Matching Items (149)
149315-Thumbnail Image.png
Description
In today's global market, companies are facing unprecedented levels of uncertainties in supply, demand and in the economic environment. A critical issue for companies to survive increasing competition is to monitor the changing business environment and manage disturbances and changes in real time. In this dissertation, an integrated framework is

In today's global market, companies are facing unprecedented levels of uncertainties in supply, demand and in the economic environment. A critical issue for companies to survive increasing competition is to monitor the changing business environment and manage disturbances and changes in real time. In this dissertation, an integrated framework is proposed using simulation and online calibration methods to enable the adaptive management of large-scale complex supply chain systems. The design, implementation and verification of the integrated approach are studied in this dissertation. The research contributions are two-fold. First, this work enriches symbiotic simulation methodology by proposing a framework of simulation and advanced data fusion methods to improve simulation accuracy. Data fusion techniques optimally calibrate the simulation state/parameters by considering errors in both the simulation models and in measurements of the real-world system. Data fusion methods - Kalman Filtering, Extended Kalman Filtering, and Ensemble Kalman Filtering - are examined and discussed under varied conditions of system chaotic levels, data quality and data availability. Second, the proposed framework is developed, validated and demonstrated in `proof-of-concept' case studies on representative supply chain problems. In the case study of a simplified supply chain system, Kalman Filtering is applied to fuse simulation data and emulation data to effectively improve the accuracy of the detection of abnormalities. In the case study of the `beer game' supply chain model, the system's chaotic level is identified as a key factor to influence simulation performance and the choice of data fusion method. Ensemble Kalman Filtering is found more robust than Extended Kalman Filtering in a highly chaotic system. With appropriate tuning, the improvement of simulation accuracy is up to 80% in a chaotic system, and 60% in a stable system. In the last study, the integrated framework is applied to adaptive inventory control of a multi-echelon supply chain with non-stationary demand. It is worth pointing out that the framework proposed in this dissertation is not only useful in supply chain management, but also suitable to model other complex dynamic systems, such as healthcare delivery systems and energy consumption networks.
ContributorsWang, Shanshan (Author) / Wu, Teresa (Thesis advisor) / Fowler, John (Thesis advisor) / Pfund, Michele (Committee member) / Li, Jing (Committee member) / Pavlicek, William (Committee member) / Arizona State University (Publisher)
Created2010
149481-Thumbnail Image.png
Description
Surgery is one of the most important functions in a hospital with respect to operational cost, patient flow, and resource utilization. Planning and scheduling the Operating Room (OR) is important for hospitals to improve efficiency and achieve high quality of service. At the same time, it is a complex task

Surgery is one of the most important functions in a hospital with respect to operational cost, patient flow, and resource utilization. Planning and scheduling the Operating Room (OR) is important for hospitals to improve efficiency and achieve high quality of service. At the same time, it is a complex task due to the conflicting objectives and the uncertain nature of surgeries. In this dissertation, three different methodologies are developed to address OR planning and scheduling problem. First, a simulation-based framework is constructed to analyze the factors that affect the utilization of a catheterization lab and provide decision support for improving the efficiency of operations in a hospital with different priorities of patients. Both operational costs and patient satisfaction metrics are considered. Detailed parametric analysis is performed to provide generic recommendations. Overall it is found the 75th percentile of process duration is always on the efficient frontier and is a good compromise of both objectives. Next, the general OR planning and scheduling problem is formulated with a mixed integer program. The objectives include reducing staff overtime, OR idle time and patient waiting time, as well as satisfying surgeon preferences and regulating patient flow from OR to the Post Anesthesia Care Unit (PACU). Exact solutions are obtained using real data. Heuristics and a random keys genetic algorithm (RKGA) are used in the scheduling phase and compared with the optimal solutions. Interacting effects between planning and scheduling are also investigated. Lastly, a multi-objective simulation optimization approach is developed, which relaxes the deterministic assumption in the second study by integrating an optimization module of a RKGA implementation of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) to search for Pareto optimal solutions, and a simulation module to evaluate the performance of a given schedule. It is experimentally shown to be an effective technique for finding Pareto optimal solutions.
ContributorsLi, Qing (Author) / Fowler, John W (Thesis advisor) / Mohan, Srimathy (Thesis advisor) / Gopalakrishnan, Mohan (Committee member) / Askin, Ronald G. (Committee member) / Wu, Teresa (Committee member) / Arizona State University (Publisher)
Created2010
149478-Thumbnail Image.png
Description
Optimization of surgical operations is a challenging managerial problem for surgical suite directors. This dissertation presents modeling and solution techniques for operating room (OR) planning and scheduling problems. First, several sequencing and patient appointment time setting heuristics are proposed for scheduling an Outpatient Procedure Center. A discrete event simulation model

