• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.176-179
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• 2001

RTDS는 실시간 디지털 시뮬레이터로서 전력계통에서 발생되는 각종 현상의 실시간 재현과 분석이 가능하다. 특히, 계통 모의를 효율적으로 수행할 수 있도록 자동모의기능 및 고장순서 지정을 위한 시퀀스 기능 등이 포함되어 있다 최근에는 계통의 과도 및 전압안정도의 효율적인 모의를 위한, RTDS ZIP 부하모델과 동적(Dynamic)부하 모델이 개발되었다. 따라서, 본 논문에서는 이러한 다양한 기능들과 RTDS 부하모델을 이용하여 계통의 안정도 모의를 훈련할 수 있는 케이스를 개발하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1119-1122
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• 2002

소규모의 기능별 시뮬레이션 모형을 운용하던 과거와는 달리 대규모이며 복잡한 시뮬레이션 시스템 구축이 요구되고 있는 현실에서, 대규모의 분산 시뮬레이션을 위한 하드웨어적인 기술 수준의 발전과 더불어 시뮬레이션 자체의 능력도 함께 발전시킬 필요성이 더욱더 커지고 있다. 본 연구에서는 차세대 시뮬레이션 기술 구조인 HLA(High Level Architecture) 기반 구조하에서 모형을 구축시 RTI(Run-Time Infrastructure)와 시뮬레이션 그리고 FOM(Federation Object Model)에 약간의 수정작업을 가하여, 네트워크의 트래픽을 감소시킴으로써 시뮬레이션의 능력을 향상시키는 방법을 모색하였다.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.135-141
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• 2014

This study was evaluated the linearity and reproducibility according to dose, and reproducibility according to delay time by changing tube current amount (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively, which are low energy radiations) using Glass Dosimeter (GD) and piranha semiconductor dosimeter which are used for measuring exposure dose. Measurements of radiation dose were performed using external detector of piranha 657 which is multi-function QA device (RTI Electronic, Sweden). Conditions of measurement were 80 kVp, SSD 100 cm and exposure region is $10cm{\times}10cm$. Glass dosimeter was exposed to radiation. Twenty-four glass dosimeters were divided into six groups (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively), then measured. This study was resulted by measuring the linearity and reproducibility according to change of tube current in low energy field. In dose characteristic of GD, this study could be useful as previous study with regard to dose characteristic according to change of tube voltage in low energy field.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.4
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• pp.628-645
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• 2010

To perform the engagement level simulation between the underwater vehicle model and the surface model those are constituted with various systems/ sub-systems, we implemented four different federates as a federation according to the IEEE 1516 HLA (High Level Architecture) protocol that is the international standard in the distributed simulation. Those are CFCS (Command and Fire Control System) federate, motion federate, external entities (torpedos, countermeasure and surfaceship) federate, and visualization federate that interacts with OSG (Open Scene Graph)-based visualization rendering module. In this paper, we present the detailed method about the model constitution for discrete event simulation in the distributed environment. For the sake of this purpose, we introduce the DEVS (Discrete Event System Specification)-HLA-based modeling method of the CFCS federate that reflects not only the interations between models, but also commands from user and tactics manager that is separated from the model. The CFCS federate makes decisions in various missions such as the normal diving, the barrier misision, the target motion analysis, the torpedo launch, and the torpedo evasion. In the perspective of DEVS modeling, the CFCS federate is the coupled model that has the tactical data process model, command model and fire control model as an atomic model. The message passing and time synchronization with other three federates are settled by the $m\ddot{a}k$ RTI (Runtime Infrastructure) that supports IEEE 1516. In this paper, we provides the detailed modeling method of the complicated model that has hierarchical relationship such as the CFCS system in the submarine and that satisfies both of DEVS modeling method for the discrete event simulation and HLA modeling method for the distributed simulation.

• Journal of Life Science
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• v.30 no.11
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• pp.939-946
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• 2020

Stroke is one of the leading causes of neurological disability worldwide and stroke patients exhibit a range of motor, cognitive, and psychiatric impairments. GPR88 is an orphan G protein-coupled receptor (GPCR) that is highly expressed in striatal medium spiny neurons; its deletion results in poor motor coordination and motor learning. There are currently no studies on the involvement of GPR88 in stroke or in post-stroke brain function recovery. In this study, we found a decrease in GPR88 protein and mRNA expression levels in an ischemic mouse model using Western blot and real-time PCR, respectively. In addition, we observed that, among the three types of cells derived from the brain (brain microvascular endothelial cells, BV2 microglial cells, and HT22 hippocampal neuronal cells), the expression of GPR88 was highest in HT22 neuronal cells, and that GPR88 expression was downregulated in HT22 cells under oxygen-glucose deprivation (OGD) conditions. Moreover, pretreatment with RTI- 13951-33 (10 mg/kg), a brain-penetrant GPR88 agonist, ameliorated brain injury following ischemia, as evidenced by improvements in infarct volume, vestibular-motor function, and neurological score. Collectively, our results suggest that GPR88 could be a potential drug target for the treatment of central nervous system (CNS) diseases, including ischemic stroke.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.802-807
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• 2012

The autothermal reforming of methane to syngas has been carried out in a reactor charged with both a Ni (15 wt%)-Ru (1 wt%)/$Al_2O_3$-MgO metallic monolith catalyst and an electrically-heated convertor (EHC). The standalone type reactor has a start-up time of less than 2 min with the reactant gas of $700^{\circ}C$ fed to the autothermal reactor. The $O_2/CH_4$ and $H_2O/CH_4$ ratio governed the methane conversion and temperature profile of reactor. The reactor temperature increased as the reaction shifted from endothermic to exothermic reaction with decreasing $H_2O/CH_4$ ratio. Also the amount of $CO_2$ in the products increases with increasing $H_2O/CH_4$ ratio due to water gas shift reaction. The 97% of $CH_4$ conversion was obtained and the reactor temperature was maintained $600^{\circ}C$ at the condition of $GHSV=10,000\;h^{-1}$ and feed ratio ($H_2O/CH_4=0.6$ and $O_2/CH_4=0.5$). In this condition, the maximum flow rate of the syngas generated from the reactor charged with 170 cc of the metallic monolith catalyst is $0.94\;Nm^3/h$.

