263 research outputs found

    The application of multi-objective robust design methods in ship design

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    When designing large complex vessels, the evaluation of a particular design can be both complicated and time consuming. Designers often resort to the use of concept design models enabling both a reduction in complexity and time for evaluation. Various optimisation methods are then typically used to explore the design space facilitating the selection of optimum or near optimum designs. It is now possible to incorporate considerations of seakeeping, stability and costs at the earliest stage in the ship design process. However, to ensure that reliable results are obtained, the models used are generally complex and computationally expensive. Methods have been developed which avoid the necessity to carry out an exhaustive search of the complete design space. One such method is described which is concerned with the application of the theory of Design Of Experiments (DOE) enabling the design space to be efficiently explored. The objective of the DOE stage is to produce response surfaces which can then be used by an optimisation module to search the design space. It is assumed that the concept exploration tool whilst being a simplification of the design problem, is still sufficiently complicated to enable reliable evaluations of a particular design concept. The response surface is used as a representation of the concept exploration tool, and by it's nature can be used to rapidly evaluate a design concept hence reducing concept exploration time. While the methodology has a wide applicability in ship design and production, it is illustrated by its application to the design of a catamaran with respect to seakeeping. The paper presents results exploring the design space for the catamaran. A concept is selected which is robust with respect to the Relative Bow Motion (RBM), the heave, pitch and roll at any particular waveheading. The design space is defined by six controllable design parameters; hull length, breadth to draught ratio, distance between demihull centres, coefficient of waterplane, longitudinal centre of floatation, longitudinal centre of buoyancy, and by one noise parameter, the waveheading. A Pareto-optimal set of solutions is obtained using RBM, heave, pitch and roll as criteria. The designer can then select from this set the design which most closely satisfies their requirements. Typical solutions are shown to yield average reductions of over 25% in the objective functions when compared to earlier results obtained using conventional optimisation methods

    Multi-objective robust concept exploration within the made-to-order sector

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    Concept exploration is an activity of fundamental importance when designing large, complex made-to-order engineering products. At the concept design stage of the design process, it is essential that many design alternatives are evaluated. In the case of large made-to-order products, the evaluation of a particular design can be both complicated and time consuming. Under these circumstances, designers often resort to the use of concept design models enabling both a reduction in complexity and time for evaluation. Stochastic optimisation methods are then typically used to explore the design space facilitating the selection of optimum or near optimum designs. These optimisation methods can however increase the concept exploration time considerably due to their often random search manner. The objective of this work is therefore to produce a generic framework that would enable a designer to efficiently explore the design space within the MTO domain facilitating the selection of robust designs

    DecMS : an approach to providing decision support within NEC delivery

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    Decision-making across the military capability lifecycle phases can vary considerably in terms of the types of decisions made and the manner in which they are made. Although decision-making has received considerable attention within the research community, much work has concentrated on providing decision support for particular styles of decision-making. However, within capability delivery there is a need to develop approaches that can both map styles of decision-making to particular decision problems, and provide decision support at an executable level of detail. This paper presents the Decision Management and Support (DecMS) approach to providing decision support during capability delivery. The approach is based upon refining a fundamental model of decision-making to an executable level of detail. Refinement is controlled using analogical reasoning to ensure that the model is refined in accordance with the needs of the decision problem at hand. Future work will involve testing the effectiveness of the approach

    Behavioural Finance, Options Markets and Financial Crises: Application to the UK Market 1998-2010

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    Behavioural Finance, Options Markets and Financial Crises: Application to the UK Market 1998-2010 By Ian Alan Whitfield Abstract This thesis examines the relationship between behavioural finance and options markets. Particular focus is on the analysis of option prices, implied volatility and trading activity which in turn provides insights into predictability, momentum and overreaction. The thesis is contextualised by a general to specific evaluation of the literature that forms the basis of the behavioural finance paradigm. The review is extended to analyse the extent to which support for the behavioural finance approach has been produced by research on options. Behavioural finance retains an element of controversy as it runs counter to a key pillar of neoclassical finance, the efficient markets hypothesis. Hence the onus is on researchers in this field to produce evidence that refutes the notion of market efficiency and to build models with testable implications that are better able to capture the mechanics of financial markets. This thesis is motivated by a desire to investigate, in detail, key aspects of human behaviour and to test whether they are particularly apparent in options markets. It is important to study the information which can be extracted from options data and to analyse whether this has any predictive power for spot prices. By extension, it is of further interest to examine whether movements in spot prices exert influence on option prices. In particular, aspects of options that capture human behaviour such as pricing of puts relative to calls, implied volatility, trading volume and open interest. The topical relevance of the work is highlighted by thorough application to the UK market during two recent periods of intense financial turbulence; the bursting of the dotcom bubble in 2001 and the liquidity/banking crisis of 2007/8. The empirical work examines the pricing of exchange-traded options relative to theoretical values, the forecasting performance of implied volatility indexes, the ability of trading volume and open interest to capture behavioural aspects of trading behaviour, and momentum and overreaction effects. Hence the work provides a unique and thorough investigation into behavioural finance and options markets in the UK. Results indicate an important role for investor sentiment although they do not necessarily indicate exploitable inefficiencies

