589 research outputs found

    Managing customer relationships through price and service quality

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    This paper examines the ways in which a service provider's policies on pricing and service level affect the size of its customer base and profitability. The analysis begins with the development of a customer behavior model that uses customer satisfaction and depth of relationship as mediators of the impact of price and service level on profitability. Based on this model of customer behavior, the system is analyzed as a queuing network from which the properties of the aggregate population's behavior are derived. The analysis reveals the counterintuitive result that a policy that involves a decrease in prices or an increase in service level may lead to a smaller customer base. However, this policy may also lead to higher profits. The novelty of this result lies in the explanation of the phenomenon: that when the customer base decreases due to a change in prices or service quality, companies may experience gains in profit that result not from a decrease in costs associated with serving fewer customers but from an increase in revenues resulting from the indirect effects of the lower prices or higher level of service on customer behavior. The application of optimization techniques to the model developed in this paper yields optimality conditions through which managers can assess the long-term profitability of their pricing and service-level policies.Customer relationship management; operations/marketing interface; two-part tariffs; service operations management; service quality;

    Duality Based Characterizations of Efficient Facets

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    Most practical applications of multicriteria decision making can be formulated in terms of efficient points determined by preference cones with polyhedral closure. Using linear approximations and duality from mathematical programming, we characterize a family of supporting hyperplanes that define the efficient facets of a set of alternatives with respect to such preference cones. We show that a subset of these hyperplanes generate maximal efficient facets. These characterizations permit us to devise a new algorithm for generating all maximal efficient facets of multicriteria optimization problems with polyhedral structure.Supported in part by the National Science Foundation grant MCS77-24654. Supported in part by the Army Research Office (Durham) contract DAAG29-76-C-0064

    Coordination of Supply Chain Networks and the Emergence of Mini-maestros

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    Abstract Companies recognize international sourcing as a business practice useful to reduce product prices, deal with supply shortages and identify new competitive suppliers. Effective international sourcing implies the integration and coordination of materials, processes, information flows and multiple producers at each buying location. Many companies do not have the capabilities or the willingness to develop and manage such sourcing networks; therefore, other entities have assumed these responsibilities. These coordinators are in charge of the integration of many suppliers to develop full-package production, serve as liaisons between suppliers’ capabilities and market demands, and provide the technical and financial support to sustain the sourcing network. The review of the industrial clustering and global supply chain literature allowed the identification of such coordinators in Mexico. The emergence and profile of these coordinators is associated with corporate strategies of multinational firms, the efforts of industrial groups, and the governmental policies for the development of dynamic industrial regions. This paper analyzes the characteristics of four coordination models identified in the Mexican context, focusing on their contribution to the participation and upgrading of national suppliers. The profile of the coordinator firm, the type of relations that this firm sustains with producers and the support offered to suppliers is also discussed. A particular emphasis is given to the fourth model where a third party, a knowledge and service company, assumes the coordinator role. The interest on this model is due to its novelty, the flexibility of the sourcing network, and the potential impact on regional development that could result from the intervention of a neutral third party as coordinator of the activities of multiple local and specialized suppliers

    Chirp filtering in the fractional Fourier Domain

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    Cataloged from PDF version of article.In the Wigner domain of a one-dimensional function, a certain chirp term represents a rotated line delta function. On the other hand, a fractional Fourier transform (FRT) can be associated with a rotation of the Wigner-distribution function by an angle connected with the FRT order. Thus with the FRT tool a chirp and a delta function can be transformed one into the other. Taking the chirp as additive noise, the FRT is used for filtering the line delta function in the appropriate fractional Fourier domain. Experimental filtering results for a Gaussian input function, which is modulated by an additive chirp noise, are shown. Excellent agreement between experiments and computer simulations is achieved

    Inverse Optimization: An Application to the Capacitated Plant Location Problem

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    Inverse optimization refers to the fact that each time a Lagrangean derived from a given mathematical programming problem is solved, it produces an optimal solution to some problem with a different right hand side. This paper reports on the application of inverse optimization to the capacitated plant location problem including the study of implied mappings of dual variables into the space of demand vectors. A new parametric method based on inverse optimization and subgradient optimization is also presented.Research supported, in part, by the National Science Foundation under Grant No. MCS77-24654

    Fractional Fourier Transform- Simulations and experimental results

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    Cataloged from PDF version of article.Recently two optical interpretations of the fractional Fourier transform operator were introduced. We address implementation issues of the fractional-Fourier-transform operation. We show that the original bulk-optics configuration for performing the fractional-Fourier-transform operation 3J. Opt. Soc. Am. A 10, 2181 1199324 provides a scaled output using a fixed lens. For obtaining a non-scaled output, an asymmetrical setup is suggested and tested. For comparison, computer simulations were performed. A good agreement between computer simulations and experimental results was obtained

    Anamorphic Fractional Fourier Transforming--Optical Implementation and Applications

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    Cataloged from PDF version of article.An additional degree of freedom is introduced to fractional-Fourier-transform systems by use of anamorphic optics. A different fractional Fourier order along the orthogonal principal directions is performed. A laboratory experimental system shows preliminary results that demonstrate the proposed theory. Applications such as anamorphic fractional correlation and multiplexing in fractional domains are briefly suggested. (C) 1995 Optical Society of Americ

