Operations Research, Systems Engineering and Industrial Engineering Commons^™

Bullwhip Effect Of A Closed Leep Supply Chain With And Without Information Sharing Of Customer Demand, Jui-Hsin Hsu

Theses and Dissertations

In recent years, companies have become interested in a closed-loop supply chain that is concerned with the recovery pipeline. The expenses of a company can be influenced by large inventories and backlogs due to the bullwhip effect in the supply chain. Previous literature has shown that the bullwhip effect can be decreased by a reverse supply chain. This paper develops a closed-loop supply chain including seven echelons for recovery of end-of-life products. The model considers the order-up-to inventory policy and the exponential smoothing forecasting with a trend method in the system to assist in determining the ordering quantities. The best …

ℓ-Ctp: Utilizing Multiple Agents To Find Efficient Routes In Disrupted Networks, Andrew Alseth

Graduate Theses and Dissertations

Recent hurricane seasons have demonstrated the need for more effective methods of coping with flooding of roadways. A key complaint of logistics managers is the lack of knowledge when developing routes for vehicles attempting to navigate through areas which may be flooded. In particular, it can be difficult to re-route large vehicles upon encountering a flooded roadway. We utilize the Canadian Traveller’s Problem (CTP) to construct an online framework for utilizing multiple vehicles to discover low-cost paths through networks with failed edges unknown to one or more agents a priori. This thesis demonstrates the following results: first, we develop the …

Simulation Research On Armored Equipment Maintenance Support Resource Optimization, Huiqi Zhang, Chunliang Chen, Junyan Liu, Liu Shuai, Yongqing Zhang

Journal of System Simulation

Abstract: Contraposing the problem of armored equipment maintenance resource computation and optimization, the armored equipment maintenance support process was analyzed. The armored equipment maintenance support process concept model and the mathematic model were constructed based on discrete system modeling theory; while the simulation model based on net discrete event was given in apply of Anylogic software. The armored equipment maintenance support task fulfilling degree, the resource utilization degree, and the mean maintenance time were got by simulation computation. As a result that maintenance support resource was evaluated based on index weight, and the optimized values of the maintenance support resource …

Cost Analysis Of Optimized Islanded Energy Systems In A Dispersed Air Base Conflict, Jay F. Pearson, Torrey J. Wagner, Justin D. Delorit

Faculty Publications

The United States Air Force has implemented a dispersed air base strategy to enhance mission effectiveness for near-peer conflicts. Asset dispersal places many smaller bases across a wide geographic area, which increases resupply requirements and logistical complexity. Hybrid energy systems reduce resupply requirements through sustainable, off-grid energy production. This paper presents a novel hybrid energy renewable delivery system (HERDS) model capable of (1) selecting the optimal hybrid energy system design that meets demand at the lowest net present cost and (2) optimizing the delivery of the selected system using existing Air Force cargo aircraft. The novelty of the model’s capabilities …

Quadratic Rational Trigonometric Spline Curves With Shape Controlling, Xinru Liu, Manman Wei, Shengjun Liu, Dangfu Yang

Journal of System Simulation

Abstract: A new quadratic rational trigonometric spline curve with a shape parameter was proposed. The value control and the inflection-point control of the interpolation scheme were discussed in theory. And the optimal methods for calculating the desired inflection-points was proposed, by using optimization theory. Numerical experiments show the interpolation spline and the optimization method can be used in modeling design.