Optimization of surgical operations is a challenging managerial problem for surgical suite directors. This dissertation presents modeling and solution techniques for operating room (OR) planning and scheduling problems. First, several sequencing and patient appointment time setting heuristics are proposed for scheduling an Outpatient Procedure Center. A discrete event simulation model is used to evaluate how scheduling heuristics perform with respect to the competing criteria of expected patient waiting time and expected surgical suite overtime for a single day compared to current practice. Next, a bi-criteria Genetic Algorithm is used to determine if better solutions can be obtained for this single day scheduling problem. The efficacy of the bi-criteria Genetic Algorithm, when surgeries are allowed to be moved to other days, is investigated. Numerical experiments based on real data from a large health care provider are presented. The analysis provides insight into the best scheduling heuristics, and the tradeoff between patient and health care provider based criteria. Second, a multi-stage stochastic mixed integer programming formulation for the allocation of surgeries to ORs over a finite planning horizon is studied. The demand for surgery and surgical duration are random variables. The objective is to minimize two competing criteria: expected surgery cancellations and OR overtime. A decomposition method, Progressive Hedging, is implemented to find near optimal surgery plans. Finally, properties of the model are discussed and methods are proposed to improve the performance of the algorithm based on the special structure of the model. It is found simple rules can improve schedules used in practice. Sequencing surgeries from the longest to shortest mean duration causes high expected overtime, and should be avoided, while sequencing from the shortest to longest mean duration performed quite well in our experiments. Expending greater computational effort with more sophisticated optimization methods does not lead to substantial improvements. However, controlling daily procedure mix may achieve substantial improvements in performance. A novel stochastic programming model for a dynamic surgery planning problem is proposed in the dissertation. The efficacy of the progressive hedging algorithm is investigated. It is found there is a significant correlation between the performance of the algorithm and type and number of scenario bundles in a problem instance. The computational time spent to solve scenario subproblems is among the most significant factors that impact the performance of the algorithm. The quality of the solutions can be improved by detecting and preventing cyclical behaviors.
ContributorsGul, Serhat (Author) / Fowler, John W. (Thesis advisor) / Denton, Brian T. (Thesis advisor) / Wu, Teresa (Committee member) / Zhang, Muhong (Committee member) / Arizona State University (Publisher)
Created2010
148346-Thumbnail Image.png
Description

The thesis, titled Identifying Emerging Technologies and Techniques to Assess Indoor Environmental Quality and its Impact on Occupant Health, consists of an in-depth literature review outlining the various impacts of building factors on inhabitant health. Approximately 120 studies analyzing how environmental factors influence occupant health were reviewed and 25 were

The thesis, titled Identifying Emerging Technologies and Techniques to Assess Indoor Environmental Quality and its Impact on Occupant Health, consists of an in-depth literature review outlining the various impacts of building factors on inhabitant health. Approximately 120 studies analyzing how environmental factors influence occupant health were reviewed and 25 were used to build this literature review. The thesis provides insight into the definitions of well-being, health, and the built environment and analyzes the relationship between the three. This complex relationship has been at the forefront of academic research in recent years, especially given the impact of the COVID-19 pandemic. Essentially, an individual’s health and well-being is encompassed by their physical, mental, and social state of being. Due to the increasing amount of time spent in indoor environments the built environment influences these measures of health and well-being through various environmental factors (Indoor Air Quality, humidity, temperature, lighting, acoustics, ergonomics) defining the overall Indoor Environmental Quality. This thesis reviewed the mentioned intervention and experimental studies conducted to determine how fluctuations in environmental factors influence reported health results of occupants in the short and long term. Questionnaires, interviews, medical tests, physical measurements, and sensors were used to track occupant health measures. Sensors are also used to record environmental factor levels and are now beginning to be incorporated into the building production process to promote occupant health in healthy and smart buildings. The goal is ultimately to develop these smart and healthy buildings using study results and advancing technologies and techniques as outlined in the thesis.