    Operational design co-ordination : an agent based approach

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    Operational design co-ordination has been identified as the basis for an approach to engineering design management that is more comprehensive than those that currently exist. As such, an integrated and holistic approach to operational design co-ordination has been developed that enables design to be managed in a coherent, appropriate and timely manner. Furthermore, the approach has been implemented within an agent-based software system, called the Design Co-ordination System, which has been applied to an industrial case study involving the computational design analysis of turbine blades. This application demonstrates that managing and adjusting in real-time in an operationally co-ordinated manner enables reductions in the time taken to complete the turbine blade design process to be achieved

    A design view of capability

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    In order to optimise resource deployment in a rapid changing operational environment, capability has received increasing concerns in terms of maximising the utilisation of resources. As a result of such extant research, different domains were seen to endow different meanings to capability, indicating a lack of common understanding of the true nature of capability. This paper presents a design view of capability from design artefact knowledge perspective. Capability is defined as an intrinsic quality of an entity closely related to artefact behavioural and structural knowledge. Design artefact knowledge was categorised across expected, instantiated, and interpreted artefact knowledge spaces (ES, IsS, and ItS). Accordingly, it suggests that three types of capability exist in the three spaces, which can be used in employing resources. Moreover, Network Enabled Capability (NEC), the capability of a set of linked resources within a specific environment is discussed, with an example of how network resources are deployed in a Virtual Integration Platform (VIP)

    An integrated decision support environment for organisational decision making

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    Traditional decision support systems are based on the paradigm of a single decision maker working at a stand-alone computer or terminal who has a specific decision to make with a specific goal in mind. Organisational decision support systems aim to support decision makers at all levels of an organisation (from executive, middle management managers to operators), who have a variety of decisions to make, with different priorities, often in a distributed environment. Such systems are designed and developed with extra functionality to meet the challenge. This paper proposes an Integrated Decision Support Environment (IDSE) for organisational decision making. The IDSE is designed and developed based on distributed client/server networking, with a combination of tight and loose integration approaches for information exchange and communication. The prototype of the IDSE demonstrates a good balance between flexibility and reliability

    A multi-agent based system to enable strategic and operational design coordination

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    This paper presents two systems which individually focus on different aspects of design coordination, namely strategic and operational. The systems were developed in parallel and individually contain related models that represent specific frames from a Design Coordination Framework developed by Andreasen et al. [1]. The focus of the strategic design management system is the management of design tasks, decisions, information, goals and rationale within the design process, whereas the focus of the operational design coordination system is the coordination of tasks and activities with respect to the near-optimal utilisation of available resources. A common interface exists which enables the two systems to be integrated and used as a single system with the aim of managing both strategicand operational design coordination. Hence, the objective of this work is to enable the design process to be conducted in a timely and appropriate manner

    Coordination approaches and systems - part II : an operational perspective

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    This is the second of two papers surveying research in coordination approaches and systems. This paper is concerned with operational coordination, which is aimed at coordinating activities such that the design process can be performed in a near optimal manner with respect to time, and the allocation and utilisation of resources. Aspects of coordination categorised as operational include resource management, scheduling and planning. The first of these two papers presents a review of coordination from a strategic perspective, which is concerned with the decision management aspects of coordination. Greater emphasis is now being placed on the significance of organising the design process as this affects time to market, product quality, cost, and consequently product success. The aim of this paper is to present a fundamental review of operational coordination approaches and systems. The 1990s has seen much progress being made towards a greater understanding and appreciation of coordination in various disciplines through the development of a wide range of approaches and systems. However, there remains a requirement to formally identify the key issues involved in coordination such that a widely accepted representation can be agreed upon. Consequently, research should continue to be supported in the exploration for a unified approach to coordination which will permit a broader and greater understanding of those aspects involved

    Knowledge re-use for decision support

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    Effective decision support has already been identified as a fundamental requirement for the realisation of Network Enabled Capability. Decision making itself is a knowledge-intensive process, and it is known that right decisions can only be reached based on decision maker's good judgement, which in turn is based on sufficient knowledge. It is not unusual for decision makers to make incorrect decisions because of insufficient knowledge. However, it is not always possible for decision makers to have all the knowledge needed for making decisions in complex situations without external support. The re-use of knowledge has been identified as providing an important contribution to such support, and this paper considers one, hitherto unexplored, aspect of how this may be achieved. This paper is concerned with the computational view of knowledge re-use to establish an understanding of a knowledge-based system for decision support. The paper explores knowledge re-use for decision support from two perspectives: knowledge provider's and knowledge re-user's. Key issues and challenges of knowledge re-use are identified from both perspectives. A structural model for knowledge re-use is proposed with initial evaluation through empirical study of both experienced and novice decision maker's behaviour in reusing knowledge to make decisions. The proposed structural model for knowledge re-use captures five main elements (knowledge re-uers, knowledge types, knowledge sources, environment, and integration strategies) as well as the relationships between the elements, which forms a foundation for constructing a knowledge-based decision support system. The paper suggests that further research should be investigating the relationship between knowledge re-use and learning to achieve intelligent decision support
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