利用大数据分析技术的智能化网络故障诊断系统

随着网络技术的快速发展以及各种新网络业务的出现，网络的规模日益扩大和复杂。同时，各种网络服务对于网络可靠性的要求也逐渐提高，这就对网络的维护提出了更高的要求。在这种情况下，传统的网络维护模式逐渐不能适应现代网络发展的需求。针对现代大型网络的故障诊断问题，利用大数据分析技术，设计并完成了一套整体的智能化故障诊断系统。在此系统中，针对不同的故障类型，利用能够获取到的数据类型，针对性地设计了相关的故障诊断模块和算法。系统整体基于开源的数据处理平台构建，具备良好的可扩展性。通过实际案例数据的验证，结果表明此系统具备良好的处理实际网络故障的能力，将大数据分析技术应用于网络故障诊断领域也具备较强的可行性。     

Improving forecasting performance using covariate-dependent copula models

Copulas provide an attractive approach to the construction of multivariate distributions with flexible marginal distributions and different forms of dependences. Of particular importance in many areas is the possibility of forecasting the tail-dependences explicitly. Most of the available approaches are only able to estimate tail-dependences and correlations via nuisance parameters, and cannot be used for either interpretation or forecasting. We propose a general Bayesian approach for modeling and forecasting tail-dependences and correlations as explicit functions of covariates, with the aim of improving the copula forecasting performance. The proposed covariate-dependent copula model also allows for Bayesian variable selection from among the covariates of the marginal models, as well as the copula density. The copulas that we study include the Joe-Clayton copula, the Clayton copula, the Gumbel copula and the Student’s $t$-copula. Posterior inference is carried out using an efficient MCMC simulation method. Our approach is applied to both simulated data and the S&P 100 and S&P 600 stock indices. The forecasting performance of the proposed approach is compared with those of other modeling strategies based on log predictive scores. A value-at-risk evaluation is also performed for the model comparisons.     

Do hedge funds time market tail risk? Evidence from option-implied tail risk

This paper focuses on an unexplored dimension of fund managers’ timing ability: Market-wide tail risk implied by information in options markets. Constructing the option-implied tail risk, we investigate whether hedge fund managers can strategically time the tail risk through adjusting their exposure to changes of it. Using an extensive sample of equity-oriented hedge funds, we find strong evidence of tail risk timing ability of hedge fund managers. Furthermore, tail risk timing ability brings significant economic value to investors. Top-ranked funds outperform bottom-ranked funds by 5–7% annually after adjusting for risk factors. Our results are robust to various robustness checks.     

New development: Fiscal reform in South Korea: looking back and moving forward

ABSTRACT

At first glance, it seems that South Korea’s three fiscal systems (mid-term expenditure framework, top-down budgeting, and performance management) function well. However, each fiscal system operates separately and they are inefficient because they follow past practices. This article explains what the problems are and how to overcome them.     

Audit Firm Attributes and Auditor Litigation Risk

This study examines the association between auditors' litigation risk and audit firm attributes. Using professional liability insurance premiums as a proxy for auditors' litigation risk, we present evidence that the risk is lower in audit firms having: (1) separate non-audit and audit divisions; (2) a higher proportion of partners; and (3) a higher annual growth in number of CPAs employed. Additionally, we find that the risk is higher in audit firms having: (1) operating losses; and (2) high revenue growth. Our results are consistent with the idea that audit firms' financial condition and organizational structure affect their independence/ expertise, and, in turn, their litigation risk. Our results are broadly supportive of the PCAOB's (2015) and US Department of Treasury's (2008) views that investors, audit committees, management, and other regulators could benefit from having access to financial and organizational information about audit firms.     

机器人可以缓解老龄化带来的中国劳动力短缺问题吗

本文基于机器人替代能力的视角,分别从理论和实证角度探讨机器人能否缓解中国人口老龄化带来的劳动力短缺问题.本文提出衡量机器人替代能力的估计方法,使用2000-2015年58个国家的相关数据,将机器人对劳动力的替代能力进行了估计.估计结果表明,目前一台机器人平均每年大约可以替代60000～83000个小时的劳动工作量,工具变量模型和稳健性检验结果也进一步证明了这一结论.最后,通过使用技术创新扩散模型对机器人密度进行预测,结合本文估计出的机器人替代能力,解答了未来中国的机器人能在多大程度上缓解劳动力供给不足压力的问题.实证结果表明,机器人能够弥补的劳动力工作可以部分抵消由人口老龄化带来的劳动力短缺问题,这对更全面地理解中国人口老龄化问题及相关政策调整有十分重要的意义.     

