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The structure‐borne sound generated by power equipment can be isolated effectively through vibration absorber under hull base structures. The practical vibration isolation performance is limited due to the weight, size and cost. The dramatic attenuating wave propagation characteristic of hull base without adding weight is essential to the vessel acoustic stealth.

The characteristics of vibration wave propagated from typical shape base link structures have been investigated according to impedance mismatch and wave conversion in non‐homogeneous structure. The hull base is simplified to three degrees of freedom damped system through the mechanical impedance method. The influence of blocking mass weight, as well as location properties to the base vibration isolation performance have been discussed. Furthermore, the structure‐borne sound design of a typical hull base is carried out.

The impedance mismatch of the hull base is further increased by the comprehensive use of high transmission loss base link structures, blocking mass as well as damping layer. The effectiveness of structure‐borne sound design is verified through numerical calculation together with underwater model test. The test data show that the noise has been reduced larger than 3 dB.

The paper describes what is believed to be the first application of the high transmission loss base in hull structures based on the literature survey. The method of structure‐borne sound design of a typical hull base can be applied in different types of vessels.

Females with autism spectrum disorder (ASD) may display superficial social skills which may mask their ASD symptomology impacting on the identification of the disorder – known as the “camouflage” hypothesis. Compared to males with ASD, it is increasingly recognised that females with ASD have a stronger ability to imitate behaviour which is socially acceptable, particularly those females who have higher cognitive abilities (i.e. intelligence considered to be within the normal range) (Ehlers and Gillberg, 1993). The paper aims to discuss this issue.

This paper will explore the literature on camouflaging or masking behaviour in females with ASD. A systematic PRISMA review was conducted.

The capacity to “camouflage” social difficulties in social situations is considered to be one of the main features of the female phenotype of ASD (e.g. Kenyon, 2014). Social imitation or camouflaging enables some level of success and coping, which results in some females never receiving a diagnosis of ASD. They typically may not exhibit any observable functional impairments. However, under the surface of the camouflage, females may experience high levels of subjective stress, anxiety and exhaustion and a need to re-charge or recuperate by withdrawing from any social interaction.

There is relatively little understanding and knowledge of the female phenotype of ASD. This lack of understanding and knowledge impacts significantly on the ability to identify females with ASD (Lai et al., 2015; Bargiela et al., 2016), which can have a number of negative consequence (Adamou et al., 2018; National Collaborating Centre for Mental Health (UK), 2012).

There is a need for the development of a camouflaging measure.

There is a real need for further research exploring the positive and negative impact of the phenomenon of “camouflaging”, or “pretending to be normal” in females with ASD.

The purpose of the paper is to develop a method of automatic classification of the components of the assembly units. The method is crucial for developing an automatic ship assembly planning tools. The proposed method takes into account the assumptions specific for shipbuilding technology processes: high complexity of structures, difficult expert-based classification of components, fixed priority relations between connections resulting from geometrical constraints and demands of welding processes.

The set of ex post determined liaisons and assembly sequences constitutes the database of structures which have been made-up earlier. The components classification problem is solved using matrix coding of graphs. Information in such form is stored in the database. The minimization of number of cycles in the graph of classes sequence and minimization of diversity of classes within all constructions has been proposed as criteria of optimization. The genetic algorithm has been proposed as a solution method.

The proposed method solves the problem of components’ classifications. It allows setting the pattern of priorities between classes of various connections. This gives a chance to determine the relationship constraints between the connections of new structures for which assembly sequences are not established.

Mathematical formulation of the database is quite laborious. The possibility of partial automation of this process should be considered. Owing to the complexity of the problem, a relatively simple objective function has been proposed. During a ship hull assembly, additional criteria should be taken into account, what will be the direction of further research.

Automatic classification of components is dedicated for implementation in shipyards and similar assembly systems. Tests performed by the authors confirm efficiency of presented method in supporting management of the database and assembly of new structures planning. Suggested activity-oriented approach allows for easy conversion of any assembly unit structure to the form of a matrix.

