LT码新型度分布及其在电力线通信中的应用

Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC)，可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布，首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例，获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后，根据IBED在冗余度较小时译码成功率高，而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点，通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合，提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明，与其他方法及传统的RSD相比，采用新度分布进行LT编码，可明显降低译码开销，并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中，能有效地抑制PLC信道中各种噪声对电信号的干扰，并提高通信效率。     

Why will Trump lose the trade war?

ABSTRACT

The escalating U.S.–China trade conflicts have increasingly shadowed the outlook of the world economy. The Trump administration aims to achieve its strategic goals including reducing current account deficits, promoting the U.S. manufacturing sector, and curbing Chinese high-tech industries by waging the trade war against China. This paper argues that the current account deficits and the declining manufacturing sector in the U.S. are mainly driven by its internal structural factors, such as low saving rates, high labor costs, and rising service sector, rather than by the import competition from China. Moreover, the trade war further deteriorates the U.S. current account deficits and erode its comparative advantage, and it forces China to invest more in technological innovation and human capital, and thus promote its progress in high-tech industries. Thus, the U.S. will not be able to achieve its strategical goals and eventually lose the trade war.     

Internal labour markets in the Australian banking industry: their nature prior to the Second World War and their recent decline

This paper uses evidence from late nineteenth-and early twentieth-century personnel records of two Australian banks to examine the nature of internal labour markets prior to the Second World War. It is argued that the industry possessed all the classic features of internal labour markets: limited ports of entry, internal promotion, long careers, and assignment of wages by well-defined rules. The paper then examines the reasons why banks adopted internal labour markets. Finally, the paper examines the recent decline of internal labour markets and examines the role of technological and social changes in this decline.     

技术性贸易壁垒与合格评定程序

随着WTO和贸易自由化的发展，各国的关税水平大幅度降低，以及配额、许可证等非关税措施的逐步取消，大大促进了国际贸易的发展，技术贸易措施在国际贸易中的地位日益重要。合格评定程序是指任何直接或间接用以确定产品是否满足技术法规或标准要求的程序。合格评定程序是企业扩大对外出口、突破技术贸易壁垒的有效措施。     

中国大中型造纸企业技术创新机制探讨

建立和健全大中型企业以技术创新为核心的技术进步的内在机制 ,保障提高技术创新的绩效是目前亟待解决的问题。本文根据 2 0 0 0年中国科技统计年鉴中的数据 ,对大中型造纸企业在技术创新方面存在的主要问题进行分析 ,就如何完善其动力机制和运行机制提出建议     

The persistence of knowledge‐based advantage: an empirical test for product performance and technological knowledge

Resource‐based theory maintains that intrinsic characteristics of resources and capabilities, such as their tacitness, complexity, and specificity, prevent imitation and thereby prolong exceptional performance. There is little direct evidence to verify these claims, yet a substantial literature encourages firms to formulate competitive strategies around resources with these attributes. Further, work outside the resource‐based tradition suggests that these attributes can slow innovation, and it is not clear when this effect outweighs the benefits of inimitability. This paper seeks to clarify whether and how the complexity, tacitness, and specificity of a firm's knowledge affect the persistence of its performance advantages. We find that the complexity and tacitness of technological knowledge are useful for defending a firm's major product improvements from imitation, but not for protecting its minor improvements. The design specificity of technological knowledge delayed imitation of minor improvements in this study. Copyright © 2002 John Wiley & Sons, Ltd.     

关于新贸易理论与制度创新的思考

新贸易理论是在假定各国的市场制度基本健全的前提下，从市场运行的角度考察国际经济和贸易，所以造成其解释力有一定的缺乏；而制度创新理论可能对新贸易理论给出一些互补性思路。     

民营科技企业的产权类型及管理特点分析

民营科技型企业是民营经济的重要组成部分。从产权形式上看,有四种主要类型:创业人员以技术入股带动的私营科技企业;家族式科技企业;股份合作制和职工持股制科技企业;有限责任科技企业。文章就上述类型民营科技企业的产权形式及管理特点进行了分述。     

Static and dynamic efficiency of pollution control strategies

A great deal of the economic literature on pollution control strategies concentrates on the efficiency of environmental policy instruments. Most analytical studies in this field show that market instruments are more efficient with respect to the cost of pollution abatement of a given number of polluters than non-market instruments. According to several analytical studies, market instruments should also be more efficient with respect to innovation in pollution abatement equipment than non-market instruments. In the empirical literature a great number of case studies exist with estimations of the savings of abatement costs of market instruments in a situation without technological progress. Empirical studies about the impact of environmental policy market instruments on the abatement costs in situations with technological progress are lacking.The purpose of this paper is to fill this gap. The paper deals with an empirical estimation of abatement costs for the emission of SO₂ of coal-fired electricity units in the Netherlands from 1985 to 2000. First, the working of market instruments and non-market instruments (the existing environmental policy of the Dutch government) is simulated in a static situation. Second, we analyse the learning effects of flue gas desulphurization. The efficiency advantage of market instruments turns out to be larger in a situation of technological progress than in a static situation.     

提高我国自主创新能力的思考

本文依据当代经济发达国家经济社会发展经验的总结,并从我国当前全面建设小康社会的客观需要出发,分析了提高自主创新能力在国家经济社会发展战略中的核心地位,提出构建体制基础和科技基础以及营造生态环境,是推行自主创新战略的基本措施。