• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.918-924
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• 2009

This paper deals with the experimental assessment of the vibration suppression of the smart structures. First, we have presented the paper about the new high-speed active control system that we have developed using the DSP320C6713 microprocessor and a peripheral system composed of a data acquisition system, A/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers using PA95. Since fast data processing is very important in the active vibration control of the structures, we utilized the fast processing DSP320C6713 microprocessor as a main processor to the controller and fast peripheral devices for fast control loop. To realize a fast active vibration control, we have analyzed and tested the processing time of the peripheral devices and provided the corresponding test results. Especially, we have focused on achieving the fast signal amplification of the PA95 device since it takes most of loop times of the control system. Finally, we performed numerous experiments of active vibration control of the aluminum plate to validate the superior performance of the developed control system based on previous mode tests of the plate.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4518-4526
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• 2023

NECP-SARAX is a neutronics analysis code system for advanced reactor developed by Nuclear Engineering Computational Physics Laboratory of Xi'an Jiaotong University. In past few years, improvements have been implemented in TULIP code which is the cross-section generation module of NECP-SARAX, including the treatment of resonance interface, considering the self-shielding effect in non-resonance energy range, hyperfine group method and nuclear library with thermal scattering law. Previous studies show that NECP-SARAX has high performance in both fast and thermal spectrum system analysis. The accuracy of TULIP code in fast and thermal spectrum system analysis is demonstrated preliminarily. However, a systematic verification and validation is still necessary. In order to validate the applicability of TULIP code for full energy range, 147 fast spectrum critical experiment benchmarks and 170 thermal spectrum critical experiment benchmarks were selected from ICSBEP and used for analysis. The keff bias between TULIP code and reference value is less than 300 pcm for all fast spectrum benchmarks. And that bias keeps within 200 pcm for thermal spectrum benchmarks with neutron-moderating materials such as polyethylene, beryllium oxide, etc. The numerical results indicate that TULIP code has good performance for the analysis of fast and thermal spectrum system.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1110-1119
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• 2020

The Floating Absorber for Safety at Transient (FAST) is a safety device used in the innovative Sodium-cooled Fast Reactor (iSFR). The FAST insert negative reactivity under transient or accident conditions. However, behavior of the FAST is still unclear under transient conditions. Therefore, the existing Floating Absorber for Safety at Transient Analysis Code (FASTAC) is improved to analyze the FAST movement by considering the reactivity and temperature distribution within the reactor core. The current FAST system is simulated under a single control rod withdrawal accident condition. In this investigation, the reactor thermal power does not return to its initial thermal power even if the FAST inserts negative reactivity. Only a 9 K of coolant temperature margin, in the hottest fuel assembly at EOL, can lead to unnecessary insertion of the negative reactivity. On the other hand, the FASTs cannot contribute to controlling the reactivity when normalized radial power is less than 0.889 at BOL and 0.972 at EOL. These simulation results suggest that the current FAST design needs to be optimized depending on its installed location. Meanwhile, the FAST system keeps the fuel, cladding and coolant temperatures below their limit temperatures with given conditions.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1986년도 추계학술발표회 논문집
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• pp.28-34
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• 1986

The frequency synthesizer for Fast Frequency Hopping System musy be capable of a fast tuning with a small step frequency over wide band. The most conventional frequency synthesizer that uses the phase locked loop (PLL) enables the wide band problem but have a poor side of the low resolution and the transient response. In this paper, we have discussed the experimental results of a direct digital frequency synthesizer which can be applicable to the Fast Frequency Hopping System, using digital-to-analoq (D/A)conversion techniques. With this system we can find the merits of a fine resolution and the possibility of a fast tuning leaving the problems of transent frequency.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1442-1450
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• 2017

In liquid metal fast breeder reactors, postulated failures of the plant protection system may lead to serious unprotected accidental consequences. Unprotected transients are generically categorized as transient overpower accidents and transient under cooling accidents. In both cases, core meltdown may occur and this can lead to a molten fuel coolant interaction (MFCI). The understanding of MFCI phenomena is essential for study of debris coolability and characteristics during post-accident heat removal. Sodium is used as coolant in liquid metal fast breeder reactors. Viewing inside sodium at elevated temperature is impossible because of its opaqueness. In the present study, a methodology to depict MFCI phenomena using a flat panel detector based imaging system (i.e., real time radiography) is brought out using a woods metal-water experimental facility which simulates the $UO_2-Na$ interaction. The developed imaging system can capture attributes of the MFCI process like jet breakup length, jet front velocity, fragmented particle size, and a profile of the debris bed using digital image processing methods like image filtering, segmentation, and edge detection. This paper describes the MFCI process and developed imaging methodology to capture MFCI attributes which are directly related to the safe aspects of a sodium fast reactor.

