Stock market volatility forecasting: Do we need high-frequency data?

The general consensus in the volatility forecasting literature is that high-frequency volatility models outperform low-frequency volatility models. However, such a conclusion is reached when low-frequency volatility models are estimated from daily returns. Instead, we study this question considering daily, low-frequency volatility estimators based on open, high, low, and close daily prices. Our data sample consists of 18 stock market indices. We find that high-frequency volatility models tend to outperform low-frequency volatility models only for short-term forecasts. As the forecast horizon increases (up to one month), the difference in forecast accuracy becomes statistically indistinguishable for most market indices. To evaluate the practical implications of our results, we study a simple asset allocation problem. The results reveal that asset allocation based on high-frequency volatility model forecasts does not outperform asset allocation based on low-frequency volatility model forecasts.     

中国零售业自营与联营问题的流通经济学分析

零售业自营与联营之争由来已久，在当前供给侧结构性改革、完善促进消费体制机制以及零售业寻求创新发展的背景下，有必要对这一问题展开进一步的理论探讨。文章结合马克思流通经济理论指出，自营和联营的本质区别在于是商业资本还是产业资本承担商品流通职能，自营和联营并不是非此即彼的互斥关系，但如果零售业完全倚重其中一种模式并在全社会推向极端，则需要反思商业资本和产业资本是否各得其所和高效分工。在中国流通体制变革中，虽然联营模式在特定历史时期帮助众多零售企业渡过生存危机并推进内资零售快速扩张，但发展至今，已呈现零售业普遍联营的情况，使零售业整体面临着制约创新发展的新问题。数字经济为零售业回归自营提供了有利契机，零售企业应充分利用新技术摆脱联营制的路径依赖，依托数字化开展深度自营并全面提升流通效率。     

碳排放交易制度的节能减排路径：效率提升还是结构转型？——来自中国省级数据的准自然实验

以中国2013年以来实行的碳排放交易试点政策作为准自然实验事件，基于2000-2017年中国30个省市的面板数据，运用双重差分法实证检验碳排放交易制度的节能减排效应及影响机制。研究发现，碳排放交易制度有利于实现中国经济“节能”与“减排”的双重目标，并通过了一系列稳健性检验；作用机制检验表明，能源效率提升和能源结构转型都是碳排放交易制度实现节能减排目标的重要路径；能源效率提升在碳排放交易制度实现“节能”和“减排”中分别发挥了10.19%和5.93%的作用，而能源结构转型分别发挥了48.87%和52.95%的作用。这意味着中国碳排放交易制度实现节能减排的主要动力来自能源结构转型，而非能源效率提升。能源结构转型涉及问题更加宏观和深层，这为中国加快推进节能减排进程，特别是完成2030年碳达峰和2060年碳中和的国际承诺提供政策启示。     

基于AD9361的掌上型LTE RRU设计与开发

当前小体积远端射频单元（Remote Radio Unit,RRU）主要是皮站级别的Pico-RRU，其重量和体积仍然难以满足掌上型的要求。为此，采用高集成度的AD9361芯片来实现长期演进（Long Term Evolution，LTE）宽带收发信机功能，配合时钟同步模块、放大器模块和控制接口电路等一起构建低成本的掌上型RRU。主要解决了基于AD9516的时钟同步、低相位噪声设计和高灵敏度接收机设计三个技术难点，成功实现了掌上型、高性能、低成本的设计目标。整个RRU样机尺寸为18 cm×10 cm×2 cm，质量约500 g，量产成本千元以内。测试表明，该RRU下行误差向量幅度（Error Vector Magnitude，EVM）小于3%，优于3GPP要求的8%；10 MHz带宽时上行接收机灵敏度优于3GPP要求的-93.5 dBm。     

Cross‐Functional Integration: Concept Clarification and Scale Development

The centrality of cross‐functional integration (CFI) to supply chain theory and practice has long been recognized. Yet researchers continue to struggle with consistently defining or measuring the CFI construct, thus limiting the utility of CFI research. This research develops (1) a comprehensive definition of CFI that synthesizes previous supply chain research and (2) a valid set of scale items that measure the conceptual domain outlined by this definition. The goal is to build a common foundation for extending knowledge on CFI's antecedents and consequences, and ultimately to improve scholars’ ability to guide a broader practitioner community still struggling to achieve integration in their organizations.     

