• ETRI Journal
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• 제37권6호
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• pp.1143-1153
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• 2015

In this paper, we propose an efficient architecture for a real-time image stitching engine for vision SoCs found in motor vehicles. To enlarge the obstacle-detection distance and area for safety, we adopt panoramic images from multiple telegraphic cameras. We propose a stitching method based on a fixed homography that is educed from the initial frame of a video sequence and is used to warp all input images without regeneration. Because the fixed homography is generated only once at the initial state, we can calculate it using SW to reduce HW costs. The proposed warping HW engine is based on a linear transform of the pixel positions of warped images and can reduce the computational complexity by 90% or more as compared to a conventional method. A dual-core SW/HW image stitching engine is applied to stitching input frames in parallel to improve the performance by 70% or more as compared to a single-core engine operation. In addition, a dual-core structure is used to detect a failure in state machines using rock-step logic to satisfy the ISO26262 standard. The dual-core SW/HW image stitching engine is fabricated in SoC with 254,968 gate counts using Global Foundry's 65 nm CMOS process. The single-core engine can make panoramic images from three YCbCr 4:2:0 formatted VGA images at 44 frames per second and frequency of 200 MHz without an LCD display.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제2권1호
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• pp.20-29
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• 1992

In $BaTiO_3-NaNbO_3$ system, complete series of solid solution occurs and $30BaTiO_3{cdot}70NaNbO_3$ composition is congruently melted. Single crystals of $30BaTiO_3{cdot}70NaNbO_3$, composition were grown by Czochralski method in this investigation. Single crystals with dimensions of 15 - 20mm diameter and 20 - 30mm length, were grown at the pulling rate of 2.0mm/h and the rotation rate of 5.0 -l0rpm. Core structures were found in the grown crystals and inclusions, cellular boundaries existed at the core region. The origin of core occuring was unstability of the crystal- melt interface due to the poor conductivity of latent heat through the crystal during the crystal growing process. Obtained crystals were optically homogeneous except the core region and showed high optical transmittance in the visible range.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.554-564
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• 2022

The natural circulation phenomena occurring in fully integrated nuclear reactors are associated with a unique formation mechanism. The phenomenon results from a structural feature of these reactors involving upward flow from the core, located in the central-bottom region of a single vessel, and downward flow to the steam generator in the annulus region. In this study, to understand the natural circulation in a single vessel involving a multi-layered flow path, single-phase and two-phase natural circulation tests were performed using the SMART-ITL facility, and validation analysis of the TASS/SMR-S code was performed by comparing the corresponding test results. Three single-phase natural circulation tests were sequentially conducted at 15%, 10%, and 5% of full-scaled core-power without RCP operation, following which a two-phase natural circulation test was successively conducted with an artificial discharge of coolant inventory. The simulation capability of the TASS/SMR-S code with respect to the natural circulation phenomena was validated against the test results, and somewhat conservative but reasonably comparative results in terms of overall thermalhydraulic behavior were shown.

• Proceedings of the Korean Society of Computer Information Conference
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• 한국컴퓨터정보학회 2017년도 제56차 하계학술대회논문집 25권2호
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• pp.271-274
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• 2017

통합 ECU를 구현할 시, 구현단계 이전에 어떤 코어를 적용 시킬지를 판단하여 추후 발생할 수 있는 비용, 성능, 소요 시간 등의 문제점을 미리 대비할 수 있는 방안이 필요하다. 따라서 본 논문에서는 차량 통합ECU에서 싱글코어와 멀티코어 프로세서 중 어떤 프로세서를 적용하는 것이 효율적인 것인지 판단하는 연구를 진행했다. 통합 ECU의 기능이 결정된 경우, 구현이전의 설계 단계에서 기능적 요구 사항들을 고려하여 SW Task를 HW 모델에 적용했을 때의 효과를 분석했다. 분석 된 결과를 토대로 통합 ECU 모델의 싱글 및 멀티 코어 방식에 따른 성능을 비교했다. 본 논문에서 제안한 분석 방안을 적용하면 구현 단계 이전에 통합 ECU에 필요한 프로세서의 성능을 파악할 수 있다. 또한, 통합 ECU 구현 비용 및 개발 소요 시간을 줄일 수 있는 효과를 불러올 수 있을 것으로 예상한다.

