Joint modified block replacement and production/inventory control policy for a failure-prone manufacturing cell

This paper considers a joint preventive maintenance (PM) and production/inventory control policy of an unreliable single machine, mono-product manufacturing cell with stochastic non-negligible corrective and preventive delays. The production/inventory control policy, which is based on the hedging point policy (HPP), consists in building and maintaining a safety stock of finished products in order to respond to demand and to avoid shortages during maintenance actions. Without considering the impact of preventive and corrective actions on the overall performance of the production system, most authors working in the reliability and maintainability domains confirm that the age-based preventive maintenance policy (ARP) outperforms the classical block-replacement policy (BRP). In order to reduce wastage incurred by the classical BRP, we consider a modified block replacement policy (MBRP), which consists in canceling a preventive maintenance action if the time elapsed since the last maintenance action exceeds a specified time threshold. The main objective of this paper is to determine the joint optimal policy that minimizes the overall cost, which is composed of corrective and preventive maintenance costs as well as inventory holding and backlog costs. A simulation model mimicking the dynamic and stochastic behavior of the manufacturing cell, based on more realistic considerations of the real behavior of industrial manufacturing cells, is proposed. Based on simulation results, the joint optimal MBRP/HPP parameters are obtained through a numerical approach that combines design of experiment, analysis of variance and response surface methodologies. The joint optimal MBRP/HPP policy is compared to classical joint ARP/HPP and BRP/HPP optimal policies, and the results show that the proposed MBRP/HPP outperforms the latter. Sensitivity analyses are also carried out in order to confirm the superiority of the proposed MBRP/HPP, and it is observed that for practitioners, the proposed joint MBRP/HPP offers not only cost savings, but is also easy to manage, as compared to the ARP/HPP policy.     

尼尔基水利枢纽工程粘性土分散性分析的研究

尼尔基水利枢纽位于黑龙江省与蒙古交界的嫩江干流上,工程基础可能存在分散性粘土。由于分散粘土对水利工程的危害极大,有必要对该工程使用的土料进行分散性鉴定。本文通过三种试验方法鉴定得出统一结论,判定该批土样为非分散性土。     

浅谈线描在动画专业基础教学中的有效应用

文章分析了线描在动画造型艺术中的优势,并结合教学经验阐述了线描在动画专业基础教学中的有效应用。     

有杆抽油系统诊断方法研究与应用

以有杆抽油系统动力学行为分析为基础,将基础理论研究和应用技术有机地结合起来,建立了考虑悬挂系统弹性的直井和定向井有杆抽油系统诊断模型,研究了基于B/S（Brower/Server）模式的有杆抽油系统故障诊断方法,利用Internet技术和Web技术开发了相应的软件系统, 通过浏览器即可实现对有杆抽油系统快速、准确的故障诊断,并给出了诊断算例,诊断结果验证了该系统的有效性。基于B/S模式的有杆抽油系统故障诊断对避免井下作业的盲目性,提高系统效率,降低采油成本,实现油田企业信息化和提高油井的科学管理水平具有重要意义。     

Racial/ethnic disparity in child welfare systems: A longitudinal study utilizing the Disparity Index (DI)

The purpose of the study is to examine racial/ethnic disparity among children and families that are involved with the child welfare system. Specifically, the authors explore whether or not disparity levels and long-term changes in disparity in California child welfare systems are significant. In addition, the study investigates how county characteristics such as child poverty rates, unemployment rates, and rurality are associated with levels of disparity and changes in racial/ethnic disparity over time. Using a Latent Growth Curve (LGC) modeling approach, the study estimated the trajectories of county-level Disparity Index (DI) scores (Shaw, Putnam-Hornstein, Magruder, & Needell, 2008). African American and Hispanic/Latino children were compared to Caucasian children for two phases of the child welfare process: substantiated allegations and entries, between 2005 and 2008. The results demonstrate that racial/ethnic disparity between African American and Caucasian children was significant at both phases of the child welfare process in 2008. However, disparity between Hispanic/Latino and White children was not significant. Levels of disparity between African American and Caucasian children remained constant over time. Regarding the effects of county characteristics, higher child poverty rates, higher unemployment rates and rurality were related to lower levels of disparity. In addition, unemployment rates were associated with increasing rates of change in entries disparity between African American and Caucasian children. And urbanicity was associated with increasing rates of change in substantiated allegations disparity between Hispanic/Latino and Caucasian children. The study's implications for future research are discussed.     

