Accuracy and precision assesment of stochastic simulation tools for springback variation

The sheet forming industry is plagued by inherent variations in its many input variables, making quality control and improvements a major hurdle. This is particularly poignant for Advanced High Strength Steels (AHSS), which exhibit a large degree of property variability. Current FE-based simulation packages are successful at predicting the manufacturability of a particular sheet metal components, however, due to their numerical deterministic nature are inherently unable to predict the performance of a real-life production process. Though they are now beginning to incorporate the stochastic nature of production in their codes. This work investigates the accuracy and precision of a current stochastic simulation package, AutoForm Sigma v4.1, by developing an experimental data set where all main sources of variation are captured through precise measurements and standard tensile tests. Using a Dual Phase 600Mpa grade steel a series of semi-cylindrical channels are formed at two Blank Holder Pressure levels where the response metric is the variation in springback determined by the flange angle. The process is replicated in AutoForm Sigma and an assessment of accuracy and precision of the predictions are performed. Results indicate a very good correspondence to the experimental trials, with mean springback response predicted to within 1 ° of the flange angle and the interquartile spread of results to within 0.22°.

Focus group discussions of literacy assessment and world wide web-based reading intervention

Focus groups provide a means for participants in research to take on a greater role in the evaluation of the research and planning of its various stages. The role and outcomes of focus groups conducted with participants in a World Wide Web Project in literacy assessment and intervention are reported. Thirteen individuals with severe communication impairments participated in one of three focus groups. The groups were held after an assesment of reading skills and a trial period of intervention as part of the Web Project. The aim of the focus groups was to obtain feedback from participants about their involvement in the project and to discuss strategies for the next stage of the intervention. The focus groups offered a forum for participants to talk about what they did and did not like about the assessment and trial intervention. The discussions provided information about issues of both a practical and emotional nature that might have otherwise been unavailable to the researchers. Brainstorming of strategies provided valuable input for the next stage of the project and involved both the researchers and participants in a form of participatory action research.

Local population preferences toward restoring ecosystem services of a wetland in Thailand

This study reports the findings of a choice experiment designed to explore local population preferences toward wetland ecosystem restoration of Bung Khong Long Wetland in Thailand. By addressing ecological, socioeconomic and cultural dimensions of ecosystem services, the findings provide policy-makers with a richer insight into the interconnections among ecological, socioeconomic and cultural systems in explaining the value of ecosystem services. Gaining an understanding of the trade-offs associated with different interests in ecosystem uses in this community has the capacity to promote wetland management and enhance land use planning. The choice experiment application entails selecting attributes and their levels and developing an experimental design to create the choice sets or hypothetical scenarios for welfare assessment via the questionnaire. The study is based on household level data collected from 780 randomly drawn respondents living around the lake and the data are analysed using the Random Parameter Logit Model with interactions. The findings indicate that the local population derives positive and significant values from the restoration of wetland ecosystem services, indicating caution is needed in the decision-making processes involving sensitive environments faced with competing uses. Socioeconomic and attitudinal characteristics of respondents are important factors influencing willingness to pay, implying community preferences are important in the effectiveness of environmental conservation efforts in this community. The cultural values associated with the wetland are significant suggesting that incorporating culture preferences may be a key factor in supporting wetland conservation.