钢桶螺纹盖机器人旋紧控制系统

为了解决人工操作或机械半自动化旋紧钢桶螺纹盖所带来的弊端,提出采用工业机械臂对其进行自动旋紧。运 用EtherCAT总线技术,通过CoDeSys开发软件,设计开发了一种机器人旋紧控制系统,使得机器人可以对钢桶螺纹盖进 行自动抓取、定位和旋紧,完成相应的工序。该设计实现了钢桶螺纹盖旋紧的自动化生产,提高了生产效率和加工质量。     

A time series model with random coefficients

There are many time series applications where an experi­menter observes the simultaneous responses of several sub­systems over time. In these instances one is often not interested in the parameters of individual subsystems, but rather in an overall characterization of the system in question. Under the assumption that subsystems are independent and first order autoregressive, the present paper presents two methods for estimating the distribution of the subsystem coefficients.     

Contraceptive Responsibility among Male University Students

Abstract

This paper assesses the male contribution to contraceptive mismanagement and unwanted pregnancy. The subjects were 109 students at the University of Melbourne. A high incidence of risk-taking was reported, and almost one-fifth of the sexually experienced men stated that they had been involved in an unwanted pregnancy. A small group of these reported more than one such incident. The underlying reasons for poor contraceptive technique seemed to be related to two beliefs: that contraception is a female responsibility, and that sexual intercourse should be entirely spontaneous and unplanned.     

Stimulant medication use, misuse, and abuse in an undergraduate and graduate student sample

In this study, the authors investigated the characteristics of use, misuse, and abuse of stimulant medication (primarily methylphenidate and variants) among students at a northeastern US university. Researchers sent an invitation to take an Internet survey to student e-mail addresses and passed 150 paper surveys in undergraduate classes, analyzing 1,025 (975 electronically) returned surveys. Sixteen percent of respondents reported abusing or misusing stimulant medication. Ninety-six percent of respondents who specified a medication preferred to abuse or misuse Ritalin. Men and women reported similar use patterns. Most respondents who abused or misused stimulant medication swallowed pills; 40% used intranasally. Reasons for abusing or misusing stimulant medication included improving attention, partying, reducing hyperactivity, and improving grades. Consistent with previous studies, results suggest that abuse of stimulant medication is a concern on college campuses. The results point to various reasons for and methods of abusing and misusing stimulant medication that may direct future research, prevention, and intervention.     

Return variances of selected German stocks

Models with autoregressive conditional heteroskedasticity are used to describe the behavior of the variance of the rate of return on selected German stocks. The results show that these models are superior to the commonly used process with constant variance due to their increased flexibility in situations of changing volatility.     

Economic machine adjustment in the case of product screening

In the course of the rapid growth in automated manufacturing systems automatic control devices become more and more widespread, especially in electronic industry. A survey in US industry performed 1987 by the American Society for Quality Control has shown that 85% of the organisations used screening procedures. In this paper the results of economic adjustment designs for x-control charts in v. Collani et al. (1989) are extended to the case that all of the produced items are subject to acceptance sampling. A simple algorithm is developed for determination of approximate optimal adjustment designs.     

Covariance structure analysis via specification searches

Iterative model modification (specification searches) has become common practice in applications of covariance structure modeling techniques. The present analysis examines the reliability of a method for carrying out specification searches based on Lagrange multiplier and Wald tests. Results are compared to specification searches performed by means of likelihood ratio tests. Our findings indicate that neither of both methods is significantly superior to the other and that even in connection with very large samples, results from these search procedures can be relied upon only under favorable conditions. The authors therefore suggest the application of specification searches in a more restricted framework in which the parameters in that part of the model that is not subject to the search procedure are fixed. It is demonstrated that this concept enhances the likelihood of success of specification searches significantly.