The new approach for components classification according to its assembly features distinguishes the proposed method from others. The use of nilpotent matrix theory in an acyclicity of graphs analysis is also a unique achievement. Original crossover and mutation operators for assembly sequence were proposed in the article.

The purpose of this paper is computer-aided engineering analysis of the recently proposed side-vent-channel concept for mitigation of the blast-loads resulting from a shallow-buried mine detonated underneath a light tactical vehicle. The concept involves the use of side-vent-channels attached to the V-shaped vehicle underbody, and was motivated by the concepts and principles of operation of the so-called “pulse detonation” rocket engines. By proper shaping of the V-hull and side-vent-channels, venting of supersonically expanding gaseous detonation products is promoted in order to generate a downward thrust on the targeted vehicle.

The utility and the blast-mitigation capacity of this concept were examined in the prior work using computational methods and tools which suffered from some deficiencies related to the proper representation of the mine, soil, and vehicle materials, as well as air/gaseous detonation products. In the present work, an attempt is made to remove some of these deficiencies, and to carry out a bi-objective engineering-optimization analysis of the V-hull and side-vent-channel shape and size for maximum reduction of the momentum transferred to and the maximum acceleration acquired by the targeted vehicle.

Due to the conflicting nature of the two objectives, a set of the Pareto designs was identified, which provide the optimal levels of the trade-off between the two objectives.

To the authors’ knowledge, the present work is the first public-domain report of the side-vent-channel blast-mitigation concept.

The purpose of this paper is to develop the method of generating assembly sequences, which can be used in the shipbuilding industry. The method must take into account the assumptions specific for assembly processes of large-size steel ship hulls, among others, a large number of connections, multi-stage and parallel assembly, set priority relations between connections.

The assembly sequence is presented as a directed acyclic graph, whose vertices are mutually uniquely assigned to connections on a hull structure. The minimization of the number of unmet priority precedence of performing connections has been proposed as a criterion of optimization. The genetic algorithm has been proposed as a method to solve problems.

The proposed method allows to model the acyclic assembly process of welded structures and find solutions minimizing the objective function even for very complex problems. Because of this, the method has a chance to be used in shipbuilding.

Mathematical formulation of priority assumptions is quite laborious. The possibility of partial automation of this process should be considered. Due to the complexity of the problem, a relatively simplified objective function has been proposed. In assembling a hull, additional criteria should be taken into account. It is the direction of further research.

The method can be successfully used in shipbuilding and in planning the production of other steel welded structures, among others, tanks, components of bridges, offshore structures. Examples of calculations were performed on an actual structure of a hull fragment.

A new way of coding the acyclic serial-parallel sequence was designed. The proposed method allows to analyse the sequence using the graph theory. Original, two-part crossover and mutation operators for assembling sequence were proposed.

To investigate the effects of moisture and freeze‐thaw cycling on the absorption and flexural properties of rice‐hull‐polyethylene (PE) composite.

Various rice‐hull‐PE composite specimens were submerged in water at various temperatures and subjected to various freeze‐thaw cycles. Various characterisations including water absorption, bending strength and stiffness, Fourier transform infrared spectroscopy and scanning electron microscope imaging were performed.

High temperatures accelerated the water sorption of the rice‐hull‐PE composite and increased the equilibrium moisture content. The uncoated surface was not significantly more easily permeated than the coated surface, contrary to expectations. However, more water was absorbed from the cut surface than from the original extruded surface. This was attributed to the tiny checks left on the surface by the sawing action, which indicated the importance of protecting the original surface layer from scraping or other damage. Bending strength and stiffness of the rice‐hull‐PE composite decreased significantly after the freeze‐thaw cycling treatment. The modulus of elasticity decreased more than the modulus of rupture. Compared to the effect of water immersion alone, freeze‐thaw cycling treatment slightly accelerated this decrease.

The results of this study were obtained from accelerated laboratory experiments. Further research could be carried out to evaluate the properties of this rice‐hull‐PE composite in practical application.

