• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.184-191
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• 2015

As the power electronics system increases the frequency, the power loss and thermal management are paid more attention. This research presents a real time model of dissipation power with junction temperature response for 120kw IGBT inverter which is applied to the thermal management of high power IGBT inverter. Since the computational time is critical for real time simulation, look-up tables of IGBT module characteristic curve are implemented. The power loss from IGBT provides a clue to calculate the temperature of each module of IGBT. In this study, temperature of each layer in IGBT is predicted by lumped capacitance analysis of layers with convective heat transfer. The power loss and temperature of layers in IGBT is then communicated due to mutual dependence. In the dynamic model, PWM pulses are employed to calculation real time IGBT and diode power loss. Under Matlab/Simulink$^{(R)}$ environment, the dynamic model is validated with experiment. Results showed that the dynamic response of power loss is closely coupled with effective thermal management. The convective heat transfer is enough to achieve proper thermal management under guideline temperature.

• Smart Structures and Systems
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• 제4권6호
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• pp.809-828
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• 2008

Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.

• 한국지진공학회논문집
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• 제24권2호
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• pp.67-76
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• 2020

This study aims to optimize the cochlea-inspired artificial filter bank (CAFB) using El-Centro seismic waveforms and test its performance through a shaking table test on a two-span bridge model. In the process of optimizing the CAFB, El-Centro seismic waveforms were used for the purpose of evaluating how they would affect the optimizing process. Next, the optimized CAFB was embedded in the developed wireless-based intelligent data acquisition (IDAQ) system to enable response measurement in real-time. For its performance evaluation to obtain a seismic response in real-time using the optimized CAFB, a two-span bridge (model structures) was installed in a large shaking table, and a seismic response experiment was carried out on it with El-Centro seismic waveforms. The CAFB optimized in this experiment was able to obtain the seismic response in real-time by compressing it using the embedded wireless-based IDAQ system while the obtained compressed signals were compared with the original signal (un-compressed signal). The results of the experiment showed that the compressed signals were superior to the raw signal in response performance, as well as in data compression effect. They also proved that the CAFB was able to compress response signals effectively in real-time even under seismic conditions. Therefore, this paper established that the CAFB optimized by being embedded in the wireless-based IDAQ system was an economical and efficient data compression sensing technology for measuring and monitoring the seismic response in real-time from structures based on the wireless sensor networks (WSNs).

• 제어로봇시스템학회논문지
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• 제14권11호
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• pp.1117-1123
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• 2008

This paper implements dual-kernel system using standard Linux and real-time embedded Linux for the real-time control of intelligent robot systems. Such system provides more useful services including standard Linux thread that is easy to implement complicated tasks and real-time tasks for the deterministic response to velocity control. Here, an open source real-time embedded Linux, XENOMAI, is ported on embedded target board. And for interfacing with motor controller we adopted a real-time serial device driver. The real-time task was implemented with a priority to keep the cyclic control command for trajectory control. In order to validate deterministic response of the proposed system, the performance measurement of the delay in performing trajectory control with feedback loop is evaluated with non real-time standard Linux. The proposed software architecture is anticipated to take advantage of features in both standard Linux and real-time operating systems for the intelligent robot systems.

• 한국자원식물학회지
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• 제21권3호
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• pp.210-215
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• 2008

Gene-expression analysis is increasingly important in biological research, with real-time reverse PCR (RTPCR) becoming the method of choice for high-throughput and accurate expression profiling of selected genes. However, this technique requires important preliminary work for standardizing and optimizing the many parameters involved in the analysis. Plant stress studies are more and more based on gene expression. The analysis of gene expression requires sensitive and reproducible measurements for specific mRNA sequence. Several genes are regulated in response to abitoic stresses, such as salinity, and their gene products function in stress response and tolerance. The design of the primers and TaqMan probes for real-time PCR assays were carried out using the Primer $Express^{TM}$ software 3.0. The PCR efficiency was estimated through the linear regression of the dilution curve. To understand the expression pattern of various genes under salt stressed condition, we have developed a unique public resource of 9 stress-related genes in poplar. In this study, real-time RT-PCR was used to quantify the transcript level of 10 genes (9 stress-related genes and 1 house keeping gene) that could play a role in adaptation of Populus davidiana. Real-time RT-PCR analyses exhibited different expression ratios of related genes. The data obtained showed that determination of mRNA levels could constitute a new approach to study the stress response of P. davidiana after adaptation during growth in salinity condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.72-75
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• 2004

