• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.401-408
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• 1997

Human gets almist all of his knoweledge from the recognition and the accumulation of input patterns,image or sound,the he gets theough his eyes and through his ears.Among these means,his chracter recognition,an ability that allows him to recognize characters and understand their meanings through visual information, is now applied to a pattern recognition system using neural network in computer. Recurrent neural network is one of those models that reuse the output value in neural network learning.Recently many studies try to apply this recurrent neural network to the classification of static patterns like off-line handwritten characters. But most of their efforts are not so drrdtive until now.This stusy suggests a new type of recurrent neural network for an deedctive classification of the static patterns such as off-line handwritten chracters.Using the new J-E(Jordan-Elman)neural network model that enlarges and combines Jordan Model and Elman Model,this new type is better than those of before in recobnizing the static patterms such as figures and handwritten-characters.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.181-192
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• 2011

A mobile phone is becoming no longer a voice communication tool due to smartphones and mobile internet. Also, it now becomes a total entertainment device on which we can play game and get services by variety applications through the Web. As smartphones are getting more popular, their usages are also increased, which makes the interest of advertising industry in mobile advertisement increased but it is bound to be limited by the size of the screen. In this paper, we suggest an augmented reality logo system based on Android platform to maximize the effect of logo advertisement. After developing software and mounting it on a real smartphone, its performances are analyzed in various ways. The results show the possibility of its application to real world but it's not enough to provide real time service because of the low performance of hardware.

• Plant Journal
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• v.8 no.4
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• pp.34-39
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• 2012

This study presents how low quality coal combustion affects the desulfurizer draft system by correlating of draft loss in a coal-fired thermal power plant and predicts the stall occurrence time of a booster fan. In case of low quality coal, a lot of coal is needed to generate equivalent output power, thereby the rating of increasing draft loss was faster than designed amount of coal. We surely confirmed that draft loss affects the specific energy of a booster fan strongly. On this basis, it is possible to predict the occurring time of stall for a booster fan from current operation specific energy to stall limit specific energy. This study suggests increasing speed of draft loss in each caloric value and the impact of specific energy at a booster fan, it expects to help safe operating in a thermal power plant.

• Spatial Information Research
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• v.17 no.3
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• pp.371-379
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• 2009

Recently, GPU (Graphics Processing Unit) has been improved rapidly on the need of speed for gaming. As a result, GPU contains multiple ALU (Arithmetic Logic Unit) for parallel processing of a lot of graphics data, such as transform, ray tracing, etc. Therefore, this paper proposed a technique for parallel processing of spatial data using GPU. Spatial data consists of multiple coordinates, and each coordinate contains value of x and y axis. To display spatial data graphics operations have to be processed to large amount of coordinates. Because the graphics operation is identical and coordinates are multiple data, SIMD (Single Instruction Multiple Data) parallel processing of GPU can be used for processing of spatial data to improve performance. This paper implemented SIMD parallel processing of spatial data using two kinds of SDK (Software Development Kit). CUDA and ATI Stream are used for NVIDIA and ATI GPU respectively. Experiments that measure time of calculation for graphics operations are carried out to observe enhancement of performance. Experimental result is reported that proposed method can enhance performance up to 1,162% for graphics operations. The proposed method that uses parallel processing with GPU for spatial data can be generally used to enhance performance for applications which deal with large amount of spatial data.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.54-58
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• 2007

Development of high performance LTPS TFTs contributed to open up new SOP technology with various digital circuits integrated in display panels. This work introduces the current mode logic(CML) gate design method with which one can replace slow CMOS logic gates. The CML inverter exhibited small logic swing, fast response with high power consumption. But the power consumption became compatible with CMOS gates at higher clock speed. Due to small current values in CML, layout area is smaller than the CMOS counterpart even though CML uses larger number of devices. CML exhibited higher noise immunity thanks to its non-inverting and inverting outputs. Multi-input NAND/AND and NOR/OR gates were implemented by the same circuit architecture with different input confirugation. Same holds for MUX and XNOR/XOR CML gates. We concluded that the CML gates can be designed with few simple circuits and they can improve power consumption, chip area, and speed of operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6A
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• pp.425-432
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• 2003

