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The Southern Giant Petrel (Macronectes giganteus (Gmelin, 1789); Aves, Procellariiformes), ranging from New Zealand to the Graham Peninsula and Patagonia and also from coastal Antarctica to Gough Island, displays significant geographic variation throughout its range. Six breeding provinces were identified, which show significant interpopulational variation. The formerly proposed subspecies Macronectes giganteus giganteus and Macronectes giganteus solanderi were confirmed. Macronectes giganteus solanderi has smaller homologuous parts than M. o Le Petrel geant meridional (Macronectes giganteus (Gmelin, 1789); Aves, Procellariiformes), dont la repartition s'etend de la Nouvelle-Zelande a la peninsule de Graham et la Patagonie, ainsi que de la cote de l'Antarctique a l'ile Gough, presente une variation geographique significative a travers toute son aire de repartition, compose de six provinces--des regions qui presentent une variation interpopulationnelle significative. Les deux sous-especes proposes anterieurement, Macronectes giganteus giganteus et Macronectes giganteus solanderi, sont confirm s doi: 10.1139/Z09-134, Introduction The Giant Petrel was once considered a single polymorphic species, Macronectes giganteus (Gmelin, 1789). Since the mid-1960s (Warham 1962; Bourne and Warham 1966; Voisin 1968), this taxon has been [...]

An exact solution method for the Discrete Lotsizing and Scheduling Problem (DLSPSD) with sequence dependent set-up times and set-up costs is developed, based on the conversion of DLSPSD into a Travelling Salesman Problem with Time Windows. It was established that the method is the first algorithm able to solve moderate DLSPD problems well with a moderate computational effort.

The failure of operations research (OR) panel sessions to lead to productive discussions or the generation of new ideas is analyzed. Experiences with a semi-plenary panel session on the challenges posed by OR practice organized during the EURO XIV Conference are used as reference. The disappointing outcomes of sessions are attributed to excessive focus on individual issues and failure to address root dilemmas.

Lower bounding procedures and upper bounding heuristics are shown to be effective in the capacitated distribution and waste disposal problem when these are embedded in a standard branch and bound algorithm. The problem involves the simultaneous design of a distribution network with plants and waste disposal units (WDU) and the coordination of product flows and waste flows within the network to minimize fixed costs for opening plants and WDUs as well as the variable costs related to product and waste flows.

Exact and approximation algorithms for solving the operational fixed interval scheduling problem (OFISP) are presented. The OFISP arises from the scheduling of several jobs, each of them with a fixed starting time, fixed ending time, priority index and job class, such that there is maximal total priority in the assignment of jobs to machines. The algorithms are effective because they address the job scheduling and task assignment aspects of OFISP.

Large oil companies or petroleum firms have substantial logistics problems related to their distribution networks. Operational costs can be minimized by the redesign of the firm's distribution systems. The redesign process can be accomplished by breaking down the systems into intermediate stages involving oil depot location and client assignment, cyclical delivery scheduling and route planning. Finally, a feedback mechanism can be integrated into the systems for information consistency to achieve minimal logistic costs.

This article examines strategic production and operations management issues in product recovery management (PRM). PRM encompasses the management of all used and discarded products, components, and materials for which a manufacturing company is legally, contractually, or otherwise responsible. The objective of PRM is to recover as much of the economic (and ecological) value of used and discarded products, components, and materials as reasonably possible, thereby reducing the ultimate quantities of wate to a minimum. This article also discusses the relevance of PRM to durable products manufacturers. It contains a categorization of PRM decisions. A case study based on the PRM system of a multinational copier manufacturer is presented to illustrate a set of specific production and operations management issues. The experiences of two other pro-active manufacturers (BMW and IBM) are also discussed. (Reprinted by permission of the publisher.)

The problem of planning product and by-product flows for minimal-cost distribution in a two-level network is considered. The problem concerns the optimal locations of processing facilities and post-processing plants for minimizing capital costs and the cost of transporting the product and its by-products. To facilitate a solution, four models based on upper bounding and lower bounding heuristics are developed.

A decision support system (DSS) has greatly contributed to the planning of the size and organization of the aircraft maintenance division of KLM Royal Dutch Airlines. Specifically, the airline company applied the DSS in determining the right number of maintenance engineers and their training needs and in assessing the efficacy of the department. The maintenance department, whose main asset is its manpower, is tasked with checking and maintaining airplanes while these are grounded at the airport.

Batching or lotsizing plays an important role in ensuring efficient and effective goods flow. It is defined as the process of clustering items for simultaneous transportation or manufacturing processing. Batching capitalizes on flexibility by encouraging the occurrence of company operations at the cost-service end. It applies theories and methods from operations research to develop systems that aid in the decision-making process involved in production and distribution.

A set partitioning heuristic for the generalized assignment problem, which is aimed at reducing the costs of assigning J jobs to M capacity constrained machines so that one job is assigned to just one machine, is proposed. The proposed heuristic is based on column generation methods and generates both upper and lower bounds. The heuristic can search for solutions that are on average within 0.13% from optimality.

A heurisitic for the solution of the Discrete Lotsizing and Scheduling Problem (DLSP) is developed and evaluated. DLSP involves finding a minimal cost production schedule that ensures demand fulfillment without backlogging. Such a schedule includes production batch sequencing and sizing for multiple units on a single machine. A dual ascent and column generation heuristic is proposed for the solution of the DLSP, which is reformulated into a set partitioning problem. Eighty-two percent of the 420 test problems were given optimal solutions through this method, with medium-sized problems requiring five minutes solution time. Relative to other models, the proposed framework is successful given that DLSP lends itself to polynomial solution when multi-item capacity contraints are relaxed, and that the method generates tight lower bounds.

Multilevel lotsizing is one of the most challenging subjects in production planning, especially in the presence of capacity constraints. In this paper we investigate lotsizing heuristics for assembly production systems with a bottleneck. More specifically, we discuss heuristics based on Linear Programming (LP), and compare the performance of these heuristics with the performance of approaches based on simulated annealing and tabu search techniques. A comparison of the three heuristics on a set of test problems shows that simulated annealing and tabu search perform well compared to pure LP-based heuristics, but the effectiveness of the latter heuristics can be improved by combining them with elements from simulated annealing and tabu search.

The effects of lead-time duration and variability on total expected costs in manufacturing/remanufacturing were investigated using the PUSH and PULL control strategies proposed by van der Laan et al (1995). It was shown that manufacturing lead-times exert more influence on system costs than remanufacturing lead-times for both control strategies. In addition, cost reduction may sometimes arise due a larger remanufacturing lead-time and a larger variability in the manufacturing lead-time.