陶瓷零件快速成型机辅料台的改进

基于层合速凝技术的陶瓷零件快速成型机,在陶瓷零件的层分加工过程中,铺料台的变形和平稳性,影响着零件 的成型精度和表面质量,针对快速成型机的铺料台,利用Workbenc:h的静力学分析,得到运动过程中铺料台的变形和应 力,以此来分析判断铺料台升降装置结构设计的合理性,及对陶瓷零件成型工艺造成的影响。通过将铺料台改进设计为 加强筋结构,通过分析可知铺料台的变形和应力明显减小,提高了陶瓷零件的成型精度和表面质量,满足了成型工艺的 要求。     

基于PLC的自动封塑灌装机控制系统设计

为提高系统运行效率,设计自动封塑灌装机控制系统。运用PLC技术和PID调节技术,控制加热棒的温度,同时 控制包装薄膜的送给长度,使得该系统运行效率有显著提高;采用HMI来设计系统的操作控制、报警显示、延时设定、温 度设定及产量显示界面,同时触摸屏与PLC进行实时通信,以满足用户对功能的需求;最终通过合理选取系统硬件,实 现了封塑过程中加热棒温度的实时、可靠控制。     

工业缝纫机气浮针杆的柔性联接装置

由于滑槽座导轨副的配合间隙等原因的存在,使得通过刚性连接柱传给工业缝纫机针杆的作用力造成其运动方 向偏移。设计了一种工业缝纫机气浮针杆的柔性联接装置,采用柔性铰链弹性变形产生微小角位移来非平行输出微位 移,用以减弱滑决受到刚性干扰传递给针杆而造成的运动影响,运用ANSYS对其变形及强度进行了校核与分析。结果 表明：ANSYS分析结果与理论设计计算对比验证了设计结构与强度的合理性;该柔性联接装置结构简单,定位精度高, 可以有效地解决刚性传递的干扰,实现精密微位移定位,为今后精密微位移机构的研究提供了很好的研究方法和指导。     

Improving the Milk Supply Chain in Developing Countries: Analysis,Insights, and Recommendations

Quality issues in milk—arising primarily from deliberate adulteration by producers—have been reported in several developing countries. In the milk supply chain, a station buys raw milk from a number of producers, mixes the milk and sells it to a firm (that then sells the processed milk to end consumers). We study a non‐cooperative game between a station and a population of producers. Apart from penalties on proven low‐quality producers, two types of incentives are analyzed: confessor rewards for low‐quality producers who confess and quality rewards for producers of high‐quality milk. Contrary to our expectations, whereas (small) confessor rewards can help increase both the quality of milk and the station's profit, quality rewards can be detrimental. We examine two structures based on the ordering of individual and mixed testing of milk: pre‐mixed individual testing (first test a fraction of producers individually and then [possibly] perform a mixed test on the remaining producers) and post‐mixed individual testing (first test the mixed milk from all producers and then test a fraction of producers individually). Whereas pre‐mixed individual testing can be socially harmful, a combination of post‐mixed individual testing and other incentives achieves a desirable outcome: all producers supply high‐quality milk with only one mixed test and no further testing by the station.     

Dynamic Financial Constraints: Distinguishing Mechanism Design From Exogenously Incomplete Regimes

We formulate and solve a range of dynamic models of constrained credit/insurance that allow for moral hazard and limited commitment. We compare them to full insurance and exogenously incomplete financial regimes (autarky, saving only, borrowing and lending in a single asset). We develop computational methods based on mechanism design, linear programming, and maximum likelihood to estimate, compare, and statistically test these alternative dynamic models with financial/information constraints. Our methods can use both cross‐sectional and panel data and allow for measurement error and unobserved heterogeneity. We estimate the models using data on Thai households running small businesses from two separate samples. We find that in the rural sample, the exogenously incomplete saving only and borrowing regimes provide the best fit using data on consumption, business assets, investment, and income. Family and other networks help consumption smoothing there, as in a moral hazard constrained regime. In contrast, in urban areas, we find mechanism design financial/information regimes that are decidedly less constrained, with the moral hazard model fitting best combined business and consumption data. We perform numerous robustness checks in both the Thai data and in Monte Carlo simulations and compare our maximum likelihood criterion with results from other metrics and data not used in the estimation. A prototypical counterfactual policy evaluation exercise using the estimation results is also featured.     

