基于完成难度系数的订单插单问题

引入订单完成难度系数的概念,提出基于订单完成难易程度的两阶段多属性决策方法．采用灰色关联度方法求解订单完成难度系数,以订单综合权重与其各影响因素权重偏差最小为目标建立优化模型,求得各待插订单的综合权重向量获得最优插单序列．同时通过算例验证了算法的有效性．     

Calving difficulty and stillbirths of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red

Pure Holstein cows and Normande/Holstein, Montbeliarde/Holstein, and Scandinavian Red/Holstein crossbred cows were compared for calving difficulty and stillbirth rates. Scandinavian Red was a combination of Norwegian Red and Swedish Red. All cows calved from June 2001 to August 2004 at 7 commercial dairies. Statistical models for analysis included effects of herd-year-season of calving and sex of calf in addition to breed of sire and breed group of dam. Male calves had significantly more calving difficulty and stillbirths than heifer calves. First-calf Holsteins bred to Holstein, Brown Swiss, Montbeliarde, and Scandinavian Red bulls were used to determine effects of breed of sire. Calves sired by Scandinavian Red bulls (5.5%) and Brown Swiss bulls (12.5%) had significantly less calving difficulty than calves sired by Holstein bulls (16.4%) from Holstein first-calf heifers. Also, fewer stillbirths resulted from use of Scandinavian Red bulls (7.7%) compared with use of Holstein bulls (15.1%) for first-calf Holstein heifers. Scandinavian Red-sired calves (2.1%) had significantly less calving difficulty than Holstein-sired calves (8.4%) for multiparous Holstein dams. Non-Holstein breeds of sire had significantly fewer stillbirths than Holstein sires when mated to multiparous Holstein dams. To determine the effects of breed of dam, 676 pure Holsteins, 262 Normande/Holstein, 370 Montbeliarde/Holstein, and 264 Scandinavian Red/Holstein crossbred virgin heifers that had been bred to Brown Swiss, Montbeliarde, and Scandinavian Red bulls were utilized. All groups of crossbred cows had significantly less calving difficulty at first calving than pure Holsteins (3.7 to 11.6% vs. 17.7%). Furthermore, Montbeliarde/Holstein (6.2%) and Scandinavian Red/Holstein (5.1%) crossbreds had significantly lower stillbirth rates at first calving than pure Holsteins (14.0%).     

关于林纸一体化工程建设的探讨--重要意义实施难点前景展望--

阐述了发展林纸一体化的意义和必要性,结合我国的国情,对林纸一体化实施的难点和前景作了深入探讨.     

玻纤增强PVC复合材料的研究现状及其型材的开发难点

介绍了玻纤增强PVC材料的实验室研究和工业化生产现状,以及玻纤增强PVC型材的开发难点。     

蜀河水电站索道桥概预算编制难点及解决方法

在公路桥梁工程概预算编制工作中,桥梁工程的计价比较繁琐,而且编制内容也相当复杂,此外现行的96定额(从1996年7月1日开始执行)实际上反映的是中国1990年前后的公路造价和施工水平,与今天的施工技术和施工水平相比,均缺乏相应配套的定额,需要根据不同的情况编制相应的补充定额。结合蜀河索道桥工程概预算编制中积累的经验,简述编制索道桥工程概预算的难点、解决方法及注意的问题。编制过程中的创新点,值得类似工程借鉴。     

Task difficulty, risk, effort and comfort in a simulated driving task—Implications for Risk Allostasis Theory

Risk Allostasis Theory states that drivers seek to maintain a feeling of risk within a preferred range [Fuller, R., 2008. What drives the driver? Surface tensions and hidden consensus. In: Keynote at the 4th International Conference on Traffic and Transport Psychology, Washington, DC, August 31–September 4, 2008]. Risk Allostasis Theory is the latest version of Task-Difficulty Homeostasis theory, and is in part based on the findings of experiments where participants were asked to rate the task difficulty, feeling of risk and chance of collision of scenes shown in digitally altered video clips [Fuller, R., McHugh, C., Pender, S., 2008b. Task difficulty and risk in the determination of driver behaviour. Revue européenne de psychologie appliqée 58, 13–21].The focus of the current research was to expand upon the previous video based experiments using a driving simulator. This allowed participants to be in control of the vehicle rather than acting as passive observers, as well as providing additional speed cues. The results support previous findings that ratings of task difficulty and feeling of risk are related, and that they are also highly related to ratings of effort and moderately related to ratings of comfort and habit. However, the linearly increasing trend for task difficulty and feeling of risk described by the previous research was not observed: instead the findings of this experiment support a threshold effect where ratings of risk (feeling of and chance of loss of control/collision), difficulty, effort, and comfort go through a period of stability and only start to increase once a certain threshold has been crossed. It is within the period of stability where subjective experience of risk and difficulty is low, or absent, that drivers generally prefer to operate.     

关于改善供热费难收缴的几点设想

随着寒冷冬季的来临,供热费收缴困难的关隘,再次摆在了供热公司的面前。通过对几个供热集团和供热电厂的调查研究,总结归纳了几点解决供热收费难的办法,希望有助于改善热费收缴困难的局面,并提高热费收缴率。     

高压输电线路的导线换线施工

针对输电线路中常见的换线施工工艺做了一定的探索研究,解决了以往施工需将导线放到地面开断后人工回收,造成地面附着物损坏破坏环境的难题;全过程导线换线操作在空中进行,利用机械设备在线路两端牵放操作,旧导线在牵引场集中回收,对于跨越公路、河流、带电高压线路等本工艺优势明显,施工速度快,安全可控性强,节约人力资源,经济效果显著。