区域交叉口交通拥堵传播规律挖掘方法研究

为了准确识别和预测区域交叉口的交通状态,研究道路网络中的拥堵传播规律,以交叉口流量数据为研究基础,提出了一种改进型需求-容量的交叉口交通状态判别方法。结合交通领域的具体特点,对算法数据库进行适应性调整,采用一种基于路网拓扑结构约束的Aprior算法,建立区域交叉口拥堵传播规律挖掘模型,并以苏州市某区域的交叉口数据为实例进行验证,从时间维度分析发现拥堵具有相似性和反复性,从空间维度研究获取"回溢"和"流出"2种拥堵传播模式,与现实情况相符。结果表明,模型能够有效挖掘区域交叉口拥堵传播规律,并根据传播规律中各个交叉口拥堵发生的时序特性进行交通状态预测。所得结论对实现拥堵预警和交通拥堵的早期干预具有一定的借鉴意义。     

International Telecom Settlements: Gaming Incentives, Carrier Alliances and Pareto-Superior Reform

Liberalized countries that allow competition in international telecommunications favor traffic re-routing practices as arbitrage against foreign monopolists. This view is seriously incomplete. Monopolists, allied with carriers in liberalized countries, can use these practices to reduce termination payments to nonalliance carriersöthereby harming also consumers in liberalized countriesöby gaming regulations that require equal termination rates at both ends and 'proportional return' (the monopolist's traffic is allocated among carriers in proportion to their shares of traffic to its country). We also present a simple bilateral settlements reform that eliminates gaming incentives and other proportional-return distortions, yet benefits both countries.     

城市公交行业绩效评价体系研究

由于我国城市化的快速发展,城市交通资源的供需矛盾日渐突出,城市交通拥堵问题日益严重,对城市的和谐、可持续发展产生了极大的影响,各城市纷纷提出优先科学发展公共交通的战略,而优先科学发展城市公交首先需要解决的是城市公交行业的绩效管理问题。影响公交绩效的有行业环境和政府资源投入、公交企业和乘客等多种因素,因此,必须要由多个利益相关主体共同参与到公交行业的绩效管理过程中。本文构建了公交行业绩效评价的基本模块。在此基础上,通过模块组合提出了适用于不同层次的公交行业绩效评价组合体系。     

Bill-and-Keep peering

Peering arrangements between Internet Service Providers (ISPs), in which providers agree to carry traffic originating from a peer, are common in the Internet. A common contractual peering agreement between smaller ISPs is “Bill-and-Keep”, where no money changes hands between the peers. This paper first investigates a situation when ISPs who have access to a transit ISP capable of handling their traffic for a fee, decide to peer incurring some fixed peering cost. Using a simple model it is shown that Bill-and-Keep peering is the fair and efficient outcome if the transit ISP charges for both inbound and outbound traffic and transit charges as well as costs of peering are symmetric. Next, complementarity between providers at the operational level, as measured by improvement in quality of service (QoS), is analyzed using an idealized model. Assuming that each provider incurs costs, or degradation in QoS, from its traffic traversing its own as well as the peer's links and chooses the amount of traffic to send on its peers’ links in its self-interest, the Nash equilibria of the resulting one shot game and then of an infinitely repeated game are analyzed. For the one-shot game, it is established that, while it is not possible for all the providers to be worse off, it is certainly possible for all of them to be better off. An intuitive sufficient condition for each of the providers to be better off in Nash equilibrium is then derived. Further, it is shown that providers that are better off in the one-shot game can cooperate using threat strategies in an infinitely repeated game and can each be even better off. Coalition formation between peers as a dynamic process is also investigated and some examples and conjectures on some preliminary findings are provided. Finally, the policy implications of the findings are discussed.     

