Papers by Anantaram Balakrishnan
Production and operations management, Mar 11, 2024
Social Science Research Network, 2010
We explore how the structure of connections between members of a target population systematically... more We explore how the structure of connections between members of a target population systematically influences the time-path of diffusion of an innovation through that population. Using the formalisms of small world networks, we model the existence of potential connections between members of a target population, the mechanisms for the activation of connections, and the effect of an activation (i.e., whether it leads to an adoption). Our proposed Small-World Multiple Influence model nests the Bass model and the Non-uniform influence model, and allows us to decompose word-ofmouth effects, e.g., whether an innovation spreads due to strong collective influence of a small circle of family members and friends or through the strong influence of distant acquaintances. The model incorporates a stochastic network, enables aggregation of individual-level adoptions in a network into a population diffusion curve, and permits unbiased estimation of the parameters of an underlying social network from a population diffusion curve. We assess the validity and value of our model by using data from 35 new products introduced in the US, and from diffusion data for cell phone and Internet from several European countries. The results show that the proposed model outperforms the competing models on both theoretical and empirical criteria.
Social Science Research Network, 2022
American Journal of Mathematical and Management Sciences, 1987
Integrated facility location and vehicle routing models: Recent work and future prospects. A Bala... more Integrated facility location and vehicle routing models: Recent work and future prospects. A Balakrishnan, JE Ward, RT Wong American Journal of Mathematical and Management Sciences 7:11, 35-61, 1987. Facility location ...
Social Science Research Network, Nov 20, 2011
Resource flexibility is an important tool for firms to better match capacity with demand so as to... more Resource flexibility is an important tool for firms to better match capacity with demand so as to increase revenues and improve service levels. However, in service contexts that require dynamically deciding whether to accept incoming jobsand what resource to assign to each accepted job, harnessing the benefits of flexibility requires using effective methods for making these operational decisions. Motivated by the resource deployment decisions facing a professional service firm in theworkplace training industry, we address the dynamic job acceptance and resource assignment problem for systems with general resource flexibility structure, i.e., with multiple resource types that can each perform different overlapping subsets of job types. We first show that, for systems containing specialized resources for individual job types and a versatile resource type that can perform all job types, the exact policy uses a threshold rule. With more general flexibility structures, since the associated stochastic dynamic program is intractable, we develop and test three optimization-based approximate policies. Our extensive computational tests show that one of the methods, which we call the Bottleneck Capacity Reservation policy, is remarkably effective in generating near-optimal solutions over a wide range of problem scenarios. We also consider a model variant that requires dynamic job acceptance decisions but permits deferring resource assignment decisions until the end of the horizon. For this model, we discuss an adaptation of our approximate policy, establish the effectiveness of this policy, and assess the value of postponing assignment decisions.
RePEc: Research Papers in Economics, 1992
RePEc: Research Papers in Economics, 1991
RePEc: Research Papers in Economics, Nov 1, 1993
A Tactical Planning Model for Mixed-Model Electronics Assembly Operations. ... it is available, t... more A Tactical Planning Model for Mixed-Model Electronics Assembly Operations. ... it is available, there are three options: 1. Check below under "Related research" whether ... Center for Operations Research and Econometrics (CORE) in its series CORE Discussion Papers with number ...
RePEc: Research Papers in Economics, 1992
Growing demand, increasing diversity of services, and advances in transmission and switching tech... more Growing demand, increasing diversity of services, and advances in transmission and switching technologies are prompting telecommunication companies to rapidly expand and modernize their networks. This paper develops and tests a decomposition methodology to generate cost-effective expansion plans, with performance guarantees, for one major component of the network hierarchy-the local access network connecting customers to the local switching center. The model captures economies of scale in facility costs, and addresses the central tradeoff between installing concentrators and expanding cables to accommodate demand growth. By exploiting the special tree and routing structure of the expansion planning problem, our solution method integrates two major algorithmic strategies from mathematical programming-the use of valid inequalities, obtained by studying a problem's polyhedral structure, and dynamic programming, which can be used to solve an uncapacitated version of the local access network expansion planning problem. The computational results for three actual test networks demonstrate that this enhanced dynamic programming algorithm, when embedded in a Lagrangian relaxation scheme (with problem preprocessing and local improvement), is very effective in generating good upper and lower bounds: implemented on a personal computer, the method was able to generate solutions that are within 1.2 to 7.0% of optimality. In addition to developing a successful solution methodology for a practical problem, this paper illustrates the possibility of effectively combining decomposition methods and polyhedral approaches.
Social Science Research Network, 2010
Manufacturers are increasingly relying on third-party logistics service providers to distribute t... more Manufacturers are increasingly relying on third-party logistics service providers to distribute their products to retail stores. Fee tables, specifying how much to pay for each delivery based on weight and distance, are commonly used as the basis for compensating distributors for their delivery services. This paper proposes and applies an optimization model and methodology to help a large building-products manufacturer design an appropriate fee table for payments to its distributors for delivering products from regional distribution centers to retail stores. The model selects the weight and distance ranges and sets the fees for each combination of ranges, taking into account the distances and distribution of shipment weights to each store, so as to ensure adequate total compensation for each distributor while satisfying fee monotonicity and other requirements. Since our mixed integer programming model is difficult to solve using commercial solvers, we develop a tailored approach to obtain near-optimal solutions quickly. Specifically, we identify valid inequalities based on the problem’s special structure to strengthen the model formulation, and develop an optimization-based procedure, that solves related network flow problems, to generate a heuristic solution. When applied to actual data from the building products manufacturer, our composite solution method, combining cutting planes and heuristic, proved to be effective (yielding heuristic solutions that are within 1% of optimality) and generated substantial savings (of nearly 10%) over the current fee table.
