A pragmatic decision model for inventory management with heterogeneous suppliers

For enterprises, it is imperative that the trade-off between the cost of inventory and risk implications is managed in the most efficient manner. To explore this, we use the common example of a wholesaler operating in an environment where suppliers demonstrate heterogeneous reliability. The wholesaler has partial orders with dual suppliers and uses lateral transshipments. While supplier reliability is a key concern in inventory management, reliable suppliers are more expensive and investment in strategic approaches that improve supplier performance carries a high cost. Here we consider the operational strategy of dual sourcing with reliable and unreliable suppliers and model the total inventory cost where the likely scenario lead-time of the unreliable suppliers extends beyond the scheduling period. We then develop a Customized Integer Programming Optimization Model to determine the optimum size of partial orders with multiple suppliers. In addition to the objective of total cost optimization, this study takes into account the volatility of the cost associated with the uncertainty of an inventory system.     

股指期货交易量与股指现货波动关系研究——来自香港恒生指数的实证

文章以香港恒生股票指数及其期货为样本,研究了股指波动性与指数期货交易量之间的关系。研究结果表明,它们之间存在单向因果关系,股指现货市场的日间价格波动并没有明显增加股指期货的交易,但股指期货的交易量却对指数现货的波动性产生延迟影响,这从一定程度上反映了香港市场股指期货主要被投资者用于套利而不是风险对冲的工具。     

The Impact of Regulation on Cost Efficiency: An Empirical Analysis of Wisconsin Water Utilities

The impact of regulation of efforts to minimize costs has been widely discussed, but remains difficult to measure. The sophisticated regulation of water utilities in Wisconsin allows us to attempt such on assessment since different firms can be under different regulatory regimes (price cap or rate-of-return) in the same geographical area at the same time. To measure the impact of regulation on efficiency, we use a stochastic cost frontier approach defining the unobservable efficiency of a water utility as a function of exogeneous variables. Using a panel of 211 water utilities observed from 1998 to 2000, we show that their efficiency scores can be partly explained by the regulatory framework.     

政府补助、产权性质与定向增发

政府补助效果是学者高度重视的焦点话题。本文以政府补助为切入点,从一级市场、二级市场分别考察定向增发新股的定价效率以及定向增发收益背后的经济逻辑,并采用随机前沿分析法对2007—2017年间获得政府补助且实施定向增发新股的沪深A 股上市公司进行实证分析。结果发现：定向增发新股发行存在溢价现象,新股上市后也存在溢价现象,政府补助加剧了溢价程度,进而导致定价效率降低,且在国有企业中更严重;发行定价泡沫越严重,定向增发收益越高,同时政府补助对定向增发收益能产生积极影响,且在国有企业中更显著。路径检验结果发现：政府补助作用于定向增发收益可能依赖盈余管理、自主创新以及个股成长这三条路径。上述结果表明,政府补助可能被异化为操纵股价的隐形工具,导致政府补助效果“事与愿违”。     

Uncertainty,firm entry,and investment dynamics

Previous macro- and micro-level evidence indicate that fluctuations in idiosyncratic uncertainty have an important effect on investment, both directly and indirectly through financial market frictions. The objective of this paper was to explore, beyond the two traditional and complementary channels, a new one: firm entry. By utilizing a novel and large dataset on Greek firms covering the entire economy over the period 2000–2014 and employing a panel-VAR methodology, we examine and evaluate the impact of shocks to the number of startups, idiosyncratic uncertainty, and financial conditions on the investment growth at the industry level. Our findings can be summarized as follows. First, a shock to the number of new firms has significant effects on investment that persist for many years. Second, although all the three variables are important drivers of investment growth dynamics, uncertainty has the largest impact (explaining about the 15% of the variability of investment growth), firm creation follows (it explains about the 7%), while financial conditions have the smallest direct effect (explaining the 3.5%). Finally, we demonstrate that firm entry constitutes an important propagation mechanism for the transmission of uncertainty shocks in the investment growth trajectories.     

Anchoring-Adjusted Capital Asset Pricing Model

What happens when the capital asset pricing model is adjusted for the anchoring and adjustment heuristic of Tversky and Kahneman [1974 Tversky, A., and D. Kahneman. “Judgment Under Uncertainty: Heuristics and Biases.” Science, 185, (1974), pp. 1124–1131.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]]? The surprising finding is that adjusting the capital asset pricing model for anchoring provides a plausible unified framework for understanding almost all of the key asset pricing anomalies. The anomalies captured in the theoretical framework include the well-known size and value effects, high alpha of low beta stocks, accruals, low volatility anomaly, momentum effect, stock splits, and reverse stock splits. The market equity premium is also larger with anchoring. This suggests that the anchoring-adjusted capital asset pricing model may provide the needed unifying structure to behavioral finance.     

A Modified GARCH Model with Spells of Shocks

The GARCH model is modified to capture the effect on volatilities of the consecutive number of positive or negative shocks. The new model is tested against the Shanghai Shcomp and Nikkei225 indices and found particularly useful in analyzing the Shcomp index. Similarly, the EGARCH model is extended along the same line as the GARCH model and is applied to the same sets of data. Stationarity of the new GARCH (1, 1) model is proved, and also derived is the asymptotic distribution of the quasi-maximum likelihood estimator.     

Impact of the federal open market committee's meetings and scheduled macroeconomic news on stock market uncertainty

This study investigates the impact of the scheduled Federal Open Market Committee (FOMC) meetings and the scheduled macroeconomic news releases on stock market uncertainty. For that purpose, the behavior of the implied volatility of the S&P100 index (VIX) is investigated around the FOMC meeting days and around the employment, producer price index (PPI), and consumer price index (CPI) reports. The results support the hypothesis that implied volatility increases prior to the scheduled news and drops after the announcement. The results reveal that investors regard the FOMC meetings as highly significant for valuing stocks as hypothesized. Of the macroeconomic news releases, the employment report has the largest impact on uncertainty, whereas investors regard the information content of the PPI and CPI together as significant.     

Regime shift,speculation, and stock price

We investigate the impacts of speculation on stock price and return volatility in a framework with regime shifting. We find that greater difference in beliefs about the probability of bad state leads to higher stock prices. The intuition is that in periods of higher dispersion of beliefs, the investors perceive greater speculative opportunities, leading to increased demands and valuations of the stock. When investors agree with each other on the state of dividend growth, they have a stronger incentive to invest in the riskless bond, when becoming more pessimistic about the dividend growth. As a result, the demand and the valuations of stock decrease. Moreover, higher level of heterogeneity in beliefs gives rise to higher volatility of the stock returns, even in the absence of dividend shocks. Furthermore, with homogeneous beliefs, return volatility with respect to investors’ beliefs follows an inverted-U shape.     

土性参数的相关距离研究

在自然过程中形成的土,其物理力学性质指标具有自相关的特性,这种特性可用相关距离来衡量。对于岩土工程参数的统计计算应考虑相关距离的影响,这样能更真实、准确的反映地基土的特性。以西安市地铁一、二号线勘察的静力触探数据,根据Vanmarcke提出的土层概率模型、土性相关距离的定义以及方差折减函数Γ(2h)的基本性质,采用递推空间法计算得出各地基土层的相关距离。