Is There Room for an Independent Trade Unionism in Russia? Trade Unionism in the Russian Aviation Industry

On the basis of a detailed study of two 'independent' unions, representing pilots and air traffic controllers, this paper argues that there are very limited prospects for independent trade unionism in Russia at present. The air traffic controllers' union has adopted a resolutely independent and militant strategy of pursuing the sectional interests of its members, which has brought it into conflict with management, other unions and the government. The pilots' union, by contrast, has sought to consolidate the position of its members as a labour aristocracy, collaborating closely with management to secure its privileged position. The success of the pilots contrasts starkly with the heavy defeat suffered by the air traffic controllers following their strikes in August and December 1992, indicating the barriers that face the attempt to create trade unions independent of management in Russia.     

复杂耦合网络交通动力学模型研究

为了准确反映网络的交通行为,提出一种基于复杂耦合网络的改进交通动力学模型。对双层结构耦合网络的信息产生和传递情况进行分析,并探讨了复杂耦合网络信息交通过程的特征,引入层间控制参数和层内控制参数分别控制不同层之间信息传递的速度和路径选择,重点考虑了层间传递信息的损耗代价情况。在所提动力学模型的基础上,研究了耦合网络中信息交通过程涌现出的统计学特征。结果表明：提出的耦合网络交通动力学模型中所有节点都能够产生和传递信息,随着层内控制参数的增大,网络交通容量出现先增大后减小的变化趋势,当层内控制参数为3.8时,耦合网络交通容量达到最大。研究结果对交通网络中的拥塞问题的缓解具有指导意义,可以通过调整控制参数来增大网络的交通容量。     

Inconvenience cost of mobile communication failure: The case of South Korea

Mobile communication failure can occur when mobile traffic exceeds the manageable level. This depends on frequency bandwidth. Mobile communication failure causes inconveniences in a user's daily life that lead to social and economic damage. To address this issue, mobile telecommunications companies deploy additional bandwidths and develop new technologies, but these are costly strategies. This study applies a spike model based on a contingent valuation method (CVM) to measure the inconvenience cost resulting from mobile communication failure. The mean monthly willingness-to-pay (WTP) to avoid communication failure per user is estimated to be KRW 898.14 (USD 0.80) over a period of five years in our study. The inconvenience cost borne by the population is estimated to be KRW 2.97 trillion (USD 2.61 billion). Users experiencing greater frequency of communication failure are found to be willing to pay more to avoid the inconvenience. When excluding respondents citing zero-WTP, the mean WTP per user was calculated to be KRW 3426.41 (USD 3.01). Data traffic usage and frequency at which communication failure is experienced are variables that exhibit statistically significant effects on WTP to avoid mobile communication failure. Overall, estimation results show that a price discrimination based on data traffic usage or quality can be considered by mobile telecommunications companies and regulators to address the issue of data traffic inducing mobile communication failure.     

Determination of the research of computer-based technologies for urban traffic systems some experiences in project organisation and management

Research and development activities concerning urban traffic systems are the subject of a long-standing program at the German Federal Ministry of Research and Technology. A fairly recent field of investigation is the deployment of computer-based technologies in urban traffic situations. The German Federal Ministry of Research and Technology has sponsored a study to determine a comprehensive middle-term research-program for these technologies.
The study contained the following steps of investigation:
(1) Determining possible areas of deployment for computer-based technologies.
(2) Selecting deployment areas from those generated.
(3) For the deployment areas selected, deriving the required research activities, coordinating and consolidating them into a research program.
Because of the comprehensive nature of urban traffic the know-how and results from many and diverse scientific disciplines had to be incorporated into the study.
As the study has significant real-life consequences for the direction and funding of urban traffic research by the Federal Ministry of Research and Technology it had to be ensured that its outcomes were operational.
To arrive at an operational research program, the study required inputs from areas, in addition to the scientific disciplines:
(a) politics (traffic policies in general, research and funding strategies etc.)
(b) industries (manufacturers of vehicles, electronic parts etc.) and traffic operating authorities.
Some experiences gained in managing the project are reported in this paper. They pertain to the study described. Hopefully, they can be put to use in some other projects of comparable structure and objectives.     