The research revealed a possible degradation in quality when the rice‐hull‐PE composite is used in moist or freezing conditions. The resin layer on the extruded surface provides an important protection.

In China, rice‐hull powder is widely used as a reinforcing component in plastic composite. However, the durability of rice‐hull/PE composites has rarely been investigated. Results from this study will help users apply rice‐hull‐PE composites correctly and encourage the development of other agro‐fibre/polymer materials.

Recent technical developments in the field of hydrodynamic sustentation, resulting from the unique techniques associated with the free‐body testing of self‐propelled dynamically similar models, has resulted in a great resurgence of interest in the use of water‐based aircraft in the National Defence. This paper describes some of the more important aspects of this research and discusses possible trends in military water‐based aircraft development. In addition to the military applications of the new high‐speed hydrodynamic developments, consideration is given to the development of transonic water‐based transport designs. Since the days of the famous flying‐boat clippers, over‐ocean transport has all but succumbed to the faster landplane. It is shown that an all‐jet water‐based transport, incorporating unusual safety and performance, is now a practical and logical development.

Empty container repositioning is an important issue in the liner shipping industry. Generally stated, two groups of mathematical models have been proposed to tackle this issue. The first group aims to derive time‐dependent origin‐destination matrices that specify the number of empty containers to be repositioned at a decision epoch; the second group aims to develop effective state‐feedback control policies consisting of dynamic decision‐making rules. There is, however, a lack of research into the comparison of these two groups, especially with regard to realistic cases subject to uncertainties. The purpose of this paper is to evaluate and compare the performances of some typical repositioning policies from these two groups and to shed light on their relative merits and suitability in various realistic scenarios.

Based on a literature review, the paper classifies the current empty container repositioning policies into two categories: origin‐destination (OD) based solutions and state‐based dynamic rules. Typical policies are selected from these two categories and then evaluated using a simulation tool. A range of scenarios are designed based on realistic cases considering the stochastic and dynamic nature of liner services. A comprehensive set of simulation experiments are conducted and analysed; and the relative merits and suitability of the repositioning policies are identified.

Through a carefully designed comparative study, several research findings are obtained with regard to how the performances of different types of empty container repositioning policies are affected by various factors such as structure of service route, uncertainty of daily demands, and parametric optimisation methods.

The study makes a good attempt to analyse the suitability of different empty container repositioning policies in different scenarios. This is an area that has lacked investigation. The research findings can help shipping companies and other relevant stakeholders better understand the relative merits of different empty container repositioning policies and better tackle the challenges in operating the container shipping system.

It is usual when carrying out tank tests on seaplane models to include measurements of the change in attitude when pitching moments of different amounts are applied. The measurements are generally made over a range of speeds in the neighbourhood of three‐quarters of the take‐off speed, in the neighbourhood of one‐third of the take‐off speed, and also with the hull or floats at rest. Curves of attitude against speed, with different applied moments, are shown in Fig. 11, for a twin‐float seaplane, and may be regarded as typical.

This paper aims to investigate the different analytical methods used to predict the performance of seaplanes to define the weaknesses in each method and be able to extend the analytical approach to include the nonlinear terms (unsteadiness).

First, the elemental hydrodynamic characteristics of seaplanes are discussed. Second, five different analytical methods are reviewed. The advantages and disadvantages of each method are stated. After that, the heave and pitch equations of seaplane motion are illustrated. The procedure of obtaining the solution of the heave and pitch equations of seaplane motion is explained. Finally, the results obtained from the most common methods are compared.

The results show that the methods are based on different assumptions and considerations. As a result, no method is optimal for all types of seaplanes. Moreover, some of the analytical methods do not study the stability of the seaplane, which is a major issue in the design of seaplanes. In addition, all methods consider the motion as steady and linear. The objective is to extend the work to include the nonlinear effects.

This paper presents some of the analytical methods used in describing the performance of seaplanes and explains how can they be applied. Moreover, it summarises the advantages and disadvantages of each method.