NFC协议的模糊测试优化方案

针对NFC协议进行模糊测试方案时产生大量不符合协议规范的无效测试用例而导致测试效率较低的问题,应用图论思想,提出了基于生成的策略与深度优先算法融合后的模糊测试方案。在基于生成的策略下构造测试用例的过程中,遍历由协议规范连接成的测试需求图,以深度优先算法搜索图中覆盖点较多的生成路径,精简测试用例的生成路径,保证生成的测试用例能够接近协议规范。实验分析表明,所提出的模糊测试方案能够有效地减少无效测试用例的生成,提高测试效率。     

干旱影响生计脆弱性中的中介和调节效应

［目的］气候变化下跨尺度变量对生计脆弱性的影响多数为定性研究,很少进行实证研究,文章通过实证分析探索跨尺度变量在干旱影响生计脆弱性中的作用。［方法］基于黄土高原218个农户调查数据,采用线性回归和层次回归分析跨尺度变量在干旱影响生计脆弱性中的中介和调节效应。［结果］干旱对农户生计脆弱性有显著影响。在干旱影响生计脆弱性的过程中,个人尺度的“户主年龄、感知的气温最大值、降雨量变化、干旱程度变化和灾后信息渠道”与农户尺度的“批发市场距离和集市距离”起到了调节作用; 农户尺度的“三代直系亲属的户数和生产机械指数”起到了中介作用; 而村庄尺度的“工程措施”,既没起到中介作用,也没起到调节作用。［结论］用中介和调节效应反映了跨尺度变量的交互作用,在跨尺度效应的实证研究方面提供了科学的方法,弥补了现有研究的空白,这为制定减少农户生计脆弱性的政策提供了科学有效的依据。     

辽河三角洲湿地景观格局脆弱性变化

目前湿地开发利用日益加剧,本文结合全局自相关、局部自相关进行空间关联分析的研究方法进行分析。虽然辽河三角洲区域脆弱度逐渐减弱,仍有部分地区存在高脆弱度值。数据表明2015年低脆弱度区基本覆盖整个辽河三角洲区域。     

Climate risk,vulnerability and resilience: Supporting livelihood of smallholders in semiarid India

Using panel data from 256 smallholder households from 2006 to 2014 in three semiarid regions India, this study develops a framework for quantifying vulnerability and resilience by accounting for a smallholder household’s ability to adapt and respond to climatic risk. Findings indicate that although smallholders with smaller landholdings are more vulnerable to climatic risk (drought, in our case), they are also more resilient than their counterparts. Results reveal that cropping intensity and crop risk increase the vulnerability of smallholders to climatic risk, but large farms are less vulnerable. Diversification in on-farm enterprises, like livestock units, and off-farm income sources, play significant roles in increasing smallholder households’ resilience to climatic risk. Other drivers of resiliency include the choice of cash and risky crops, borrowing capacity, liquid investments, and the ability to regain yields.     

旅游经济依赖背景下区域经济脆弱性评价研究——以张家界市、阿坝州、丽江市为例

将“过度依赖旅游业”作为导致经济脆弱性的主要诱因,构建旅游经济依赖型目的地经济脆弱性评价指标体系,利用熵值法确定指标权重,进而运用S/R模型和障碍度模型评价脆弱性值并确定主要影响因素。结果表明：张家界市、阿坝州、丽江市的经济发展长期处于极端脆弱或很脆弱状态,投资和出口对经济发展的带动不足、过度依赖旅游业、旅游发展与经济发展水平不匹配、旅游繁荣导致的去工业化和去农业化是经济脆弱性高的主要原因。     

ON THE CONCAVITY AND QUASICONCAVITY PROPERTIES OF UTILITY FUNCTIONS

Concavity and quasiconcavity have always been important properties in financial economics particularly in decision problems when an objective function has to be maximized over a convex set. Both properties have mainly been used as purely technical assumptions. In this paper, we link concavity and quasiconcavity of a utility function to the basic concepts of risk aversion, prudence, risk vulnerability and temperance. We show that concavity means the agent is more risk vulnerable than prudent. In particular, we can see when a function is both concave and quasiconcave and when it is only quasiconcave.     

