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The input-output model of economics uses a matrix representation of a nation’s (or a region’s) economy to predict the effect of changes in one industry on others and by consumers, government, and foreign suppliers on the economy (Miller & Blair, 1985). Because the economic constantly evolves, the input-output model needs to be updated at least annually to reflect the new circumstance. Unfortunately, in most countries such as Australia, the input-output model is only constructed every 3-4 years, because the large amount of monetary and human cost is involved to complete a survey (ABS, 2007a). The Centre for Integrated Sustainability Analysis (ISA), University of Sydney, is developing an integrated intelligent system to estimate and update the input-output model at different level on a regular basis.
The input-output model consists of a time series of matrices (Table 1) representing the industry structure of a given year. At Table 1, each entry represents the commodity flow between the industry sections of different regions. For example, the entry represents the commodity flow from the sheep industry at Victoria (VIC), a state of Australia, to the retail industry in China. In this example, the goods worth of 0.23 million dollar are sold. Often is missing as it is very detailed information and hard to be surveyed. However government agents published aggregated information more frequently, such as V and U which represent the total export of a given industry in Australia (ABS, 2007b). The aggregated information is available for a rather long period, for example agriculture information from 1861 to 2007 in the database (ABS, 2007b). It is worth clarifying that the aggregated information is not limited by the sums of rows or columns as the V and U. The main purpose of this distribute intelligent system is to utilize those available aggregated information and the economic models from previous years to populate and update current or future s to build a series of this economic models for current year or coming years.
Table 1. An example of the input-output table defined by the 3-level tree and the 2-level tree
| China (1) | U |
Shoe (1) | Retail (2) |
Australia (1) | NSW (1) | Sheep (1) | | | |
Oil (2) | | | |
VIC (2) | Sheep (1) | | | |
Oil (2) | | | |
V | | | |