A New Working Class: Students for a Democratic Society and the United Auto Workers in the Sixties

Honors (Bachelor's)History, Department ofUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/55464/1/bullock_amanda_history_honors_thesis2.pd

Sequence Optimization at Signalized Diamond Interchanges Using High-Resolution Event-Based Data

Signalized diamond interchanges are pairs of ramp intersections characterized by interlocked left turns and relatively close spacing. This paper describes a series of performance measures derived from high-resolution signal controller event data that can be used to optimize the internal phase sequence and offset to improve traffic flows within diamond interchanges and to assess the progression of the interior movements qualitatively and quantitatively. The new heuristic developed in this paper improves on traditional green band optimization techniques by incorporating actual demand profiles measured in the field. A field analysis was performed on a diamond interchange at I-69 and 96th Street in northwest Indianapolis, Indiana, where the existing sequence data were collected and used to model the alternative sequences to identify the optimal sequence. Interior operations were improved under the optimized settings: the percentage of vehicle arrivals on green increased by 19% during the 09:00-to-15:00 midday plan. Video observations were used to corroborate the data and are included in a video synthesis of the time–space trajectories. </jats:p

Field Cycle Length Sweep to Evaluate Resonant Cycle Sensitivity

Cycle length selection in corridor timing is often dictated by critical intersections with the highest level of saturation. Along corridors with balanced volumes and favorable link distances, a resonant cycle length is often sought to provide good progression in both directions of travel. This paper discusses the search for a resonant cycle length at a 5-intersection corridor in Fishers, Indiana over a three month period. The software traffic model suggests a reasonable range of cycle lengths from 104 seconds to 124 seconds for the corridor. This cycle length range is consistent with analytical highway capacity manual delay minimization approaches. A set of eleven cycle lengths from the 104 to 124-second range are tested over 12 weeks, with each iteration using optimized offset values generated by the Link Pivot progression optimization algorithm to maximize the percentage of vehicles arriving on green, and holding all phase splits constant. There was no obvious resonant cycle identified in the cycle length sweep, however the experiment findings indicate vehicles arriving on green decrease and travel times increase as cycle length increases.As a tradeoff, the number of force off phase terminations on the side-street phases decrease as a result of longer cycles indicating a better accommodation of sidestreet demand. Finally, a Seemingly Unrelated Regression (SURE) model was used to analyze the correlation between cycle lengths, percent of vehicles arriving on green, and travel time indicating a negative correlation between higher cycle length and progression performance

Graphical Performance Measures for Practitioners to Triage Split Failure Trouble Calls

Detector occupancy is commonly used to measure traffic signal performance. Despite improvements in controller computational power, there have been relatively few innovations in occupancy-based performance measures or integration with other data. This paper introduces and demonstrates the use of graphical performance measures based on detector occupancy ratios to verify potential split failures and other signal timing shortcomings reported to practitioners by the public. The proposed performance measures combine detector occupancy during the green phase, detector occupancy during the first five seconds of the red phase, and phase termination cause (gap out or force off). These are summarized by time of day to indicate whether the phase is undersaturated, nearly saturated, or oversaturated. These graphical performance measures and related quantitative summaries provide a first-level screening and triaging tool for practitioners to assess user concerns regarding whether sufficient green times are being provided to avoid split failures. They can also provide outcome-based feedback to staff after making split adjustments to determine whether operation improved or worsened. The paper concludes by demonstrating how the information was used to make an operational decision to re-allocate green time that reduced the number of oversaturated cycles on minor movements from 304 to 222 during a Thursday 0900-1500 timing plan and from 240 to 180 during a Friday 0900-1500 timing plan

Improving Intersection Behavior through Delay-Based Left Turn Phase Initiation

Serving protected left-turn phases for one or two vehicles can often be an inefficient use of cycle green time when the opposing through movements are over capacity. This paper assesses the performance of an intersection at which controller logic is applied to delay the call for a protected left-turn phase on the basis of vehicle wait times. During four weeks of evaluation, the delay on left-turn phase calls was varied in 25-s increments from 0 to 75 s. The results indicate that delaying left-turn phase initiation substantially increases the amount of green time for saturated through movements while minimally increasing the travel delay for left-turning drivers. The recommendation is made for agencies to consider using a delay in the range of 25 to 50 s for calling protected phases at intersections at which the opposing through movement is oversaturated and could benefit from additional green time. This paper presents one of the first quantitative studies evaluating potential intersection capacity and performance improvements with respect to left-turn detector delay. </jats:p

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Resolve and eco: the halo mass-dependent shape of galaxy stellar and baryonic mass functions

In this work, we present galaxy stellar and baryonic (stars plus cold gas) mass functions (SMF and BMF) and their halo mass dependence for two volume-limited data sets. The first, RESOLVE-B, coincides with the Stripe 82 footprint and is extremely complete down to baryonic mass Mbary ∼ 10^9.1 M⊙, probing the gas-rich dwarf regime below Mbary ∼ 10^10 M⊙. The second, ECO, covers a ~40× larger volume (containing RESOLVE-A) and is complete to Mbary ~10^9.4 M⊙. To construct the SMF and BMF we implement a new “cross-bin sampling” technique with Monte Carlo sampling from the full likelihood distributions of stellar or baryonic mass. Our SMFs exhibit the “plateau” feature starting below Mstar ~10^10 M⊙ that has been described in prior work. However, the BMF fills in this feature and rises as a straight power law below ~10^10 M⊙, as gas-dominated galaxies become the majority of the population. Nonetheless, the low-mass slope of the BMF is not as steep as that of the theoretical dark matter halo MF. Moreover, we assign group halo masses by abundance matching, finding that the SMF and BMF separated into four physically motivated halo mass regimes reveal complex structure underlying the simple shape of the overall MFs. In particular, the satellite MFs are depressed below the central galaxy MF “humps” in groups with mass < 10^13.5 M⊙ yet rise steeply in clusters. Our results suggest that satellite destruction and/or stripping are active from the point of nascent group formation. We show that the key role of groups in shaping MFs enables reconstruction of a given survey’s SMF or BMF based on its group halo mass distribution