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16th International Conference on Fracture and Damage Mechanics, 2017

作者： Prabowo, Aditya Rio Sohn, Jung Min Byeon, Jung Hoon Bae, Dong Myung Zakki, Ahmad Fauzan Cao, Bo Interdisciplinary Program of Marine Convergence Design Pukyong National University Busan48513 Korea Republic of Department of Naval Architecture and Marine Systems Engineering Pukyong National University Busan48513 Korea Republic of Department of Naval Architecture Diponegoro University Semarang50268 Indonesia China Shipbuilding Industry Corporation Economic Research Center Beijing100012 China

ISBN: (纸本)9783035711684

Demand to increase safety for water transportation, namely ship is continuously rising as various accidental loads may threat condition of target structure, i.e. ship. Several possibilities of impact scenario can occur with various indenters, for example stranding to a grounded ice. In this work, a study of structural behaviour accounting for interaction between the ship structure and indenter is conducted. Numerical simulation is performed using finite element method to estimate damage extent of the double bottom. In analysis, the indenter for grounding scenario is applied by characteristic of the ice properties to obtain estimated response of the structure in experiencing impact on polar territory. Impact scenario is defined into three different locations, namely girder and space between two girders. Finally, tendency of the damage per destroyed component is summarized. © 2017 Trans Tech Publications, Switzerland.

关键词： Ice

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Design and calculation of mechanical system for solar-powered electric boat

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IOP Conference Series: Earth and Environmental Science 2018年第1期105卷

作者： Sunaryo Dendi Nurachman Pradhana S Imfianto Naval Architecture and Marine Engineering Study Program Department of Mechanical Engineering Universitas Indonesia Depok 16424 Indonesia

Indonesian government has a flagship program that is to promote the nation through the maritime sector and make Indonesia as Global Maritime Fulcrum. To achieve that, sea transportation is very important for the development of Indonesia. But sea transportation is also the highest contributor to the air pollution and global warming. In order to reduce the source of global warming Indonesian Government has a strategic plan to gradually replace the use of fossil energy with renewable energy. One of the renewable energy that can be used effectively in Indonesia is solar energy, because Indonesia located along the equator and has a high intensity of sunlight that means it has excellent solar energy availability. In attempt to contribute to the Government's energy strategic plan, the research is aimed to design a solar-powered electric boat with single pilot. The project is a further development of the solar boat created by the Universitas Indonesia team that participated in the International Solar-boat Challenge competition in the Netherlands. The paper is focused on the design and calculation of its mechanical system. The system is divided into propulsion system, steering system, and bilge pump system. The research is conducted based on literature study, discussion with experts, and surveys to the solar-powered electric boat had been designed previously for the race. Collected data are then used as input for the calculation and simulation of the vessel being designed. It is expected that the study could optimize the mechanical system of the solar-powered electric boat, and can be developed for recreational use in Indonesian waters.

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Low cost underwater acoustic localization 173

Low cost underwater acoustic localization

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173rd Meeting of Acoustical Society of America, Acoustics 2017 and 8th Forum Acusticum

作者： Ruland, Eduardo Alexander Iscar Shree, Atulya Goumas, Nicholas Johnson-Roberson, Matthew Naval Architecture and Marine Engineering University of Michigan Ann ArborMI48109 United States Robotics Program University of Michigan Ann ArborMI48109 United States University of Michigan Ann ArborMI48109 United States

Over the course of the last decade, the cost of marine robotic platforms has significantly decreased. In part this has lowered the barriers to entry of exploring and monitoring larger areas of the earth's oceans. However, these advances have been mostly focused on autonomous surface vehicles (ASVs) or shallow water autonomous underwater vehicles (AUVs). One of the main drivers for high cost in the deep water domain is the challenge of localizing such vehicles using acoustics. A low cost one-way travel time underwater ranging system is proposed to assist in localizing deep water submersibles. The system consists of location aware anchor buoys at the surface and underwater nodes. This paper presents a comparison of methods together with details on the physical implementation to allow its integration into a deep sea micro AUV currently in development. Additional simulation results show error reductions by a factor of three. © 2018 Acoustical Society of America.

关键词： Travel time

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DispSegNet: Leveraging semantics for end-to-end learning of disparity estimation from stereo imagery

arXiv

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arXiv 2018年

作者： Zhang, Junming Skinner, Katherine A. Vasudevan, Ram Johnson-Roberson, Matthew Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Robotics Program University of Michigan Ann ArborMI48109 United States Department of Mechanical Engineering University of Michigan Ann ArborMI48109 United States Department of Naval Architecture and Marine Engineering University of Michigan Ann ArborMI48109 United States

