A service oriented architecture for engineering design

Decision making in engineering design can be effectively addressed by using genetic algorithms to solve multi-objective problems. These multi-objective genetic algorithms (MOGAs) are well suited to implementation in a Service Oriented Architecture. Often the evaluation process of the MOGA is compute-intensive due to the use of a complex computer model to represent the real-world system. The emerging paradigm of Grid Computing offers a potential solution to the compute-intensive nature of this objective function evaluation, by allowing access to large amounts of compute resources in a distributed manner. This paper presents a grid-enabled framework for multi-objective optimisation using genetic algorithms (MOGA-G) to aid decision making in engineering design

Multiobjective gas turbine engine controller design using genetic algorithms

This paper describes the use of multiobjective genetic algorithms (MOGAs) in the design of a multivariable control system for a gas turbine engine. The mechanisms employed to facilitate multiobjective search with the genetic algorithm are described with the aid of an example. It is shown that the MOGA confers a number of advantages over conventional multiobjective optimization methods by evolving a family of Pareto-optimal solutions rather than a single solution estimate. This allows the engineer to examine the trade-offs between the different design objectives and configurations during the course of an optimization. In addition, the paper demonstrates how the genetic algorithm can be used to search in both controller structure and parameter space thereby offering a potentially more general approach to optimization in controller design than traditional numerical methods. While the example in the paper deals with control system design, the approach described can be expected to be applicable to more general problems in the fields of computer aided design (CAD) and computer aided engineering (CAE

AN EVALUATION OF TEACHING EVALUATIONS: WHAT DO THE NUMBERS MEAN?

Student evaluation of teaching helps determine faculty merit ratings. A multinomial choice, ordered data model is used to identify factors having high statistical relevance with respect to value of the course and quality of instruction. Some results agree with findings from outside Agriculture, but there are interesting exceptions.Teaching/Communication/Extension/Profession,

Measuring Regional Productivity Differences in the Australian Wool Industry: A Metafrontier Approach

Using panel data, we estimate technology gaps for four distinct sheep-producing regions in Eastern Australia (Northern New South Wales, Central and South-Eastern New South Wales, South-Western New South Wales and South-West Victoria) that reflect spatial environmental and technological differences in wool production. A deterministic stochastic metafrontier production function model is estimated that envelops the stochastic frontiers of the four regions. This metafrontier approach enables us to estimate the environment-technology gap ratio that reflects these spatial differences in the environment and variations in production technologies in the wool enterprise for benchmarked farmers in each region. As a result, a more accurate estimation is possible of changes in total factor productivity on farms in the different regions. The major findings are that environment-technology gaps do exist between regions but they are relatively small. Greater variation is apparent within regions. Variation in technical efficiency seems to depend on the harshness of the production environment and whether consultancy advice is regularly received by the benchmarking group.Efficiency, Productivity, Metafrontier, Technology Gaps, Wool Production, Spatial, Livestock Production/Industries, Productivity Analysis, Research Methods/ Statistical Methods,

Evidence of Scope Economies in the Australian Wheat-Sheep Zone

Scope economies can be used in studies of farming systems to provide a measure of synergies between different farm enterprises and between activities within farm enterprises. In this paper, they are reported for farms in a benchmarking group in the Wheat-Sheep Zone in New South Wales, Australia, by estimating a stochastic input distance function and calculating an ‘economies of scope parameter’. Evidence is presented of scope economies between sheep and beef enterprises, sheep and crop enterprises, and beef and crop enterprises.Australia, crops, livestock, scope economies,

Slippage Effects of the Conservation Reserve Program: New Evidence from Satellite Imagery

The Conservation Reserve Program (CRP) is the largest land retirement program ever operated in the US. Since its inception in 1985, many researchers have studied the impacts of this program; however, only a few have analyzed how the CRP affects surrounding non–enrolled parcels. In this research I examine how the CRP may affect the conversion of non–cropped land to agriculture, a phenomenon referred to as “slippage” in the literature, and specifically addressed by Wu (2000) and Roberts and Bucholtz (2005). Building on these earlier studies, I empirically model slippage using data derived from satellite imagery that provides information on land cover changes between 1992 and 2001. The study area consists of 1,053 counties located in the Northern Plains, Corn Belt and Lake States regions. Results support the existence of slippage effects from the CRP, but they are more conservative than the ones found by Wu (2000). The evidence of slippage provided here is important information for planners, given that whether and how the CRP affects land use decisions in surrounding areas is key information for implementing conservation efforts more efficiently.CRP, Land use change, Satellite imagery, Slippage effect, Agricultural and Food Policy, Land Economics/Use, Q15, Q24,

THE ROLE OF SOIL TEST INFORMATION IN REDUCING GROUNDWATER POLLUTION

Will nitrogen soil testing improve groundwater quality enough to decrease the demand for direct regulation? This question is addressed using a dynamic simulation model of irrigated agriculture in eastern Oregon. Results indicate that soil testing reduces applied nitrogen, increases farm profits and improves groundwater quality, but not enough to avoid regulation.Environmental Economics and Policy,

Evidence of Scope Economies in Australian Agriculture

Scope economies can be used in studies of farming systems to provide a measure of synergies between different farm enterprises and between activities within farm enterprises. In this paper, they are reported for farms in three benchmarking groups in Australia by estimating stochastic input distance functions and calculating an 'economies of scope parameter'. Evidence of significant scope economies between sheep and crop enterprises, and between beef and crop enterprises, is presented and discussed. Similar evidence is reported between wool and lamb activities and wool and mature sheep trading activities within the sheep enterprise.Australia, Crops, Livestock, Sheep, Scope Economics, Crop Production/Industries, Livestock Production/Industries, Research Methods/ Statistical Methods, Industrial Organization,

Computational steering of a multi-objective genetic algorithm using a PDA

The execution process of a genetic algorithm typically involves some trial-and-error. This is due to the difficulty in setting the initial parameters of the algorithm – especially when little is known about the problem domain. The problem is magnified when applied to multi-objective optimisation, as care is needed to ensure that the final population of candidate solutions is representative of the trade-off surface. We propose a computational steering system that allows the engineer to interact with the optimisation routine during execution. This interaction can be as simple as monitoring the values of some parameters during the execution process, or could involve altering those parameters to influence the quality of the solutions produce by the optimisation process