• 제목/요약/키워드: Similarity Law

검색결과 144건 처리시간 0.02초

전투기급 비행제어법칙 상사성 및 HILS 환경 신뢰성 검증 (Verification of Flight Control Law Similarity and HILS Environment Reliability for Fighter Aircraft)

  • 안성준;김종섭;조인제;이은용
    • 한국항공우주학회지
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    • 제37권7호
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    • pp.701-708
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    • 2009
  • 개발된 비행제어컴퓨터(DFLCC: Developed Flight Control Computer)의 비행제어법칙은 고등훈련기급 항공기의 시제 최종 형상의 비행제어소프트웨어(OFP: Operation Flight Program)를 기반으로 개발되었다. 비행제어법칙은 상용 개발 툴을 이용하여 GUI(Graphic User Interface) 환경에서 설계되며, C 코드로 변환되어 OFP 에 반영된다. 그리고 OFP는 정형화된 검증절차를 통하여 검증되는데, 검증과정을 거치기 전에 비실시간 환경에서 C코드로 변환된 비행제어법칙과 기반이 되는 비행제어법칙의 상사성(similarity)을 검증하고, 구성된 HILS(Hardware In-the-Loop Simulator) 환경의 신뢰성(reliability)을 사전에 검증하는 절차가 필요하다. 비행제어법칙의 상사성은 비실시간 환경에서 고등훈련기급 항공기의 시제 최종 버전의 비행제어법칙과 개발된 비행제어법칙의 응답특성을 상호 비교하여 검증된다. 또한, 구성된 HILS 환경의 신뢰성은 비실시간 시뮬레이션 툴을 기반으로 HILS 결과와 항공기 응답특성을 비교하여 검증된다. 본 논문에서는 항공기 응답을 직접 비교함으로써 개발된 비행제어법칙의 상사성과 HILS 환경의 신뢰성을 검증하였다.

Experimental validation of simulating natural circulation of liquid metal using water

  • Lee, Min Ho;Jerng, Dong Wook;Bang, In Cheol
    • Nuclear Engineering and Technology
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    • 제52권9호
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    • pp.1963-1973
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    • 2020
  • Liquid metal-cooled reactors use various passive safety systems driven by natural circulation. Investigating these safety systems experimentally is more advantageous by using a simulant. Although numerous experimental approaches have been applied to natural circulation-driven passive safety systems using simulants, there has been no clear validation of the similarity law. To validate the similarity law experimentally, SINCRO-V experiment was conducted using Wood's metal and water for simulant of the Wood's metal. A pair of SINCRO-V facilities with length-scale ratio of 14.1:1 for identical Bo' was investigated, which was the main similarity parameter in temperature field simulation. In the experimental range of 0.2-1.0% of decay heat, the temperature distribution characteristics of the small water facility were very similar to that of the large Wood's metal facility. The temperature of the Wood's metal predicted by the water experiment showed good agreement with the actual Wood's metal temperature. Despite some error factors like discordance of Gr' and property change along the temperature, the water experiment predicted the Wood's metal temperature with an error of 27%. The validity of the similarity law was confirmed by the SINCRO-V experiments.

Study on Design of Air-water Two-phase Flow Centrifugal Pump Based on Similarity Law

  • Matsushita, Naoki;Furukawa, Akinori;Watanabe, Satoshi;Okuma, Kusuo
    • International Journal of Fluid Machinery and Systems
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    • 제2권2호
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    • pp.127-135
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    • 2009
  • A conventional centrifugal pump causes a drastic deterioration of air-water two-phase flow performances even at an air-water two-phase flow condition of inlet void fraction less than 10% in the range of relatively low water flow rate. Then we have developed a two-phase flow centrifugal pump which consists of a tandem arrangement of double rotating cascades and blades of outer cascade have higher outlet angle more than $90^{\circ}$. In design of the two-phase flow pump for various sized and operating conditions, similarity relations of geometric dimensions to hydraulic performances is very useful. The similarity relations of rotational speed, impeller diameter and blade height are investigated for the developed impeller in the present paper. As the results, the similarity law of rotational speed and impeller diameter is clarified experimentally even in two-phase flow condition. In addition, influences of blade height on air-water two-phase flow performances indicate a little difference from the similarity relations.

