• Journal of Advanced Research in Ocean Engineering
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• 제2권3호
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• pp.150-157
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• 2016

When blocks are supported on a dock, huge reaction forces concentrated at the supports cause structural damage owing to local stress concentrations. Thus, the supports should be arranged to avoid local failure from the reaction forces by redistributing those forces. Docking analyses to determine the proper blocks and their support arrangements are introduced so that the local stresses are minimized to warrant the safety of the docking supports. Local stresses enforced by the support arrangement should be evaluated by finite element analysis (FEA). However, it is difficult to consider an accurate 3D geometry of the blocks in the finite element model because the structural design information is too complicated to determine within several days using the FEA model. This paper presents a simplified FE model to evaluate the safety of the arrangement of supports using a simplified grillage element. The grillage element can be efficiently used to obrain the reaction forces in docking analysis becasuse the reaction forces at the supports are enough to assess the safety of block. Since a simplified grillage model of the entire ship cannot accurately calculate the local stresses, an optimized modeling method based on the grillage element was introduced. The local reaction forces obtained by the proposed approach and three-dimensional FEA were discussed for typical types of ships. It is shown that the reaction forces obtained by the present grillage model are in reasonably good agreement with the FEA model.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권4호
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• pp.217-222
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• 2017

본 연구에서는 사람을 대신하여 험난한 지형에서 위험작업을 수행이 가능한 지상로봇과 짧은 시간 안에 원거리 비행이 가능한 드론과의 결합을 통해 위험 상황에서의 효과적인 협업이 가능한 시스템을 구현하였다. 최근 관련 연구는 드론을 수용할 수 있는 무인지상차량이나 4족 로봇에 관한 연구가 있었으나 전체 가용 시간의 장점에 비해 대규모 로봇을 필요로 하여 현장에서 적용하기엔 어려움이 있었다. 본 논문에서는 경량 드론에 장착된 임베디드 웹캠과 영상처리 알고리즘을 사용하여 객체의 한 유형인 마커를 Canny Edge 알고리즘 및 특정한 Template matching 방법을 통하여 비행 중 실시간 검출한 결과를 보여주며, 지상로봇위에 표시된 마커의 2차원적 위치 정보 획득과 레이저 센서를 이용한 상대거리 확보를 융합하여 지상로봇과 드론간의 도킹을 구현하는 시스템을 제안하였다. 실험을 통하여 제안된 시스템은 50회의 도킹 시도에서 95%의 도킹 성공률을 보였으며 6가지의 Template mateching 방법 중 시스템에 적용할 수 있는 2가지의 템플릿 매치 방법을 제시하였다.

• 통합자연과학논문집
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• 제4권4호
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• pp.273-277
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• 2011

It's a threat for the public health that H1N1 (Influenza virus A) causes disease and transmits among humans. WHO (world health organization) declared that the infections caused by the new strain had reached pandemic proportions. The approved neuraminidase inhibitors (Zanamivir and Oseltamivir) and related investigative drug (BCX-1812) are potent, specific inhibitors of influenza A and B viruses. These drugs are highly effective to prevent influenza A and B infections. Early therapeutic use reduces illness duration and respiratory complications. Recently, we found one of the potent inhibitor of erystagallin A ($IC_{50}$ of 2.04 ${\mu}M$) for neuraminidase target, this inhibitor shows most similar structure to its natural substrate, sialic acid. Therefore, we chose 1l7f to get the receptor structure for docking study among many crystal structures. A docking study has been performed in Surflex-Dock module in SYBYL 8.1. In the present study, we attempt to compare the docking studies of pterocarpin and erystagallin A with neuraminidase receptor structure. In the previous report, the methoxy group of pterocarpin had H-bonding with Arg residues. The present docking results for erystagallin A showed the backbone of hydroxyl group shows significant H-bonding interactions with Arg152 and Arg292. The results showed that erystagallin A interacts more favorably with distinctive binding site rather than original active site. Therefore, we tried to reveal plausible binding mode and important amino acid for this inhibitor using docking and site id search calculations of Sybyl. The results obtained from this work may be utilized to design novel inhibitors for neuraminidase.

