Distributed optimization in transportation and logistics networks

Many important problems in communication networks, transportation networks, and logistics networks are solved by the minimization of cost functions. In general, these can be complex optimization problems involving many variables. However, physicists noted that in a network, a node variable (such as the amount of resources of the nodes) is connected to a set of link variables (such as the flow connecting the node), and similarly each link variable is connected to a number of (usually two) node variables. This enables one to break the problem into local components, often arriving at distributive algorithms to solve the problems. Compared with centralized algorithms, distributed algorithms have the advantages of lower computational complexity, and lower communication overhead. Since they have a faster response to local changes of the environment, they are especially useful for networks with evolving conditions. This review will cover message-passing algorithms in applications such as resource allocation, transportation networks, facility location, traffic routing, and stability of power grids.

The evolution of logistics service providers and the role of Internet-based applications in facilitating global operations

The need for global logistics services has increased dramatically and become extremely complex and dynamic as a result of a number of changes in manufacturing and in industrial production. In response, the logistics industry is changing in a variety of ways, including mergers to form integrated transportation service providers, outsourcing and increased use of information technology. The aim of this chapter is to provide an overview of the evolution and the most important trends in the logistics services provider (LSP) industry. Specific emphasis will be given to the role of Internet-based applications. Within this context, the chapter will also present the role of logistics e-marketplaces. In particular, based on the secondary research of currently existing logistics on-line marketplaces, an analysis and classification of them is provided with the aim of identifying service gaps. The analysis reveals that logistics electronic marketplaces, despite the increased range of services currently offered, still face limitations with reference to integrated customs links or translation services, which both reduce the efficiency of global operations.

An Investigation into Outsourcing Practice in Ireland:A New Direction in Logistics and Supply Chain Management

Companies are increasingly focusing on the development of core competencies as an integral part of their overall strategy development and implementation. The corollary of this is that functions regarded as being non-core are being outsourced. This paper investigates the case for and against outsourcing and in addition what is happening in Ireland regards outsourcing. Furthermore to analysis of current literature in the field, an Irish-wide postal and e-mail survey, as well as three case studies revealed many interesting facts. The key findings of the work are manufacturing outsourcing is now the most popular function to be outsourced for both small to medium sized enterprises (SMEs) and large enterprises. Large enterprises (LEs) do not prepare or examine hidden costs more than SMEs, nor do they differ much in relation to the use of consultants. Furthermore, the importance of time spent on preparing or producing contract, and the impact the contract can have on the supplier-buyer relation do not differ significantly. It was found that most companies outsourced within Ireland, which led to further investigation in that area. In relation to logistics outsourcing specifically, this has become very important in the supply chain over the last 20 years as an activity that was traditionally handled by firms as a support function. At that time logistics activities such as warehousing, distribution, transportation and inventory management were given low priority compared with other business functions within the organisation. However, since the customer has become more demanding, the logistics function has now become a source of competitive advantage and there has been a growing emphasis on providing good customer service.

Relationship between freight accessibility and logistics employment in US counties

This paper analyzes the relationship between freight accessibility and logistics employment in the US. It develops an accessibility measure relevant for logistics companies based on a gravity model. This allows for an analysis of the accessibility of US counties focusing on four different modes of transportation: road, rail, air, and maritime. Using a Partial Least Squares model, these four different freight accessibility measures are combined into two constructs, continental and intercontinental freight accessibility, and related to logistics employment. Results show that highly accessible counties attract more logistics employment than other counties. The analyses show that it is very important to control for the effect of the county population on both freight accessibility and logistics employment. While county population explains the most variation in the logistics employment per county, there is a significant relationship between freight accessibility and logistics employment, when controlling for this effect.