Implementing evaluation of the measurement process in an automotive manufacturer: a case study

Reducing process variability is presently an area of much interest in manufacturing organizations. Programmes such as Six Sigma robustly link the financial performance of the organization to the degree of variability present in the processes and products of the organization. Data, and hence measurement processes, play an important part in driving such programmes and in making key manufacturing decisions. In many organizations, however, little thought is given to the quality of the data generated by such measurement processes. By using potentially flawed data in making fundamental manufacturing decisions, the quality of the decision-making process is undermined and, potentially, significant costs are incurred. Research in this area is sparse and has concentrated on the technicalities of the methodologies available to assess measurement process capability. Little work has been done on how to operationalize such activities to give maximum benefit. From the perspective of one automotive company, this paper briefly reviews the approaches presently available to assess the quality of data and develops a practical approach, which is based on an existing technical methodology and incorporates simple continuous improvement tools within a framework which facilitates appropriate improvement actions for each process assessed. A case study demonstrates the framework and shows it to be sound, generalizable and highly supportive of continuous improvement goals

Differential Attention to Attributes in Utility-theoretic Choice Models

We show in a theoretical model that benefits of allocating additional attention to evaluating the marginal attribute with in choice set depend upon the expected utility loss from making a suboptimal choice as a result of ignoring that incremental attribute. Guided by this analysis, we then develop a very general and practical empirical method for measuring the individual's propensity to attend to attributes. As a proof of concept, we offer an empirical example of our method using a conjoint analysis of demand for programs to reduce health risks. Our results suggest that respondents differentially allocate attention across attributes, as a function of the mix of attribute levels in a choice set. This behavior can cause researchers who fail to model attention allocation to incorrectly estimate the marginal utilities derived from selected attributes. This illustrative example is a first attempt to implement an attention-corrected choice model with a sample of field data from a conjoint choice experiment.conjoint choice, bounded rationality, attention to attributes, choice set design

Asymmetric preference formation in willingness to pay estimates in discrete choice models

Individuals when faced with choices amongst a number of alternatives often adopt a variety of processing rules, ranging from simple linear to complex non-linear treatment of each attribute defining the offer of each alternative. In this paper we investigate the presence of asymmetry in preferences to test for reference effects and differential willingness to pay according to whether we are valuing gains or losses. The findings offer clear evidence of an asymmetrical response to increases and decreases in attributes when compared to the corresponding values for a reference alternative, where the degree of asymmetry varies across attributes and population segments

An Analysis of Motorists’ Route Choice Using Stated Preference Techniques

This paper presents some results of an analysis of motorists' route choice based on stated preference responses. This is done for both an inter-urban and urban route choice context. The nature of the study is exploratory; the analysis being based upon a pilot survey of some 79 motorists undertaken in March/April 1984. The quality and nature of the responses are assessed in terms of a 'rationality' test and also through a consideration of lexicographical forms of decision making. The formal quantitative analysis examines the ranked preferences of motorists by means of an ordered multinomial logit model. Detailed results are presented for various formulations of the representative utility function to assess the influence of various relevant variables upon mute choice and to identify the best explanation of motorists' stated route preferences in both route choice contexts. Values of time are derived for a variety of rodel specifications as part of this consideration of the usefullness of the ranking approach to an analysis of motorists route choice

An incremental approach to genetic algorithms based classification

Incremental learning has been widely addressed in the machine learning literature to cope with learning tasks where the learning environment is ever changing or training samples become available over time. However, most research work explores incremental learning with statistical algorithms or neural networks, rather than evolutionary algorithms. The work in this paper employs genetic algorithms (GAs) as basic learning algorithms for incremental learning within one or more classifier agents in a multi-agent environment. Four new approaches with different initialization schemes are proposed. They keep the old solutions and use an “integration” operation to integrate them with new elements to accommodate new attributes, while biased mutation and crossover operations are adopted to further evolve a reinforced solution. The simulation results on benchmark classification data sets show that the proposed approaches can deal with the arrival of new input attributes and integrate them with the original input space. It is also shown that the proposed approaches can be successfully used for incremental learning and improve classification rates as compared to the retraining GA. Possible applications for continuous incremental training and feature selection are also discussed

