信号交叉口延误模型及其在控制策略中的应用

本文主要介绍延误与信号控制参数之间的关系,重点分析了饱和度与延误的关系,并对两者之间的关系曲线进行拟合.引用了延误基本模型,并分析该延误模型在实际中的应用.本文的研究对交叉口信号控制具有一定的实用价值.     

交叉口信号控制与设施优化

从交叉口设施优化和信号控制两方面入手对交叉口交通组织进行分析与阐述。强调在现有交通设施的前提下色彩化、人性化的重要性。同时成功引入博弈论,并在此基础上,以四相位为例建立单点交叉口信号控制模型。     

国省道干线公路非信号控制平面交叉口渠化设计的探讨

本文通过非信号控制平面交叉口影响安全的相关因素进行分析，依照基于运行安全的公路平面交叉口渠化设计指导原则和设计要点,立足于改善平面交叉的道路条件和交通管制条件,合理解决各方向交通流的相互干扰和冲突,以保障交叉口的交通安全和畅通,提高交叉口的通行能力，提出合理化的设计方案，并以具体工程实例说明其可行性,对提高非信号控制平面交叉口的安全水平和通行质量起到了事半功倍的效果。     

哈尔滨市可持续发展系统评价

在建立基于多层次、多指标评价方法的可持续发展系统的状态评价模型的基础上,对哈尔滨市的可持续发展系统各子系统的综合发展水平以及发展的持续度和协调度进行了计算和分析.分析表明:哈尔滨市在1995-2004年各子系统发展水平波动的幅度较大;特别是环境子系统的可持续性发展呈现退化的趋势.     

哈尔滨市土地利用社会经济效益与生态环境效益相关分析

利用哈尔滨市2002—2007年社会经济与生态环境数据,通过建立土地利用综合效益指标体系与权重,计算出哈尔滨市土地利用社会经济效益与生态环境效益指标值。建立三种评价模型,分别计算出社会经济效益与生态环境效益的指标值、协调度、协调发展度以及耦合度值,得出哈尔滨市社会经济效益与生态环境效益相关性良好,整体呈协调发展上升趋势。     

有关等级道路交叉口路线安全设计的研究

随着我国经济增长、人口增加,公路交通事故也在不断增加。等级道路交叉口行人交通安全设计,是等级道路设计的重要工作内容之一。我国不少等级交叉口缺乏行人交通安全设计,是行人交通事故的内在原因之一。本文通过对等级道路交叉口信号控制、渠化设计及交通安全设施等行人交通安全设计方法进行了探讨,为等级道路交通设计工作提出了有益的借鉴。     

基于组合赋权与灰色关联分析的城市创新能力评价研究

文章在分析城市创新系统层次结构和能力构成的基础上,构建了城市创新能力评价指标体系,提出了以AHP与熵权法相结合的组合赋权法和灰色关联分析算法对城市创新能力进行综合评价模型,并进行了实证研究,提出了相关政策建议。     

城市道路平面交叉口渠化设计

道路平面交叉口是城市交通中的瓶颈，而交叉口的渠化设计是提高交叉口通行能力的重要方法。该文针对城市平面交叉口渠化设计特点、原则、基本方法和步骤进行了探讨。并结合余姚市舜水南路新西门路交叉口改造工程进行了案例分析。渠化改造有效地改善了该交叉口交通状况、交通安全和城市景观。     

一种计算群桩基础沉降的影响系数法

在单桩沉降的组成部分分别计算基础上,考虑土承载应力的非线性叠加效应,提出了影响系数计算方法,该法计算方法简便,算例分析表明,计算值与实测值相对于等代墩法能有更好的一致性,验证了本文方法的合理性。     

延误工期的计算

当发生了承包人有权进行索赔的事件后,例如工程师未能在承包人要求的时间内提供工程图纸或承包人遇到了他不能控制的自然条件或人为障碍等情况,如何合理或正确地估价造成延误的事件对工程进度和工期的影响以及索赔时间的长短,是一个十分复杂的问题,而更难判断的是几个事件或更多事件对工程进度和工期的综合影响及其程度。可以说延误工期的计算是工期索赔的难点,也是承包人提出工期索赔是否合理的关键。本文将结合具体的工期索赔实例阐述如何计算延误的工期。     

Forecasting and analyzing the competitive diffusion of mobile cellular broadband and fixed broadband in Taiwan with limited historical data

