一种带辅助译码比特的Polar码译码方法

在传统的Polar码译码的基础上，引入辅助译码比特，构造了一个辅助的Polar码字以提高译码性能。辅助比特由信道选择辅助窗口内的信息位决定。接收端如译码失败，将进行二次译码尝试。译码方案分两阶段进行：基于相同结构的扩展生成矩阵，将辅助译码比特译出；结合译出的辅助比特，对原码字进行译码，提高译码成功率。仿真结果显示，使用所提方法进行译码，其译码性能明显优于普通串行抵消译码方法；与两种传统的自动重传请求方案相比，能分别获得1 dB和1.9 dB的性能增益。     

农产品供应链重构风险传导SIR建模与仿真研究

[目的]利用动力学SIR模型模拟农产品供应链重构内生风险传导过程,以期在有效把握核心重构风险传导规律基础上为整体管控重构进程风险提出前瞻性思路。[方法]基于农产品供应链重构风险整体构架和重构进程风险传导复杂网络,以湖北省243家大型连锁超市生鲜农产品供应链2007—2017年重构样本数据为研究对象,建立重构进程内生风险传导SIR模型和规划演化模式,利用Matlab软件对模型仿真得到有效管控状态下演化趋势。[结果]在以战术性重构为主导组织结构战略性重构中进程风险传导安全边际X1s超过50%,决定了其净风险阈α0(i)、β0(i),相应的业务单元和功能模块重构进程风险预警和风险恢复能力提高值是主控指标,对进程风险传导感染率x1(i)和恢复率x2(i)起主导作用。[结论]近年来土地流转驱动农产品供应链重构中组织结构重构整体具有战略性,在以战术性重构为主导风险传导管控中重点应加强业务单元和功能模块重构进程在重构易感状态(S)、感染传播状态(I)管控能力,能有效降低波动幅度。     

Rural school access and the agricultural transformation

Improving children's access to primary and secondary education is a strategic goal for many global development agencies and government policymakers. Nevertheless, there is relatively little research examining how changes in rural school supply affect future labor markets. We leverage variation in the timing and location of secondary school construction in Southern Mexico to identify the effects of school supply on labor outcomes. We find that school construction increases expected education for school-aged children by about 4 years and raises the share of years working in the nonagricultural sector between the ages of 18–22 by 29.8 percentage points. The magnitude of the effects on share of years doing nonagricultural work is smaller for individuals from homes where an indigenous language is spoken. Our findings indicate that rural school construction in less-developed countries can accelerate the transformation from agricultural to nonagricultural economies, but there may be heterogeneous effects across socioeconomic groups and ethnicities.     

The role of intermediaries in establishing a sustainable supply chain

In sustainable supply chain management, buyers may use intermediaries to bridge exchanges with suppliers when knowledge of suitable sustainability practices is weak and in need of facilitation. Understanding how supply chain intermediaries perform this role and what happens when intermediation is no longer needed is important in establishing more sustainable supply chains. Two supply chain intermediaries have been investigated with the resulting case study evidence analysed using the Gioia methodology. The findings suggest supply chain intermediaries add value to the buyer-supplier exchange by facilitating sustainability-related information transfer, knowledge development, risk management and improved capabilities. For example, specific practices such as corrective action reports, often managed by the intermediary, underpin the development of a sustainable supply chain. When the intermediary is no longer needed, they become disintermediated from the specific buyer-supplier exchange but may be re-employed in a new triadic relationship in the future with previous parties. This provides positive spill-over effects through intermediation–disintermediation–post-intermediation cycles for both the buyer and supplier populations and for broader society. Overall, the findings highlight the value of the transient position of supply chain intermediaries in establishing sustainable supply chains and the intended consequences of their involvement.     

Implementing sustainable purchasing and supply management (SPSM): A Delphi study on competences needed by purchasing and supply management (PSM) professionals

This research is about a Delphi study that was conducted in the context of the development of a competence model for sustainable purchasing and supply management (SPSM). Based on the findings of a systematic literature review (SLR), it addresses the research gap in this area with the aim to foster the integration of sustainability in purchasing and supply management (PSM) in higher education and in professional training approaches for PSM professionals. The qualitative study was conducted with 16 Delphi experts in the field of PSM and sustainability, applying the critical incident technique (CIT). Together with the findings of the SLR, it led to a specific set of SPSM competences. The theoretical background is based on PSM research, educational sciences and organizational psychology.     

