The gate assignment problem is an important operational issue (GAP) faced by airlines at airports. The assignment schedule has implications for efficiencies in passenger transfer, baggage transfer, towing of unassigned aircraft,... more
The gate assignment problem is an important operational issue (GAP) faced by airlines at airports. The assignment schedule has implications for efficiencies in passenger transfer, baggage transfer, towing of unassigned aircraft, scheduling of ground logistics such as fueling, aircraft cleaning, and other maintenance functions, and overall passenger satisfaction. This paper presents a model for assigning flights to gates at airports that maximizes the total preference value of the flight-gate assignments subject to a number of constraints. The problem is formulated as a zero-one linear programming model which has a strong underlying acyclic network structure. The efficiency of the model is demonstrated on data obtained from Air Canada for the Halifax International Airport. A problem with 61 flights and 14 gates is solved optimally using CPLEX in 25 seconds of CPU time.
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Research Interests:
ABSTRACT Vertically integrated fish processing firms with a fishing fleet are forever faced with the difficult problem of dispatching fishing effort in such a way so as to minimize the cost of landing plant requirements. This landed cost... more
ABSTRACT Vertically integrated fish processing firms with a fishing fleet are forever faced with the difficult problem of dispatching fishing effort in such a way so as to minimize the cost of landing plant requirements. This landed cost of fish is a direct function of the catch rates observed on the fishing grounds. Unfortunately, these catch rates are not known a priori. Fish scouting involves routing a trawler over a set of fishing grounds to sample catch rates. The data obtained are used to develop a profile of the expected performance of the fleet. These data are also used to dispatch the rest of the fishing fleet. In dispatching the scouting mission, the dispatcher must select a set of grounds to visit so as the maximize the value of the information obtained while respecting a budget or trip limit constraint. The value of the potential information depends on the species required at the plants, and the age of the current information on the state of catch rates on the various fishing grounds. We present a mathematical programming model to assist the dispatcher in coming up with the optimal mission for the scouting fleet. We demonstrate the model on a problem involving 15 fish stocks.
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Industrial fish-processing firms must operate against a backdrop of uncertainty in the demand for fish (the raw material) and uncertainty in the demand for final products. Integrated firms must dispatch a harvesting fleet to land required... more
Industrial fish-processing firms must operate against a backdrop of uncertainty in the demand for fish (the raw material) and uncertainty in the demand for final products. Integrated firms must dispatch a harvesting fleet to land required catch at one or more processing plants. Typically fishing trips for individual vessels last for up to two weeks. In planning harvesting schedules, the decision maker must take into account the impact of the uncertainties mentioned above. The purpose of this research is to gain insight into the effectiveness of rolling horizon planning as a mechanism for coping with uncertainty, and to establish the nature of the relationship between the length of the frozen and planning horizons and the expected annual costs of fishing plans. Such insight will be extremely valuable to fleet harvest planners who must attempt to minimize the landed cost of raw fish.Vertically integrated fish-processing firms must dispatch their fishing fleet to meet short-term or long-term requirements for raw fish at the various processing plants. Fleet harvesting activity must be planned against a backdrop of uncertain catch rates, fish quality, and demand. In this paper, we investigate the potential for using rolling horizon planning as a strategy for managing the impact of these uncertainties, particularly in catch rates. We study the impact of the length of the planning and frozen horizons on the cost performance of fishing fleet schedules. Results for several scenarios involving variable catch rates, variable demands, and alternative rolling/planning horizon combinations are presented.
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The multi-item batch sizing problem is common to both purchasing/supply and production environments. Given a forecasted set of demands or requirements for a variety of products, time-varying capacity constraints for the storage/production... more
The multi-item batch sizing problem is common to both purchasing/supply and production environments. Given a forecasted set of demands or requirements for a variety of products, time-varying capacity constraints for the storage/production facility, and ordering and carrying costs for each product, the objective is to determine the optimal batch sizes or order quantities for products that would minimize the sum of ordering and carrying costs while satisfying demand requirements and respecting capacity constraints. In this paper we examine three mathematical formulations for solving the problem. We compare the degree of computational effort required for each formulation to obtain optimal solutions on a variety of test problems. We do so using an off-the-shelf mixed integer programming (MIP) solver called CPLEX. Our results show that there is one formulation which dominates performance under all problem settings, suggesting that in solving the batch sizing problem in purchasing or prod...
The gate assignment problem is an important operational issue (GAP) faced by airlines at airports. The assignment schedule has implications for efficiencies in passenger transfer, baggage transfer, towing of unassigned aircraft,... more
The gate assignment problem is an important operational issue (GAP) faced by airlines at airports. The assignment schedule has implications for efficiencies in passenger transfer, baggage transfer, towing of unassigned aircraft, scheduling of ground logistics such as fueling, aircraft cleaning, and other maintenance functions, and overall passenger satisfaction. This paper presents a model for assigning flights to gates at airports that maximizes the total preference value of the flight-gate assignments subject to a number of constraints. The problem is formulated as a zero-one linear programming model which has a strong underlying acyclic network structure. The efficiency of the model is demonstrated on data obtained from Air Canada for the Halifax International Airport. A problem with 61 flights and 14 gates is solved optimally using CPLEX in 25 seconds of CPU time.
