Addressing Complexity Aspects in Conceptual Ship Design: A Systems Engineering Approach

This article approaches the complexity aspects of conceptual ship design from a systems engineering point of view. We introduce the issue by defining the term complexity in systems engineering, placing the conceptual ship design task as a complex system problem and creating analogies between generic complex systems and a ship. Five main aspects of complexity are presented, linking challenges of the conceptual phase to each of the aspects. The structural aspect is related to the arrangement and interrelationship of the physical objects in the ship. The behavioral aspect derives from the form-function mapping. The external circumstances to which the ship is subjected are approached through the contextual aspect. Uncertainties in the scenarios and changes over time are related to the temporal aspect. The perceptual aspect relates to how stakeholders perceive the value that they receive from a chosen design. A theoretical study to address these five aspects is presented, applying the responsive systems comparison method in the conceptual design of an anchor handling a tug supply vessel. The last section discusses why decomposing the complexities of the ship design task in five aspects is a benefit.

BACKGROUND: Understanding how and why the development of conceptual ship designs sometimes become ineffective is essential for ship design firms. Our proposition is that in many projects, uncertainty influences negatively the effectiveness of the decision-making process. OBJECTIVE: The objective of this article is to quantify the perception of uncertainty in conceptual ship design processes. METHODS: In this article, we propose a research model to study such a phenomenon. The research model is tested using multivariate regression analysis, building on a survey conducted among 23 shipping companies. RESULTS: Our model suggests that 14% ( R 2 ) of the variability in the effectiveness of decision-making processes in ship design can be explained by changes in the perception of uncertainty. We can extract three interesting insights from this research work for the ship design practitioners as to how to improve the effectiveness of their design processes: (i) put more effort into the contextual factors affecting the ship design process, (ii) improve the communication with vessel owners and other stakeholders, and (iii) improve the agility of the design process. CONCLUSIONS: This study contributes to research on uncertainty in ship design processes by: (a) proposing an investigative model, (b) developing and testing a survey instrument and (c) running a multivariate regression analysis to study the effect of perceived uncertainty on the effectiveness of decision-making processes in conceptual ship design.

This paper presents a method of applying a memory-based learning (MBL) technique to automatic building of an indexing scheme for accessing reference cases during the conceptual design phase of a new ship. The conceptual ship design process begins with selecting previously designed reference ships of the same type with similar sizes and speeds. These reference ships are used for deriving an initial design of a new ship, and then the initial design is kept modified and repaired until the design reaches a level of satisfactory quality. The selection of good reference ships is essential for deriving a good initial design, and the quality of the initial design affects the efficiency and quality of the whole conceptual design process. The selection of reference ships has so far been done by design experts relying on their experience and engineering knowledge of ship design and structural mechanics. We developed an MBL method that can build an effective indexing scheme for retrieving good reference cases from a case base of previous ship designs. Empirical results show that the indexing scheme generated by MBL outperforms those by other learning methods such as the decision tree learning.

The paper covered a study aimed at developing a risk-based conceptual ship design method for bulk carriers, while taking into account the life cycle assessment and energy efficiency of the ship propulsion system. The study included conceptual ship design as a part of the risk-based ship design approach. In such conceptual design, using the long-time experience and statistics, the main dimensions and hull form, resistance and propulsion, weights, initial stability, freeboard, seakeeping and manoeuvrability were initially derived and the capital expenditure, operational expenditure, and decommissioning expenditure obtained. An optimal design solution was obtained, based on the energy efficiency design index, shipbuilding, operation, and resale costs at the end of the service life, which were used as input variables in a riskbased analysis.

The complexity of problems facing society continues to grow, and decision-makers and problem-solvers are finding many of today's emerging problems to be beyond their capability to adequately address. There is agreement in the literature that problems of this nature are complex system problems, inextricably linked to some highly complex system of systems. Establishing a clear understanding of the specific complex system context is fundamental to the process of understanding and analyzing complex systems and complex system problems across all of the different systems-based disciplines. While complex system context is widely referred to in systems literature, there is no clear characterization of exactly what system context is, making this foundational system concept ambiguous. This research addressed this gap in the systems body of knowledge by providing the needed detail and clarity to the concept of complex system context. A rigorous research methodology, employing the grounded theory method, was used to analyze data collected through a series of semi-structured interviews conducted with individuals reflecting a wide range of systems education and practical experience. Two research questions were identified as integral to increasing the understanding of context within complex systems. (1) What are the constituent elements of complex system context, and what attributes and dimensions characterize these elements? (2) What systems-based framework can be developed for constructing and articulating complex system context? Using the grounded theory method, a theory of system context was constructed, adding to the systems body of knowledge and substantiating a comprehensive and unambiguous theoretical construct for system context within complex systems. Then, based on this theory, a conceptual model to articulate and capture system-specific complex system context was developed---the Complex System Contextual Framework (CSCF). The CSCF shows significant promise for contribution to systems practitioners by supporting the future development of tools to help practitioners capture system context as a part of complex system problem formulation. The research also made a contribution in the area of research methodologies by furthering the use of the grounded theory method in the engineering management and systems engineering domain, an area where its application has been very limited.