• 한국의류산업학회지
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• 제19권5호
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• pp.626-634
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• 2017

This study investigated garment formability of the 73 breathable fabrics for sports-wear garment and their fabric mechanical properties were measured using KES-FB and FAST systems. Predicted garment formability from the mechanical properties measured using KES-FB and FAST systems was compared and discussed with fabric structural parameters. In addition, virtual 3D simulation silhouette by I-designer CAD system wear appearance by simulation using 3D CAD system. And compared with FAST finger chart by mechanical properties of FAST system. The correlation coefficients of extensibility and shear modulus between KES-FB and FAST systems were high, however, bending rigidity and compressibility showed relatively low correlation coefficients. The correlation coefficient of garment formability of breathable fabrics between KES-FB and FAST systems was 0.82. It revealed that garment formability can be predicted from fabric mechanical properties by KES-FB and FAST systems. The garment formability of nylon breathable fabric was higher than that of PET one, and the garment formability of laminated breathable fabric showed the highest value compared to coated, dot and hot melt laminated breathable fabrics. It revealed that garment formability of breathable fabrics for sports-wear can be predicted from fabric mechanical properties and garment formability was dependent on the materials, finishing method and fabric structural parameters.

• Journal of Power Electronics
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• 제9권3호
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• pp.507-515
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• 2009

This paper proposes an autonomous decentralized control for a parallel connected uninterruptible power supply (UPS) system based on a fast power detection method using a FPGA based hardware controller for a single phase system. Each UPS unit detects only its output voltage and current without communications signal exchange and a quasi dq transformation method is applied to detect the phase and amplitude of the output voltage and the output current for the single phase system. Fast power detection can be achieved based on a quasi dq transformation, which results in a realization of very fast transient response under rapid load change. In the proposed method, the entire control system is implemented in one FPGA chip. Complicated calculations are assigned to hardware calculation logic, and the parallel processing circuit makes it possible to realize minimized calculation time. Also, an Nios II CPU core is implemented in the same FPGA chip, and the software can be applied for non-time critical calculations. Applying this control system, an autonomous decentralized UPS system with very fast transient response is realized. Feasibility and stable operation are confirmed by means of an experimental setup with three UPSs connected in parallel. Also, rapid load change is applied and excellent performance of the system is confirmed in terms of transient response and stability.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.272-272
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• 2012

Additional neutral particle analyzer has been installed to investigate the variation of fast ion tails with regard to the line of sight during 2012 KSTAR campaign. The system has the same photo-diode particle detector as previous system [1]. Both newly installed system and previous system modifield for 2012 campaign have two channels. One has a particle stopper transparent to hard X-ray, the other has no one. It will be used to separate the hard X-ray component from total hard X-ray and fast neutral counts. It is expected to measure fast ion tails more clearly through this extended system. A detailed system and calibration result will be presented in the conference.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
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• pp.480-483
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• 2008

다양한 인터넷 기술이 개발 및 발전됨에 따라 정보 제공자는 사용자에게 보다 효율적이고 고객중심의 서비스를 제공하기 위해 노력하고 있다. 특히 방대한 양의 정보에 대하여 고객이 원하는 정보를 정확하고 쉽게 제공하기 위해서는 검색기능의 효율성이 필수이다. 한국과학기술정보연구원(KISTI)에서는 국가과학기술포털서비스 성능향상을 위하여 FAST(Fast Search & Transfer ASA) 검색엔진을 도입하였다. 하지만 무엇보다도 서비스 환경에 적합하게 검색엔진의 하드웨어 및 소프트웨어적 성능을 최적화하는 것이 중요하다. 본 논문에서는 국가과학기술정보의 효율적 서비스를 위한 FAST 검색엔진 설계 및 최적화 기법에 대해 논한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1002-1008
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• 2011

Turnout is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction. there are classified variously according to rail type, sleeper type, fastening system, track type. Construction of concrete track are on the increase recently to secure the safety of track structure as well as to reduce the maintenance cost. SFC fastening system used the plain track a lot and for those reasons, The fast clip turnout demand growing to improving efficiency of the maintenance cost by unification of fastening clip on whole line. in this study is about development of the fastening system for new turnout using fast clip. this fastening system assembled elasticity pad underneath a base plate. its can change stiffness how to adjust contact surface area of elasticity pad Developed fastening system have passed test according to rule of KRS-TR0014-09R (rail fastening system) and Performance Certification by KR.