利用ACE值构造QC-LDPC码

为进一步提升中短码长下准循环低密度奇偶校验(Quasi-cyclic Low-density Parity-check,QC-LDPC) 码的纠错性能，提出了一种综合短环数目和环连通性的QC-LDPC码构造方法。首先，采用Golomb规则构造QC-LDPC码，对基矩阵中的部分元素进行替换预处理，初步降低短环数目；其次，采用所提的利用近似环外信息度（Approximate Cycle Extrinsic message degree，ACE）的消环掩模算法来优化QC-LDPC码，使得掩模后的校验矩阵具有较大的ACE平均值，最终完成QC-LDPC码的构造。该构造方法简单、通用性强，在短环数目和连通性间进行了平衡。与只考虑减少短环数目、增大围长等方法相比，该方法构造的QC-LDPC码有更加优异的纠错性能。     

Risk preference heterogeneity in group contests

We analyze the first model of a group contest with players that are heterogeneous in their risk preferences. In our model, individuals’ preferences are represented by a utility function exhibiting a generalized form of constant absolute risk aversion, allowing us to consider any combination of risk-averse, risk-neutral, and risk-loving players. We begin by proving equilibrium existence and uniqueness under both linear and convex investment costs. Then, we explore how the sorting of a compatible set of players by their risk attitudes into competing groups affects aggregate investment. With linear costs, a balanced sorting (i.e., minimizing the variance in risk attitudes across groups) always produces an aggregate investment level that is at least as high as an unbalanced sorting (i.e., maximizing the variance in risk attitudes across groups). Under convex costs, however, identifying which sorting is optimal is more nuanced and depends on preference and cost parameters.     

Farm size and smallholders’ use of intercropping in Northwest China

Intercropping, i.e. the cultivation of crop species mixtures, can potentially reduce pressure on land resources by generating higher yields through exploitation of complementarities between crop species. Although intercropping is practiced on a non-negligible proportion of China’s arable land, little is known about the factors that influence farmers’ decisions to use intercropping. In this study we develop a theoretical framework that distinguishes exogenous factors from endogenous factors in farmers’ activity choices in general and the use of intercropping in particular. We apply this framework in an empirical analysis of socio-economic factors affecting the use of traditional and novel relay intercropping systems, with a special focus on the impact of farm size, using primary data collected among 299 farmers in Gaotai County, northwest China. We find that large farms do no not plant more land with the traditional wheat/maize intercrop as compared to small farms, while land planted with the two novel intercrops is significantly larger on large farms. Availability of machinery has no negative effect on the area under intercropping, and has a significant positive effect on the use of one novel intercrop type. Our results confirm that risk considerations do not play a role in relay intercropping use decisions of Chinese farmers. We conclude that positive yield and natural resource effects of intercropping can still be realized if the ongoing farm scale enlargement policy is combined with a policy promoting novel intercropping types, particularly those types that can make use of already available machinery.     

基于K-S检验与距离相关分析的网络借贷信用评价指标体系构建

网络借贷作为一种新型互联网金融模式,提升了金融资源使用效率,缓解了小企业融资难的困局。构建合理的网络借贷信用评价指标体系,从而对网络借贷的潜在风险及时甄别与预防,对互联网金融健康持续发展意义重大。本文根据K-S检验与距离相关分析相结合,筛选对借款客户违约状态甄别能力强的指标,建立了网络借贷信用评价指标体系,通过P2P网络借贷(peer to peer lending,个人对个人借贷)平台LendingClub交易数据进行实证研究,结果表明:不仅借款金额、借款利率等借款标的特征对借贷者违约具有显著相关性,借款者年龄等个人特征、借款者年收入等财务特征以及借款者违约次数等信用特征均对借贷者违约风险产生显著影响。投资者在出借资金时,往往青睐于已婚、年龄适中、具有一定工作经历、历史违约次数较少的借款人。因此,风险监管部门应构建网络借贷违约风险评估模型,对P2P平台进行风险监测,同时建立关键信息共享机制,融合多源数据,明确审查范围,实现P2P网络借贷行业健康有序发展。     

Accounting for diverse risk attitudes in measures of risk perceptions: A case study of climate change risk for small-scale citrus farmers in Indonesia

Climate change is likely to generate severe impacts on smallholder farmers in developing countries. As key drivers of adaptation, climate risk perceptions are highly heterogeneous, varying both across people and context, and are complex, being defined as behaviour which varies across both impact and likelihood dimensions in non-linear ways. Yet most studies examining risk perceptions are unable to disentangle the role of perceptions regarding impacts from those regarding the likelihood of climate-related events taking place. This paper presents a decomposition and associated analysis of survey-based ‘risk perception’ measures. The decomposition we apply allows independent accounting for perceptions over frequencies and impacts linking to behavioural patterns of risk attitude. The approach presented here draws on a detailed 2017 survey of 500 farmers in rural Indonesia to generate insights into the relationship between risk perceptions and extension services, accessibility of information, and other factors. Results show that risk perceptions are generated from complex interaction between perceived future frequencies and outcomes of climate events and indicate differential impacts of extension services across these perceptions. This paper also presents empirical support for the use of information and communication technology based extension as an efficient extension tool to reach more farmers than in traditional methods.     

