小仰角下移动卫星通信性能的改善及仿真

移动卫星通信系统为功率受限系统,相对地面移动通信而言,其链路余量较小,而且由于多径及遮蔽效应,当系统工作在小仰角时,其信号衰落可达到30dB,这对系统的设计提出了严峻的挑战。本文研究了信道编码和交织技术在移动卫星通信系统中的应用。通过仿真,得到了应用该技术对不同仰角特别是小仰角条件下系统性能的改善程度。同时,在研究信道相关的基础上,给出了交织相关参数的设计准则。     

一种新的OFDM同步跟踪技术及其在VHF/UHF通信系统中的应用

本文主要研究了我国加工贸易领域信息化管理的系统组成和发展状况,通过深入分析加工贸易的业务流程、信息化管理特点、发展困惑等内容,提出了优化加工贸易信息化管理的相关举措。     

数据包络分析有效性理论的一点探索

文章给出经典的基于输入的和基于输出的数据包络分析(DEA)模型,以及把基于输入和基于输出的模型相结合的相对效率模型,并且把这些模型引用到评价证券的相对有效性上,以风险作为输入,期望收益率作为输出,便可以用DEA模型评价每只证券的相对有效性.     

Pricing of Mutual Fund Services in Retirement Plans: Evidence from Open-End Equity Funds

Management fees of mutual funds are more costly to investors than is often realized. Moreover, research indicates that in many cases, the fees are not related to performance, contrary to what might be expected from an efficient market. This study uses sample data to illustrate the consequences of inefficiency to an individual investor. It then turns to an empirical examination of the determinants of the ratio of management fees to total assets (MER), investigating market concentration, fund performance, and non-performance characteristics as explanatory variables. All of these classes of variables contributed to the variation of MERs . JEL Classification G23     

Got milk? The rapid rise of China’s dairy sector and its future prospects

This paper synthesizes recent research and new empirical findings to build a more comprehensive understanding of developments in China’s dairy sector. China’s tremendous rise in dairy demand has been driven by several mutually reinforcing factors: including rapid income growth, promotion by the government and dairy industry, changes in urban lifestyles, and the development of new, more sophisticated marketing channels. Domestic milk output has grown to satisfy rising demand largely by increasing the dairy herd. Substantial increases in productivity have been achieved through technology adoption, but there is evidence that the torrid growth has created inefficiencies because adaptations to marketing rules, infrastructure, and institutions have not kept pace with the changing environment. These results suggest there is ample room for future growth in both domestic milk production and dairy demand, but multinational firms and imported products will likely play and increasing role as China’s dairy market continues to develop.     

Measuring Efficiency: A Comparison of Multilevel Modelling and Data Envelopment Analysis in the Context of Higher Education

Data envelopment analysis (DEA) and multilevel modelling (MLM) are applied to a data set of 54,564 graduates from UK universities in 1993 to assess whether the choice of technique affects the measurement of universities’ performance. A methodology developed by Thanassoulis and Portela (2002; Education Economics, 10(2), pp. 183–207) allows each individual's DEA efficiency score to be decomposed into two components: one attributable to the university at which the student studied and the other attributable to the individual student. From the former component, a measure of each institution's teaching efficiency is derived and compared to the university effects from various multilevel models. The comparisons are made within four broad subjects: pure science, applied science, social science and arts. The results show that the rankings of universities derived from the DEA efficiencies which measure the universities’ own performance (i.e., having excluded the efforts of the individuals) are not strongly correlated with the university rankings derived from the university effects of the multilevel models. The data were also used to perform a university‐level DEA. The university efficiency scores derived from these DEAs are largely unrelated to the scores from the individual‐level DEAs, confirming a result from a smaller data set (Johnes, 2006a; European Journal of Operational Research, forthcoming). However, the university‐level DEAs provide efficiency scores which are generally strongly related to the university effects of the multilevel models.     

失地农民问题与制度变迁

在制度演进论的框架下分析了农民失地的制度变迁过程,重新分析了被我国学者忽视的失地农民和城市居民作为行为主体参与博弈过程所起到的重要作用,提到了要关注制度执行的效率与结果及失地农民补偿后会带来的社会问题。提出加强制度的执行监管,建立一种平衡机制,达到社会和谐的目标。     

多媒体教学在高职高专英语教学中的应用

在高职高专英语教学中运用多媒体可充分调动学生学习的主动性和积极性，培养学生的创新能力，进而优化课堂教学，提高教学效率，有效地解决高职高专英语教学中存在的问题。     

A Critique of the Legal and Philosophical Case for Rent Control

Rent control is an economic abomination. It diverts investments away from residential rent units, it leads to their deterioration, it is responsible for urban decay such as in the South Bronx, it does not help poor tenants, it is a horrendous means of income redistribution. Yet this economic regulation is beloved of intellectuals (hot beds of pro rent control sentiment are Berkeley, Ann Arbor and Cambridge) particularly in the legal and philosophical communities. The present article is dedicated to an exploration and rejection of the arguments in behalf of rent control which emanate from this source.     

关于汉语/英语AMR语音编码参数统计特性的研究

自适应多速率（AMR）算法是第三代移动通信系统中语音业务所采用的语音编码标准。为研究AMR算法应用于汉语语音和英语语音所产生的差异，本文针对ARM语音编码算法的特点，在处理分析了大量汉语语音数据的基础上，对算法中的线谱频率（LSF）、基音周期等关键编码参数进行了比较并给出相应结合。本文的研究有助于AMR算法针对汉语语音的性能优化。