Document

A Service System with On-Demand Agents, Stochastic Gradient Algorithms and the SARAH Algorithm

About this Digital Document

We consider a system, where a random flow of customers is served by agents invited on-demand. Each invited agent arrives into the system after a random time, and leaves it with some probability after each service completion. Customers and/or agents may be impatient. The objective is to design a real-time adaptive invitation scheme that minimizes customer and agent waiting times.We study some aspects of the SGD method with a fixed, large learning rate and propose a novel assumption of the objective function, under which this method has improved convergence rates. We also propose a convergence analysis of SGD within a diminishing learning rate regime without bounded gradient assumption in the strongly convex case.We propose the SARAH algorithm for solving finite-sum minimization problems in the strongly convex, convex, and nonconvex cases. We also consider a general stochastic optimization problem by using the SARAH algorithm with inexactness.

Full Title
A Service System with On-Demand Agents, Stochastic Gradient Algorithms and the SARAH Algorithm
Contributor(s)
Creator: Nguyen, Lam
Thesis advisor: Scheinberg, Katya
Publisher
Lehigh University
Date Issued
2018-08
Language
English
Type
Form
electronic documents
Department name
Industrial Engineering
Digital Format
electronic documents
Media type
Creator role
Graduate Student

Citation


        
      
@mastersthesis{nguyen2018,
  title = {A Service System with On-Demand Agents, Stochastic Gradient Algorithms and the SARAH Algorithm},
  author = {Nguyen, Lam},
  year = {2018},
  month = aug,
  publisher = {Lehigh University},
  keywords = {Industrial engineering},
  abstract = {We consider a system, where a random flow of customers is served by agents invited on-demand. Each invited agent arrives into the system after a random time, and leaves it with some probability after each service completion. Customers and/or agents may be impatient. The objective is to design a real-time adaptive invitation scheme that minimizes customer and agent waiting times.We study some aspects of the SGD method with a fixed, large learning rate and propose a novel assumption of the objective function, under which this method has improved convergence rates. We also propose a convergence analysis of SGD within a diminishing learning rate regime without bounded gradient assumption in the strongly convex case.We propose the SARAH algorithm for solving finite-sum minimization problems in the strongly convex, convex, and nonconvex cases. We also consider a general stochastic optimization problem by using the SARAH algorithm with inexactness.},
  language = {English},
}