127 research outputs found

    An analysis of order review

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    Ankara : Department of Industrial Engineering and the Institute of Engineering and Sciences of Bilkent Univ., 1995.Thesis (Master's) -- Bilkent University, 1995.Includes bibliographical references.Order Review/Release (ORR) activities have mostly been ignored in past job shop research. In the majority of these studies, arriving jobs are immediately released to the shop floor without considering any information about the job and the system status. In practice, however, jobs arriving at the shop are first collected in a pool and then released periodically according to some release criterion. Although practitioners use ORR mechanisms to improve shop floor performance, researchers have found limited supports for the use of these input regulation policies. In this thesis, we reexamine the problem in a capacitated system. Specifically, we compare the performances of the ORR policies in a job shop with finite buffer capacities and material handling considerations. A new ORR mechanism is also proposed and compared with other methods.Karapınar, H YavuzM.S

    Septal perforators stemming from a very long left main coronary artery

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    We report a case of a very long left main coronary artery, 58mm,  with septal perforators before bifurcation. The coronary arteries were seen clear of plaques. To the best of our knowledge this case is a very rare case because of the existance of the first and the second septal perforator arteries originating from a very long left main coronary artery

    Some Inevitable Remarks on “Tripled Fixed Point Theorems for Mixed Monotone Kannan Type Contractive Mappings”

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    We advise that the proof of Theorem 12 given by Borcut et al. (2014) is not correct, and it cannot be corrected using the same technique. Furthermore, we present some similar results as an approximation to the opened question if that statement is valid

    On some fixed point theorems under (α,ψ,ϕ) -contractivity conditions in metric spaces endowed with transitive binary relations

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    After the appearance of Nieto and Rodríguez-López’s theorem, the branch of fixed point theory devoted to the setting of partially ordered metric spaces have attracted much attention in the last years, especially when coupled, tripled, quadrupled and, in general, multidimensional fixed points are studied. Almost all papers in this direction have been forced to present two results assuming two different hypotheses: the involved mapping should be continuous or the metric framework should be regular. Both conditions seem to be different in nature because one of them refers to the mapping and the other one is assumed on the ambient space. In this paper, we unify such different conditions in a unique one. By introducing the notion of continuity of a mapping from a metric space into itself depending on a function α, which is the case that covers the partially ordered setting, we extend some very recent theorems involving control functions that only must be lower/upper semi-continuous from the right. Finally, we use metric spaces endowed with transitive binary relations rather than partial orders.This article was funded by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah. N Shahzad acknowledges with thanks DSR for financial support. A-F Roldán-López-de-Hierro is grateful to the Department of Quantitative Methods for Economics and Business of the University of Granada. The same author has been partially supported by Junta de Andalucía by project FQM-268 of the Andalusian CICYE
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