Socio-demographic and built environment influences on the odds of being overweight or obese: The Atlanta experience

This paper explores the association of socio-demographic and built environment characteristics on the odds of being overweight and obese using data from the Atlanta SMARTRAQ travel survey. A new methodological framework based on a multinomial logit (MNL) model and an enhanced odds ratio plot is presented. The use of an MNL model overcomes limitations of many prior studies that employ a sequence of binary logit models to examine multiple weight categories. The use of an enhanced odds ratio plot provides important information into the relative importance of socio-demographic and built environment characteristics. Several new findings for the Atlanta area result from this study. Socio-demographic variables, including age and educational attainment, exhibit a non-linear relationship with the odds of being overweight or obese. Gender, age, ethnicity, and educational attainment are strongly associated with the odds of being overweight or obese, while income and number of students between 5 and 16 years old in the household have smaller effects. Built environment characteristics such as increased net residential densities and enhanced street connectivity are associated with reductions in the odds of being overweight and/or obese. Relative to socio-demographic variables, however, such built environment characteristics have a much smaller impact on describing the odds of being overweight or obese.     

Net tax incidence for urban public transit subsidies in New Zealand

This paper examines the impact of policy changes in the funding of New Zealand public transit modes.These changes, introduced in 1983, are evaluated in terms of the net incidence of public transit subsidy assistance, taking into account its source of funding and the income class of those commuters benefiting from the subsidy. The general conclusion is that the net incidence of subsidy assistance remains progressive (i.e., a transfer from high to low income commuters) following the introduction of shared funding on the predominant public transit modes (rail and bus), sourced from income tax (central government) and property tax (regional/local government). However, because of the predominance of medium to high income commuters on rail vis-a-vis bus and the traditional source of funding on these modes in terms of income tax (a progressive tax source) and property tax (a regressive tax source), the degree of progressivity previously associated with public transit subsidies has now substantially reduced.The analysis and opinions expressed in this paper are the responsibility of the author alone and do not purport to represent the views of the Ministry of Transport.     

Cost-time Minimization in a Transportation Problem with Fuzzy Parameters: A Case Study

In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation cost as well as time of transportation when the demand, supply and transportation cost per unit of the quantities are fuzzy. The problem is modeled as multi objective linear programming problem with imprecise parameters. Fuzzy parametric programming has been used to handle impreciseness and the resulting multi objective problem has been solved by prioritized goal programming approach. A case study has been made using the proposed approach.     

Development of models for predicting roadside nitrogen dioxide concentrations and their evaluation against datasets measured in Dublin,Ireland

Different methods for predicting levels of roadside NO₂ from NO_x concentrations have been proposed. Prior work suggests that either a linear or a logarithmic relationship exists among the roadside NO₂ and NO_x concentrations. We modify and compare those methods with new formulations based on the principles of the original methods for datasets pertaining to Dublin. A new relationship based on the power law is developed to better model the decay of the ratio of (NO₂/NO_x)_road ratio with increasing NO_x concentration. These formulations are compared and examined at two study sites: at an intermittently congested urban street canyon and a free-flowing motorway.     

满堂支架法直腹板现浇箱梁横向抗推研究

满堂支架法作为一种成熟的施工技术手段,目前被大量应用于城市桥梁现浇主梁的施工项目中.具有施工方便、周转时间短和辅助设备少的优点.但对于直腹板现浇箱梁,尤其是主梁较窄的现浇箱梁,由于混凝土侧压力、倾倒混凝土产生的水平荷载以及振捣产生的水平荷载存在,使得腹板处支架存在较大的水平推力,导致整个结构处于危险状态.以某工程项目为依托,提出了两种解决方案,通过调整斜撑布置形式对结构受力状态进行改善.结果 表明,两种方案均可有效降低水平推力作用下造成结构局部应力集中的现象,有利于不利荷载均匀向整个支架结构传递.     

Federal‐state revenue sharing and resource management under outer continental shelf lands act section 8(g)

Abstract

Section 8(g) was added to the Outer Continental Shelf Lands Act (OCSLA) in 1978. It mandated sharing of the revenues from tracts that included oil and gas pools underlying the federal‐state boundary 3 miles offshore. Revenues were to be split based on agreements negotiated by the secretary of Interior and the relevant coastal state governor or “fair and equitable”; divisions made by the federal district courts. Only one agreement was concluded. Texas and Louisiana sued to force distribution of their shares of $6.1 billion in 8(g) funds held in escrow. In 1986 Congress divided the escrowed 8(g) revenues approximately 27 percent to the adjacent states and 73 percent to the federal government and legislated the same split for all future 8(g) revenues. This article examines the complex issues that section 8(g), as amended, raises for the management of federal and state submerged lands. Cooperative federal‐state approaches to implementing amended section 8(g) are reviewed. Section 8(g)'s broader implications as the only federal‐state ocean resource, revenue‐sharing mechanism currently in place also are addressed.     

Changing ownership structures in the Dutch fleet

The new Dutch shipping policy has given rise to high expectation and curiosity in the world of shipping. This, together with the obvious difficulties of an ex-post study of the effectiveness of such innovative policy, has prompted the authors to take an interest in attempting to investigate changes in ownership of the Dutch fleet 2 years after the new policy has been introduced. To do this, a rather new concept of ‘flagging out’ has been adopted, which is interpreted as a process leading to different degrees of ‘foreignness’ in a shipping operation. In this paper, a method to structure is presented, and ownership information, and changes in it are presented, that are essentially based on the theory of stochastic processes. The data used is the Dutch fleet data, which includes information on the nationality of the flag, parent ownership and management over the period 1994–1998. The results yield interesting insights in the shifts in the ownership and operational structure of shipping companies induced by the new policy. In particular, they allow one to establish the origin of new vessels, in which stage of ownership/operation it is most likely that shifts occur, and to determine the relationship between the different stages of the ‘flagging out’ process. These results, thus, enable an evaluation of the areas in which the policy can be expected to yield results.     

基于公交数据的公交乘客上客特征分析

城市公共交通是城市交通的重要组成部分,具有缓解交通拥堵、降低能源消耗、改善生态环境等优势,一直是政府大力支持与提倡优先的出行方式。基于公交的运营数据,提取了每次刷卡数据的上客站点数据,进一步分析出公交网络层面站点上客特征,最后,结合居住人口、工作人口分布,分析出公交乘客上客与空间人口分布的关联性。     

Fuzzy-logic-based incident detection for signalized diamond interchanges

This paper documents a fuzzy-logic-based incident detection algorithm for signalized urban diamond interchanges. The model is capable of detecting lane-blocking incidents whose effects are manifested by patterns of deterioration in traffic conditions that require adjustments in signal control strategies. As a component of a real-time traffic adaptive control system for signalized diamond interchanges, the algorithm feeds an incident report (i.e., the time, location, and severity of the incident) to the system's optimization manager, which uses that information to determine the appropriate signal control strategy.The performance of the model was studied using a simulation of an actual diamond interchange. The simulation study evaluated the model's performance in terms of detection rate, false alarm rate, and mean time to detect. The model's performance was encouraging, and the fuzzy-logic-based approach is considered promising.