• Title, Summary, Keyword: 물보라

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Study on scoring system of fire from warships (함정 사격 채점 시스템에 관한 연구)

  • Kim, Dong-Il
    • Proceedings of the Korean Society of Computer Information Conference
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    • pp.339-340
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    • 2016
  • 함정 함포 사격 채점은 사격함에서 발사한 탄을 타겟을 예인하고 있는 함정에서 관찰하여 이루어 진다. 채점은 함정을 운용하는 승조원의 기량 평가와 관련 있기 때문에 공정성이 중요하다. 명중 여부는 타겟 주위에 발생하는 물보라를 관측하여 결정하는데, 물보라의 경우 사격 이후 수 초 내에 없어져서 예인함의 인원이 육안으로만 관찰해서는 공정한 채점을 할 수 없다. 캠코더등의 영상기록장치를 이용하여 사격을 기록하고 컴퓨터비전을 활용하여 채점의 공정성을 높일 수 있다. 본 논문에서는 컴퓨터 시스템을 활용하여 함정 사격 채점 시스템을 구현할 때 시스템이 갖추어야 할 기능과 컴퓨터비젼의 활용방법 및 함정에 설치되어 있는 전투체계 시스템을 활용하는 방법에 대하여 알아보고 실제로 시스템을 구현해 본다.

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부산광역시에 대한 입자상 물질의 건성침적속도 수치 모의

  • 반수진;이황운;문난경
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • pp.35-37
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    • 2001
  • 입자상 물질에 대한 건성침적속도를 구하는 두 가지 모형 중 Slinn의 모수화로 구축된 건성침적모형이 ADOM 건성침적모형에 비해 좀 더 신뢰성있는 결과를 산출하였고 부산광역시에서의 입자상 물질에 대한 건성침적속도 수치모의 결과도 전반적으로 거칠기 길이가 큰 산림지역에서 높은 값이 나타남을 보여주었다. 입자상 물질의 건성침적속도 계산에 있어 가장 중요한 것은 대상 입자의 크기이므로 무엇보다도 그 물질에 대한 정확한 크기분포에 대한 규명이 있어야 하고 또한 본 연구에서는 다루지 못한 수면의 높은 풍속에서의 물결 파괴, 물보라 형성 그리고 물과 공기경계면 근처의 습한 지역에서 입자 성장의 영향 등을 고려하는 좀더 자세한 연구가 추후에 이루어져야 할 것이다.

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Numerical Analysis of Nonlinear Shoaling Characteristics over Surf Zone Using SPH and Lagrangian Dynamic Smagronsky Model (Lagrangian Dynamic Smagronsky 난류모형과 SPH를 이용한 쇄파역에서의 비선형 천수거동에 관한 연구)

  • Cho, Yong-Jun;Lee, Heon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.1
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    • pp.81-96
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    • 2007
  • Nonlinear shoaling characteristics over surf zone are numerically investigated based on spatially averaged NavierStokes equation. We also test the validity of gradient model for turbulent stresses due to wave breaking using the data acquainted during SUPERTANK LABORATORY DATA COLLECTION PROJECT(Krauss et al., 1992). It turns out that the characteristics length scale of breaking induced current is not negligible, which firmly stands against ever popular gradient model, ${\kappa}-{\varepsilon}$ model, but favors Large Eddy Simulation with finer grid. Based on these observations, we model the residual stress of spatially averaged NavierStokes equation after Lagrangian Dynamic Smagorinsky(Meneveau et al., 1996). We numerically integrate newly proposed wave equations using SPH with Gaussian kernel function. Severely deformed water surface profile, free falling water particle, queuing splash after landing of water particle on the free surface and wave finger due to structured vortex on rear side of wave crest(Narayanaswamy and Dalrymple, 2002) are successfully duplicated in the numerical simulation of wave propagation over uniform slope beach, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.

Suspension of Sediment over Swash Zone (Swash대역에서의 해빈표사 부유거동에 관한 연구)

  • Cho, Yong Jun;Kim, Kwon Soo;Ryu, Ha Sang
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.1B
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    • pp.95-109
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    • 2008
  • We numerically analyzed the nonlinear shoaling, a plunging breaker and its accompanying energetic suspension of sediment at a bed, and a redistribution of suspended sediments by a down rush of preceding waves and the following plunger using SPH with a Gaussian kernel function, Lagrangian Dynamic Smagorinsky model (LDS), Van Rijn's pick up function. In that process, we came to the conclusion that the conventional model for the tractive force at a bottom like a quadratic law can not accurately describe the rapidly accelerating flow over a swash zone, and propose new methodology to accurately estimate the bottom tractive force. Using newly proposed wave model in this study, we can successfully duplicate severely deformed water surface profile, free falling water particles, a queuing splash after the landing of water particles on the free surface and a wave finger due to the structured vortex on a rear side of wave crest (Narayanaswamy and Dalrymple, 2002), a circulation of suspended sediments over a swash zone, net transfer of sediments clouds suspended over a swash zone toward the offshore, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.

