22 research outputs found

    On the bullwhip avoidance phase: the synchronized supply chain

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    The aim of this paper is to analyse the operational response of a Synchronised Supply Chain (SSC). To do so, first a new mathematical model of a SSC is presented. An exhaustive Latin Square design of experi- ments is adopted in order to perform a boundary variation analysis of the main three parameters of the periodic review smoothing (S,R) order-up-to policy: i.e., lead time, demand smoothing forecasting factor, and proportional controller of the replenishment rule. The model is then evaluated under a variety of performance measures based on internal process benefits and customer benefits. The main results of the analysis are: (I) SSC responds to violent changes in demand by resolving bullwhip effect and by creating stability in inventories under different parameter settings and (II) in a SSC, long production\u2013 distribution lead times could significantly affect customer service level. Both results have important consequences for the design and operation of supply chains

    A Simulation Model of a Tandem Coordinated Supply Chain

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    This paper presents a study of a coordinated production inventory-system. In the proposed model, any echelon considers its successors as part of its inventory system and generates the replenishment order on the basis of operational information of its partners. We show that the coordinated decision making allows elimination of information distortion along the chain. Furthermore, we show how the bottom-up transmission of inefficiencies, typical of traditional supply chains, is avoided

    A Simulation Model of a Tandem Coordinated Supply Chain

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    On the Significance of Demand and Inventory Smoothing Interventions in Supply Chain

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    The aim of this paper is to quantify the benefit of demand and inventory smoothing in contrasting the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so we model a traditional supply chain and we test five settings of order smoothing under two shocks in the market demand, and we measure the effect in term of internal process benefits. Results highlight how a higher level of smoothing can generally improve the operational performance of the supply chain

    On the significance of demand and inventory smoothing interventions in supply chain

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    The aim of this paper is to quantify the benefit of demand and inventory smoothing in contrasting the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so we model a traditional supply chain and we test five settings of order smoothing under two shocks in the market demand, and we measure the effect in term of internal process benefits. Results highlight how a higher level of smoothing can generally improve the operational performance of the supply chain

    Near-infrared reflectance imaging in retinal diseases affecting young patients

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    Near-infrared reflectance (NIR) is a noninvasive, contactless, and rapid in vivo imaging technique for visualizing subretinal alterations in the photoreceptor layer, retinal pigment epithelium, and choroid. The present report describes the application of this imaging method in retinal and choroidal pathologies affecting young patients where scarce cooperation, poor fixation, and intense glare sensation can result in a challenging clinical examination. A literature search of the MEDLINE database was performed using the terms "near-infrared reflectance"and "spectral-domain optical coherence tomography."Articles were selected if they described the diagnostic use of NIR in children or young adults. Of 700 publications, 42 manuscripts published between 2005 and 2020 were inherent to children or young adults and were considered in this narrative literature review. The first disease category is the phakomatoses where NIR is essential in visualizing choroidal alterations recognized as cardinal biomarkers in neurofibromatosis type 1, microvascular retinal alterations, and retinal astrocytic hamartomas. Another diagnostic application is the accurate visualization of crystals of various nature, including the glistening crystals that characterize Bietti crystalline dystrophy. Acute macular neuropathy and paracentral acute middle maculopathy represent a further disease category with young adulthood onset where NIR is not only diagnostic but also essential to monitor disease progression. A further interesting clinical application is to facilitate the detection of laser-induced maculopathy where funduscopic examination can be normal or subnormal. In conclusion, NIR imaging has a noninterchangeable role in diagnosing certain retinal diseases, especially in children and young adults where there is scarce collaboration and a lack of evident clinical findings. Moreover, this technique can reveal unique retinal and choroidal biomarkers highly specific to rare conditions

    A step backward: The 'Rough' facial nerve grading system

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    Objectives: Several modalities currently exist to rate the degree of facial function clinically but even though it has significant limitations, the most widely used scale is the House-Brackmann grading system (HBGS). A simplified scale is introduced here, the 'Rough' Grading System (RGS - Grade I: normal movement; Grade II: slight paralysis; Grade III: frank paralysis with eye closure; Grade IV: frank paralysis without eye closure; Grade V: almost complete paralysis with only slight movements; Grade VI: total paralysis). The aim of the present study was to verify the interrater reliability and the interscale validity of this simplified grading system. Study design: Scale validation study based on a prospective cohort. Methods: Fifty patients with facial palsy, consecutively referred to our department were filmed while performing some codified facial movements. Then two independent groups (one rating using the HBGS, the other rating using the RGS) assigned a grade after reviewing the videos. The time required for the rating was also noted. Results: The HBGS showed a mean value of interrater agreement of 0.46 while the RGS showed a mean value of 0.59. The concurrent validity between HBGS and RGS ranged from 0.86 to 0.90 (p < 0.001 for every comparison). There was no statistically significant difference between HBGS and RGS in the mean time taken for rating (p = 0.15). Conclusions: The RGS reached an adequate level of interrater reliability, higher than the HBGS. The correlation between the two scales is high and the times required for rating are similar. The present results may justify the use of the RGS in routine clinical practice. Level of evidence: N/A. © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights
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