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Articles 6421 - 6450 of 13799

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

Search And Rescue Operations Forecasting And Optimization, Zachary T. Hornberger Mar 2019

Search And Rescue Operations Forecasting And Optimization, Zachary T. Hornberger

Theses and Dissertations

United States Coast Guard District 14 is responsible for the execution of eleven statutory missions across the Pacific region. Despite having the largest geographic area of responsibility (AOR), District 14 has command of among the fewest resources to accomplish these missions. When search and rescue (SAR) emergencies occur, these events take immediate priority because the ability to rapidly coordinate available assets can be the difference between saving or losing a life. Using historic records of SAR incidents for District 14, we leverage an approach called the stochastic zonal distribution model to evaluate spatiotemporal trends in emergency rates and response strategies …


Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum Mar 2019

Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum

Theses and Dissertations

Continuing improvement in the field of AM of metals provides the opportunity for direct fabrication of aerospace parts. AM was once used in large part for rapid prototyping but improvements in technology and increases in the knowledge base of AM materials has provided the opportunity for manufacture of AM parts for operational use. The ability to create low numbers of unique parts without having to invest in expensive tooling provides great economic incentive to utilize this technique. IN718 is the most common high temperature alloy used in the aerospace industry and lends itself readily to formation by LPBF. The superior …


Graph Formalisms And Technologies To Support To Systems Engineering Modeling And Analysis, Mil'yonta Williams Mar 2019

Graph Formalisms And Technologies To Support To Systems Engineering Modeling And Analysis, Mil'yonta Williams

Research Horizons Day Posters

No abstract provided.


A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter Mar 2019

A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter

PRC-Affiliated Research

Physics-based modeling of metal additive manufacturing (AM) processes is computationally challenging due to the very fine meshing required in both time and space. State-of-the-art numerical models that offer great insight into the process have been developed, but they require powerful computational resources and weeks of processing time. Thus, it is often more time-effective to fabricate multiple builds within the time it takes to complete one simulation prediction, further reinforcing the current trial-and-error approach to optimizing the build parameters. This study presents a simplified approach to the transient thermal modeling of the AM process. The numerical model is designed to run …


A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter Mar 2019

A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter

PRC-Affiliated Research

Physics-based modeling of metal additive manufacturing (AM) processes is computationally challenging due to the very fine meshing required in both time and space. State-of-the-art numerical models that offer great insight into the process have been developed, but they require powerful computational resources and weeks of processing time. Thus, it is often more time-effective to fabricate multiple builds within the time it takes to complete one simulation prediction, further reinforcing the current trial-and-error approach to optimizing the build parameters. This study presents a simplified approach to the transient thermal modeling of the AM process. The numerical model is designed to run …


A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter Mar 2019

A 3d Finite Difference Thermal Model Tailored For Additive Manufacturing, Tom Stockman, Judith A. Schneider, Bryant Walker, John S. Carpenter

PRC-Affiliated Research

Physics-based modeling of metal additive manufacturing (AM) processes is computationally challenging due to the very fine meshing required in both time and space. State-of-the-art numerical models that offer great insight into the process have been developed, but they require powerful computational resources and weeks of processing time. Thus, it is often more time-effective to fabricate multiple builds within the time it takes to complete one simulation prediction, further reinforcing the current trial-and-error approach to optimizing the build parameters. This study presents a simplified approach to the transient thermal modeling of the AM process. The numerical model is designed to run …


An Integrated Approach For Remanufacturing Job Shop Scheduling With Routing Alternatives., Ling Ling Li, Cong Bo Li, Li Li, Ying Tang, Qing Shan Yang Mar 2019

An Integrated Approach For Remanufacturing Job Shop Scheduling With Routing Alternatives., Ling Ling Li, Cong Bo Li, Li Li, Ying Tang, Qing Shan Yang

