• 한국항행학회논문지
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• 제23권5호
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• pp.352-360
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• 2019

본 논문은 센서에 불확실성이 존재하는 무인잠수정에 대한 도킹 평가 알고리즘을 제안한다. 제안된 알고리즘은 상태평가와 확률평가 두 가지의 평가로 구성된다. 상태평가는 무인잠수정이 도킹스테이션에 접근하는 과정 중 심도제어를 통해 도킹스테이션과 동일한 수심에 도달하는데 발생 예상되는 전진거리와 실제 수평거리를 비교함으로써 심도 도달 가능 여부를, 무인잠수정의 최소선회반경으로 인한 접근 불가 영역과 도킹스테이션의 위치를 비교함으로써 충돌 회피를 위한 선회 동작 수행 여부를 확인한다. 상태평가를 만족하며 무인잠수정이 도킹스테이션에 일정 거리 이상 접근한 경우 확률평가를 수행하여 무인잠수정의 방향각과 도킹스테이션에 대한 상대위치, 그리고 센서 불확실성을 기반으로 도킹 성공확률을 산출한다. 최종적으로 산출된 도킹 성공확률을 설계된 문턱 값과 비교함으로써 도킹 수행 여부를 결정한다. Matlab 기반의 시뮬레이션을 통해 무인잠수정이 도킹스테이션에 접근하는 시나리오를 구성하여 제안하는 알고리즘의 유효성을 검증한다.

• 한국항행학회논문지
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• 제25권3호
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• pp.177-184
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• 2021

본 논문은 무인잠수정을 도킹스테이션에 성공적으로 안전하게 도킹시키기 위해 확률 기반 평가지표를 설계하여 수중 도킹 과정을 평가하는 방법을 제안한다. 제안하는 방법은 무인잠수정 상태와 수중 도킹을 위한 상태 기준의 일치 정도에 따른 도킹 성공 가능성을 확률로써 평가하는 방법이다. 평가는 무인잠수정의 기구학적 구속조건과 도킹 계획을 고려해 정의된 영역 내부에서 수행한다. 평가 과정은 확률밀도함수의 정의, 위치와 방향각 기준과의 차이에 따른 도킹스테이션 도달확률 계산, 확률지표의 산출 순서이며, 이를 통해 실시간으로 수중 도킹 과정을 평가한다. 수조실험을 통해 획득한 무인잠수정 데이터를 분석하여 제안하는 평가지표의 유효성을 검토하였다.

• 대한조선학회 특별논문집
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• 대한조선학회 2006년도 특별논문집
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• pp.89-96
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• 2006

The objective of this paper is to find out a reasonable method for docking analysis of ships. The characteristics of reaction force distribution under docking condition are investigated by carrying out parametric study. To assess the allowable reaction force on keel block from structural strength point of view, two kinds of structural assessment methods are proposed in accordance with expected collapse pattern. In order to verify the proposed method, linear buckling and elasto-plastic large deflection analyses of typical double bottom structure are carried out and the results are compared.

• 해양환경안전학회지
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• 제19권3호
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• pp.290-301
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• 2013

The docking analysis of a global ship structure is requested to evaluate its structural safety against the reaction forces at supports during docking works inside a dry dock. That problem becomes more important recently as the size of ships is getting larger and larger. The docking supports are appropriately arranged in a dock to avoid their excessive reaction forces which primarily cause the structural damages in docking a ship and, up to now, the structural safety has been assessed against the support arrangement by the finite element analysis (FEA) of a global ship structure. However, it is complicated to establish the finite element model of the ship in the current structural design environment of a shipyard and it takes over a month to finish the work. This paper investigates a simple and fast approach to carry out a ship docking analysis by a simplified grillage model and to assign the docking supports position on the model. The grillage analysis was considered from the motivation that only the reaction forces at supports are sufficient to assess their arrangement. Since the simplified grillage model of the ship cannot guarantee its accuracy quantitatively, modeling strategies are proposed to improve the accuracy. In this paper, comparisons between the proposed approach and three-dimensional FEA for typical types of ships show that the results from the present grillage model have reasonably good agreement with the FEA model. Finally, an integrated program developed for docking supports planning and its evaluation by the proposed approach is briefly described.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.9-17
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• 2006

Performing inspections for Hull Condition Monitoring and Assessment as stipulated in IACS unified requirements and IMO's Condition Assessment Scheme (CAS) IMO Resolution MEPC.94(46), 2001, Condition Assessment Scheme, IMO Resolution MEPC.111(50), 2003, Amendments to regulation 13G, addition of new regulation 13H involves a huge amount of measurement data to be collected, processed, analysed and maintained. Information to be recorded consists of thickness measurements and visual assessment of coating and cracks. The amount of data and increasing requirements with respect to condition assessment demand efficient computer support. Currently, due to the lack of standardization for this kind of data, the thickness measurements are recorded manually on ship drawings or tables. In this form, handling of the measurements is tedious and error-prone and assessment is difficult. Data reporting and analysis takes a long time, leading to some repairs being performed only at the next docking of the ship or making an additional docking necessary. The recently started ED funded project CAS addresses this topic and develops-as a first step-a data model for Hull Condition Monitoring and Assessment (HCMA) based on XML-technology. The model includes simple geometry representation to facilitate a graphically supported data collection as well as an easy visualisation of the measurement results. In order to ensure compatibility with the current way of working, the content of the data model is strictly confined to the requirements of the measurement process. Appropriate data interfaces to classification software will enable rapid assessment by the classification societies, thus improving the process in terms of time and cost savings. In particular, decision-making can be done while the ship is still in the dock for maintenance.

• 대한약침학회지
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• 제27권2호
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• pp.91-100
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• 2024

Objectives: Candida albicans is an opportunistic pathogen that occurs as harmless commensals in the intestine, urogenital tract, and skin. It has been influenced by a variety of host conditions and has now evolved as a resistant strain. The aim of this study was thus detect the fluconazole resistant C. albicans from the root caries specimens and to computationally evaluate the interactions of an opaque-phase ABC transporter protein with the Psidium guajava bio-active compounds. Methods: 20 carious scrapings were collected from patients with root caries and processed for the isolation of C. albicans and was screened for fluconazole resistance. Genomic DNA was extracted and molecular characterization of Cdrp1 and Cdrp2 was done by PCR amplification. P. guajava methanolic extract was checked for the antifungal efficacy against the resistant strain of C. albicans. Further in-silico docking involves retrieval of ABC transporter protein and ligand optimization, molinspiration assessment on drug likeness, docking simulations and visualizations. Results: 65% of the samples showed the presence of C.albicans and 2 strains were fluconazole resistant. Crude methanolic extract of P. guajava was found to be promising against the fluconazole resistant strains of C. albicans. In-silico docking analysis showed that Myricetin was a promising candidate with a high docking score and other drug ligand interaction scores. Conclusion: The current study emphasizes that bioactive compounds from Psidium guajava to be a promising candidate for treating candidiasis in fluconazole resistant strains of C. albicans However, further in-vivo studies have to be implemented for the experimental validation of the same in improving the oral health and hygiene.