Application of two different similarity laws for the RVACS design

  • Min Ho Lee;Ji Hwan Hwang;Ki Hyun Choi;Dong Wook Jerng;In Cheol Bang
    • Nuclear Engineering and Technology
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    • 제54권12호
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    • pp.4759-4775
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    • 2022
  • The RVACS is a versatile and robust safety system driven by two natural circulations: in-vessel coolant and ex-vessel air. To observe interaction between the two natural circulations, SINCRO-IT facility was designed with two different similarity laws simultaneously. Bo' based similarity law was employed for the in-vessel, while Ishii's similarity law for the ex-vessel excluding the radiation. Compared to the prototype, the sodium and air system, SINCRO-IT was designed with Wood's metal and air, having 1:4 of the length reduction, and 1.68:1 of the time scale ratio. For the steady state, RV temperature limit was violated at 0.8% of the decay heat, while the sodium boiling was predicted at 1.3%. It showed good accordance with the system code, TRACE. For an arbitrary re-criticality scenario with RVACS solitary operation, sodium boiling was predicted at 25,100 s after power increase from 1.0 to 2.0%, while the system code showed 30,300. Maximum temperature discrepancy between the experiments and system code was 4.2%. The design and methodology were validated by the system code TRACE in terms of the convection, and simultaneously, the system code was validated against the simulating experiments SINCRO-IT. The validated RVACS model could be imported to further accident analysis.

한.일 중재법상 중재판정의 비교법적 고찰 (A Comparative Study Arbitral A ward under the Arbitral Laws between Korea and Japan)

  • 최석범;정재우;김태환
    • 한국중재학회지:중재연구
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    • 제16권1호
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    • pp.81-119
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    • 2006
  • The parties in the trade can have full autonomy and can resolve disputes independently, impartially and without delay by selecting arbitration by agreement. Korea and Japan had revised their Arbitration Laws to incorporate as many provisions of the 1985 UNCITRAL Model Law as possible. Japan had amended its century-old arbitration law, becoming the 45th country to adopt the UNCITRAL Model Law on International commercial arbitration. New Arbitration Law was enacted as Law No.138 of 2003 and effective on March 1, 2004, is applicable to both national and international arbitration. Korea had amended its arbitration law on December 31, 1999 and its New Arbitration Law incorporates the most of the 1985 UNCITRAL Model Law as Japan. Arbitration must be popular in resolving international commercial disputes in Northeast Asian bloc in order to increase the volume of intra-trade in the Northeast Asian bloc. But in order for the parties to make use of arbitration in the bloc, the arbitration laws of nations in the bloc must have similarity and unification. As Korea and Japan playes important roles in the bloc, both nations's arbitration laws must be studied in view of similarity and difference to unify both nations' arbitration laws by way of showing an example. Therefore, this paper deals with both nations' arbitration laws in view of comparative law to unify their arbitration laws and Northeast Asian Nations' arbitration laws.

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상사법칙을 이용한 수직발사 유도탄 추력곡선예측 (Thrust Profile Prediction for a Vertical Launching Missile using Similarity Law)

  • 조성진;김을곤;안조영
    • 한국항공우주학회지
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    • 제37권1호
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    • pp.55-61
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    • 2009
  • 본 논문은 검증된 수직발사 유도탄을 모델로 고려하여 개발하려는 수직발사 유도탄의 추력을 예측하는 방법을 제안한다. 개발하려는 수직발사 유도탄의 추력을 예측하기위해 모델에 상사법칙과 Pi 이론을 적용하였다. 검증된 수직발사 유도탄의 6-DOF 프로그램에 기반한 예측 결과와 개발하려는 수직발사 유도탄의 모의시험 결과를 비교하여 제안된 방법의 타당성을 검증하였다.