Recent work has shown that convolutional neural networks (CNNs) can be applied successfully in disparity estimation, but these methods still suffer from errors in regions of low-texture, occlusions and reflections. Concurrently, deep learning for semantic segmentation has shown great progress in recent years. In this paper, we design a CNN architecture that combines these two tasks to improve the quality and accuracy of disparity estimation with the help of semantic segmentation. Specifically, we propose a network structure in which these two tasks are highly coupled. One key novelty of this approach is the two-stage refinement process. Initial disparity estimates are refined with an embedding learned from the semantic segmentation branch of the network. The proposed model is trained using an unsupervised approach, in which images from one half of the stereo pair are warped and compared against images from the other camera. Another key advantage of the proposed approach is that a single network is capable of outputting disparity estimates and semantic labels. These outputs are of great use in autonomous vehicle operation;with real-time constraints being key, such performance improvements increase the viability of driving applications. Experiments on KITTI and Cityscapes datasets show that our model can achieve state-of-the-art results and that leveraging embedding learned from semantic segmentation improves the performance of disparity estimation. Copyright © 2018, The Authors. All rights reserved.

关键词： Semantic Segmentation

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Driving in the Matrix: Can virtual worlds replace human-generated annotations for real world tasks?

Driving in the Matrix: Can virtual worlds replace human-gene...

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2017 IEEE International Conference on Robotics and Automation, ICRA 2017

作者： Johnson-Roberson, Matthew Barto, Charles Mehta, Rounak Sridhar, Sharath Nittur Rosaen, Karl Vasudevan, Ram Department of Naval Architecture and Marine Engineering University of Michigan Ann ArborMI48109 United States Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Robotics Program University of Michigan Ann ArborMI48109 United States Mechanical Engineering University of Michigan Ann ArborMI48109 United States

ISBN: (纸本)9781509046331

Deep learning has rapidly transformed the state of the art algorithms used to address a variety of problems in computer vision and robotics. These breakthroughs have relied upon massive amounts of human annotated training data. This time consuming process has begun impeding the progress of these deep learning efforts. This paper describes a method to incorporate photo-realistic computer images from a simulation engine to rapidly generate annotated data that can be used for the training of machine learning algorithms. We demonstrate that a state of the art architecture, which is trained only using these synthetic annotations, performs better than the identical architecture trained on human annotated real-world data, when tested on the KITTI data set for vehicle detection. By training machine learning algorithms on a rich virtual world, real objects in real scenes can be learned and classified using synthetic data. This approach offers the possibility of accelerating deep learning's application to sensor-based classification problems like those that appear in self-driving cars. The source code and data to train and validate the networks described in this paper are made available for researchers. © 2017 IEEE.

关键词： Object detection

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Automatic color correction for 3D reconstruction of underwater scenes

Automatic color correction for 3D reconstruction of underwat...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Katherine A. Skinner Eduardo Iscar Matthew Johnson-Roberson Robotics Program University of Michigan Ann Arbor MI USA Department of Naval Architecture and Marine Engineering University of Michigan Ann Arbor MI USA

Mapping of underwater environments is a critical task for a range of activities from monitoring coral reef habitats to surveying submerged archaeological sites. While recent advances in methods for terrestrial mapping can achieve dense 3D reconstructions of scenes in real-time, there remains the challenge of transferring these methods to the underwater domain due to characteristic effects on propagation of light through the water column that violate the brightness constancy constraint used in terrestrial techniques. Current state-of-the-art methods for underwater 3D reconstruction exploit a physical model of light propagation underwater to account for such range-dependent effects as scattering and attenuation; however, these methods necessitate careful calibration of attenuation coefficients required by the physical model, or rely on rough estimates of these coefficients from prior lab experiments. The main contribution of this paper is to develop a novel method to achieve simultaneous estimation of attenuation coefficients for color correction during structure recovery of an underwater scene by integrating this estimation directly into the bundle adjustment step, which performs non-linear optimization. To validate the proposed method, an artificial scene is submerged in a pure water tank and surveyed with a stereo camera platform to simulate an underwater robotic survey in a controlled environment. The target structure is imaged in air with an RGB-D sensor to provide ground truth structure and color, and a color calibration board is place in the scene for further reference. Results show that the proposed method can automatically estimate a water-column aware model for color correction of underwater images simultaneously to 3D reconstruction of the submerged scene.

关键词： Attenuation Three-dimensional displays Cameras Image color analysis Image reconstruction Scattering Solid modeling

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Multi-view 3D Reconstruction in Underwater Environments: Evaluation and Benchmark

Multi-view 3D Reconstruction in Underwater Environments: Eva...

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Oceans (Conference)

作者： Eduardo Iscar Katherine A. Skinner Matthew Johnson-Roberson Department of Naval Architecture and Marine Engineering University of Michigan Ann Arbor MI USA Robotics Program University of Michigan Ann Arbor MI USA

ISBN: (纸本)9781509064298;9780692946909

Mapping of underwater environments is a critical task for a range of activities from monitoring coral reef habitats to surveying submerged archaeological sites. In recent years, optical reconstruction methods developed for terrestrial (in air) applications have increasingly been applied to the underwater environment by the marine science community. However, assumptions such as the brightness constancy constraint (BCC) and traditional camera pinhole models, which hold in air, do not apply in the underwater environment. There is a lack of literature about how the violation of these assumptions affects the accuracy of the reconstruction. The main contributions of this paper is to develop a quantitative evaluation of computer vision-based 3D reconstruction methods applied to the underwater domain. Comparisons are presented between low- and high-cost camera systems to quantify the tradeoff between equipment cost and performance.

