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Articles 1 - 30 of 52

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Statistical Monitoring Of Queuing Networks, Yaren Bilge Kaya Oct 2018

Statistical Monitoring Of Queuing Networks, Yaren Bilge Kaya

Graduate Theses and Dissertations

Queuing systems are important parts of our daily lives and to keep their operations at an efficient level they need to be monitored by using queuing Performance Metrics, such as average queue lengths and average waiting times. On the other hand queue lengths and waiting times are generally random variables and their distributions depend on different properties like arrival rates, service times, number of servers. We focused on detecting the change in service rates in this report. Therefore, we monitored queues by using Cumulative Sum(CUSUM) charts based on likelihood ratios and compared the Average Run Length values of different ...


Understanding Transit System Performance Using Avl-Apc Data: An Analytics Platform With Case Studies For The Pittsburgh Region, Xidong Pi, Mark Egge, Jackson Whitmore, Amy Silbermann, Zhen Sean Qian Jul 2018

Understanding Transit System Performance Using Avl-Apc Data: An Analytics Platform With Case Studies For The Pittsburgh Region, Xidong Pi, Mark Egge, Jackson Whitmore, Amy Silbermann, Zhen Sean Qian

Journal of Public Transportation

This paper introduces a novel transit data analytics platform for public transit planning, assessing service quality and revealing service problems in high spatiotemporal resolution for public transit systems based on Automatic Passenger Counting (APC) and Automatic Vehicle Location (AVL) technologies. The platform offers a systematic way for users and decision makers to understand system performance from many aspects of service quality, including passenger waiting time, stop-skipping frequency, bus bunching level, bus travel time, on-time performance, and bus fullness. The AVL-APC data from September 2012 to March 2016 were archived in a database to support the development of a user-friendly web ...


Physical And Social Systems Resilience Assessment And Optimization, Daniel Romero Rodriguez May 2018

Physical And Social Systems Resilience Assessment And Optimization, Daniel Romero Rodriguez

Graduate Theses and Dissertations

Resilience has been measured using qualitative and quantitative metrics in engineering,economics, psychology, business, ecology, among others. This dissertation proposes a resilience metric that explicitly incorporates the intensity of the disruptive event to provide a more accurate estimation of system resilience. A comparative analysis between the proposed metric and average performance resilience metrics for linear and nonlinear loss and recovery functions suggests that the new metric enables a more objective assessment of resilience for disruptions with different intensities. Moreover, the proposed metric is independent of a control time parameter. This provides a more consistent resilience estimation for a given system ...


Improving Service Level Of Free-Floating Bike Sharing Systems, Aritra Pal Nov 2017

Improving Service Level Of Free-Floating Bike Sharing Systems, Aritra Pal

Graduate Theses and Dissertations

Bike Sharing is a sustainable mode of urban mobility, not only for regular commuters but also for casual users and tourists. Free-floating bike sharing (FFBS) is an innovative bike sharing model, which saves on start-up cost, prevents bike theft, and offers significant opportunities for smart management by tracking bikes in real-time with built-in GPS. Efficient management of a FFBS requires: 1) analyzing its mobility patterns and spatio-temporal imbalance of supply and demand of bikes, 2) developing strategies to mitigate such imbalances, and 3) understanding the causes of a bike getting damaged and developing strategies to minimize them. All of these ...


Space-Time Transportation System Modelling: From Traveler’S Characteristics To The Network Design Problem, Mohsen Parsafard Jun 2017

Space-Time Transportation System Modelling: From Traveler’S Characteristics To The Network Design Problem, Mohsen Parsafard

Graduate Theses and Dissertations

Traditional network design problems only consider the long-term stationary travel patterns (e.g., fixed OD demand) and short-term variations of human mobility are ignored. This study aims to integrate human mobility characteristics and travel patterns into network design problems using a space-time network structure. Emerging technologies such as location-based social network platforms provide a unique opportunity for understanding human mobility patterns that can lead to advanced modeling techniques. To reach our goal, at first multimodal network design problems are investigated by considering safety and flow interactions between different modes of transport. We develop a network reconstruction method to expand a ...


