35 research outputs found

    Cooperation Between Multiple Newsvendors with Warehouses

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    Analysis of an assembler-distributor network under revenue sharing and wholesale price contracts.

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    Tactical inventory planning at Alcatel-Lucent's repair and exchange services

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    Due to copyright restrictions, the access to the full text of this article is only available via subscription.Alcatel-Lucent, a major telecommunications equipment manufacturer, provides equipment, solutions, and services to customers worldwide. Post-sales support services are a growing business segment for the company, and require significant investment in spare parts. The inventory investment constitutes a considerable portion of the total cost of providing post-sales support services for new customer contracts; it is also an important element in estimating new contract offerings and evaluating and redesigning business processes that affect inventories. Because of Alcatel-Lucent’s two-echelon supply chain structure, inventory sizing for post-sales support services is a complicated task that spreadsheet applications cannot handle adequately. Thus, the company’s repair and exchange services (RES) group needed a fast, user-friendly, and generic software solution with advanced analytic capabilities to support its business tendering and evaluation processes. To meet this requirement, we developed the tactical inventory planning tool, which uses stochastic modeling and optimization algorithms, for this purpose. Although the tool’s primary function is to support the RES business tendering process, it has also been useful in other business analysis because of its generic nature.Industrial Development Agenc

    Controlled fertilizer release via tunable poly(vinyl alcohol)/ammonium sulfate-coated nonwoven materials

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    In this study, nonwoven fabrics were coated with two different ammonium sulfate fertilizer loadings (27.75% and 55.50%) by using two different poly(vinyl alcohol) types (high and low molecular weight). The poly(vinyl alcohol) coating amounts were adjusted to 60 and 120g/m(2). In order to study the effect of poly(vinyl alcohol) crosslinking on fertilizer release, a glutaraldehyde (GA) crosslinking agent was used in two different ratios (GA/PVOH ratio: 0.01 or 1). A concentration of 0.01GA was insufficient for PVOH crosslinking, and water absorption capacity was reduced with increasing poly(vinyl alcohol) and glutaraldehyde loading amount. Fertilizer release was affected mostly by molecular weight and loading amounts of poly(vinyl alcohol) and fertilizer. It was possible to achieve controlled fertilizer release when the nonwoven fabric was coated at 120g/m(2) with high molecular weight poly(vinyl alcohol) containing 55.50% ammonium sulfate fertilizer in the absence of glutaraldehyde

    Identifying the function of dimethylpyrazole phosphate as nitrification inhibitor in lettuce growth trials by using an agrotextile material with controlled fertilizer release property

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    In this study, a new agrotextile structure containing ammonium and nitrate fertilizers which is called controlled release fertilizer (CRF) was designed. The prepared structure was used in lettuce growth trials both in the absence and presence of dimethylpyrazole phosphate (DMPP) inhibitor. In order to better monitor nitrogen balance in the soil and total nitrogen amounts in the whole system including soil, plant, and agrotextile and thus revealing the efficacy of DMPP usage depending on fertilizer application type ((traditional (TF) or agrotextile (CRF)) and irrigation regime (100% and 50%), plants were harvested at three growth stages. Generally, independent of fertilizer application type, the effect of DMPP usage was more pronounced at 100% irrigation regime. Presence of DMPP and 100% irrigation in traditional fertilizer (TF) application increased soil ammonium nitrogen (NH4+-N) by 12.5% and 11.1% and decreased soil nitrate nitrogen (NO3--N) by 3.8% and 8.9% at 1st and 2nd harvest stages, respectively. DMPP usage in agrotextile (CRF) application with 100% irrigation improved NH4+-N by 353% and reduced NO3--N by 14.9% in the soil, when especially the 2nd harvest stage was considered. According to soil N results, it can be said that the DMPP usage increased the soil inorganic N content in both TF and CRF applications. But, plant N uptake results showed that the usage of DMPP either didn't change or worsen the nitrogen use efficiency in the TF and CRF applications, respectively
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