基于ARIMA模型的海南旅游者人数预测

根据历年海南接待旅游者人数相关数据,分析海南接待旅游者人数的长期趋势、季节性和随机扰动等特征,应用SPSS软件,建立ARIMA时间序列模型,对海南旅游者人数进行预测。     

中国产学研三大部门技术创新经费投入产出效率评估研究

高校、科研单位与企业三大部门是我国应用研究和试验发展环节的重要技术创新主体，亟需评估其效率。采用“经费支出—专利产出—预期收益—实现收益”三步骤分析框架，利用已有统计调查数据，对三大部门技术创新经费投入产出效率进行测算。结果表明，三大部门技术创新经费投入产出效率都偏低，企业部门每亿元经费投入实现的收益约为9733万元，科研单位约为1331万元，高校约为1166万元。该测算值是真实产出价值的下限，但真实产出不会高太多。产出效率低的主要原因在于，高校和科研单位技术创新的产业应用目标指向性不明确、存在科技成果转化难题以及企业能力制约等。最后，建议加快政府相关科技计划制定、加强成果评价过程中产业部门的参与、优化高校和科研单位科研评价体系、加大企业研发费用加计扣除力度等。     

Does the mixed-ownership reform improve the productivity of state-owned enterprises? Evidence from companies listed in Chinese stock

The Chinese government initiated a new round of state-owned enterprise (SOE) reform in 2015 to improve SOE's performance with a focus on introducing multiple ownership shareholders and strategic partners, known as the mixed-ownership reform (MOR). This paper examines the policy effectiveness of the current MOR, an ongoing quasi-experiment, for listed SOEs’ productivity from 2011 to 2019 using a time-varying difference-in-difference (DID) approach. Overall, the total factor productivity (TFP) of SOEs selected as pilots by the government improved significantly by 14.57% after the reform compared to other SOEs, providing evidence for the positive role of the current MOR. This positive impact is prolonged and tends to increase in the post-reform years. A series of robustness checks show that our empirical specification satisfies the basic assumptions of DID and our findings are robust. By comparing the two reform strategies in the MOR, we find that the restructuring and reorganization plan is the primary channel driving TFP growth, showing a 0.4% improvement after the reform, rather than the employee stock ownership plan. We also investigate the impact of MOR on other financial and non-financial indicators, but we only find a significant increase in the profitability of SOEs’ assets.     

技术创新、产业结构升级对能源消费的影响研究——以长三角地区为例北大核心

技术创新和产业结构升级是长三角地区优化能源消费、提高资源利用效率的关键。本文在分析技术创新、产业结构升级对能源消费的作用机制的基础上,运用长三角地区2000~2020年的面板数据构建面板向量自回归模型(PVAR)进行实证分析研究。研究结果表明,技术创新和产业结构升级短期内会造成能源消费的增加,而在长期对能源消费均表现出显著的抑制作用;技术创新、产业结构调整对能源消费的影响程度是逐步增强的,而能源消费自身的惯性作用则不断减弱;在长期中,产业结构升级和能源消费自身对能源消费的变动影响最大,技术创新影响相对较小。     

LDPC码的一种高效加权比特翻转译码算法

针对低密度奇偶校验(LDPC)码中加权比特翻转(WBF)译码算法在迭代过程中绝大多数情况都是进行单比特翻转，导致译码效率低并且可能会发生比特翻转“死循环”的现象，提出一种更为高效的加权比特翻转(EWBF)算法。该算法对翻转阈值进行了改进，使得每次迭代能够翻转多个比特，提高译码效率，并且能够避免译码过程出现的翻转“死循环”现象。仿真结果表明，所提译码算法与WBF算法、改进的WBF（MWBF）算法和IMWBF（Improved MWBF）算法相比，平均迭代次数分别降低51.6%~56.2%、49.6%~54.2%和48.1%~51.3%；而在译码性能方面，算法性能接近甚至优于IMWBF算法，当最大迭代次数设定为30次时，相比于IMWBF算法，在误码率为10－4时可获得0.92 dB 的增益。     

酒店实习效果影响因素的逐步回归分析

采用问卷调查法研究酒店实习效果影响因素。结果表明,酒店实习总体效果影响因素包括酒店的实习培训、实习指导,学校的实习培训、实习指导、实习计划,学生的专业基础、实习态度、实习期望以及实习前准备等因素。知识提高的影响因素包括酒店对学生的实习培训、实习指导,学校的实习培训、实习指导和学生实习前准备等因素。能力提高的影响因素包括酒店的实习培训、实习指导,学校的实习培训、实习指导等因素。     

Examining the carbon emission impact of livelihood transitions in pro-poor tourism

This study examines carbon dioxide (CO₂) emission changes from livelihood transitions during tourism development to assess the environmental impact of pro-poor tourism (PPT) in China. The results indicate that livelihood transitions during PPT increased household income but also produced more CO₂ emissions. CO₂ emissions vary depending on factors including livelihood types after transition, income and household sizes, etc. The CO₂ per unit of income from tourism-based livelihoods is higher than from non-tourism-based livelihoods. Different livelihood strategies post transition also affect emissions. Practical suggestions that may mitigate emissions while not compromising residents’ income levels are provided.