Analysis Of A Potential A(H7n9) Influenza Pandemic Outbreak In The U.S., Walter A. Silva Sotillo Jun 2017

Analysis Of A Potential A(H7n9) Influenza Pandemic Outbreak In The U.S., Walter A. Silva Sotillo

Graduate Theses and Dissertations

This dissertation presents a collection of manuscripts that describe development of models and model implementation to analyze impact of potential A(H7N9) pandemic influenza outbreak in the U.S. Though this virus is still only animal-to-human transmittable, it has potential to become human-to-human transmittable and trigger a pandemic. This work is motivated by the negative impact on human lives that this virus has already caused in China, and is intended to support public health officials in preparing to protect U.S. population from a potential outbreak of pandemic scale.

An agent-based (AB) simulation model is used to replicate the social ...


Decision Support Models For A Few Critical Problems In Transportation System Design And Operations, Ran Zhang Apr 2017

Decision Support Models For A Few Critical Problems In Transportation System Design And Operations, Ran Zhang

Graduate Theses and Dissertations

Transportation system is one of the key functioning components of the modern society and plays an important role in the circulation of commodity and growth of economy. Transportation system is not only the major influencing factor of the efficiency of large-scale complex industrial logistics, but also closely related to everyone’s daily life. The goals of an ideal transportation system are focused on improving mobility, accessibility, safety, enhancing the coordination of different transportation modals and reducing the impact on the environment, all these activities require sophisticated design and plan that consider different factors, balance tradeoffs and maintaining efficiency. Hence, the ...


Strategies For Reducing Preventable Hospital Readmissions On Medicare Patients, Andres Patricio Garcia-Arce Apr 2017

Strategies For Reducing Preventable Hospital Readmissions On Medicare Patients, Andres Patricio Garcia-Arce

Graduate Theses and Dissertations

The high expenditure of healthcare in the United States (U.S.) does not translate into better quality of care. Indeed, the U.S. healthcare system is recognized by its lack of efficiency and waste (which represents about 20% of the country’s healthcare expenses). Lack of coordination is one of the most referenced causes of waste in the U.S. healthcare system, and preventable hospital readmissions have been acknowledged to be evidence of poor coordination of care. In fiscal year 2013, the Centers for Medicare and Medicaid Services (CMS) established financial penalties for inpatient care reimbursements in hospitals with excessive ...


Optimal Bidding Strategy For A Strategic Power Producer Using Mixed Integer Programming, Sayed Abdullah Sadat Mar 2017

Optimal Bidding Strategy For A Strategic Power Producer Using Mixed Integer Programming, Sayed Abdullah Sadat

Graduate Theses and Dissertations

The thesis focuses on a mixed integer linear programming (MILP) formulation for a bi-level mathematical program with equilibrium constraints (MPEC) considering chance constraints. The particular MPEC problem relates to a power producer’s bidding strategy: maximize its total benefit through determining bidding price and bidding power output while considering an electricity pool’s operation and guessing the rival producer’s bidding price. The entire decision-making process can be described by a bi-level optimization problem. The contribution of our thesis is the MILP formulation of this problem considering the use of chance constrained mathematical program for handling the uncertainties.

First, the ...


Identifying Key Factors Of Rail Transit Service Quality: An Empirical Analysis For Istanbul, Erkan Isikli, Nezir Aydin, Erkan Celik, Alev Taskin Gumus Mar 2017

Identifying Key Factors Of Rail Transit Service Quality: An Empirical Analysis For Istanbul, Erkan Isikli, Nezir Aydin, Erkan Celik, Alev Taskin Gumus

Journal of Public Transportation

Providing a high quality of service in public transportation is essential to reduce dissatisfactions stemming from traffic congestion and noise. Public transport providers need to find ways to dilute the effects of immoderate use of private cars in big cities while maintaining a sufficient level of customer satisfaction. This study aimed to identify the key service quality (SQ) factors that drive passenger satisfaction in Istanbul’s rail transit (RT) system using data obtained from an extensive survey conducted by the Istanbul Public Transportation Co. A total of 11,116 passengers who used rail transport from May 15–June 3, 2012 ...