    A computational analysis of lower bounds for big bucket production planning problems

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    In this paper, we analyze a variety of approaches to obtain lower bounds for multi-level production planning problems with big bucket capacities, i.e., problems in which multiple items compete for the same resources. We give an extensive survey of both known and new methods, and also establish relationships between some of these methods that, to our knowledge, have not been presented before. As will be highlighted, understanding the substructures of difficult problems provide crucial insights on why these problems are hard to solve, and this is addressed by a thorough analysis in the paper. We conclude with computational results on a variety of widely used test sets, and a discussion of future research

    A Mixed-Integer Linear Programming Model for Transportation Planning in the Full Truck Load Strategy to Supply Products with Unbalanced Demand in the Just in Time Context: A Case Study

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    [EN] Growing awareness in cutting transport costs and minimizing the environmental impact means that companies are increasingly interested in using the full truck load strategy in their supply tasks. This strategy consists of filling trucks completely with one product type or a mixture of products from the same supplier. This paper aims to propose a mixed-integer linear programming model and procedure to fill trucks which considers limitations of stocks, stock levels and unbalanced demand and minimization of the total number of trucks used in the full truck load strategy. The results obtained from a case study are presented and are exported in a conventional spreadsheet available for a company in the automotive industry.Maheut ., JP.; García Sabater, JP. (2013). A Mixed-Integer Linear Programming Model for Transportation Planning in the Full Truck Load Strategy to Supply Products with Unbalanced Demand in the Just in Time Context: A Case Study. IFIP Advances in Information and Communication Technology. 397:576-583. doi:10.1007/978-3-642-40361-3_73S576583397Bitran, G.R., Haas, E.A., Hax, A.C.: Hierarchical production planning: a single stage system. Operations Research 29, 717–743 (1981)Sun, H., Ding, F.Y.: Extended data envelopment models and a practical tool to analyse product complexity related to product variety for an automobile assembly plant. International Journal of Logistics Systems and Management 6, 99–112 (2010)Boysen, N., Fliedner, M.: Cross dock scheduling: Classification, literature review and research agenda. Omega 38, 413–422 (2010)Garcia-Sabater, J.P., Maheut, J., Garcia-Sabater, J.J.: A two-stage sequential planning scheme for integrated operations planning and scheduling system using MILP: the case of an engine assembler. Flexible Services and Manufacturing Journal 24, 171–209 (2012)Ben-Khedher, N., Yano, C.A.: The Multi-Item Replenishment Problem with Transportation and Container Effects. Transportation Science 28, 37–54 (1994)Cousins, P.D.: Supply base rationalisation: myth or reality? European Journal of Purchasing Supply Management 5, 143–155 (1999)Kiesmüller, G.P.: A multi-item periodic replenishment policy with full truckloads. International Journal of Production Economics 118, 275–281 (2009)Goetschalckx, M.: Transportation Systems Supply Chain Engineering, vol. 161, pp. 127–154. Springer, US (2011)Liu, R., Jiang, Z., Fung, R.Y.K., Chen, F., Liu, X.: Two-phase heuristic algorithms for full truckloads multi-depot capacitated vehicle routing problem in carrier collaboration. Computers Operations Research 37, 950–959 (2010)Arunapuram, S., Mathur, K., Solow, D.: Vehicle Routing and Scheduling with Full Truckloads. Transportation Science 37, 170–182 (2003

    The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter

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    We analyse IRAS and COBE DIRBE data at wavelengths between 2.2 and 240 mu of the central 500pc of the Galaxy and derive the large-scale distribution of stars and interstellar matter in the Nuclear Bulge. Models of the Galactic Disk and Bulge are developed in order to correctly decompose the total surface brightness maps and to apply proper extinction corrections. The Nuclear Bulge appears as a distinct, massive disk-like complex of stars and molecular clouds which is, on a large scale, symmetric with respect to the Galactic Centre. It is distinguished from the Galactic Bulge by its flat disk-like morphology, very high density of stars and molecular gas, and ongoing star formation. The Nuclear Bulge consists of an R^-2 Nuclear Stellar Cluster at the centre, a large Nuclear Stellar Disk with radius 230+-20 pc and scale height 45+-5 pc, and a Nuclear Molecular Disk of same size. Its total stellar mass and luminosity are 1.4+-0.6 10^9 M_sun and 2.5+-1 10^9 L_sun, respectively. The total mass of interstellar hydrogen in the Nuclear Bulge is 2+-0.3 10^7 M_sun. Interstellar matter in the Nuclear Bulge is very clumpy with ~90% of the mass contained in dense and massive molecular clouds with a volume filling factor of only a few per cent. This extreme clumpiness enables the strong interstellar radiation field to penetrate the entire Nuclear Bulge and explains the relatively low average extinction towards the Galactic Centre. In addition, we find 4 10^7 M_sun of cold and dense material located outside the Nuclear Bulge, which gives rise to the observed asymmetry in the distribution of interstellar matter in the Central Molecular Zone.Comment: 28 pages, 22 figures, accepted for publication in A&
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