기하상사법을 이용한 대형 소음기의 성능평가에 관한 해석적 연구 (Analytical Study on Performance Evaluation of Large-Sized Silencer using Geometric Similarity Law)

  • 양준혁;이부윤;김원진
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권2호
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    • pp.275-281
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    • 2010
  • 선박용 엔진 또는 플랜트 시스템에 사용되는 대형 소음기의 개발단계에서 비용절감 및 개발기간의 단축을 위하여 축소모형으로 대체 실험이 가능하도록 기하상사법을 제안하고자 한다. 대형 소음기를 구성하고 있는 공명형과 단순 확장관형 소음기의 원형과 축소 모형에 대한 이론식으로부터 기하상사 변수를 규명하였다. 그리고 음향해석을 통하여 조합형과 배플형의 축소 모형에 기하상사법을 적용하여 원형모형의 성능을 예측하고, 이를 원형모형의 실제 성능과 비교하는 방법으로 기하상사 변수를 검증하였다.

원심모형시험기를 이용한 사면의 침투 및 파괴에 관한 상사법칙의 검토 (Similarity rule of Seepage failure by Centrifuge model test)

  • 김재영;동전순
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2004년도 춘계학술발표회
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    • pp.313-318
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    • 2004
  • 필 댐이나 제방의 침투에 의한 파괴현상을 원심모형실험으로 모사하는 경우, 지금까지는 물을 이용해 파괴시키는 원심모형실험이 실시되고 있었다. 그리고 점성유체를 사용한 원심모형실험도 실시되고 있지만, 상사법칙의 검증이 이루어지지 않은 상태에서의 실험결과에는 의문이 남아있다. 본 연구에서는, 물의 n배 점성용액을 사용해 상사법칙을 성립시켜 Modeling of Models의 방법에 따라 검증하였다.

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Evaluation of Similarity Analysis of Newspaper Article Using Natural Language Processing

  • Ayako Ohshiro;Takeo Okazaki;Takashi Kano;Shinichiro Ueda
    • International Journal of Computer Science & Network Security
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    • 제24권6호
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    • pp.1-7
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    • 2024
  • Comparing text features involves evaluating the "similarity" between texts. It is crucial to use appropriate similarity measures when comparing similarities. This study utilized various techniques to assess the similarities between newspaper articles, including deep learning and a previously proposed method: a combination of Pointwise Mutual Information (PMI) and Word Pair Matching (WPM), denoted as PMI+WPM. For performance comparison, law data from medical research in Japan were utilized as validation data in evaluating the PMI+WPM method. The distribution of similarities in text data varies depending on the evaluation technique and genre, as revealed by the comparative analysis. For newspaper data, non-deep learning methods demonstrated better similarity evaluation accuracy than deep learning methods. Additionally, evaluating similarities in law data is more challenging than in newspaper articles. Despite deep learning being the prevalent method for evaluating textual similarities, this study demonstrates that non-deep learning methods can be effective regarding Japanese-based texts.

Hack의 법칙과 집수평면의 기하학적 특성 (Hack's Law and the Geometric Properties of Catchment Plan-form)

  • 김주철;이상진
    • 한국수자원학회논문집
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    • 제42권9호
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    • pp.691-702
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    • 2009
  • 본 연구에서는 집수평면의 신장도에 대한 검토와 함께 자연유역의 자기유사성 및 자기상사성을 고려하여 Hack의 법칙에 대한 체계적인 접근을 수행하여 보았다. DEM으로부터 추출된 대상유역의 집수평면들은 Hack의 법칙에 대한 두 가설이 상호작용을 할 경우 나타날 수 있는 유역 형상들에 대한 모집단처럼 나타났다. 유역면적에 따른 집수평면 신장도의 변화를 도시해 본 결과 유로연장을 기반으로 한 고전적인 지형인자들보다는 관성적률을 기반으로 한 신장도가 보다 직관적인 결과를 줄 수 있을 것으로 판단되었다. Hack의 법칙에 대한 지수 h는 Gray (1951)의 연구결과와 유사하게 산정됨을 확인할 수 있었다. 하지만 대상유역들에 대한 Hurst의 지수 H는 0.96으로 나타나 본 연구에서 고려한 집수평면들은 규모에 따라 등방성 성장률을 가지고 있는 것으로 사료되었다. 이로부터 본 연구의 대상유역들의 형상은 집수평면의 자기유사성보다는 유로연장의 자기상사성에 더 영향을 받는 것으로 추론할 수 있었다.