• 항공우주시스템공학회지
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• 제16권6호
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• pp.24-34
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• 2022

본 연구에서는 우주 그물의 우주 물체 포획 성능을 향상시키기 위하여 충격 흡수의 이점을 가지는 거미집 구조의 생체 모방 우주 그물을 이용한 우주 물체 포획 시뮬레이션을 수행하였다. 포획 시뮬레이션은 비선형 구조 동역학 해석 프로그램인 ABAQUS를 이용하여 수행하였다. 우주 물체는 12U 크기의 CubeSat을 강체로 모델링하였다. 거미집 구조의 우주 그물은 대각선 길이가 2.828 m이며, 탄성보 요소를 이용하여 구현하였다. 동일 중량의 정사각형 우주 그물의 포획 시뮬레이션 결과와 비교하여 생체 모방 우주 그물의 포획의 우수성을 확인하였다. 또한, 거미집 구조의 우주 그물을 이용하여 우호적 및 비우호적으로 운동하는 우주 물체를 포획하는 수치 시뮬레이션을 수행하였으며, 우주 물체의 포획 성공 및 실패 사례를 조사하였다.

• Fisheries and Aquatic Sciences
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• 제25권4호
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• pp.214-230
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• 2022

Loss and damage have become a vital contemporary issue in climate change studies and actions in developing countries. However, studies are scant on this in the fisheries sector around the world. In Bangladesh, there is no study on the loss and damage in fisheries dependent communities. This study assesses economic and non-economic loss and damage to coastal shrimp farms due to cyclone Bulbul in Gabura Union of Shyamnagar Upazila, Satkhira district, using a mixed method approach. Results show that all shrimp farms' dependent communities are affected by cyclone Bulbul to some extent. About 14%, 57%, and 29% of the farms were totally, heavily and moderately damaged due to farm inundation and dyke damage. The estimated mean loss and damage per shrimp farm was worth USD 4,633. Around 31% and 72% of the farms' fencing nets and traps were lost, which was worth USD 333 per farm. There were also loss and damage to other resources such as houses, solar panels, livestock and agricultural crops where the estimated mean loss and damage per household was worth USD 3,170. This study reported that the rich shrimp farmers encountered proportionately more economic loss and damage than their poor counterparts. However, this does not mean that the poor suffered less. The current study found a range of non-economic loss and damage in different aspects of the shrimp farmers' household members such as unbearable mental pain, deterioration of health, physical injuries, disabilities, etc. and access to services (e.g., inadequate food, lack of safe drinking water, lack of medical facilities, disruption of education systems), social infrastructure (e.g., damage of roads and markets) and disturbance of cultural functions. The findings suggest that urgent short- and long-term actions may be taken to save the aquaculture farms and dependent livelihoods from economic and non-economic loss and damage to cyclones in future.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.420-426
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• 2022

Breast cancer is among the cancers that may be healed as the disease diagnosed at early times before it is distributed through all the areas of the body. The Automatic Analysis of Diagnostic Tests (AAT) is an automated assistance for physicians that can deliver reliable findings to analyze the critically endangered diseases. Deep learning, a family of machine learning methods, has grown at an astonishing pace in recent years. It is used to search and render diagnoses in fields from banking to medicine to machine learning. We attempt to create a deep learning algorithm that can reliably diagnose the breast cancer in the mammogram. We want the algorithm to identify it as cancer, or this image is not cancer, allowing use of a full testing dataset of either strong clinical annotations in training data or the cancer status only, in which a few images of either cancers or noncancer were annotated. Even with this technique, the photographs would be annotated with the condition; an optional portion of the annotated image will then act as the mark. The final stage of the suggested system doesn't need any based labels to be accessible during model training. Furthermore, the results of the review process suggest that deep learning approaches have surpassed the extent of the level of state-of-of-the-the-the-art in tumor identification, feature extraction, and classification. in these three ways, the paper explains why learning algorithms were applied: train the network from scratch, transplanting certain deep learning concepts and constraints into a network, and (another way) reducing the amount of parameters in the trained nets, are two functions that help expand the scope of the networks. Researchers in economically developing countries have applied deep learning imaging devices to cancer detection; on the other hand, cancer chances have gone through the roof in Africa. Convolutional Neural Network (CNN) is a sort of deep learning that can aid you with a variety of other activities, such as speech recognition, image recognition, and classification. To accomplish this goal in this article, we will use CNN to categorize and identify breast cancer photographs from the available databases from the US Centers for Disease Control and Prevention.

