Aris Pagoropoulos

Flexibility and complexity: is it a trade-off?

The aim of this paper is to investigate the relationship between flexibility and complexity. A number of flexibility measurement approaches are presented and are connected with the flexibility types they address. A series of measures and methods for the analysis and assessment of static and dynamic complexity are provided. A new measure for the assessment of static complexity, based on network complexity, is introduced. The relationship between flexibility and complexity is investigated with the help of two sets of indicative, simple and yet realistic manufacturing systems.

Manufacturing systems complexity analysis methods review

In the globalised and interconnected market, demand fluctuation along with the requirements of high product quality, low cost, short lead time and high customisation may lead to an increase in manufacturing complexity. Over the past years, several methods, following different theories and approaches, have been proposed for the analysis of manufacturing complexity. In this paper, the concepts of a manufacturing system’s complexity are discussed. This study is a systematic and rigorous attempt to identify and synthesise the research done in the manufacturing systems’ complexity domain. Special emphasis is given to the approaches based on a theoretical analytical framework that provide a quantitative analysis of manufacturing systems complexity. These approaches and their applications to industrial problems are presented, classified and discussed.

Intelligent Scheduling for Manufacturing Systems: A Case Study

The aim of this paper is the presentation of a scheduling method, its implementation to a software system, and its application to a commercial refrigerator factory. The method employs the modeling of the factory’s resources and the assignment of the workload of the resources in a hierarchical fashion. The developed software system simulates the operations of the factory and provides a schedule for the manufacturing system’s resources. The system is integrated with a holistic virtual platform, namely Virtual Factory Framework that allows it to exchange data related to product, process, resources, and key performance indicators along with other software components also integrated with the Virtual Factory Framework. A set of digital scheduling experiments with data, coming from a real manufacturing system are conducted in order to validate the proposed method and the implemented system under different operational conditions.

Economic and Environmental Impact Trade-Offs Related to In-Water Hull Cleanings of Merchant Vessels

Merchant vessels are equipped with antifouling systems to prevent accumulation of marine organisms on the hull—a phenomenon known as fouling. In many cases, however, fouling accumulates and in‐water hull cleaning is required. Hull cleanings are part of a hull management scheme, and although they are an established practice, their associated environmental and economic trade‐offs and conflicts have remained largely unexplored. The purpose of this article is to quantitatively assess both economic and environmental impacts of hull management schemes on the operation of tanker vessels. After identifying induced and avoided costs and environmental impacts from the hull management system, we used both temporally and spatially distributed models to capture the degradation of the antifouling system as well as the global sailing profile of the vessels. Last, we analyzed how each of the modeled impacts varied with the frequency of hull cleanings within the hull management scheme. Our analysis revealed a convex relationship between the frequency of hull cleanings and fuel savings. The higher the frequency of hull cleanings, the less fuel savings can be achieved per cleaning. In terms of costs, from some point on the costs of the service are likely to offset the savings—especially if fuel prices are low. In regards to climate change, avoided emissions due to fuel savings are likely to outweigh the limited impacts from the service itself. Last, while ecosystem impacts from marine, terrestrial, and freshwater eco‐toxicity are likely to increase from hull cleanings, they are subject to high uncertainties.

Building an Ontology of Product/Service-Systems: Using a Maritime Case Study to Elicit Classifications and Characteristics

In recent years, the innovation strategy and development process entitled Product/Service-Systems (PSS), has attracted considerable attention from the research and industrial communities. The many contributions have come from various academic and professional viewpoints, which despite providing a rich view of PSS as a strategy, also leaves some confusion as to what actually constitutes a PSS. The definition of a PSS ontology could provide the basis for a more systematic knowledge gathering within the field and facilitate the application of integrated solutions within the industry. Ontologies provide an effective tool for a knowledge management process, due to their semantic capabilities, interoperability and extendibility. A PSS ontology for domain conceptualisation is proposed that captures the underlying end-user value and relates to existing PSS offerings. The PSS ontology is subsequently integrated into an ontology for the maritime sector, in order to allow for the identification of the PSS implementation opportunities within the industry. A maritime ontology can help the industry to document and reuse tacit knowledge while facilitating the implementation and value assessment of PSS solutions.

Life Cycle Costing: An Introduction

The chapter gives an introduction to life cycle costing (LCC) and how it can be used to support decision-making. It can form the economic pillar in a full life cycle sustainability assessment, but often system delimitations differ depending on the goal and scope of the study. To provide a profound understanding this chapter describes several approaches and terms, fundamental principles and different types of costs. A brief introduction is given to conventional LCC and societal LCC but the main focus is on environmental Life Cycle Costing (eLCC) as the LCC approach that is compatible with environmental Life Cycle Assessment (LCA) in terms of system delimitation. Differences are explained and addressed, and an overview is given of the main cost categories to consider from different user perspectives. As inventory data is often sensitive in financial analyses, a list of relevant databases is provided as well as guidance on how to collect data to overcome this hurdle. In an illustrative case study on window frames, the eLCC theory is applied and demonstrated with each step along the eLCC procedure described in detail. A final section about advanced LCC introduces how to monetarise externalities and how to do discounting.

The influence of costs and benefits' analysis on service strategy formulation: Learnings from the shipping industry

Abstract Although servitization as a transformation process is being recognized by an increasing number of firms as a source of competitive advantage, the role of economic evaluations in service strategy formulation has so far attracted limited attention – and predominantly from the manufacturer perspective. This paper assesses how the analysis of costs and benefits of Product-Service Systems (PSS) as servitized offerings influences the formulation of service strategies in the shipping industry. The study examines both the manufacturer and customer perspectives using two case studies from the shipping sector. Life Cycle Costing (LCC) was used as a tool to assess the associated costs and benefits of two proposed PSS. Based on the results of the LCC, the drivers and barriers of the actual transformation processes were explored through workshops and interviews served to map the perspectives of both manufacturers and customers. For both case studies the LCC revealed that, while the PSS resulted in a decrease in life cycle costs and a possible revenue opportunity, there was also a lack of fundamental demand for PSS that could complicate the formulation of service strategies. Towards formulating service strategies, the analysis of costs and benefits highlighted the importance of the abilities of both the customer and the manufacturer to deliver and implement a PSS. Moreover, the customer perspective highlighted the importance of internal functions and capabilities that allowed the customer to implement and benefit from service strategies.