储层模型正演模拟及AVO 特征研究

为了在多波地震资料解释过程中解决多波信息识别难的问题,基于弹性波正演技术,针对某油田勘探区块的实际储层地质模型,采用高阶交错网格差分技术正演模拟非零偏炮集多波地震记录,并经多波资料处理,得到纵波和转换波CMP 和CCP 叠前含AVA 的动校正道集及叠加剖面。在已知模型的AVA 计算、模型层位参数与正演纵、横波波场关系的基础上,对比研究了正演记录中各储层的纵波和转换波对应关系。对比分析结果表明,数值模拟结果与AVA 分析结果吻合,同一储层的纵波和转换波波场响应有明显差异。     

唐代文化虚拟博物馆设计与实现

唐代是我国历史上极富文化吸引力的时代。通过虚拟现实技术,搭建唐代风格宅院,创设充满唐代生活气息的情境,在其中安排多种文物展品和文化展示,完成一个集漫游、观赏、教育于一体的虚拟博物馆,意图达到传播中国传统文化、增强受众民族自豪感的目的。运用的技术包括三维建模、虚拟现实、交互动画等。     

The Use of Video Modeling,Prompting, and Feedback to Increase Credit Card Promotion in a Retail Setting

We evaluated the use of video modeling, role play, prompting, and feedback to increase credit card promotion by sales associates in a retail setting. We first used the Performance Diagnostic Checklist (Austin, 2000 Austin, J. 2000. “Performance analysis and performance diagnostics”. In Handbook of applied behavior analysis, Edited by: Austin, J. and Carr, J. E. 321–349. Reno, NV: Context Press.  [Google Scholar]) to identify the variables contributing to the poor performance of two sales associates. Based on the results, we developed an intervention package that included a video model, instructional prompt cards, role play, and feedback. During baseline, target employees asked a mean of 26% of customers to enroll in the credit card program. Following intervention, target employees asked a mean of 84% of customers to enroll in the credit card program. Furthermore, employees rated the intervention as enjoyable, as effective, and as a system that they would continue to use. The results illustrate the effectiveness of video modeling, prompting, and feedback in increasing credit card promotions and delivering critical information about the card to daily customers.     

The Effects of Evaluating Video Examples of Staffs' Own Versus Others' Performance on Discrete-Trial Training Skills in a Human Service Setting

Many studies have been conducted evaluating the use of feedback in staff training in organizational settings. Central to this literature has been the use of a variety of forms of feedback, including videotaped feedback. A distinction is outlined between video modeling and a variety of possible video feedback procedures. Previous studies have indicated a possible positive training effect on staff skills from simply being exposed to relevant videotaped performances of those skills or as a result of evaluating video modeled performances. This study evaluated the effectiveness for training teaching skills of having staff evaluate videotaped teaching skills as performed by themselves versus others. The current study results replicate earlier research on the effectiveness of evaluating video models as a training method and do not suggest a difference between observing oneself as opposed to observing someone else. Future research suggestions for the general use of video in training are provided.     

Improving the Quality of Staff and Participant Interaction in an Acquired Brain Injury Organization

Weekly observations of direct-care staff in a facility for persons with brain injury yielded less than optimal interactional style with facility residents. Following an observational baseline, staff were asked to self-rate a 15-min video sample of their interaction behavior with participants on their unit. They were then asked to compare their self-ratings to those of a supervisor, as well as view a video exemplar of appropriate positive interaction behavior. Elements of their interactional style were highlighted and specific feedback was provided on how to improve their performance. Interaction style was then reevaluated via an unobtrusive observer and yielded positive gains for all participants. Subsequent on-the-job feedback sustained performance gains.