• 설비공학논문집
• /
• 제29권12호
• /
• pp.645-653
• /
• 2017

Thermal and flow modeling and fin structure optimization were performed to reduce the weight of an electrical device with a staggered fin. First, a numerical model for thermal and flow characteristics was suggested, and then, the model was verified experimentally. Using the verified model, improvement in cooling performance of the cooling system through the staggered fins was predicted. As a result, 87.5% of total heat generated was dissipated through the cooling fins, and a thermal island was observed in the rotor because of low velocity of the internal air flow through the air gap. In addition, it was confirmed that the staggered fin improves the cooling performance but it also increases the total pressure drop within the cooling system, by maximizing the leading edge effect. Based on this analysis result, the effect of each design parameter on the thermal and flow characteristics was analyzed to select the main optimal design parameters, and multi-objective optimization was performed by considering the cooling performance and the fin weight. In conclusion, the optimized fin structure improved the cooling performance by 7% and reduced the fin weight by 28% without any compromise of the pressure drop.

• 항공우주시스템공학회지
• /
• 제9권4호
• /
• pp.31-36
• /
• 2015

The fatigue analysis for cutout panel used for the weight reduction of aircraft has been conventionally performed through the open hole concept using the reference stress and stress concentration factor (Kt). However, in the actual structure cases, the goal of weight reduction might be less meaningful due to the conservative approach induced by the difficulties of extracting the confident reference stress from FE-Analysis in the complicated loading behavior. Therefore a new approach is proposed in order to secure the effectiveness of weight reduction and validate the confidence of the analysis results using the interaction of max-min principal stress at the critical location of open hole edge line.

• 한국발생생물학회지:발생과생식
• /
• 제25권1호
• /
• pp.67-72
• /
• 2021

This study investigated the IGF-1 signal in specific tissues using Pacific oysters artificially matured via water temperature elevation. Pacific oysters were subjected to water temperature elevation from March to June, and 20 were randomly sampled each month. The condition index (CI) and tissue weight rate (TWR) were examined by measuring shell length, shell height, shell width, and soft tissue weight. The IGF-1 signal in tissues (adductor muscle, digestive glands, gills, labial palps, mantle edges, and gonads) was analyzed by sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. From April to June, the TWR of females and males increased from 19.1±2.9 to 21.0±3.6 and 18.2±2.0 to 19.2±2.5, respectively, while the CI remained the same. The IGF-1 signal in each tissue differed. IGF-1 was expressed in the adductor muscle, while tyrosine was expressed in all tissues. The phosphor (p)-ERK and p-AKT activities were high in the adductor muscle, mantle edge, and gonads. IGF-1 signaling affected the growth and maturity of the Pacific oysters examined.

• Journal of Ecology and Environment
• /
• 제37권4호
• /
• pp.201-208
• /
• 2014

To date, no study has reported detailed morphological characteristics of Korean sea turtles. Due to the lack of such basic information on Korean sea turtles, further related studies have been difficult in South Korea. In this report, we determined the species and the sex of the one sea turtle caught from the Yellow Sea of Korea (Taean-gun, Chungcheongnamdo) on July 17, 2013, and described its detailed morphological characteristics. The sea turtle was identified as a loggerhead sea turtle (Caretta caretta) by the presence of an interprefrontal scale on the head. The turtle had three times longer length between the edge of anal scute to the anus than that between the anus to tip of the tail, and the size of a pair of claws on the flippers were distinctively different, suggesting that the turtle was a male. Finally, the assumption that the sea turtle might be sexually mature is based on its body weight (59.95 kg), the maximum straight length of the carapace (72.5 cm), and the worn serrated parts at the edge of supracaudal scutes. The loggerhead sea turtle described in this study is the first record from the Yellow Sea of Korea.

• 한국안전학회지
• /
• 제29권5호
• /
• pp.15-21
• /
• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제37권11호
• /
• pp.866-870
• /
• 2010

본 논문에서는 근접 에지라는 새로운 에너지 항을 추가한 개선된 스네이크 알고리즘을 제안한다. 제안된 알고리즘은 스네이크 셀 주위에 근접하는 에지가 있을 경우 이 에지와 스네이크 셀 간의 거리를 에너지로 나타내고, 이 에너지를 전체 에너지 함수에 포함시킴으로써 물체의 윤곽선 탐색을 보다 효과적으로 수행한다. 근접 에지 기반의 스네이크 알고리즘은 셀이 물체의 오목한 경계 부분으로 탐색하는 것을 가능하게 하며, 에너지 항 사이에 실험적인 가중치 조정을 거치지 않고도 복잡한 물체의 윤곽선을 강인하게 검출할 수 있다. 제안된 방법의 성능 평가를 위한 실험에서는 개선된 스네이크 알고리즘이 속도를 크게 저하시키지 않으면서 윤곽선 추출의 정확도를 보다 개선하였음을 확인할 수 있었다.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 춘계학술대회 논문집
• /
• pp.100-107
• /
• 2001