Research Interests:
Research Interests:
Purpose – The purpose of this research is to identify the competitive priorities of the manufacturing firms in their internationalization efforts. Design/methodology/approach – A structured questionnaire survey is conducted involving 569... more
Purpose – The purpose of this research is to identify the competitive priorities of the manufacturing firms in their internationalization efforts. Design/methodology/approach – A structured questionnaire survey is conducted involving 569 manufacturing firms in China. The competitive priority in internationalization efforts is gauged by combining the degree of emphasis of manufacturing firms on a certain factor over the past three
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ABSTRACT The selective travelling salesperson problem (STSP) involves determining a tour of maximal value over a set of cities subject to a tour length constraint. The problem has the characteristic that not all cities have to be visited.... more
ABSTRACT The selective travelling salesperson problem (STSP) involves determining a tour of maximal value over a set of cities subject to a tour length constraint. The problem has the characteristic that not all cities have to be visited. An integer formulation which combines permutation variables with flow variables is presented. An upper bounding scheme for the number of nodes visited in the final solution is used to reduce the size of the integer programme. The problem is solved using an off-the-shelf mixed-integer solver called CPLEX. Results demonstrating the usefulness of the bound are presented. The methodology is also applied to solve a 15-zone fisheries surveillance problem.
Research Interests: Information Systems, Marketing, Computer Science, Information Technology, Project Management, and 14 moreOperations Research, Production, Logistics, Management Science, Forecasting, Scheduling, Operational Research, Investment, Mathematical Sciences, Reliability, Location, Upper Bound, Communications Technology, and Travelling salesperson Problem
Abstract This paper presents two algorithms for solving a network-based formulation of the capacitated multi-item lot-sizing problem with backordering. We employ Lagrangian decomposition and Lagrangian relaxation techniques which exploit... more
Abstract This paper presents two algorithms for solving a network-based formulation of the capacitated multi-item lot-sizing problem with backordering. We employ Lagrangian decomposition and Lagrangian relaxation techniques which exploit the underlying ...
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Research Interests:
ABSTRACT Fishery surveillance on both of the Atlantic and Pacific coasts of Canada costs the Canadian taxpayer several millions of dollars annually. Few of these dollars are recovered through fines from successfully prosecuted cases... more
ABSTRACT Fishery surveillance on both of the Atlantic and Pacific coasts of Canada costs the Canadian taxpayer several millions of dollars annually. Few of these dollars are recovered through fines from successfully prosecuted cases involving fishery violations. Consequently, federal fishery surveillance programs are not self-supporting—they are subsidized. In order to reduce the cost of the program to the Canadian taxpayer, it is necessary to implement a cost-effective program which maximizes the deterrent effect of surveillance effort. In this paper we present a tactical linear programming for effectively allocating annual surveillance effort to monitor and control fishing activity, and to enforce fishery regulations in accordance with resource management plans and objectives for the offshore fishery. In particular, we focus on the Atlantic fishery. The tactical model determines on an annual basis, for each of the surveillance units, the amount of effort allocated to each fishery/fishing zone in each time period while maximizing effectiveness. Once the effort allocations are made, operational tasks which involve scheduling surveillance/patrol units on a short-term basis in accordance with the annual plan and current priorities must be completed. We demonstrate the potential use of the planning model.
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ABSTRACT Vertically integrated fish processing firms with a fishing fleet are forever faced with the difficult problem of dispatching fishing effort in such a way so as to minimize the cost of landing plant requirements. This landed cost... more
ABSTRACT Vertically integrated fish processing firms with a fishing fleet are forever faced with the difficult problem of dispatching fishing effort in such a way so as to minimize the cost of landing plant requirements. This landed cost of fish is a direct function of the catch rates observed on the fishing grounds. Unfortunately, these catch rates are not known a priori. Fish scouting involves routing a trawler over a set of fishing grounds to sample catch rates. The data obtained are used to develop a profile of the expected performance of the fleet. These data are also used to dispatch the rest of the fishing fleet. In dispatching the scouting mission, the dispatcher must select a set of grounds to visit so as the maximize the value of the information obtained while respecting a budget or trip limit constraint. The value of the potential information depends on the species required at the plants, and the age of the current information on the state of catch rates on the various fishing grounds. We present a mathematical programming model to assist the dispatcher in coming up with the optimal mission for the scouting fleet. We demonstrate the model on a problem involving 15 fish stocks.