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A Study on the Hull Form Design of Semi-Planing Round-Bilge Craft (Round-Bilge 고속 반활주선의 선형특성 및 설계에 관한 연구)

  • Lee, Jung-Gwan;Jung, Kwang-Hyo;Suh, Sung-Bu;Chun, Ho-Hwan;Lee, In-Won
    • Journal of Ocean Engineering and Technology
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    • v.24 no.4
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    • pp.59-65
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    • 2010
  • This study presents the design procedure for optimizing the semi-planing hull form, including appendages, using numerical and experimental methods. Four different referenced semi-planing hull forms were compared to determine their hydrodynamic performances, and one of the hull forms was modified for optimum operation at high-speed conditions (0.4 < $F_{NL}$ < 0.9). The optimized, semi-planing hull form was tested in the towing tank to investigate its resistance characteristics. Also, the results of the model tests with differing design parameters were used to choose the stern wedge and the spray strip to improve the hydrodynamic performance at high speeds.

The Estimation of Surface Chloride Content and Durability of the Marine Concrete Bridges in South Coast (남해안 해상 콘크리트 교량의 표면염화물이온농도 및 내구성 평가)

  • Jung, Dae-Jin;Choi, Ik-Chang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.6
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    • pp.730-737
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    • 2014
  • In this study, chloride content of marine concrete bridge at the south coast in 5~34years was calculated based on the measured data and the validity of the proposed value was evaluated. Also, correlation of existence of salt injury prevention coating, chloride content, carbonation depth and the compressive strength of marine concrete bridges were derived and relationship of the four was evaluated. According to the research results, surface chloride content value in the tidal zone proposed form KCI 2009 and value in the splash zone and atmospheric zone proposed form Cheong et al.(2005) was the most valid. Also, salt injury prevention coating of marine concrete bridges had the outstanding effect of preventing chloride content penetration, carbonation depth and reduction in the compressive strength. Compressive strength of concrete was reduced by the increase of carbonation depth and chloride content.

'The Same Scenery' and 'a Different Landscape' Included in "Real-Scenery Landscape Painting", an Essay to Determine Meaning - Centering around Paintings of Chong Seok Jeong in the 18th-19th Centuries - (실경산수화에 담긴 '같은 경관' 그러나 '다른 풍경', 그 의미 찾기 - 18.19C 총석정 그림을 중심으로 -)

  • Rho, Jae-Hyun;Jang, Il-Young
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.5
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    • pp.82-93
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    • 2008
  • This research focused on the process in which 'the same scenery' is recognized and represented as 'a different landscape' to determine the symbols and meaning of the scenery and landscape included in real-scenery landscape paintings of the 18th-19th centuries. As a result of analyzing the visual points, the content and expressions of 25 real-scenery landscape paintings of Chong Seok Jeong(叢石亭), it can be seen that the transmission of a kind of semiotic landscape on the basis of a specific symbol was accomplished naturally through imitation and representation for the purpose of the expression of Chong Seok Jeong-like idealized scenery. This shows that the unique images of Chong Seok Jeong have long been passed down after taking root as a unique benchmark The meaningful symbol of 'a strange Saseonbong(四仙峰)', which is broken by the spray after rising high, and 'a pine forest' have both been transmitted as being in the manner of Chong Seok Jeong. This has been equipped with the stereo-type scene by being a collective symbolization as the psycho-scenes in memory element of Chong Seok Jeong. Through the pictures of both Gyeomjae(謙齋) and Danweon(檀園), the process by which a specific painter's pictures become acculturated is highly interesting. The scenery expressed in these pictures was clearly that of a landscape of which its particularly emotions and remembrances were repainted through the experience of several places and original sketches. This can be explained as the concept in which the image from 'a specific scenery' gained through actual experience, that is, a personal feeling, has been expressed. The picture that was expressed as a different figure even at the same visual point for the same scenery is the result that was redefined through the scenery subject's recognition. Also, the modification of the scenery object can be colorful through meditation and Sachu(邪推: guessing with wicked doubt). The scenery recognized newly through adoption, omission and emphasis, it is 'the specific scenery' in the heart and is a figure having been more similar to 'a landscape' if the objective life reproduction before being acculturated is a figure similar to the scenery. So, the concept looks like being very persuasive that 'the nature with objectivity captured sensuously' simply is the scenery, and that 'the subjective phenomenon having acquired the cultural nature by being introspected in the method of aesthetic nostalgia is a landscape'.