Branching Rules for Minimum Congestion Multi-Commodity Flow Problems

In this paper, we examine various branch and bound algorithms for a minimum congestion origin-destination integer multi-commodity flow problem. The problem consists of finding a routing such that the congestion of the most congested arc is minimum. For our implementation, we assume that all demands are known a priori. We provide a mixed integer linear programming formulation of our problem and propose various new branching rules to solve the model. For each rule, we provide theoretical and experimental proof of their effectiveness. In order to solve large instances, that more accurately portray real-world applications, we outline a path formulation model of our problem. We provide two methods for implementing our branching rules using branch and price

Neurophysiology for Allied Health Students, Book 1: The Basics

[Extract] Neurophysiology is all about how the nervous system communicates information. The nervous system is the master controller of bodily functions. The basic functional unit is the neuron and the neurons communicate within themselves and from one neuron to another to allow us to move, to think, to breathe, to read, to remember and to learn. So how do neurons and the nervous system do all of this? This book is intended to help you understand the broad overview of how the nervous system works

Can a Default Option Reduce Default Rates?

Starting in 2008, major changes to the federal student loan system have increased the generosity and flexibility of repayment options. In theory, these efforts should reduce the effect of the business cycle on default patterns. However, since 2007, student loan default rates have persisted in rising. In response, several student loan advocates have proposed replacing the standard program with the income-based repayment program as the automatic repayment option. This stakeholder analysis explores the potential of this proposal from the perspective of borrowers, academic institutions, and student loan servicers through a literature review of empirical research of student loan default behaviors, quantitative analysis of cohort default rates, and exploratory interviews. This research does not strongly support the broad statement that automatic enrollment in income-based repayment would eliminate the problem of student loan defaults. However, of all repayment options, the income -based is best suited to meet the needs of financially stressed borrowers, and the stakeholder analysis uncovers some practical opportunities to leverage current infrastructures and institutional needs to improve outcomes. This analysis recommends that the Department of Education consider piloting two default reduction efforts in order to promote income-based repayment programs: (1) partner with schools that have the largest number of associated defaulted loans to develop targeted counseling services prior to loan disbursement and (2) partner with servicers to test the effectiveness of making the income-based repayment program the automatic option upon entering into repayment. Though the income-based repayment program will not fully solve the problem of the rising burden of student loans, it provides a promising structure to reduce the financial burden of higher education debt

The Effect of Symmetry Lowering on the Dielectric Response of BaZrO3BaZrO_3

We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO$_3$ perovskite. A previous study [Arkbarzadeh {\em et al.} Phys. Rev. B {\bf 72}, 205104 (2005)] reported a disagreement between experimental and theoretical low temperature dielectric constant $\epsilon$ for the high symmetry BaZrO$_3$ structure. We show that a fully relaxed 40-atom BaZrO$_3$ structure exhibits O$_6$ octahedral tilting, and $\epsilon$ that agrees with experiment. The change in $\epsilon$ from high-symmetry to low-symmetry structure is due to increased phonon frequencies as well as decreased mode effective charges.Comment: 4 pages, 2 figure