• 천문학회지
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• 제29권spc1호
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• pp.85-86
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• 1996

The imaging spectroscopic observations of the Magellanic irregular galaxy NGC 4449 were made to show the detailed kinematic structure of the galaxy. Many filamentary structures and Several bubble-like structures are recognized in a 3D data cube of H$\alpha$ emission line. Velocity field shows the kpc-scale mosaic structure and counter- rotation of ionized gas.

• Structural Engineering and Mechanics
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• 제67권5호
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• pp.457-464
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• 2018

This paper presents a method for detecting damage in irregular 2D and 3D continuum structures based on combination of wavelet transform (WT) with fuzzy inference system (FIS) and particle swarm optimization (PSO). Many damage detection methods study regular structures. This method studies irregular structures and doesn't need response of healthy structures. First the damaged structure is analyzed with finite element methods, and damage response is obtained at the finite element points that have irregular distance, secondly the FIS, which is optimized by PSO is used to obtain responses at points, having equal distance by response at those points that previously obtained by the finite element methods. Then a 2D (for 2D continuum structures) or a 3D (for 3D continuum structures) matrix is performed by equal distance point response. Thirdly, by applying 2D or 3D wavelet transform on 2D or 3D matrix that previously obtained by FIS detail matrix coefficient of WT is obtained. It is shown that detail matrix coefficient can determine the damage zone of the structure by perturbation in the damaged area. In order to illustrate the capability of proposed method some examples are considered.

• Journal of Forest and Environmental Science
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• 제34권6호
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• pp.451-456
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• 2018

The use of single component distribution to describe the irregular stand structure of degraded forest often lead to bias. Such biasness can be overcome by the application of finite mixture distribution. Therefore, in this study, finite mixture distribution was used to characterise the irregular stand structure of the Gmelina arborea plantation in Omo forest reserve. Thirty plots, ten each from the three stands established in 1984, 1990 and 2005 were used. The data were pooled per stand and fitted. Four finite mixture distributions including normal mixture, lognormal mixture, gamma mixture and Weibull mixture were considered. The method of maximum likelihood was used to fit the finite mixture distributions to the data. Model assessment was based on negative loglikelihood value ($-{\Lambda}{\Lambda}$), Akaike information criterion (AIC), Bayesian information criterion (BIC) and root mean square error (RMSE). The results showed that the mixture distributions provide accurate and precise characterisation of the irregular diameter distribution of the degraded Gmelina arborea stands. The $-{\Lambda}{\Lambda}$, AIC, BIC and RMSE values ranged from -715.233 to -348.375, 703.926 to 1433.588, 718.598 to 1451.334 and 3.003 to 7.492, respectively. Their performances were relatively the same. This approach can be used to describe other irregular forest stand structures, especially the multi-species forest.

• 한국해양공학회지
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• 제25권4호
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• pp.1-6
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• 2011

The installation of a topside structure can be categorized into the following stages: start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the module onto the floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with a significant wave height (1.52m). The effects of the hydrodynamic interactions between the heavy lifting vessel and the spar hull during the lowering and mating stages are considered. The internal forces caused by the load transfer and ballasting are derived for the mating phases. The results of the internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of the pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the mating phases, the internal force induced pitch motion is too small to have this influence. However, the effect of the internal force on the wave-induced heave responses in the mating phases is noticeable in the irregular sea condition because transfer mass-induced draught changes for the floating structure are observed to have higher amplitudes than the external force induced responses. The impacts of the module on the spar hull in the mating phase are investigated.

• 한국안광학회지
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• 제1권1호
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• pp.15-22
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• 1996

본 연구는 망막조직의 미세구조를 전자현미경을 이용하여, 생쥐(ICR)에 대한 Laser 조사의 영향을 조사하였다. 그 결과는 다음과 같다. l. 정상군에서 대개의 망막층은 여러 특수한 세포들과 신경섬유로 구성된 복잡한 구조를 가지고 있었다. 2. Laser 조사의 기간이 길어질수록, 망막의 각 세포의 층과 구조는 일정한 형태를 나타내지 못했다. 시세포 visual cell들은 심하게 이형염색질체 heterochromatin이며, 세포질은 종대되며, 핵의 모양은 불규칙적이며,일부의 세포질은 소실되었다. 망막층의 핵과 신경섬유는 매우 불규칙적이며, 소포의 형성, 각 세포간 경계의 불명확함이 있었다. 색소상피세포 pigment epithelail cell들은 정상모양이 아니며, 세포질에는 큰 공포 형성이 있으며, 핵의 응축과 불규칙한 모양 등이 있었다.