Gay Community Involvement: Its Interrelationships and Associations With Internet Use and HIV Risk Behaviors in Swedish Men Who Have Sex With Men

We measured aspects of “community involvement” chosen for men who have sex with men (MSM) in Sweden (gay places, media accessed, Internet, gay festivals, and social engagement, measured as proportion of gay friends) in two Swedish Internet-based samples from 2006 (n?=?3,202) and 2008 (n?=?4,715). Data showed low to moderate reliability with a moderate (0.57) alpha coefficient. While there is moderate internal consistency, as might be anticipated from measures of actual community involvement, they can be treated as scales. The Internet scale indicated the lowest reliability, perhaps due to respondents having Internet sites of primary choice, rather than a high level of usage across several sites. A hypothesized lack of correlation between traditional domains of the gay community and the Internet did not appear: correlations between the Internet measure and the other measures were positive and significant, but among the lowest correlations obtained between the community measures, ranging from 0.06 to 0.24. Those who use the Internet extensively are less likely to be involved in other aspects of the community. Sexual risk was associated with high social engagement at sexual meeting sites and with Internet use. Gay community involvement, including the Internet community, may be complex and associated with both increase in HIV sexual risk behaviors (by measuring use of sexual risk sites) and preventive measures (HIV testing).     

Gambling on Electronic Gaming Machines in Germany: An Age-Period-Cohort Analysis

To provide insights into etiological factors of gambling at the population level, it is critical to document the separate contributions of biological aging, period influences, and birth cohorts on observed temporal trends in gambling. This study investigated age, period, and cohort effects on prevalence rates of electronic gaming machine (EGM) gambling in Germany. We used data from a series of repeated cross-sectional surveys from the Federal Centre for Health Education covering the period 2007–2015. A total of 53,005 participants were surveyed about their past-year participation in EGMs. Using the intrinsic estimator, we disentangled the separate effects of age (16–17 to 64–65 years), period (2007, 2009, 2011, 2013, 2015), and birth cohort (1941–42 to 1997–98). Age effects were highest for those aged 18–33 (p < 0.001). Period effects were highest in 2013 and lowest in 2015 (p < 0.005). A significant increasing birth cohort effect was evident in cohorts born between 1985 and 1998 (p < 0.005). Implications of these results are discussed with regard to the vulnerability of younger ages to gambling, period changes in the regulatory framework of Germany, and differential cohort vulnerability of the Millennial generation due to early-life video gaming experiences.     

Generalized estimating equations by considering additive terms for analyzing time-course gene sets data

Time-course gene sets are collections of predefined groups of genes in some patients gathered over time. The analysis of time-course gene sets for testing gene sets which vary significantly over time is an important context in genomic data analysis. In this paper, the method of generalized estimating equations (GEEs), which is a semi-parametric approach, is applied to time-course gene set data. We propose a special structure of working correlation matrix to handle the association among repeated measurements of each patient over time. Also, the proposed working correlation matrix permits estimation of the effects of the same gene among different patients. The proposed approach is applied to an HIV therapeutic vaccine trial (DALIA-1 trial). This data set has two phases: pre-ATI and post-ATI which depend on a vaccination period. Using multiple testing, the significant gene sets in the pre-ATI phase are detected and data on two randomly selected gene sets in the post-ATI phase are also analyzed. Some simulation studies are performed to illustrate the proposed approaches. The results of the simulation studies confirm the good performance of our proposed approach.     

Testing of homogeneity of variance and autocorrelation coefficients of nonlinear mixed models with AR(1) errors based on M-estimation

Homogeneity of between-individual variance and autocorrelation coefficients is one of assumptions in the study of longitudinal data. However, the assumption could be challenging due to the complexity of the dataset. In the paper we propose and analyze nonlinear mixed models with AR(1) errors for longitudinal data, intend to introduce Huber's function in the log-likelihood function and get robust estimation, which may help to reduce the influence of outliers, by Fisher scoring method. Testing of homogeneity of variance among individuals and autocorrelation coefficients on the basis of Huber's M-estimation is studied later in the paper. Simulation studies are carried to assess performance of score test we proposed. Results obtained from plasma concentrations data are reported as an illustrative example.     

Goodness-of-Fit Testing for the Newcomb-Benford Law With Application to the Detection of Customs Fraud

The Newcomb-Benford law for digit sequences has recently attracted interest in antifraud analysis. However, most of its applications rely either on diagnostic checks of the data, or on informal decision rules. We suggest a new way of testing the Newcomb-Benford law that turns out to be particularly attractive for the detection of frauds in customs data collected from international trade. Our approach has two major advantages. The first one is that we control the rate of false rejections at each stage of the procedure, as required in antifraud applications. The second improvement is that our testing procedure leads to exact significance levels and does not rely on large-sample approximations. Another contribution of our work is the derivation of a simple expression for the digit distribution when the Newcomb-Benford law is violated, and a bound for a chi-squared type of distance between the actual digit distribution and the Newcomb-Benford one.