3,444 research outputs found
Towards Implementation of Max-Pressure Signal Timing on Minnesota Roads
No full textMax-pressure control is a new adaptive method for signal timing that is mathematically proven to achieve maximum throughput for the entire city road network. This throughput guarantee is nevertheless achieved by a decentralized control algorithm that depends only on local traffic information and is easy to compute. These mathematical properties suggest high potential for use in Minnesota, but the method?s performance in practice is not well-known. Furthermore, it lacks some practical constraints on signal timing that could cause confusion to drivers.
This project conducted methodological improvements and simulation experiments on a calibrated model of 7 intersections in Hennepin County. We modified the theory behind max-pressure control to model first-in-first-out behaviors on lanes shared by multiple turning movements, and to force max-pressure control to follow a signal cycle. After making these significant methodological improvements, we proved that the maximum throughput properties still hold. Then, we calibrated SUMO (Simulation of Urban MObility) microsimulation models of 2 Hennepin County corridors with 7 intersections using signal timing data and 15-minute observed counts, and compared different versions of max-pressure control with existing actuated-coordinated signals. We varied the maximum cycle length and the time step (signal phases can only change once per time step). The performance depended on the control parameters. Overall, for most intersections and demand periods, we were able to find max-pressure control settings that significantly improved over current signal timings. Large reductions in delay (sometimes over 50%) suggested that max-pressure signal timing both achieved higher throughput during peak demand and was more responsive to queues.Barman, Simanta; Levin, Michael W.; Robbennolt, Jake; Hu, Jeffrey; Odell, Michael; Kang, Di. (2022). Towards Implementation of Max-Pressure Signal Timing on Minnesota Roads. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/252754
Approximating min-max k-clustering
No full textWe consider the
problems
of set partitioning into clusters with minimum of the maximum cost of a cluster. The cost function is given by an oracle, and we assume that it satisfies some natural structural constraints. That is, we assume that the cost function is monotone, the cost of a singleton is zero, and we assume that for all the following holds
. For this problem we present
a -approximation algorithm for , a
2-approximation algorithm for , and we also show a lower
bound of on the performance guarantee of any
polynomial-time algorithm.
We then consider special cases of this problem arising in vehicle routing problems, and present improved results
"The Consolidated Assistance Program, Reforming Welfare by Synchronizing Public Assistance Benefits"
No full textLevin-Waldman examines the structure of existing welfare programs and concludes that the current array of benefits could be synchronized and consolidated to create a new system that would provide economic incentives to work. He suggests combining elements of the earned income tax credit (EITC) and current welfare programs into one program, a consolidated assistance program (CAP). Levin-Waldman argues that a program composed of an assistance component (with one set of benefits for working parents and a different set for nonworking parents) and a child support component could be designed to assure minimal subsistence to those unable to work while providing incentives for those on welfare to work without, in effect, penalizing them for getting off welfare. Such a program would reform welfare more expeditiously than a plan that would simply expand the EITC or put a time limit on welfare benefits. Moreover, such a plan would not necessarily add to the national budget deficit.
Head of Schmarya Levin (1867-1935) 20th century
No full textThe sitter was a Russian-born writer and Zionist. Signed and numbered 2/25 in lower left.Mrs. Zeno Darmstadter, New York.Digital imageDr. Schmarya Levin (1867-1935) was a well-known author and Zionist leader
Flier for a concert featuring World/Inferno, Friendship Society, The Max Levine Ensemble at the Peoples Media Center at Al Fishawy, March 21
No full textFlier for a concert featuring World/Inferno, Friendship Society, The Max Levine Ensemble and 1 TBA at the Peoples Media Center at Al Fishawy on Friday, March 21
On the max coloring problem
No full textAbstractWe consider max coloring on hereditary graph classes. The problem is defined as follows. Given a graph G=(V,E) and positive node weights w:V→(0,∞), the goal is to find a proper node coloring of G whose color classes C1,C2,…,Ck minimize ∑i=1kmaxv∈Ciw(v). We design a general framework which allows to convert approximation algorithms for standard node coloring into algorithms for max coloring. The approximation ratio increases by a multiplicative factor of at most e for deterministic offline algorithms and for randomized online algorithms, and by a multiplicative factor of at most 4 for deterministic online algorithms.We consider two specific hereditary classes which are interval graphs and perfect graphs. For interval graphs, we study the problem in several online environments. In the List Model, intervals arrive one by one, in some order. In the Time Model, intervals arrive one by one, sorted by their left endpoints. For the List Model we design a deterministic 12-competitive algorithm, and a randomized 3e-competitive algorithm. In addition, we prove a lower bound of 4 on the competitive ratio of any deterministic or randomized algorithm. For the Time Model, we use simplified versions of the algorithm and the lower bound of the List Model, to develop a deterministic 4-competitive algorithm, a randomized e-competitive algorithm, and to design a lower bounds of ϕ≈1.618 on the deterministic competitive ratio and a lower bound of 43 on the randomized competitive ratio. The former lower bounds hold even for unit intervals. For unit intervals in the List Model, we obtain a deterministic 8-competitive algorithm, a randomized 2e-competitive algorithm and lower bounds of 2 on the deterministic competitive ratio and 116≈1.8333 on the randomized competitive ratio.Finally, we employ our framework to obtain an offline e-approximation algorithm for max coloring of perfect graphs, improving and simplifying a recent result of Pemmaraju and Raman
Oral History Interview: Henry Wortis (1371)
No full textAbstract: In his March 2005 interview with Matt Levin, Henry Wortis discusses his involvement in the Labor Youth League while an undergraduate at the University of Wisconsin-Madison. He details the group?s membership, activities, and relationship with the wider array of leftist political ideologies, emphasizing the growing division between the Old Left and youth in the LYL. This interview was originally conducted for the author?s research for Cold War University and has been submitted for inclusion into the UW-Madison Oral History Program
In Their Time: The Riddle Behind the Epistolary Friendship Between Ernest Hemingway and Ivan Kashkin
No full textDetails Hemingway’s relationship with his Russian translator, critic, epistolary friend, and later biographer Ivan Kashkin. Despite Kashkin’s merciless assessments of Hemingway’s mental health and writing, Hemingway remained loyal to his friend, honoring Kashkin by naming one of the Soviet fighters in For Whom the Bell Tolls after him. Suggesting that each author was the other’s alter ego, Levin examines Kashkin’s poetry and tragic life in the context of their shared generation
Levitansky family genealogy 1980
No full textA genealogy of the Levitansky family beginning in 1794, originally from Suwalki, Poland, including photographs, newspaper clippings and descriptions of family events. The family claims heritage from 15th century Spain as well as a clan name "Baranis." Among the descendants are Boris-Leavitt, founder of Lana Lobell women's mail-order house, Dr. Samuel A. Levine, a prominent cardiologist, Dr. Abraham L. Levin, medical inventor, and Dr. Max Levine, bateriologist. A copy of a letter to latter from MIT (1913) shows difficulty a Jew faced in finding employment. A relationship with the Paradisthal (or Paradise) family of Chicago is notedGift of Etta L. Levi
- …
