Esma S. Gel

ORCID: 0000-0003-0472-4762
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About
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Research Areas
  • Scheduling and Optimization Algorithms
  • Advanced Queuing Theory Analysis
  • COVID-19 epidemiological studies
  • Supply Chain and Inventory Management
  • Healthcare Operations and Scheduling Optimization
  • Advanced Manufacturing and Logistics Optimization
  • Advanced Multi-Objective Optimization Algorithms
  • Assembly Line Balancing Optimization
  • Vehicle Routing Optimization Methods
  • Healthcare Policy and Management
  • Simulation Techniques and Applications
  • Optimization and Mathematical Programming
  • Manufacturing Process and Optimization
  • SARS-CoV-2 and COVID-19 Research
  • COVID-19 Pandemic Impacts
  • Consumer Market Behavior and Pricing
  • Cancer Genomics and Diagnostics
  • Hospital Admissions and Outcomes
  • Advanced Statistical Process Monitoring
  • Emergency and Acute Care Studies
  • Multi-Criteria Decision Making
  • Optimization and Packing Problems
  • Auction Theory and Applications
  • Public Health Policies and Education
  • Metaheuristic Optimization Algorithms Research

University of Nebraska–Lincoln
2022-2024

Arizona State University
2010-2021

Decision Systems (United States)
2010-2021

Northwestern University
2001

To estimate population health outcomes with delayed second dose versus standard schedule of SARS-CoV-2 mRNA vaccination.Simulation agent based modeling study.Simulated on real world US county.The simulation included 100 000 agents, a representative distribution demographics and occupations. Networks contacts were established to simulate potentially infectious interactions though occupation, household, random interactions.Simulation covid-19 vaccination prioritizing the first dose. The runs...

10.1136/bmj.n1087 article EN cc-by-nc BMJ 2021-05-12

To gain insight into the potential logistical benefits of worker cross-training and agile workforce policies, we study simple models flexible workers in serial production systems. The primary control issue is how to assign jobs/stations over time. Under assumptions complete flexibility collaborative work, prove that a expedite policy minimizes along each sample path cycle time (delay) for job. Therefore, also work process maximizes throughput every path. We compute performance improvement...

10.1080/07408170108936871 article EN IIE Transactions 2001-09-01

10.1016/j.ejor.2007.06.038 article EN European Journal of Operational Research 2007-07-05

Most of the literature in area workforce planning assumes that workers are identical. This paper considers fundamental decisions management assuming inherently different. General Cognitive Ability (GCA) is used as measure for individual differences. A mixed integer programming model developed to determine amount hiring, firing, and cross-training each GCA level minimize total costs, which include training salary firing costs missed production over multiple time periods. Two sets experiments...

10.1080/00207540600792242 article EN International Journal of Production Research 2007-02-01

Abstract We develop an Optimized Queueing Network (OQNet) capacity planning tool for supporting the design of new and reconfigured semiconductor fabrication facilities that makes use queueing network approximations optimization routine. The basic problem addressed by this is to minimize facility cost required meet specified volume cycle time targets. Features common environments, such as batch processes, re-entrant flows, multiple product classes, machine setups, are incorporated into model....

10.1080/07408170208928855 article EN IIE Transactions 2002-02-01

Next generation sequencing tests (NGS) are usually performed on relatively small core biopsy or fine needle aspiration (FNA) samples. Data is limited what amount of tumor by volume minimum number FNA passes needed to yield sufficient material for running NGS. We sought identify the PCDx NGS platform.2,723 consecutive tissues all cancer types were queried and reviewed inclusion. Information volume, success performing NGS, results compiled. Assessment sequence analysis, mutation calling...

10.1371/journal.pone.0196556 article EN cc-by PLoS ONE 2018-04-27

We consider the problem of optimal worksharing between two adjacent workers each whom processes a fixed task in addition to their shared task(s). use Markov Decision Process (MDP) model compute policies and provide benchmark for evaluating threshold policy heuristics. Our approach differs from previous studies dynamic line balancing that we focus on system architecture factors affect performance improvement opportunity possible through relative traditional static worker allocations, as well...

10.1080/07408170208928917 article EN IIE Transactions 2002-10-01

10.1016/j.ejor.2005.06.052 article EN European Journal of Operational Research 2005-10-05

ABSTRACT We present the Integrated Preference Functional (IPF) for comparing quality of proposed sets near‐pareto‐optimal solutions to bi‐criteria optimization problems. Evaluating such solution is one key issues in developing and heuristics multiple objective combinatorial The IPF a set functional that, given weight density function provided by decision maker discrete particular problem, assigns numerical value that set. This can be used compare different solutions, therefore provides...