5G networks: Will technology and policy collide?

Despite being still under development, it is envisaged that 5G networks will provide a ‘fibre-like’ experience to mobile users. As such, they are expected to accommodate services with very different requirements in terms of latency, bandwidth and reliability, among others, for the vertical sectors. However, the European Union has just approved the Telecommunications Single Market Regulation, which enshrines the network neutrality principle and guarantees that ‘all traffic through the Internet is treated equally’. This article explores the potential conflict between net neutrality regulation and future 5G services, particularly regarding network virtualisation. We present a discussion on the challenges of building net neutrality upon judgements on whether traffic optimisation is objectively necessary. This proves complex in a technological environment that envisions network ‘slices’ created and priced on-demand according to the Quality of Service (QoS) required by specific applications at any given time. In addition, we argue that the ‘anything-as-a-service’ paradigm might turn into an important source of innovation for the future Internet infrastructure layer, and thus for the ecosystem as a whole.     

Net neutrality and inflation of traffic

Under strict net neutrality Internet service providers (ISPs) are required to carry data without any differentiation and at no cost to the content provider. We provide a simple framework with a monopoly ISP to evaluate the short-run effects of different net neutrality rules. Content differs in its sensitivity to delay. Content providers can use congestion control techniques to reduce delay for their content, but do not take into account the effect of their decisions on the aggregate volume of traffic. As a result, strict net neutrality often leads to socially inefficient allocation of traffic and traffic inflation. We show that piece-meal departures from net neutrality, such as transmission fees or prioritization based on sensitivity to delay, do not necessarily improve efficiency. However, the ISP implements the efficient allocation when allowed to introduce bandwidth tiering and charge for prioritized delivery.     

基于潮汐交通的可变车道分流带设置研究

为了提高潮汐交通道路的安全度,基于南京市虎踞路调查的交通数据,分析其潮汐交通特性,针对潮汐路段提出优化设计方案,在可变车道内,分析车辆的速度、道路宽度以及汽车转弯半径对分流带长度的影响,利用切函数与约束函数,设计一定长度的自动可移动式分流带。利用交通微观仿真平台vissim对实施协调控制后的结果进行仿真实验,结果表明控制后的车头间距增大,通行效率得到提高,安全度提高。     

基于交通运输方式选择的旅客出行时间价值研究

为了研究旅客出行时间价值与交通方式选择的动态关系,更好地掌握旅客出行方式,在研究国内外关于旅客出行时间价值与交通运输方式选择问题相关文献的基础上,基于旅客角度,阐述了旅客出行时间价值与交通运输方式选择之间的互动关系。以京沪客运通道旅客出行意愿为面向对象,充分考虑旅客的社会经济属性、出行性质属性以及交通运输方式特征属性,通过SP调查研究出行时间价值与交通运输方式选择之间的互动关系,提出了基于消费者效用最大化理论的非集计模型。通过模型推导计算发现:旅客出行方式选择与其经济水平、出行属性密切相关,经济条件和出行属性优越者更倾向于选择快速性与舒适性更好的交通运输方式。研究结果可为交通管理部门科学合理地评估时间价值效益、有效进行交通规划与管理提供参考。     

Characteristics and mobile Internet use intensity of consumers with different types of advanced handsets: An exploratory empirical study of iPhone,Android and other web-enabled mobile users in Germany

