中国港口煤炭进出口格局演变及动力机制

中国作为煤炭生产和消费的大国,保障煤炭供应是国民经济建设的战略性任务,并影响着国家运输网络构建与进出口贸易。本文在回顾20世纪70年代末期以来中国煤炭进出口发展过程的基础上,刻画了中国从煤炭净出口国向净进口国转变及进出口关系的演变过程;详细分析了中国港口的煤炭进口和出口吞吐量格局的演变过程、基本特征及区域集聚性,认为近年来中国煤炭进出口“南进北出”格局向“南进北出又北进”格局迅速转变;进而绘制了中国煤炭进口的国别网络和中转配送网络,指出部分沿海港口成为煤炭一程接卸和二程配送的枢纽。然后,从煤炭供需关系与耗能产业扩张、煤炭产业政策、市场价格机制、运输瓶颈与生态文明建设等因素,深入分析了中国煤炭进出口格局快速演变的动力机制,并指出中国煤炭进口量的近期爆发性增长是一种短期市场行为,未来仍将保持在高位,但增长速度将下滑。     

"十一五"期间我国高职教育规模发展途径及应注意的问题

“十一五”期间,我国高职教育的规模仍将不断发展。强化特色,进一步落实办学自主权,划转部分第三层次的普通高校举办高职教育等是高等职业教育规模发展的重要途径。在高职教育规模发展过程中还要注意规模与质量、就业之间的关系,注意合理构建高职教育的层次结构,完善高职教育的专业布局,实现高职和中职的有效衔接。     

关于四种弱BCI-代数及其可分配性

引入比BCI-代数条件更弱的四种弱BCI-代数,讨论它们的等价条件,并给出弱BCI-代数的一种二元运算“＋”：x＊y=x＋（x＊y）,讨论了与这种运算相关的可分配性,进而四种弱BCI-代数在可分配下得到统一．     

改善跨栏跑周期节奏的标记法教学实验研究

在跨栏跑技术教学中 ,根据优秀运动员起跨、下栏和栏间各步步长以及所占栏距的百分比值 ,确定学生不同栏距各步步长的比例分配 ,用标记法给以限定 ,并通过抓两腿配合时机掌握跨栏步技术 ,对栏间跑的节奏产生良好影响 ,建立较合理的跨栏跑周期节奏 ,并通过教学实验得以验证     

基于ArcGIS的多温区冷藏车辆路径优化

为降低冷链物流成本,研究多温共配模式下生鲜农产品冷链配送问题。采用多温区冷藏车,构建考虑运输成本、货损成本、制冷成本的路径优化模型,利用遗传算法对算例进行求解,借助ArcGIS规划最短路径。算例结果显示,与传统配送模式相比,多温共配模式可减少2辆冷藏车的调度,总成本降低34. 1%,实际运输距离缩短54. 1%。多温共配模式可有效解决生鲜农产品配送小批量、多品种、高成本的问题。     

需求不确定情况下沿海燃料油供应鲁棒优化

针对沿海地区燃料油供应问题,制定燃料油配送方案,设计配送航线和配送量使运输成本和库存成本最小,同时考虑需求不确定的情况,使需求发生一定变动时原方案依旧可行。与不考虑需求不确定的供应方案相比,使用鲁棒优化方法得到的结果可靠性更强,发生缺货的可能更小。由于需求不确定情况下存在的二次约束严重影响模型的求解效率,提出一种两阶段求解方法来分解问题,使求解效率得到明显提高。对于存在需求不确定情况的供应系统,决策者使用该鲁棒优化模型时,可以根据风险偏好并通过调整参数最大限度地提高供应方案的可靠性。     

基于新鲜度和配送成本的易腐食品配送路径

为解决企业在制定易腐食品配送计划时难以权衡配送总成本与交付产品的新鲜度的问题,建立以配送总成本最低和交付产品平均新鲜度最大为目标,带时间窗的易腐食品配送路径规划模型。采用自适应差分进化(differential evolution,DE)算法求解模型,通过数值算例验证模型和算法的有效性。与基本DE算法和基本蚁群算法的求解结果进行对比,自适应DE算法的求解结果更优,收敛速度更快。求得的帕累托解集表明配送总成本与交付产品平均新鲜度相悖,增加少量的配送成本可以使交付产品的平均新鲜度得到大幅提升。对易腐食品保质期、时间窗宽度和车辆装载量进行灵敏度分析,为企业在不同配送情景下在配送总成本与交付产品的平均新鲜度之间的权衡提供参考。     

我国竞技体育明星广告代言收入归属与分配问题研究

近年来,我国体育明星广告代言收入归属与分配的纠纷层出不穷,影响了运动员、运动队乃至整个体育事业和体育产业的发展.回顾了学界和社会对该类事件的观点及其转变过程,梳理了相关规章制度的修订变化,并基于运动员培养方式的不同,对国家队包办模式、运动员单飞模式和社会资本参与模式下的体育明星广告代言收入归属与分配问题分别进行讨论.通过与娱乐明星的比较,汲取其在合同和经纪人方面的有益经验.指出,应建立健全法律法规,规范体育明星代言收入的归属与分配;在运动员分类管理的基础上,对合同进行明确细化;大力发展职业体育经纪人产业,促进体育产业发展.     

Social inclusivity,cultural diversity and online film consumption

It has been argued that the circulation of film online is a “democratising process”, evident in the breadth and depth of international film now available online, and in the greater ease of access to this content for audiences across the world. This is seen by some to present greater commercial opportunities for film-making from countries marginalised by previous distribution networks, and to foster a more globally diverse and inclusive film-viewing culture, with particular benefits for diasporic populations. Others, however, have pointed to the way in which audiences’ engagement with film online may be constrained by the economics and technology of online distribution and cultural competencies rooted in social stratification. These factors may limit how and what audiences watch, extending beyond issues of physical access to those of cultural access. As such, they raise questions regarding the demographic composition of the audience for online methods of film distribution and different types of international film. We lack sufficient understanding of these issues, however, due to the limited emphasis upon socio-demographic variables in existing academic research into online film consumption, and the limited consideration of particular film content in relevant market research. This article uses original audience research to interrogate the extent to which online distribution is able to connect audiences to a diversity of international film in comparison to other methods of distribution. It also considers some of the socio-demographic characteristics of the audiences for different methods of distribution and types of international film. In doing so, the article grants us a clearer understanding of the degree to which online film distribution fosters diversity and inclusivity through the connections it facilitates between audiences and content.     

Effects of false-start disqualification rules on response-times of elite-standard sprinters

The 100 ms ruling for false start disqualification at athletic competitions governed by the International Association of Athletics Federations has been in force since the early 1990s. Throughout this period, there have been marked changes to the rules that govern the disqualification of athletes from sprint events incorporating starts from blocks. This study analysed all available World and European Championship response-time (RT) data from 1999 to 2014 to examine effects of rule changes on competition RT at major championships. The exponentially modified Gaussian distribution was used to model RT and make comparisons relative to athletes’ sex, ruling periods and competition rounds. Revised RT thresholds of 115 ms and 119 ms were identified for men and women, respectively, indicating that the current 100 ms rule could result in some false starts not being detected in competitive athletics. The study proposes that when using existing International Association of Athletics Federations approved systems, the false start detection threshold should be increased and that men and women athletes should have different thresholds because of substantial evidence of a sex-based difference in RT in elite-standard athletes.