Combined quay crane assignment and quay crane scheduling with crane inter-vessel movement and non-interference constraints

Integrated models of the quay crane assignment problem (QCAP) and the quay crane scheduling problem (QCSP) exist. However, they have shortcomings in that some do not allow movement of quay cranes between vessels, others do not take into account precedence relationships between tasks, and yet others do not avoid interference between quay cranes. Here, an integrated and comprehensive optimization model that combines the two distinct QCAP and QCSP problems which deals with the issues raised is put forward. The model is of the mixed-integer programming type with the objective being to minimize the difference between tardiness cost and earliness income based on finishing time and requested departure time for a vessel. Because of the extent of the model and the potential for even small problems to lead to large instances, exact methods can be prohibitive in computational time. For this reason an adapted genetic algorithm (GA) is implemented to cope with this computational burden. Experimental results obtained with branch-and-cut as implemented in CPLEX and GA for small to large-scale problem instances are presented. The paper also includes a review of the relevant literature

An evolutionary approach to a combined mixed integer programming model of seaside operations as arise in container ports

This paper puts forward an integrated optimisation model that combines three distinct problems, namely berth allocation, quay crane assignment, and quay crane scheduling that arise in container ports. Each one of these problems is difficult to solve in its own right. However, solving them individually leads almost surely to sub-optimal solutions. Hence, it is desirable to solve them in a combined form. The model is of the mixed-integer programming type with the objective being to minimize the tardiness of vessels and reduce the cost of berthing. Experimental results show that relatively small instances of the proposed model can be solved exactly using CPLEX. Large scale instances, however, can only be solved in reasonable times using heuristics. Here, an implementation of the genetic algorithm is considered. The effectiveness of this implementation is tested against CPLEX on small to medium size instances of the combined model. Larger size instances were also solved with the genetic algorithm, showing that this approach is capable of finding the optimal or near optimal solutions in realistic times

Business Networks in Clusters and Industrial Districts. The governance of the global Value chain

During the 1980s the Marshallian concept of industrial district (ID) became widely popular due to the resurgence of interest in the reasons that make the agglomeration of specialized industries a territorial phenomenon worth being analyzed. The analysis of clusters and IDs has often been limited, considering only the local dimension of the created business networks. The external links of these systems have been systematically under-evaluated. This book offers a deep insight into the evolution of these systems and the internal-external mechanism of knowledge circulation and learning. This means that the access to external knowledge (information or R&D cooperative research) or to productive networks (global supply chains) is studied in order to describe how external knowledge is absorbed and how local clusters or districts become global systems. It provides a unified approach: showing that existing capabilities expand when locally embedded knowledge is combined with accessible external knowledge. In this view, external knowledge linkages reduce the danger of cognitive \u2018lock-in\u2019 and \u2018 over-embeddedness\u2019, which may become important obstacles to local learning and innovation when technological trajectories and global economic conditions chang

Evolution and relocation in fashion- led industrial districts: evidence from two case studies

The aim of this paper is to contribute to the debate about how, in advanced countries, industrial districts specialised in traditional manufacturing industries evolve as a consequence of new challenges linked to the globalization process. Using a multiple case study design, the study examines the evolution of two fashion-led Italian districts: the Montebelluna sportswear system and the Vibrata-Tordino-Vomano clothing district. Our findings reveal that cluster firms\u2019 ability to shift from manufacturing to other activities providing higher returns along the global value chain is key to understanding the effect of globalization and relocation processes on the cluster\u2019s long-term competitiveness. As illustrated in this study, weak learning districts are the most threatened while innovative districts are able to enact a selective process of relocation, substituting outplaced activities with more valuable ones and attracting inward investments. Keywords: industrial districts; evolution; relocation; global value chains

Industrial Districts, Relocation, and the Governance of the Global Value chain

The book builds on a conceptual framework that explores the reorganization of business networks in IDs&Cs along two dimensions. The two important flows under observation are: (1) the inflows/outflows of material resources and manufacturing activities; and (2) the inflows/outflows of knowledge. With reference to the first dimension, the wealth of experiences presented in this book shows that increasing global competition has generally resulted in the massive outflow of production activities from Western IDs&Cs through relocation. This is clearly documented in the contributions devoted to the analysis of three Italian industrial districts: the Montebelluna sportswear district (Chapter 5), the Vibrata Valley clothing district (Chapter 6), and the Verona footwear district (Chapter 4). However, as argued in the conceptual framework illustrated in Chapter 1, the effect of relocation on the industrial district\u2019s long-term sustainability differs depending on the possibility of using the international fragmentation of the district value chain as a means of fostering different forms of upgrading. In order to discriminate between the possible outcomes, Chapter 1 proposes a taxonomy of relocation strategies. In this regard, the theoretical implication that emerges from the reading of this book is that, whereas the analysis of global value chains has a significant capacity for explaining the possibilities of upgrading for the enterprises within them, its transposition to the cluster level needs to be carefully calibrated. Any cluster may indeed comprise different global and local value chains, with complex direct and indirect effects on the development of the cluster which cannot be deterministically defined. Outflows of manufacturing activities from Western IDs&Cs can potentially favour the formation of embryonic clusters in foreign countries. In this respect, Fiorenza Belussi (Chapter 9) and Simona Montagnana (Chapter 10) illustrate the experience of agglomeration of footwear firms in the region of Timisoara, in Romania. Although the outflow of production activities characterize the evolution of most Western industrial districts, the study conducted by Fiorenza Belussi and Silvia Sedita in the Arzignano leather-tanning district (Chapter 7) accounts for an opposite trend. This chapter provides an interesting example of \u2018inverse relocation\u2019, Business_Networks_01.indd xv 16/4/09 9:13:29 AM xvi Preface which involves \u2018transferring cheap labour\u2019 into Western IDs&Cs as an alternative to the relocation of manufacturing activities to low-labour-cost countries though international subcontracting and/or FDI. The second dimension explored in the book concerns the inflow and outflow of knowledge. Chapter 2 by Fiorenza Belussi and Silvia Sedita provides a conceptual elaboration on the learning processes that occurs in IDs&Cs based on the interaction between localized and distance learning. To capture the intertwined processes of knowledge generation and acquisition from local and external contexts the concept of \u2018learning at the boundaries\u2019 is introduced and discussed. The importance of this learning model is especially evident in high-tech industries, such as biotechnology, pharmaceuticals, telecommunication and aerospace, characterized by the complexity of the knowledge base required to foster innovation. The structure of these industries seems to conceal globalization and spatial agglomeration through a small worldwide pattern of connections: spatial agglomeration and interaction in local clusters is connected globally through the participation of local firms in distant inter-organizational networks thanks to various forms of formal and informal R&D collaborations. This dual geography emerges as a central theme also from the empirical studies collected in this book. In Chapter 16, concentrating on four regions in Germany, Fornahl and Tran explore the balance between local and external linkages and cooperative knowledge generation in the biotechnology industry. In Chapter 17, Asheim, Coenen and Moodysson investigate different forms of knowledge flows among actors in the Medicon Valley cluster by breaking down a number of innovation processes into concrete activities that are analyzed with regard to the spatial distribution of collaborators involve