• International Journal of Naval Architecture and Ocean Engineering
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• 제10권5호
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• pp.596-608
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• 2018

The present study aims to assess test uncertainty assessment method of nominal wake field measurement by a Stereoscopic Particle Image Velocimetry (SPIV) system in a towing tank. The systematic uncertainty of the SPIV system was estimated from repeated uniform flow measurements. In the uniform flow measurement case, time interval between image frames and uniform flow speed were varied to examine the effects of particle displacement and flow around the SPIV system on the systematic standard uncertainty. The random standard uncertainty was assessed by repeating nominal wake field measurements and the estimated random standard uncertainty was compared with that of laser Doppler velocimetry. The test uncertainty assessment method was applied to nominal wake measurement tests of a very large crude oil carrier model ship. The nominal wake measurement results were compared with existing experimental database by other measurement methods, with its assessed uncertainty.

• 전기학회논문지
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• 제60권6호
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• pp.1261-1267
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• 2011

Electricity meters using in Korea are about 1.8 million units. From among these, electronic meters for high voltage, about 170 thousand units were installed to the digital type meter and ones for low voltage installed hundreds of thou-sands of meters through a model project. Recently, low voltage meter are expected to complete the installation within several years. Domestic power metering technology is being beyond a simple framework with an electronic type and is rapidly evolving to intelligent smart metering systems in conjunction with promotion of a national smart grid project. Accordingly, it is important to ensure an immunity of meter for electromagnetic field and environmental noise at the installation site. In this paper, we are going to check the validity of international standard that focusing on RF electromagnetic field immunity of meter to secure the quality and improve the reliability in field operation of meter. And we will verify the validity of test specification focused on actual installation environment and are going to offer the improvement plan of test standard.

• 전기학회논문지P
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• 제66권4호
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• pp.163-168
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• 2017

This paper presented an evaluation method for the efficiency uncertainty of a three-phase induction motor using finite element analysis. The motor efficiency in the finite element analysis is calculated by the loss separation method as in the actual test. In the process of evaluating the efficiency uncertainty, the difference between the finite element analysis and the actual test is the method of calculating the type-A / B standard uncertainty of the input quantity to estimate the efficiency and each losses. For the input quantities which can confirm the instantaneous values with respect to time, the type-A standard uncertainty in the finite element analysis is calculated from the RMS values or average values having separate periods in the steady state. And, the type-B standard uncertainty in the finite element analysis is assumed to be zero. Also, this paper compared and analyzed the efficiency uncertainty evaluated by the proposed method and the efficiency uncertainty through the actual test.

• 한국항해항만학회지
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• 제44권2호
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• pp.98-109
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• 2020

In recent years, there have been concerted efforts toward predicting ship maneuvering in shallow water since the majority of ship's accidents near harbors commonly occur in shallow and restricted waters. Enhancement of ship maneuverability at the design stage is crucial in ensuring that a ship navigates safely. However, though challenging, establishing the mathematical model of ship maneuvering motion is recognized as crucial toward accurately predicting the assessment of maneuverability. This paper focused on a study on sensitivity analysis of the hydrodynamic coefficients on the maneuverability prediction of KVLCC2 in shallow waters. Hydrodynamic coefficients at different water depths were estimated from the experimental results conducted in the square tank at Changwon National University (CWNU). The simulation of standard maneuvering of KVLLC2 in shallow waters was compared with the results of the Free Running Model Test (FRMT) in shallow waters from other institutes. Additionally the sensitivity analysis of all hydrodynamic coefficients was conducted by deviating each hydrodynamic derivative from the experimental results. The standard maneuvering parameters including turning tests and zig-zag maneuvers were conducted at different water depths and their effects on the standard maneuvering parameters were assessed to understand the importance of different derivatives in ship maneuvering in shallow waters.

• Journal of Korean Biological Nursing Science
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• 제18권4호
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• pp.274-279
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• 2016

Purpose: Adolescents who experienced the alcohol consumption have gradually increased. Adolescence is a critical period of the neural plasticity in the brain. Neural plasticity is mediated by neurotrophins and has an impact on cognitive function. Environmental enrichment ameliorates the cognitive function and increases neurotrophins. Thus, we investigated the neuroprotective effect of environmental enrichment on ethanol induced cognitive impairment in adolescent rats. Methods: The ethanol groups and the controls groups were injected with ethanol (0.5g/kg) and phosphate buffered saline, respectively, through intraperitoneal from 28th day of birth for 11 days. The environmental enrichment groups were provided larger cages containing toys than the standard cage. Passive avoidance test and Y-maze test were performed to evaluate the spatial memory. Results: Environmental enrichment+ethanol group showed higher alterations than the standard environment+ethanol group in Y-maze test (p<.05). In hippocampus, The environmental enrichment+ethanol group showed significantly higher level of the number of c-fos positive celsl and density of tropomyosin receptors kinase B receptor than the standard environment+ethanol group (p<.05). Conclusion: So, we suggested that the environmental enrichment played a role as a prophylaxis for prevention of memory impairment induced by ethanol exposure in adolescence.

