Passenger transmission and productiveness of transit lines with high loads

Deterministic transit capacity analysis applies to planning, design and operational management of urban transit systems. The Transit Capacity and Quality of Service Manual (1) and Vuchic (2, 3) enable transit performance to be quantified and assessed using transit capacity and productive capacity. This paper further defines important productive performance measures of an individual transit service and transit line. Transit work (p-km) captures the transit task performed over distance. Passenger transmission (p-km/h) captures the passenger task delivered by service at speed. Transit productiveness (p-km/h) captures transit work performed over time. These measures are useful to operators in understanding their services’ or systems’ capabilities and passenger quality of service. This paper accounts for variability in utilized demand by passengers along a line and high passenger load conditions where passenger pass-up delay occurs. A hypothetical case study of an individual bus service’s operation demonstrates the usefulness of passenger transmission in comparing existing and growth scenarios. A hypothetical case study of a bus line’s operation during a peak hour window demonstrates the theory’s usefulness in examining the contribution of individual services to line productive performance. Scenarios may be assessed using this theory to benchmark or compare lines and segments, conditions, or consider improvements

How structure sculpts function: Unveiling the contribution of anatomical connectivity to the brain's spontaneous correlation structure

Intrinsic brain activity is characterized by highly organized co-activations between different regions, forming clustered spatial patterns referred to as resting-state networks. The observed co-activation patterns are sustained by the intricate fabric of millions of interconnected neurons constituting the brain's wiring diagram. However, as for other real networks, the relationship between the connectional structure and the emergent collective dynamics still evades complete understanding. Here, we show that it is possible to estimate the expected pair-wise correlations that a network tends to generate thanks to the underlying path structure. We start from the assumption that in order for two nodes to exhibit correlated activity, they must be exposed to similar input patterns from the entire network. We then acknowledge that information rarely spreads only along a unique route but rather travels along all possible paths. In real networks, the strength of local perturbations tends to decay as they propagate away from the sources, leading to a progressive attenuation of the original information content and, thus, of their influence. Accordingly, we define a novel graph measure, topological similarity, which quantifies the propensity of two nodes to dynamically correlate as a function of the resemblance of the overall influences they are expected to receive due to the underlying structure of the network. Applied to the human brain, we find that the similarity of whole-network inputs, estimated from the topology of the anatomical connectome, plays an important role in sculpting the backbone pattern of time-average correlations observed at rest.This work was supported by (R.G.B.) the FI-DGR scholarship of the Catalan Government through the Age`ncia de Gestio d’Ajuts Universitari i de Recerca, under Agreement No. 2013FI-B1-00099, (G.Z.L.) the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 720270 (HBP SGA1), (G.D.) the European Research Council Advanced Grant: DYSTRUCTURE (295129) and the Spanish Research Project No. PSI2013- 42091-P, (Z.K.) European Community’s Seventh Framework Programme [FP7/2007-2013] under agreement PITN-GA- 2011-290011, (V.M.K.) European Community’s Seventh Framework Programme [FP7/2007-2013] under Agreement No. PITN-GA-2012-316746 and (M.L.K.) by the European Research Council Consolidator Grant No. CAREGIVING (615539)

Fine-scale computations for adaptive processing in the human brain

Adapting to the environment statistics by reducing brain responses to repetitive sensory information is key for efficient information processing. Yet, the fine-scale computations that support this adaptive processing in the human brain remain largely unknown. Here, we capitalise on the sub-millimetre resolution of ultra-high field imaging to examine functional magnetic resonance imaging signals across cortical depth and discern competing hypotheses about the brain mechanisms (feedforward vs. feedback) that mediate adaptive processing. We demonstrate layer-specific suppressive processing within visual cortex, as indicated by stronger BOLD decrease in superficial and middle than deeper layers for gratings that were repeatedly presented at the same orientation. Further, we show altered functional connectivity for adaptation: enhanced feedforward connectivity from V1 to higher visual areas, short-range feedback connectivity between V1 and V2, and long-range feedback occipito-parietal connectivity. Our findings provide evidence for a circuit of local recurrent and feedback interactions that mediate rapid brain plasticity for adaptive information processing

INVESTIGATING TRANSIT PRODUCTION AND PERFORMANCE: A PROGRAMMING APPROACH

This analysis extends prior research on efficiency and productivity in transit systems using an extensive panel data set. First, efficiency rankings and efficient subsets of transit systems are obtained through data envelopment analysis (DEA), a non-parametric linear programming-based methodology. Based on the results of the DEA analysis, globally efficient frontier production functions are then built in the context of transit operations in the United States. The results indicate that when jointly considered, there is an improvement on both the theoretical and empirical aspects of examining efficiency and production in transit systems. Results also suggest that efficiency and returns to scale findings differ substantially depending on the evaluation methodology. Directions for further research are suggested

OPERATING SUBSIDIES AND PERFORMANCE IN PUBLIC TRANSIT: AN EMPIRICAL STUDY

The primary objective of this paper is to analyze the effect of operating subsidies on transit performance. In addition to identifying the overall effect of subsidies, this paper examines whether subsidies have had differential performance impacts that depend upon system size and subsidy source. Data for the analysis come from fixed-route bus systems in the state of Indiana over a 12-year period (1983-1994). The next section reviews previous work analyzing the effects of subsidies on bus transit performance and Section 3 presents the econometric methodology used in the paper. Section 4 summarizes the available data, presents the estimated models, and interprets the results. Section 5 provides some insights on the problem of causality between performance and subsidization. Section 6 analyzes the expected effects of redistributing subsidies more towards local sources and Section 7 offers concluding comments

COST STRUCTURES OF PUBLIC TRANSIT SYSTEMS: A PANEL DATA ANALYSIS

This paper explores whether public transit production technology differs by size and operating characteristics of the transit system. Previous cost studies have generated conflicting results on public transit production technologies because they have employed various sub-samples of public transit properties. The diverse results from these studies may either reflect alternative technologies or sampling differences. The analysis presented in this paper is unique because rather than focusing upon a relatively small subset of public transit firms, this study includes nearly all transit systems reporting for Section 15 (U.S. National Transit Data) purposes from 1986 to 1994. Results indicate that U.S. transit properties are heterogeneous with different production technologies, which implies that transit cost analyses based upon a set of heterogeneous systems will generate incorrect inferences on public transit costs and production structures. Whether own price elasticities for inputs, elasticities of substitution between inputs in the production of public transit or scale economies are examined, there will be differences in these measures by size of public transit firm. Consistent with expectations, the largest systems operated with the greatest returns to capacity utilization and have the highest estimated average cost of production

Silver Spade Theatre Restaurant

Emergency response systems in urban areas should be located to ensure adequate coverage and rapid response time. We develop a model for locating emergency vehicles on urban networks considering both spatial and temporal demand characteristics such as the probability that a server is not available when required. We also consider that service rates are not identical but may vary among servers and are dependent upon incident characteristics: corresponding districting and dispatching problems are also integrated in the location model. The model is applied using real data for locating freeway service patrol vehicles and results are compared with existing coverage and median models. Results show improvements in the mean response time particularly in cases of high demand for intervention when compared to 'traditional' models