Now showing items 1-16 of 16

    • The effect of economies-of-scale on the performance of lot-sizing heuristics in rolling horizon basis 

      Kian, R.; Berk, Emre; Gürler, Ülkü; Rezazadeh, H.; Yazdani, B. (Taylor and Francis, 2020)
      In this article, we consider the production planning problem in the presence of (dis)economies-of-scale in production costs on a rolling horizon basis with a fixed forecast horizon. We propose variants of three well-known ...
    • An exact analysis on age-based control policies for perishable inventories 

      Poormoaied, S.; Gürler, Ülkü; Berk, E. (Taylor and Francis, 01-09-2020)
      We investigate the impact of effective lifetime of items in an age-based control policy for perishable inventories, a so-called (Q, r, T) policy, with positive lead time and fixed lifetime. The exact analysis of this control ...
    • Hazard change point estimation 

      Gürler, Ülkü (John Wiley & Sons, 2006)
    • The impact of abusing return policies: a newsvendor model with opportunistic consumers 

      Ülkü, M. A.; Gürler, Ülkü (Elsevier, 2018)
      Consumers may return a product for a variety of reasons, such as the product having the wrong color or size, having poor functionality, being damaged during shipment, or simply prompting regret for an impulsive purchase. ...
    • An integrated replenishment and transportation model: Computational performance assessment 

      Kian, R.; Berk, Emre; Gürler, Ülkü (CRC Press, 2014)
    • Inventory theory 

      Gürler, Ülkü; Berk, Emre (Taylor & Francis, 2016)
      Inventory theory is concerned with management of the quantity and timing of the replenishment of assets typically stored to satisfy future demands. In this chapter, we introduce the fundamentals of inventory theory and the ...
    • Minimal conic quadratic reformulations and an optimization model 

      Kian, R.; Berk, Emre; Gürler, Ülkü (Elsevier, 2019)
      In this paper, we consider a particular form of inequalities which involves product of multiple variables with rational exponents. These inequalities can equivalently be represented by a number of conic quadratic forms ...
    • Newsboy inventory problem 

      Gürler, Ülkü; Berk, Emre (John Wiley & Sons, 2006)
      A definition and classical formulation of the newsboy inventory model as a profit maximization problem is provided. The structure of the optimal stocking policy is given. Alternative formulations of mean-variance, down-side ...
    • Newsboy inventory problem [reprint] 

      Gürler, Ülkü; Berk, Emre (John Wiley & Sons, 2010)
      A definition and classical formulation of the newsboy inventory model as a profit maximization problem is provided. The structure of the optimal stocking policy is given. Alternative formulations of mean-variance, down-side ...
    • Nonparametric bivariate estimation with randomly truncated observations 

      Gürler, Ülkü (Elsevier, 2003)
      This chapter focuses on the nonparametric estimation of the bivariate hazard and distribution functions (d.f.) when observations are subject to random truncation. Estimation of bivariate distribution and hazard functions ...
    • On the (Q,r) policy for perishables with positive lead times and multiple outstanding orders 

      Berk, Emre; Gürler, Ülkü; Poormoaied, Saeed (Springer New York LLC, 2020-01)
      We consider an inventory system for perishables with fixed lifetimes, positive replenishment lead times and lost sales in the presence of non-negligible fixed ordering costs. The system is studied under the lotsize reorder ...
    • On the consistency of a two-sample matching test 

      Gürler, Ülkü; Siddiqui, M. M. (Taylor & Francis, 1996)
      Let {X k} and {Y k}, 1 ≤ k ≤n be the order statistics of independent random samples from continuous distribution function F and G respectively. To test the null hypothesis H 0 : G = F, known, against the alternative H 1 : ...
    • Queueing theory 

      Gürler, Ülkü; Berk, Emre (CRC Press, 2016)
      Queueing theory is concerned with the quantitative modeling of dynamic systems that generate waiting lines, and the analysis of the behavior of such systems in the short and long time spans. In this chapter, we present a ...
    • Reverse Hazard 

      Gürler, Ülkü (John Wiley & Sons, 2006)
    • Reverse hazard 

      Gürler, Ülkü (Wiley, 2016)
      As a dual of the hazard rate function, reversed hazard rate characterizes the probability of an immediate past failure, given that a failure has already occurred. This function appears to be important both in survival and ...
    • Two-sample matching test 

      Gürler, Ülkü (John Wiley & Sons, 2006)