• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3897-3908
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• 2022

High-fidelity nuclear data libraries and neutronics simulation tools are essential for the development of fast reactors. The IAEA coordinated research project on "Neutronics Benchmark of CEFR Start-Up Tests" offers valuable data for the qualification of nuclear data libraries and neutronics codes. This paper focuses on the verification and validation of the CEFR start-up modelling using OpenMC Monte-Carlo code against the experimental measurements. The OpenMC simulation results agree well with the measurements in criticality, control rod worth, sodium void reactivity, temperature reactivity, subassembly swap reactivity, and reaction distribution. In feedback coefficient evaluations, an additional state method shows high consistency with lower uncertainty. Among 122 relative errors in the benchmark of the distribution of nuclear reaction, 104 errors are less than 10% and 84 errors are less than 5%. The results demonstrate the high reliability of OpenMC for its application in fast reactor simulations. In the companion paper, the influence of cross-section libraries is investigated using neutronics modelling in this paper.

• 융합경영연구
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• 제11권1호
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• pp.31-44
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• 2023

Purpose: This study aims to figure out the characteristics of corporate life cycle and resource input in terms of the sustainability diagnosis of pharmaceutical companies in Korea. Research design, data, and methodology: Using the Gompertz model under the assumption that companies have finite resources, this study tries quantitative interpretation of life cycle and resource input pattern for longevity companies with 25 years of experience among 158 pharmaceutical companies listed on Korean stock market based on maturity of revenue. Results: The study found revenue maturity through Gompertz model was statistically correlated with enterprise value. According to the life cycle analysis, more than 95% of 59 pharmaceutical companies were in the growth and maturity phase and have an average life cycle of 88 years and an average remaining life of 52 years. Regarding maturity profile of resource input, maturity of employees was generally high more than 60% and this meant there was jobless growth in Korean pharmaceutical industry. Conclusion: This study demonstrated there is a high statistical correlation between the maturity of a company's resource input and its revenue and enterprise value. It is believed that these results could be utilized as a basis for high fidelity function that predict revenue and enterprise value based on resource input information.

• 대한영상의학회지
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• 제84권1호
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• pp.240-252
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• 2023

목적 소아 환자에서 두부 컴퓨터단층촬영(이하 CT)에 대한 딥러닝 이미지 재구성(deep learning image reconstruction; 이하 DLIR; TrueFidelity; GE Healthcare, Milwaukee, WI, USA)의 효과를 평가하고자 한다. 대상과 방법 총 126개의 소아 두부 CT 이미지를 수집했으며, adaptive statistical iterative reconstruction (이하 ASiR)-V를 사용한 반복적 재구성 및 세 가지 수준의 DLIR을 사용한 재구성을 시행하였다. 각 이미지 세트 그룹은 환자의 연령에 따라 4개의 그룹으로 구분하였으며 각 연령군의 임상 및 방사선량 관련 데이터를 검토하였다. 양적 매개 변수에는 signal to noise ratio (이하 SNR) 및 contrast to noise ratio (이하 CNR)가 포함되었으며 질적 매개 변수로 영상의 잡음(noise), 회백질의 구분 정도, 선명도, 인공물 및 수용 가능성(acceptability), 영상의 질감이 포함되었고 이에 대한 평가와 비교를 시행하였다. 결과 모든 연령 그룹의 모든 수준의 SNR 및 CNR은 높은 수준의 DLIR 사용 시 증가하였다. ASiR-V와 비교했을 때 높은 수준의 DLIR은 SNR 및 CNR이 개선되었다(p < 0.05). 그리고 DLIR의 수준이 증가될수록 순차적인 잡음 감소, 회백질 구분 개선, 선명도 개선이 나타났다. 이러한 변수들에서 높은 수준의 DLIR 사용 시 ASiR-V와 유사한 정도의 수치가 측정되었다. 인공물과 수용 가능성의 경우에 적용된 DLIR 수준 간에 큰 차이를 보이지 않았다. 결론 소아 두부 CT에 고수준 DLIR을 적용하면 영상의 노이즈를 줄일 수 있으나 인공물 처리에 대한 개선이 필요하다.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.561-568
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• 2006

CFD simulation for one of tilt-rotor UAV configurations, TR-E2S1, was performed to investigate its aerodynamic characteristics. Control surfaces such as elevator and rudder were deflected and wing incidence angle was changed. Also aerodynamic stabilities were analyzed with the variation of pitch and yaw angles. The comparison of CFD with wind tunnel test results reveals the same trends in the aerodynamic characteristics and stabilities. However 12% scale wind tunnel test model is too small for accurate data collection and should build a high fidelity model for quantitative data comparison.

