• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.4
• /
• pp.96-103
• /
• 2005

We designed the compound CVT(Continuously Variable Transmissions) by combining power circulation mode and power split mode, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU(Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments for efficiency, speed ratio, power flow, and power transmission ratio. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.3184-3186
• /
• 1999

In this paper, a new structure of fully differential delay cell VCO using quadrature phase for low phase noise and high speed operation is suggested. It is realized by inserting voltage clamp circuit into input pairs of delay cells that include three-control current source having high output impedance. In this reason. this newly designed delay cell for VCO has the low power supply sensitivity so that the phase noise can be reduced. The whole characteristics of VCO were simulated by using HSPICE and SABER. Simulation results show that the phase noise of new VCO is quite small compared with conventional fully differential delay cell VCO and ring oscillator type VCO. It is also very beneficial to low power supply design because of wide tuning range.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.670-673
• /
• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H II differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.29 no.6
• /
• pp.1259-1270
• /
• 2019

The upper bound of differential characteristic probability is mainly used to determine the number of rounds when constructing a block cipher. As the number of rounds affects the performance of block cipher, it is critical to evaluate the tight upper bound in the constructing process. In order to calculate the upper bound of differential characteristic probability, the previous searching methods for minimum number of active S-boxes constructed constraint equations for non-linear operations and linear operations, independently. However, in the case of BOGI design strategy, where linear operation is dependent on non-linear operation, the previous methods may present the less tight upper bound. In this paper, we exploit the properties of BOGI strategy to propose a new method to evaluate a tighter upper bound of differential characteristic probability than previous ones. Additionally, we mathematically proved the validity of our method. Our proposed method was applied to GIFT-64 and GIFT-128, which are based on BOGI strategy, and the upper bounds of differential characteristic probability were derived until 9 round. Previously, the upper bounds of differential characteristic probability for 7-round GIFT-64 and 9-round GIFT-128 were 2^-18.395 and 2^-26.885, respectively, while we show that the upper bounds of differential characteristic probability are more tight as 2^-19.81 and 2^-28.3, respectively.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.149-152
• /
• 2004

A new joint source channel coding reduces both input-width and average current consumption to transmit image data to LCD source drivers. As a source coding, it is based on entropy coding of differential pulse code modulation scheme, especially using median edge detector of image predictor. As a channel coding, it is not a simple pulse amplitude modulation, but linked by source entropy to reduce average amplitude. Simulation results show 1/4 width is achievable by 16-valued transmission with keeping conventional current consumption (0.36 to 1.3).

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.46-52
• /
• 1991

A new signal process circuit using two ISFETs as the input devices of the MOS differential amplifier stage for an ISFET biosensor has been developed. One chip integration of the newly developed signal process circuit, ISFETs and a Pt quasi-reference electrode has been carried out according to modified LOCOS p-well CMOS process. The fabricated chip showed gains of 0.8 and 1.6, good liniarity in the input-output relationship and very small power dissipation, 4mW. The chip was applied to realize a urea sensor by forming an immobilized urease membrane, using lift-off technique. on the gate of an ISFET. The urea sensor chip showed stable responses in a wide range of urea concentrations.

• Journal of Power System Engineering
• /
• v.4 no.3
• /
• pp.62-71
• /
• 2000

A mathematical modeling for a magnetic levitation system is proposed using the Taylor series expansion of differential function for obtaining linearity. It is confirmed that this kind of linear approximation method can be used to the modeling of a magnetic levitation system. The two-degree-of-freedom optimal servo system for a constant reference signal is proposed using the LQ optimization technique. An additional state feedback is introduced at the output of the integrator to cancel the integral action for reference signal if there is no modeling error of the plant and no disturbance input to the plant. When the modeling error or the disturbance input exists, the integral effect appears. The system has a free parameter which can b used to tune the effect of the integral compensation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1580-1584
• /
• 2009

We have theoretically analyzed the monolithic integration of vertical cavity lasers with depleted optical thyristor (VCL-DOT) structure and experimentally demonstrated optical logic gates such as AND-gate, OR-gate, and INVERTER implemented by VCL-DOT for an optical programmable gate array. The optical AND and OR gates have been realized by changing a input bias of the single VCL-DOTs and all kinds of optical logic functions are also implemented by adjusting an intensity of the reference input beams into the differential VCL-DOTs. To achieve the high sensitivity, high slope efficiency and low threshold current, a small active region of lasing part and a wide detecting area are simultaneously designed by using a selective oxidation process. The fabricated devices clearly show nonlinear s-shaped current-voltage characteristics and lasing characteristics of a low threshold current with 0.65 mA and output spectrum at 854 nm.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.12
• /
• pp.40-48
• /
• 1998

An offset compensation scheme for rail-to-rail CMOS op-amps with complementary input stages is presented. Two auxiliary amplifiers are used to compensate for the offsets of NMOS and PMOS differential input stages, and ping-pong control is employed for continuous-time operation. A 3V offset-compensated rail-to-rail CMOS op-amp has been designed and fabricated using a 0.8$\mu\textrm{m}$ single-poly, double-metal CMOS process. Measurement results show that offsets are reduced about 20 times by this scheme.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.145-148
• /
• 1999

It is known that Volterra kernel models can represent a wide variety of nonlinear chemical processes. Also, it is necessary for Volterra model identification to excite the process to be identified with a signal having wide range of frequency spectrum and high enough amplitude of input signals. Kashiwagi[4 ∼ 7] has recently shown a method for measuring Volterra kernels up to third order using pseudorandom M-sequence signals. However, in practice, since it is not always possible to apply such input sequences to the actual chemical plants. Even when we can apply such a pseudorandom signal to the process, it takes much time to obtain higher order Volterra kernels. Considering these problems, the authors propose here a new method for practical identification of Volterra kernels by use of approximate open differential equation (ODE) model and simple plant test. Simulation results are shown for verifying the usefulness of our method of identification of nonlinear chemical processes.