给定度序列图的覆盖成本和反向覆盖成本的研究

具有n个顶点且度序列为(m,2,…,2,1,…,1)(1的重数为m)的连通图不止一个(这些图均为树),而每个树对应唯一一个段序列(l₁,l₂,…,l_m).通过对任意一树移动最长段的悬挂点到最短段悬挂点的方式得到另一树,比较前后两树的覆盖成本和反向覆盖成本,给出了具有最小覆盖成本和反向覆盖成本的极树,并且进一步给出了取得最小覆盖成本和反向覆盖成本的顶点.     

数量折扣契约下基于成本分担的供应链突发事件协调应对

突发事件会增加供应链成本,如何进行成本分担是决定供应链能否协调应对突发事件的重要因素.用参数分别描述市场需求剧增时增加的生产成本和市场需求剧减时发生的多余产品处理成本,在数量折扣契约基础上,研究突发事件发生后制造商的最优批发价格和零售商的最优订货量,分析其影响因素比较突发事件发生前后包括市场剧增与市场剧减两种情况下的差异,并给出了数值算例.结果表明,成本分担系数和市场需求分布及其变化都会影响最优批发价格和最优订货量,只要根据市场需求变化相应调整契约参数并合理分担由突发事件增加的成本,通过数量折扣契约供应链就能够协调应对突发事件.     

Analysis of the mean squared derivative cost function

In this paper, we investigate the mean squared derivative cost functions that arise in various applications such as in motor control, biometrics and optimal transport theory. We provide qualitative properties, explicit analytical formulas and computational algorithms for the cost functions. We also perform numerical simulations to illustrate the analytical results. In addition, as a by‐product of our analysis, we obtain an explicit formula for the inverse of a Wronskian matrix that is of independent interest in linear algebra and differential equations theory. Copyright © 2017 John Wiley & Sons, Ltd.     

丙烯酸水溶液聚合法制备PTFE/PAA/Nafion膜及其性能

采用廉价的多孔聚四氟乙烯(PTFE)膜作为基底, 用少量的Nafion与PTFE膜复合可制备低成本的质子膜. 但疏水性的PTFE膜与亲水性的Nafion膜结合性不佳. 基于此, 本文对疏水性的PTFE膜材料表面进行设计, 先采用丙烯酸对疏水性的PTFE膜表面进行亲水性改性, 再喷涂亲水性Nafion膜, 完成低成本PTFE/PAA/Nafion膜的制备. 实验结果表明, 改性前的PTFE膜材料水接触角为150°, 改性后的膜接触角变为55.6°, 亲水性大幅上升, 膜的机械强度和尺寸稳定性(断裂强度为25.2 MPa, 80 ℃下的溶胀率为11.9%)均优于Nafion117膜, 而 Nafion用量则节省了60%. PTFE/PAA/Nafion膜具有高质子导通率(80 ℃下达到131.9 mS/cm), 接近于Nafion117膜, 最大功率密度可以达到404.2 mW/cm².     

THE THEORETICAL COST OF SEQUENTIAL AND PARALLEL ALGORITHMS FOR SOLVING LINEAR SYSTEMS OF EQUATIONS

ＴＨＥ　ＴＨＥＯＲＥＴＩＣＡＬ　ＣＯＳＴ　ＯＦ　ＳＥＱＵＥＮＴＩＡＬ　ＡＮＤ　ＰＡＲＡＬＬＥＬ　ＡＬＧＯＲＩＴＨＭＳ　ＦＯＲ　ＳＯＬＶＩＮＧ　ＬＩＮＥＡＲ　ＳＹＳＴＥＭＳ　ＯＦ　ＥＱＵＡＴＩＯＮＳＳａｌｍａｎＨ．Ａｂｂａｓ（ＲｅｃｅｉｖｅｄＭａｙ２４...     

