An analysis of the commuter departure time decision

Transportation planners and transit operators alike have become increasingly aware of the need to diffuse the concentration of peak period travel in an effort to improve gasoline economy and reduce peak load requirements. An evaluation of the potential effectiveness of strategies directed to achieve this end requires an understanding of factors which affect commuter trip timing decisions. The research discussed in this article addresses this particular problem through the development and estimation of a commuter departure time (to work) choice model.A number of conclusions were drawn based on the departure time model results and related analyses. It was found that work schedule flexibility, mode, occupation, income, age, and transportation level of service all influence departure time choice. The uncertainty in work arrival time and the consequences of various work arrival times may also be determinants of commuter departure time choice.The estimated model represents improvements over previous work in that it more explicitly considers work arrival time uncertainty and travelers' perceived loss associated with varying work arrival times, and additional socio-demographic factors which can potentially affect departure time choice. Furthermore, the estimated model includes consideration of transit commuters, in addition to single occupant auto and carpool work travelers. The inclusion of transit commuters represents a particularly important contribution for policy analysis, since the model could potentially be used to study the effect of service and employment policies on transit system peak load requirements.     

IN VITRO GLYCATION OF HEMOGLOBIN (HB):CHOOSING THE APPROPRIATE MODEL

ＩＮＶＩＴＲＯＧＬＹＣＡＴＩＯＮＯＦＨＥＭＯＧＬＯＢＩＮ（ＨＢ）：ＣＨＯＯＳＩＮＧＴＨＥＡＰＰＲＯＰＲＩＡＴＥＭＯＤＥＬＦａｎｇＺｈｉｙｕ；Ｒ．Ｒ．Ｌｉｔｔｌｅ，Ｈ．Ｍ．Ｗｉｅｄｍｅｙｅｒ，Ｄ．Ｅ．Ｇｏｌｄｓｔｅｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｉｌ...     

Research contributions to managing transit service reliability

Service reliability problems are a major concern shared by transit system users and operators. Unreliable service leads to additional vehicle requirements and higher operating costs; passengers suffer increased wait time and higher travel time uncertainty, leading to a general dissatisfaction with service and the possibility of seeking other means of transport. Because of the significance of this problem, considerable research attention has been focused in recent years on developing ways to improve service reliability. This paper examines contributions which have been made to managing transit service reliability. This topic encompasses the subjects of vehicle run time, run time variation, headway variation, passenger wait time, and reliability control. Both theoretical and empirical approaches have been undertaken, and each has contributed to our knowledge in addressing the overall problem. Significant contributions to the state-of-the-art are reported and the implications on present practice are discussed.     

Crosswind Sensitivity of Passenger Cars and the Influence of Chassis and Aerodynamic Properties on Driver Preferences

Results of vehicle crosswind research involving both full-scale driver-vehicle tests and associated analyses are presented. The paper focuses on experimental crosswind testing of several different vehicle configurations and a group of seven drivers. A test procedure, which utilized wind-generating fans arranged in alternating directions to provide a crosswind “gauntlet”, is introduced and described. Driver preferences for certain basic chassis and aerodynamic properties are demonstrated and linked to elementary system responses measured during the crosswind gauntlet tests. Based on these experimental findings and confirming analytical results, a two-stage vehicle design process is then recommended for predicting and analyzing the crosswind sensitivity of a particular vehicle or new design.     

Environmental changes in the western Black Sea related to anthropogenic and natural conditions

The Black Sea northwestern shelf (NWS) ecosystem has been subjected to the strongest anthropogenic pressure of the entire Black Sea as about 80% of the freshwater runoff is discharged there.This paper presents a review of the global environmental changes related mainly to increased eutrophication in the western Black Sea basin.A case study (CoMSBlack 92a cruise) attempts to highlight the interaction of some natural and anthropogenic factors responsible for specific chemical and biological features in the western Black Sea environment. The significance of processes located near the Danube river mouth, which, due to their relatively small space scale, have not been recognized before, is clarified. Hydrological processess of specific importance to the distribution and transformation of antropogenic inputs are river plume dynamics, coastal upwelling and mixing and downwelling over the shelf break and slope in this part of the basin. A layer of low hydrological variability (“conservative layer”) appears to be a natural feature of the area, hypothesized to precondition specific biological and chemical processes there.The results suggest that the interplay between the Danube anthropogenic nutrient load with the natural hydrological fronts and gradients provides opportunities for enhanced biological activity thus contributing to the global environmental changes in the Black Sea NWS.     

Application of Inverse Models to Vehicle Optimization Problems

This paper presents a nonlinear inverse model of a road vehicle which simulates combined steering and braking/driving. The inputs to the model are the lateral and longitudinal acceleration of the vehicle's sprung mass center. The simulation returns the steering wheel angle and brake/drive torques required to obtain the desired accelerations. An example is presented which demonstrates the utility of inverse models for optimization purposes.