This work explores personal characteristics and mobile Internet (MI) use behaviors of consumers equipped with four distinct types of advanced handsets for accessing the Internet via cellular radio infrastructures of mobile network operators (MNO). Furthermore, it investigates the extent to which personal and mobile appliance characteristics explain variance in actual MI use intensity. Data on two demographic variables, three MNO relationship characteristics and actual MI use intensity (average monthly volume of mobile IP traffic generated by a subscriber in May and June 2011) of 9321 adult consumers with a flat MI pricing scheme are extracted from customer files of the German subsidiary of a large international MNO. 959, 2213, 2410 and 3739 of the sample members use an Apple iPhone 3, an Apple iPhone 4, a model running with Google’s Android operating system (OS) and other MI-enabled mobile OS/phone types, respectively. Compared to the adult population in Germany, persons at least 50 years of age are clearly underrepresented among MI adopters with the four studied device types. Differences between the four phone type groups with regard to gender, age, time from enrollment and MI use experience emerge as statistically significant, but they achieve only minor substantial relevance. MI use intensity is highly positively skewed: In each of the four appliance groups, a small number of users disproportionately add to the total MI traffic generated by the subjects. Consumers’ advanced OS/handset type strongly contributes towards explaining MI use intensity variance. iPhone subscribers generate more traffic than Android customers who in turn show a higher MI activity level than individuals running other web-enabled mobile models. Age is the only studied personal characteristic consistently showing a (negative) association with MI usage, which both is statistically and materially significant. Conclusions are drawn for MNO on MI marketing issues. Implications of study limitations for research on MI adoption and use behaviors on the MI are also outlined.     

城市过江通道交通流速度和密度关系研究

为确定城市过江通道交通流特性是否符合经典的速度-密度关系模型,研究了四川泸州市沱江一桥上的过江交通流。利用视频检测技术,获取了包含高峰期、平峰期等各种交通运行状态的交通流流量、速度数据,经过数据清洗、转换后,对速度和密度数据进行了回归分析和显著性检验,并计算得到了交通流特征参数自由流速度和阻塞密度。结果显示,城市过江通道的进城方向更适宜Greenshields的线性关系模型,出城方向更适宜Underwood的指数关系模型。桥头段和桥中段交通流特征参数的差异性,表明了桥头交织段规划、设计与管理对提高过江桥梁衔接段通行能力的重要性,相关部门应合理组织进城方向下游、出城方向上游的交通流,以改善区域交通运行质量。     

Impact of roaming regulation on revenues and prices of mobile operators in the EU

We use a difference-in-differences approach to assess the impact of the EU roaming regulation on mobile operators’ average revenues per user (ARPU) and the retail prices of mobile services. Our results suggest that due to the regulation the ARPU of EU mobile operators decreased since 2007 on average by 9.1%. When considering purchasing power parities, the decline of ARPU is estimated on average at 5.8%, but in this case we cannot reject that there was no decrease at all. We also find that the impact of the regulation on ARPU depends on traffic imbalances, which may be related to tourism flows, and has a stronger negative impact on operators from countries with a surplus in tourism traffic. There is however no difference in the impact of the regulation on cross-country and national operators. Moreover, our results suggest that the Roam Like at Home (RLAH) regulation implemented in June 2017 had no impact on the tariffs of national mobile plans.     

基于可靠度的公路交通安全工程评估与应用分析*

通过对三级道路交通安全工程分析和研究,从自然条件、路线条件、路侧条件等8个方面选取了28项对公路的交通安全影响较大的因素作为评价指标,建立了公路交通安全的评价指标体系。基于安全可靠度充分考虑各个影响因素之间的关系,运用层次分析法和模糊数学理论确定公路交通安全状况的模糊综合评价模型,提出了基于安全可靠度的用于评价公路交通安全的模糊综合评价方法,并结合国道212线甘肃省境内漳县段交通安全状况进行实例分析,结果表明,在安全可靠度满足要求条件下该方法与公路部门的调查具有很好的吻合性,能很好地反映该公路的交通安全状况。     

ICT-enabled system innovations in public services: Experiences from intelligent transport systems