The intertemporal risk-Return relation,investor behavior,and technical trading profits: evidence from the G-7 countries

The intertemporal risk-return relation and investor behavior are both important pricing factors that jointly determine the expected market risk premium. Using the price adjustment process as a control variable, we find that the intertemporal risk-return relation is positive conditional on bad market news, but is non-positive conditional on good market news. This implies that good (bad) market news weakens (strengthens) the positive risk-return relation. The pattern in the distortion of the risk-return relation is consistent with short-term mispricing in which investors overvalue (undervalue) the stock market in reaction to good (bad) market news. We also show that ignoring the price adjustment process in the estimation of the risk-return relation leads to model misspecification and induces an upward (downward) bias in estimates of the relative risk aversion parameter conditional on good (bad) news. Our model of the asymmetric risk-return relation along with the price adjustment process is capable of generating the return dynamics that is attributable to technical trading profits. We suggest that the profitability of technical trading rules is not a violation of market efficiency, but a consequence of trading rules exploiting the asymmetric effect of price changes on the risk-return relation, along with the persistence property of price changes.     

MNC foreign investment and industrial disasters: The moderating role of technological,safety management,and philanthropic capabilities

Research Summary: We investigate how industrial disasters can discourage FDI and how MNCs' technological, safety management, and philanthropic capabilities can moderate these effects. Using two unique panel data sets of entry and expansion of U.S. wholly‐owned manufacturing subsidiaries overseas, we found that industrial disasters are associated with reduced foreign entry of wholly‐owned subsidiaries in the disaster industry, but not for all firms in the host country experiencing the disaster. We also found that MNCs' technological, safety management, and philanthropic capabilities can, in some cases, positively moderate the negative relationships between industrial disasters and the foreign entry and expansion of wholly‐owned subsidiaries. Additionally, three‐way interactions with government stability suggest that technological and safety management capabilities substitute government stability in managing industrial disasters, while philanthropic capability complements government stability. Managerial Summary: How can MNCs' technological, safety management, and philanthropic capabilities overcome the effects of industrial disasters such as chemical spills and explosions in host countries? Our results show that industrial disasters are associated with reduced foreign entry of wholly‐owned subsidiaries in the industry in which the industrial disaster occurs, but not for other firms operating in the country experiencing the disaster. However, an MNC's technological capability can, in general, lower the negative consequences of industrial disasters in both the entry and expansion of its wholly‐owned subsidiaries. Regarding the institutional quality of a host country, the results imply that MNCs should develop philanthropic capability when the government stability of the host country is strong, and develop technological and safety management capabilities when the government stability is weak.     

Auditors' Responses to Workload Imbalance and the Impact on Audit Quality*

Using detailed data for fieldwork hours and audit hours by rank from audit engagements in Korea, we examine whether audits conducted under workload imbalance, proxied by busy‐season audits, impair audit quality, and how auditors adjust staff assignments for busy‐season audits. We generally find that busy‐season audits are associated with lower audit quality, and that audit firms reduce the involvement of senior auditors during busy‐season audits. In addition, the greater the involvement of senior auditors and junior auditors, the lesser the deterioration in audit quality. Finally, although there is no increase in interim audits in response to workload imbalance during busy seasons, increasing interim audits can mitigate the negative impact of busy‐season audits on audit quality. Our results are relevant to auditors and regulators, who have expressed concerns about the adverse effects of workload imbalance on audit quality.     

Does an Audit Judgment Rule Increase or Decrease Auditors' Use of Innovative Audit Procedures?

The current audit environment encourages auditors to conduct defensive auditing procedures in lieu of using new, innovative, and potentially more effective audit procedures, due to concerns these procedures may be second-guessed in litigation or by audit inspectors such as the PCAOB. As a result, auditors may prefer traditional “generally accepted” procedures over innovative procedures that are potentially more effective. We test recent proposals that an Audit Judgment Rule (AJR) encourages the use of innovative, and potentially more effective, audit procedures analogous to the similar Business Judgment Rule that affords legal protections to corporate directors. Under an AJR, litigators or audit inspectors could not second-guess auditor judgments, even if they perceive that alternate judgments would have ordinarily been reached, provided the auditor's judgment was made in good faith and in a rigorous manner. However, the AJR's requirements that auditors must defend the rigor of their innovative judgments could potentially backfire and lead auditors to select more traditional procedures. Under the framework of goal activation theory, we conduct an experiment with audit managers and seniors and find that an AJR makes auditors less likely to select innovative audit procedures, particularly when audit risk is high. They do so despite believing the innovative procedures to be more effective than the traditional procedures. Findings from a supplementary experiment with experienced auditors further suggest that national office affirmation of the reasonableness of the procedures does not help overcome this effect. Overall, our findings suggest that an AJR may have the unintended consequence of further increasing auditors' focus on more traditional, and potentially less effective, audit procedures.