Mortgage market credit conditions and U.S. Presidential elections

Voters punish incumbent Presidential candidates for contractions in the county-level supply of mortgage credit during market-wide contractions of credit, but do not reward them for expansions in mortgage credit supply in boom times. Our primary focus is the Presidential election of 2008, which followed an unprecedented swing from very generous mortgage underwriting standards to a severe contraction of mortgage credit. Voters responded to the credit crunch by shifting their support away from the Republican Presidential candidate in 2008. That shift was large and particularly pronounced in states that typically vote Republican, and in swing states. Without it McCain would have received half the votes needed in nine crucial swing states to reverse the outcome of the election. We extend our analysis to the Presidential elections from 1996 to 2012 and find that voters only react to contractions, not expansions, of credit, and reactions are similar for Democratic and Republican incumbent parties.     

基于供应链管理的发电企业物资采购研究

物资采购是企业管理中极其重要的组成部分,运用合理的采购模式不仅可以提高工作效率,而且还能降低成本。从这一点出发,论文分析了供应链管理的内容及内涵,并根据准时采购、全球采购和集中采购的模式提出发电企业供应链管理策略。     

Money,Asset Prices,and the Liquidity Premium

This paper examines the effect of monetary policy on the market value of the liquidity services that financial assets provide, known as the liquidity premium. The theory predicts that money supply and nominal interest rates have positive effects on the liquidity premium, but asset supply has a negative effect. The empirical analysis with U.S. data confirms the theoretical predictions. The theory also proposes that the liquidity properties of assets can cause negative nominal yields when the money holding cost is low and liquid assets are scarce. The suggestive empirical findings in Switzerland to support this theoretical result are presented.     

分散决策下的双渠道供应链补偿策略——基于消费者渠道选择行为

为了有效解决由于对消费者的争夺从而引发的渠道之间关于定价、服务水平、利润等方面的冲突,基于消费者渠道选择行为,构建了网络直销市场与传统零售市场需求模型和双渠道供应链利润模型,运用Stackelberg模型,在制造商与零售商实施分决策时,通过制造商对零售商实施补偿激励前后的对比,分析了消费者渠道选择行为对网络直销渠道和传统零售渠道定价、制造商与零售商利润以及供应链总利润的影响,并求得最优定价及制造商的最优补偿额度和零售商的最优销售努力水平,进行了不同情况下的双渠道供应链利润的比较分析。结果表明,无论制造商是否实施补偿激励,都应随着网络消费者比例的增加而增加其网络直销价格;零售商的零售渠道价格应根据网络消费者比例的增加先降低到一定水平后再提升。当更多的消费者选择网络直销渠道时,制造商的补偿激励水平和零售商的销售努力程度均会下降。制造商应提高其补偿水平,进而激发零售商提高销售的努力水平,并使双方利润及供应链总利润最大化。研究结果为基于消费者选择行为的供应链补偿研究提供了新方法,对双渠道的供应链补偿研究有借鉴意义。     

Is Supply's Actual Contribution to Sustainable Development Strategic and Operational?

This paper addresses the issue of how sustainable supply practices are actually used as a leverage for sustainable development (SD). In order to assess the level of sustainable supply management within an organization, the authors have reviewed the literature extensively and then developed a five‐step maturity model around five management dimensions. A qualitative exploratory approach based on two detailed case studies of organizations whose reputation for SD is recognized internationally has been used. This methodology allowed us to show (1) how sustainable supply practices could be used as a leverage for an organization's sustainable development approach and (2) that sustainable supply practices still have quite a distance to go with regards to the maturity model for sustainable supply, even in organizations that are often mentioned as leaders in the SD area. In these organizations, managers still emphasize environmental considerations, while neglecting practices that would make it possible to reach the three SD objectives simultaneously. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment