视频流应用层组播系统的设计与实现

文章设计了一个用于视频流分发的应用层组播系统,系统由视频采集、视频编解码、组播传输和服务器4个模块构成。视频捕获采用Video for Windows(VFW)技术实现,编解码基于H.263标准。网络结构上提出使用混合P2P树形结构,降低了中心服务器的压力,服务器负责会议成员信息的管理,为组播树的建立与维护提供支持,组播传输使用基于度约束的构造算法,考虑了节点带宽和计算能力。该系统已投入运行,基本达到设计目标。     

含硫油气井中的硫化氢气体检测和防护应急程序

文章详细分析了含硫油气井勘探开发中硫化氢气体产生的来源、硫化氢的主要检测方法,并重点论述了防护硫化氢的应急管理程序。     

Internal Markets,Management by Targets,and Quasi‐Markets: An Analysis of Health Care Reforms in the English NHS

There have been two major attempts to introduce market mechanisms into England's National Health Service: the ‘internal market’ reform project of the 1990s, and the ‘quasi‐market’ of the 2000s. Despite their similarities, the former attempt was on balance unsuccessful while the latter succeeded. This article examines and compares the outcomes of the two periods, analysing the reasons for their relative successes and failures. It goes on to highlight options for future reforms that would build on those achievements.     

Defining Capitalism

This article aims to incorporate the essential features of capitalism in an operational definition that identifies capitalism per se (pure laissez‐faire capitalism), and clearly excludes variations such as welfare capitalism and crony capitalism. By concisely highlighting the fundamental structures and mechanisms of capitalism, this essential definition facilitates defences of it that are more robust than those ordinarily offered. It also clarifies the relation between capitalism and phenomena with which it is frequently associated, and suggests a straightforward way of identifying and measuring the extent of capitalism in mixed economies.     

Informational cascades with endogenous prices: The role of risk aversion

In this paper, we show that long run market informational inefficiency and informational cascades can easily happen when trades occur at market clearing prices. We consider a sequential trade model where: (i) the investors’ set of actions is discrete; (ii) dealers and investors differ in risk aversion; (iii) investors’ information is bounded. We show that informational cascade occurs as soon as traders’ beliefs do not differ too sharply. Thus, prices cannot fully incorporate the private information dispersed in the economy.     

The Nature of Corruption Deterrence in a Competitive Media Sector

This paper compares the deterrence provided by a competitive media sector towards government induced corruption with that of a media monopoly in a setting where the media might raise both true as well as false allegations of corruption. It finds that competition’s impact on corruption deterrence is not necessarily better than a monopoly but rather hinges on a delicate balance between government’s kickback from corruption and the media’s potential benefit from exposure. While the paper does identify conditions in which a competitive media sector would improve upon the deterrence provided by a monopoly, it also find conditions under which it would do no better than a monopoly and in some situations its strategic response could be even worse especially when it intensifies effort towards justifying false allegations.     

Growth,deficits and uncertainty: Theoretical aspects and empirical evidence from a panel of 27 countries

We examine the relationship between fiscal deficits and per-capita income growth in a panel of 27 European countries, allowing for perceived risks, in terms of fiscal sustainability, associated with additional government spending. Such risks are proxied by the conditional variability of manufacturing production and stock market returns and by the unconditional variability of two survey-based economic-sentiment indicators. To help clarifying how fiscal variables impact on growth and to provide a point of reference for the interpretation of the empirical results a structural growth model is first identified. We find evidence of an asymmetric relationship, in that fiscal deficits give rise to adverse growth effects if they coincide with high uncertainty regarding the prospects of the economy and no significant negative growth effects in the low-uncertainty case.     

Direct versus intermediated finance: An old question and a new answer

We consider a closed economy where a risk neutral bank competes with a competitive bond market. Firms can finance a risky project either by a bank credit or by issuing a bond which is directly sold to risk averse investors who also hold safe deposits at the bank. We show that the bank tends to allocate more capital to lower quality projects but there are some interesting qualifications. If the asymmetric information concerns only the success probability, then we observe adverse selection while if it concerns only the expected return, bad types are driven out of the market.     

Fiscal stabilizations: When do they work and why

This paper studies the determinants and channels through which fiscal contractions influence the dynamics of the debt-to-GDP ratio and GDP growth. Using data from a panel of OECD countries, the paper shows that the success of fiscal adjustments in decreasing the debt-to-GDP ratio depends on the size of the fiscal contraction and less on its composition. The rate of growth of output matters too, but higher GDP growth does not drive the success of a fiscal stabilization. In contrast, whether a fiscal adjustment is expansionary depends largely on the composition of the fiscal maneuvre. In particular, stabilizations implemented by cutting public spending lead to higher GDP growth rates. The effects of the composition on growth work mostly through the labor market rather than through agents’ expectations of future fiscal policy. Finally, the evidence suggests that successful and expansionary fiscal contractions are not the result of accompanying expansionary monetary policy or exchange rate devaluations.     

Dynamic Costs of the Draft

Abstract. We propose a dynamic general‐equilibrium model with human capital accumulation to evaluate the economic consequences of compulsory services (such as military draft or social work). Our analysis identifies a so far ignored dynamic cost arising from distortions in time allocation over the life cycle. We provide conservative estimates for the excess burden that arises when the government relies on forced labor rather than on income taxation to finance public expenditures. Our results suggest that eliminating the draft could produce considerable dynamic gains, both in terms of GDP and lifetime utility.