Information models and functions for CIM in shipbuilding

In order to make significant progress in design and manufacturing systems, all industries must consider integration. This paper considers information models and functions for a computer integrated design and manufacturing system in shipbuilding. The authors propose the product model and several alterative functions for designing a ship's structure, and develop a “ship definition system for computer integrated design and manufacturing.” This system is called SODAS (System of Design and Assembly for Shipbuilding). An object-oriented concept is used to develop this system. In order to define a ship's structure, the authors propose the product models of “parts member” and “parts connection,” and the product models of “Room,” “Unit,” and “Module” are introduced to define the compartments, internal structures and intermediate products of a ship. Therefore, all information about a product from the design to the production stage is stored in the product model. As well as the product model, the “design function,” “cutting function,” and “virtual assembling function” are introduced. By using the design function, any type of ship's structure can be designed, and by using the cutting function, the design of a ship's structure can be cut into smaller elements. By using the virtual assembling function, a simulation of the manufacture of a ship's structure can be carried out.     

Association rule learning to improve deficiency inspection in port state control

ABSTRACT

The inspection of foreign ships in national ports is a critical measure in port state control (PSC), preventing substandard ships from entering national ports. Multifarious inspection items, limited inspection time and inspector manpower are challenging PSC inspection. This research applies data mining to analyze historical PSC inspection records in Taiwan’s major ports to extract potential valuable information for PSC onboard inspections. Using the Apriori Algorithm, the analysis identifies many useful association rules among PSC deficiencies in terms of specific ship characteristics, such as ship types, societies, and flags. The general rules identified show that the items ‘Water/Weathertight conditions’ and ‘Fire safety’ are significantly related. Besides, in the analysis of the various ship types, several different rules are found. After comparing the analysis of ship types and ship societies, it can be observed that the association rules for specific ship types, such as oil tankers, have a better effect than those for individual ship societies do. These identified rules can not only help inspectors effectively spot the associated deficiencies, but also improve the efficiency of PSC inspection. The ports other than Taiwan’s ports can apply a similar analysis method to identify corresponding association rules suitable for their own inspections.     

船体结构腐蚀模型对检测及维修规划的影响

提出了基于风险的船体结构腐蚀优化检测及维修的基本理论框架.最优的检测及维修,是在保证结构在设计工作寿命内的可靠指标大于最低可靠指标的基础上,使结构生命周期内总的期望费用最小.建立了检测、维修及失效事件的安全余量方程,推导了失效及维修概率的计算公式.在此基础上,以船体结构两种常用的腐蚀模型Paik模型和Guedes Soares模型为例,分析了两种模型对最优检测及维修策略的影响.其结果表明,腐蚀模型对最优的检测及维修次数和时间有明显的影响,但是对总的期望费用及失效概率影响不大,而且两种腐蚀模型得出的最优失效概率都是10-3.     

基于风险的船体结构无损检测功能的分级

基于船舶结构传统的经验基础上的检测方法不但带来较高的费用,而且还会产生不必要的检测.针对上述问题,本文提出了基于风险的船舶结构无损检测功能分级方法,采用检测概率、错误识别概率和裂纹出现概率度量检测功能,并修正了错误识别概率的取值范围.根据风险值对无损检测功能进行了分级,研究了风险值随检测概率、错误识别概率和裂纹出现概率的变化规律,并分析了风险值对检测费用、维修费用及失效费用的敏感性.在此基础上,将基于风险的船舶结构无损检测功能分级方法应用于优化检测策略,并用算例证明了文中所提方法的有效性.     

Goal-based standards

The development of goal-based new ship construction standards is a new subject matter of high importance for IMO which has been included in the Organization’s strategic and long-term work plans and also in the work programme of its Maritime Safety Committee. This paper briefly describes the meaning of “goal-based” regulation in general and looks at its application to ship construction. The on-going work at IMO is presented, results achieved to date are explained and an outlook is given regarding the work still to be carried out.     

船舶“防火、探火、灭火”安全检查

文中笔者就日常船舶安全检查中如何发现的船舶＂防火、探火、灭火＂方面的缺陷和缺陷处理措施进行探讨,这些缺陷有些是船舶在设计、建造时未严格执行规范留下的。     

Application of H∞ control in rudder/flap vector robust control of a ship＇s course

Given the uncertainty of parameters and the random nature of disturbances that effect a ships course, a robust course controller should be designed on the basis of rudder/flap vector control. This paper analyzes system uncertainty, and the choice of weighting functions is also discussed. When sea waves operate on a ship, the energy-concentrating frequency varies with the angle of encounter. For different angles of encounter, different weighting functions are designed. For the pole of a nominal model existing in an imaginary axis, the bilinear-transform method is used. The ＂2-Riccati＂ equation is adopted to solve the H∞ controller. A system simulation is given, and the results show that, compared with a PID controller, this system has higher course precision and more robust performance. This research has significant engineering value.     