Adaptive Quick Artificial Bee Colony Algorithm Based On Opposition Learning, Xiaojian Yang, Yiwei Dong

Journal of System Simulation

Abstract: On the basis of analyzing such shortcomings of the artificial bee colony algorithm (ABC) as slow convergence, low convergence precision and premature convergence, the opposition-learning adaptive quick artificial bee colony algorithm (OAQABC) was proposed. A new step size was proposed, which made the around food source parameter of quick artificial bee colony algorithm (QABC) adaptive, and combined the opposition-based learning to improve the employed bee phase. The experimental results show that OAQABC has better performance than basic ABC and QABC. Also the optimization performance of OAQABC is better than particle swarm optimization (PSO) algorithm and Cuckoo Search (CS) algorithm …

Affinity Propagation Based Improved Group Search Optimizer Clustering Algorithm, Zhang Kang, Xingsheng Gu

Journal of System Simulation

Abstract: The essence of clustering is an optimization problem. It can be solved by swarm intelligent algorithms which are the popular research area in recent years. A novel Group Search Optimizer (GSO) algorithm named Fast Global Group Search Optimizer (FGGSO) was proposed. FGGSO improved the individuals' updating strategies of GSO, adopting the campaign strategy, destruction-construction strategy and accelerating-jumping strategy. By this means, the proposed algorithm improved the global and local search capability of the original GSO. Furthermore, based on this FGGSO algorithm, a novel improved AP algorithm was proposed. On account of deficiency of AP clustering unable to deal with …

Least-Energy Maneuver Of Five-Link Manipulator Constrained Within Tunnel Space Using Direct Collocation, Xiuqiang Pan, Chengcai Mei, Junjie Chen

Journal of System Simulation

Abstract: Optimal control and designs least-energy maneuver control laws for a five-linked manipulator were applied in order to carry out designated tasks in a confined space. Lagrange-Euler equation described the relationships between the actuators and system dynamics. Euler-Lagrange formulation indicates how optimization can be achieved when optimum occurs. Direct collocation method was introduced in order to solve this highly nonlinear dynamic optimal control problem. Simulations were done to exploit how the manipulator reacted to the constraint. In this study, the diameter of the cylindrical space was shrunken each time by 0.1 meters. The value of the cost function and …

Optimization Scheme Of Average Time For Finding Idle Channel In Cognitive Radio System, Qiao Pei, Liyuan Xiao, Yanyan Han, Gao Ling

Journal of System Simulation

Abstract: In cognitive radio system, periodic spectrum sensing was taken by secondary users to prevent the interference to primary users. Supposed that there are many primary user channels, when the current primary user occupies channel, secondary users do spectrum handover. During spectrum handover, the time of finding an idle channel is a random variable. In order to speed up spectrum handover, the system used equal gain combining cooperative spectrum sensing to inspect an idle channel. This pattern optimized the sensing time of the single user channel, in order to get the best effect of the average time in finding idle …

Parameters Optimization For Variable Speed And Pitch Controller Of Wind Turbine Based On Bladed, Gao Feng, Wang Wei, Xinmei Ling

Journal of System Simulation

Abstract: Due to nonlinearity and time-varying parameters of wind power system, its controller parameters are hard to be calculated and tuned during the process of design and optimization. The linear model which is suitable for parameters tuning was built through model linearization of Bladed and model reducing-order algorithm. The PI parameter was tuned with the IM-PSO (Immune Memory Particle Swarm Optimization). Moreover, the gain coefficient of optimal torque control and the gain divisor of adaptive PI pitch control conducted optimizing calculation based on the identification parameters of Bladed. A set of optimization method for variable speed and pitch controller …

Real-Time Control Method Of Hsss Based On Single Phrase Self Decoupling Strategy, Yingping Yi, Bogang Qu, Zhang Yang

Journal of System Simulation

Abstract: Zero Crossing Detection (ZCD) and phase locked loop are widely applied in the real-time control. Compared the performances of ZCD, SSRF SPLL and DDSRF SPLL,a method named as Single Phase Self Decoupling SPLL (SPSD SPLL) for HSSS(Hybrid Solid State Switch) is proposed and the mathematical method and control methods are given. The control parameters were obtained by analyzing the steady and dynamic performance of SPSD SPLL. By establishing the real-time controlling models based on the above strategies and HSSS model in the MATLAB/Simulink, the simulation and optimization analysis results verified that the SPSD SPLL was well performed …

Scheduling Problem Of Unidirectional Material Handling System With Short-Cut, Juntao Li, Kun Xia, Kise Hiroshi