In this paper, we designed a multi-carrier digital transmitter for CDMA base-station using a direct conversion scheme and verified the performance through circuit simulations. We examined a new technology required to design a multi-carrier transmitter, then designed and simulated a multi-carrier digital transmitter. ADS (Advanced Design System), RF simulation S/W of Agilent Technologies, was used for designing and simulating the multi-carrier digital transmitter. First, we simulated a digital block and an analog block separately, then performed a co-simulation for entire system. From the results, the final analog outputs of the designed multi-carrier digital transmitter met the spectrum mask characteristics of IS-97 & 3G TS 25.104 standard requirements. It means that proposed scheme could be applied to implement a multi-carrier digital transmitter for CDMA base-station. Therefore, proposed multi-carrier digital transmitter using a direct conversion scheme can accomplish cost-reduction and improvements of technology in the next CDMA base-station.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.353-360
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• 2017

Recently, due to physical limitation of Si based power semiconductor, development speed of switching power semiconductors is falling and it is difficult to expect any further performance improvements. SiC based power semiconductor with superior characteristic than Si-based power semiconductor have been developed to overcome these limitations. however, there is not method to apply for real system. Therefore, suggested the feasibility and solution for SiC-based power semiconductor system. design to 1kW class DC-DC boost converter and demonstrated the superiority of SiC MOSFET under the same operating conditions by analyzing switching frequency, duty ratio, voltage and current, and comparing with Si based power semiconductor through experimental efficiency according to each system load. The SiC MOSFET has high efficiency and fast switching speed, and can be designed with small inductors and capacitors which has the advantage of volume reduction of the entire system.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.4
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• pp.309-316
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• 2011

A PLL system has widely used for synchronizing the grid voltage at the grid-connected inverter for supplying power from the PV generation systems. In this paper, a PLL algorithm without both the loop filter and PI controller is suggested for improving the performance of synchronization at the single-phase and three-phase grid connected inverters. In order that the output voltage of a phase detector in the PLL has only a dc voltage, and it approaches to 0 when the synchronization signal is locked to the grid voltage, the feedback signals are determined by using two-phase voltages. After the PLL system with a proportional controller is modelled with the small signal analysis, the stability and steady-state error are investigated. Through the simulation studies and experimental results, the performances of the proposed PLL algorithm are verified.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.552-557
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• 2017

Wire, wireless digital broadcasting has sharply expanded with the birth of high definition TV since 2010, the use of duplex contents as well as simplex contents has rapidly increased. Currently, our satellite communications system adopted DVB by European digital broadcasting standardization organization as a standard of domestic data broadcasting, the method how to use selective contents has been studied variously according to the development of IPTV. Digital broadcasting utilizes the method using Transport Stream Packet(TSP) by the way of multiplexing of information in order to send multimedia information such as video, audio and data of MPEG-2, this streams include detail information on TV guide and program as well as video and audio information. In order to understand these data broadcasting system, this study realized TS analyzer that divides transport stream (TS) by packet in Linux environment, analyzes and prints by function, it can help the understanding of TS, the enhancement of stream parsing ability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1187-1195
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• 2013

Photovoltaic inverters should always track the maximum power of solar cell arrays in operation. Also, they should be irrespective of the maximum power point voltage of a wide range of solar cells in tracking the maximum power point. If the current ripple of solar cells occurs, the function of maximum power point tracking drops, and normal tracking is difficult when solar radiation or the maximum power point changes. To solve this problem, this paper proposed a new maximum power point tracking algorithm with high efficiency and an algorithm to reduce the current ripple of solar cells. According to the results from the test on 4KW grid-connected PV inverter, the efficiency of maximum power point tracking and inverter output and the total harmonic distortion of inverter output current showed 99.97%, 97.5% and 1.05% respectively. So, the inverter showed excellent performance, and made possible stable maximum power point tracking operation when the solar radiation rapidly changed from 100% to 10% and from 10% to 100% for 0.5 seconds.