一种乘积估计量的研究

在抽样调查中恰当地使用辅助信息可以提高调查精度。当辅助变量x与调查指标y呈负相关关系时,乘积估计是构造总体均值估计传统的方法。本文提出了链式乘积估计量,并且得到了它的均方误差。在一定条件下,链式乘积估计量的效率高于传统估计量,并提供了一个数值例子。     

Effect of product and geographic diversification on company performance: Evidence during an economic crisis

Based on a novel sample of Spanish listed companies from nonfinancial sectors, we explore the effect of product and geographic diversification on company performance during an economic downturn. The study develops comprehensive models to understand the interaction effect of both strategies on company performance. We find a U-shaped geographic diversification–performance relationship and no evidence of a positive effect from product diversification, unless combined with high levels of geographic diversification. The results show that companies improved their performance by combining these strategies. The results are robust after controlling for the endogeneity of both types of diversification. Our findings highlight that geographic diversification is an effective and valuable strategy in economic downturns. Furthermore, this study confirms the importance of the interaction between product and geographic diversification to determine the total effect of product or geographic diversification on company performance.     

The US–China trade war and Phase One agreement

The Trump administration changed US trade policy toward China in ways that will take years for researchers to sort out. This paper makes four specific contributions to that research agenda. The first is to carefully mark the timing, definitions, and scale of the products subject to the tariff changes affecting US–China trade from January 20, 2017 through January 20, 2021. One result was each country increasing its average duty on the other to rates of roughly 20 percent, with the new tariffs and counter-tariffs covering more than 50 percent of bilateral trade. The second contribution is to highlight two additional channels through which bilateral tariffs changed during this period that received less research attention. One tariff change is through product exclusions, another is trade remedy policies of antidumping and countervailing duties. The third contribution is to provide an initial exploration into why China fell more than 40 percent short of meeting the goods purchase commitments set out under the first year of the Phase One agreement. The last contribution is to consider additional trade policy actions—involving forced labor, export controls for reasons of national security or human rights, and reclassification of trade with Hong Kong—likely to affect US–China trade beyond the Trump administration.     

中国人口迁移流动的人力资本替代效应及影响分析

人口迁移流动是改变人口数量和人力资本空间分布格局的重要因素,人口迁移流动造成的人口数量和人力资本空间分布变化是否一致及其对区域经济社会发展的影响是一个需要更加深入研究的问题。本文针对我国人口流动过程中形成的人口素质结构转变进行理论思考和实证研究,探讨其形成的经济原因和造成的经济影响。相关数据显示我国高等教育群体和中等教育及以下群体长期以来一直处于净流向相同的状态,而2013-2015年以来各省陆续出现净流向相反的现象,形成了人口数量和人口素质的替代效应。高等教育人才的净流入地区是经济发达省份、地理条件优越省份以及少数民族自治区,北京、天津、上海、浙江、江苏以及广东省等三大都市圈内的六个省市的高等教育净流入人才占跨省高等教育净流入总人口的绝大多数。人口替代对当地的经济影响表现为三点:第一,改变当地劳动力资源禀赋结构,使高等教育群体及中等教育群体人数的比较优势发生变化;第二,改变地区平均受教育年限,影响地区科技创新能力;第三,拉大地区劳动力收入差距。据此提出两点政策建议:首先,地方省市可以通过市场化的产业结构调整手段控制相应的流动人口群体规模,而不必依靠限制人口流动的政策以及硬性提出人口调控目标来管理流动人口规模。其次,地方政府要做好地区经济规划以及定位,充分认识现在的人口替代对于未来地区创新能力以及劳动力收入差距的影响。     

The Roles of Supply Chain Intelligence and Adaptability in New Product Launch Success

Many new product introductions continue to be unsuccessful, and while researchers have studied product development processes, relatively few studies directly address new product launch. We do so in the present research and posit that supply chain intelligence, defined as technological and competitive knowledge sourced and integrated from suppliers, customers, and competitors, plays an important role in explaining new product launch success. We further employ the knowledge‐based view to theorize that both supply chain adaptability and product innovation capability act as important mediators of the effects of supply chain intelligence on new product launch success and firm financial performance. While the former capability refers to a firm's ability to quickly adjust its supply chain to react to market and product design changes, the latter refers to the firm's proficiency in developing innovative new products. We test hypothesized relationships among these factors utilizing data collected in a survey of 229 U.S. manufacturing firms. Results point to the central role of supply chain adaptability in capturing the benefits of supplier technological intelligence for enhanced product innovation capability, new product launch success, and firm financial performance. In contrast, product innovation capability serves as the generative means by which customer and competitor intelligence is translated into more successful new product launches, which, in turn, produce superior firm financial performance. Overall, these findings contribute to a better understanding of factors that can explain why certain product launches are more successful than others, and offer practical insights for appropriate investments in the development of related knowledge resources.     

Introduction to Innovation WITHIN and ACROSS Borders: A Review and Future Directions

Innovation is an integral part of every firm's ongoing operations. While new product and service creation is an essential task to ensure a firm's immediate success in the marketplace, process and supply chain innovations can also create a unique source of competitive advantage for the future. Encouraging innovative thinking, developing new innovations, and managing the processes by which those innovations are developed are critical aspects of today's firm. Consequently, research which aids in the creation and maintenance of innovative firms is an important topic of inquiry for research communities on innovation management, including the operations management and information systems communities. We review the literature in this important area and offer suggestions for future research on the following topics: innovation within a firm and across the supply chain, technology management, and new product and service development.     

Cost models for evaluating virtual design strategies in multicycle product families

Rapid technological change and increased competition are forcing firms to compress the time it takes to develop product families and rapidly realize innovations among successive family members (models). Competition in rapidly changing high-variety markets requires effective management of design information across successive generations of products as well as in the same product generation. This paper considers two complementary approaches to design information management: virtual design and modular design. Virtual design describes the abstraction hierarchy used to represent product function. Modular design describes the hierarchy of physical realizations of the product and leads to a group technology approach to manufacturing. An analytical model is used to describe the impact of design management strategy characterized by investment in tools and infrastructure for virtual design and group technology on product development costs. This model provides insight into the impacts on costs of the mix of standard and revised parts in a product family. Virtual design has greatest impact on cost when there is a large proportion of parts revision, while group technology has most impact on cost when large numbers of standard parts are re-used. Effective management strategy for high variety rapidly changing products should combine both of these approaches and emphasize compatible organizational methods and technology integration.     

芒硝的产品开发

阐述以芒硝为原料生产多种化工产品的化学反应原理与工艺流程，为芒硝的产品开发提供了技术方法。可供盐矿及乡镇企业参考。     

PDM技术的基本功能与应用

产品数据库管理 (PDM)是现代产品开发环境中成长与发展起来的一项管理数据新技术 .主要阐述了该项技术的基本功能及应用