Henry M. Rowan College of Engineering Departmental Research

Remanufacturing is a practice of growing importance due to increasing environmental awareness and regulations. However, the stochastic natures inherent in the remanufacturing processes complicate its scheduling. This paper undertakes the challenge and presents a remanufacturing job shop scheduling approach by integrating alternative routing assignment and machine resource dispatching. A colored timed Petri net is introduced to model the dynamics of remanufacturing process, such as various process routings, uncertain operation times for cores, and machine resource conflicts. With the color attributes in Petri nets, two types of decision points, recovery routing selection and resource dispatching, are introduced and linked with places …


Managing Healthcare Data Assets As A Complex Adaptive System, Katie Clifton Mar 2019

Managing Healthcare Data Assets As A Complex Adaptive System, Katie Clifton

Systems Science Friday Noon Seminar Series

A major project is underway to develop a shared platform for data and analytics in a highly federated healthcare delivery organization. In the status quo data environment, analysts have integrated information from various domains — medical records, claims, membership — to produce a multitude of reports and analysis. Duplicative, mis-aligned, and siloed datasets were created as an unintended consequence.

One objective of the project is to produce outcomes (reports, analysis) that are more standardized and efficient than the status quo without sacrificing adaptability. Standards and practices are being intentionally developed as a mechanism for this emerging system to achieve more …


An Artificial Bee Colony-Based Hybrid Approach For Waste Collection Problem With Midway Disposal Pattern, Qu Wei, Zhaoxia Guo, Hoong Chuin Lau, Zhenggang He Mar 2019

An Artificial Bee Colony-Based Hybrid Approach For Waste Collection Problem With Midway Disposal Pattern, Qu Wei, Zhaoxia Guo, Hoong Chuin Lau, Zhenggang He

Research Collection School Of Computing and Information Systems

This paper investigates a waste collection problem with the consideration of midway disposal pattern. An artificial bee colony (ABC)-based hybrid approach is developed to handle this problem, in which the hybrid ABC algorithm is proposed to generate the better optimum-seeking performance while a heuristic procedure is proposed to select the disposal trip dynamically and calculate the carbon emissions in waste collection process. The effectiveness of the proposed approach is validated by numerical experiments. Experimental results show that the proposed hybrid approach can solve the investigated problem effectively. The proposed hybrid ABC algorithm exhibits a better optimum-seeking performance than four popular …


Development Of A Myoelectric Detection Circuit Platform For Computer Interface Applications, Nickolas Andrew Butler Mar 2019

Development Of A Myoelectric Detection Circuit Platform For Computer Interface Applications, Nickolas Andrew Butler

Master's Theses

Personal computers and portable electronics continue to rapidly advance and integrate into our lives as tools that facilitate efficient communication and interaction with the outside world. Now with a multitude of different devices available, personal computers are accessible to a wider audience than ever before. To continue to expand and reach new users, novel user interface technologies have been developed, such as touch input and gyroscopic motion, in which enhanced control fidelity can be achieved. For users with limited-to-no use of their hands, or for those who seek additional means to intuitively use and command a computer, novel sensory systems …


36% Reduction In Fuel Resupply Using A Hybrid Generator & Battery System For An Austere Location, David J. Chester, Torrey J. Wagner, Douglas S. Dudis Mar 2019

36% Reduction In Fuel Resupply Using A Hybrid Generator & Battery System For An Austere Location, David J. Chester, Torrey J. Wagner, Douglas S. Dudis

Faculty Publications

The DOD energy policy is to increase energy security resiliency, and mitigate costs in the use and management of energy[1] Forward operating bases (FOBs) are remote, austere base camps that support an operationally defined mission with a limited or no ability to draw from an energy grid and have historically relied on diesel-powered generators for the primary production of energy.[2] Generators are sized to meet a theoretical peak demand, but steady state loads are far below this peak, resulting in under-loaded generators.[3] Under-loaded diesel generators decrease efficiency and increase the need for maintenance, affecting the lifespan of …