• Structural Engineering and Mechanics
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• 제11권2호
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• pp.133-149
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• 2001

A high-fidelity model of a tracked vehicle traversing a flexible ground terrain with a varying profile is presented here. In this work, we employed a recursive formulation to model the track subsystem. This method yields a minimal set of coordinates and hence, computationally more efficient than conventional approaches. Also, in the vehicle subsystem, the undercarriage frame is assumed to be connected to the chassis by a revolute joint and a spring-damper unit. This increase in system mobility makes the model more realistic. To capture the vehicle-ground interaction, a Winkler-type foundation with springs-dampers is used. Simulation runs of the integrated tracked vehicle system for vibrations for four varying ground profiles are provided.

• 대한기계학회논문집 C: 기술과 교육
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• 제3권2호
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• pp.97-106
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• 2015

Flexible structures are often important components of mechanical assemblies in motion. A flexible structure sometimes must go through assembly steps that cause it to be in a pre-stressed condition when in the starting position for operation. A virtual prototype of the assembly must also bring the model of the flexible structure into the same pre-stressed condition in order to obtain accurate simulation results. This case study is presented regarding the simulation of a constant velocity joint, with a focus on the flexible boot. The case study demonstrates that careful definition of the initial conditions of the boot and flexible body contacts yields high-fidelity simulation results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.106.2-106.2
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• 2010

IGCC (Integrated Gasification Combined Cycle) plants are among the most advanced and effective systems for electric energy generation. From a control perspective, IGCC plants represent a significant challenge: complex reactions, highly integrated control to simultaneously satisfy production, controllability, operability and environmental objectives. While all these requirements seem clearly to demand a multivatiable, model predictive approach, not many applications can be easily found in the literature. This paper describes the IGCC dynamic simulation that is capable of simulating plant startup, shutdown, normal, and abnormal operation and engineering studies. This high fidelity dynamic models contain the detailed process design data to produce realistic responses to process operation and upset. And the simulation is used by engineers to evaluate the transient performance and produce graphical information indicating the response of the process under study conditions.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.15-23
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• 2006

본 논문은 다양한 형태의 객체데이터를 포함하는 하이브리드환경에 대한 안정적이고 사실적인 햅틱 제시 방법을 제안한다. 제안된 방법은 가상객체를 기술하는 방법에 의존하지 않고 일관된 방법으로 충돌검출 및 반력계산을 수행한다. 따라서 사용자 및 개발자는 부가적인 노력 없이 다양한 컨텐츠를 활용할 수 있으며, 빠르고 쉽게 가상환경을 구축할 수 있다. 또한 제안된 방법은 멀티 스레드로 구현된 안정화 연산을 수행하며, 이를 통해 느린 햅틱랜더링 속도를 가지는 환경에 대해서도 안정적이고 사실적인 역감을 제시한다. 따라서 제안된 방법은 다양한 응용분야에서 햅틱기술을 보다 쉽고 보다 효과적으로 적용할 수 있는 기회를 제공할 수 있다.

• 기본간호학회지
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• 제22권2호
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• pp.180-189
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• 2015

Purpose: The purpose of this study was to identify the types of errors that occurred and were recovered in a simulated transfusion scenario by nursing students. Methods: Twenty-eight teams of a total of 89 nursing students participated in a transfusion simulation using a high fidelity simulator. Data were collected by observing rule based errors and built in errors recovered according to the framework of Eindhoven model. Reflective journaling was used to identify perceived safety-threatening errors and commitment to improvement. Data were analyzed using descriptive statistics. Results: All teams committed the rule based errors in the scenario. The most common errors occurred in the coordination category related to communication with physician. Most of students perceived the transfusion reaction as a safety-threatening error. Conclusion: The findings indicate that students lack patient safety competence. The simulation training to decrease errors and improve safe practice provides nursing students with an effective strategy to develop patient safety competence.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.279-282
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• 2000

As digital systems continue to use components with faster edge rates and clock speeds, transmission of the digital information in these systems approaches the microwave realm. At these speeds digital signal fidelity becomes both a critical success factor and design challenge. The noise sources in digital systems include the noise in power supply, ground and packaging media due to simultaneous switching of drivers, signal reflections and distortions on single and multiple transmission lines. This paper presents theory, case studies and design considerations of gigabit interconnection for network and communication systems. The case studies show HSPICE and Ampredictor simulations of alternate approaches. Various subjects including skin effect and dielectric losses, interconnect simulations and crosstalks of connector, affected signal discontinuity, are addressed.