Now showing items 1-20 of 758

    • 4-generated pseudo symmetric monomial curves with not Cohen–Macaulay tangent cones 

      Şahin, Nil (TUBITAK, 2020)
      In this article, standard bases of some toric ideals associated to 4-generated pseudo symmetric semigroups with not Cohen-Macaulay tangent cones at the origin are computed. As the tangent cones are not Cohen-Macaulay, ...
    • Accounting for parameter uncertainty in large-scale stochastic simulations with correlated inputs 

      Biller, B.; Corlu, C. G. (Institute for Operations Research and the Management Sciences (I N F O R M S), 2011)
      This paper considers large-scale stochastic simulations with correlated inputs having normal-to-anything (NORTA) distributions with arbitrary continuous marginal distributions. Examples of correlated inputs include processing ...
    • Accurate calculation of hazardous materials transport risks 

      Kara, B.; Erkut, E.; Verter, V. (Elsevier, 2003-07)
      We propose two path-selection algorithms for the transport of hazardous materials. The algorithms can deal with link impedances that are path-dependent. This approach is superior to the use of a standard shortest path ...
    • An adaptive bayesian replacement policy with minimal repair 

      Gürler, Ü.; Dayanık, S. (Institute for Operations Research and the Management Sciences (INFORMS), 2002)
      In this study, an adaptive Bayesian decision model is developed to determine the optimal replacement age for the systems maintained according to a general age-replacement policy. It is assumed that when a failure occurs, ...
    • Adjusted hazard rate estimator based on a known censoring probability 

      Gürler, Ü.; Kvam, P. (Taylor & Francis, 2011)
      In most reliability studies involving censoring, one assumes that censoring probabilities are unknown. We derive a nonparametric estimator for the survival function when information regarding censoring frequency is available. ...
    • Advances in business analytics at HP laboratories 

      Beyer, D.; Clearwater, S.; Chen, K. Y.; Feng, Q.; Huberman, B. A.; Jain, S.; Jamal, Z.; Şen, Alper; Tang, H. K.; Tarjan, B.; Ward, J.; Zhang, A.; Zhang, B. (Springer, Boston, 2010)
      HP Labs’ Business Optimization Lab is a group of researchers focused on developing innovations in business analytics that deliver value to HP. This chapter describes several activities of the Business Optimization Lab, ...
    • Age-based vs. stock level control policies for a perishable inventory system 

      Tekin, E.; Gürler Ü.; Berk, E. (2001)
      In this study, we investigate the impact of modified lotsize-reorder control policy for perishables which bases replenishment decisions on both the inventory level and the remaining lifetimes of items in stock. We derive ...
    • Aircraft and passenger recovery during an aircraft’s unexpected unavailability 

      Aktürk, M. Selim; Yeti̇moğlu, Y. N. (Elsevier, 2020-11-14)
      Airlines design their initial schedules under the assumption that all resources will be available on time and flights will operate as planned. However, some disruptions occur due to mechanical failures and unexpected delays ...
    • Aircraft recovery model with flight time controllability 

      Akturk, Mehmet Selim; Atamturk, A.; Gurel, S. (2011)
      [No abstract available]
    • Aircraft rescheduling with cruise speed control 

      Aktürk, M. S.; Atamtürk, A.; Gürel, S. (Institute for Operations Research and the Management Sciences (I N F O R M S), 2014-05-23)
      Airline operations are subject to frequent disruptions typically due to unexpected aircraft maintenance requirements and undesirable weather conditions. Recovery from a disruption often involves propagating delays in ...
    • An algorithm and a core set result for the weighted euclidean one-center problem 

      Kumar, P.; Yıldırım, A. E. (Institute for Operations Research and the Management Sciences (I N F O R M S), 2009)
      Given a set A of m points in n-dimensional space with corresponding positive weights, the weighted Euclidean one-center problem, which is a generalization of the minimum enclosing ball problem, involves the computation of ...
    • An algorithmic proof of the polyhedral decomposition theorem 

      Akgül, M. (John Wiley & Sons, 1988)
      It is well‐known that any point in a convex polyhedron P can be written as the sum of a convex combination of extreme points of P and a non‐negative linear combination of extreme rays of P. Grötschel, Lovász, and Schrijver ...
    • Allocation Strategies in Hub Networks 

      Yaman, H. (Elsevier, 2011-06-11)
      In this paper, we study allocation strategies and their effects on total routing costs in hub networks. Given a set of nodes with pairwise traffic demands, the p-hub median problem is the problem of choosing p nodes as hub ...
    • Ambulance location for maximum survival 

      Erkut, E.; Ingolfsson, A.; Erdoğan, G. (John Wiley & Sons, 2008)
      This article proposes new location models for emergency medical service stations. The models are generated by incorporating a survival function into existing covering models. A survival function is a monotonically decreasing ...
    • Analysis and applications of replenishment problems under stepwise transportation costs and generalized wholesale prices 

      Konur, D.; Toptal, A. (2012)
      In this study, we analyze the replenishment decision of a buyer with the objective of maximizing total expected profits. The buyer faces stepwise freight costs in inbound transportation and a hybrid wholesale price schedule ...
    • Analysis of a decentralized supply chain under partial cooperation 

      Güllü, R.; Van Houtum G. J.; Sargut F. Z.; Erkip, N. (2005)
      In this article, we analyze a decentralized supply chain consisting of a supplier and two independent retailers. In each order cycle, retailers place their orders at the supplier to minimize inventory-related expected costs ...
    • Analysis of assembly systems for interdeparture time variability and throughput 

      Sabuncuoğlu, İ.; Erel, E.; Kok, A. G. (Taylor & Francis, 2002)
      This paper studies the effect of the number of component stations (parallelism), work transfer, processing time distributions, buffers and buffer allocation schemes on throughput and interdeparture time variability of ...
    • An analysis of cyclic scheduling problems in robot centered cells 

      Yıldız, Serdar; Karasan, Oya Ekin; Aktürk, M. Selim (Elsevier, 2012)
      The focus of this study is a robot centered cell consisting of m computer numerical control (CNC) machines producing identical parts. Two pure cycles are singled out and further investigated as prominent cycles in minimizing ...
    • An analysis of heuristics in a dynamic job shop with weighted tardiness objectives 

      Kutanoglu, E.; Sabuncuoğlu, İ. (Taylor & Francis, 1999)
      Meeting due dates as a reflection of customer satisfaction is one of the scheduling criteria that is frequently encountered in today's manufacturing environments. The natural quantification of this qualitative goal involves ...
    • An analysis of manufacturer benefits under vendor-managed systems 

      Savaşaneril, S.; Erkip, N. (Taylor & Francis, 2010)
      Vendor-Managed Inventory (VMI) has attracted a lot of attention due to its benefits such as fewer stock-outs, higher sales, and lower inventory levels at the retailers. Vendor-Managed Availability (VMA) is an improvement ...