Concept Studies for a Joint Support Ship

While all the major NATO navies have been under considerable pressure to downsize following the end of the post-Cold War, the higher degree of political instability world-wide has led to a desire to increase the deployability of the reduced number of naval assets. Thus there has been an increased interest in providing a new generation of naval support vessels as part of each navy’s contribution to Coalition peacekeeping. These new support ships are often also required to provide a contribution to amphibious capabilities, including humanitarian tasks, in littoral operations. This means there is a challenging combination of capabilities being sought from the current replacements of traditional afloat support ships. This paper describes the design work undertaken by the Design Research Centre at UCL, as part of a bid team responding to a Canadian National Defence Department requirement for feasibility studies into a “Joint Support Ship” programme. The UCL task consisted of designing a range of possible design options, to investigate the impact of capabilities on the configuration of this innovative concept, exploring the requirement’s two levels of capability, namely, “shall” and “should” as part of designing to cost and capability. A range of concepts was designed using the UCL Design Building Block approach, using the SURFCON module of the Graphics Research Corporation PARAMARINE ship design system. The advantage this approach gave in designing these novel solutions is shown through the ability of the DBB concept approach to balance both technical and configurational features, thereby enabling significantly different ship styles to be readily produced and compared

Seeing arrangements as connections: The use of networks in analysing existing and historical ship designs

A growing trend in computer aided ship design, particularly in the early stages, is the utilisation of approaches and numerical methods developed in other disciplines. Examples include genetic algorithms, financial methods of risk assessment and the use of network science. Networks can provide an abstract mathematical representation of many types of connected features, properties and information, such that the associated network analysis metrics and approaches can offer new ways of investigating and evaluating ship designs. This paper reports on ongoing UCL investigations into the application of network science in assisting human analysis of the general arrangements of existing ship designs. This work includes designs of complex service vessels (research vessels) as a comparison with naval ships and makes use of freely available network analysis software. This project makes use of the experience in naval vessel concept design at UCL by enabling a comparison of expert judgement and interpretation of designs with the quantitative network metrics. This paper describes the network analysis approach adopted, the findings for the arrangements analysed, and also discusses the future work required to further the approach

Modelling the operational effects of deploying and retrieving a fleet of uninhabited vehicles on the design of dedicated naval surface ships

Uninhabited vehicles (UXVs) are becoming an important component of naval warfare, providing an entirely new capability. By projecting military power in a more affordable way, through the use of UXVs, exposure of human life to military threats should be significantly reduced. While several navies are employing UXVs for a variety of applications, the concept of operating a fleet of such vehicles from a mothership that supports their overall operations during a mission, is a further challenge. This paper describes the research conducted by University College London (UCL) Design Research Centre (DRC) to develop and demonstrate a relevant analytical approach to design a mothership supporting a fleet of UXVs. This research should provide ship designers with the basis for early stage assessment of the impact of the various facilities seen as appropriate to host and support a substantial fleet of UXVs. It is particularly focused on the Launch and Recovery (LAR) capability of the UXV mothership. The research explored various options to demonstrate the proposed approach, rather than producing a definitive mothership design solution. This was appropriate given the fact that any UXV fleet composition is hard to predict (since mission related) and UXV technology is rapidly developing, so both must be speculative. It was found that the QT tool could provide meaningful investigation into the impact of potential tasks to be undertaken by a fleet of UXVs, addressing the design of mission bays, which were shown to be key to USV mothership design. While more focused simulations could refine subsystem options, this was not pursued, given the technology is still developing. Consequently, at this very early stage of investigating the deployment of a fleet of USVs from surface ships (through case studies), queuing network theory was seen to be more appropriate than a simulation-based analysis for this initial exploratory and investigatory work on future naval deployment of UXVs

Distributed Ship Service Systems Architecture in The Early Stages of Designing Physically Large and Complex Vessels: The Submarine Case

In the initial sizing of complex vessels, where recourse to type ship design can be overly restrictive, one crucial set of design features has traditionally been poorly addressed. This is the estimation of the weight and space demands of the various Distributed Ship Services Systems (DS3), which include different types of commodity services beyond those primarily associated with the ship propulsion system. In general, naval vessels are typified by extensive and densely engineered DS3, with the modern naval submarine being at the extreme of dense outfitting. Despite this, the ability for the concept designer to consider the impact of different configurations for the DS3 arrangements has not been readily addressed in concept design. This paper describes ongoing work at University College London (UCL) to develop a novel DS3 synthesis approach utilising computer tools, such as Paramarine™, MATLAB®, and CPLEX®, which provide the concept designer with a quantitative network-based evaluation to enable DS3 space and weight inputs early in the design process. The results of applying the approach to a conventional submarine case study indicate quantitative insights into early DS3 sizing can be obtained. The paper concludes with likely developments in concluding the research study

On the p,qp,q-binomial distribution and the Ising model

A completely new approach to the Ising model in 1 to 5 dimensions is developed. We employ $p,q$-binomial coefficients, a generalisation of the binomial coefficients, to describe the magnetisation distributions of the Ising model. For the complete graph this distribution corresponds exactly to the limit case $p=q$. We take our investigation to the simple $d$-dimensional lattices for $d=1,2,3,4,5$ and fit $p,q$-binomial distributions to our data, some of which are exact but most are sampled. For $d=1$ and $d=5$ the magnetisation distributions are remarkably well-fitted by $p,q$-binomial distributions. For $d=4$ we are only slightly less successful, while for $d=2,3$ we see some deviations (with exceptions!) between the $p,q$-binomial and the Ising distribution. We begin the paper by giving results on the behaviour of the $p,q$-distribution and its moment growth exponents given a certain parameterization of $p,q$. Since the moment exponents are known for the Ising model (or at least approximately for $d=3$) we can predict how $p,q$ should behave and compare this to our measured $p,q$. The results speak in favour of the $p,q$-binomial distribution's correctness regarding their general behaviour in comparison to the Ising model. The full extent to which they correctly model the Ising distribution is not settled though.Comment: 51 pages, 23 figures, submitted to PRB on Oct 23 200

Foraging time and temperature affected birth timing of Rhinolophus ferrumequinum and predicted year-to-year changes in a population in West Wales. U.K.

Movements of Rhinolophus ferrumequinum in and out of the nursery roost at Stackpole were monitored automatically from 1994 to 2018 with simultaneous measurements of roost and external air temperatures. Pups were counted manually in June–July and mean birth dates calculated. Maximum foraging times of the population between 16.00 h and 08.00 h and temperatures at midnight showed three types of activity. These types of activity explained why warmer springs were followed by earlier birth dates. When April was warmer the number of degree days, linked to the activity of night-flying insects, was higher so the maximum foraging times were longer. Hence, mean birth dates were earlier due to faster gestation. The indirect effect of degree days on the birth date, measured by the partial regression coefficient (ß = -0.321), was weaker than the direct effect (ß = - 0.628) and the mediating effect of maximum foraging time was significant (p < .001). During May-June and June-July bats foraged mainly from dusk to dawn so there was little variation in the maximum foraging times of the population, and it did not significantly mediate the effect of temperature on birth date. Birth dates were later when the external temperatures in June-July were higher (ß = 0.309), but the effect was small (R2 = 9.5%). Path analysis further revealed that longer maximum foraging times of the population in April predicted the year-to-year changes in the number of births and subsequently the number of adult females. Maximal foraging times of the population in April were a major influence on birth timing and ultimately determined whether the population grew or declined