antenna configuration (up to 4 antennas) and codebook size. Small codebooks are prestored and large codebooks are efficiently computed from the prestored codebook, modified Hochwald method and Householder reflection. Finally, the feedback delay is compensated by channel prediction. The scheme is validated by simulations and we have observed significant gains comparing to space-time coding and antenna selection. This solution was adopted as a part of the IEEE 802.16e specification in 2005.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.535-539
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• 2008

Recently mobile devices can transmit mass data contained multi-media contents. According these flow, a demand for fast data transmission is being risen, so we acutely require remarkable technology that overcome mobile communication's poor environment and rise data transmission volume. Because it can be satisfied these needs, the OFDM(Orthogonal Frequency Division Multiplexing) that rise data transmission volume using efficient frequency, and MIMO(Multiple Input Multiple Output) that rise transmission confidence and data transmission volume using numbers of antenna is attended. Before design of MIMO-OFDM System we want to make an analysis for theory of its systems, and we want to design MIMO-OFDM simulator for verify an ability of modulation, data volume and numbers of antenna.

• 전기학회논문지P
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• 제61권2호
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• pp.59-66
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• 2012

Recently, the market of Electric Vehicle(EV) is increasing more and more than before. Thus a new heater for the EV is required. The PTC devices may be used the heater for the EV. In this paper, a simple DC-DC Converter is proposed as the PTC Heater for the EV. The proposed circuit was optimally desired to decrease the stress of the power devices and reduce the current ripples. To apply the result of the test in the laboratory to the actual EV system with the high DC voltage, ripple current, average current and output peak current are predicted by using the least-squares method. Finally, the proposed circuit is validated by various experiments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.379-380
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• 2006

As a result of growth sensor-enabled mobile devices such as PDA, cellular phone and other computing devices, in recent years, users can utilize the diverse digital contents everywhere and anytime. However, the interfaces of mobile applications are often unnatural due to limited resources and miniaturized input/output. Especially, users may feel this problem in some applications such as the mobile game. Therefore, Novel interaction forms have been developed in order to complement the poor user interface of the mobile device and to increase the interest for the mobile game. In this paper, we describe the demonstration of the gesture and posture input supported by an accelerometer. The application example we created are AM-Fishing game on the mobile device that employs the accelerometer as the main interaction modality. The demos show the usability for the gesture and posture interaction.

• Journal of electromagnetic engineering and science
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• 제8권1호
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• pp.17-22
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• 2008

It is presented that sampling rates for behavioral modeling of quasi-memory less nonlinear devices can be far less than the Nyquist rate of the input signal. Although it has been believed that the sampling rate of nonlinear device modeling should be at least the Nyquist rate of the output signal, this paper suggests that far less than the Nyquist rate of the input signal can be applied to the modeling of quasi-memoryless nonlinear devices, such as frequency multipliers. To verify, a QPSK signal at 820 MHz were applied to a frequency tripler, whereby the device can be utilized as an up-converting mixer into 2.46 GHz with the aid of digital predistortion. AM-AM, AM-PM and PM-PM can be successfully measured regardless of sampling rates.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.327-331
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• 2008

The problems of power factor and harmonics are occurred in converter system which used to SCRs and diodes as power semiconductor devices IGBT was solved that problem, maintain the input line current with sinusoidal wave current of input power source voltage. In this paper, three phase AC to DC boost converter that operates with unity power factor and sinusoidal input currents is presented. The current control of the converter is based on the space vector PWM strategy with fixed switching frequency and the input current tracks the reference current within one sampling time interval. Space vector PWM strategy for current control was materialized as a digital control method. By using this control strategy low ripples in the output voltage, low harmonics in the input current and fast dynamic responses are achieved with a small capacitance in the dc link.

• 전력전자학회논문지
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• 제6권5호
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• pp.400-409
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• 2001

대용량 승압형 응용을 위한 새로운 위상천이 병렬입력/직렬출력 듀얼 컨버터가 제안된 바 있다. 제안된 컨버터는 종래의 펄스 폭 변조(PWM) 방식의 병렬입력/직렬출력 듀얼 컨버터에 비해 낮은 스위치 전압 스트레스를 보여 저 손실의 소자를 사용할 수 있으므로 높은 효율을 보인다. 또한, 출력 캐패시터의 실효(RMS) 전류 스트레스가 낮고 입력 전류와 출력 전압의 맥동이 작으며, 제어 입력에 대한 출력 전압의 동역학(dynamics)이 빠른 장점이 있다. 본 논문에서는 제안된 컨버터의 정상상태 동작을 심도 있게 분석하고 그 수학적 모델 및 정상상태 해를 제시하며, 제안된 컨버터의 특징을 종래의 PWM 방식의 컨버터와의 비교를 통해 정량적으로 분석한다. 또한, 제안된 회로의 동작, 특성 및 유효성을 검증하기 위해 800W급 24-350Vdc 사양의 시작품으로부터의 실험 결과를 제시한다.