ContributorsWhite, Elizabeth Mary (Author) / Wu, Teresa (Thesis director) / Wen, Jin (Committee member) / Industrial, Systems & Operations Engineering Prgm (Contributor, Contributor) / Industrial, Systems & Operations Engineering Prgm (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
131338-Thumbnail Image.png
Description
This paper describes the attempt of designing and building a two wheeled platform that is inherently unstable and discovering what tail design is suitable for stabilizing the platform. The platform is a 3D printed box that carries an Arduino, breadboard, MPU6050, a battery and a servo. This box is connected

This paper describes the attempt of designing and building a two wheeled platform that is inherently unstable and discovering what tail design is suitable for stabilizing the platform. The platform is a 3D printed box that carries an Arduino, breadboard, MPU6050, a battery and a servo. This box is connected to two continuous servo motors (one on each side) that are attached to wheels, the breadboard and Arduino are mounted on the inside and the MPU6050 is mounted on the back of the base. The MPU6050 collects the data. In the program, that data will be the position of the accelerometer’s x-axis and that data will be sent to the servo motor with the tail for the controls aspect.
ContributorsOnonye, Frank Nwachukwu (Author) / Aukes, Daniel (Thesis director) / Zhang, Wenlong (Committee member) / Engineering Programs (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
131372-Thumbnail Image.png
Description
In the last decade, a large variety of algorithms have been developed for use in object tracking, environment mapping, and object classification. It is often difficult for beginners to fully predict the constraints that multirotors place on machine vision algorithms. The purpose of this paper is to explain

In the last decade, a large variety of algorithms have been developed for use in object tracking, environment mapping, and object classification. It is often difficult for beginners to fully predict the constraints that multirotors place on machine vision algorithms. The purpose of this paper is to explain some of the types of algorithms that can be applied to these aerial systems, why the constraints for these algorithms exist, and what could be done to mitigate them. This paper provides a summary of the processes involved in a popular filter-based tracking algorithm called MOSSE (Minimum Output Sum of Squared Error) and a particular implementation of SLAM (Simultaneous Localization and Mapping) called LSD SLAM.
ContributorsVan Hazel, Colton (Author) / Zhang, Wenlong (Thesis director) / Yang, Yezhou (Committee member) / Engineering Programs (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
131375-Thumbnail Image.png
Description
In this article we present a program that is supplemental to a low-cost force-sensing quadrupedal laminate robot platform previously developed by Ben Shuch. The robot has four legs with two degrees of freedom apiece. Each leg is a four-bar mechanism controlled by two servo motors. The program that has been

In this article we present a program that is supplemental to a low-cost force-sensing quadrupedal laminate robot platform previously developed by Ben Shuch. The robot has four legs with two degrees of freedom apiece. Each leg is a four-bar mechanism controlled by two servo motors. The program that has been developed allows the user to predict the force distribution of the robot based on its configuration and the angle of the ground it is standing on. Through the use of this program, future students working on research involving this robot will be able to calculate the force distribution of the robot based on its configuration and generate ideal configurations of the robot using data gathered from force sensors attached to its feet.
ContributorsRoush, Dante Alexander (Author) / Aukes, Daniel M. (Thesis director) / Zhang, Wenlong (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
132015-Thumbnail Image.png
Description
The mean age of the world’s population is rapidly increasing and with that growth in an aging population a large number of elderly people are in need of walking assistance. In addition, a number of medical conditions contribute to gait disorders that require gait rehabilitation. Wearable robotics can be used

The mean age of the world’s population is rapidly increasing and with that growth in an aging population a large number of elderly people are in need of walking assistance. In addition, a number of medical conditions contribute to gait disorders that require gait rehabilitation. Wearable robotics can be used to improve functional outcomes in the gait rehabilitation process. The ankle push-off phase of an individual’s gait is vital to their ability to walk and propel themselves forward. During the ankle push-off phase of walking, plantar flexors are required to providing a large amount of force to power the heel off the ground.