Journal of System Simulation

Abstract: Unidirectional circulation-type material handling system on a single loop with a shortcut is a typical and basic unit in a flexible manufacturing system or logistics system. It is widely used in semiconductor wafer fabrication system. Superposition efficiency of the basic unit often determines the one of the whole system. Different scheduling rules impact the interference between AGVs and then have an important effect on the efficiency of the whole system. To decrease the interference and improve performance of the system, a mathematical model of this system was made, analyzing this system by simulation and comparing the merits and …

Study On Vacuum Dehydration Rate From Oil Based On T_S Fuzzy Identifying Model, Liu Ge, Bin Chen, Xianming Zhang

Journal of System Simulation

Abstract: The process of vacuum dehydration from oil is time-varying, nonlinear, and difficult to be specified with mathematical methods. Takagi-Sugeno (T_S) fuzzy model of vacuum dehydration rate of oil purifier is proposed, which a method of applying Fuzzy C-Means (FCM) clustering algorithm and using the least square method identifying the consequent parameters. The nonlinear mapping is set up from four influence factors (the initial water content, the vacuum pressure , the initial temperature and running time) to vacuum dehydration rate using the T_S fuzzy model. The simulation and experimental results show the T_S model reflects the laws of the influences …

Goods Consumed During Transit In Split Delivery Vehicle Routing Problems: Modeling And Solution, Wenzhe Yang, Di Wang, Wei Pang, Ah-Hwee Tan, You Zhou

Research Collection School Of Computing and Information Systems

This article presents the modeling and solution of an extended type of split delivery vehicle routing problem (SDVRP). In SDVRP, the demands of customers need to be met by efficiently routing a given number of capacitated vehicles, wherein each customer may be served multiple times by more than one vehicle. Furthermore, in many real-world scenarios, consumption of vehicles en route is the same as the goods being delivered to customers, such as food, water and fuel in rescue or replenishment missions in harsh environments. Moreover, the consumption may also be in virtual forms, such as time spent in constrained tasks. …

Improved Particle Swarm Optimization Based On Lévy Flights, Rongyu Li, Wang Ying

Journal of System Simulation

Abstract: The particle swarm optimization (PSO) has some demerits, such as relapsing into local extremum, slow convergence velocity and low convergence precision in the late evolutionary. The Lévy particle swarm optimization (Lévy PSO) was proposed. In the particle position updating formula, Lévy PSO eliminated the impact of speed on the convergence rate, and used Levy flight to change the direction of particle positions movement to prevent particles getting into local optimum value, and then using greedy strategy to update the evaluation and choose the best solution to obtain the global optimum. The experimental results show that Lévy PSO can effectively …

Optimization And Simulation Models To Improve Access To Organ Transplantation In The United States., Fatemeh Karami

Electronic Theses and Dissertations

Organ allocation in the U.S. is administrated by the United Network of Organ Sharing (UNOS). UNOS’s mission is to ensure fair and equitable allocation of organs as stated in the Code of Federal Regulations, which reads "neither place of residence nor place of listing shall be a major determinant of access to transplant". Despite the regulations, there has been endless controversy surrounding the disparity in access to organ transplants. In this context, the primary research goal in this dissertation was to reduce geographic disparity in access to transplants in the U.S., with a focus on heart and kidney transplants. To …

Identifying And Addressing Improvement Opportunities In Primary Care Clinics, Mozhdeh Sadighi

Industrial, Manufacturing, and Systems Engineering Dissertations

ABSTRACT: The main aim of this dissertation is to study how unrecognized opportunities for improving efficiency of in-person patient visits in a primary care clinic can be identified and addressed. To fulfill this goal, the research is divided into three distinct but related sections. Section one, with the most holistic view, uses a combination of scientific and rigorous methods along two research paths and, as a result, explores two opportunities for improvement in the clinic. These opportunities are high patient waiting time and unbalanced workload. Sections two and three each focus on underlying conditions driving one of these two opportunities. …