• Journal of The Korean Association For Science Education
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• v.35 no.5
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• pp.907-917
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• 2015

Response to Intervention (RTI), which is focused on the gap between pre-interventions and post-interventions, provides an effective intervention program. This study takes under-achievement factors into consideration to determine the overall characteristics of underachievers. The under-achievement factors include cognitive learning factors, affective factors, and environmental factors. This study conducted curriculum-based assessments, achievement tests, and assessments on attitudes toward science and science learning motivation to verify the effects of individually tailored teaching according to the types of under-achievement in science. The experimental group was composed of six students in fourth grade, and the comparison group had 23 students. The findings of the study were as follows. First, the performance and progress of underachievers in the first-stage showed little progress and did not reach grade-level performance. Second, the underachievers in the second-stage greatly improved. In particular, the average of eight sessions in the second-step demonstrated performance beyond that of the regular child. Third, individually tailored teaching according to the types of under-achievement in science positively affected attitudes toward science and science learning motivation. This study will contribute to the improvement of the underachiever by applying individually tailored teaching according to the types of under-achievement in science.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.95-97
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• 2012

OMG(Object Management Group)의 데이터 분배 서비스(DDS: Data Distribution Service)는 발간(publish)/구독(subscribe) 모델에 기반하여 동일한 타입의 데이터를 실시간으로 주고 받는 데이터 중심의 분산 환경에서 많이 사용되는 통신 미들웨어 기술이다. 하지만 DDS는 실시간으로 발생하는 데이터에 대하여 일회성인 특징을 갖기 때문에 추후 데이터에 대한 분석, 검증 등을 위해 영속성을 제공할 필요성이 증대되고 있다. 이러한 추세를 반영하듯 RTI DDS, PrismTech Opensplice 등의 대표적인 DDS 시스템에서는 데이터베이스를 연동하기 위한 연구를 진행하고 있다. 실시간 통신 미들웨어인 DDS와 데이터베이스의 연동은 DBMS 애플리케이션이 일반적으로 데이터베이스를 사용하는 것뿐만 아니라 DDS의 시맨틱을 알지 못하더라도 데이터 중심의 발간/구독 모델을 유기적으로 활용할 수 있는 장점을 지닌다. 본 논문에서는 이를 위해 DDS 시스템인 DB-ReTiCom의 데이터베이스를 사용하기 위한 커넥티비티를 제안하고 사용자 친화적 인터페이스를 위한 변환 방법을 제시한다.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.179-183
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• 1996

Most of the conventional electrocardiogaphies fail to detect signals other than P-QRS-T due to the limited SNR and bandwidth. High-resolution electrocardiography (HRECG) provides better SNR and wider bandwidth for the detection of micro-potentials with higher frequency components such as ventricual late potentials(LP). In this paper, we developed a HRECG using uncorrected XYZ lead. The overall gain of the amplifier is 4000 and the bandwidth is $0.5{\sim}300Hz$ without using 60Hz notch filter. Three 16-bit AH converters sample X, Y, and Z signals simultaneously with a sampling frequency of 2000Hz. Sampled data are transmitted to PC via a DMA-controlled serial communication channel using RS-485 and HDLC protocol. The noise level of the developed HRECG is less than $5{\mu}V_{rms,\;RTI}$. In order to further reduce the noise level, signal averaging technique is implemented utilizing template matching method. The SNR of the developed HRECG is high enough for the detection of LP.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.123-126
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• 2011

최근 전투체계는 동시에 다수의 장비들 사이에 실시간으로 데이터를 전달해야 하는데, 이러한 특성을 만족하는 통신 미들웨어로서 OMG (Object Management Group)에서 정의한 데이터 분배 서비스 (DDS ; Data Distribution Service)가 적합하다. 이를 구현한 DDS 시스템에는 RTI의 NDDS, PrismTech의 OpenSplice, 충남대학교의 ReTicom 등이 있다. 이 중 NDDS와 OpenSplice는 데이터의 영속성을 지원하지만 ReTicom에서는 영속성을 아직 지원하지 못한다. 이를 해결함과 동시에 실시간성을 보장하기 위해서 ReTicom은 메인 메모리 기반의 객체 관계형 데이터베이스를 사용하여 구현중이다. 이를 위해서는 DDS의 객체 모델 데이터를 정의하는 IDL과 객체 관계형 데이터베이스의 데이터 타입 및 구조 등이 동일하지 않기 때문에 IDL과 객체 관계형 데이터베이스간의 데이터 타입 및 구조를 변환하는 메타 모델 변환 방법이 제공되어야 한다. 본 논문에서는 이러한 메타 모델 변환 방법을 해결하고자 IDL을 구조파악이 쉬운 XML 스키마로 변환 후 이를 객체 관계형 데이터베이스의 데이터 타입 및 구조 형태로 변환 해주는 방법을 제안한다.