FE analysis on the influence of width direction deformation on springback control in v-bending by sheet forging

There have some problems in the press engineering. One of the most representative phenomena is springback. Traditionally, a series of empirical methods were used to obtain target bending angle. However, such methods are relied on the ability and experience of engineer. Therefore, the control of springback is important. According to the viewpoint of plastic processing, it is considered that springback could be controlled by sheet forging method which was added after V-bending process used a punch with a single lump-punch. On the other hand, warp would occur in air bending process when the ratio of width to thickness is relatively small. So, it is considered that width direction deformation would affect springback control to some extent in case of warp is occurred. In this study, V-bending and continuous forging processes were conducted used FE analysis. From the analytical results, occurrence of warp was found. Next, model of these processes in consideration of warp was re-modified. Finally, it was found that the springback was controlled to some extent derived from width direction deformation

Veblen goods and neighbourhoods: endogenising consumption reference groups

One of the significant developments in the last four decades of economics is the growing empirical evidence that individual consumption preferences, as mea- sured by self-reported life satisfaction, are neither fixed nor self-centred but are instead overwhelmingly dominated by externalities, partly in the form of reference levels set by others and by one’s own experience. Welfare analysis recognising this fact is likely to indicate enormous revisions for macroeconomic policy and social objectives as well as for what is taught in economics at all levels. Yet the task of constructing general equilibrium models based on this microeconomic re- ality is still in its infancy. In this work I take the conventional stance that decision makers understand their own utility function. Therefore, they can choose the mi- lieu in which they immerse themselves with the sophisticated understanding that it will affect their own consumption reference levels and therefore the degree of satisfaction they derive from their private consumption. At the same time, their private consumption will help to set the reference level for others in their chosen group. I treat theoretically the problem of such endogenous formation of consump- tion reference groups in the context of a simultaneous choice of neighbourhoods and home consumption amongst a heterogenous population. For both discrete and continuous distributions of types, I find general equilibrium outcomes in which differentiation of neighbourhoods occurs endogenously and I compare the welfare implications of growth in such economies.reference income; veblen goods; consumption reference groups; club goods

Integrated Likelihood Inference in Small Sample Meta-analysis for Continuous Outcomes

This paper proposes the use of the integrated likelihood for inference on the mean effect in small-sample meta-analysis for continuous outcomes. The method eliminates the nuisance parameters given by variance components through integration with respect to a suitable weight function, with no need to estimate them. The integrated likelihood approach takes into proper account the estimation uncertainty of within-study variances, thus providing confidence intervals with empirical coverage closer to nominal levels than standard likelihood methods. The improve- ment is remarkable when either (i) the number of studies is small to moderate or (ii) the small sample size of the studies does not allow to consider the within-study variances as known, as common in applications. Moreover, the use of the integrated likelihood avoids numerical pitfalls related to the estimation of variance components which can affect alternative likelihood approaches. The proposed methodology is illustrated via simulation and applied to a meta-analysis study in nutritional science

Players Market Value at Risk: A Model and Some Evidence for the German Bundesliga

The market value of players forms a major asset of any modern professional football club. As with any asset, the expected benefits from having the right to use a player within a team, are also offset by risks that must be managed adequately by the club. To this end we, describe a simple risk-management tool that managers of football clubs can use to model and monitor a player’s market value at risk. Our model consists of three elements. First, we use a quantile-regression approach to study how performance parameters of football players affect their market values. To this end, we study data for 327 players of the German Bundesliga for the season 2015/2016. Our estimation results show that the time played significantly affects the lower part of the conditional distribution of players market value, while the number of goals and passes (assists) affect the upper (middle) part of the conditional distribution. Second, we fit a flexible continuous probability density function to the estimated quantiles of the conditional distribution of players market value. Third, we analyze how performance parameters affect the market value at risk and the expected shortfall of market value. We use an out-of-sample analysis to validate our empirical model

Maintenance of Automated Test Suites in Industry: An Empirical study on Visual GUI Testing

Context: Verification and validation (V&V) activities make up 20 to 50 percent of the total development costs of a software system in practice. Test automation is proposed to lower these V&V costs but available research only provides limited empirical data from industrial practice about the maintenance costs of automated tests and what factors affect these costs. In particular, these costs and factors are unknown for automated GUI-based testing. Objective: This paper addresses this lack of knowledge through analysis of the costs and factors associated with the maintenance of automated GUI-based tests in industrial practice. Method: An empirical study at two companies, Siemens and Saab, is reported where interviews about, and empirical work with, Visual GUI Testing is performed to acquire data about the technique's maintenance costs and feasibility. Results: 13 factors are observed that affect maintenance, e.g. tester knowledge/experience and test case complexity. Further, statistical analysis shows that developing new test scripts is costlier than maintenance but also that frequent maintenance is less costly than infrequent, big bang maintenance. In addition a cost model, based on previous work, is presented that estimates the time to positive return on investment (ROI) of test automation compared to manual testing. Conclusions: It is concluded that test automation can lower overall software development costs of a project whilst also having positive effects on software quality. However, maintenance costs can still be considerable and the less time a company currently spends on manual testing, the more time is required before positive, economic, ROI is reached after automation

Financial health, exports, and firm survival: evidence from UK and French firms

We use firm-level data for the UK and France to assess the role of exporting in the link between financial health and firm survival. We examine whether firms at different stages of export activity (starters, exiters, continuers, switchers) react differently to changes in financial variables. In general, export starters and exiters experience much stronger adverse effects of financial constraints for their survival prospects. By contrast, the exit probability of continuous exporters and export switchers is less negatively affected by financial characteristics. These relationships between exporting, finance and survival are broadly similar in the UK and French samples

Testing Measurement Invariance with Ordinal Missing Data: A Comparison of Estimators and Missing Data Techniques

Ordinal missing data are common in measurement equivalence/invariance (ME/I) testing studies. However, there is a lack of guidance on the appropriate method to deal with ordinal missing data in ME/I testing. Five methods may be used to deal with ordinal missing data in ME/I testing, including the continuous full information maximum likelihood estimation method (FIML), continuous robust FIML (rFIML), FIML with probit links (pFIML), FIML with logit links (lFIML), and mean and variance adjusted weight least squared estimation method combined with pairwise deletion (WLSMV_PD). The current study evaluates the relative performance of these methods in producing valid chi-square difference tests (Δχ2) and accurate parameter estimates. The result suggests that all methods except for WLSMV_PD can reasonably control the type I error rates of (Δχ2) tests and maintain sufficient power to detect noninvariance in most conditions. Only pFIML and lFIML yield accurate factor loading estimates and standard errors across all the conditions. Recommendations are provided to researchers based on the results