• 한국콘텐츠학회논문지
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• 제16권4호
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• pp.418-425
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• 2016

본 논문에서는 지식기반 기법에서 한국어 명사의 의미중의성 해소에 유용한 품사집합을 제시한다. 세종 형태의미분석 말뭉치에서 174,000 문장을 추출하여 테스트 셋으로 이용하고, 표준국어대사전의 뜻풀이와 용례를 이용하여 각 문장의 의미중의성을 해소하였다. 그 결과 전체 테스트 셋의 성능을 가장 좋게하는 15개의 품사집합과 단어별 평균을 가장 높게 하는 17 개의 품사집합이 제시되었다. 실험결과 45 개의 전체 품사집합을 이용하는 것보다 정확도가 최대 12%까지 향상되었다.

• 한국해양공학회지
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• 제26권6호
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• pp.33-38
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• 2012

In our study, a closed-type penetration unit for standard penetration test (SPT) equipment was developed in order to operate in an underwater environment. This type causes energy dissipation, mainly due to the small gap between an airtight case and moving hammer. The dissipation was estimated through a CFD analysis. The computed dissipated energy was less than 1.2% compared to the potential energy of the hammer with the given gap. Subsequently, the impact energy of the underwater SPT equipment was within 1.2% of that for the SPT equipment on land.

• 전기학회논문지
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• 제67권6호
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• pp.724-729
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• 2018

This paper presented an evaluation method for the efficiency uncertainty of an inverter-fed three-phase induction motor using FEM. The motor efficiency in the FEM is calculated by the IEC 60034-2-3 as in the actual test. In the process of evaluating the efficiency uncertainty, the difference between the finite element method and the actual test is the method of calculating the type-A / B standard uncertainty of the input quantity to estimate the efficiency and each losses. For the input quantities which can confirm the instantaneous values with respect to time, the type-A standard uncertainty in the FEM is calculated from the RMS values or average values having separate periods in the steady state. And, the type-B standard uncertainty in the finite element method is assumed to be zero. Also, this paper compared and analyzed the efficiency uncertainty evaluated by the proposed method and the efficiency uncertainty through the actual test.

• 한국군사과학기술학회지
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• 제25권3호
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• pp.311-320
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• 2022

In this paper, we studied the optimal method of improving performance for aircraft having various variants within the same type. The study defined configuration of an entire fleet of aircraft being subject to a performance improvement program. And selected the most complicated aircraft configuration among them as a Standard Aircraft for modification by according to the proposed Aircraft Selection Process for developing an optimal Aircraft Performance Improvement Process. Based on the selected the Standard Aircraft, drew a system integration design result and carried out Evaluation Test and obtained Airworthiness Certification. Created the database with the design data of the Standard Aircraft, Evaluation Test, and Airworthiness Certification results, and applied it to variants of aircraft to complete the performance improvement program with optimized schedules and costs. By applying the proposed method to IFF performance improvement program, drew optimal system integration design and completed the program with minimized schedule.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권2호
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• pp.140-144
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• 2009

테스트 주도 개발의 장점을 얻기 위해서는 효율적인 테스트 도구의 사용은 필수적이다. 기존의 통합 자동화 테스트 도구는 표준화 되지 않은 스크립트(script) 언어를 사용하거나 단위 테스트에 적합하지 않은 경우가 많다. 기존의 단위 테스트 도구는 대부분 프로그램의 원시코드에 테스트를 위한 코드가 추가된다. 이것은 원시 코드의 복잡도를 높이고 테스트 케이스 변경 시 원시코드의 여러 부분을 수정해야 하는 문제점이 있다. 본 논문에서는 테스트 주도 개발 시 개발자가 표준 자바 스크립트(Java script)를 이용하여 테스트 케이스 수정을 용이하게 할 수 있도록 유연한 테스트 도구의 설계를 제안하고 제안된 설계의 가용성을 검증하고자 테스트 도구를 구현하였다.