Optimal Demand Response Models With Energy Storage Systems In Smart Grids, Mohemmed Masooud Alhaider Nov 2016

Optimal Demand Response Models With Energy Storage Systems In Smart Grids, Mohemmed Masooud Alhaider

Graduate Theses and Dissertations

This research aims to develop solutions to relieve system stress conditions in electric grids. The approach adopted in this research is based on a new concept in the Smart Grid, namely, demand response optimization. A number of demand response programs with energy storage systems are designed to enable a community to achieve optimal demand side energy management.

The proposed models aim to improve the utilization of the demand side energy through load management programs including peak shaving, load shifting, and valley lling. First, a model is proposed to nd the optimal capacity of the battery energy storage system (BESS) to ...


Oversampling Methods For Imbalanced Dataset Classification And Their Application To Gynecological Disorder Diagnosis, Iman Nekooeimehr Jun 2016

Oversampling Methods For Imbalanced Dataset Classification And Their Application To Gynecological Disorder Diagnosis, Iman Nekooeimehr

Graduate Theses and Dissertations

In many applications, the dataset for classification may be highly imbalanced where most of the instances in the training set may belong to some of the classes (majority classes), while only a few instances are from the other classes (minority classes). Conventional classifiers will strongly favor the majority class and ignore the minority instances. The imbalance problem can occur in both binary data classification and also in ordinal regression. Ordinal regression is a supervised approach for learning the ordinal relationship between classes. Extensive research has been performed for addressing imbalanced datasets for binary classification; however, current methods do not address ...


Rule-Based Risk Monitoring Systems For Complex Datasets, Mona Haghighi Jun 2016

Rule-Based Risk Monitoring Systems For Complex Datasets, Mona Haghighi

Graduate Theses and Dissertations

In this dissertation we present rule-based machine learning methods for solving problems with high-dimensional or complex datasets. We are applying decision tree methods on blood-based biomarkers and neuropsychological tests to predict Alzheimer’s disease in its early stages. We are also using tree-based methods to identify disparity in dementia related biomarkers among three female ethnic groups. In another part of this research, we tried to use rule-based methods to identify homogeneous subgroups of subjects who share the same risk patterns out of a heterogeneous population. Finally, we applied a network-based method to reduce the dimensionality of a clinical dataset, while ...


Commuting By Customized Bus: A Comparative Analysis With Private Car And Conventional Public Transport In Two Cities, Tao Liu, Avishai Ceder, Romain Bologna, Benjamin Cabantous Jun 2016

Commuting By Customized Bus: A Comparative Analysis With Private Car And Conventional Public Transport In Two Cities, Tao Liu, Avishai Ceder, Romain Bologna, Benjamin Cabantous

Journal of Public Transportation

Commuting is a major component in the creation of traffic and travel problems. Thus, more attention should be given to its practice. Private car (PC) transport, the dominant mode of commuting in most of the world’s major cities, creates traffic-related social problems such as traffic congestion, traffic fatalities and injuries, and adverse environmental impacts. This study proposes a novel commuting travel mode—a customized bus (CB) transit system that provides advanced, personalized, and flexible demand-interactive minibus service using Internet, telephone, and smartphone apps. The aim was to assess and compare the performance of CB with PC and with conventional ...


Renewable Energy Investment Planning And Policy Design, Alireza Ghalebani Apr 2016

Renewable Energy Investment Planning And Policy Design, Alireza Ghalebani

Graduate Theses and Dissertations

In this dissertation, we leverage predictive and prescriptive analytics to develop decision support systems to promote the use of renewable energy in society. Since electricity from renewable energy sources is still relatively expensive, there are variety of financial incentive programs available in different regions. Our research focuses on financial incentive programs and tackles two main problem: 1) how to optimally design and control hybrid renewable energy systems for residential and commercial buildings given the capacity based and performance based incentives, and 2) how to develop a model-based system for policy makers for designing optimal financial incentive programs to promote investment ...


