• 환경생물
• /
• 제38권4호
• /
• pp.507-517
• /
• 2020

본 연구에서는 외부형태적으로 매우 비슷한 참조기(Larimichthys polyactis) 와 부세(L. crocea)의 두 종 간 구분을 위해 계측형질 분석을 포함한 몇가지 기법들을 수행하였다. 총 48개의 계측형질 중 4개의 유의한 차이를 보이는 계측형질이 파악되었으며(p<0.05) classical dimension에서는 유의한 차이를 보이는 계측형질은 없었다(p>0.05). 오히려, 2가지의 truss dimension(Insertion of dorsal fin base origin of pectoral fin base와 Origin of anal fin base - origin of pectoral fin base)와 2가지의 head part dimension (Most anterior extension of the head - above of eye와 Above of eye posterior aspect of operculum)에서는 유의한 차이가 나타났다(p<0.05). 하지만, 이러한 4가지 계측형질 중 head part dimension의 Above of eye - posterior aspect of operculum의 계측형질을 제외한 나머지 3가지 계측형질들에서 부세가 참조기에 비해 더 큰 수치를 나타내었다(p<0.05). X-ray 분석 결과 curved vertebral column에서 부세는 45.1±2.34°로 참조기의 38.4±1.82°에 비해 8.4% 더 큰 수치를 나타내었다(p<0.05). 머리부위의 표피를 제거한 후의 유상돌기는 두 종에 모두 존재하여 일반적으로 참조기에서만 유상돌기가 존재한다고 알려진 바와는 달리, 유상돌기는 두 종을 구분하기 위한 형질로 볼 수 없었다. 본 연구 결과는 참조기와 부세에서 일부 외부 체형에 의해 명확히 구분 가능함을 시사한다.

• Structural Monitoring and Maintenance
• /
• 제3권4호
• /
• pp.315-333
• /
• 2016

This study aims to perform damage identification for Da-Sheng-Guan (DSG) high-speed railway truss arch bridge using fuzzy clustering analysis. Firstly, structural health monitoring (SHM) system is established for the DSG Bridge. Long-term field monitoring strain data in 8 different cases caused by high-speed trains are taken as classification reference for other unknown cases. And finite element model (FEM) of DSG Bridge is established to simulate damage cases of the bridge. Then, effectiveness of one fuzzy clustering analysis method named transitive closure method and FEM results are verified using the monitoring strain data. Three standardization methods at the first step of fuzzy clustering transitive closure method are compared: extreme difference method, maximum method and non-standard method. At last, the fuzzy clustering method is taken to identify damage with different degrees and different locations. The results show that: non-standard method is the best for the data with the same dimension at the first step of fuzzy clustering analysis. Clustering result is the best when 8 carriage and 16 carriage train in the same line are in a category. For DSG Bridge, the damage is identified when the strain mode change caused by damage is more significant than it caused by different carriages. The corresponding critical damage degree called damage threshold varies with damage location and reduces with the increase of damage locations.

• 한국발생생물학회지:발생과생식
• /
• 제21권1호
• /
• pp.55-62
• /
• 2017

We used flowcytometry to ploidy verification after that investigate difference between diploid and spontaneous triploid through the truss dimension and classical dimension at crucian carp, Carassius auratus, crucian carp C. cuvieri and common carp, Cyprinus carpio collected from Hangang river, Hantangang river, Imjingang river, Geumgang river, Yeongsangang river and Nakdonggang river, Korea. There were significant differences among the three species for the truss dimensions anterior origin of dorsal fin $(2){\times}$ anterior origin of anal fin (5), $2{\times}$ anterior origin of pelvic fin (6), $2{\times}$ origin of pectoral fin (7), posterior origin of dorsal fin $(3){\times}5$, $3{\times}6$, and $3{\times}7$ (P<0.05). There were no significant differences among the three species in the truss dimensions dorsal fin length ($2{\times}9$) and eye diameter (ED)(P>0.05). On the other hand, there were no significant differences in the several classical dimensions of each species (P>0.05). Three classical dimensions, most anterior extension of the head $(1){\times}2$, $1{\times}6$ and $2{\times}$ most posterior scale in lateral line (4) did not differ between the C. auratus diploid and spontaneous triploid (P>0.05). Two classical dimensions, $1{\times}6$ and longest length between most anterior extension of the head and gill cover ($1{\times}8$) did not differ between the C. cuvieri diploid and spontaneous triploid (P>0.05). One classical dimensions, $1{\times}2$ did not differ between the common carp diploid and spontaneous triploid (P>0.05). There were significant differences in the each diploid and triploid species (P<0.05). These results suggest that the classification of each species and classification between diploid and spontaneous triploid morphometrical parameters used in this study are useful indices of morphometrical status in the each species from major river of Korea.