10.1111/1540-5915.02254 article EN Decision Sciences 2003-02-01

To gain insight into the potential logistical benefits of worker cross-training and agile workforce policies, we study simple models flexible workers in serial production systems. The primary control issue is how to assign jobs/stations over time. Under assumptions complete flexibility collaborative work, prove that a expedite policy minimizes along each sample path cycle time (delay) for job. Therefore, also work process maximizes throughput every path. We compute performance improvement...

10.1023/a:1010997816249 article EN IIE Transactions 2001-01-01

10.1016/j.ejor.2004.08.044 article EN European Journal of Operational Research 2004-12-19

Abstract We study Work-In-Process (WIP)-constrained flowlines staffed by partially cross-trained workers with hierarchical skill sets. characterize the optimal worker-to-task assignment policy for CONWIP systems two and general stochastic processing times. This leads us to "fixed-before-shared" principle, which states that a flexible worker should process task he/she is uniquely qualified before helping other shared tasks. To provide insights on performance opportunity of cross-training in...

10.1080/07408170600729184 article EN IIE Transactions 2006-12-01

We consider the problem of evaluating quality solution sets generated by heuristics for multiple-objective combinatorial optimization problems. extend previous research on integrated preference functional (IPF), which assigns a scalar value to given discrete set nondominated points so that weighted Tchebycheff function can be used as underlying implicit function. This extension is useful because modeling decision maker's with reflects impact unsupported when points. present an exact...

10.1287/opre.1090.0766 article EN Operations Research 2010-01-29

ABSTRACT We investigate the impact of number human–computer interactions, different interaction patterns, and human inconsistencies in decision maker responses on convergence an interactive, evolutionary multiobjective algorithm recently developed by authors. In our context “an interaction” means choosing best worst solutions among a sample six solutions. By patterns we refer to whether preference questioning is more front‐, center‐, rear‐, or edge‐loaded. As test problems use two‐...

10.1111/deci.12180 article EN Decision Sciences 2015-09-17

This paper presents the abstraction process to support a modular approach for simulating semiconductor supply networks by modelling each node in network as 'Functional Block'. In particular, functional block represent wafer fabrication facilities is developed, which strikes suitable balance between high level and detailed complexities of manufacturing facility. We demonstrate that model able produce performance estimates (average Cycle Time (CT) Throughput (TH)) resemble behaviour real-life...

10.1504/ijspm.2007.015236 article EN International Journal of Simulation and Process Modelling 2007-01-01

We study price and lead time quotation decisions in a make-to-order system with two customer classes: (1) contract customers whose orders are practically always accepted fulfilled based on agreed at the beginning of horizon, (2) spot purchasers who arrive over quoted pair dynamically. The objective is to maximize long-run expected average profit per unit time, where from defined as revenues minus lateness penalties incurred because violations. model dynamic problem an infinite horizon Markov...

10.1287/opre.2016.1481 article EN Operations Research 2016-04-01

The capability index CPU is recommended for quality features with a unilateral specification of USL. Linearity, flatness, circularity and cylindricity are examples such features. Here, Wald statistic developed testing the equality k indices. Industrial data sets used in illustrations. procedure extended CPL indices, where to summarize process performance relative single lower limit.

10.1080/00224065.2005.11980333 article EN Journal of Quality Technology 2005-10-01

Beginning in March 2020, the United States emerged as global epicenter for COVID-19 cases with little to guide policy response absence of extensive data available reliable epidemiological modeling early phases pandemic. In ensuing weeks, American jurisdictions attempted manage disease spread on a regional basis using non-pharmaceutical interventions (i.e., social distancing), uneven burden across expansive geography exerted different implications management regions. While Arizona...

10.1371/journal.pone.0242588 article EN cc-by PLoS ONE 2020-12-02

Epidemiological models—which help us understand and forecast the spread of infectious disease—can be valuable tools for public health. However, barriers exist that can make it difficult to employ epidemiological models routinely within repertoire health planning. These include technical challenges associated with constructing models, in obtaining appropriate data model parameterization, problems clear communication modeling outputs uncertainty. To learn about unique opportunities state...

10.3389/fpubh.2024.1357908 article EN cc-by Frontiers in Public Health 2024-05-31
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