The purpose of this project is to improve upon the passive ankle foot orthosis originally designed in the ASU’s Robotics and Intelligent Systems Laboratory (RISE Lab). This device utilizes springs positioned parallel to the user’s Achilles tendon which store energy to be released during the push off phase of the user’s gait cycle. Goals of the project are to improve the speed and reliability of the ratchet and pawl mechanism, design the device to fit a wider range of shoe sizes, and reduce the overall mass and size of the device. The resulting system is semi-passive and only utilizes a single solenoid to unlock the ratcheting mechanism when the spring’s potential force is required. The device created also utilizes constant force springs rather than traditional linear springs which allows for a more predictable level of force. A healthy user tested the device on a treadmill and surface electromyography (sEMG) sensors were placed on the user’s plantar flexor muscles to monitor potential reductions in muscular activity resulting from the assistance provided by the AFO device. The data demonstrates the robotic shoe was able to assist during the heel-off stage and reduced activation in the plantar flexor muscles was evident from the EMG data collected. As this is an ongoing research project, this thesis will also recommend possible design upgrades and changes to be made to the device in the future. These upgrades include utilizing a carbon fiber or lightweight plastic frame such as many of the traditional ankle foot-orthosis sold today and introducing a system to regulate the amount of spring force applied as a function of the force required at specific times of the heel off gait phase.
ContributorsSchaller, Marcus Frank (Author) / Zhang, Wenlong (Thesis director) / Sugar, Thomas (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
132105-Thumbnail Image.png
Description

The primary purpose of this paper is to evaluate the energy impacts of faults in building heating, ventilation, and air conditioning systems and determine which systems’ faults have the highest effect on the energy consumption. With the knowledge obtained through the results described in this paper, building engineers and technicians

The primary purpose of this paper is to evaluate the energy impacts of faults in building heating, ventilation, and air conditioning systems and determine which systems’ faults have the highest effect on the energy consumption. With the knowledge obtained through the results described in this paper, building engineers and technicians will be more able to implement a data-driven solution to building fault detection and diagnostics

In the United States alone, commercial buildings consume 18% of the country’s energy. Due to this high percentage of energy consumption, many efforts are being made to make buildings more energy efficient. Heating, ventilation, and air conditioning (HVAC) systems are made to provide acceptable air quality and thermal comfort to building occupants. In large buildings, a demand-controlled HVAC system is used to save energy by dynamically adjusting the ventilation of the building. These systems rely on a multitude of sensors, actuators, dampers, and valves in order to keep the building ventilation efficient. Using a fault analysis framework developed by the University of Alabama and the National Renewable Energy Laboratory, building fault modes were simulated in the EnergyPlus whole building energy simulation program. The model and framework are based on the Department of Energy’s Commercial Prototype Building – Medium Office variant. A total of 3,002 simulations were performed in the Atlanta climate zone, with 129 fault cases and 41 fault types. These simulations serve two purposes: to validate the previously developed fault simulation framework, and to analyze how each fault mode affects the building over the simulation period.

The results demonstrate the effects of faults on HVAC systems, and validate the scalability of the framework. The most critical fault cases for the Medium Office building are those that affect the water systems of the building, as they cause the most harm to overall energy costs and occupant comfort.

ContributorsAjjampur, Vivek (Author) / Wu, Teresa (Thesis director) / McCarville, Daniel R. (Committee member) / Industrial, Systems & Operations Engineering Prgm (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
131400-Thumbnail Image.png
Description
For the basis of this project, a particular interest is taken in soft robotic arms for the assistance of daily living tasks. A detailed overview and function of the soft robotic modules comprised within the soft robotic arm will be the main focus. In this thesis, design and fabrication methods

For the basis of this project, a particular interest is taken in soft robotic arms for the assistance of daily living tasks. A detailed overview and function of the soft robotic modules comprised within the soft robotic arm will be the main focus. In this thesis, design and fabrication methods of fabric reinforced textile actuators (FRTAs) have their design expanded. Original design changes to the actuators that improve their performance are detailed in this report. This report also includes an explanation of how the FRTA’s are made, explaining step by step how to make each sub-assembly and explain its function. Comparisons between the presented module and the function of the soft poly limb from previous works are also expanded. Various forms of testing, such as force testing, range of motion testing, and stiffness testing are conducted on the soft robotic module to provide insights into its performance and characteristics. Lastly, present plans for various forms of future work and integration of the soft robotic module into a full soft robotic arm assembly are discussed.
ContributorsSeidel, Sam (Author) / Zhang, Wenlong (Thesis director) / Sugar, Thomas (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05