• 한국발생생물학회지:발생과생식
• /
• 제18권1호
• /
• pp.33-41
• /
• 2014

We investigated the process of yolk absorption in Korean rose bitterling, Rhodeus uyekii, and determined the changes in its morphometric characteristics. The R. uyekii from 1 days post hatching (DPH) to 21 DPH, the eye diameter (ED) was 5.4 at 5 DPH. Thereafter, the ED/total length (TL) ratio increased to 10.7 at 21 DPH (p<0.05). The yolk length (YL) decreased from 95.4 to 1.1 by 21 DPH, and this rate of decrease was greater than that for any other dimension (p<0.05). 12 morphometric dimensions/TL for the R. uyekii were measured at each sampling day from 21 DPH to 170 DPH. At just hatching, the average TL and BW were $6.1{\pm}0.09mm$ and $4.9{\pm}0.07mg$, respectively. At 53 DPH, the average TL was $12.9{\pm}0.28mm$ and the average BW was $14.7{\pm}0.72mg$; the total length growth equation was $TL=5.507e^{0.038t}$ ($R^2=0.916$). Further, the body weight growth equation was $BW=3.3647e^{0.0296t}$ ($R^2=0.9354$). The dimensions with regard to body depth showed the greatest growth rates in the external characteristics of the fish (p<0.05). The patterns of the morphometric characteristics measured in this study can be classified in three ways. The patterns were shown to be increased (y=0.0992x+12.07, $R^2=0.8333$), decreased (y=-0.0569x+42.029, $R^2=0.8395$) or maintained (y=0.005x+18.263, $R^2=0.3678$) from 21 DPH to 170. These results will provide useful indices for the successful rearing of the R. uyekii.

• Structural Engineering and Mechanics
• /
• 제8권6호
• /
• pp.579-589
• /
• 1999

A new way to reduce the eigenvalue computation effort in structural dynamics is presented in this paper. The degrees of freedom of a structure may be classified into groups that are termed as sub-degrees of freedom. The eigenvalue analysis is performed with each of sub-degrees of freedom so that the computing time is much shortened. Since the dynamic coupling between sub-degrees of freedom is selected to be small and it may be considered as a perturbation, the perturbation algorithm is used to obtain an accuratae result. The accuracy of perturbation depends on the coupling between sub-degrees of freedom. The weaker the coupling is, the more accurate the result is. The procedure can be used to simplify a problem of three dimensions to that of two dimensions or from two dimensions to one dimension. The application to a truss and a space frame is shown in the paper.

• Smart Structures and Systems
• /
• 제30권6호
• /
• pp.673-686
• /
• 2022

Deep learning algorithms for Structural Health Monitoring (SHM) have been extracting the interest of researchers and engineers. These algorithms commonly used loss functions and evaluation indices like the mean square error (MSE) which were not originally designed for SHM problems. An updated loss function which was specifically constructed for deep-learning-based structural damage detection problems has been proposed in this study. By tuning the coefficients of the loss function, the weights for damage localization and quantification can be adapted to the real situation and the deep learning network can avoid unnecessary iterations on damage localization and focus on the damage severity identification. To prove efficiency of the proposed method, structural damage detection using convolutional neural networks (CNNs) was conducted on a truss bridge model. Results showed that the validation curve with the updated loss function converged faster than the traditional MSE. Data augmentation was conducted to improve the anti-noise ability of the proposed method. For reducing the training time, the normalized modal strain energy change (NMSEC) was extracted, and the principal component analysis (PCA) was adopted for dimension reduction. The results showed that the training time was reduced by 90% and the damage identification accuracy could also have a slight increase. Furthermore, the effect of different modes and elements on the training dataset was also analyzed. The proposed method could greatly improve the performance for structural damage detection on both the training time and detection accuracy.