国家科技创新能力时空差异性评价

科技创新规模扩张和科技创新效率提升是增强国家科技创新能力的两条关键途径。基于现有研究鲜有结合科技创新规模和科技创新效率开展国家科技创新能力评价的现状，采用因子分析法，系统筛选国家科技创新规模影响因素，并结合科技创新效率影响因素，完善国家科技创新能力评价指标体系，通过构建DEA Malmquist指数模型，评价不同时期国家科技创新效率变化指数，以及中国与全球10个国家科技创新能力的时空差异性。研究表明，R&D投入强度、R&D研究人员、专利申请量、科技期刊文章数、高科技产品出口额占制成品出口总额的百分比、科技创新效率是影响国家科技创新能力的关键指标；1991-2014年中国科技创新能力水平呈指数增长态势，有力提升了国家科技实力；全球10个国家科技创新能力水平除日本出现一定波动外，其余九国整体呈小幅递增态势。     

Advancing environmental productivity: Organizational mindfulness and strategies

This study investigates the importance of mindfulness‐based organization systems and policies on the organization's continuous efforts to become a greener company. The study is devised as a pooled cross‐sectional time series analysis of productivity in energy consumption, water utilization, and waste generation and recycling of U.S. companies. The data set taken from U.S. Newsweek 500 recorded 600 companies dispersed into 63 industries during the period of 2012–2014 and provided 1,498 company–industry–year observations. The study found that systems and policies (e.g., deployment of third‐party auditors for its environmental metrics report; linkage of the remuneration of company's senior executive team with the achievement of environmental performance targets; and establishment of a committee at the Board of Directors' level whose mandate includes sustainability of the company in environment‐ and resource‐related matters) connect the company's mindfulness to its effort in improving the environmental quality through the company's productivity in energy consumption, water utilization, and waste generation and recycling. The relationships are positive and significant. Also, systems and policies serve as a motivator for the firm to continue to improve upon the current achievements. The study emphasizes the importance of translating organizational and individual mindfulness into organization policies and systems in order to motivate the organization to continuously improve its productivity in energy consumption, water utilization, and waste generation and recycling leading to improvements in environmental quality.     

Do pensions foster education? An empirical perspective

The paper examines the effect of population ageing on public education spending. On the one hand, ageing is expected to have a negative effect on education, as an increasing number of retirees results in ‘intergenerational conflict’ and, hence, the condemnation of education expenditure. On the other hand, ageing, in combination with pay-as-you-go pension systems, offers incentives for the working-age generation to invest in the public education of the young in order to ‘reap’ the benefits (that is, higher income tax/contributions) of their greater future productivity. Empirical evidence derived from the application of a fixed effects approach to panel data for OECD countries shows that the increasing share of elderly people has a non-linear effect on education spending. This indicates a certain degree of intergenerational conflict. Nevertheless, we find that future population ageing, which reinforces the mechanism linking public education and pensions, reflects positively on education expenditure. Furthermore, by disaggregating total education expenditure by educational levels, we observe that this effect is led by levels of non-compulsory education, probably as a reflection of the direct connection to labor productivity.     

Using the Pack‐and‐a‐Half Rule to Eliminate Backroom Inventories in Retail Operations

In the retail industry, backroom inventories are typically associated with higher labor costs and greater operational complexity. Thus, retailers look for ways to eliminate backroom inventories. A heuristic used for this purpose is the pack‐and‐a‐half rule which suggests that the shelf space allocated for a product should be at least 50% larger than the case pack quantity in which the product is delivered. Despite its popularity among retailers, the pack‐and‐a‐half rule has been ignored in the academic literature. We introduce the pack‐and‐a‐half rule, assess its impact on a retailer's profits, identify cost, demand, and product characteristics driving this impact, and propose a modification. Based on an analysis of data obtained from a retailer on 1,986 SKUs in 20 categories, we find that the pack‐and‐a‐half rule decreases a retailer's profits, on average, by 10% when applied uniformly across all SKUs. Further, this decrease is significantly affected by product depth, product width, demand elasticity, case pack quantity, and inventory carrying cost. Finally, we develop a set of modifications based on these variables where the pack‐and‐a‐half rule is applied selectively and in a stepwise fashion. These modifications limit the decrease in a retailer's profits to a range between 6% and 7%.     

The Effects of Search-Related and Purchase-Related Mobile App Additions on Retailers’ Shareholder Wealth: The Roles of Firm Size,Product Category,and Customer Segment

Mobile channel additions have been shown to increase consumer-brand relationships, brand satisfaction towards and overall purchasing from a retailer, but what is less apparent is whether shareholders are fully rewarded for retailers’ mobile channel additions. Results from an event study on 115 announcements relating to mobile app additions of publicly traded U.S. retail firms between 2009 and 2016 indicate that the stock market responds generally positively to mobile app additions, but specifically to the two mobile app addition types. Stock market responses to search-related and purchase-related app additions are moderated by firm size, product category, and target customer age. For announcements of search-related apps, the market responds more positively to product retailers than to service retailers, and to small firms than large ones. For announcements of purchase-related apps, the market responds less positively to firms that target younger customers than firms who do not especially target them.