• 한국지반환경공학회 논문집
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• 제23권3호
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• pp.5-13
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• 2022

본 논문은 기존에 설치되어있는 국내 일반도로용, 고속도로용 낙석방지울타리의 방호성능을 알아보기 위해 100kJ급의 낙석에너지를 이용한 취약부위를 파악하기 위한 시험을 실시하였다. 국내의 경우 국외에 비해 낙석방지울타리의 성능 등급(48~61kJ)이 매우 낮은 편이다. 만약 높은 낙석에너지가 발생했을 시 기능을 제대로 할 수 있는지 파악할 필요가 있으며, 또한 더 나아가 기존에 설치된 낙석방지울타리에 100kJ급으로 향상시킬 수 있는 보강 기술이 개발되어야 한다. 따라서 본 연구는 기존의 낙석방지울타리 시스템(일반도로용, 고속도로용)에 100kJ급 낙석에너지를 이용하여 방호성능을 확인하고, 지주 및 와이어로프, 망의 취약부위를 파악하며, 나아가 기존 설치되어있는 낙석방지울타리(48~61kJ)를 해체하지 않고 100kJ급의 보강 기술을 개발하기 위한 기초 자료로 사용될 예정이다.

• ALGAE
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• 제37권2호
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• pp.105-121
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• 2022

Modern seaweed farming relies heavily on seedlings from natural beds or vegetative cuttings from previous harvests. However, this farming method has some disadvantages, such as physiological variation in the seed stock and decreased genetic variability, which reduces the growth rate, carrageenan yield, and gel strength of the seaweeds. A new method of seedling production that is sustainable, scalable, and produces a large number of high-quality plantlets is needed to support the seaweed farming industry. Recent use of tissue culture and micropropagation techniques in eucheumatoid seaweed production has yielded promising results in increasing seed supply and growing uniform seedlings in large numbers in a shorter time. Several seaweed species have been successfully cultured and regenerated into new plantlets in laboratories using direct regeneration, callus culture, and protoplast culture. The use of biostimulants and plant growth regulators in culture media increases the seedling quality even further. Seedlings produced by micropropagation grew faster and had better biochemical properties than conventionally cultivated seedlings. Before being transferred to a land-based grow-out system or ocean nets for farming, tissue-cultured seedlings were recommended to undergo an acclimatization process to increase their survival rate. Regular monitoring is needed to prevent disease and pest infestations and grazing by herbivorous fish and turtles during the farming process. The current review discusses recent techniques for producing eucheumatoid and other valuable seaweed farming materials, emphasizing the efficiency of micropropagation and the transition from laboratory culture to cultivation in land-based or open-sea grow-out systems to elucidate optimal conditions for sustainable seaweed production.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.961-965
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• 1998

The rapid development of small-scale (1-10 MJ) Superconducting Magnetic Energy Storage Systems (SMES) can be explained by real perspective of practical implementation of these devices in electro power nets. However the serious problem of all high mechanically stressed superconducting coils-problem of training and degradation (decreasing) of operating current still exists. Moreover for SMES systems this problems is more dangerous because of pulsed origin of mechanical stresses-one of the major sources of local heat disturbances in superconducting coils. We investigated acoustic emission (AE) phenomenon on model and 0.5 MJ SMES coils taking into account close correlation of AE and local heat disturbances. Two-coils 0.5 MJ SMES system was developed, manufactured and tested at Russian Research Center in the frames of cooperation with Korean Electrical Engineering Company (KEPCO) [1]. The two-coil SMES operates with the stored energy transmitted between coils in the course of a single cycle with 2 seconds energy transfer time. Maximum operating current 1.55 kA corresponds to 0.5 MF in each coil. The Nb-Ti-based conductor was designed and used for SMES manufacturing. It represents transposed cable made of Nb-Ti strands in copper matrix, several cooper strands and several stainless steel strands. The coils are wound onto fiberglass cylindrical bobbins. To make AE event information more useful a real time instrumentation system was used. Two main measured and computer processed AE parameters were considered: the energy of AE events (E) and the accumulated energy of AE events (E ). Influence of current value in 0.5 MJ coils on E and E was studied. The sensors were installed onto the bobbin and the external surface of magnets. Three levels of initial current were examined: 600A, 1000A, 2450 A. An extraordinary strong dependence of the current level on E and E was observed. The specific features of AE from model coils, operated in sinusoidal vibration current changing mode were investigated. Three current frequency modes were examined: 0.012 Hz, 0.03 Hz and 0.12 Hz. In all modes maximum amplitude 1200 A was realized.

