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作者：TRICK, MA
摘要：We examine scheduling problems where we control not only the assignment of jobs to machines, but also the time used by the job on the machine. For instance, many tooling machines allow control of the speed at which a job is run. Increasing the speed incurs costs due to machine wear, but also increases throughput. We discuss some fundamental scheduling problems in this environment and give algorithms for some interesting cases. Some cases are inherently difficult so for these we give heuristics...
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作者：VRANAS, PB; BERTSIMAS, DJ; ODONI, AR
摘要：Motivated by the important problem of congestion costs (they were estimated to be $ 2 billion in 199 1) in air transportation and observing that ground delays are more preferable than airborne delays, we have formulated and studied several integer programming models to assign ground-holding delays optimally in a general network of airports, so that the total (ground plus airborne) delay cost of all flights is minimized. All previous research on this problem has been restricted to the single-ai...
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作者：RINGEL, EI; MODE, CJ
作者单位：Drexel University
摘要：This paper explores the application of stochastic process ideas to answer some fundamental questions about a state system which arises in the Mode Select Beacon System (Mode-S), an air-space management system. A Series of models is developed, based on semi-Markov processes, population models, and Monte Carlo simulation. Computer programs in the APL programming language to implement the models and to process the resulting data are developed. The output of the models illuminate the behavior of t...
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作者：POPKEN, DA
摘要：To remain competitive, manufacturers must seek transportation strategies that both reduce costs and maintain high levels of service. One approach is to consolidate inbound freight at transshipment points. This provides economies of scale and promotes capacity efficient mixes of high and low density items. When service level considerations are included via inventory holding costs, the approach yields a nonlinear network model with multiattribute multicommodity flows. The model is difficult to s...
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作者：ANILY, S; BRAMEL, J; SIMCHILEVI, D
作者单位：Columbia University
摘要：We consider the famous bin packing problem where a set of items must be stored in bins of equal capacity. In the classical version, the objective is to minimize the number of bins used. Motivated by several optimization problems that occur in the context of the storage of items, we study a more general cost structure where the cost of a bin is a concave function of the number of items in the bin. The objective is to store the items in such a way that total cost is minimized. Such cost function...
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作者：RAVI, SS; ROSENKRANTZ, DJ; TAYI, GK
摘要：The dispersion problem arises in selecting facilities to maximize som, function of the distances between the facilities. The problem also arises in selecting nondominated solutions for multiobjective decision making. It is known to be NP-hard under two objectives: maximizing the minimum distance (MAX-MIN) between any pair of facilities and maximizing the average distance (MAX-AVG). We consider the question of obtaining near-optimal solutions. For MAX-MIN, we show that if the distances do not s...
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作者：HIGLE, JL; LOWE, WW; ODIO, R
摘要：Simulation and optimization are among the most commonly used elements in the OR toolkit. Often times, some of the data elements used to define an optimization problem are best described by random variables, yielding a stochastic program. If the distributions of the random variables cannot be specified precisely, one may have to resort to simulation to obtain observations of these random variables. In this paper, we present conditional stochastic decomposition (CSD), a method that may be constr...
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作者：DADA, M; MARCELLUS, R
摘要：We study the control of a production process which moves at a random time from an in-control state to an out-of-control state where an increased number of defective units is produced. After each unit is produced, a decision maker has three choices: continue production, invest in routine maintenance that restores the process to control, and invest in a more expensive learn maintenance that, in addition, may decrease the tendency of the process to go out of control. The optimal policy structure ...
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作者：VEATCH, MH; WEIN, LM
作者单位：Massachusetts Institute of Technology (MIT)
摘要：A manufacturing facility consisting of two stations in tandem operates in a make-to-stock mode: After production, items are placed in a finished goods inventory that services an exogenous Poisson demand. Demand that cannot be met from inventory is backordered. Each station is modeled as a queue with controllable production rate and exponential service times. The problem is to control these rates to minimize inventory holding and backordering costs. Optimal controls are computed using dynamic p...
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作者：FU, MC
摘要：For (s, S) inventory systems, we derive sample path derivatives of performance measures with respect to the two Parameters s and S. These derivatives yield derivative estimators which can be estimated from a single sample path or simulation of the inventory system, in some cases not even requiring actual knowledge of the underlying demand distribution. Such derivative estimates would be useful in sensitivity analysis or in gradient-based optimization techniques. We consider the nondiscounted p...