• 한국통신학회논문지
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• 제35권9B호
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• pp.1314-1321
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• 2010

선박 접안 유도시스템은 선박 내에 장착된 위치 기반 UWB(Ultra WideBand)와 해안에 설치된 리더기를 통해 받은 접안 지점 내의 선박 정박 유무 정보를 바탕으로 관제시스템이 접안을 요청한 선박에 대해 선박의 크기와 종류를 판별하여 그 결과에 따라 접안이 가능한 지점의 위치 정보를 해당 선박에 무선 송출하여 선박의 접안을 유도한다. 이는 선박의 정박시간 대기로 발생하는 불필요한 연료의 낭비와 접안 과정 중 발생하는 충돌 사고를 예방하여 안전성을 제시할 수 있다. 본 연구에서는 위치기반 UWB를 이용한 선박 접안 유도시스템의 테스트베드를 구현하였다. 또한 java 기반의 사용자 인터페이스를 구현하여 모바일 기기 등을 통해 실시간으로 동종의 선박들 가운데에서 사용자의 선박의 위치를 쉽게 인지할 수 있도록 정박 위치 정보를 제공하는 편의성을 제공한다.

• 약학회지
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• 제53권4호
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• pp.222-227
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• 2009

Human topoisomerase I (Topo I) plays a pivotal role in cell replication, transcription and repair and, therefore, is an important anti-cancer target. 20S-camptothecin (CPT) is a representative Topo I inhibitor. Compounds belonging to CPT family inhibit the religation step of Topo I-DNA by binding to the DNA cleavage site. Computational docking studies with Surflex-Dock were carried out to investigate the binding modes between Topo I-DNA binary complex structure and the ligand such as 20S-CPT and 9,10-substituted 20S-CPT analogues. The docking results demonstrated that most of the compounds with $IC_{50}$ value under $0.5{\mu}M$ intercalated exactly between the -1 and +1 DNA bases, deeply toward the cleavage site. The complex was stabilized by hydrogen-bonding and hydrophobic interactions with both the enzyme and the DNA. The compounds with $IC_{50}$ value above $0.5{\mu}M$ were poorly docked and did not intercalate. In addition, the docking results confirmed the overall correlation between the $IC_{50}$ values and docking scores, indicating the possible use of the modeling for the prediction of biological activity and design of potential inhibitors.

• 대한조선학회논문집
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• 제45권6호
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• pp.710-718
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• 2008

This paper presents a simple and fast approach to plan the arrangement of supports and to do a ship docking analysis. The unpredicted structural damages often happen from a docking works as the size of ships are getting larger and larger. In docking a ship, excessive reaction forces from supports are primary causes of the structural damage. The grillage analysis method is employed to simply calculate only the reaction forces at supports. The grillage modeling strategies are proposed to improve the accuracy. In this paper, the results obtained by the proposed approach are compared with those of the current whole-ship FEA for typical types of ships. Comparison shows that the results from the present grillage approaches are reasonably in a good agreement with the 3-D full F.E one. Finally, an integrated program developed for the ship docking analysis is described.

• 우주기술과 응용
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• 제1권1호
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• pp.7-22
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• 2021

본 논문에서는 국내 최초로 개발 중인 랑데부/도킹 기술검증용 초소형위성의 지상 환경에서의 도킹 단계 시험 결과에 대해 기술하였다. 랑데부/도킹 기술은 우주기술 중 고난이도 기술로서 우주 궤도상에서 상대 물체에 접근한 후 작업을 수행하는 데 매우 핵심적인 기술이기도 하다. 본 논문에서는 에어베어링 장치를 이용하여 체이서가 모의 타겟으로 접근하여 최종적으로 도킹하는 단계의 지상시험 결과에 대해 기술하고자 한다. 본 논문에서 검증된 2차원 평판에서 도킹 단계에서의 추력 제어 알고리즘과 시각 기반 센서를 이용한 상대물체 인식 및 상대거리 추정 알고리즘을 기반으로 추후에는 우주에서의 시험을 위한 3차원 공간에서의 랑데부/도킹 알고리즘으로 확장·개발하는 데 이용하고자 한다.

