面向卫星导航信号的外辐射源雷达软件化模拟器设计

面向全球导航卫星系统(Global Navigation Satellite System,GNSS)信号的外辐射源雷达,是一种利用环境中GNSS信号作为非合作照射源进行探测的雷达。为满足基于GNSS信号的外辐射源雷达系统仿真和信号处理算法设计评估的需要,通过对该雷达系统组成与工作原理的分析,完成了面向GNSS信号的外辐射源雷达软件化信号模拟器的设计与实现。给定仿真场景下软件化模拟器输出信号处理和分析的结果验证了该模拟器可根据输入参数与模型正确完成信号仿真。     

多波束移动卫星系统的自适应开环预编码方法

对于卫星移动通信系统,由于卫星与地面终端之间的相对运动以及星地间传输延迟,传统的基于理想信道信息的预编码方法是不适用的。针对这一问题,提出了一种基于开环信道估计的预编码方法。卫星端利用开环获取的部分信道信息实现多波束联合预编码,并导出了系统传输速率的闭合解析表达式。此外,为了克服强干扰环境下多波束预编码系统性能恶化问题,提出了一种自适应预编码传输方法。卫星发射机依据开环获得的慢时变用户位置信道信息和信道统计量信息,自适应地选择预编码方法或传统频率复用方法,实现最优的系统性能。理论分析和仿真结果表明,与传统的干扰抑制方法相比,所提方法能实现更优的系统性能,同时也克服了传统预编码方法的局限性。     

Changing patterns of transfers in Slovenia in the last three decades: transition from a socialist economy to a market economy

Rapid population ageing increases interest in economic flows across ages and intergenerational transfers in general. This article uses the National Transfer Accounts methodology to measure consumption and production at each age, and how the difference between consumption and production is financed through (private and public) transfers and the interaction with assets, i.e. ‘asset-based reallocations’. During working ages, people earn more than they consume and with the surplus they finance the deficit of the young and old generations who consume more than they produce. Such a pattern of economic dependency is universal across countries and across time, but huge differences exist in the ages at which individuals produce more than they consume and vice versa. Moreover, the importance of private and public transfers and asset-based reallocations varies across countries and times. In the last three decades, life expectancy at birth in Slovenia increased by 9.3 years, while the age span in which production exceeds consumption narrowed rather than increased. Child dependents are predominantly financed by private transfers, whereas the elderly mainly rely on public transfers. Young and old individuals increasingly rely on public transfers. Together with rapid population ageing, this is likely to jeopardise the public finance system in the future.     

采用COTS器件的低轨星载收发信机设计与实现

在性能、成本和可靠性的多重约束下，采用商用货架（Commercial Off-The-Shelf,COTS）器件设计了一种高性能、低成本星载收发信机。该收发信机的硬件设计不但可同时满足星地和星间应用需要，而且还具有支持多波束、多信道接入的特点。软件设计主要解决了大多普勒频偏条件下的低信噪比解调和变长以太网数据帧的高效处理等问题。地面测试结果表明，在250 kb/s ~ 14 Mb/s信息速率范围内，误比特率低于1.0×10-6时所需的解调信噪比(Eb/N0)不超过2.8 dB，发射信号误差矢量幅度不超过1.9%，高速应用时处理时延可低至3.0 ms。为降低COTS收发信机的可靠性风险，分别在元器件、电路和系统层面进行了有针对性的可靠性保证措施。该设计经过了在轨测试的验证，对其他低轨商业通信载荷的研制有一定的参考价值。     