Social Science Research Network, 2005
In some retail contexts, higher inventories not only improve service levels, but also stimulate d... more In some retail contexts, higher inventories not only improve service levels, but also stimulate demand by serving as a promotional tool (e.g., by increasing product visibility). Motivated by a building-products retailer's practice of stocking large quantities of products to stimulate demand, we study inventory management policies when demand is uncertain but increases with stocking quantity. For general inventory-dependent demand distributions, we characterize the profit-maximizing policy for a stochastic inventory model that extends the classical newsvendor setting. We contrast this integrated policy with two functionally-oriented approaches-a demand-driven policy that might represent marketing managers' view of inventories as a means for promoting products, and a critical fractile policy that reflects the traditional inventory management tradeoff between the costs of overage and lost sales. Our analysis provides insights regarding the structure of the optimal policy, and its relationship to the functional viewpoints. We prove that the optimal stocking quantity always exceeds the critical fractile solution, and can even exceed the demand-driven stocking quantity. Our analysis further shows that the functional orientations are complementary, with one policy performing well when the other fares poorly. By synthesizing the two functional approaches, the optimal stocking policy can achieve considerably higher profits than either functional policy. We also address the problem of jointly optimizing price and stocking quantity for demand-stimulating inventories by considering two alternative models for incorporating the dependence of demand on price-a distribution-lifting model and a multiplicative model. We show that the models permit sequential optimization of the price and stocking quantity decisions, and that ignoring demand stimulation results in a less-than-optimal stocking quantity.
Metal forming operations such as rolling, extrusion, and drawing offer many opportunities for ope... more Metal forming operations such as rolling, extrusion, and drawing offer many opportunities for operations improvement through better process understanding and improved planning practices. This paper addresses short and medium term planning issues in sheet, plate, and tube manufacturing operations. First, v^e identify certain distinctive characteristics-the inherent process flexibility, close interdependence between successive stages, and economies of scale-of metal forming operations, and identify the planning and performance tradeoffs. We argue that, just as product design plays a critical role in manufacturing of discrete parts, process planning has strategic importance in the metal forming context. To be successful, process planning must be closely coupled with process engineering efforts, and must simultaneously consider the facility's entire product mix. In contrast, current process engineering efforts are mainly reactive, focusing on fixing problems at individual operations...
Information technology (IT) is both the key enabler for future manufacturing enterprises and a tr... more Information technology (IT) is both the key enabler for future manufacturing enterprises and a transformer of organizations and markets. By reducing barriers to collaboration, compressing lead time, eliminating physical movement, and enriching decision-making, IT helps manufacturers achieve their goal of meeting customer needs better, quicker, and cheaper. The global reach and easy connectivity that information technology provides has fostered cooperation while increasing market competition, and heightened customer expectations. Advances in computer and communication technologies combined with rapid changes in organizations have also created new opportunities for exploiting information technologies in the entire product realization process. This paper explores these opportunities, and identifies promising directions for research and systems development. We first review important trends in organizations, markets, and information technologies— from increasing customer involvement and opportunistic organizational alliances to global reach and connectivity, enterprise integration, and virtualization. Adopting a process viewpoint of the product realization cycle, we translate these trends into high-impact IT applications in design and operations that offer rich potential for applied research and development. Underlying these applications are four broad classes of intelligent information processes—intelligent search, diagnosis and prognosis, collaboration, coordination, and negotiation, and understanding and learning. Software agents provide an ideal platform to implement these processes. Our goal is to synthesize streams of thought from many related disciplines in engineering, science, and management, and develop a framework for examining how information technologies can facilitate and influence manufacturing.
This paper addresses optimal job sequencing decisions for various classes of permutation flowshop... more This paper addresses optimal job sequencing decisions for various classes of permutation flowshops. We first describe a framework to classify flowshop scheduling problems based on the level of intermediate storage, job transfer mechanism, and objective function. We discuss the interrelationships between various flowshop models, develop a new slack-based lower bound for the total processing time of each machine, and describe an assignment-patching heuristic to generate effective job sequences. Our computational results show that, compared to previous approaches, the slack-based lower bound is effective when job processing times are random or have a trend, and the assignment-patching heuristic performs well for all models. By locally improving the heuristic solution using a two-exchange procedure, we are able to generate solutions that ai^e within 10 % from optimal for most scenarios.
New Directions for Operations Research in Manufacturing, 1992
Paradigms of decentralized and “on-line” control developed in the context of distributed computin... more Paradigms of decentralized and “on-line” control developed in the context of distributed computing systems will be relevant to distributed manufacturing systems of the future. In this paper, we explore certain aspects of decentralized task allocation in distributed systems using formal mathematical models and analyses to justify effective control strategies. We analyze two schemata for task allocation in distributed manufacturing systems modeled as stochastic processes. The first schema has to do with the selection of on-line policies for task assignment in distributed environments with the feature that the uncertainty in the status of machines can be removed by incurring query costs. In the second schema, optimal task allocation in the distributed batch processing model of the manufacturing system is resolved using techniques from Markov decision theory.
Uploads
Papers by Anantaram Balakrishnan