Taiwan experienced the rapid growth of mobile cellular broadband from 2005 by introducing 3G operations and had higher penetration than the average of the developing countries, the world, and even the developed countries. There are many forecasting models which were developed and successfully predicted the diffusion of long lifecycle product, but there are very few forecasting models which were developed for predicting new products with short lifecycle. Assumption of these models is always the growth of products follows an S-shaped curve. As for the products which were just introduced to the market, it is very difficult to identify if they follow an S-shaped curve with their limited historical data. This research aims to apply Grey system theory to predict the diffusion of mobile cellular broadband and fixed broadband in Taiwan since Grey system theory has a characteristic which requires very limited primitive data (the least 4 data) to build a differential forecasting model. We use penetration as an indicator to describe the diffusion of new products. The numerical data show that the Grey forecasting models GM(1,1) built in this paper have higher prediction accuracy than logistic models and grey Verhulst models. Moreover, we apply Lotka–Volterra model to analyze the competitive relationship between mobile cellular broadband and fixed broadband. The empirical data show that the relationship is commensalism rather than predator–prey. These results can be extended to contribute to other researches.     

Economic/ecological tradeoffs among ecosystem services and biodiversity conservation

An integrated economic/ecological model is built to address tradeoffs between biodiversity conservation and two marketable rangeland ecosystem services: cattle grazing and elk hunting. The ecology is represented by an eleven species food web in which individual optimizing plants and animals engage in competitive and predator/prey relationships. The ecological model defines a steady-state set of sustainable grazing and hunting options, and for each option, biodiversity is measured using an index defined over the eleven species. In linking the ecology to the economics, social welfare depends on grazing profits and hunter net benefits. The problem can be stated as maximizing economic welfare over two ecosystem services, subject to their sustainable use and subject to a target level of biodiversity. A numerical application with economic and biological data from the Western United States is used to determine sustainable grazing and hunting options for alternative biodiversity levels, and to select the option that maximizes welfare.     

Wealth Accounting,Exhaustible Resources and Social Welfare

The empirical literature on natural resource accounting uses methods which implicitly or explicitly entail measuring changes in total resource asset value when an exhaustible resource is depleted. In contrast, the growth theoretic literature on saving, social welfare and sustainable development is built upon a central finding, that the change in real wealth (as measured by net or ‘genuine’ saving) is proportional to the change in social welfare. We show that the change in total wealth exceeds the change in real wealth in optimal and non-optimal models of resource-extracting economies. This suggests that the change in social welfare is over-estimated when the change in total resource asset value is used as the measure of depletion. A simple empirical exercise, using World Bank data on ‘adjusted net saving’, reinforces the results from theory.     

So you want to build a trade model? Available resources and critical choices

This paper reviews recent developments in trade theory, data, and modeling to provide guidance to researchers who are building and using trade models. Our findings show that trade models have fallen behind the latest development in theory, in part because data collection has not (and arguably will not) be able to keep pace with the needs of models built to incorporate the latest theories. The direction, much less the magnitude, of the errors made due to the limitations of today's trade models is uncertain, which should be a grave concern to modelers and the policymakers who rely on these models.     

Empirical research on time-varying characteristics and efficiency of the Chinese economy and monetary policy: evidence from the MI-TVP-VAR model

Based on the general time-varying parameter vector autoregressive model and data mining technology, this study proposes a new extension mixed innovation time-varying parameter stochastic volatility vector autoregressive model and investigates time-varying characteristics and efficiencies of different shock effects on China’s monetary policy towards inflation and GDP. Using sample monthly data for 1979–2014, we utilize typical time points to illustrate the mechanisms between different economic variables via the Markov Chain Monte Carlo method and impulse response function. The empirical results show that the monetary transmission mechanism in China can be effective in the real economy, but with delay and efficiency leakage. The average delay and maximum efficiency can be measured through the MI model, which can capture accurate information of economic variables, effectively improving the precision of macroeconomic regulation and control. Meanwhile, the difference between the impacts of different channels is obvious; while the impact of interest rates is not significant, the impact of stock market is significant. The action mechanism between GDP and the inflation rate undergoes a gradual structural change, evidently displaying time-varying characteristics and a gradually weakening impact over time.     