In this paper, the task assignment strategy considering communication delay and the priority of distributed tasks is proposed for the real-time network system in order to maximize the utilization of the system. For the task assignment strategy, the relationship among priority of tasks in network nodes, the calculation time of each task, and the end-to-end response time including the network delay is formulated firstly. Then, the task assignment strategy using the genetic algorithm is proposed to optimize the utilization of the system considering the LCM(Least Common Multiple) period. The effectiveness of proposed strategy is proven by the simulation for estimating the performance such as the utilization and the response time of the system in case of changing the number of tasks and the number of network nodes.

• Smart Structures and Systems
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• 제14권6호
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• pp.1269-1289
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• 2014

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.

• 인터넷정보학회논문지
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• 제16권6호
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• pp.31-37
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• 2015

최근 사물인터넷 발달로 인하여 센서에서 발생되는 데이터가 폭증하고 있다. 이러한 패러다임의 변화로 즉각 행동이 요구되는 여러 산업현장에서 실시간으로 발생되는 데이터들의 분석이 필요하게 되었으며, 실시간 시각화 분석이 대두되고 있다. 그러나 기존 시각화 시스템은 데이터를 저장 후에 시각화를 하기 때문에 서버의 응답시간이 실시간에 준하는 ms수준의 처리를 보장하지 못하며, 처리할 자원을 보유하고 있지 않아 주요 자원이 될 데이터를 폐기하는 문제가 발생한다. 따라서 본 논문에서는 가드닝 환경에서 IoT 센싱 정보를 활용하여 실시간 시각화 알고리즘을 적용한 스마트가드닝 시스템을 설계 및 구현하였다. 제안 시스템의 성능 평가를 위하여 서버의 응답시간을 측정하였고, 테스트 결과 제안하는 실시간 시각화 알고리즘의 응답 속도는 실시간에 준하는 ms수준의 처리를 보장함을 확인하였다.

• 한국정보과학회논문지:시스템및이론
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• 제36권1호
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• pp.9-20
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• 2009

마감시간이 있는 주기 태스크와 마감시간이 없는 비주기 태스크가 공존하는 결성 실시간 시스템에서는 주기 태스크의 마감시간과 비주기 태스크의 빠른 응답시간을 보장하는 것이 중요하다. 본 논문에서는 비주기 태스크 처리에 효율적이면서 잘 알려져 있는 알고리즘인 Total Bandwidth Server(TBS) 보다 향상된 알고리즘인 Enhanced TBS(ETBS)를 제시한다. ETBS는 Earliest Deadline First(EDF) 스케줄링 알고리즘을 사용하는 단일처리기 시스템에서 주기 작업의 단위 수행시간마다 확보할 수 있는 잉여 여유시간을 이용해 온라인으로 비주기 태스크에 마감시간을 부여하는 알고리즘이다. 제시한 알고리즘은 주기 및 비주기 태스크들이 처리기의 이용률을 모두 이용할 수 있게 하며 주어진 주기 태스크들의 마감시간을 보장한다. ETBS 알고리즘은 TBS와 같은 계산 복잡도 O(1)을 가지면서도 TBS보다 좋은 응답시간을 가짐을 이론적으로 보였고, 정량적인 응답시간 차이는 모의실험을 통해 보였다.

• International Journal of Automotive Technology
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• 제5권4호
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• pp.269-276
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• 2004

There has been considerable activity in recent years in developing timing analysis algorithms for distributed real-time control systems. However, it is difficult for control engineers to analyze the timing behavior of distributed real-time control systems because the algorithms was developed in a software engineer's position and the calculation of the algorithm is very complex. Therefore, there is a need to develop a timing analysis tool, which can handle the calculation complexity of the timing analysis algorithms in order to help control engineers easily analyze or develop the distributed real-time control systems. In this paper, an interactive timing analysis tool, called RAT (Response-time Analysis Tool), is introduced. RAT can perform the schedulability analysis for development of distributed real-time control systems. The schedulability analysis can verify whether all real-time tasks and messages in a system will be completed by their deadlines in the system design phase. Furthermore, from the viewpoint of end-to-end scheduling, RAT can perform the schedulability analysis for series of tasks and messages in a precedence relationship.