The present paper provides a thorough analysis of the prerequisites in adopting a new paradigm in the conceptual ship design accounting for the environmental pollution driven by maritime transportations. A survey of presently issued IMO environmental requirements outlines the framework within ship design solutions. Identified and carefully examined are several competing optimal design solutions, based on the energy efficiency design index introduced for shipbuilding, operation cost, and the resale costs at the end of the service life, which are used as input variables in a risk-based analysis. Reviewed are the immediate steps taken in the risk-based conceptual ship design to minimise the risk of environmental pollution while considering the life cycle assessment and energy efficiency of the ship propulsion system. Brought forth in the current paper are the results of a study into the concept design of series of containerships operating in the Black Sea for transporting 20, 40 and 45-foot containers aimed at identifying the main dimensions, capacity, visibility, freeboard, stability, bow, and stern design, propulsion complex and propeller design, control and manoeuvrability, seakeeping, energy efficiency design index, capital, and operational expenditures, that leads to the required fright rate for the ships in the range of 4,000 to 14,000 DWT. Accordingly, a bulk carrier’s risk-based concept ship design methodology is employed for the ship life cycle assessment and energy efficiency in pursuance of the optimal design solution in reference to the energy efficiency design index as most applicable to shipbuilding, operation, and resale costs at the end of the service life, and used as input variables in the risk estimate.

ABSTRACTThe present Navy planning procedure is not well suited for successful development of non‐conventional, advanced naval ships. This paper highlights the key problems and recommends some solutions.In the early stages of concept design of the advanced naval ship, many of the key ship parameters, as well as cost ceilings, become arbitrarily set and frozen. Mission analysis, which should be done at the earliest stage of designing the ship, is often performed after‐the‐fact or is pro forma, and its results are often ignored. Thus, they do not impact ship design. Typically, considerations of hull and propulsion dominate, while the ship's proposed combat system and concepts of operations, which may ultimately make or break the ship program, are ignored or relegated to second class status. In many cases, combat system configuration selected does not exploit the unique performance capabilities of the ship. Consequently, the resulting ship has limited military utility and does not usually stand up well in a comparison with conventional ships on the basis of effectiveness, cost and risk. Furthermore, program justification to Navy, OSD and Congressional Reviewing Authorities is shaky.This paper proposes that mission analysis be done in parallel with ship concept design by a balanced team of ship designers, systems analysts, and weapon system engineers. By using mission analysis at the earliest stages of the design process, this team can make a number of “trade‐offs” between ship parameters and weapon/sensor performance leading to the definition of a suitable ship and an effective combat system. These “trade‐offs” should be performed with the objective of attaining highest military effectiveness at minimum cost. Ultimate military effectiveness should never be compromised merely to achieve some exotic ship performance capability. Since high military effectiveness for the advanced ship will result synergistically from the combination of the appropriate weapon or sensor that can capitalize on the unique performance capabilities of the ship, a way must be found to develop those few needed weapon and sensor systems. That way is beset by many organizational and management problems inherent in the Navy's R&D process. Nevertheless, if derived and supported by mission analysis, a detailed set of weapon/sensor performance requirements can be defined. These requirements should be entered into the RDT&E process but must continually be justified and defended along with the advanced ship until completion of their parallel development. Demonstrations of key prototype weapon/sensor systems should be conducted on prototype ships, which should be designed and built in parallel.The advanced ship planner must give greater recognition to the importance and contribution of properly integrated and effective combat system to his overall ship concept. This recognition of the need for high military effectiveness at lowest cost will lead to small displacement ship designs that have greater percentages of their total‐ship cost devoted to the combat system—as opposed to hull and propulsion—than is current U. S. Navy practice. This approach could best assure a highly effective, yet moderate cost, advanced naval ship.

Handling complexity in conceptual ship design processes requires a thorough understanding of complexity aspects in general. More than 100 scientific papers on the subject published since 1962 are, therefore, reviewed and discussed in this paper. The paper expands the understanding of complexity theory by reviewing the literature in the engineering domain. Different definitions of complexity, characteristics of complex systems, aspects of complexity in design, complexity sources, and its drivers are explored and discussed in detail. Furthermore, the findings are arranged into relevant complexity factors in ship design. Related complexity factors in ship design, are also discussed by use of examples from everyday ship design practices. This study is a theoretical elaboration to shed light on the current practice and future research direction in handling complexity in conceptual ship design processes to improve competitiveness.

