克拉申“自然习得顺序假说”对二语习得研究的影响

＂自然习得顺序假说＂作为Krashen二语习得理论的重要组成部分,受到了二语研究者的普遍关注,同时也受到了很多的质疑。探讨＂自然习得顺序假说＂的理论基础,评述其研究方法,并且指出＂自然习得顺序假说＂存在的合理性,有助于进一步的理解该假说对二语教学与研究的指导意义。     

Integrated safety stock optimization for multiple sourced stockpoints facing variable demand and lead time

The safety stock placement problem of a multi-stage supply chain comprising multiple sourced stockpoints is addressed in this paper. Each stockpoint faces variability in its downstream demand and suppliers' lead time. The maximum among these suppliers' lead time is determined by employing concepts of order statistics. It is required to find the fill rate and safety stocks at each stockpoint that leads to satisfying the end customer service level at minimum safety stock placement cost. Hence, the fill rates and the safety amounts are decided from a global supply chain perspective. Two models are proposed; a decentralized safety stock placement model and a centralized consolidation model. The decentralized model finds the safety amounts at each stockpoint required to face its underlying lead time demand variability. The consolidation model finds the consolidated safety amounts that will be kept in the relevant consolidation center at each stage. A Benders decomposition technique is developed to handle the nonlinearity and binary restrictions involved in the safety stock consolidation model. Strategies proposed by the consolidation model achieve 45.2-62% reduction in safety amounts that results in a cost savings ranging between 22.2-44.2% as compared to the strategies proposed by the decentralized model.     

Input Pricing and Market Share Delegation in a Vertically Related Market: Is the Timing Order Relevant?

This paper adds to the literature on the strategic use of managers’ contracts in competition by examining whether market‐share delegation, in which managers receive rewards based on a combination of profits and market share, and the order of moves affect input pricing in a vertically related market. It shows that: (i) input pricing is not affected by delegation form and the order of moves between upstream and downstream firms under quantity competition; (ii) downstream firms obtain the same profit as in the simple Nash equilibrium regardless of delegation forms in a delegation–input price–quantity competition game; and (iii) the upstream monopolist will set input price beforehand regardless of the delegation form. Since the outcomes in our model create higher quantity and lower price in a Cournot product market, it lessens the double‐marginalization problem in such a vertically separated industry.     

汽车行业BTS&BTO混合生产方式的可行模式研究

在指出传统BTS生产模式弊端和现有条件下不具备实施BTO条件的情况下,提出了结合BTS、BTO二者优点的混合生产方式BTS&BTO。并进一步给出了三种可供参考的具体的混合生产方式实施模式:(1)按产品所处生命周期的不同阶段;(2)按不同车型;(3)按产品制造流程。     

Selecting between batch and zone order picking strategies in a distribution center

An order picking strategy in a distribution center (DC) defines the manner in which pickers navigate the picking area to pick items from storage locations. We focus on the problem of selecting between a batch picking and a zone picking strategy. For this problem, we propose a cost model to estimate the cost of each type of picking strategy. In our cost model we consider the effects of pick-rate, picker blocking, workload-imbalance, and the sorting system requirement. Through an example problem, we show how system throughput, order sizes, item distribution in orders, and wavelength affect the picking strategy selection decision.     

基于交易量持续期的流动性研究

本文充分利用我国限价指令驱动市场分笔数据所包含的信息。在交易量持续期的基础上,提出一个符合限价指令驱动市场特征的流动性指标,并从市场微观结构理论出发．选取了非对称信息的若干代理变量,分析非对称信息对市场流动性的影响程度。对万科A、B股的实证结果发现：（1）交易量持续期拥有信息含量,看涨行情会导致交易强度增大,看跌行情则导致较长的持续期。这反映了卖空限制的作用和投资者的追涨行为。（2）非对称信息是影响流动性水平的重要因素,投资者看法差异严重、价格剧烈波动以及长的交易量持续期导致市场流动性降低。     

Managing carbon footprints in inventory management

There is a broad consensus that mankind must reduce carbon emissions to mitigate global warming. It is generally accepted that carbon emission trading is one of the most effective market-based mechanisms to curb the amount of carbon emissions. This paper investigates how firms manage carbon footprints in inventory management under the carbon emission trading mechanism. We derive the optimal order quantity, and analytically and numerically examine the impacts of carbon trade, carbon price, and carbon cap on order decisions, carbon emissions, and total cost. We make interesting observations from the numerical examples and provide managerial insights from the analytical results.     

政治系统与法律系统对于技术风险的决策观察

德国社会学家尼古拉斯·卢曼的社会系统论和二阶观察理论所提供的社会建构论框架,有助于我们从技术、时间、知识、决策等维度厘清技术风险形成的复杂社会机制,促进我们对政治系统和法律系统中的技术风险管制活动进行反思性观察。政治系统通过政策性决策活动规划和控制技术风险的努力,本身也会导致决策风险,政治系统因此发展出令规制失灵而被社会遗忘的应对能力;法律系统内部发展出来的风险预防原则,其功能不在于增加社会的安全水平,而是作为一种程序性反应机制,吸收因科学技术后果的不确定性所导致的环境复杂性。     

代际传承背景下家族企业继任二代创新投入水平研究——基于差序格局视角

利用2004—2018年1074个家族企业年度样本的非平衡面板数据,基于"本土情景"的差序格局视角,实证考察继任二代履新后创新投入水平。研究结果表明,限定其他条件,继任二代在以创立一代为中心的差序格局中关系越强,履新后创新投入水平越低。进一步引入家族企业异质性发现,创立一代"离而不休"会强化差序格局与创新投入之间负相关关系,即对创新水平产生抑制作用;而政企关联和非家族成员高管介入,均会弱化差序格局与创新投入之间负相关关系,即对创新水平产生促进作用。     

事业单位财务支出要立章有序

事业单位的财务支出是管理工作的核心,合理地控制支出必须依据会计法规做好预算,贯彻勤俭节约的方针,提高资金使用效益。财务列支中应遵循“先发工资、保障运转、实施奖金、促进发展”,即“一工资、二运转、三奖金、四发展”的主次先后有序的排列,这是合理而便于操作的章法。