西方空间集聚—扩散理论及北京城区功能的扩散

已被世界上许多国家区域经济发展实践验证的西方空间集聚一扩散理论，是对区域经济发展中带有普遍性特征规律的理论表述。以这一理论为基础，结合北京城区集聚不经济的实际，加快北京城区工业企业、事业单位和与此相伴的住宅、商业用房、交通枢纽、第三产业的择情扩散，保证有效扩散的法律、税制、规划、政府职能、中小城镇、乡镇企业的发展和网络建设等相关环境的建设步伐，是促使北京作为国家首都、世界城市、文化名城、宜居城市功能有效发挥和提升京津冀区域经济合作等级的重要步骤。     

Competition with Congestible Networks

We analyse competition between two network providers when the quality of each network depends negatively on the number of customers connected to that network. With respect to price competition we provide a sufficient condition for the existence of a unique pure strategy Nash equilibrium. Comparative statics show that as the congestion effect gets stronger quantities will decrease and prices increase, under both Bertrand and Cournot competition. In an example with endogenous capacities it turns out that equilibrium capacities are at first increasing and then decreasing in the strength of congestion. Furthermore, capacities are higher under Cournot competition. Welfare comparisons between Bertrand and Cournot competition are unambiguous for fixed capacities, but may turn around for endogenous capacities.     

Two-settlement Systems for Electricity Markets under Network Uncertainty and Market Power

We analyze welfare and distributional properties of a two-settlement system consisting of a spot market over a two-node network and a single energy forward contract. We formulate and analyze several models which simulate joint dispatch of energy and transmission resources coordinated by a system operator. The spot market is subject to network uncertainty, which we model as a random capacity derating of an important transmission line. Using a duopoly model, we show that even for small probabilities of congestion (derating), forward trading may be substantially reduced, and the market power mitigating effect of forward markets (as shown in Allaz and Vila 1993) may be nullified to a great extent. There is a spot transmission charge reflecting transportation costs from location of generation to a designated hub whose price is the underlying for the forward contract. This alleviates some of the incentive problems associated with the forward market in which spot-market trading is residual. We find that the reduction in forward trading is due to the segregation of the markets in the constrained state, and the absence of natural incentives for generators to commit to more aggressive behavior in the spot market (the strategic substitutes effect). In our analysis, we find that the standard assumption of no-arbitrage across forward and spot markets leads to very little contract coverage, even for the case with no congestion. We present an alternative view of the market where limited intertemporal arbitrage enables temporal price discrimination by competing duopolists. In this framework, we assume that all of the demand shows up in the forward market (or that the market is cleared against an accurate forecast of the demand), and the forward price is determined using a market clearing condition.     

TCP/IP拥塞控制研究

综述了Internet上TCP/IP拥塞控制研究方面一些最新的工作,分析了拥塞控制的原理、TCP/IP拥塞控制所使用的典型技术,并着重论述了TCP/IP拥塞控制所面临的问题,包括自相似性问题、效率问题、区分服务等问题,并提出进一步研究的方向。     

Congestion effects in a public-good economy

This paper considers a public-good economy with congestion, where participants jointly produce a public good from input of a private good. This economic model gives rise to a transferable-utility game, the profit game, that depends on consumer preferences and a congestion parameter. The simplicity of the game allows the maximum level of congestion that guarantees the nonemptiness of the core of the economy to be determined. It is known that the sustainability of the Lindahl equilibrium in the core of the economy depends on the distribution of profits. In this paper two distributions of profits are compared: the Lindahl solution and the marginal-contribution solution. The latter is more often in the core than the Lindahl solution which in turn Lorenz-dominates the marginal-contribution solution.     

Auditors' Responses to Workload Imbalance and the Impact on Audit Quality*

Using detailed data for fieldwork hours and audit hours by rank from audit engagements in Korea, we examine whether audits conducted under workload imbalance, proxied by busy‐season audits, impair audit quality, and how auditors adjust staff assignments for busy‐season audits. We generally find that busy‐season audits are associated with lower audit quality, and that audit firms reduce the involvement of senior auditors during busy‐season audits. In addition, the greater the involvement of senior auditors and junior auditors, the lesser the deterioration in audit quality. Finally, although there is no increase in interim audits in response to workload imbalance during busy seasons, increasing interim audits can mitigate the negative impact of busy‐season audits on audit quality. Our results are relevant to auditors and regulators, who have expressed concerns about the adverse effects of workload imbalance on audit quality.     

Impact of electronic road pricing on real estate prices in Singapore

Since 1998, Singapore has had an Electronic Road Pricing (ERP) system set up with a network of toll gantries to tax vehicles entering designated areas in the city center during peak hours. Using the congestion rate hike with effect from November 1, 2010 as an exogenous shock, we test the effects of the ERP rate hike on retail, office and residential real estate prices. The results show that the November 2010 congestion toll rate increases cause a 19% drop in retail real estate prices within the cordon ERP areas relative to retail real estate prices outside the cordon ERP areas. The results are statistically and economically significant. However, the toll rate hike has no significant impact private office and residential real estate within cordoned ERP areas. The robustness and falsification tests could not reject the negative effects associated with the toll rate hike on retail real estate prices.     

上海市交通拥堵成本测算及对策研究

依据美国德克萨斯运输学院交通拥挤外部成本的经典测算模型，将交通运输拥挤成本分为时间延误成本、额外燃油消耗成本、环境污染物排放成本和噪音成本三个方面，对于2015年上海市工作日高峰期交通拥挤的外部成本进行了详细的测算。结果表明，交通拥堵的外部成本约占当年上海市GDP的0.63%。最后，对于交通拥堵成本较高的现状提出了包括对上海市部分高度拥堵路段或区域收取拥堵费、大力发展上海市公共交通和发展交通快慢型出行方式共存在内的相关政策和建议。     

‘Swift Rail’—funding local rail transit through smarter growth

Many medium-size cities suffer from severe traffic congestion and poor accessibility, limiting their potential to improve their economy, environment, and social equity. These problems could be addressed by creating high-quality transit linking such cities with suburban and other catchment areas through use of existing rail lines and abandoned former railway alignments. This concept, termed ‘Swift Rail’, would call for an innovative approach to local railway and transport development.     

一种基于单片机的智能充电系统设计

文章以ATmega8单片机为核心搭建智能充电系统,基本消除了镍镉电池的记忆效应,使充电参数调整自动化。在完成快速充电过程后自动转换为涓流充电模式,使充电过程按理想的充电曲线进行,达到了既保护电池又使电池充满的最佳效果。该充电系统有效地解决了普通充电器易将电池充坏的问题,大幅度提高了充电电池的使用寿命。