Analogies And Comparisons For Stm Data Bodies, Phillip M. Cunio, Brien Flewelling Feb 2019

Analogies And Comparisons For Stm Data Bodies, Phillip M. Cunio, Brien Flewelling

Space Traffic Management Conference

Space Traffic Management (STM) has already demonstrated its potential to be extremely data-intensive. The large number of objects on orbit today, if observed constantly throughout their lifetimes, could produce a staggeringly large number of observations that might in turn generate large numbers of orbits. Orbit data with a lengthy time history can be used to produce estimates of maneuver frequency, susceptibility to natural forces such as drag, and (if combined with photometric data) assessments of behavioral patterns of life.

A future of mega-constellations and a growing number of nations and organizations with assets on orbit would make it likely that …


A Statistical Approach For Commercial Space Vehicle Integration Into The National Airspace System, Christopher Hays, Daniel Chu, Pedro Llanos Feb 2019

A Statistical Approach For Commercial Space Vehicle Integration Into The National Airspace System, Christopher Hays, Daniel Chu, Pedro Llanos

Space Traffic Management Conference

This paper explores commercial space vehicle (CSV) suborbital flight trajectories in the temporal and spatial domains for CSV integration into the National Airspace System. The research data was collected via the Suborbital Space Flight Simulator (SSFS) housed in the College of Aviation at Embry-Riddle Aeronautical University - Daytona Beach campus, and analyzed using an original MATLAB data analytics tool. This study primarily focuses on statistical trends observed in previously simulated flights supported by three Project PoSSUM (Polar Suborbital Science in the Upper Mesosphere) campaigns comprised of 34 flights and 19 control flights, and to identify relevant milestones in the CSV …


Enhancing Suborbital Science Through Better Understanding Of Wind Effects, Pedro Llanos, Diane Howard Feb 2019

Enhancing Suborbital Science Through Better Understanding Of Wind Effects, Pedro Llanos, Diane Howard

Space Traffic Management Conference

This paper highlights the importance of understanding some key factors, such as winds effects, trajectory and vehicle parameters variations in order to streamline the space vehicle operations and enhance science in the upper mesosphere at about 85 km. Understanding these effects is crucial to refine current space operations and establish more robust procedures. These procedures will involve training new space operators to conduct and coordinate space operations in class E above FL600 airspace within the Air Traffic Organization (ATO).

Space vehicles such as Space Ship Two can spend up to 6 minutes in class E airspace above FL600 after launch. …


Iot And Digitization Will Reconnect System Engineering And Science, John Blyler Feb 2019

Iot And Digitization Will Reconnect System Engineering And Science, John Blyler

Systems Science Friday Noon Seminar Series

The fully connected world is quickly becoming a reality. Architects and developers of this new world must understand both the hardware and software basics of IoT and IIoT systems as well as the proven way to deal with the complexities of the integration of sensors, processors, wireless connectivity, edge to cloud networks, data partitioning and processing, AI, machine language, digital threads and twins, and much more. Such complexity can only be handled with a systems-of-systems (SoS) engineering approach.

But while systems engineering may hold many of the solutions to IoT challenges, systems engineering must evolve from its traditional role. Some …


Project Selection: The $1 Trillion Decisions, Leonard Nethercutt Feb 2019

Project Selection: The $1 Trillion Decisions, Leonard Nethercutt

Operations Management Presentations

This webinar will discuss project selection with a focus on both strategic and fi­nancial factors. Project selection directly influences the future results of a busi­ness either positively or negatively over time. During this presentation, we will examine the important link between strategic management, project management, and operations management to create future results and value. You will learn project selection methods and tips to help your organization make a positive impact on the future of your business.