Curriculum Optimization Via Activity-On-Node Network Modeling, Caroline Rhomberg

Industrial Engineering Undergraduate Honors Theses

University degree plans must be carefully planned so that they allow students the best chance of succeeding. Although for the better, with the advancement of technology and its incorporation into the classroom, it can be argued that the complexity and difficulty of some long-established engineering core classes has changed. With this trend certain combinations of engineering courses have become unfavorable in terms of course withdrawal and fail rates stemming from the interaction of course challenges. A wealth of data has been collected on this topic and will be utilized in this project. As one can imagine, the probability of success …

Locating Emergency Shelters While Incorporating Spatial Factors, Justin Taylor

Graduate Theses and Dissertations

In the immediate response phase of a natural disaster, local governments and nonprofit agencies often establish shelters for affected populations. Decisions regarding at which locations to open shelters are made ad hoc based on available building inventory, and may result in high travel impedance to reach shelters and congestion. This thesis presents a shelter location optimization model based on the two-step floating catchment area (2SFCA) method. The 2SFCA method creates a shelter accessibility score for each areal unit (e.g., census block group) which represents the ability for persons in the unit to access shelter capacity with low travel impedance, relative …

Golng Off The Grid: Optimizing Solar Renewable Energy Systems At Remote Locations To Minimize Logistics Requirements, Increase Sustainability, And Strengthen Energy Assurance, Nathanael J. Thomsen

Theses and Dissertations

Grid-based electrical infrastructure is unavailable at many remote locations including developing nation communities, isolated construction sites, and military contingency bases. Powering these locations with diesel generators requires regular fuel resupply, resulting in increased costs, environmental impacts, and burdensome logistics—making generators an obstacle for energy resiliency and sustainability. This research examines using solar renewable energy systems to replace generators at remote locations and presents a multi-objective optimization model that minimizes logistics variables. Replacing a single deployed generator would save over 500,000 gal of fuel annually, eliminating the need for 100 fuel tanker deliveries.

Computational Model For Neural Architecture Search, Ram Deepak Gottapu

Doctoral Dissertations

"A long-standing goal in Deep Learning (DL) research is to design efficient architectures for a given dataset that are both accurate and computationally inexpensive. At present, designing deep learning architectures for a real-world application requires both human expertise and considerable effort as they are either handcrafted by careful experimentation or modified from a handful of existing models. This method is inefficient as the process of architecture design is highly time-consuming and computationally expensive.

The research presents an approach to automate the process of deep learning architecture design through a modeling procedure. In particular, it first introduces a framework that treats …

Route Planning For Long-Term Robotics Missions, Christopher Alexander Arend Tatsch

Graduate Theses, Dissertations, and Problem Reports

Many future robotic applications such as the operation in large uncertain environment depend on a more autonomous robot. The robotics long term autonomy presents challenges on how to plan and schedule goal locations across multiple days of mission duration. This is an NP-hard problem that is infeasible to solve for an optimal solution due to the large number of vertices to visit. In some cases the robot hardware constraints also adds the requirement to return to a charging station multiple times in a long term mission. The uncertainties in the robot model and environment require the robot planner to account …

Efficiency Analysis Of A Congested Brazilian Airport Applying Slots Optimization Control: Congonhas Airport Case, Mariana Franco B. Mendes, Rafael Roco De Araujo, Ana Paula Beck Da Silva Etges, Massoud Bazargan

International Journal of Aviation, Aeronautics, and Aerospace

The current slot allocation mechanism in Brazil, based on the International Air Transport Association (IATA) rules, and its supplementary local regulation The National Civil Aviation Agency (ANAC), displays a few issues and limitations (e.g. slot misuse, allocation inefficiencies). Such issues are particularly present in the case of busy airports that works near their maximum capacity for major parts of the day. This inefficiency problem is generated because of the complexity of slot allocation added to the limited decision support available for the Brazilian system. This study focuses on the implementation of an optimal slot model, based on IATA regulations with …