title: A genetic algorithm for a bicriteria supplier selection problem

authors: Basnet, Chuda

subjects: supplier selection

abstract: In this paper, we discuss the problem of selecting suppliers for an organisation, where a number of suppliers have made price offers for supply of items, but have limited capacity. Selecting the cheapest combination of suppliers is a straightforward matter, but purchasers often have a dual goal of lowering the number of suppliers they deal with. This second goal makes this issue a bicriteria problem – minimisation of cost and minimisation of the number of suppliers. We present a mixed integer programming (MIP) model for this scenario. Quality and delivery performance are modelled as constraints. Smaller instances of this model may be solved using an MIP solver, but large instances will require a heuristic. We present a multi-population genetic algorithm for generating Pareto-optimal solutions of the problem. The performance of this algorithm is compared against MIP solutions and Monte Carlo solutions.

text: A genetic algorithm for a bicriteria supplier selection problem In this paper, we discuss the problem of selecting suppliers for an organisation, where a number of suppliers have made price offers for supply of items, but have limited capacity. Selecting the cheapest combination of suppliers is a straightforward matter, but purchasers often have a dual goal of lowering the number of suppliers they deal with. This second goal makes this issue a bicriteria problem – minimisation of cost and minimisation of the number of suppliers. We present a mixed integer programming (MIP) model for this scenario. Quality and delivery performance are modelled as constraints. Smaller instances of this model may be solved using an MIP solver, but large instances will require a heuristic. We present a multi-population genetic algorithm for generating Pareto-optimal solutions of the problem. The performance of this algorithm is compared against MIP solutions and Monte Carlo solutions.

year: 2009

title: Alkynyl and poly-ynyl derivatives of carbon-tricobalt clusters

authors: Antonova, Alla B.

subjects: carbon-tricobalt cluster

abstract: A series of alkynyl-tricobalt carbonyl clusters, Co₃(μ₃-CnR)(μ-dppm)(CO)₇ [R = But, Ph, C₆H₄I, C₆H₄C≡CPh, SiMe₃, Fc, Au(PPh₃)] containing three, five or seven carbons in the chain, have been prepared by elimination of phosphine–gold(I) halides in reactions between Co₃(μ₃-CBr)(μ-dppm)(CO)₇ and Au(C≡CR)(PPh₃) or between Co₃{μ₃-CC≡CAu(PR₃)} (μ-dppm)(CO)₇ (R = Ph, tol) and IC≡CR′ (R′ = SiMe₃, Fc). The use of poly-substituted arenes or ferrocenes has enabled preparation of the complexes 1,4-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂C₆H₃X-5 (X = H, Br), 1,3,5-{(OC)₇(μ-dppm)Co₃(μ₃-CC≡C)}₃C₆H₃ and 1,1′-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂Fc′ [Fc′ = Fe(η-C₅H₄-)₂]. The X-ray determined molecular structures of 12 of the complexes are reported.

text: Alkynyl and poly-ynyl derivatives of carbon-tricobalt clusters A series of alkynyl-tricobalt carbonyl clusters, Co₃(μ₃-CnR)(μ-dppm)(CO)₇ [R = But, Ph, C₆H₄I, C₆H₄C≡CPh, SiMe₃, Fc, Au(PPh₃)] containing three, five or seven carbons in the chain, have been prepared by elimination of phosphine–gold(I) halides in reactions between Co₃(μ₃-CBr)(μ-dppm)(CO)₇ and Au(C≡CR)(PPh₃) or between Co₃{μ₃-CC≡CAu(PR₃)} (μ-dppm)(CO)₇ (R = Ph, tol) and IC≡CR′ (R′ = SiMe₃, Fc). The use of poly-substituted arenes or ferrocenes has enabled preparation of the complexes 1,4-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂C₆H₃X-5 (X = H, Br), 1,3,5-{(OC)₇(μ-dppm)Co₃(μ₃-CC≡C)}₃C₆H₃ and 1,1′-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂Fc′ [Fc′ = Fe(η-C₅H₄-)₂]. The X-ray determined molecular structures of 12 of the complexes are reported.

year: 2006-04-01

title: Racism and intersections with health services

authors: Cormack, Donna

abstract: WERO webinar hosted by Māori and Indigenous Analysis Ltd & AATEA Solutions.

text: Racism and intersections with health services WERO webinar hosted by Māori and Indigenous Analysis Ltd & AATEA Solutions.

year: 2025-10-07