Optimal Design And Implementation Of Fractal Dipole Antenna Based On Arc Of Trigeminal Tree Structure, Xiaohong Zhang, Xiaoxiao Nan, Yixian Yang Feb 2019

Optimal Design And Implementation Of Fractal Dipole Antenna Based On Arc Of Trigeminal Tree Structure, Xiaohong Zhang, Xiaoxiao Nan, Yixian Yang

Journal of System Simulation

Abstract: A RFID fractal dipole antenna is designed with the arc of the trigeminal tree structure, which is fed by simple microstrip balun to achieve better impedance matching within employing double parallel line structure and by using the dielectric substrate withεr=4.4 and tan δ=0.035. The results of electromagnetic property simulation analysis of HFSS show that the return loss can reach 36dB, which is much higher than binary arc-shaped fractal antenna which is 16dB; and the impedance matching is very ideal. By physical processing and testing of the antenna, the measured results are in very good agreement with simulation …


Blind Separation Simulation System Of Sound Signals Based On Time-Frequency Analysis Of Short Time Fourier Transformation, Xiaorong Tong Feb 2019

Blind Separation Simulation System Of Sound Signals Based On Time-Frequency Analysis Of Short Time Fourier Transformation, Xiaorong Tong

Journal of System Simulation

Abstract: In order to improve the ability of real-time and separation accuracy, a blind separation algorithm based on time-frequency (TF) analysis of short time Fourier transformation is proposed, and the problems of underdetermined sound signal sorting can be solved effectively. The proposed method avoids some of the drawbacks, relaxes the assumption by allowing the sources to be TF-non-disjoint to a certain extent, and the algorithm can be achieved in the condition of TF-non-disjoint. This method was successfully applied to sound signal sorting system; the time domain waves of signals can be got; and the whole signal sorting process can be …


Evaluation Of Flow Line Structure Of Hospital With Spatial Cognitive Agent, Yunfeng Wang Feb 2019

Evaluation Of Flow Line Structure Of Hospital With Spatial Cognitive Agent, Yunfeng Wang

Journal of System Simulation

Abstract: Hospital flow line is the result of the mutual adaptation of its spatial layout and business process, which should be regarded as an independent analysis unit in the spatial layout design. Aiming at the phenomenon that the flow lines have the characteristics of both space and flow and are difficult to analyze, a spatial cognitive process of agents is established by introducing structural elements from the spatial syntax analysis as the knowledge coding language of agents. Evaluation indexes of hospital flow line structure based on computational experiment are proposed and implemented. The framework of flow line analysis combining flow …


Evaluation And Modeling Of Visual Fatigue In 3d Display Based On Ecg, Danli Wang, Xinpan Yang, Yue Kang, Haichen Hu Feb 2019

Evaluation And Modeling Of Visual Fatigue In 3d Display Based On Ecg, Danli Wang, Xinpan Yang, Yue Kang, Haichen Hu

Journal of System Simulation

Abstract: This study investigates and models the correlation between visual fatigue and ECG data by collecting the ECG data of the participants during watching 3D movies, combining with the subjective scores, the reaction time, and the questionnaires before and after the experiment. ECG data of 12 subjects were analyzed in both time and frequency domain. The results showed that subjective score and HR increased with the duration of viewing, while PNN50 decreased. Linear model of subjective score is established, and the R² of model is 0.930. Subjective questionnaires show significant changes in overall visual fatigue, dry eyes and nausea symptoms …


Centroidal Voronoi Tessellation With Local Optimization, Tianyu Ye, Yiqun Wang, Dongming Yan, Junhai Yong Feb 2019

Centroidal Voronoi Tessellation With Local Optimization, Tianyu Ye, Yiqun Wang, Dongming Yan, Junhai Yong

Journal of System Simulation

Abstract: Centroidal Voronoi tessellation is a special geometric structure, which has many applications in various fields such as geographical information system, signal processing, mesh generation/optimization, visualization and so on. Due to the highly non-convex nature of the CVT energy function, the existing methods for computing CVT have several drawbacks, which always trap into local minima. We propose generation optimization and stochastic optimization schemes for further reducing the CVT energy. Experimental results show that the proposed method improves both quality and efficiency compared to the recent approaches.