A particle swarm optimization (PSO) solver is developed based on theoretical information available from the literature. The implementation is validated by utilizing the PSO optimizer as a driver for a single discipline optimization and for a multicriterion optimization and comparing the results to a commercially available gradient based optimization algorithm, previously published results, and a simple sequential Monte Carlo model. A typical conceptual ship design statement from the literature is employed for developing the single discipline and the multicriterion benchmark optimization statements. In the main new effort presented in this paper, an approach is developed for integrating the PSO algorithm as a driver at both the top and the discipline levels of a multidisciplinary design optimization (MDO) framework which is based on the Target Cascading (TC) method. The integrated MDO/PSO algorithm is employed for analyzing a multidiscipline optimization statement reflecting the conceptual ship design problem from the literature. Results are compared to MDO analyses performed when a gradient based optimizer comprised the optimization driver at all levels. The results, the strengths, and the weaknesses of the integrated MDO/PSO algorithm are discussed as related to conceptual ship design.

This paper presents some fundamental processes related to design inference and knowledge acquisition in the context of shipbuilding. Key categories of existing knowledge relevant for conceptual design are identified and classified. Alternative strategies for making this knowledge operable in a conceptual design context are discussed.

An approach to case-based system for conceptual ship design assistant

This paper applies the system-based ship design (SBSD) method to the conceptual design of a deep-sea mining vessel. The anticipated mine site is situated on the Norwegian extended continental shelf, where three production scenarios are assessed. The design process is documented, including a problem statement, mission description, functions, space requirements of various sub-systems, stability calculations, and preliminary cost estimates. A combination of data from existing technologies and estimates is used to set the relevant parameters, and the applicability of SBSD in the conceptual design of novel vessels is discussed. We find that when data is lacking in conceptual ship design, inspiration can be found from similar systems in established maritime industries, such as the offshore oil and gas industry.

In this paper an optimization based decision support model for determining diesel electric machinery system configuration in conceptual ship design is presented. Load distribution on the engines is considered in the model to ensure that required demand is met with sufficient power supply for all future operational states. A method for fuel consumption calculation is presented, based on determining optimal load distribution amongst the engines related to each engines generalized specific fuel consumption curve. Total fuel costs and appropriate NOX taxes are calculated based on the ship's future operational profiles. A case study is presented to exemplify the use of the model. Results show that the model might be used to obtain valuable insight to expected operational costs and decision support for selecting machinery system configuration.

The ship design activity often requires handling and storage of large amounts of data related to different systems inside the vessel, demanding for a structured way to organize it. This article suggests an objectoriented approach to handle virtual prototyping data during conceptual ship design. We start presenting some of the basic concepts related to objects, such as name, property and value. A proposal based on the entity, state and process models is addressed for the virtual prototyping, related to the object-oriented approach. Later, we use the SFI group system as hierarchy structure to represent the ship as an entity and state model. We finish by presenting some simple examples of the proposed approach with a modular ship models and introducing one suggestion of a virtual prototyping model using the concepts presented thorough the paper.

Years of volatile shipping market dynamics have intensified the need for more effective handling of uncertainty in conceptual and basic ship design processes. More recently, necessary climate remedial efforts in shipping have revealed the complexity associated with the facts-based selection of proper “green” technologies and ship design solutions, the control of their resulting extra costs and operational and commercial consequences. Naval architects and marine engineers and their ship design firms or shipyard affiliations, more than ever, have seen their expertise, knowledge, work practices, toolboxes and business concepts challenged - to the extent of capacity limits and perhaps beyond? Thus, the development of more advanced tools, more effective business concepts and efficient work procedures becomes increasingly important. Improved design processes must come, hand-with-hand, with new and refreshed expertise. This paper builds on the premise that uncertainty and complexity influence the effectiveness of the decision-making process in ship design. We argue, therefore, that to improve the way daily ship design activities are carried out it is necessary to better understand the influence of uncertainty and complexity on such transactions and to implement methods and tools to eliminate or reduce the associated detrimental effects on design quality and efficiency. The purpose of this paper is to explore, contrast, discuss and provide quantitative facts as to what are these inherent uncertainties and complexities and how do they influence effective decision making relating to conceptual ship design approaches and their design firms’ competitiveness. This complementary research work combines, summarizes and reports the research findings from two recent finalized PhD Thesis; Effectiveness in Decision-Making in Ship Design under Uncertainty and Handling Ship Design Complexity to enhance Competitiveness in Ship Design. The research work is well-grounded in the systems theory paradigm and this paper presents its results in the form of specific ways in which a revised systemic ship design approach can help ship designers and their firms to better handle uncertainty and complexity in their future dealings with a dynamic market situation and immature “greening” technologies based on the findings in the PhD Thesis.