Research Interests:
ABSTRACT Planning the activities of fish-processing firms takes place against a backdrop of significant uncertainty. Demand patterns, fish supply, harvesting rates, fish quality, and more, are all uncertain planning parameters. This paper... more
ABSTRACT Planning the activities of fish-processing firms takes place against a backdrop of significant uncertainty. Demand patterns, fish supply, harvesting rates, fish quality, and more, are all uncertain planning parameters. This paper presents a two-stage decision framework for assisting the planning of harvesting and marketing activities in integrated fish-processing firms. These firms operate under an enterprise allocation scheme which gives them quasi-property rights to specified quantities of fish in the sea. The first stage of the decision methodology addresses the aggregate use of the firm's resources and enterprise allocations over a 1 year planning horizon. The objective is to maximize potential net profit to the firm. First-stage decisions are subsequently used to set the parameters and boundaries for the second decision stage which deals with the dispatching of the firm's fishing fleet. The fleet must be dispatched in a manner which allows the actualization of first-stage decisions at minimum cost. Information obtained from the second stage is used to modify the first-stage decisions if necessary. Using a combination of real and fabricated data, we demonstrate how the framework would be implemented for a typical firm in the Canadian Atlantic groundfish industry.
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ABSTRACT The enterprise allocation scheme (EAS) was introduced in Canada in 1982. It allocates quotas to enterprises operating in the Atlantic fishing industry. These quasi-property rights allow the enterprises to fish, at their... more
ABSTRACT The enterprise allocation scheme (EAS) was introduced in Canada in 1982. It allocates quotas to enterprises operating in the Atlantic fishing industry. These quasi-property rights allow the enterprises to fish, at their discretion, a fixed quantity of the resource. By its design, the EAS attempts to alleviate the problems created by the previous system of allocation which simply determined a total allowable catch (TAC) for each stock, and sent the various enterprises, including single-vessel owners, scrambling for a share of the resource, thus creating a phenomenon called the ‘tragedy of the commons’. (The tragedy of the commons characterizes a situation in which the competitors maximize their capacity as a way of maximizing their share of a fixed resource, thereby creating an over-capacitated industry. In the Atlantic fishery, in several cases, the share of the resource that could be secured could not sustain a profitable livelihood. This resulted in bankruptcy for many enterprises.) Although the underlying philosophy of the EAS is potentially effective, the current process of assigning quotas is not particularly efficient. We propose a model which allows for a systematic approach to quota allocation. The model has several potential benefits both for the enterprises and the regulating body. We delineate the model in the context of the Atlantic groundfish industry. However, the principles are generalizable and therefore applicable to any fishery where quasi-property rights are allocated. We illustrate the potential of the model with an example.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Industrial fish-processing firms must operate against a backdrop of uncertainty in the demand for fish (the raw material) and uncertainty in the demand for final products. Integrated firms must dispatch a harvesting fleet to land required... more
Industrial fish-processing firms must operate against a backdrop of uncertainty in the demand for fish (the raw material) and uncertainty in the demand for final products. Integrated firms must dispatch a harvesting fleet to land required catch at one or more processing plants. Typically fishing trips for individual vessels last for up to two weeks. In planning harvesting schedules, the decision maker must take into account the impact of the uncertainties mentioned above. The purpose of this research is to gain insight into the effectiveness of rolling horizon planning as a mechanism for coping with uncertainty, and to establish the nature of the relationship between the length of the frozen and planning horizons and the expected annual costs of fishing plans. Such insight will be extremely valuable to fleet harvest planners who must attempt to minimize the landed cost of raw fish.Vertically integrated fish-processing firms must dispatch their fishing fleet to meet short-term or long-term requirements for raw fish at the various processing plants. Fleet harvesting activity must be planned against a backdrop of uncertain catch rates, fish quality, and demand. In this paper, we investigate the potential for using rolling horizon planning as a strategy for managing the impact of these uncertainties, particularly in catch rates. We study the impact of the length of the planning and frozen horizons on the cost performance of fishing fleet schedules. Results for several scenarios involving variable catch rates, variable demands, and alternative rolling/planning horizon combinations are presented.
Research Interests:
Research Interests:
... Todd A. Barnes Pritsker Corporation 8910 Purdue Road, Suite 500 Indianapolis, Indiana 46268 L. Leslie Gardner Pritsker Corporation 1305 Cumberland Avenue West Lafayette, Indiana 47906 ABSTRACT Production scheduling of a process... more
... Todd A. Barnes Pritsker Corporation 8910 Purdue Road, Suite 500 Indianapolis, Indiana 46268 L. Leslie Gardner Pritsker Corporation 1305 Cumberland Avenue West Lafayette, Indiana 47906 ABSTRACT Production scheduling of a process industry is a formidable task. ...
Research Interests: Finance, Logic, Industrial Relations, Production, Engineering Management, and 14 moreSimulation in language learning, Scheduling, Industrial Engineering, Stochastic processes, Simultaneous Localization and Mapping, Uncertainty, Manufacture, Production Scheduling, Throughput, Job shop scheduling, Continuous Flow, Boolean Satisfiability, Food Processing Industry, and Simulation Model
This article presents the idea that carnival and cultural festivals in general are powerful metaphors for leadership practice. Leadership theory is not culturally neutral; it is predicated on western cultural values. Organizations... more
This article presents the idea that carnival and cultural festivals in general are powerful metaphors for leadership practice. Leadership theory is not culturally neutral; it is predicated on western cultural values. Organizations operating in non-western environments seeking congruence between leadership practice and indigenous culture, should look to their own cultural festivals as potential models of practice. These festivals are often powerful models of leadership for engagement and mobilization.
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This article discusses the importance of evaluating the effectiveness of managers.
