• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.182-187
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• 2012

Since PV PCS uses output current sensor for ac output current control, the sensor's sensing value includes unnecessary offset inevitably. If PV inverter is controlled by the included offset value, it's output current will generate DC offset. The DC offset of output current for trans-less PV inverter is fatal to grid, which results in saturating grid side transformer. Usually DSP controller of PV inverter reads several times sensing value during initial operation and, finally, it's average value is used for offset calibration. However, if temperature changes, the offset changes, too. Therefore, output current sensor measures sensing value that includes offset again. In this paper we propose new algorithm where two identical forward and reverse sensors are used to calculate the offset in real time. As a result the offset is not correlated with temperature change. The proposed algorithm is verified through PSIM simulation for validity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1637-1639
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• 2014

In the past, the analog protection relays have been widely used for the safety-related systems in the nuclear power plants due to their stability and reliability. Meanwhile, as the high performance digital system has been developed, the digital systems have been adopted in the non-safety systems. However, since the digital systems currently used in the non-safety systems were not developed according to Q-class standard, Commercial Grade Item Dedication (CGID) procedure should be performed in order to apply them to the safety-related system. The purpose of this paper is to describe the CGID procedure including the analysis of the hardware architecture as well as the software embedded in protective relay to apply to the emergency diesel generator in the nuclear power plant. The entire CGID procedure was performed strictly according to the international standard and regulations.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.2
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• pp.75-81
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• 2018

In this paper for developing and implementing the car driver's front lane attention enhancement developed system using the car camera. The developed system automatically alarm the car driver when front cars make the dangerous situation. We use Raspberry Pi camera module V2 as car camera module, Raspberry Pi 3 board as hardware main board of implementing embedded system and develop the application library module which can be operated on the Raspberry situation. The application library module widely consist of two part, front car recognition part and dangerous situation distinguish part. Our developed system satisfy the performance test of the target system at the software test certification laboratory of TTA(Telecommunication Technology Association). We test four items as attentive car recognition ability at day and night, system performance, response time. We get the performance of developed system based on the four goal. The car driver's front lane attention enhancement system in this paper will be widely used at the ADAS(Advanced Driving Assistance System) because of the better performance and function.

• Journal of Drive and Control
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• v.15 no.1
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• pp.10-15
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• 2018

The hydraulic cylinder seals are used not only to protect leakage of the working fluids but also to prevent incoming of foreign particles into the system. Chromium plating is generally applied to improve corrosion and wear resistance. It has been noticed that sealing surface damage occurs due to the hard foreign/wear particles contained in the hydraulic oil. In this study, a three-bodied sliding contact problem related with a PTFE seal, a spherical particle and chrome-plated steel substrate is modeled to investigate the relations to wear mechanism. Using the nonlinear finite element software, MARC/MENTAT, the deformed shapes, the von Mises and first principal stress distributions with plating thickness were compared. The sealing surface was mainly abraded by hard particles embedded in the seal. The plastic deformation of the steel substrate decreased with thicker plating. Hence it could be more effective to coat the sealing surface of a hydraulic cylinder with a hard material such as TiN, TiC and DLC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.656-658
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• 2013

Due to increasing demand of new technology, the complexity of hardware and software consisting embedded systems is rapidly growing. Consequently, it is getting hard to design complex devices only with traditional methodology. In this contribution, I introduce a new approach of designing complex hardware with SystemVerilog. I adopted the idea of object oriented implementation of the SystemVerilog to the design of an elliptic curve crypto-engine server farm. I successfully implemented the whole system including the test bench in one integrated environment, otherwise in the traditional way it would have cost Verilog simulation and C/SystemC verification which means much more time and effort.

• Annual Conference of KIPS
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• 2016.10a
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• pp.497-500
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• 2016

최근 임베디드 소프트웨어의 신뢰성과 안전성을 보장하기 위하여 코딩룰인 MISRA-C를 자동차 뿐만 아니라 군사, 의료 분야등 광범위한 분야에서 이용하고 있다. 하지만 MISRA-C가 자동차 시스템분야의 MISRA 가이드를 이용하여 개발되었기 때문에 타 분야의 분야별 특성을 모두 고려하지 못한다는 문제점이 제시되고 있다. 따라서 본 논문에서는 향후 의료기기 분야의 특성을 고려한 코딩룰을 제시하기에 앞서, 의료기기 소프트웨어에서의 코딩룰 필요성을 제시한다. 이를 위해 개발 단계의 의료기기 소스코드에 MISRA-C를 적용하여 정적 분석을 해보고, 적용 유무 따른 실행시간 오류 결과를 분석한다. 분석 결과, 코딩룰을 이용하면 실질적으로 실행시간 오류 발생을 막을 수 있고, 적용 과정에서 기타 다른 실행시간 오류들 또한 해결됨을 확인하였다. 위 결과로 본 논문에서는 의료 분야의 특성을 고려한 특화 코딩룰의 필요성을 제시한다.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1418-1429
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• 2004

This paper presents GrammE, a grammar development environment for feature-based APSG. At the stage of a grammar development, analysis are be done by interpreting the grammar under development, given in a text format, it is relatively easy to diagnose the grammar. Once developed, the grammar is compiled, by using the embedded grammar compiler, into a parser program written in $C^{++}$. The parser program can be used in various types of natural language processing systems requiring syntactic analysis. GrammE is language-independent, and so far has been used for the development of Korean and Chinese grammars.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.2
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• pp.123-132
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• 2014

In this paper, an IEEE1588 based clock synchronization technique for CAN (Controller Area Network) is presented. Clock synchronization plays a key role to the success of a networked embedded system. Recently, the IEEE1588 algorithm making use of dedicated chipsets has been widely adopted for the synchronization of various industrial applications using Ethernet. However, there is no chipset available for CAN. This paper presents the implementation of IEEE1588 for CAN, which is implemented using only software and CAN packets without any dedicated chipset. The proposed approach is verified by the comparison between the estimated synchronization precision with a simple model and the measured precision with experimental setup.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.3
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• pp.13-21
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• 2007

A forklift is a motive machine powered by LPG, diesel engine or electric motors. The internal combustion engine type forklift is equipped with automatic transmission to meet the required drive load as well as the easy operation of the vehicle. This paper deals with the shift control and endurance test controller which is developed for the functional test of the newly designed automatic transmission on a dynamometer test bench. Its major function is to control the proportional solenoid currents, which is directly related to clutch pressures, for the given reference current trajectory during shift and sequential operation of shift schedule designed for the durability test at each gear. It also has the ability to monitor all the necessary test data through RS232 communication and log them to disk files. The current controller of embedded system is designed from the identified dynamics of solenoid coil and the current reference can be easily modified with a user interface software on PC so as to match the shift data by experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.353-354
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• 2006

The automatic inspection system is developed for the formed end part of automotive fuel pipe. The developed system has functions of outer diameter and formed end length measurement by LVDT(linear variable differential transformer) together with burr cleaning of automotive fuel pipe. The measured data are managed and controlled in real time by embedded SPC(statistical process control) program. The system is composed of mechanical part, electronic part and developed software system. These three parts operate automatically by mutual communication with each other. The developed system showed good results in finding inferior goods and efficiency improvement of the fuel pipe production line. It also eliminated the unreliable manual inspection processes and improved the confidence of product quality.