Evaluating impacts of fish stock enhancement and biodiversity conservation actions on the livelihoods of small‐scale fishers on the Beijiang River,China

Inappropriate development and overexploitation have seriously degraded aquatic resources in China. Stakeholders identified three fish stock enhancement and biodiversity conservation scenarios for the Beijiang River: S1, increased fish restocking; S2, no fishing season and habitat conservation; and S3, strict pollution control. Potential impacts of these actions on the livelihoods of fishers were evaluated using applied economic modeling. Baseline costs and benefits came from logbooks from 30 fishers and a survey of 90 households in three villages. The financial net benefit for a household was US$1583 (￥11,160) annually, representing a 142% and 387% return on capital and operating costs, respectively. Larger catches associated with S1 and S2 generated a net benefit of US$1651 and US$1822, respectively. Strict pollution control resulting in higher catches (+20%) and lower operating costs (?20%) would increase the net benefit by 15.9% to US$1835 annually. Pollution control would benefit other resource users and is a prerequisite for ecological restoration. Recommendations for Resource Managers

• Stringent pollution control measures are essential to conserve aquatic biodiversity and enhance the livelihoods of fishers but will require considerable public and private sector investment.
• Enhanced fish stocks in the Beijiang River could benefit poor livelihoods but may not be sufficient to lift households out of poverty, aged fishers require government assistance to diversify their livelihoods, access alternative urban employment, and survive with dignity.
• Adopting the economic modeling approach presented here could enable responsible authorities to simultaneously evaluate fish stock enhancement and biodiversity conservation options.
• Broader application of the approach presented here could help ensure small‐scale inland fisheries are managed sustainably and aquatic ecosystems are restored and protected by 2020, in line with Target 6 of the United Nations’ Convention on Biological Diversity Strategic Plan for Biodiversity.

     

考虑溯源系统应用的优质农产品双渠道供应链决策研究

优质农产品溯源系统的引入,既能提升有效供给、缩短流通时间,又能降低流通中的数量损耗和价值损失,由此带来了双渠道供应链系统在投资、销售、定价等方面的系列决策问题。考虑制造商开辟电子渠道、从溯源系统降低流通损耗和提高质量出发,分别构建制造商主导型的双渠道供应链决策模型。通过对比分析应用前后各成员在投资、定价及销售方面的最优策略,得到相关的核心边界值。数值仿真结果表明:核心边界值主要与双重损耗的改善程度及其他参数相关,各成员及系统接受溯源系统的应用成本不同,应用成本对各渠道销量的影响程度亦不相同,但各成员调整定价的应用成本边界值是一致的。     

Pinning synchronization with low energy cost

The pinning synchronization on complex networks with low energy cost was investigated. Two basic problems were considered, in this paper. One is how to achieve synchronization on complex network with weak coupling. Another is how to reduce the energy cost in the process of achieving and keeping synchronization. On the other hand, for a good pinning strategy, the synchronizing speed should also be ensured. In this paper, a switching pinning strategy was proposed to enhance the synchronizing speed. And from the point of view of energy saving, some selected links were strengthened. Theoretical analysis and simulations on different complex networks indicate that the proposed pinning strategy is effective. Compare with conventional existing method, the superiority of our method is significant.     

手机广告链中移动运营商的努力动机研究与仿真

建立了由单手机广告主、手机广告代理商和移动运营商构成的三级广告产业链之间的基于协作的收益共享契约模型,分析了在以移动运营商为主导的手机广告链中,移动运营商的努力动机受收益共享和努力成本补偿参数的影响.采用量化分析和模拟仿真结合的方法,得出契约参数只有在满足一定条件下,移动运营商所做出的最优努力水平投入决策,将使得整个手机产业链收益最大化,实现多方共赢.     

绿色建筑项目管理综合均衡优化研究

绿色建筑凭借其诸多优点,已然成为我国未来建筑发展的新方向,而对绿色建筑的工期、成本和功能进行全面系统研究并进行综合均衡优化,对于促进绿色建筑的发展具有深远影响.在描述各工程活动的成本和持续时间之间、功能和持续时间之间的非线性关系基础上,运用多属性效用函数理论构建了绿色建筑项目的功能一工期一成本综合均衡优化模型,并用遗传算法进行求解,可以得到最佳均衡解.最后通过一个实例验证了优化模型具有良好的科学性和实用性.