An approach using Lagrangian/surrogate relaxation for lot-sizing with transportation costs

Neste trabalho estuda-se um problema de dimensionamento de lotes e distribuição que envolve além de custos de estoques, produção e preparação, custos de transportes para o armazém da empresa. Os custos logísticos estão associados aos contêineres necessários para empacotar os produtos produzidos. A empresa negocia um contrato de longo prazo onde um custo fixo por período é associado ao transporte dos itens, em contrapartida um limite de contêineres é disponibilizado com custo mais baixo que o custo padrão. Caso ocorra um aumento ocasional de demanda, novos contêineres podem ser utilizados, no entanto, seu custo é mais elevado. Um modelo matemático foi proposto na literatura e resolvido utilizando uma heurística Lagrangiana. No presente trabalho a resolução do problema por uma heurística Lagrangiana/surrogate é avaliada. Além disso, é considerada uma extensão do modelo da literatura adicionando restrições de capacidade e permitindo atraso no atendimento a demanda. Testes computacionais mostraram que a heurística Lagrangiana/surrogate é competitiva especialmente quando se têm restrições de capacidade apertada.

Michigan intra-state motor transportation costs.

Mode of access: Internet.

Efficiency optimization of the transportation supply chain activity: the maritime option for Volkswagen Autoeuropa

Field Lab of Entrepreneurial Innovative Ventures

Endogenous transportation technology in a cournot differential game with intraindustry trade

We investigate a dynamic Cournot duopoly with intraindustry trade, where firms invest in R&D to reduce the level of iceberg transportation costs. We adopt both open-loop and closed-loop equilibrium concepts, showing that a unique (saddle point) steady state exists in both cases. In the open-loop model, optimal investments and the resulting efficiency of transportation technology are independent of the relative size of the two countries. On the contrary, in the closed-loop case firms’ R&D incentives are driven by the relative size of the two countries. Policy implications are also evaluated.

Transport costs, distance, and time : evidence from the Japanese Census of Logistics

Geographic distance is a standard proxy for transport costs under the simple assumption that freight fees increase monotonically over space. Using the Japanese Census of Logistics, this paper examines the extent to which transport distance and time affect freight costs across shipping modes, commodity groups, and prefecture pairs. The results show substantial heterogeneity in transport costs and time across shipping modes. Consistent with an iceberg formulation of transport costs, distance has a significantly positive effect on freight costs by air transportation. However, I find the puzzling results that business enterprises are likely to pay more for short-distance shipments by truck, ship, and railroad transportation. As a plausible explanation, I discuss aggregation bias arising from freight-specific premiums for timely, frequent, and small-batch shipments.

Transportation infrastructure impacts on firm location: the effect of a new metro line in the suburbs of Madrid

Firm location patterns emerge as a consequence of multiple factors, including firm considerations, labor force availability, market opportunities, and transportation costs. Many of these factors are influenced by changes in accessibility wrought by new transportation infrastructure. In this paper we use spatial statistical techniques and a micro-level data base to evaluate the effects of Madrid?s metro line 12 (known as Metrosur) expansion on business location patterns. The case study is the municipality of Alcorcon, which is served by the new metro line since 2003. Specifically, we explore the location patterns by different industry sectors, to evaluate if the new metro line has encouraged the emergence of a ?Metrosur spatial economy?. Our results indicate that the pattern of economic activity location is related to urban accessibility and that agglomeration, through economies of scale, also plays an important role. The results presented in this paper provide evidence useful to inform efficient transportation, urban, and regional economic planning.

Mobility of the elderly and handicapped: a methodology for evaluating the effectiveness of transportation improvements for the elderly and handicapped. Final report.

Transportation Department, Office of University Research, Washington, D.C.

The LIFT: special needs transportation in Portland, Oregon. Interim report.

Urban Mass Transportation Administration, Washington, D.C.

A guide to innovative financing mechanisms for mass transportation: an update. Revised edition.

Urban Mass Transportation Administration, Washington, D.C.

Transit in the nation's capital: what lies ahead? A study of projected transit service, costs, and financial impacts on the region through the year 2000. Final report.

Urban Mass Transportation Administration, Washington, D.C.

Special transportation services for the elderly and handicapped in Baton Rouge. Final report.

Transportation Systems Center, Cambridge, Mass.

Transportation programs for the elderly. Department of Health, Education and Welfare and other federal agencies.

Mode of access: Internet.

Cleveland neighborhood elderly transportation demonstration project. Final report.

Transportation Systems Center, Cambridge, Mass.

Transportation in America's future: potentials for the next half century. Part 1: societal context. Final report.

Transportation Department, Washington, D.C.