Satellite Formation Keeping And Its Stability Analysis Based On Artificial Potential Field Method, Shengqing Yang, Wenyu Ye, Yubin He, Yabin Wan Feb 2019

Satellite Formation Keeping And Its Stability Analysis Based On Artificial Potential Field Method, Shengqing Yang, Wenyu Ye, Yubin He, Yabin Wan

Journal of System Simulation

Abstract: In this paper, a control method of satellite formation keeping is investigated based on artificial potential field. Since the N-body problem doesn’t have analytical solutions, a leader-follower formation is proposed as a restricted N-body problem. The stable structure has infinite possible pairs of coordinates in the inertial frame, therefore the Jacobian matrix of the corresponding error dynamic system at the equilibrium point is unsolvable. By introducing a transformation of coordinates from inertial frame to a specific reference frame, the stability analysis of error dynamic system is only related to the structure of formation. By the reduction of error …


Structure Optimization Analysis Of Distillation Kettle Based On Elastic-Plastic Mechanics, Xiaodong Hu, Liu Ning, Xiangsong Qi, Jianpeng Wang Feb 2019

Structure Optimization Analysis Of Distillation Kettle Based On Elastic-Plastic Mechanics, Xiaodong Hu, Liu Ning, Xiangsong Qi, Jianpeng Wang

Journal of System Simulation

Abstract: Based on the analysis of structural strength by elastic mechanics, there is a large stress singularity due to the discontinuity of the equipment structure, which makes the calculation result not consistent with the actual stress of the equipment. According to the actual design and structure of a distillation reactor, based on the theory of elastic-plastic mechanics, through modeling, meshing, loading and constraint analysis, the stress distribution of distillation kettle is analyzed; and the wall thickness and stiffener structure are optimized. The results show that the calculation results are reliable and the design of wall thickness is smaller than the …


Overview Of Image Segmentation And Registration For Spine Biological Modeling, Juping Gu, Tianyu Cheng, Hua Liang, Jianping Wang, Zhao Jian, Cao Yong Feb 2019

Overview Of Image Segmentation And Registration For Spine Biological Modeling, Juping Gu, Tianyu Cheng, Hua Liang, Jianping Wang, Zhao Jian, Cao Yong

Journal of System Simulation

Abstract: The prevalence of common spinal fractures is high in this day. Spinal image segmentation and registration are the key step and prerequisite of target recognition, biomechanical modeling and finite element analysis. They are also the key technology of noninvasive surgery navigation. Aiming at the problems of spinal image processing, the classical medical image segmentation and registration algorithm is introduced. It also analyzes the defects and prospects of the future development trend of spine image processing. The research results have certain significance for further understanding of spinal medical image processing and promoting the development of rehabilitation therapy for spinal fractures.


Traffic Patterns For Intelligent Vehicles In The Intersection, Wang Jian, Feng Qi, Xiaowei Hu Feb 2019

Traffic Patterns For Intelligent Vehicles In The Intersection, Wang Jian, Feng Qi, Xiaowei Hu

Journal of System Simulation

Abstract: With the applications of GPS/DR/MM integrated positioning technology and vehicle infrastructure integration technology, three traffic patterns with which intelligent vehicles go through the intersection are put forward. These three traffic patterns include signal lights adaptive traffic pattern, vehicle self-organizing traffic pattern and vehicle infrastructure integration traffic pattern. They can reduce vehicle delay, avoid traffic conflicts, decrease the probability of traffic accidents, improve traffic efficiency and realize the barrier-free accessibility of intelligent vehicles to the intersection. According to the parameters such as vehicles arrival rate, critical velocity and the average vehicle spacing, a clearance movement model and a circular path …


