International Journal of Production Research

Special issue dedicated to Suresh Sethi on the occasion of his 80th birthday

Background and objectives:
Suresh Sethi has made outstanding contributions to operations research and the management sciences. Specifically, his work has focused on topics in operations management, marketing, financial engineering, economics, and optimal control. These contributions have been recognized by Fellow awards from INFORMS, POMS, IEEE, SIAM, AAAS, NYAS (New York Academy of Sciences), and The Academies of Arts, Humanities, and Sciences of Canada (a.k.a, The Royal Society of Canada) as well as two international conferences held in his honor for his 60th birthday, and two edited books in his honor. We dedicate this special issue (SI) to Suresh Sethi on the occasion of his 80th birthday.

His noteworthy contributions to various topics specified above could be classified into several major sub-areas in operations research and the management sciences. Among these, Suresh Sethi has been working on the new area of inventory models with incomplete information or partial observations and has established himself as a leading authority in the area (Bensoussan et al. 2007a, 2007b, 2010). Sethi has made sustained contributions in extending the reach of the classical base stock and (𝑠,𝑆) policies to a variety of important problems in inventory management. These include problems with Markovian demands, forecast updates, multiple delivery modes, generalized assumptions on demands and cost functions, and information delays in both the discounted and average cost settings (Sethi 1984, Sethi and Cheng 1997, Sethi et al. 2003, Feng et al. 2006, Bensoussan et al. 2016, Perera and Sethi 2023a,b). Furthermore, his work on decision, forecast, and rolling horizons has provided a logical foundation for the practice of finite horizon assumptions and the choice of horizon (Sethi and Chand 1981, Bes and Sethi 1988, Sethi and Chutani 2024).

Two decades ago, the extant supply chain management literature had not addressed the realistic issue of coordination in supply chains involving risk-averse agents. Gan, Sethi, and Yan (2004, 2005) took up the challenge and began by defining a coordinating contract as one that results in a Pareto-optimal solution acceptable to each agent. Their definition generalizes the standard one in the risk-neutral case. Moreover, almost all of the research in supply chain coordination is devoted to the single-period setting, so it becomes extremely vital to extend the paradigm to the dynamic framework. In this regard, Li, Sethi, and He (2015) consider a decentralized multi-period supply chain and formulate it as a dynamic Stackelberg game.
In 1983, Sethi developed and solved a new stochastic dynamic advertising model, known now as the Sethi Advertising Model, or simply the Sethi Model. This model, now reported in numerous papers, has facilitated a variety of extensions in the literature that involve competition and marketing channels, resulting in non-cooperative game and cooperative supply chain settings, respectively (Bass et al. 2005, Naik et al. 2008).

Suresh Sethi is also the key figure in developing optimal control theory to address dynamic stochastic problems in operations management and supply chain management (Dolgui et al. 2018). His asymptotic optimality results, beginning with the seminal paper of Lehoczky, Sethi, Soner, and Taksar (1991), gave rise to a new theory of near-optimal decision-making in complex multi-time scale manufacturing systems.

Considering recent advances in these research areas and new challenges therein, the International Journal of Production Research is pleased to call for papers on various topics related to inventory management, manufacturing systems, operations and supply chain management, and the interface of operations and marketing. Theoretical contributions that significantly advance the related fields and those that align with Suresh Sethi’s work will be considered for publication. The guest editors invite authors to submit such papers to this SI. Authors are also reminded to consider the interests of the journal’s readers as well as to focus on the advanced techniques utilized by Sethi’s celebrated papers over his career. In particular, stochastic models will be preferred while innovative deterministic models could still be considered for publication. Submissions may address but are not limited to, the following topics, which highlight some of the key research areas of Suresh Sethi’s contributions over the years.