A multivariate analysis of forecast disagreement: Confronting models of disagreement with survey data

This paper documents multivariate forecast disagreement among professional forecasters and discusses implications for models of heterogeneous expectation formation. Disagreement varies over time and is positively correlated with general (economic) uncertainty. The degree to which individual forecasters disagree with the average forecast tends to persist over time. Models of heterogeneous expectation formation can be modified by introducing heterogeneous signal-to-noise ratios to match this feature. Furthermore, disagreement about correlations of different macroeconomic variables is high on average. In general, multivariate forecast data can be used more effectively than it has been to estimate models with heterogeneous expectations and to test the mechanisms used to generate disagreement in these models.     

The minimum wage and the Lithuanian labour market

This paper presents a comprehensive and non‐standard labour market analysis based on univariate and multivariate models for wages. The novelty of this paper lies in the use of non‐normalized cointegrating vectors for labour market analysis. Wages are the basis of labour market models, as well as the key factor for employees and employers; therefore, the central analytical axis is a classical wage bargaining process, where one side requires and the other side proposes a certain level of wages. Analysis is divided into two parts: foremost, a careful analysis of Lithuanian wages is conducted and a univariate model for the investigation of interactions between the minimum wage and the rest of the wages is proposed; only after the minimum wage model is drafted can the multivarate model for the whole economy be built up. Briefly, the methodology used in this article can be annotated as a synthesis of sequential theoretical and empirical considerations that combine the results of theoretical macroeconomics with data‐generating patterns and stylized facts. The model is considered as the final one only if macro‐theory preconditions, statistical prerequisites, and stylized real‐world requirements are met and fulfilled. In addition, this article gives an example and a quantitatively, as well as qualitatively, motivated suggestion as to how to incorporate minimum wages into econometric models and puts forward an explanation for why it is necessary to include minimum wage dynamics into labour market analysis. The article is nothing but an empirical case study that demonstrates how many minor details have to be taken into account until a realistic labour market model is built up. Although the paper deals with the labour market, the suitable application of time series methods is the main subject of the analysis.     

Of maps and territories : The use and abuse of socioeconomic modeling in support of decision making

While the need for better data and models to support environmental decision making is generally recognized, the need for new approaches to how those data and models are used in the policy-making process has received less attention. Yet the relationship between analysis and policy is often characterized by problems of misunderstanding and mistrust between analysts and decision makers. The purpose of this paper is to examine the role of socioeconomic models in forecasting and decision making about environmental problems, and to suggest ways in which such models can be developed and used so as to increase the chance of their playing not only a scientifically but also a politically useful and desirable role.     

Strategic delay and endogenous offers in bargaining games with private information

This paperendogenously determines the order of offers and the duration of delay in reaching agreement between buyers and sellers in a continuous-time bargaining game in which a seller wishes to vend an object of known cost to a buyer, to whom the value of the good is private information, and in which each player can choose to strategically delay a response to a previous offer or to interrupt the delay of his rival. Both buyers and sellers are shown to prefer to move first in a model of bargaining in which: (1) either player can make the first offer; (2) after the minimum time has elapsed from the previous offer, either player can make an offer; and (3) players can choose to strategically delay and refrain from making an offer after the previous offer. When the buyer moves first, the equilibrium response for the seller is to accept the offer immediately. When the seller moves first the equilibrium is characterized by the seller making all but the last offer, with minimal feasible delay between successive offers. Observable endogenous delay in reaching an agreement in such equilibria approaches zero as the minimal feasible delay between offers approaches zero. This indicates that in noncooperative bargaining models with private information, where players can strategically delay their offers, endogenizing the order in which players make offers removes the ability of informational asymmetries to generate equilibria exhibiting endogenous delay in reaching an agreement.     

A general model for culture and technology

This paper offers a process model in which the interaction of technology and social institutions can be analyzed systematically within a single frame of reference. By considering both aspects of culture, not as substantive entities to be classified as to type, but as organizational states to be described and measured by a class of variables that is truly scaleable, it is possible to describe with precision and economy, a given state of techno-social organization and also design and predict future states of technological and social organization The potentialities and properties of various possible future states can be projected as highly compressed, synoptic models since the number of variables used to describe a real or projected system-state is small. Thus the model offers a versatile instrument for disciplining rich and diverse classes of data into manageable wholes. It also offers possibilities of making normative judgements of what kind of organizational linkages between technology and social institutions will produce relative consistency or effectiveness.