• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.441-448
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• 2008

The molecular docking system needs a large amount of computation and requires super-computing power. Since the experiment requires a large amount of time, the experiment is conducted in the distributed environment or in the grid environment. Recently, researches on using parallel GPU of far higher performance than that of CPU in scientific computing have been very actively conducted. CUDA is an open technique by which a parallel GPU programming is made possible. This study proposes the molecular docking system using CUDA. It also proposes algorithm that parallels energy-minimizing-computation. To verify such experiments, this study conducted a comparative analysis on the time required for experimenting molecular docking in general CPU and the time and performance of the parallel GPU-based molecular docking which is proposed in this study.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.349-354
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• 1998

The grid reference system (GRS) has been useful for identifying the geographical location of satellite images. In this study we derive a GRS for the KOMPSAT Electro-Optical Camera (EOC) images. The derivation substantially follows the way that SPOT defines for its GRS, but incorporates the KOMPSAT orbital characteristics. The KOMPSAT EOC GRS (KEGRS) is designed to be a (K,J) coordinate system. The K coordinate parallel to the KOMPSAT ground track denotes the relative longitudinal position and the J coordinate represents the relative latitudinal position. The numbering of K begins with the prime meridian of K=1 with K increasing eastward, and the numbering of J uses a fixed value of J=500 at all center points on the equator with J increasing northward. The lateral and vertical intervals of grids are determined to be 12.5 km about at the 38$^{\circ}$ latitude to allow some margins for the value-added processing. The above design factors are being implemented in a satellite programming module of the KOMPSAT Receiving and Processing System (KRPS) to facilitate the EOC data collection planning over the Korean peninsula.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1222-1223
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• 2007

This paper suggests a 6-pulse-shift converter with PWM current-source inverter based on buck-boost configuration to improve the efficiency and to reduce the switching frequency of inverter for photovoltaic generation system, the device can be operated as interface system between solar module system and power system grid without energy storage cell. the circuit has six current-source buck-boost converter which operate chopper part has one full bridge inverter which make a decision the polarity of AC output. Therefore, the proposed PWM power inverter has advantages such as the reduction of witching loss and realization of unity power factor operation. the theoretical backgrounds are discussed and the input-output characteristics for the implemented prototype inverter using TMS320F2812 are verified experimentally in this paper.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.287-289
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• 2009

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in computer applications to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. System operation simulation demonstrates that the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and changes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1994.10a
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• pp.79-90
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• 1994

The goal of this research is to get a measuring system for absorption characteristics of electromagnetic wave absorbers in ferrite type which are lat grid-type special type etc. It is however very difficult to measure the absorption characteristics as in low frequency as in 30 MHz, To solve the problem therefore we propose a standing wave method and a measurement method in time domain using parallel striplines construct the measuring system and measure the characteristics of ferrite microwave absorbers in grid type using the proposed measuring system.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1011-1020
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• 2004

A lot of work has been done to improve the I/O performance of such a system that store and manage a massive amount of data by distributing them across multiple disks and access them in parallel. Most of the previous work has focused on an efficient mapping from a grid ceil, which is determined bY the interval number of each dimension, to a disk number on the assumption that each dimension is split into disjoint intervals such that entire data space is GRID-like partitioned. However, they have ignored the effects of a GRID partitioning scheme on declustering performance. In this paper, we enhance the performance of mapping function based declustering algorithms by applying a good GRID par-titioning method. For this, we propose an estimation model to count the number of grid cells intersected by a range query and apply a GRID partitioning scheme which minimizes query result size among the possible schemes. While it is common to do binary partition for high-dimensional data, we choose less number of dimensions than needed for binary partition and split several times along that dimensions so that we can reduce the number of grid cells touched by a query. Several experimental results show that the proposed estimation model gives accuracy within 0.5% error ratio regardless of query size and dimension. We can also improve the performance of declustering algorithm based on mapping function, called Kronecker Sequence, which has been known to be the best among the mapping functions for high-dimensional data, up to 23 times by applying an efficient GRID partitioning scheme.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1662-1664
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• 2003

An electron gun system for a nanosecond pulse linac has been built and tested. The gun grid is driven with a grid pulser, which consists of an avalanche transistor pulser and parallel triode amplifier. The amplifier is installed in an end hole of the electron gun and provided for power amplification and polarity change of the output pulses of the avalanche transistor pulser. An output pulse of 200 V and 2 ns FWHM was obtained by using the grid pulser of can type transistors. Measurements with a test bench show that the electron gun can deliver 2ns pulse with with currents larger than 3A.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.797-802
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• 2011

RFID is recognized to technically occupy important position in ubiquitous computing environment and expected to create new markets in a variety of fields from now on. In order to generalize RFID system, it is required to solve the problem of privacy invasion and expedite lots of tags We suggest efficient RFID Tag Identification to identify tags quickly on the satisfaction with 3 security requirements of privacy protection in this paper. This methods are transferred to Grid environment through parallel analysis of Hash-Chain, and we measure performance of each nodes under the Grid environment. Then, We'll suggest SP-Division Algorithm to identify tags with each nodes and implement it in a Grid environment.

• Journal of Power Electronics
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• v.18 no.1
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• pp.185-194
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• 2018

Interaction among multiple grid-connected inverters has a negative impact on the stable operations and power quality of a power grid. The interrelated influences of inverter inductor-capacitor-inductor filters constitute a high-order power network, and consequently, excite complex resonances at various frequencies. This study first establishes a micro-grid admittance matrix, in which inverters use deadbeat control. Multiple resonances can then be evaluated via modal analysis. For the active damping method applied to deadbeat control, the sampling frequency and the stable domain of the virtual damping ratio are also presented by analyzing system stability in the discrete domain. Simulation and experimental results confirm the efficiency of modal analysis and stable domain calculation in multi-inverter grid-connected systems.

• The KIPS Transactions:PartA
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• v.16A no.1
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• pp.9-16
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• 2009

Because Grid system consists of heterogenous computing resources, which are distributed on a wide scale, it is impossible to efficiently execute applications with scheduling algorithms of a conventional parallel system that, in contrast, aim at homogeneous and controllable resources. To suggest an algorithm that can fully reflect the characteristics of a grid system, our research is focused on examining the type of information used in current scheduling algorithms and consequently, deriving factors that could develop algorithms further. The results from the analysis of these algorithms not only show that static information of resources such as capacity or the number of processors can facilitate the scheduling algorithms but also verified a decrease in efficiency in case of utilizing real time load information of resources due to the intrinsic characteristics of a grid system relatively long computing time, and the need for the means to evade unfeasible resources or ones with slow processing time. In this paper, we propose a new algorithm, which is revised to reflect static information in the logic of WQR(Workqueue Replication) algorithms and show that it provides better performance than the one used in the existing method through simulation.