• Journal of Magnetics
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• 제22권2호
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• pp.196-202
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• 2017

The occurrence of ferroresonance in electrical systems including nonlinear inductors such as transformers will bring a lot of malicious damages. The intense ferromagnetic saturation of the iron core is the most influential factor in ferroresonance that makes nonsinusoidal current and voltage. So the nonlinear behavior modeling of the magnetic core is the most important challenge in the study of ferroresonance. In this paper, the ferroresonance phenomenon is investigated in a single phase transformer using the finite element method and considering the hysteresis loop. Jiles-Atherton (JA) inverse vector model is used for modeling the hysteresis loop, which provides the accurate nonlinear model of the transformer core. The steady-state analysis of ferroresonance is done while considering different capacitors in series with the no-load transformer. The accurate results from copper losses and iron losses are extracted as the most important specifications of transformers. The validity of the simulation results is confirmed by the corresponding experimental measurements.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권10호
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• pp.1536-1541
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• 2012

The study analyzed problems by iron core structure of the three phased transformer on asymmetric three phase lines, which included line disconnections, ground faults, COS OFF, and unbalanced loads on the power distribution system. In particular, by analyzing PT combustion cases within the MOF, the study was able to analyze the combustion cause of the core-type transformer and its effect on the system, conduct simulations and practice demonstrations on the characteristics for each iron core structure of the three phase transformer using PSCAD/EMTDC, and suggest measures to prevent the combustion of the core-type transformer.

• Journal of the Korean Ceramic Society
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• 제34권10호
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• pp.1015-1020
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• 1997

In the Nd;YAG crystal growth by Czochralski method, the relationship between the core formation and the solid-liquid interface was observed by controlling the temperature gradient in the furnace. When the crystal was grown along<111> direction, defects and core area were reduced as the temperature gradient increased. The optimum temperature gradient was found to be higher than 4$0^{\circ}C$/cm. The Nd3+ concentration analysis by ICP-Mass showed that the segregation coefficient was about 20% higher in the core region than core-free region, where the segregation coefficients of core region and core-free region were 0.22 and 0.18, respectively.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.238-247
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• 2020

The Burnable Poison (BP) is very important for all Light Water Reactors in order to hold-down the initial excess reactivity and to control power peaking. The use of BP is even more essential as the excess reactivity increases significantly with a longer operation cycle. In this paper a feasibility study was conducted in order to investigate the benefits of a new combinational BP concept designed for 24-month cycle PWR core. The reference designs in this study are based on the two Korean fuel assemblies; 17 × 17 Westinghouse (WH) design and 16 × 16 Combustion Engineering (CE) design. A modification was done on these two designs to extend their cycle length from 18 months into 24 months. DeCART2D-MASTER code system was used to perform assembly and core calculations for both designs. A preliminary test was conducted in order to choose the best BP suitable for 24-month as a representative for single BP concept. The comparison between the results of two concepts (combinational BP concept and single BP concept) showed that the combinational BP concept can replace the single BP concept with better performance on holding down the initial excess reactivity without violating the design limitations.

• The Journal of Korean Physical Therapy
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• 제31권2호
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• pp.103-110
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• 2019

Purpose: This study evaluated the usefulness of International Classification of Functioning, disability and health core set for children and youths with cerebral palsy (ICF-core set for CP) by comparing the Gross Motor Function Measure-88 (GMFM-88), which is the most widely used outcome measure in children with cerebral palsy (ICF-core set for CP). Method: One subject (Female, 14) was evaluated by GMFM-88 and ICF-core set for CP. In addition, the concept of GMFM-88 was compared with the concept of the ICF-core set for CP in compliance with ICF linking rules. The numerical values both of the GMFM-88 categories and the ICF-core set for CP's items were compared. Results: The ICF b760 was linked to the GMFM-88 59~61. d415 was linked to 57~58 of GMFM-88. d450 was linked to GMFM-88's 65~72. d455 was linked to GMFM-88 at 77and 80~83. Conclusion: The association of the ICF-core set for CP and GMFM-88 was confirmed. In addition, the number of categories of ICF-core set for CP was smaller than the number of items of GMFM-88. In conclusion, the ICF-core set for CP is an evaluation tool that can identify the various features of children. In addition, GMFM-88 was linked to the ICF core set for CP according to the ICF linking rules.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.54-67
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• 2018

There have been recent efforts to establish methods for high-fidelity and multi-physics simulation with coupled thermal-hydraulic (T/H) and neutronics codes for the entire core of a light water reactor under accident conditions. Considering the computing power necessary for a pin-by-pin analysis of the entire core, subchannel-scale T/H analysis is considered appropriate to achieve acceptable accuracy in an optimal computational time. In the present study, the applicability of in-house code CUPID of the Korea Atomic Energy Research Institute was extended to the subchannel-scale T/H analysis. CUPID is a component-scale T/H analysis code, which uses three-dimensional two-fluid models with various closure models and incorporates a highly parallelized numerical solver. In this study, key models required for a subchannel-scale T/H analysis were implemented in CUPID. Afterward, the code was validated against four subchannel experiments under unheated and heated single-phase incompressible flow conditions. Thereafter, a subchannel-scale T/H analysis of the entire core for an Advanced Power Reactor 1400 reactor core was carried out. For the high-fidelity simulation, detailed geometrical features and individual rod power distributions were considered in this demonstration. In this study, CUPID shows its capability of reproducing key phenomena in a subchannel and dealing with the subchannel-scale whole core T/H analysis.