Fuzzy logic based decision making system for collision avoidance of ocean navigation under critical collision conditions

This paper focuses on a fuzzy logic based intelligent decision making system that aims to improve the safety of marine vessels by avoiding collision situations. It can be implemented in a decision support system of an oceangoing vessel or included in the process of autonomous ocean navigation. Although Autonomous Guidance and Navigation (AGN) is meant to be an important part of future ocean navigation due to the associated cost reduction and improved maritime safety, intelligent decision making capabilities should be an integrated part of the future AGN system in order to improve autonomous ocean navigational facilities. In this study, the collision avoidance of the Target vessel with respect to the vessel domain of the Own vessel has been analyzed and input, and output fuzzy membership functions have been derived. The if–then rule based decision making process and the integrated novel fuzzy inference system are formulated and implemented on the MATLAB software platform. Simulation results are presented regarding several critical collision conditions where the Target vessel fails to take appropriate actions, as the “Give way” vessel to avoid collision situations. In these situations, the Own vessel is able to take critical actions to avoid collisions, even when being the “Stand on” vessel. Furthermore, all decision rules are formulated in accordance with the International Maritime Organization Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), 1972, to avoid conflicts that might occur during ocean navigation.     

内河水网地区船舶安全检查工作的研究

文中结合船舶动态管理系统(2.0)的实施以及长期的从事船舶安全检查管理工作经验,总结分析当前内河水网地区船舶安全检查工作现状,分析其深在的原因,并提出船舶安检建设性意见。     

AIS与罗经的相互关系和技术要求

此文探讨AIS与罗经的相互关系和技术要求,以及如何在船舶检验工作中加以应用,使船舶更好满足SOLAS公约及船检法规、规范的要求,供验船师、PSCO和相关技术人员参考。     

船旗国监督检查中对船舶维护保养之体系缺陷的检查和处理

该文通过对船旗国监督检查中船舶维护保养方面缺陷的进一步分析,试图找出缺陷背后船舶和岸基管理在船舶安全营运和防止污染管理体系运行方面存在的具体问题,一方面指导海事执法人员在船旗国监督检查中有效履行职责,另一方面也指导船舶管理公司和船长落实安全生产主体责任,有效运行船舶安全管理体系,切实提升船舶安全营运水平。     

PSC检查中救生设备常见缺陷与防范

船舶救生设备的管理一直是船舶安全工作的重要内容之一。然而,在实施PSC检查中发现,船舶救生设备仍存在许许多多的缺陷和安全隐患,以至于船舶被港口国监督滞留。文中指出了安检中发现的船舶救生设备常见的缺陷,并提出了做好船舶救生设备日常维护和管理的对策与建议。     

Underwater acoustic imaging: image due to a specular reflector in the geometrical-acoustics limit

In underwater acoustic imaging, which is used to produce high-quality images in turbid waters, a specular reflector can produce a “pseudoimage” of the receiving array at the reflecting surface. Based on the “geometrical approximation” (which is similar to geometrical acoustics), formulae are derived for the size and shape of the pseudoimage for both flat and curved reflectors. For curved reflectors, described by two principal radii of curvature, the formulae also assume the “large-range approximation.” The formulae allow radii of curvature to be determined from an image. Also discussed briefly are some possible extensions and the role of nongeometrical effects.     

New method for ship finite element method preprocessing based on a 3D parametric technique

A new method for ship finite element method (FEM) preprocessing is presented as well as its program development. The method is applicable for all kinds of ships at different levels, such as a whole ship, cargo hold parts or detailed structures. The 3D parametric technique is used when creating ship structures, which improves the modeling efficiency greatly and makes the model easy to modify. A 3D geometric constraint solver is developed to solve the constraint system of the parametric model. A meshing procedure is presented to automatically convert the parametric structure model into a finite element model, by which high quality mesh is generated in the stress concentrated area. It also becomes possible to create finite element models for different levels from the same structure model. Using this method, the engineers avoid much of the complex and laborious work of FEM preprocessing, which consumes a very significant amount of time in finite element analysis, and can pay more attention to post-processing. This method has proved to be practical and highly efficient by several engineering trials. This work is sponsored by “Liaoning BaiQianWan Talents Program”.     