Modeling And Simulation Of Car-Following On Expressway, Yuhan Jia, Jianping Wu, Yiman Du, Mingyu Liu Feb 2019

Modeling And Simulation Of Car-Following On Expressway, Yuhan Jia, Jianping Wu, Yiman Du, Mingyu Liu

Journal of System Simulation

Abstract: Aiming at the high-speed following phenomenon on expressways, an improved car-following model is developed in the paper considering variable safety headway distance. The new model is calibrated and validated by the data collected using an instrumented vehicle in Beijing. Stability analysis of the new model is investigated using the control theory method. The numerical simulations are implemented and the result shows good consistency with theoretical study. The new model is integrated into the traffic simulation system of FLOWSIM. Experiment results show that the improved OV model based FLOWSIM can outperform the original system on some specific conditions.


Evaluation Method Of Imminent Battle Situation In Air Combat, Huimin Cao, Anxiang Huang, Lei Xiang Feb 2019

Evaluation Method Of Imminent Battle Situation In Air Combat, Huimin Cao, Anxiang Huang, Lei Xiang

Journal of System Simulation

Abstract: In the state of air combat, the situation change rapidly. Quick and accurate assessment of the current situation and making decisions is the key to the victory of air combat and the preservation of own strength. Based on the specialty of the modern air battle and pelagic operation, this article adds the political factor, the pilot individual actual combat ability, and the formation cooperative tactical task to fight against the single constraint into the evaluation index system. This makes the evaluation more reasonable and comprehensive and closer to the actual combat, so as to provide more accurate basis for …


3d Flight Trajectory Simulation Generator Based On Track Constraints, Shuguang Sun, Cheng Peng Feb 2019

3d Flight Trajectory Simulation Generator Based On Track Constraints, Shuguang Sun, Cheng Peng

Journal of System Simulation

Abstract: The airborne navigation equipment needs accurate flight trajectory data to test its performance. According to the requirements of the Beidou receivers, considering the constraint of trajectory and flight performance, a flight trajectory generator is designed using iteration like method. The flight trajectory generator can generate the whole trajectory data and the flight parameters of the aircraft based on the actual flight procedures, and display the data and parameters in real time. The whole flight trajectory simulation data from Beijing International Capital Airport to Guangzhou Baiyun International Airport is generated. The result shows that the flight trajectory generator can generate …


Modular Design Method Of Integrated Avionics Simulation System, Mingbo Zhao, Pan Long, Longwei Jiang, Wang Gang, Guangxing Zhao Feb 2019

Modular Design Method Of Integrated Avionics Simulation System, Mingbo Zhao, Pan Long, Longwei Jiang, Wang Gang, Guangxing Zhao

Journal of System Simulation

Abstract: In the past, there were some problems in the software design for the flight simulation avionics system such as the decentralized structure and the low degree of modularization. Aiming at these problems, a hierarchical, modular integrated avionics system is constructed. The logic part dispersed in each function module is independent to form the integrated logic module. Each task function module and its sub module are responsible for the calculation of the relevant task function algorithm. Modular design is carried out in a deeper level. By dataflow analysis, each module in this design has strong cohesion and weak coupling and …


Rehabilitation Training System Based On Brain Computer Interface, Banghua Yang, Li Bo Feb 2019

Rehabilitation Training System Based On Brain Computer Interface, Banghua Yang, Li Bo

Journal of System Simulation

Abstract: Brain-computer interface (BCI) is a new communication and control method. The BCI rehabilitation training system was developed for rehabilitation training of post-stroke patients by using MATLAB and VC++ hybrid programming method. By decoding the EEG signal, the patient's movement intention can be recognized accurately in real time, then the work of the rehabilitation peripheral is triggered to give feedback from the visual, auditory, and tactile. The patient's active rehabilitation is achieved through the system. The system has the characteristics of user-friendly interface, modular algorithm, high online recognition rate; and it can be used as a reference for BCI-based …