Impact of information technology on the methods and working systems of the freight forwarding industry

Freight forwarding fulfils the role of information processor. The past decade has seen considerable change in the information industry. Combine these two facts and we can begin to explain why freight forwarders have a vested interest in using computer based information systems to their full. Many organizations have tried, some with considerable success, but in others a lack of real commitment and professionalism has cost considerable sums. In this paper the background to the industry is reviewed together with an analysis of the reasons for the poor implementation of successful systems.     

TBM及其在中国的应用(2)

3工程和技术实例 3.1在长大和深埋隧道工程方面其它国家的经验 3.1.1工程实例 在国际上,许多地铁、公路和水利方面的隧道正投入使用或正在建设之中,还有的才处于计划阶段.     

TBM及其在中国的应用(3)

3.6先进的掘进及支护系统 3.6.1其他先进的掘进技术 除了上述的各种主要的先进TBM技术外,还有下列几种先进的地下掘进技术:     

A combined land use-transportation model when zonal travel demand is endogenously determined

A combined transportation-land use model is proposed in this paper. Unlike other existing urban land use and transportation planning models in which a “fixed demand” for services is assumed to be known at the zonal level of an urban area, zonal travel demand is endogenously determined together with link congestion costs, optimal amounts of production and resulting efficient densities of land uses, once the transportation network is given. Some characteristics of alternative solutions are demonstrated. The proposed model represents progress over previous efforts in combining land use-transportation problems since the travel choice as to origin, destination and routes as well as amounts of goods to be produced at the optimal density of land uses are integrated into a consistent mathematical programming framework.     

Investigation of active torsion bar actuator configurations to reduce vehicle body roll

The increasing popularity of sport utility/light-duty vehicles has prompted the investigation of active roll management systems to reduce vehicle body roll. To minimize vehicle body roll and improve passenger comfort, one emerging solution is an active torsion bar control system. The validation of automotive safety systems requires analytical evaluation and laboratory testing prior to implementation on an actual vehicle. In this article, a computer simulation tool and accompanying hardware-in-the-loop test environment are presented for active torsion bar systems to study component configurations and performance limits. The numerical simulation illustrates that the hydraulic cylinder extension limits the active torsion system's ability to provide body roll angle reduction under various driving conditions. To compare the control system's time constant and body roll minimization capabilities for different hydraulic valve assemblies and equivalent hose lengths, an experimental test stand was created. For a typical hydraulic pressure and hose diameter, the equivalent hose length was not a key design variable that impacted the system response time. However, the servo-valve offered a quicker transient response and smoother steady-state behavior than the solenoid poppet actuators that may increase occupant safety and comfort.     

Recent advances in automotive technology and the cost-effectiveness of fuel economy improvement

The potential for improving the fuel economy of conventional, gasoline-powered automobiles through optimized application of recent technology advances is analyzed. Results are presented at three levels of technical certainty, ranging from technologies already in use to technologies facing technical constraints (such as emissions control problems) which might inhibit widespread use. A fleet-aggregate, engineering-economic analysis is used to estimate a range of U.S. new car fleet average fuel economy levels achievable given roughly 10 years of lead time. Technology cost estimates are compared to fuel savings in order to determine likely cost-effective levels of fuel economy, which are found to range from 39 miles per gallon to 51 miles per gallon depending on technology certainty level. The corresponding estimated increases in average new car price range from $540 to $790 (1993$). Estimated fuel savings payback times average less than 3 years and the cost of conserved energy averages $0.50 per gallon, indicating that these levels of fuel economy improvement are cost-effective over a vehicle lifetime. A vehicle stock turnover model is used to project the reductions in gasoline consumption and associated emissions that would follow if the estimated fuel economy levels are achieved. Potential trade-offs regarding vehicle performance, safety, and emissions are also discussed.     

Consequences of public ownership and subsidies for mass transit: Evidence from case studies and regression analysis

The trend toward public ownership, public regulation, and public subsidization of the U.S. transit industry has recently come under attack. Many argue that the result has been reduced productivity, increased costs, and very little real benefit. This article examines the impacts of subsidies and public ownership in four large transit systems that cover a range of transit system types and financing arrangements. Evidence from the case studies is compared to the results of both time-series and cross-section regression analysis of operating and financial statistics for large samples of bus systems. Although the case studies and the regressions rely on different datasets and different techniques, they support the same conclusions. Increased subsidies and public ownership have kept down fares and permitted service expansion, but have also encouraged wasteful cost escalation. Thus, transit riders unquestionably have benefited from public takeovers of transit systems and burgeoning subsidies, but not nearly as much as they would have benefited if costs had not skyrocketed at the same time.     

Breaking car use habits: The effectiveness of a free one-month travelcard

Based on calls for innovative ways of reducing car traffic and research indicating that car driving is often the result of habitual decision-making and choice processes, this paper reports on a field experiment designed to test a tool aimed to entice drivers to skip the habitual choice of the car and consider using—or at least trying—public transport instead. About 1,000 car drivers participated in the experiment either as experimental subjects, receiving a free one-month travelcard, or as control subjects. As predicted, the intervention had a significant impact on drivers’ use of public transport and it also neutralized the impact of car driving habits on mode choice. However, in the longer run (i.e., four months after the experiment) experimental subjects did not use public transport more than control subjects. Hence, it seems that although many car drivers choose travel mode habitually, their final choice is consistent with their informed preferences, given the current price–quality relationships of the various options.