Mining Dynamic Recurrences In Nonlinear And Nonstationary Systems For Feature Extraction, Process Monitoring And Fault Diagnosis, Yun Chen Apr 2016

Mining Dynamic Recurrences In Nonlinear And Nonstationary Systems For Feature Extraction, Process Monitoring And Fault Diagnosis, Yun Chen

Graduate Theses and Dissertations

Real-time sensing brings the proliferation of big data that contains rich information of complex systems. It is well known that real-world systems show high levels of nonlinear and nonstationary behaviors in the presence of extraneous noise. This brings significant challenges for human experts to visually inspect the integrity and performance of complex systems from the collected data. My research goal is to develop innovative methodologies for modeling and optimizing complex systems, and create enabling technologies for real-world applications. Specifically, my research focuses on Mining Dynamic Recurrences in Nonlinear and Nonstationary Systems for Feature Extraction, Process Monitoring and Fault Diagnosis. This ...


Estimating Likelihood Of Having A Brca Gene Mutation Based On Family History Of Cancers And Recommending Optimized Cancer Preventive Actions, Mehrnaz Abdollahian Nov 2015

Estimating Likelihood Of Having A Brca Gene Mutation Based On Family History Of Cancers And Recommending Optimized Cancer Preventive Actions, Mehrnaz Abdollahian

Graduate Theses and Dissertations

BRCA1 and BRCA2 are gene mutations that drastically increase chances of developing breast and ovarian cancers, up to 20-fold, for women. A genetic blood test is used to detect BRCA mutations. Though these mutations occur in one of every 400 in the general population (excluding Ashkenazi Jewish ethnicity), they are present in most cases of hereditary breast and ovarian cancer patients. Hence, it is common practice for the physicians to require genetic testing for those that fit the rules as recommended by the National Cancer Comprehensive Network. However, data from the Myriad Laboratory, the only provider of the test until ...


Reliable Power System Planning And Operations Through Robust Optimization, Wei Yuan Sep 2015

Reliable Power System Planning And Operations Through Robust Optimization, Wei Yuan

Graduate Theses and Dissertations

In this dissertation, we introduce and study robust optimization models and decomposition algorithms in order to deal with the uncertainties such as terrorist attacks, natural disasters, and uncertain demand that are becoming more and more signicant in power systems operation and planning. An optimal power grid hardening problem is presented as a defender-attacker-defender (DAD) sequential game and solved by an exact decomposition algorithm. Network topology control, which is an eective corrective measure in power systems, is then incorporated into the defender-attacker-defender model as a recourse operation for the power system operator after a terrorist attack. Computational results validate the cost-eectiveness ...


Spatiotemporal Sensing And Informatics For Complex Systems Monitoring, Fault Identification And Root Cause Diagnostics, Gang Liu Sep 2015

Spatiotemporal Sensing And Informatics For Complex Systems Monitoring, Fault Identification And Root Cause Diagnostics, Gang Liu

Graduate Theses and Dissertations

In order to cope with system complexity and dynamic environments, modern industries are investing in a variety of sensor networks and data acquisition systems to increase information visibility. Multi-sensor systems bring the proliferation of high-dimensional functional Big Data that capture rich information on the evolving dynamics of natural and engineered processes. With spatially and temporally dense data readily available, there is an urgent need to develop advanced methodologies and associated tools that will enable and assist (i) the handling of the big data communicated by the contemporary complex systems, (ii) the extraction and identification of pertinent knowledge about the environmental ...


Systems Approach To Producing Electrospun Polyvinylidene Difluoride Fiber Webs With Controlled Fiber Structure And Functionality, Brian D. Bell Jan 2015

Systems Approach To Producing Electrospun Polyvinylidene Difluoride Fiber Webs With Controlled Fiber Structure And Functionality, Brian D. Bell

Graduate Theses and Dissertations

Polyvinylidene difluoride (PVDF) is a functional polymeric material that can be used for a wide variety of applications. There are many new future applications that were recently suggested for electrospun PVDF fibers. Electrospinning is a process capable of producing nano to micro sized PVDF fibers in a web. It is important to control the structure of the web during electrospinning because by controlling the structure of the web it is possible for the PVDF fiber web to have increased performance in comparison to other common forms of PVDF.