• 한국CDE학회논문집
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• 제19권2호
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• pp.91-102
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• 2014

The outer surface of an irregular structure contains panels with two-directional curvature called NURBS. To construct these forms of exterior materials, complex geometric surface should be divided into forms and sizes that can be manufactured and constructed. Because the bigger the curvatures of these divided exterior panel, the more expensive the construction costs, these complex two-directional curvatures should go through optimal process of reinterpretation to minimize the curved surfaces with complex two-directional curvatures. Yet, to gain higher ground in technological competition in the field of irregular structure construction, companies do not share know-how that they obtained. Accordingly, small construction and design companies have trouble calculating even rough estimate and cannot adjust expected construction cost based on comparison of design alternatives. Given this situation, this study conducted the research that can support decision-making in the design stage of the construction and provide basic material for optimal range to reduce manufacturing cost by the minimizing the distorted plane of the irregular structure.

• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.73-79
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• 2004

파랑에 의해 발생하는 해양구조물의 진동을 억제하기 위해 동조질량감쇠기(Tuned Mass Damper, TMD)를 적용하여 그 효과를 분석하였다. 해양구조물의 운동방정식에 포함된 파랑-구조물 상호작용에 의한 비선형성을 선형화한 경우의 오차와 TMD설계시 선형방정식을 사용한 경우 발생할 수 있는 현상을 분석하였다. TMD설치 전후의 제진효과 분석에서는 주기를 달리한 규칙파에 의한 성능과, 유의파가 서로다른 불규칙파에 의한 성능을 동시에 분석하였다. 규칙파에 의한 해석결과 입사파의 주기가 구조물의 첫 번째 고유주기와 근접한 경우 제진효과가 뛰어났으며 주기가 더 짧거나 더 긴 경우는 제진효과가 감소하였다. 불규칙파에 의한 해석결과는 유의파가 상대적으로 작아 구조물의 고유주기 성분이 많이 포함된 파랑에 대한 제진효과가 뛰어나고, 유의파가 커서 구조물의 고유주기 보다 큰 성분이 많이 포함된 파랑에서는 제진효과를 발견할 수 없었다. 따라서, 해양구조물에 TMD를 적용할 때는 파고가 작은 상시 내습 파랑에 대한 제진효과를 볼 수 있으며 이는 상시 진동제어를 통한 피로수명 확보에 큰 도움이 될 것으로 예상된다.

• 한국도서관정보학회지
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• 제45권2호
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• pp.205-234
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• 2014

이 연구는 우리나라 학교도서관 비정규직 인력 문제에 대해 구조적인 관점으로 살펴보고 정리하였다. 비정규적 인력이 확대된 배경과 계기를 살펴보고 비정규직 인력의 직무상 주요 문제점들을 검토하였다. 그리고 비정규직 인력 문제의 표면과 이면의 내용과 구조를 체계적으로 탐구하여 문제의 성격과 내적 갈등 양상을 확인하였다. 이를 바탕으로 현재 제안되거나 진행되고 있는 비정규직 인력 문제의 해결 방안에 대해 점검하고 문제 해결을 위해 요청되는 기본적인 자세를 제안하였다.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.601-607
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• 2018

Median filtering is a nonlinear method which is known to be effective in removing impulse noise while preserving local image structure relatively well. However, it could still suffer the smearing phenomena of edges and fine details into neighbors due to undesirable influence from the pixels whose values are far off from the true value of the pixel at hand. This drawback mainly comes from the fact that median filters typically employ a regular shape window for collecting the pixels used in the filtering operation. In this paper, we propose a median filtering method which employs an irregular shape filter window in collecting neighboring pixels around the pixel to be denoised. By employing an irregular shape window, we can achieve good noise suppression while preserving image details. Experimental results have shown that our approach is superior to regular window-based methods.

• 한국ITS학회 논문지
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• 제9권5호
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• pp.87-95
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• 2010

도시의 많은 교량 구조물은 내구연한 및 노후 상태에 따라 외형적 변형이 발생하고, 지진과 태풍 등은 노후 시설물의 변형을 더욱 악화시키고 있다. 불규칙하고 미세한 점진적 외형 변형은 육안으로 확인하기 어렵고, 시설물의 성능을 저하시키게 된다. 따라서 최근에 교량 구조물의 이상 거동을 실시간의 무선 방식으로 검지하는 기술이 연구되고 있다. 본 연구는 자이로스코프를 이용하여 구조물의 미소한 물리적 변화량을 실시간으로 측정하는 변위측정모듈을 개발하였다. 개발된 계측 모듈의 성능은 시뮬레이션 실험을 통해 검증하였다.