Configuration estimation method for preliminary cost of ships based on engineering bills of materials

Ships are complex engineering structures that are designed and built on the basis of technical experience. A shipowner will often be required to estimate the price of a new ship on the basis of the value of comparable ships identified in trade journals. Similarly, shipbuilders are often interested in estimating approximate costs during the tendering phase in order to determine whether a ship is likely to be competitive for a particular order. Thus, when designing a ship prior to having obtained a contract, one of the most important processes is the estimation of approximate costs, including materials, associated labor, and overhead. During this preliminary design phase, the design is temporary and subject to change based on variations in the shipowner’s requirements. Hence, quick and flexible responses are key during this period and an integral aspect of the competitive powers of the shipbuilder. Given this environment, we propose a “configuration estimation method.” Our method is based on the configuration design method that is widely used in three-dimensional (3D) computer aided design (CAD) systems. We assume that a product lifecycle management system is furnished and that the cost is then estimated via the configuration of the ship, using an engineering bill of materials (E-BOM). In referring to the E-BOM, we utilize technical parametric costs derived from similar ships built previously. Using the proposed method, it is possible to obtain an accurate list of materials from the quotation, as well as a detailed work assessment for labor costs and overhead rates, so that reliable cost estimates can be generated quickly and flexibly. To demonstrate the practical applicability and effectiveness of the proposed method, we implement the prototype of a shipbuilding configuration estimation system by using a Microsoft Structured Query Language database and an E-BOM from AVEVA Marine version 12.01, which is a representative CAD system for shipbuilding.     

船舶综合数字信息系统研究与探讨

船舶综合数字信息系统将船舶上的各部分互联为一个实现信息互通的整体,这对于提高船舶综合信息自动化程度有重要作用,具有重要的理论和应用价值.论文系统地论述了船舶综合数字信息系统的概况、国内外研究现状,绘制了船舶综合数字信息系统的结构框图;描述了船舶综合信息系统的各个组成部分及其在系统中的地位和作用,展望了船舶综合信息系统的发展方向.     

A fuzzy failure mode and effects approach to analyse concentrated inspection campaigns on board ships

ABSTRACT

Maritime actions against substandard operations of ships are a great deal of memorandum of understanding (MoUs) under regional basis agreements among port state control (PSC) organisations. Herein, concentrated inspection campaigns (CIC), performed by the different members of MoUs in certain periods, are a monitoring strategy to effectively control the core operational matters encountered in fire-safety systems, propulsion and auxiliary machinery system, lifesaving appliances, working conditions on board ships, etc. This paper proposes a quantified maritime safety analysis based on fuzzy failure mode and effects analysis (FMEA) to evaluate CIC database of MoUs in order to achieve advance creative solutions. Demonstration studies are performed on the special database on fire-safety system deficiencies. Since the fuzzy FMEA outcomes point out the risk prioritisation numbers and relevant control options, the paper attempts to transform CIC feedback into useful information in terms of enhancing the ship PSC inspection concept (e-PSC inspection). The paper theoretically contributes to safety analysis methods in literature while demonstration of e-PSC inspections offers an insight into maritime industry in safety improvement.     

Predictive power of inspection outcomes for future shipping accidents – an empirical appraisal with special attention for human factor aspects

This paper investigates whether deficiencies detected during port state control (PSC) inspections have predictive power for future accident risk, in addition to other vessel-specific risk factors like ship type, age, size, flag, and owner. The empirical analysis links accidents to past inspection outcomes and is based on data from all around the globe of PSC regimes using harmonized deficiency codes. These codes are aggregated into eight groups related to human factor aspects like crew qualifications, working and living conditions, and fatigue and safety management. This information is integrated by principal components into a single overall deficiency index, which is related to future accident risk by means of logit models. The factor by which accident risk increases for vessels with above average compared to below average deficiency scores is about 6 for total loss, 2 for very serious, 1.5 for serious, and 1.3 for less-serious accidents. Relations between deficiency scores and accident risk are presented in graphical format. The results may be of interest to PSC authorities for targeting inspection areas, to maritime administrations for improving asset allocation based on prediction scenarios connected with vessel traffic data, and to maritime insurers for refining their premium strategies.     

Investigations of vehicle securing without lashings for Ro-Ro ships

To reduce the area on deck occupied by each car and the labour and time required for lashing and unlashing cars, it has been proposed by the author that in some conditions, cars on decks could be transported without lashing. To evaluate cargo securing based on this “lashing-free” concept, computational code was developed to calculate the vehicle–deck interactions for various ship motions. The code was structured by incorporating a vehicle model into a piece of ship motion calculation code. A series of time-domain simulations were conducted to evaluate vehicle securing. It was found that for a target ship consisting of a 6000-unit Ro-Ro vessel, vehicle securing is mainly influenced by the ship's rolling motions and is highly dependent on the wave height and loading conditions. It was suggested from the analysis that vehicles could be secured without being lashed in a large area of the ship in specific weather conditions and on some routes with less adverse sea states. However, it is still suggested that conventional lashing holes should be constructed on the deck because in severe sea states the cars will still need to be lashed. The limitations of the current investigations are also presented. The relevant research work was carried out at the Division of Ship Design and Engineering, Department of Shipping and Marine Technology, Chalmers University of Technology.