One major problem in the model testing is the boundary effect and size effect caused by the limit in the size of the container. To overcome this problem, various types of laminar boxes are gradually manufactured and used in the shaking table test, which ideally has zero stiffness to horizontal shear. In this study, a small-scale laminar box is manufactured, which is composed of 6 thin aluminum rectangular hollow plates, and its inside dimensions are 300 mm length by 200 mm width by 350 mm depth. Shaking table tests are performed both with the laminar box and the rigid box under the same conditions, where displacements and accelerations are measured at various points of the box and model ground. As result of analyzing the measured data, during the propagation of input seismic motion from the bottom to the ground surface, the relative displacement of the model ground and the amplification of acceleration is hardly amplified in the rigid box. Because of the effect of stress waves reflecting from the rigid wall, the acceleration is slightly decreased at the edge in the rigid box. The laminar box, manufactured in this study, has a problem in that the soil behavior at the edge of ground surface is affected by the inertia force of the top layer due to its excessive self-weight.

• Computers and Concrete
• /
• 제22권1호
• /
• pp.71-81
• /
• 2018

Introduction of prestressed concrete slabs based on post-tensioned (PT) method aids in constructing larger spans, more useful floor height, and reduces the total weight of the building. In the present paper, for the first time, simulation of 32 two-way PT slab-edge column connections is performed and verified by some existing experimental results which show good consistency. Finite element method is used to assess the performance of bonded and unbonded slab-column connections and the impact of different parameters on these connections. Parameters such as strand bonding conditions, presence or absence of a shear cap in the area of slab-column connection and the changes of concrete compressive strength are implied in the modeling. The results indicate that the addition of a shear cap increases the flexural capacity, further increases the shear strength and converts the failure mode of connections from shear rigidity to flexural ductility. Besides, the reduction of concrete compressive strength decreases the flexural capacity, further reduces the shear strength of connections and converts the failure mode of connections from flexural ductility to shear rigidity. Comparing the effect of high concrete compressive strengths versus the addition of a shear cap, shows that the latter increases the shear capacity more significantly.

• 한국콘텐츠학회논문지
• /
• 제16권7호
• /
• pp.431-438
• /
• 2016

본 논문은 색상정보와 깊이정보 가중치를 이용한 깊이영상 업샘플링 방법을 제안한다. 제안하는 알고리즘은 먼저 양선형 보간법을 통해 높은 해상도의 깊이영상을 생성한다. 그 후 RGB 색상영상, HSV 색상영상, 깊이영상 등을 이용하여 공통경계 영역을 추정한다. 만일 보간 된 화소가 공통경계 영역에 속한다면 해당화소를 포함하는 $3{\times}3$ 영역의 화소들에 대한 색상정보와 깊이정보의 가중치를 구하고 경계 화소값 결정을 위한 비용계산을 수행한다. 그 후 가장 작은 경계 화소값 결정 비용을 가지는 화소 값을 결과영상의 화소값으로 정한다. 제안하는 알고리즘은 PSNR 및 주관적 화질 비교에서 우수한 성능을 보였다.

• 한국정보통신학회논문지
• /
• 제16권3호
• /
• pp.598-604
• /
• 2012

영상신호는 신호를 처리하는 과정에서 다양한 잡음에 의해 훼손되어지며, 이러한 신호를 복원하기 위한 많은 연구가 이루어지고 있다. 본 논문에서는 랜덤 임펄스 잡음을 제거하기 위한 캐스케이드 필터 알고리즘을 제안하였다. 알고리즘은 잡음검출과 잡음제거 등 두 과정으로 구성되었으며, 잡음검출을 위하여 마스크의 분산과 중앙화소에 의한 분산을 이용하였다. 또한, 잡음신호에 대해서 스위칭 self adaptive weighted median 필터로 처리한 후, 변형된 가중치 알고리즘을 적용하여 제거하였다. 제안한 알고리즘은 잡음신호만을 제거하고 비잡음신호는 그대로 보존하여, 우수한 에지 보존특성 및 잡음제거 능력을 나타내었다.