While past scientific literature focused on applications of PVDF fibers, little was ...


Achieving Reliable Generation \& Delivery Of Energy Through Robust Optimization, Anna Danandeh Jan 2015

Achieving Reliable Generation \& Delivery Of Energy Through Robust Optimization, Anna Danandeh

Graduate Theses and Dissertations

In this dissertation, we elaborate on the inherent risks and uncertainties in power systems and associated industries, and develop practical solution methods to eliminate their adverse effects.

our research agenda consists of practice-driven problems in different stages of power generation as follows. (1) Affordable fuel procurement through developing a comprehensive fuel supply chain design and operations planning system for electricity generation companies, (2) reliable electricity generation through incorporating dynamic asset rating concept in the unit commitment problem, and (3) efficient demand management through proposing a job scheduling model for effective local generation consumption.

Since reliability cannot be compromised in energy ...


Patient Populations, Clinical Associations, And System Efficiency In Healthcare Delivery System, Yazhuo Liu Jan 2015

Patient Populations, Clinical Associations, And System Efficiency In Healthcare Delivery System, Yazhuo Liu

Graduate Theses and Dissertations

The efforts to improve health care delivery usually involve studies and analysis of patient populations and healthcare systems. In this dissertation, I present the research conducted in the following areas: identifying patient groups, improving treatments for specific conditions by using statistical as well as data mining techniques, and developing new operation research models to increase system efficiency from the health institutes’ perspective. The results provide better understanding of high risk patient groups, more accuracy in detecting disease’ correlations and practical scheduling tools that consider uncertain operation durations and real-life constraints.


Reliable Design And Operations Of Infrastructure Systems, Yu An Nov 2014

Reliable Design And Operations Of Infrastructure Systems, Yu An

Graduate Theses and Dissertations

The reliability issue of the infrastructure systems has become one of the major concerns of the system operators. This dissertation is a collection of four published and working papers that address the specific reliable design and operations problems from three different application settings: transportation/telecommunications network, distribution network, and power plant. In these four projects, key random factors like site disruption and uncertain demand are explicitly considered and proper research tools including stochastic programming, robust optimization, and variants of robust optimization are applied to formulate the problems based on which the important and challenging modelling elements (nonlinear congestion, disruption caused ...


A Decision Support Model For Personalized Cancer Treatment, Florentino Antonio Rico-Fontalvo Oct 2014

A Decision Support Model For Personalized Cancer Treatment, Florentino Antonio Rico-Fontalvo

Graduate Theses and Dissertations

This work is motivated by the need of providing patients with a decision support system that facilitates the selection of the most appropriate treatment strategy in cancer treatment. Treatment options are currently subject to predetermined clinical pathways and medical expertise, but generally, do not consider the individual patient characteristics or preferences. Although genomic patient data are available, this information is rarely used in the clinical setting for real-life patient care. In the area of personalized medicine, the advancement in the fundamental understanding of cancer biology and clinical oncology can promote the prevention, detection, and treatment of cancer diseases.

The objectives ...


Novel Models And Efficient Algorithms For Network-Based Optimization In Biomedical Applications, Seyed Javad Sajjadi Jun 2014

Novel Models And Efficient Algorithms For Network-Based Optimization In Biomedical Applications, Seyed Javad Sajjadi

Graduate Theses and Dissertations

We introduce and study a novel graph optimization problem to search for multiple cliques with the maximum overall weight, to which we denote as the Maximum Weighted Multiple Clique Problem (MWMCP). This problem arises in research involving network-based data mining, specifically, in bioinformatics where complex diseases, such as various types of cancer and diabetes, are conjectured to be triggered and influenced by a combination of genetic and environmental factors. To integrate potential effects from interplays among underlying candidate factors, we propose a new network-based framework to identify effective biomarkers by searching for "groups" of synergistic risk factors with high predictive ...