• 한국어류학회지
• /
• 제24권3호
• /
• pp.151-159
• /
• 2012

정교배체인 각시붕어, Rhodeus uyekii (♀)${\times}$떡납줄갱이, R. notatus (♂) 잡종, 그리고 상반교배체인 떡납줄갱이 (♀)${\times}$각시붕어(♂) 잡종을 대상으로 혈액도말을 통한 적혈구 크기, flowcytometry를 통한 세포유전학적인 형질 및 truss dimension과 classical dimension에 의한 외부 계측형질에서의 특성을 부모종간의 차이를 비교하였다. 각시붕어와 떡납줄갱이의 정교배체 및 상반교배체의 계측형질은 일반적으로 이들 유도시 사용된 모계와 부계 종의 중간을 보였다. 정교배체는 14개의 계측형질이 부계의 형질과 유사하였으며 7개의 계측형질이 모계의 형질과 유사하였다. 상반교배체의 경우, 13개의 계측형질이 부계의 형질을, 5개의 계측형질이 모계의 형질과 유사하였다. 정교배체와 상반교배체의 체색소 분포는 중간을 보이나 양친 종을 닮게 나타났다(P<0.05). 적혈구 크기와 DNA 함량은 정교배체와 상반교배체 모두 모계의 적혈구 크기 및 DNA 함량을 따르는 경향이 나타났다(P<0.05). 본 연구에서 파악된 각시붕어와 떡납줄갱이의 잡종 계측형질 및 세포유전학적인 형질은 납자루아과의 관상어 개발시 종간 구별에 유용할 것이다.

• Smart Structures and Systems
• /
• 제25권3호
• /
• pp.345-368
• /
• 2020

The present work proposes a self-controlled multi-stage optimization method for damage identification of structures utilizing standard particle swarm optimization (PSO) algorithm. Damage identification problem is formulated as an inverse optimization problem where damage severity in each element of the structure is considered as optimization variables. An efficient objective function is formed using the first few frequencies and mode shapes of the structure. This objective function is minimized by a self-controlled multi-stage strategy to identify and quantify the damage extent of the structural members. In the first stage, standard PSO is utilized to get an initial solution to the problem. Subsequently, the algorithm identifies the most damage-prone elements of the structure using an adaptable threshold value of damage severity. These identified elements are included in the search space of the standard PSO at the next stage. Thus, the algorithm reduces the dimension of the search space and subsequently increases the accuracy of damage prediction with a considerable reduction in computational cost. The efficiency of the proposed method is investigated and compared with available results through three numerical examples considering both with and without noise. The obtained results demonstrate the accuracy of the present method can accurately estimate the location and severity of multi-damage cases in the structural systems with less computational cost.

• Steel and Composite Structures
• /
• 제18권2호
• /
• pp.289-303
• /
• 2015

This study presents a strategy so-called Subspace Search Mechanism (SSM) for reducing the computational time for convergence of population based metaheusristic algorithms. The selected metaheuristic for this study is the Cuckoo Search algorithm (CS) dealing with size optimization of trusses. The complexity of structural optimization problems can be partially due to the presence of high-dimensional design variables. SSM approach aims to reduce dimension of the problem. Design variables are categorized to predefined groups (subspaces). SSM focuses on the multiple use of the metaheuristic at hand for each subspace. Optimizer updates the design variables for each subspace independently. Updating rules require candidate designs evaluation. Each candidate design is the assemblage of responsible set of design variables that define the subspace of interest. SSM is incorporated to the Cuckoo Search algorithm for size optimizing of three small, moderate and large space trusses. Optimization results indicate that SSM enables the CS to work with less number of population (42%), as a result reducing the time of convergence, in exchange for some accuracy (1.5%). It is shown that the loss of accuracy can be lessened with increasing the order of complexity. This suggests its applicability to other algorithms and other complex finite element-based engineering design problems.

• Current Optics and Photonics
• /
• 제7권4호
• /
• pp.419-427
• /
• 2023

The structural design of an optical-telescope assembly (OTA) for satellite laser ranging (SLR) is conducted in two steps. First, the results of a parametric study of the major design variables (e.g. dimension and shape) of the OTA part are explained, and the detailed structural design of the OTA is derived, considering the design requirements. Among the structural-shape concepts of various OTAs, the Serrurier truss concept is selected in this study, and the collimation of the telescope according to the design variables is extensively discussed. After generating finite-element models for different structural shapes, self-gravity analyses are performed. To minimize the deflection and tilt of the mirror and frame for the OTA under the limited design requirements, a parametric study is conducted according to design variables such as the shapes of the upper and lower struts and the spider vane. The structural features found in the parametric study are described. Finally, the OTA structure is designed in detail to maintain the optical alignment by balancing the gravity deflections of the upper and lower trusses using the optimal combination of the parameters. Additionally, thermal analysis of the optical telescope design is evaluated.