关键词： habitats surveying submerged performance

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Resistance Analysis of a Semi-SWATH Design Concept in Shallow Water

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Journal of marine Science and Application 2017年第2期16卷 182-189页

作者： Arifah Ali Adi Maimun Yasser M. Ahmed Rahimuddin Marine Technology Center Department of Aeronautics Automotive & Ocean Engineering Universiti Teknologi MalaysiaSkudai 81310 UTM Malaysia Department of Naval Architecture and Marine Engineering Faculty of Engineering Alexandria University Alexandria 21526 Egypt Program Studi Teknik Sistem Perkapalan Universitas Hasanuddin Makassar 90245 Indonesia

Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) form, is studied. The hull is installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0o, 5o, 10o, and 15o. For each configuration, investigations are conducted with depth Froude numbers (FrH) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTM. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.

关键词： resistance wave height semi-SWATH shallow water fin stabilizers

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Analysis of structural behavior during collision event accounting for bow and side structure interaction

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Theoretical & Applied Mechanics Letters 2017年第1期7卷 6-12页

作者： Aditya Rio Prabowo Dong Myung Bae Jung Min Sohn Ahmad Fauzan Zakki Bo Cao Qing Wang Interdisciplinary Program of Marine Convergence Design Pukyong National University Busan 48513 Republic of Korea Department of Naval Architecture Diponegoro University Tembalang Semarang 50268 Central Java Indonesia Department of Naval Architecture and Marine Systems Engineering Pukyong National University Busan 48513 Republic of Korea China Shipbuilding Industry Corporation Economic Research Center Beijing 100012 China College of Shipbuilding Engineering Harbin Engineering University Harbin 150000 China

The main goal of this study was to investigate the effects of selected ship collision parameter values on the characteristics of the absorbed energy in several ship collision scenarios. Non-linear simulations were performed using a finite element method （FEM） to obtain virtual experiment data. In the present research, the size of the side damage from a collision phenomenon were measured and used to verify the numerical configuration together with the calculation results using an empirical equation. Parameters in the external dynamics of a ship collision such as the location of the contact point and velocity of the striking ship were taken into consideration. The internal energy and deformation size on the side structure were discussed further in a comparative study. The effects of the selected parameters on several structural behaviors, namely energy, force, and damage extent were also observed and evaluated in this section. Stiffener on side hull was found to contribute significantly into resistance capability of the target ship against penetration of the striking bow. Remarkable force during penetration was observed to occur when inner shell was crushed as certain velocity was applied in the striking bow.

关键词： Collision phenomenon Bow-side hull interaction Finite element analysisInternal energy Damage extent

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Investigation on the Structural Damage of a Double-Hull Ship, Part I – Ship Collision

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Procedia Structural Integrity 2017年 5卷 935-942页

作者： Aditya Rio Prabowo Seung Jun Baek Jung Hoon Byeon Dong Myung Bae Joung Hyung Cho Jung Min Sohn Interdisciplinary Program of Marine Convergence Design Nam-gu Yongso-ro 45 Daeyeon-dong Busan 48513 South Korea Department of Naval Architecture and Marine Systems Engineering Nam-gu Yongso-ro 45 Daeyeon-dong Busan 48513 South Korea

marine structure is designed to be able to resist various load conditions during its operational period. However, in design process, analysis of accidental loads, such collision and grounding, has not been included for both merchant ship and navy vessel. These loads are spontaneous and several remarkable casualties may occur after collision and grounding taking place. The aim of this paper is to investigate structural damage on the target ship during collision and grounding considering on failure process and damage extent. This work is divided into two parts which in the Part I, ship collision is discussed, and the Part II deals with interaction of ship structure with sea bottom in grounding. In the Part I - Ship Collision, condition of the side structure is observed, including the inner hull after impact which is considered as the key to determine safety condition of ship cargo. A passenger ship is modelled in this work and designated as the struck ship which will be struck by the striking ship in collision process. Resistance capability of the double-hull structure against side collision is evaluated. Virtual experiment is conducted by nonlinear finite element method in order to calculate several dynamic collision scenarios which are built based on physical parameter, namely target location. Based on calculation results, damage on the side hull is found to be highly influenced by relative height between two ships prior collision. Crashworthiness criteria are summarized and result tendency indicates that in the mentioned location, the striking ship produces larger tearing on the lower part of the struck ship. Contribution of each collision scenario on the resultant force is presented in later part in order to observe structural behaviour of each determined location in encountering side collision.

关键词： Impact phenomenon ship collision non-linear FEM damage extent internal energy

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