A robustness approach to international sourcing

An important advantage of the use of international sourcing networks (i.e. selection of suppliers in various countries to support the demands of the firm's international factory network) is the resulting hedging power against real exchange rate changes in the international environment. Due to the uncertainty of future real exchange rate changes, the international manager wants to develop a sourcing network that is relatively insensitive (i.e. robust) to the potential changes of the macroeconomic parameters over a planning horizon. In our paper, we formally develop arobust approach to international sourcing. This approach develops the international supplier network in a way that adequately hedges the firm's performance against the worst contingency in terms of realizable real exchange rate shocks over a planning horizon. We present an algorithm to obtain theN best robust solutions (i.e. sourcing networks) to the international sourcing problem. Some computational results on the effectiveness of the approach are provided. We also demonstrate how the approach can be used to evaluate various sourcing strategies.     

On Generic Well-posedness of Restricted Chebyshev Center Problems in Banach Spaces

Let B （resp. K, BC,KC） denote the set of all nonempty bounded （resp. compact, bounded convex, compact convex） closed subsets of the Banach space X, endowed with the Hausdorff metric, and let G be a nonempty relatively weakly compact closed subset of X. Let B° stand for the set of all F ∈B such that the problem （F, G） is well-posed. We proved that, if X is strictly convex and Kadec, the set KC ∩ B° is a dense Gδ-subset of KC ／ G. Furthermore, if X is a uniformly convex Banach space, we will prove more, namely that the set B ／B° （resp. K ／ B°, BC ／B°, KC ／ B°） is a-porous in B （resp. K,BC, KC）. Moreover, we prove that for most （in the sense of the Baire category） closed bounded subsets G of X, the set K ／ B° is dense and uncountable in K.     

Resolvents of Set-Valued Monotone Vector Fields in Hadamard Manifolds

Firmly nonexpansive mappings are introduced in Hadamard manifolds, a particular class of Riemannian manifolds with nonpositive sectional curvature. The resolvent of a set-valued vector field is defined in this setting and by means of this concept, a strong relationship between monotone vector fields and firmly nonexpansive mappings is established. This fact is then used to prove that the resolvent of a maximal monotone vector field has full domain. The Yosida approximation of a set-valued vector field is also introduced, analyzing its properties from which the asymptotic behavior of the resolvent is studied. Regarding the singularities of a set-valued monotone vector field, existence results are proved under certain boundary condition. As a consequence, the existence of fixed points for continuous pseudo-contractive mappings is obtained.     

Intercalation and photophysical characterization of 1-pyrenemethylamine in zirconium phosphate layered materials

The ion exchange of the luminescent probe 1-pyrenemethylamine (PYMA) into zirconium phosphate (ZrP) layered materials has been accomplished. The matrices used were the hexahydrated 10.3 A phase of ZrP (10.3 A ZrP, where 10.3 A represents the interlayer distance) and butylammonium-exchanged ZrP (BAZrP) with an expanded 18.6 A interlayer distance. The XRPD patterns for the 10.3 A ZrP after PYMA exchange (PYMA-exchanged ZrP), at high PYMA concentrations, show an increase in the interlayer distance from 10.3 A in unexchanged 10.3 A ZrP to 23.5 A in PYMA-exchanged ZrP, indicating PYMA intercalation. The luminescence spectrum for the PYMA-exchanged ZrP exhibits an excimer band at 458 nm that is absent in the luminescence spectrum of PYMA in aqueous solution at low concentrations. The intensity of the excimer emission increased at low PYMA concentrations. These results are in contrast to experiments using the BAZrP matrix. The XRPD patterns for PYMA-exchanged BAZrP do not show changes in the interlayer distance, which suggests that PYMA is not being intercalated and is only surface bound. The luminescence spectrum for PYMA-exchanged BAZrP exhibits a lower emission intensity in its excimer band, at different PYMA concentrations, compared with the PYMA-exchanged ZrP excimer band. For PYMA-exchanged ZrP, we propose a process in which exchange at low PYMA concentrations occurs at external surface sites with clustering promoting excimer formation followed by exchange at high PYMA concentrations occurring at interior sites reducing excimer formation.