Consumers Valuations and Choice Processes of Food Safety Enhancement Attributes: An International Study of Beef Consumers

Food safety concerns have had dramatic impacts on food and livestock markets in recent years. Here we examine consumer preferences for various beef food safety assurances. In particular, we evaluate the extent to which such preferences are heterogeneous within and across country-of-residence defined groups and examine the distributional nature of these preferences with respect to marginal improvements in food safety. We collected data from over 4,000 U.S., Canada, Japan, and Mexican consumers. Using mixed logit models we find that Japanese and Mexican consumers have WTP preferences that are nonlinear in the level of food safety risk reduction. Conversely, U.S .and Canadian consumers appear to possess linear preferences. These results suggest that optimal food safety investment strategies hinge critically upon consumer perception of actual food safety improvements, the distributional relationship describing the targeted consumer segment's tradeoff function between WTP premiums and risk reduction levels, and the cost structure of these investments.consumer beef preference, food safety, investment decision, mixed logit, willingness-to-pay, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,

Selective Employment Subsidies: Can Okun’s Law Be Repealed?

[Excerpt] Concern that structural factors impede efficient labor market performance is evidenced in both statistical analyses of economic potential and policy proposals for selective employment subsidies. Estimates of the level and expected growth of full-employment GNP have recently been revised downward, as has the 3.2 unemployment multiplier implicit in Okun\u27s Law (see U.S. Council of Economic Advisers and George Perry). These indications of structural changes in labor markets reinforce statistics showing excessively high unemployment rates for youths and blacks, and labor force participation rates that are increasing for women and decreasing for men. The simultaneous concern with high inflation and high measured unemployment, in the context of major changes in labor force composition and increased variance in sectoral unemployment rates (see Perry), has brought forth numerous and sizable selective employment subsidy policies (SESP) in both the United States and Western Europe. The SESP, changes in potential GNP, and Okun\u27s Law are not unrelated phenomena. This paper explores that relationship. Section I presents a brief taxonomy of the primary SESPs which are currently being discussed in Western industrialized countries. Section II provides the economic rationale underlying these measures. Section III explores the relationship of SESP to the prospective growth of aggregate output, in the context of Okun\u27s Law. Evidence on the existence and magnitude of changes in employment decisions in response to the New Jobs Tax Credit (NJTC) is presented in Section IV

Incremental multiple objective genetic algorithms

This paper presents a new genetic algorithm approach to multi-objective optimization problemsIncremental Multiple Objective Genetic Algorithms (IMOGA). Different from conventional MOGA methods, it takes each objective into consideration incrementally. The whole evolution is divided into as many phases as the number of objectives, and one more objective is considered in each phase. Each phase is composed of two stages: first, an independent population is evolved to optimize one specific objective; second, the better-performing individuals from the evolved single-objective population and the multi-objective population evolved in the last phase are joined together by the operation of integration. The resulting population then becomes an initial multi-objective population, to which a multi-objective evolution based on the incremented objective set is applied. The experiment results show that, in most problems, the performance of IMOGA is better than that of three other MOGAs, NSGA-II, SPEA and PAES. IMOGA can find more solutions during the same time span, and the quality of solutions is better

The Effects of a Provision Rule in Choice Modelling

This research report investigates the effects of including a provision rule in choice modelling non-market valuation studies. Split samples with and without a provision rule were used to test for differences in household willingness-to-pay for improvements in environmental quality in the Hawkesbury-Nepean catchment. Local/rural and distant/urban sub-samples of residents were selected. The results of the study show that the inclusion of a provision rule had an effect on preferences in the distant/urban communities; however, the impact of a provision rule in the local/rural community sub-samples was negligible.Choice modelling, incentive comparability, provision rule, non-market valuation, environment, Environmental Economics and Policy, Research Methods/ Statistical Methods,