Cooperative game with nondeterministic returns

We study a non-traditional cooperative game where returns from coalitions are nondeterministic. The long-standing concept of core can be generalized to reflect players’ contentment with their allocations. It is now imperative to formalize the restrictions, such as those pertaining to information, on allocations. The latter are also at times more conducive to fractional representations. With probabilistic structures added, nondeterministic returns become random variables, utility functions attain risk-attitude connotations, and the timing of players’ allocation resolutions gains significance. Under various conditions for utility functions, we show how various core concepts of the general game can be related to its traditionally defined auxiliaries. These developments help pave the way for our illustrations, within two distinct settings, that players’ increased risk aversion would promote the formation of the grand coalition.     

Credit risk pricing and the rationality of lending decision-making within dual banking systems: A parametric approach

The reduction of non-performing loans, and making correct provisions for them, plays a primary role in the management and minimization of banking credit risk. However, these actions depend primarily upon the cost at which banks may dispose of these bad loans. Hence, this study aims to perceive the price of banks’ credit risk via estimating the shadow price of non-performing loans. We assess and compare the perceived price of the credit risk of Islamic and conventional banks operating in 9 countries from the Middle East and Asia, using a quadratic directional distance function. Following this, we evaluate the impact of different settings of directional vectors on shadow prices by conducting a risk-sensitivity analysis. Applying bootstrap regression, the factors affecting NPLs’ prices are further investigated. The paper concludes that the estimation of the shadow prices of bad loans can provide important elements in favor of credit risk management and, therefore, credit risk mitigation.     

Effects of subject pool culture and institutional environment on corruption: Experimental evidence from Albania

This research uses experimental methods to investigate whether subject pool culture and institutional environment have an effect on participants’ corrupt behavior in the laboratory. While we find that subject pool culture does not affect the overall magnitude of corruption of laboratory participants, it does affect the likelihood of corruption and its distribution. Additionally, we find that the effect on corrupt behavior differs with the framing of the experiment’s instructions. Interestingly, in the context of a weak rule of law and high levels of corruption, loaded negative instructions positively affect corrupt behavior of firms and public officials. Previous research in the context of a country exhibiting a strong rule of law and low levels of corruption finds no framing effects. We also find that increasing the probability of detection significantly reduces corruption as measured by the amount of the bribes offered/accepted and the probability of offering/accepting a bribe. Finally, we find that individual risk preferences negatively affect the level of corrupt behavior.     

对我国商业银行中间业务的定价机制与风险管理的思考

商业银行中间业务经营成本主要有：人力费用成本、物力消耗成本、风险产品承受成本。定价机理应采用经营成本收费制度，建立全成本核算体系。遵循合理、公平、诚信和质价相符的中间业务定价原则，积极加强与客户的沟通与告知；遵循中间业务定价流程，进行客户层次细分和市场定位；运用SWOT分析法，谋求竞争定价与实行差别定价，积极加强与同业的合作，防止恶性竞争；坚持服务性能创新，提高服务附加值含金量；适时对银行员工进行培训，积极让员工参与定价决策；适应开放型定价的趋势和要求，酌情考虑产品的关系定价。与此同时应强化担保承诺类表外业务的信用风险管理，交易类中间业务的市场风险管理，服务类中间业务的操作风险管理，而表外业务的信用风险和市场风险管理是风险管理重点。此外，商业银行开展中间业务还应防范政策风险和法律风险。     

高管政治背景与民营企业综合税负——基于政治关联的非线性影响研究

民营企业通过与政府建立良好的关系获得与国有企业同等待遇,税负是其中重要的一个方面。现有研究从线性的角度分析了政治关联对民营企业税负的影响,实际上,不同政治关联度对税负的影响方向是不同的。以2009-2011年沪深两市A股主板民营上市公司为样本,探讨政治关联是否影响企业税负以及政治关联度的变化对企业综合税负率的影响。研究发现,政治关联有助于降低民营上市公司综合税负率,且政治关联度与综合税负率之间存在倒U型关系。研究还进一步确定了政治关联度的拐点,为政府规制政策的制定提供参考。