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Mario Guajardo Mikael Rönnqvist 《International Transactions in Operational Research》2016,23(3):371-392
Collaboration in transportation between two or more agents is becoming an important approach to find efficient solutions or plans. Efficiency can be measured in, for example, lower cost or more flexibility. An important aspect of the collaboration is to decide on how to share the benefits—for example, cost, profit, or resources. There are many sharing mechanisms or cost allocations proposed in the literature. Some are based on simple proportional rules and others are based on theoretical concepts found in game theory. We provide a survey on cost allocation methods found in the literature on collaborative transportation, including problems on planning, vehicle routing, traveling salesman, distribution, and inventory. A total of 55 scientific articles compose the main part of the survey, most of them published between 2010 and 2015. We identify more than 40 cost allocation methods used in this stream of literature. We describe the theoretical basis for the main methods as well as the cases where they are used. We also report savings from the collaborations when they are based on industrial data. Some directions for future research are discussed. 相似文献
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Mario Guajardo Martin Kylinger Mikael Rnnqvist 《International Transactions in Operational Research》2013,20(6):889-916
In divergent supply chains, such as in the oil industry, processing raw materials results in an outflow of multiple products. Final products are stored at international depots, from where they are ready to be shipped to the markets. Even if one company controls the entire chain, when production and sales organizations are decoupled, a relevant problem is to determine the internal prices of products at depots for achieving coordination. We propose an optimization model involving pricing and production decisions, and several constraints commonly used in divergent chains. In our approach, the producer incorporates the sellers’ behavior by expressing demand as a function of the internal price. As a result, our model serves as a coordination mechanism in trying to get an overall coordinated integrated solution in a decoupled reality. Numerical examples in single and multiple periods problems show the advantages of our approach over cost‐based methods. 相似文献
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In this paper, an analysis of the performance, failure and reliability, as well as a spare parts analysis have been conducted for a wind farm, which has 15 wind turbine generators (WTGs), each of 225 kW capacity. This wind farm is located at Muppandal, Tamil Nadu, South India. The average value of performance parameters such as technical availability, real availability and capacity factor for the wind farm were 94%, 82.88% and 24.9% respectively during the years 2000–2004. This paper also deals with Pareto analysis to find out the reduction in problems, when one problem is tackled partly and completely. The Weibull technique was also used for the reliability analysis. The reliability factor in the initial period after one year seems to be good as the wind farm has a lower failure rate of 0.000019. As a supplemental activity, spare parts optimization was also carried out for a few vital components of this wind farm and the results are presented. The failure and its financial implications are also analyzed in this paper. 相似文献
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Spectral fluorometric characterization of phytoplankton community composition using the Algae Online Analyser 总被引:1,自引:0,他引:1
Tammi L. Richardson Evelyn Lawrenz Rodney C. Guajardo Hans W. Paerl 《Water research》2010,44(8):2461-22658
The utility of a multiple-fixed-wavelength spectral fluorometer, the Algae Online Analyser (AOA), as a means of quantifying phytoplankton biomass and community composition was tested using natural communities from two southeastern United States estuaries, North Inlet, South Carolina, and the Neuse River Estuary, North Carolina. Estimates of biomass (as chlorophyll a) were correlated with HPLC values and variations (usually over-estimates) were consistent with effects of light intensity and nutrient availability on fluorescence quenching. AOA estimates of taxonomic structure were consistent with those from HPLC-derived marker pigments by ChemTax, with both methods indicating domination by chromophytes and green algae in North Inlet and chromophytes and cyanobacteria in the Neuse. We recommend frequent calibration by discrete sample collection, and calibration with species representative of the region of interest. Overall, the AOA appears to be a useful tool for monitoring of phytoplankton community composition, especially as an early warning system for the detection of harmful algal blooms. 相似文献
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Fernando Alarcón Guillermo Durán Mario Guajardo 《International Transactions in Operational Research》2014,21(3):415-438
This article uses integer linear programming to address the referee assignment problem in the First Division of the Chilean professional football league. The proposed approach considers balance in the number of matches each referee must officiate, the frequency of each referee being assigned to a given team, the distance each referee must travel over the course of a season, and the appropriate pairings of referee experience or skill category with the importance of the matches. Two methodologies are studied, one traditional and the other a pattern‐based formulation inspired by the home‐away patterns for scheduling season match calendars. Both methodologies are tested in real‐world and experimental instances, reporting results that improve significantly on the manual assignments. The pattern‐based formulation attains major reductions in execution times, solving real instances to optimality in just a few seconds, while the traditional one takes anywhere from several minutes to more than an hour. 相似文献
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Zamora J Velásquez A Troncoso L Barra P Guajardo K Castillo-Duran C 《Archivos latinoamericanos de nutrición》2011,61(3):242-246
The attention-deficit/hyperactivity disorder (ADHD) is a neurological/behavioral disorder which begins in childhood. Zinc has a potential role as an adjuvant therapy for ADHD. The objective was to evaluate the effect ofZn supplementation on behavior, as a complementary therapy to metylphenidate, in pediatrics patients with ADHD. In a controlled, double blind design, 40 patients with clinical criteria ofADHD (DSM-IV) and psychometric evaluation (WISC-R), were selected (31 boys and 9 girls, 7-14 years of age). They were randomized to receive methylphenidate 0.3 mg/kg/d + placebo (sucrose) (group placebo, GPL) or methylphenidate 0.3 mg/kg/d + zinc (sulfate) 10 mg/d (group Zn, GZN) for 6 weeks. A blood sample was drawn at time 0 and 6 weeks, for plasma Zn analysis. The teacher and parent ADHD rating scale (Conners' global index, CGI) was applied at both times. Among the results, plasma Zn was normal at time 0, decreasing especially in the GPL after 6 weeks (GPL: 95.9 +/- 21.5 to 77.9 +/- 15.5; GZN: 90.3 +/- 9.1 to 85.0 +/- 12.0 microg/dL; NS). The CGI by teachers showed a non-significant improvement with Zn: GPL: 18 (9-28) to 16 points (2-26); GZN: 19 (6-24) to 11 points (3-23) (p = 0.07); no significant difference in the CGI by parents by groups was found: GPL: 19 (7-25) to 13 (3-22); GZN: 19(7-25) to 11(2-19). We conclude that a decrease in plasma Zn levels in both groups was found, greater in the placebo group. An apparent improvement in ADHD signs in children was observed with the Zn supplementation, according to the Conners global index by teachers. 相似文献
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Guajardo Humberto S.; Bagladi Verónica L.; Kushner Diana L. 《Canadian Metallurgical Quarterly》2004,14(3):290
In most countries, addictive disorders have increased considerably in the recent years, becoming a main problem of public health for governments. One approach toward the rehabilitation of people with addictive disorders is in Chile's Therapeutic Communities. In such communities, recovering addicts actively collaborate in the rehabilitation of people in treatment. The characteristics of the rehabilitation process are presented from the perspective of the supraparadigmatic integrative model proposed by R. Opazo (1997). The application of an integrative clinical evaluation record (Ficha de Evaluacion Clinica Integral) helps one to understand, through the different subsystems of the model, the presenting problems of persons entering rehabilitation, the etiological role of each subsystem, and the modification that takes place during treatment. Biological predisposing factors such as extraversion and neurological immaturity are resistant to treatment modification; however, alterations acquired during the addictive process, in all the subsystems of the model, are modifiable after 9 months of integrative psychotherapy. On the basis of the authors' observations and on the supraparadigmatic integrative model, an etiological approach of addictive disorders is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献