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: Using Engel curves to measure CPI bias for Indonesia

authors: Olivia, Susan

subjects: CPI bias

abstract: To measure real income growth over time a price index is needed to adjust for changes in the cost of living. The Consumer Price Index (CPI) is often used for this task but studies from several countries show the CPI is a biased measure of changes in the cost of living, leading to potentially wrong estimates of the rate of growth of real income. In this paper CPI bias for Indonesia is calculated by estimating food Engel curves for households with the same level of CPI-deflated incomes at four different points in time between 1993 and 2008. The results suggest CPI bias was initially negative during the Asian Crisis but has been positive since 2000. Over the entire period, CPI bias has averaged four percent annually, equivalent to almost one-third of the measured inflation rate.

text: Using Engel curves to measure CPI bias for Indonesia To measure real income growth over time a price index is needed to adjust for changes in the cost of living. The Consumer Price Index (CPI) is often used for this task but studies from several countries show the CPI is a biased measure of changes in the cost of living, leading to potentially wrong estimates of the rate of growth of real income. In this paper CPI bias for Indonesia is calculated by estimating food Engel curves for households with the same level of CPI-deflated incomes at four different points in time between 1993 and 2008. The results suggest CPI bias was initially negative during the Asian Crisis but has been positive since 2000. Over the entire period, CPI bias has averaged four percent annually, equivalent to almost one-third of the measured inflation rate.

year: 2012-06

title: Joseph Harris Smallman

authors: Hart, Philip

abstract: Born to a mining agent and trained as a mining surveyor, in 1864, less than a year after the birth of his first child, Smallman left England for New Zealand to establish a ‘Mining business’, promising that his family would join him once it was successful. But they were never asked to join him, and after 1870 he ceased to write to his wife. 
The ‘Mining business’ never eventuated, but in 1865 he prospected at Thames, unsuccessfully seeking alluvial gold. Although criticized for living off Maori and doing little prospecting, with his partner he investigated several areas of the Hauraki Peninsula, again unsuccessfully. When the Thames goldfield was opened, with his encouragement, two years later, he mined there for some years, proving himself to be a competent miner but not making his fortune. After working elsewhere, by the mid-1870s he was living with another man’s ‘half-caste’ wife on her land near Te Aroha, having five children with her. Happy to be described as a Pakeha Maori and closely associated with the local hapu, he supported them over land dealings and the development of the district. Despite spending most of his time farming, he remained interested in prospecting, and made some explorations in districts closed to Pakeha. After gold was found at Te Aroha, for a short time he worked with Maori partners in unprofitable claims.
Either before or after his second wife had a child by another man in 1886, he left New Zealand to return to his English family; and remarkably, despite his first wife knowing that his liaison had produced children, she accepted him back after his long absence, and they remained together for the rest of their lives.

text: Joseph Harris Smallman Born to a mining agent and trained as a mining surveyor, in 1864, less than a year after the birth of his first child, Smallman left England for New Zealand to establish a ‘Mining business’, promising that his family would join him once it was successful. But they were never asked to join him, and after 1870 he ceased to write to his wife. 
The ‘Mining business’ never eventuated, but in 1865 he prospected at Thames, unsuccessfully seeking alluvial gold. Although criticized for living off Maori and doing little prospecting, with his partner he investigated several areas of the Hauraki Peninsula, again unsuccessfully. When the Thames goldfield was opened, with his encouragement, two years later, he mined there for some years, proving himself to be a competent miner but not making his fortune. After working elsewhere, by the mid-1870s he was living with another man’s ‘half-caste’ wife on her land near Te Aroha, having five children with her. Happy to be described as a Pakeha Maori and closely associated with the local hapu, he supported them over land dealings and the development of the district. Despite spending most of his time farming, he remained interested in prospecting, and made some explorations in districts closed to Pakeha. After gold was found at Te Aroha, for a short time he worked with Maori partners in unprofitable claims.
Either before or after his second wife had a child by another man in 1886, he left New Zealand to return to his English family; and remarkably, despite his first wife knowing that his liaison had produced children, she accepted him back after his long absence, and they remained together for the rest of their lives.

year: 2016