Forecasts in times of crises

Financial crises pose unique challenges for forecast accuracy. Using the IMF’s Monitoring of Fund Arrangements (MONA) database, we conduct the most comprehensive evaluation of IMF forecasts to date for countries in times of crises. We examine 29 macroeconomic variables in terms of bias, efficiency, and information content to find that IMF forecasts add substantial informational value, as they consistently outperform naive forecast approaches. However, we also document that there is room for improvement: two-thirds of the key macroeconomic variables that we examine are forecast inefficiently, and six variables (growth of nominal GDP, public investment, private investment, the current account, net transfers, and government expenditures) exhibit significant forecast biases. The forecasts for low-income countries are the main drivers of forecast biases and inefficiency, perhaps reflecting larger shocks and lower data quality. When we decompose the forecast errors into their sources, we find that forecast errors for private consumption growth are the key contributor to GDP growth forecast errors. Similarly, forecast errors for non-interest expenditure growth and tax revenue growth are crucial determinants of the forecast errors in the growth of fiscal budgets. Forecast errors for balance of payments growth are influenced significantly by forecast errors in goods import growth. The results highlight which macroeconomic aggregates require further attention in future forecast models for countries in crises.     

New accounts: Towards a reframing of social accounting

This paper is a speculative and exploratory essay on the emerging field of social accounting. In essence, the paper explores whether the fact that most social accounting has, traditionally at any rate, being promulgated by accountants might be a partial explanation for its self-disciplining limitations and, arguably, its weak inroads into discourse and practice. Through the lens of Erik Olin Wright's work, the paper reconsiders the potential of the social accounting project(s) and argues for the importance of accounts as a means of interstitial transformation as a complement to the traditional privileging of accounts directed towards symbiotic transformations.     

“北斗”救生终端海上自适应功率退避算法

受海况、浸水、结冰、对星等因素影响，飞行员海上遇险后报位可靠性较低，工作时长较短。为此，提出一种自适应功率退避方法，在对报位影响因素分析基础上，利用深度神经网络，通过对经纬度、高度、俯仰角、方向、加速度、速度、浸水、信号、电量等多维度数据进行学习，拟合出覆冰、浪涌、液面等信号特征与环境特征联想模型，自适应控制信号发射时机，实现功耗的有效控制。试验表明，该方法将通信成功率及工作时长分别由36.3%、6.0 h提升至73.3%、8.6 h。     

“后农业税时代”村级财务管理创新研究——以浙江农村为例

本文以农户调查资料为依据,对浙江村级财务管理现状进行了实证分析。结果发现,浙江省村级财务管理工作整体水平较高,但同时也在不同程度上存在低层次管理问题。根据调查分析结果,提出了建立与“后农业税时代”相适应的村级财务管理分类运行机制,引入村集体资产经营的“村经理”制度,建立健全村集体报告制度,引入注册会计师业务进农村等一系列村级财务管理创新的对策和建议。     

周跳探测法在北斗精度定位中的应用研究

介绍了北斗卫星导航系统的发展现状以及北斗卫星的组成,运用载波相位测量卫星信号,得出卫星观测过程中存在卫星周跳现象。在此之后,解析了该卫星导航精度定位的误差来源,一共能够分成三种不同的类型,分别指的是：与该卫星自身有关联的误差;与其信号传播路径有关联的误差;与接收机以及测站有关联的误差。在此步骤结束之后,剖析了周跳的定义与特性,除此之外也分析了周跳对精密定位带来的影响。最终,通过仿真方法得到了有无周跳状况下的高次差法的影响。     

Regional Accounts of India: Methods,New Estimates,and Their Uses

For large economies with substantial regional variation, it is of great importance for policymakers and economic analysis that macro‐economic statistics are broken down by region. This paper reviews the regional accounts in India, discusses their role in Indian federal and state policies, and provides new estimates to cover major data gaps. Statistics on domestic product by Indian state, broken down by industry, are regularly published. But despite demands and recommendations by various commissions and policymakers, a comprehensive system of regional accounts is yet to be developed. New estimates for the period 1993–2010 are presented for saving and the macro‐economic expenditure by Indian states, like final consumption, capital formation, and trade balance. They show, for example, that some of the fastest growing Indian states have increased their saving and investment rates to 50 percent of their domestic product.