• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1058-1062
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• 2000

We investigated resistive superconducting fault current limites (SFCLs) fabricated using YBCO thin films on 2-inch diameter sapphire substrates. Nearly identical SFCL units were prepared and tested. The units were connected in series and parallel to increase the current and voltage ratings. A serial connection of the units showed significantly unbalanced power dissipation between the units. This imbalance was removed by introducing a shunt resistor to the firstly quenched unit. Parallel connection of the units increased the current rating. An SFCL module of 4 units in parallel, each of which has minimum quench current rating. An SFCL module of 4 units in parallel, each of which has minimum quench current 25 A$\_$peak/, was produced and successfully tested at a 220 V$\_$rms/circuit. From the resistance increase, we estimated that the film temperature increased to 200 K in 5 msec, and 300 K in 120 msec. Successive quenches revealed that this system is stable without degradation in the current limiting capability under such thermal shocks as quenches at 220 V$\_$rms/.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1021-1024
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• 1999

In this paper, we propose a modified feedback neural network structure for adaptive control of robot manipulators. The proposed structure is that all of network output feedback into hidden units and output units. Learning algorithm is standard back-propagation algorithm. The simulation showed the effectiveness of using the new neural network structure in the adaptive control of robot manipulators.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.715-718
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• 2005

Mobile devices is getting to include more functions according to the demand of digital convergence. Applications based on 3D graphic calculation such as 3D games and navigation are one of the functions. 3D graphic calculation requires heavy calculation. Therefore, we need dedicated 3D graphic hardware unit with high performance. 3D graphic calculation needs a lot of complicated floating-point arithmetic operation. However, most of current mobile 3D graphics processors do not have efficient architecture for mobile devices because they are based on those for conventional computer systems. In this paper, we propose arithmetic units for special functions of lighting operation of 3D graphics. Transcendental arithmetic units are designed using approximation of logarithm function. Special function units for lighting operation such as reciprocal, square root, reciprocal of square root, and power can be obtained. The proposed arithmetic unit has lower error rate and smaller silicon area than conventional arithmetic architecture.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.111-118
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• 2017

The increased diversity of different types of energy sources requires moving towards smart distribution networks. This paper proposes a probabilistic DG (distributed generation) units planning model to determine technology type, capacity and location of DG units while simultaneously allocating ESS (energy storage systems) based on pre-determined capacities. This problem is studied in a wind integrated power system considering loads, prices and wind power generation uncertainties. A suitable method for DG unit planning will reduce costs and improve reliability concerns. Objective function is a cost function that minimizes DG investment and operational cost, purchased energy costs from upstream networks, the defined cost to reliability index, energy losses and the investment and degradation costs of ESS. Electrical load is a time variable and the model simulates a typical radial network successfully. The proposed model was solved using the DICOPT solver under GAMS optimization software.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.178.2-178
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• 2001

Today, many electronic devices and ECUs (Electronic Control Units) are used in the automotive body control systems. It becomes more common that these devices exchange data with others through an in-vehicle network. Automobile manufacturers concentrate their efforts on development of body control systems based on networks in order to save cost and to increase flexibility and safety. OSEK/VDX has been founded as a joint project in German and French automotive industry aiming at an industry standard for an open-ended architecture for distributed control units in vehicles OSEK/VDX consists of Communication (specification of data exchange within and between control units), Network Management specification of Configuration determination and monitoring and Operating System (specification of realtime executive for ECU software ...

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.417-422
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• 1998

he Reactor Coolant Gas Vent System(RCGVS) design for Ulchin Nuclear Power Plant Units 3&4(UCN 3&4) has been improved from the Yonggwang Nuclear Power Plant Units 3&4(YGN 3&4) based on the evaluation results for depressurization capability tests performed at YGN 3&4. There has been a series of plant safety analyses for Natural Circulation Cooldown(NCC) event and thermo-dynamic analyses with RELAP5 code for the steam blowdown Phenomena in order to optimize the orifice size of UCN 3&4 RCGVS. Baesd on these analyses results, the RCGVS orifice size for UCN 3&4 has been reduced to 9/32 inch from the l1/32 inch for YGN 3&4. The depressurization capability tests, which were performed at UCN 3 in order to verify the FSAR NCC analysis results, show that the RCGVS depressurization rates are being within the acceptable ranges. Therefore, it is concluded that the orificed flow path of UCN 3&4 RCGVS is adequately designed, and can provide the safety-grade depressurization capability required for a safe plant operation.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.711-714
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• 2005

We propose floating point arithmetic units for geometry operation of mobile 3D graphic processor. The proposed arithmetic units conform to the single precision format of IEEE standard 754-1985 that is a standard of floating point arithmetic. The rounding algorithm applies the nearest toward zero form. The proposed adder/subtraction unit and multiplier have one clock cycle latency, and the inversion unit has three clock cycle latency. We estimate the required numbers of arithmetic operation for Viewing transformation. The first stage of geometry operation is composed with translation, rotation and scaling operation. The translation operation requires three addition and the rotation operation needs three addition and six multiplication. The scaling operation requires three multiplication. The viewing transformation is performed in 15 clock cycles. If the adder and the multiplier have their own in/out ports, the viewing transformation can be done in 9 clock cycles. The error margin of proposed arithmetic units is smaller than $10^{-5}$ that is the request in the OpenGL standard. The proposed arithmetic units carry out operations in 100MHz clock frequency.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.49-54
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• 2013

Japan and South Korea since 2004 until now for the broadcast channel interference, by measuring the ongoing conflict are expected to prepare for the future, but Korea's preparation are not enough. In this study, it is pointed that cause of the interference through channel environmental analysis, and effective application of propagation prediction model was carried out between neighboring countries. Between Korea and Japan, radio duct occurs on hold due to changes in the refractive gradient, and comfirmed occurrence of broadcasts interference. The results are presented that 1% time variable, -91.80 [N-units/km], 10% time variable, -43.92 [N-units/km], 50% time variable, -586.19 [N-units/km], for effective refractive gradient. Proposed refractive gradient could contribute to actual radio propagation prediction.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1181-1188
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• 2017

The unit and fundamental units of number fields are important to number field sieves testing primality of more than 400 digits integers and number field seive factoring the number in RSA cryptosystem, and multiplication of ideals and counting class number of the number field in imaginary quadratic cryptosystem. To minimize the time and space in H/W implementation of cryptosystems using fundamental units, in this paper, we introduce the Dirichlet's unit Theorem and propose our process of generating the fundamental units of the number field. And then we present the algorithm generating our fundamental units of the number field to minimize the time and space in H/W implementation and implementation results using the algorithm over the number field.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.524-531
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• 2010

The automobile networks consist of the communication bus systems which become independent and heterogeneous each other. Most often, the CAN buses are implemented in a car in order to connect all the electronic control units in various ways. Thus, some gateways are necessary for exchanging the useful information between electronic control units on the buses. The automobile body networks group is divided into two kinds on a large scale, namely the low-speed bus and the high-speed bus. To interchange messages between the two, a CAN signal gateway is designed and implemented in a miniature scale. A network analyzer (called "Vehicle spy") and an oscilloscope monitor network situation to confirm the due operation of CAN signal gateway. The efficiency of the designed gateway is evaluated. The more message thread increased, the more efficiency decreased.