Public transport is confronted with major challenges such as climate change and congestion. This paper discusses how these major challenges are addressed by means of ICT-enabled system innovations in public services. Recent developments in ICT enable the realisation of novel solutions for public transport that can be subsumed under the headline of intelligent transport systems (ITS). However, while the advances in information and communication technology are very fast, the transformation of transport systems and infrastructures tends to take a long time. In parallel, public sector reforms of the past decade, often characterised by the introduction of New Public Management principles, have changed the organisational and institutional conditions for transport service provision and innovation, with the private sector playing an increasingly prominent role. Public–private innovation networks in services (ServPPINs) have been suggested as a concept to foster the realisation of system innovations.This paper analyses the conditions, determinants and instruments for managing ServPPINs successfully, by comparing four cases of ServPPINs in intelligent transport systems, which all aim at establishing system innovations. The four cases are: ITS Vienna Region, a dynamic intermodal traffic information service; compano, a novel ride-sharing scheme in Austria; SIS, a real-time traffic information services, displays and management system in Oslo; and Flexus, an electronic ticket system for public transportation in Oslo.The paper shows the importance of organisational and institutional conditions of ServPPINs for realising these system innovations, and the crucial role of entrepreneurial individuals, both in public and private sector organisations. It also points to the importance of making clear strategic choices at the right moments in time in the course of the life-cycle of ServPPINs.     

A simple game-theoretic analysis of peering and transit contracting among Internet service providers

The paper presents a simple game-theoretic model of two Internet service providers (ISPs), drawn from a larger set consisting of Tiers-1 and -2 ISPs, who choose between peering and transit agreements. The study focuses on the costs of interconnection taking into account traffic imbalances. The analysis suggests that if the traffic flows and the costs of interconnection are fairly shared, the provider's peer, otherwise they choose transit. Moreover, the joint profits are maximized under the transit arrangement.     

时空环境因素对无信号交叉口事故严重程度的异质性影响

为了明确无信号控制交叉口事故的诱发机理、降低事故损失，对美国西南部某州2016年7月至2020年12月的5 956起发生在无信号交叉口的事故数据进行统计分析，构建考虑均值和方差异质性的随机参数Logit模型，并分别针对白昼事故和夜间事故，选取周时间、季节、道路空间因素和环境因素作为影响因素，对模型进行参数估计和边际效应分析。结果表明：夏季对昼夜事故的严重程度有异质性影响；恶劣天气条件仅对夜间事故严重程度存在异质性影响，伴随大雾或者强风的降雨天气是加剧事故严重程度的最主要原因，且影响因素在春、夏季节的交互作用更加复杂；人行横道、交通稳静化措施对轻伤、重伤事故有助于减少人员在事故中的受伤概率；大型交通枢纽以及特殊状态下的路段附近，易发生人员伤亡事故。研究结果可为交通安全改善措施的制定提供参考，为降低道路交通事故风险提供新思路。     

Urban wireless traffic evolution: The role of new devices and the effect of policy

The emergence of new wireless technologies, such as the Internet of Things, allows digitalizing new and diverse urban activities. Thus, wireless traffic grows in volume and complexity, making prediction, investment planning, and regulation increasingly difficult. This article characterizes urban wireless traffic evolution, supporting operators to drive mobile network evolution and policymakers to increase national and local competitiveness. We propose a holistic method that widens previous research scope, including new devices and the effect of policy from multiple government levels. We provide an analytical formulation that combines existing complementary methods on traffic evolution research and diverse data sources. Results for a centric area of Helsinki during 2020–2030 indicate that daily volumes increase, albeit a surprisingly large part of the traffic continues to be generated by smartphones. Machine traffic gains importance, driven by surveillance video cameras and connected cars. While camera traffic is sensitive to law enforcement policies and data regulation, car traffic is less affected by transport electrification policy. High-priority traffic remains small, even under encouraging autonomous vehicle policies. Based on peak hour results, we suggest that 5G small cells might be needed around 2025, albeit the utilization of novel radio technology and additional mid-band spectrum could delay this need until 2029. We argue that mobile network operators inevitably need to cooperate in constructing a single, shared small cell network to mitigate the high deployment costs of massively deploying small cells. We also provide guidance to local and national policymakers for IoT-enabled competitive gains via the mitigation of five bottlenecks. For example, local monopolies for mmWave connectivity should be facilitated on space-limited urban furniture or risk an eventual capacity crunch, slowing down digitalization.