A composite indicator model to assess natural disaster risks in industry on a spatial level

In the event of natural disasters, industrial production sites can be affected by both direct physical damage and indirect damage. The indirect damage, which often exceeds the direct ones in value, mainly arises from business interruptions resulting from the impairment of information and material flows as well as from domino effects in interlaced supply chains. The importance of industry for society and the domino effects often result in severe economic, social, and environmental consequences of industrial disasters making industrial risk management an important task for risk managers at the administrative level (e.g. civil protection authorities). Since the possible industrial disaster damage depends not only on hazard and exposure but also on the vulnerability of a system, an effective and efficient industrial risk management requires information about the system’s regionalized vulnerability. This paper presents a new methodology for structural industrial vulnerability assessment based on production factors that enables to assess the regional industrial disaster vulnerability. In order to capture industry-specific vulnerability factors and to account for the processes underlying regional industrial vulnerability, a two-stage approach is developed. This approach combines a composite indicator model to assess sector-specific vulnerability indices (V_s) with a new regionalization method. The composite indicator model is based on methodologies from the field of multicriteria decision analysis (MultiAttribute Value Theory) and the Decision-Making Trial and Evaluation Laboratory Method is applied to correct the (V_s) for interdependencies among the indicators. Finally, the developed approach is applied to an exemplar case study and the industrial vulnerability of 44 administrative districts in the German federal state of Baden-Wuerttemberg is assessed.     

“海上丝绸之路”沿线国家地缘脆弱性时空演变及影响因素分析

"海上丝绸之路"倡议将对世界政治经济格局产生深远影响,其推进势必伴随着中国权力半径的延伸和承受沿线国家地缘政治风险的阻碍,沿线国家地缘脆弱性成为影响倡议顺利推进的关键前提。从脆弱性视角出发,界定地缘脆弱性内涵,以敏感性—应对能力作为地缘脆弱性评估框架,基于综合指数法、空间探索性方法和ArcGIS可视化手段,利用GDELT中海量事件数据和沿线国家统计数据,测度2000-2017年"海上丝路"沿线海洋国家地缘脆弱性时空演变特征,探索地缘脆弱性演变的影响因素和内在机制。结果表明:①时间序列上,沿线区域地缘脆弱性波幅较大,不同板块差异显著;空间演变上,脆弱性高的国家数量先升后降,空间格局基本保持稳定。②三项指数均存在集聚性和区域差异性,且体现出地缘政治风险高和地缘影响力大的区域在空间上重叠的"悖论"。③地缘脆弱性演变的影响因素为地缘政治风险和地缘影响力;内在驱动力涉及地缘区位、地缘政治和地缘经济。     

Leading indicators of fiscal distress: evidence from extreme bounds analysis

Early warning systems (EWSs) are widely used to assess a country’s vulnerability to fiscal distress. A fiscal distress episode is identified as a period when government experiences extreme funding difficulties. Most EWSs employ a specific set of only fiscal leading indicators predetermined by the researchers, which casts doubt on their robustness. We revisit this issue using extreme bounds analysis, which allows identifying robust leading indicators of fiscal distress from a large set. A robust leading indicator’s effect does not strongly depend on the model specification. Consistent with the theoretical predictions of latest generation crisis models, we find that both fiscal and non-fiscal leading indicators are robust. In addition, we find that a fiscal vulnerability indicator based on fiscal and non-fiscal leading indicators offers a 29% gain in predictive power compared to a traditional one based only on fiscal leading indicators. This suggests that both fiscal and non-fiscal leading indicators should be taken into account when assessing country’s vulnerability to fiscal distress.