Social Network Analysis Of Researchers' Communication And Collaborative Networks Using Self-Reported Data, Oguz Cimenler Jun 2014

Social Network Analysis Of Researchers' Communication And Collaborative Networks Using Self-Reported Data, Oguz Cimenler

Graduate Theses and Dissertations

This research seeks an answer to the following question: what is the relationship between the structure of researchers' communication network and the structure of their collaborative output networks (e.g. co-authored publications, joint grant proposals, and joint patent applications), and the impact of these structures on their citation performance and the volume of collaborative research outputs? Three complementary studies are performed to answer this main question as discussed below.

1. Study I: A frequently used output to measure scientific (or research) collaboration is co-authorship in scholarly publications. Less frequently used are joint grant proposals and patents. Many scholars believe that ...


Automated Localization And Segmentation Of Pelvic Floor Structures On Mri To Predict Pelvic Organ Prolapse, Sinan Onal May 2014

Automated Localization And Segmentation Of Pelvic Floor Structures On Mri To Predict Pelvic Organ Prolapse, Sinan Onal

Graduate Theses and Dissertations

Pelvic organ prolapse (POP) is a major health problem that affects women. POP is a herniation of the female pelvic floor organs (bladder, uterus, small bowel, and rectum) into the vagina. This condition can cause significant problems such as urinary and fecal incontinence, bothersome vaginal bulge, incomplete bowel and bladder emptying, and pain/discomfort. POP is normally diagnosed through clinical examination since there are few associated symptoms. However, clinical examination has been found to be inadequate and in disagreement with surgical findings. This makes POP a common but poorly understood condition. Dynamic magnetic resonance imaging (MRI) of the pelvic floor ...


Statistical And Prognostic Modeling Of Clinical Outcomes With Complex Physiologic Data, Monica A. Puertas Mar 2014

Statistical And Prognostic Modeling Of Clinical Outcomes With Complex Physiologic Data, Monica A. Puertas

Graduate Theses and Dissertations

Laboratory tests are a primary resource for diagnosing patient diseases. However, physicians often make decisions based on a single laboratory result and have a limited perspective of the role of commonly-measured parameters in enhancing the diagnostic process. By providing a dynamic patient profile, the diagnosis could be more accurate and timely, allowing physicians to anticipate changes in the recovery trajectory and intervene more effectively.

The assessment and monitoring of the circulatory system is essential for patients in intensive care units (ICU). One component of this system is the platelet count, which is used in assessing blood clotting. However, platelet counts ...


Antiviral Resistance And Dynamic Treatment And Chemoprophylaxis Of Pandemic Influenza, Sandro Paz Mar 2014

Antiviral Resistance And Dynamic Treatment And Chemoprophylaxis Of Pandemic Influenza, Sandro Paz

Graduate Theses and Dissertations

Public health data show the tremendous economic and societal impact of pandemic influenza in the past. Currently, the welfare of society is threatened by the lack of planning to ensure an adequate response to a pandemic. This preparation is difficult because the characteristics of the virus that would cause the pandemic are unknown, but primarily because the response requires tools to support decision-making based on scientific methods. The response to the next pandemic influenza will likely include extensive use of antiviral drugs, which will create an unprecedented selective pressure for the emergence of antiviral resistant strains. Nevertheless, the literature has ...


Location And Capacity Modeling Of Network Interchanges, Aldo D. Fabregas Feb 2013

Location And Capacity Modeling Of Network Interchanges, Aldo D. Fabregas

Graduate Theses and Dissertations

Network design decisions, especially those pertaining to urban infrastructure, are made by a central authority or network leader, and taking into consideration the network users or followers. These network decision problems are formulated as non-linear bi-level programming problems. In this work, a continuous network design problem (CNDP) and discrete network design problem (DNDP) bi-level optimization programs are proposed and solved in the context of transportation planning. The solution strategy involved reformulation and linearization as a single-level program by introducing the optimality conditions of the lower level problem into the upper level problem. For the CNDP, an alternative linearization algorithm (modified ...