• Natural Product Sciences
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• 제28권2호
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• pp.45-52
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• 2022

The identification of Plasmodium falciparum enoyl acyl-carrier protein reductase (pfENR) is considered as a potential biological target against malaria. Trema orientalis is considered a rich source of phytochemicals useful in malaria treatment. This study evaluated the in-vitro inhibitory activity of the extract and isolated compounds of T. orientalis leaf; the isolated compounds and the analogues of the most active compound were subjected to in-silico molecular docking studies on pfENR. The methanolic extract of T. orientalis was subjected to repeated chromatographic separation which led to the isolation of some compounds. The isolated compounds from the plant were examined for their antimalarial activity using β-hematin inhibition assay. Virtual screening via molecular docking and ADMET studies were conducted to gain insight into the mechanism of binding of ligand and to identify effective pfENR inhibitors. The isolated compounds and the analogues of the most active isolates were gotten from PubChem library for use in docking study. Hexacosanol and β-sitosterol showed inhibition of the β-hematin formation. The docking results showed that hexacosanol, β-sitosterol and the analogues of β-sitosterol displayed binding energy ranging between -6.1 kcal/mol and -11.6 kcal/mol. Sitosterol glucoside has the highest docking score. Some of the ligands showed more binding affinity than known bioactive compounds used as reference. Analogues of β-sitosterol has been shown to be potential inhibitors of pfENR, therefore, the findings from this study suggest that sitosterol glucoside and ergosterol peroxide could act as antimalarial agents after further lead optimisation investigations.

• 한국콘텐츠학회논문지
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• 제8권12호
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• pp.441-448
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• 2008

분자 도킹 실험은 일반적으로 계산 량이 매우 많아 슈퍼 컴퓨팅 파워를 요구하는 실험이다. 따라서 시간이 많이 소요되기 때문에 일반적으로 CPU가 탑재된 컴퓨터를 여러 대 묶어서 사용하는 분산 환경 혹은 그리드 환경에서 실험을 수행하고 있다. 이와 같은 실험 환경은 시간적, 공간적 제약성이 많아 일반적으로 과학자들이 접근하기가 어렵다. 그래서 근래에는 많은 CPU를 사용하기 보다는 월등히 성능이 높은 GPU를 병렬 화하여 과학 분야에 계산하는 연구가 매우 활발히 이루어지고 있는 추세이다. CUDA는 병렬 GPU 프로그래밍을 가능하게 하는 공개 기술이다. 본 논문에서는 이러한 CUDA 기술을 사용하여 분자 도킹 실험을 할 수 있는 시스템을 제안한다. 또한, 분자 도킹 실험에 있어서 중요한 에너지 최소화 계산을 병렬 화하는 알고리즘을 제안한다. 이와 같은 실험을 검증하기 위해 본 논문에서는 일반적인 CPU에서 분자 도킹 실험 시간과 본 논문에서 제안한 병렬 CPU 기반의 분자 도킹 시간을 비교 분석 하였다.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1479-1484
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• 2008

Protein tyrosine phosphatase (PTP) 1B is the superfamily of PTPs and a negative regulator of multiple receptor tyrosine kinases (RTKs). Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been proposed as a strategy for the treatment of type 2 diabetes and obesity. Recently, it has been reported that amentoflavone, a biflavonoid extracted from Selaginella tamariscina, inhibited PTP1B. In the present study, docking model between amentoflavone and PTP1B was determined using automated docking study. Based on this docking model and the interactions between the known inhibitors and PTP1B, we determined multiple pharmacophore maps which consisted of five features, two hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. Using receptor-oriented pharmacophore-based in silico screening, we searched the biflavonoid database including 40 naturally occurring biflavonoids. From these results, it can be proposed that two biflavonoids, sumaflavone and tetrahydroamentoflavone can be potent allosteric inhibitors, and the linkage at 5',8''-position of two flavones and a hydroxyl group at 4'-position are the critical factors for their allosteric inhibition. This study will be helpful to understand the mechanism of allosteric inhibition of PTP1B by biflavonoids and give insights to develop potent inhibitors of PTP1B.