• Inventory models with incomplete information
• Inventory problems with Markovian demand and multi-delivery modes
• Decision, forecast, and rolling horizons in operations management
• Supply chain management and coordination
• Hierarchical production planning in multi-time scale stochastic manufacturing systems
• Dynamic advertising models
• Optimal control theory and its applications in the above research areas

References:
Bass, F. M., Krishnamoorthy, A., Prasad, A., Sethi, S.P. 2005. Generic and brand advertising strategies in a dynamic duopoly, Marketing Science, 24(4), 556–568.
Bensoussan, A., Çakanyildirim, M., Sethi, S.P. 2007a. A multiperiod newsvendor problem with partially observed demand, Mathematics of Operations Research, 32(2), 322–344.
Bensoussan, A., Çakanyildirim, M., Sethi, S.P. 2007b. Economic evaluation of systems that expedite inventory information, Production and Operations Management, 16(3), 360–368.
Bensoussan, A., Çakanyildirim, M., Sethi, S.P. 2010. Filtering for discrete-time Markov processes and applications to inventory control with incomplete information. The Oxford Handbook on Nonlinear Filtering, D. Crisan and B. Rozovskii (Eds.), Oxford University Press, 500–525.
Bensoussan, A., Feng, Q., Luo, S., Sethi, S. P. 2016. Evaluating long-term service performance under short-term forecast updates. International Journal of Production Research, 54(17), 5236–5249.
Bes, C., Sethi, S.P. 1988. Concepts of forecast and decision horizons: Applications to dynamic stochastic optimization problems, Mathematics of Operations Research, 13(2), 295–310.
Dolgui, A., Ivanov, D., Sethi, S. P., Sokolov, B. 2018. Scheduling in production, supply chain and Industry 4.0 systems by optimal control: fundamentals, state-of-the-art and applications. International Journal of Production Research, 57(2), 411–432.
Feng, Q., Sethi, S.P., Yan, H., Zhang, H. 2006. Are base-stock policies optimal in inventory problems with multiple delivery modes? Operations Research, 54(4), 801–807.
Gan, X., Sethi, S.P., Yan, H. 2004. Coordination of supply chains with risk-averse agents, Production and Operations Management, 13(2), 135–149.
Gan, X., Sethi, S.P., Yan, H. 2005. Channel coordination with a risk-neutral supplier and a downside-risk-averse retailer, Production and Operations Management, 14(1), 80–89.
Lehoczky, J.P., Sethi, S.P., Soner H., Taksar, M.I. 1991. An asymptotic analysis of hierarchical control of manufacturing systems under uncertainty, Mathematics of Operations Research, 16(3), 596–608.
Li, T., Sethi, S.P., He, X. 2015. Dynamic pricing, procurement, and channel coordination with stochastic learning, Production and Operations Management, 24(6), 857–882.
Perera, S. C., Sethi, S. P. 2023. A survey of stochastic inventory models with fixed costs: Optimality of (𝑠,𝑆) and (𝑠,𝑆) -type policies—Discrete-time case. Production and Operations Management, 32(1), 131–153.
Perera, S. C., Sethi, S. P. 2023. A survey of stochastic inventory models with fixed costs: Optimality of (𝑠,𝑆) and (𝑠,𝑆) -type policies—Continuous-time case. Production and Operations Management, 32(1), 154–169.
Naik, P.A., Prasad, A., Sethi, S.P. 2008. Building brand awareness in dynamic oligopoly markets, Management Science, 54(1), 129–138.
Sethi, S. P. 1984. A quantity discount lot size model with disposals. International Journal of Production Research, 22(1), 31–39.
Sethi, S.P., Chand, S. 1981. Multiple finite production rate dynamic lot size inventory models, Operations Research, 29(5), 931–944.
Sethi, S.P., Cheng, F. 1997. Optimality of (𝑠,𝑆) policies in inventory models with Markovian demand, Operations Research, 45(6), 931–939.
Sethi, S. P., Chutani, A. 2024. Forecast and decision horizons in a commodity trading model. International Journal of Production Research, 62(1–2), 245–259.
Sethi, S.P., Yan, H., Zhang, H. 2003. Inventory models with fixed costs, forecast updates, and two delivery modes, Operations Research, 51(2), 321–328.