• 수산해양기술연구
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• 제59권2호
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• pp.164-171
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• 2023

This study analyzed the flow inside floating seedling equipment for Scapharca subcrenata. Due to the aging society of fishing villages, it is impossible to continuously input the labor force. Therefore, it is necessary to improve efficiency. Scapharca subcrenata has high per capita consumption. It serves as an important aquatic food resource. Scapharca subcrenata culture tends to be highly dependent on the natural environment. Production of Scapharca subcrenata is difficult to predict with low stability. In the past, manpower directly installed bamboo nets in mudflats. The seedling equipment devised in this study is a floating type and can be freely moved on the sea according to the prediction of Scapharca subcrenata generation. The flow around the floating seedling equipment was analyzed by numerical analysis. The physical phenomena of the flow around the net inside the floating seedling equipment were visualized. As a result, the space between the floating seedling equipment and the bottom net and the space between the net groups showed a lower flow rate than the inlet flow rate. It is expected that the low flow rate of the floating seedling equipment will have a positive effect on the attachment of Scapharca subcrenata.

• 한국방재안전학회논문집
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• 제15권4호
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• pp.79-86
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• 2022

국립공원공단에서는 낙석위험지역에 낙석방지시설(낙석방지망, 낙석방지울타리, 피암터널 등)을 설치하거나 우회탐방로를 개설하는 등 안전 환경 조성을 위한 노력을 하고 있다. 그러나 기후변화에 따른 집중호우나 겨울철 이상 고온, 지반의 노령화로 인한 풍화와 절리현상으로 매년 낙석 발생이 증가하는 추세이며, 기존 낙석위험지역 관리방안에 대한 개선의 필요성이 대두되었다. 본 연구에서는 우리나라 국립공원 중 치악산 국립공원 황골지구를 대상으로 하여 낙석 발생의 위험이 있는 시범지역을 선정한 후 Rockfall 프로그램을 이용한 낙석 분석을 수행하였으며, 분석 결과에 따라 시범지역에 계측시스템과 결합한 대책공법을 적용하여 모니터링을 실시하였다. 이를 통해 낙석의 지속적 관리와 모니터링을 위한 낙석 관리방안을 제시하였다.

• 한국컴퓨터정보학회논문지
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• 제14권1호
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• pp.173-181
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• 2009

본 논문은 온톨로지 작성에 사용되는 RDF(Resource Description Framework) 모델을 컬러 페트리 넷 모델로 변환하는 알고리즘을 제안한다. 제안하는 알고리즘은 RDF 모델의 클래스와 프로퍼티들을 컬러 페트리 넷의 플레이스로 매핑하여 RDF 모델의 의미를 컬러 페트리 넷의 토폴로지로 변환한 다음 클래스와 프로퍼티들 간의 관계를 토큰의 전이로 나타냄으로써 RDF의 문장들을 컬러 페트리 넷에 반영한다. RDF 문장들을 반영하는 기본적인 방법은 주어와 객체를 나타내는 토큰들의 순서쌍으로 구성된 토큰을 생성하여, 술어를 나타내는 자리로 전이하는 방법이다. 주어진 RDF 모델을 제안하는 방법으로 실제 CPNTools를 이용하여 컬러 페트리 넷 모델로 변환하고, RDF 질의에 대한 추론과 답을 CPNTools에서 구하는 사례를 보였다.

• 대한토목학회논문집
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• 제43권4호
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• pp.511-523
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• 2023

철근콘크리트 손상 감지를 위한 무인항공기와 딥러닝 연계에 대한 연구가 활발히 진행 중이다. 컨볼루션 신경망은 객체 분류, 검출, 분할 모델의 백본으로 모델 성능에 높은 영향을 준다. 사전학습 컨볼루션 신경망인 모바일넷은 적은 연산량으로 충분한 정확도가 확보 될 수 있어 무인항공기 기반 실시간 손상 감지 백본으로 효율적이다. 바닐라 컨볼루션 신경망과 모바일넷을 분석 한 결과 모바일넷이 바닐라 컨볼루션 신경망의 15.9~22.9% 수준의 낮은 연산량으로도 6.0~9.0% 높은 검증 정확도를 가지는 것으로 평가되었다. 모바일넷V2, 모바일넷V3Large, 모바일넷 V3Small은 거의 동일한 최대 검증 정확도를 가지는 것으로 나타났으며 모바일넷의 철근콘트리트 손상 이미지 특성 추출 최적 조건은 옵티마이저 RMSprop, 드롭아웃 미적용, 평균풀링인 것으로 분석되었다. 본 연구에서 도출된 모바일넷V2 기반 7가지 손상 감지 최대 검증 정확도 75.49%는 이미지 축적과 지속적 학습으로 향상 될 수 있다.